WorldWideScience

Sample records for ground coil heat

  1. Helically coiled tube heat exchanger

    International Nuclear Information System (INIS)

    Harris, A.M.

    1981-01-01

    In a heat exchanger such as a steam generator for a nuclear reactor, two or more bundles of helically coiled tubes are arranged in series with the tubes in each bundle integrally continuing through the tube bundles arranged in series therewith. Pitch values for the tubing in any pair of tube bundles, taken transverse to the path of the reactor coolant flow about the tubes, are selected as a ratio of two unequal integers to permit efficient operation of each tube bundle while maintaining the various tube bundles of the heat exchanger within a compact envelope. Preferably, the helix angle and tube pitch parallel to the path of coolant flow are constant for all tubes in a single bundle so that the tubes are of approximately the same length within each bundle

  2. Measurement of heating coil temperature for e-cigarettes with a "top-coil" clearomizer.

    Science.gov (United States)

    Chen, Wenhao; Wang, Ping; Ito, Kazuhide; Fowles, Jeff; Shusterman, Dennis; Jaques, Peter A; Kumagai, Kazukiyo

    2018-01-01

    To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a "top-coil" clearomizer, and to make associations of coil conditions with emission of toxic carbonyl compounds by combining results herein with the literature. The coil temperature of a second generation e-cigarette was measured at various applied power levels, coil conditions, and e-liquid compositions, including (1) measurements by thermocouple at three e-liquid fill levels (dry, wet-through-wick, and full-wet), three coil resistances (low, standard, and high), and four voltage settings (3-6 V) for multiple coils using propylene glycol (PG) as a test liquid; (2) measurements by thermocouple at additional degrees of coil wetness for a high resistance coil using PG; and (3) measurements by both thermocouple and infrared (IR) camera for high resistance coils using PG alone and a 1:1 (wt/wt) mixture of PG and glycerol (PG/GL). For single point thermocouple measurements with PG, coil temperatures ranged from 322 ‒ 1008°C, 145 ‒ 334°C, and 110 ‒ 185°C under dry, wet-through-wick, and full-wet conditions, respectively, for the total of 13 replaceable coil heads. For conditions measured with both a thermocouple and an IR camera, all thermocouple measurements were between the minimum and maximum across-coil IR camera measurements and equal to 74% ‒ 115% of the across-coil mean, depending on test conditions. The IR camera showed details of the non-uniform temperature distribution across heating coils. The large temperature variations under wet-through-wick conditions may explain the large variations in formaldehyde formation rate reported in the literature for such "top-coil" clearomizers. This study established a simple and straight-forward protocol to systematically measure e-cigarette coil heating temperature under dry, wet-through-wick, and full-wet conditions. In addition to applied power, the

  3. Hydrodynamic studies of CNT nanofluids in helical coil heat exchanger

    Science.gov (United States)

    Babita; Sharma, S. K.; Mital Gupta, Shipra; Kumar, Arinjay

    2017-12-01

    Helical coils are extensively used in several industrial processes such as refrigeration systems, chemical reactors, recovery processes etc to accommodate a large heat transfer area within a smaller space. Nanofluids are getting great attention due to their enhanced heat transfer capability. In heat transfer equipments, pressure drop is one of the major factors of consideration for pumping power calculations. So, the present work is aimed to study hydrodynamics of CNT nanofluids in helical coils. In this study, pressure drop characteristics of CNT nanofluid flowing inside horizontal helical coils are investigated experimentally. The helical coil to tube diameter was varied from 11.71 to 27.34 keeping pitch of the helical coil constant. Double distilled water was used as basefluid. SDBS and GA surfactants were added to stablilize CNT nanofluids. The volumetric fraction of CNT nanofluid was varied from 0.003 vol% to 0.051 vol%. From the experimental data, it was analyzed that the friction factor in helical coils is greater than that of straight tubes. Concentration of CNT in nanofluids also has a significant influence on the pressure drop/friction factor of helical coils. At a constant concentration of CNT, decreasing helical coil to tube diameter from 27.24 to 11.71, fanning friction factor of helical coil; f c increases for a constant value of p/d t. This increase in the value of fanning friction factor can be attributed to the secondary flow of CNT nanofluid in helical coils.

  4. Development of Ground Coils with Low Eddy Current Loss by Applying the Compression Molding Method after the Coil Winding

    Science.gov (United States)

    Suzuki, Masao; Aiba, Masayuki; Takahashi, Noriyuki; Ota, Satoru; Okada, Shigenori

    In a magnetically levitated transportation (MAGLEV) system, a huge number of ground coils will be required because they must be laid for the whole line. Therefore, stable performance and reduced cost are essential requirements for the ground coil development. On the other hand, because the magnetic field changes when the superconducting magnet passes by, an eddy current will be generated in the conductor of the ground coil and will result in energy loss. The loss not only increases the magnetic resistance for the train running but also brings an increase in the ground coil temperature. Therefore, the reduction of the eddy current loss is extremely important. This study examined ground coils in which both the eddy current loss and temperature increase were small. Furthermore, quantitative comparison for the eddy current loss of various magnet wire samples was performed by bench test. On the basis of the comparison, a round twisted wire having low eddy current loss was selected as an effective ground coil material. In addition, the ground coils were manufactured on trial. A favorable outlook to improve the size accuracy of the winding coil and uneven thickness of molded resin was obtained without reducing the insulation strength between the coil layers by applying a compression molding after winding.

  5. Heat pipes for ground heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L L

    1988-01-01

    Different versions of heat pipe ground heating and cooling devices are considered. Solar energy, biomass, ground stored energy, recovered heat of industrial enterprises and ambient cold air are used as energy and cold sources. Heat pipe utilization of air in winter makes it possible to design accumulators of cold and ensures deep freezing of ground in order to increase its mechanical strength when building roadways through the swamps and ponds in Siberia. Long-term underground heat storage systems are considered, in which the solar and biomass energy is accumulated and then transferred to heat dwellings and greenhouses, as well as to remove snow from roadways with the help of heat pipes and solar collectors.

  6. Developing mixed convection in a coiled heat exchanger

    NARCIS (Netherlands)

    Sillekens, J.J.M.; Rindt, C.C.M.; Steenhoven, van A.A.

    1998-01-01

    In this paper the development of mixed convection in a helically coiled heat exchanger for Re = 500, Pr = 5 and d = 1/14 is studied. The influence of buoyancy forces (Gr = ¢O (105)) on heat transfer and secondary flow is analyzed. In the method used the parabolized equations are solved using a

  7. Developing mixed convection in a coiled heat exchanger

    NARCIS (Netherlands)

    Sillekens, J.J.M.; Rindt, C.C.M.; Steenhoven, van A.A.

    1998-01-01

    In this paper the development of mixed convection in a helically coiled heat exchanger for Re = 500, Pr = 5 and
    δ =114
    is studied. The influence of buoyancy forces ¢
    (Gr = ¢O (105))
    on heat transfer and secondary flow is analyzed. In the method used the parabolized equations are

  8. Novel Coil Winding Method to Realize Pot Heated Evenly

    Institute of Scientific and Technical Information of China (English)

    Mao-Yan Wang; Hai-Long Li; Meng Zhang; Zhi-Tao Xu; Cui-Lin Zhong; Jun Xu

    2015-01-01

    To solve the problem about the inhomogeneous thermal effect of pot heated by coils along the circumference, a novel coil winding method is proposed and compared with the general winding method in the paper. First, based on the Biot-Savart law and Ampere’s rule, the magnetic induction generated by a straight current carrying conductor and a current loop is discussed, respectively. Then the novel coil winding method is developed by adjusting the location of inhomogeneous joints. The joints are periodically scattered along the circumferential direction and symmetrically designed around the central axis. Numerical results show that the quite non-uniform temperature in the base of pot at the circular direction is effectively improved by using the proposed winding method. The potential danger produced by high temperature at some region of coils plate is minimized. It is energy-efficient and safe for residential appliances.

  9. Induction heating using induction coils in series-parallel circuits

    Science.gov (United States)

    Matsen, Marc Rollo; Geren, William Preston; Miller, Robert James; Negley, Mark Alan; Dykstra, William Chet

    2017-11-14

    A part is inductively heated by multiple, self-regulating induction coil circuits having susceptors, coupled together in parallel and in series with an AC power supply. Each of the circuits includes a tuning capacitor that tunes the circuit to resonate at the frequency of AC power supply.

  10. Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness

    Science.gov (United States)

    Andrzejczyk, Rafał; Muszyński, Tomasz

    2016-12-01

    The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow inside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

  11. Research of the heat exchanging processes running in the heating and hot water supply loops of the coil heat exchangers

    Directory of Open Access Journals (Sweden)

    Ірина Геннадіївна Шитікова

    2016-11-01

    Full Text Available The fuel-energy complex research has made it possible to disclose a huge power-saving potential in the municipal heat-and-power engineering. Power-and-resource-saving units and systems are becoming extremely urgent because of the power engineering crisis expansion. The self-adjusting heat supply system from the individual heating points with the heat-accumulating units and coil heat exchangers for independent heating and water supply systems has been examined. Coil heat exchangers are used in municipal heating for heat transfer (e.g. geothermal waters for the independent mains of the heating and hot water supply systems. The heat engineering calculation of the heating and accumulating unit with the coil heat exchanger for independent heat supply systems from individual heater was performed and experimental data were received at the experimental industrial unit under the laboratory conditions. The peculiarities of the flows in the intertubular space, their influence on the heat exchange and temperatures of the first and intermediate mains have been shown. It is important to know the processes running inside the apparatus to be able to improve the technical characteristics of the three-loop coil heat exchanger. The task solution will make it possible to save the materials consumption for the three-loop coil heat exchangers in the future

  12. EXPERIMENTAL INVESTIGATION OF THE CONVECTIVE HEAT TRANSFER IN A SPIRALLY COILED CORRUGATED TUBE WITH RADIANT HEATING

    Directory of Open Access Journals (Sweden)

    Milan Đorđević

    2017-12-01

    Full Text Available The Archimedean spiral coil made of a transversely corrugated tube was exposed to radiant heating in order to represent a heat absorber of the parabolic dish solar concentrator. The main advantage of the considered innovative design solution is a coupling effect of the two passive methods for heat transfer enhancement - coiling of the flow channel and changes in surface roughness. The curvature ratio of the spiral coil varies from 0.029 to 0.234, while water and a mixture of propylene glycol and water are used as heat transfer fluids. The unique focus of this study is on specific boundary conditions since the heat flux upon the tube external surfaces varies not only in the circumferential direction, but in the axial direction as well. Instrumentation of the laboratory model of the heat absorber mounted in the radiation field includes measurement of inlet fluid flow rate, pressure drop, inlet and outlet fluid temperature and 35 type K thermocouples welded to the coil surface. A thermal analysis of the experimentally obtained data implies taking into consideration the externally applied radiation field, convective and radiative heat losses, conduction through the tube wall and convection to the internal fluid. The experimental results have shown significant enhancement of the heat transfer rate compared to spirally coiled smooth tubes, up to 240% in the turbulent flow regime.

  13. Study on Induction Heating Coil for Uniform Mold Cavity Surface Heating

    OpenAIRE

    Yu-Ting Sung; Sheng-Jye Hwang; Huei-Huang Lee; Durn-Yuan Huang

    2014-01-01

    Recently, energy saving is one of the important issues for polymer processing industry. Electromagnetic induction heating has many advantages such as fast heating and low energy consumption. Previous studies using electromagnetic induction heating for rapid tool heating have indicated that the temperature uniformity on a cavity surface is not easy to be achieved. In this paper, two different coils were used for heating uniform 7 mm thick hot work tool steel (JIS SKD61) surface. One is a four-...

  14. Desgn of a 20-MJ superconducting ohmic-heating coil

    International Nuclear Information System (INIS)

    Singh, S.K.; Murphy, J.H.; Janocko, M.A.; Haller, H.E.; Litz, D.C.; Eckels, P.W.; Rogers, J.D.; Thullen, P.

    1979-01-01

    Conceptual designs of 20-MJ superconducting coils which were developed to demonstrate the feasibility of an ohmic-heating system were discussed. The superconductor materials were NbTi and Nb 3 Sn for the pool boil and forced-flow cooling, respectively. The coils were designed to be cryostable for bipolar operation from +7 to -7 tesla maximum field within one second. The structural design addresses the distribution of structure and structural materials used in the pulsed field environment. The cyclic stresses anticipated and the fatigue limits of the structural materials were examined in view of the operating life of the coil. The coils were designed to generate the flux swings while simultaneously meeting the limitations imposed by cooling, insulation, current density and the stresses in the materials. Both the pool and forced cooled conductors have the same criterion for cryostability, i.e., the conductor must return to the superconducting state from an initial temperature of 20 0 K while the full transport current is flowing through the conductor

  15. BI-ground microstrip array coil vs. conventional microstrip array coil for mouse imaging at 7 tesla

    Science.gov (United States)

    Hernández, Ricardo; Terrones, M. A. López; Jakob, P. M.

    2012-10-01

    At high field strengths, the need for more efficient high frequency coils has grown. Since the radiation losses and the interaction between coil and sample increase proportionally to field strength, the quality factor (Q) and the sensitivity of the coil decrease as consequence of these negative effects. Since Zhang et al proposed in 2001 a new surface coil based on the microstrip transmission line for high frequency, different Tx-Rx phased arrays based on this concept have been already introduced in animal and whole body systems at high field strengths, each of them with different modifications in order to get better field homogeneity, SNR or isolation between coil elements in the array. All these arrays for animals systems have been built for rat imaging. One of these modifications is called BI-Ground Microstrip Array Coil (BIGMAC). The implementation of a smaller two-channel BIGMAC design for mouse imaging is studied and its performance compared to a two-channel conventional Microstrip array at 7 Tesla, the higher isolation by using BIGMAC elements in comparison with conventional Microstrip elements is shown in this work.

  16. 46 CFR 153.434 - Heat transfer coils within a tank.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Heat transfer coils within a tank. 153.434 Section 153... Cargo Temperature Control Systems § 153.434 Heat transfer coils within a tank. When a cargo tank... the heat transfer fluid at a pressure greater than the pressure exerted on the heating or cooling...

  17. Heat treatment trials for ITER toroidal field coils

    International Nuclear Information System (INIS)

    Matsui, Kunihiro; Hemmi, Tsutomu; Koizumi, Norikiyo; Nakajima, Hideo; Kimura, Satoshi; Nakamoto, Kazunari

    2012-01-01

    Cable-in-conduit (CIC) conductors using Nb 3 Sn strands are used in ITER toroidal fields (TF) coils. Heat treatment generates thermal strain in CIC conductors because of the difference in thermal expansion between the Nb 3 Sn strands and the stainless-steel jacket. The elongation/shrinkage of the TF conductor may make it impossible to insert a wound TF conductor into the groove of a radial plate. In addition, it is expected that the deformation of the winding due to heat treatment-based release of the residual force in the jacket may also make it impossible to insert the winding in the groove, and that correcting the winding geometry to allow insertion of the winding may influence the superconducting performance of the TF conductor. The authors performed several trials using heat treatment as the part of activities in Phase II of TF coil procurement aiming to resolve the above-mentioned technical issues, and evaluated the elongations of 0.064, 0.074 and 0.072% for the straight and curved conductors and 1/3-scale double-pancake (DP) winding, respectively. It was confirmed that correction if the deformed winding did not influence the superconducting performance of the conductor. (author)

  18. Alternate ohmic heating coil arrangements for compact tokamak

    International Nuclear Information System (INIS)

    Dawson, J.W.; Moretti, A.; Stevens, H.C.; Thompson, K.

    1978-01-01

    The results for a number of ohmic heating (OH) coil arrangements which will allow the reduction of the major radius of Experimental Power Reactor (EPR) tokamaks will be given. In each case the results are compared, at least indirectly, to the reference case, which has the OH solenoid inside the central core of the reactor. The goal for the alternate geometries studied was to stay within the requirements imposed by the EPR conditions on the plasma and to produce as much or more OH V-s as the reference case

  19. Racetrack coil instability resulting from friction-heat generation at fixtures

    International Nuclear Information System (INIS)

    Yazawa, T.; Urata, M.; Chandratilleke, G.R.; Maeda, H.

    1993-01-01

    This paper describes racetrack coil instability resulting from friction-heat generation at fixtures and a preventive measure against it using a thermal barrier. Epoxy impregnated racetrack coils sometimes experience premature quenches due to frictional heat produced by coil slides at fixtures that are essential for the coil straight part to withstand the electromagnetic force. Experimentally, we confirmed for a small-sized racetrack coil that coil slides were actually occurring. The coil movements coupled with acoustic emissions were observed several times when the coil was energized. Each of them was about 10 μm, an equivalent of 20 mJ in frictional heat. This frictional heat was almost comparable with the analytical and experimental coil stability margins when an insulation layer was thin. One of the effective measures against the frictional heat is the thermal barrier, which is a thick insulation layer at the interface between the coil and the fixtures. By thickening the insulation layer from 0.36 to 1.00 mm, the coil stability margin increased from 100 to 200 mJ. (orig.)

  20. Structural analysis of equilibrium and ohmic heating coil assemblies for the TFTR

    International Nuclear Information System (INIS)

    Chattopadhyay, S.

    1975-10-01

    The structural adequacy of the equilibrium and ohmic heating coils and their support systems for the TFTR device has been investigated. The capability of the coils to span ribs of the support structure has been established. The support structure has been found to be effective in resisting the magnetic forces in the coils. The bands encircling the outboard coils and the band tensioning devices have been found to perform adequately. The analysis is based on October 1975 conceptual design

  1. Overview of ground coupled heat pump research and technology transfer activities

    Science.gov (United States)

    Baxter, V. D.; Mei, V. C.

    Highlights of DOE-sponsored ground coupled heat pump (GCHP) research at Oak Ridge National Laboratory (ORNL) are presented. ORNL, in cooperation with Niagara Mohawk Power Company, Climate Master, Inc., and Brookhaven National Laboratory developed and demonstrated an advanced GCHP design concept with shorter ground coils that can reduce installed costs for northern climates. In these areas it can also enhance the competitiveness of GCHP systems versus air-source heat pumps by lowering their payback from 6 to 7 years to 3 to 5 years. Ground coil heat exchanger models (based primarily on first principles) have been developed and used by others to generate less conservative ground coil sizing methods. An aggressive technology transfer initiative was undertaken to publicize results of this research and make it available to the industry. Included in this effort were an international workshop, trade press releases and articles, and participation in a live teleconference on GCHP technology.

  2. Performance of Helical Coil Heat Recovery Exchanger using Nanofluid as Coolant

    Directory of Open Access Journals (Sweden)

    Navid Bozorgan

    2015-07-01

    Full Text Available Nanofluids are expected to be a promising coolant condidate in chemical processes for heat transfer system size reduction. This paper focuses on reducing the number of turns in a helical coil heat recovery exchanger with a given heat exchange capacity in a biomass heating plant using γ-Al2O3/n-decane nanofluid as coolant. The nanofluid flows through the tubes and the hot n-hexane flows through the shell. The numerical results show that using nanofluid as coolant in a helical coil heat exchanger can reduce the manufacturing cost of the heat exchanger and pumping power by reducing the number of turns of the coil.

  3. Modeling of Heat Transfer in the Helical-Coil Heat Exchanger for the Reactor Facility "UNITERM"

    Directory of Open Access Journals (Sweden)

    V. I. Solonin

    2014-01-01

    Full Text Available Circuit heat sink plays an important role in the reactor system. Therefore it imposes high requirements for quality of determining thermal-hydraulic parameters. This article is aimed at modeling of heat exchange process of the helical-coil heat exchanger, which is part of the heat sink circuit of the reactor facility "UNITERM."The simulation was performed using hydro-gas-dynamic software package ANSYS CFX. Computational fluid dynamics of this package allows us to perform calculations in a threedimensional setting, giving an idea of the fluid flow nature. The purpose of the simulation was to determine the parameters of the helical-coil heat exchanger (temperature, velocity at the outlet of the pipe and inter-tubular space, pressure drop, and the nature of the fluid flow of primary and intermediate coolants. Geometric parameters of the model were determined using the preliminary calculations performed by the criterion equations. In calculations Turbulence models k-ε RNG, Shear Stress Transport (SST are used. The article describes selected turbulence models, and considers relationship with wall function.The calculation results allow us to give the values obtained for thermal-hydraulic parameters, to compare selected turbulence models, as well as to show distribution patterns of the coolant temperature, pressure, and velocity at the outlet of the intermediate cooler.Calculations have shown that:- maximum values of primary coolant temperature at the outlet of the heat exchanger surface are encountered in the space between the helical-coil tubes;- higher temperatures of intermediate coolant at the outlet of the coils (in space of helicalcoil tubes are observed for the peripheral row;- primary coolant movement in the inter-tubular space of helical-coil surface is formed as a spiral flow, rather than as a in-line tube bank cross flow.

  4. Numerical investigation on the convective heat transfer in a spiral coil with radiant heating

    Directory of Open Access Journals (Sweden)

    Đorđević Milan Lj.

    2016-01-01

    Full Text Available The objective of this study was to numerically investigate the heat transfer in spiral coil tube in the laminar, transitional, and turbulent flow regimes. The Archimedean spiral coil was exposed to radiant heating and should represent heat absorber of parabolic dish solar concentrator. Specific boundary conditions represent the uniqueness of this study, since the heat flux upon the tube external surfaces varies not only in the circumferential direction, but also in the axial direction. The curvature ratio of spiral coil varies from 0.029 at the flow inlet to 0.234 at the flow outlet, while the heat transfer fluid is water. The 3-D steady-state transport equations were solved using the Reynolds stress turbulence model. Results showed that secondary flows strongly affect the flow and that the heat transfer is strongly asymmetric, with higher values near the outer wall of spiral. Although overall turbulence levels were lower than in a straight pipe, heat transfer rates were larger due to the curvature-induced modifications of the mean flow and temperature fields. [Projekat Ministarstva nauke Republike Srbije, br. 42006

  5. Inductance and resistance measurement method for vessel detection and coil powering in all-surface inductive heating systems composed of outer squircle coils

    Science.gov (United States)

    Kilic, Veli Tayfun; Unal, Emre; Demir, Hilmi Volkan

    2017-05-01

    In this work, we investigate a method proposed for vessel detection and coil powering in an all-surface inductive heating system composed of outer squircle coils. Besides conventional circular coils, coils with different shapes such as outer squircle coils are used for and enable efficient all-surface inductive heating. Validity of the method, which relies on measuring inductance and resistance values of a loaded coil at different frequencies, is experimentally demonstrated for a coil with shape different from conventional circular coil. Simple setup was constructed with a small coil to model an all-surface inductive heating system. Inductance and resistance maps were generated by measuring coil's inductance and resistance values at different frequencies loaded by a plate made of different materials and located at various positions. Results show that in an induction hob for various coil geometries it is possible to detect a vessel's presence, to identify its material type and to specify its position on the hob surface by considering inductance and resistance of the coil measured on at least two different frequencies. The studied method is important in terms of enabling safe, efficient and user flexible heating in an all-surface inductive heating system by automatically detecting the vessel's presence and powering on only the coils that are loaded by the vessel with predetermined current levels.

  6. Research on the Heating of Deicing Fluid in a New Reshaped Coiled Tube

    Directory of Open Access Journals (Sweden)

    Mengli Wu

    2017-01-01

    Full Text Available Aircraft ground deicing operation is significant to ensure civil flight safety in winter. Helically coiled tube is the important heat exchanger in Chinese deicing fluid heating system. In order to improve the deicing efficiency, the research focuses on heat transfer enhancement of deicing fluid in the tube. Based on the field synergy principle, a new reshaped tube (TCHC is designed by ring-rib convex on the inner wall. Deicing fluid is high viscosity ethylene-glycol-based mixture. Because of the power function relation between high viscosity and temperature, viscosity has a negative influence on heat transfer. The number of ring-ribs and inlet velocity are two key parameters to the heat transfer performance. For both water and ethylene glycol, the outlet temperature rises when the number of ring-ribs increases to a certain limit. However, the increasing of velocity reduces heating time, which results in lower outlet temperature. The heating experiment of the original tube is conducted. The error between experiment and simulation is less than 5%. The outlet temperature of TCHC increases by 3.76%. As a result, TCHC efficiently promotes the coordination of velocity and temperature fields by changing the velocity field. TCHC has enhanced heat transfer of high viscosity deicing fluid.

  7. Thermodynamic optimization of a coiled tube heat exchanger under constant wall heat flux condition

    International Nuclear Information System (INIS)

    Satapathy, Ashok K.

    2009-01-01

    In this paper the second law analysis of thermodynamic irreversibilities in a coiled tube heat exchanger has been carried out for both laminar and turbulent flow conditions. The expression for the scaled non-dimensional entropy generation rate for such a system is derived in terms of four dimensionless parameters: Prandtl number, heat exchanger duty parameter, Dean number and coil to tube diameter ratio. It has been observed that for a particular value of Prandtl number, Dean number and duty parameter, there exists an optimum diameter ratio where the entropy generation rate is minimum. It is also found that with increase in Dean number or Reynolds number, the optimum value of the diameter ratio decreases for a particular value of Prandtl number and heat exchanger duty parameter.

  8. Design and fabrication of a radially-fed implosion heating coil

    International Nuclear Information System (INIS)

    Hansborough, L.D.; Dickinson, J.M.; Melton, J.G.; Nunnally, W.C.

    1977-01-01

    A radially-fed implosion heating coil has been designed and fabricated at the Los Alamos Scientific Laboratory. The M arshall coil is a copper-plate-on-epoxy-substrate coil designed to utilize up to 200- kV to produce a 1-T magnetic field in a 20-cm bore with a risetime of no more than 250-ns. The design and fabrication process of this coil and the design of the high-voltage stand for the Marshall coil are discussed

  9. Measurement of heating coil temperature for e-cigarettes with a “top-coil” clearomizer

    Science.gov (United States)

    Wang, Ping; Ito, Kazuhide; Fowles, Jeff; Shusterman, Dennis; Jaques, Peter A.; Kumagai, Kazukiyo

    2018-01-01

    Objectives To determine the effect of applied power settings, coil wetness conditions, and e-liquid compositions on the coil heating temperature for e-cigarettes with a “top-coil” clearomizer, and to make associations of coil conditions with emission of toxic carbonyl compounds by combining results herein with the literature. Methods The coil temperature of a second generation e-cigarette was measured at various applied power levels, coil conditions, and e-liquid compositions, including (1) measurements by thermocouple at three e-liquid fill levels (dry, wet-through-wick, and full-wet), three coil resistances (low, standard, and high), and four voltage settings (3–6 V) for multiple coils using propylene glycol (PG) as a test liquid; (2) measurements by thermocouple at additional degrees of coil wetness for a high resistance coil using PG; and (3) measurements by both thermocouple and infrared (IR) camera for high resistance coils using PG alone and a 1:1 (wt/wt) mixture of PG and glycerol (PG/GL). Results For single point thermocouple measurements with PG, coil temperatures ranged from 322 ‒ 1008°C, 145 ‒ 334°C, and 110 ‒ 185°C under dry, wet-through-wick, and full-wet conditions, respectively, for the total of 13 replaceable coil heads. For conditions measured with both a thermocouple and an IR camera, all thermocouple measurements were between the minimum and maximum across-coil IR camera measurements and equal to 74% ‒ 115% of the across-coil mean, depending on test conditions. The IR camera showed details of the non-uniform temperature distribution across heating coils. The large temperature variations under wet-through-wick conditions may explain the large variations in formaldehyde formation rate reported in the literature for such “top-coil” clearomizers. Conclusions This study established a simple and straight-forward protocol to systematically measure e-cigarette coil heating temperature under dry, wet-through-wick, and full

  10. Thermal performance of a spirally coiled finned tube heat exchanger under wet-surface conditions

    International Nuclear Information System (INIS)

    Wongwises, Somchai; Naphon, Paisarn

    2006-01-01

    This paper is a continuation of the author's previous work on spiral coil heat exchangers. In the present study, the heat transfer characteristics and the performance of a spirally coiled finned tube heat exchanger under wet-surface conditions are theoretically and experimentally investigated. The test section is a spiral-coil heat exchanger which consists of a steel shell and a spirally coiled tube unit. The spiral-coil unit consists of six layers of concentric spirally coiled finned tubes. Each tube is fabricated by bending a 9.6 mm diameter straight copper tube into a spiral-coil of four turns. The innermost and outermost diameters of each spiral-coil are 145.0 and 350.4 mm, respectively. Aluminium crimped spiral fins with thickness of 0.6 mm and outer diameter of 28.4 mm are placed around the tube. The edge of fin at the inner diameter is corrugated. Air and water are used as working fluids in shell side and tube side, respectively. The experiments are done under dehumidifying conditions. A mathematical model based on the conservation of mass and energy is developed to simulate the flow and heat transfer characteristics of working fluids flowing through the heat exchanger. The results obtained from the present model show reasonable agreement with the experimental data

  11. Hybrid coils having an improved heat transfer capability

    NARCIS (Netherlands)

    2008-01-01

    A hybrid coil ( 11 ) employs a wire layer ( 22 ), a wire layer ( 23 ) adjacent the wire layer ( 22 ), and a wire layer ( 24 ) adjacent the wire layer ( 23 ). The hybrid coil ( 11 ) further employs a thermal conductive insulator ( 42 ) physically disposed within a space between the wire layer ( 22 )

  12. An induction heating device using planar coil with high amplitude alternating magnetic fields for magnetic hyperthermia.

    Science.gov (United States)

    Wu, Zuhe; Zhuo, Zihang; Cai, Dongyang; Wu, Jian'an; Wang, Jie; Tang, Jintian

    2015-01-01

    Induction heating devices using the induction coil and magnetic nanoparticles (MNPs) are the way that the magnetic hyperthermia is heading. To facilitate the induction heating of in vivo magnetic nanoparticles in hyperthermia experiments on large animals. An induction heating device using a planar coil was designed with a magnetic field frequency of 328 kHz. The coil's magnetic field distribution and the device's induction heating performance on different concentrations of magnetic nanoparticles were measured. The alternating magnetic field produced in the axis position 165 mm away from the coil center is 40 Gs in amplitude; magnetic nanoparticles with a concentration higher than 80 mg. mL-1 can be heated up rapidly. Our results demonstrate that the device can be applied not only to in vitro and in small animal experiments of magnetic hyperthermia using MNPs, but also in large animal experiments.

  13. Ground Source Heat Pump in Heating System with Electronics Monitoring

    Directory of Open Access Journals (Sweden)

    NEAMŢU Ovidiu

    2013-10-01

    Full Text Available The monitoring system is implemented for a ground coupled heat pump in heating/ system. The borehole heat exchangers – which are 150 m long - are filled with a mixture of water and ethilene glycol calledbrine. Metering and monitoring energy consumption is achieved for: heat pump, circulation pumps, additional electrical heating, hot air ventilation systems, control systems with sensors: analog and smart sensors. Instantaneous values are stored in a local computer.

  14. Insulation and Heat Treatment of Bi-2212 Wire for Wind-and-React Coils

    Energy Technology Data Exchange (ETDEWEB)

    Peter K. F. Hwang

    2007-10-22

    Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2" dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

  15. Insulation and Heat Treatment of Bi-2212 Wires for Wind-and-React Coils

    International Nuclear Information System (INIS)

    Hwang, Peter K.F.

    2007-01-01

    Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2-inch dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

  16. Dynamic Models of Heating and Cooling Coils with One—Dimensional Air Distribution

    Institute of Scientific and Technical Information of China (English)

    WangZijie; G.Krauss

    1993-01-01

    This paper presents the simulation models of the plate-fin,air-to-water(or water vapour) heat exchangers used as air-heating or air-cooling and dehumidifying colis in the HVAC(Heating,Ventilation and AIr-Conditioning)systems.The thermal models are used to calculate the heat exchange between distributing air and coil pipes and outlet temperatures of air and heat or chilled fluid.The aerodynamic models are used to account for the pressure drop of the air crossing the coil tubes,They can also be used to optimize the structres of such coils.The models are based on principal laws of teat and mass conservation and fluid mechanics.They are transparent and easy to use.In our work,a coil is considered as an assembly of numbers of basic elements in which all the state variables are unique.Therefore we can conveniently simulate the coils with different structures and different geometric parameters.Two modular programs TRNSYS(Transient System Simulation)and ESACAP are utilized as supporting softwares which make the programming and simulation greatly simplified.The coil elements and a real coil were simulated.The results were compared with the data offered by the manufacturer(company SOFICA) and also with those obtained using critical methods such as NTU method ,etc.and good agreement is attained.

  17. A 1.5 MJ cryostatic stable superconducting ohmic-heating coil

    International Nuclear Information System (INIS)

    Wang, S.-T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1978-01-01

    As early as FY 1975, ANL had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and proposed a five-year pulsed coil and power supply development program to ERDA. With modest funding made available by ERDA in FY 1977 and the use of substantial equipment inventory at ANL, a small but agressive development program was advanced to the construction of a 1.5 MJ model coil. The principle objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil with a dB/dt ranging from 2 T/s up to 14 T/s. The results of basic cable development and tests will be described. The design and construction of a prototype 1.5 MJ cryostable pulsed coil and its nonmetallic cryostat will be presented. (author)

  18. Crawl space assisted heat pump. [using stored ground heat

    Science.gov (United States)

    Ternes, M. P.

    1980-01-01

    A variety of experiments and simulations, currently being designed or underway, to determine the feasibility of conditioning the source air of an air to air heat pump using stored ground heat or cool to produce higher seasonal COP's and net energy savings are discussed. The ground would condition ambient air as it is drawn through the crawl space of a house. Tests designed to evaluate the feasibility of the concept, to determine the amount of heat or cool available from the ground, to study the effect of the system on the heating and cooling loads of the house, to study possible mechanisms which could enhance heat flow through the ground, and to determine if diurnal temperature swings are necessary to achieve successful system performance are described.

  19. Exergy Analysis of a Ground-Coupled Heat Pump Heating System with Different Terminals

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2015-04-01

    Full Text Available In order to evaluate and improve the performance of a ground-coupled heat pump (GCHP heating system with radiant floors as terminals, an exergy analysis based on test results is performed in this study. The system is divided into four subsystems, and the exergy loss and exergy efficiency of each subsystem are calculated using the expressions derived based on exergy balance equations. The average values of the measured parameters are used for the exergy analysis. The analysis results show that the two largest exergy losses occur in the heat pump and terminals, with losses of 55.3% and 22.06%, respectively, and the lowest exergy efficiency occurs in the ground heat exchange system. Therefore, GCHP system designers should pay close attention to the selection of heat pumps and terminals, especially in the design of ground heat exchange systems. Compared with the scenario system in which fan coil units (FCUs are substituted for the radiant floors, the adoption of radiant floors can result in a decrease of 12% in heating load, an increase of 3.24% in exergy efficiency of terminals and an increase of 1.18% in total exergy efficiency of the system. The results may point out the direction and ways of optimizing GCHP systems.

  20. Real-time protection of the Ohmic heating coil force limits in DIII-D

    International Nuclear Information System (INIS)

    Broesch, J.D.; Scoville, J.T.; Hyatt, A.W.; Coon, R.M.

    1997-11-01

    The maximum safe operating limits of the DIII-D tokamak are determined by the force produced in the ohmic heating coil and the toroidal field coil during a plasma pulse. This force is directly proportional to the product of the current in the coils. Historically, the current limits for each coil were set statically before each pulse without regard for the time varying nature of the currents. In order to allow the full time-dependent capability of the ohmic coil to be used, a system was developed for monitoring the product of the currents dynamically and making appropriate adjustments in real time. This paper discusses the purpose, implementation, and results of this work

  1. Boiling heat transfer and dryout in helically coiled tubes under different pressure conditions

    International Nuclear Information System (INIS)

    Chung, Young-Jong; Bae, Kyoo-Hwan; Kim, Keung Koo; Lee, Won-Jae

    2014-01-01

    Highlights: • Heat transfer characteristics and dryout for helically coiled tube are performed. • A boiling heat transfer tends to increase with a pressure increase. • Dryout occurs at high quality test conditions investigated. • Steiner–Taborek’s correlation is predicted well based on the experimental results. - Abstract: A helically coiled once-through steam generator has been used widely during the past several decades for small nuclear power reactors. The heat transfer characteristics and dryout conditions are important to optimal design a helically coiled steam generator. Various experiments with the helically coiled tubes are performed to investigate the heat transfer characteristics and occurrence condition of a dryout. For the investigated experimental conditions, Steiner–Taborek’s correlation is predicted reasonably based on the experimental results. The pressure effect is important for the boiling heat transfer correlation. A boiling heat transfer tends to increase with a pressure increase. However, it is not affected by the pressure change at a low power and low mass flow rate. Dryout occurs at high quality test conditions investigated because a liquid film on the wall exists owing to a centrifugal force of the helical coil

  2. Thermoeconomic Optimization of a Combined Heating and Humidification Coil for HVAC Systems

    Science.gov (United States)

    Teodoros, Liliana; Andresen, Bjarne

    2016-07-01

    The total cost of ownership is calculated for a combined heating and humidification coil of an air-handling unit taking into account investment and operation costs simultaneously. This total cost represents the optimization function for which the minimum is sought. The parameters for the cost dependencies are the physical dimensions of the coil: length, width and height. The term "coil" is used generically since in this setup it generates heating as well as humidification in a single unit. The first part of the paper deals with the constructive optimization and finds the relationship between the dimensions for a minimum cost. The second part of the paper takes the results of the constructive optimization further and, based on the data derived in our previous papers, analyzes the minimum total cost for the humidification coil while balancing the amount of water used to humidify the air and modify its temperature.

  3. Cooperative heat transfer and ground coupled storage system

    Science.gov (United States)

    Metz, P.D.

    A cooperative heat transfer and ground coupled storage system wherein collected solar heat energy is ground stored and permitted to radiate into the adjacent ground for storage therein over an extended period of time when such heat energy is seasonally maximally available. Thereafter, when said heat energy is seasonally minimally available and has propagated through the adjacent ground a substantial distance, the stored heat energy may be retrieved by a circumferentially arranged heat transfer means having a high rate of heat transfer.

  4. Experimental analysis of direct-expansion ground-coupled heat pump systems

    Science.gov (United States)

    Mei, V. C.; Baxter, V. D.

    1991-09-01

    Direct-expansion ground-coil-coupled (DXGC) heat pump systems have certain energy efficiency advantages over conventional ground-coupled heat pump (GCHP) systems. Principal among these advantages are that the secondary heat transfer fluid heat exchanger and circulating pump are eliminated. While the DXGC concept can produce higher efficiencies, it also produces more system design and environmental problems (e.g., compressor starting, oil return, possible ground pollution, and more refrigerant charging). Furthermore, general design guidelines for DXGC systems are not well documented. A two-pronged approach was adopted for this study: (1) a literature survey, and (2) a laboratory study of a DXGC heat pump system with R-22 as the refrigerant, for both heating and cooling mode tests done in parallel and series tube connections. The results of each task are described in this paper. A set of general design guidelines was derived from the test results and is also presented.

  5. Heat dissipation research on the water-cooling channel of HL-2M in-vessel coils

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, J., E-mail: jiangjiaming@swip.ac.cn; Liu, Y.; Chen, Q.; Ji, X.Q.

    2017-04-15

    Highlights: • The joule heat of in-vessel coils is very difficult to dissipate inside HL-2M vacuum vessel. • Heat dissipation model of the coil includes the joule heat model, the heat conduction model and the heat transfer model. • The CFD analysis has been done for the coil-water cooling, with comparison with the date of theoretical analysis and experiment. • The result shows water-cooling channel is good for the joule heat transfer and taken away. - Abstract: HL-2M in-vessel coils are positioned in high vacuum circumstance, and they will generate joule heat when they carry 15 kA electrical current, but joule heat is very difficult to dissipate in vacuum, so a hollow cable with 8 mm inner diameter is design as water-cooling channel for heat convection. By using the methods of the theoretical derivation, together with CFD numeric simulation method and the experiment of the heat transfer, the water channel of HL-2M in-vessel coils has been studied, and the temperature of HL-2M in-vessel coils under different cooling water flow rates is obtained and acceptable. Simultaneously, the external cooling water supply system parameters for the water-cooling channel of the coils are estimated. Three methods’ results are in good agreement; the theoretical model is verified and could be popularized for predicting the temperature rise of HL-2M in-vessel coils.

  6. Experimental analysis for heat transfer of nanofluid with wire coil turbulators in a concentric tube heat exchanger

    Science.gov (United States)

    Akyürek, Eda Feyza; Geliş, Kadir; Şahin, Bayram; Manay, Eyüphan

    2018-06-01

    Nanofluids are a novel class of heat transfer suspensions of metallic or nonmetallic nanopowders with a size of less than 100 nm in base fluids and they can increase heat transfer potential of the base fluids in various applications. In the last decade, nanofluids have become an intensive research topic because of their improved thermal properties and possible heat transfer applications. For comparison, an experiment using water as the working fluid in the heat exchanger without wire coils was also performed. Turbulent forced convection heat transfer and pressure drop characteristics of Al2O3-water nanofluids in a concentric tube heat exchanger with and without wire coil turbulators were experimentally investigated in this research. Experiments effected particle volume concentrations of 0.4-0.8 to 1.2-1.6 vol% in the Reynolds number range from 4000 to 20,000. Two turbulators with the pitches of 25 mm and 39 mm were used. The average Nusselt number increased with increasing the Reynolds number and particle concentrations. Moreover, the pressure drop of the Al2O3-water nanofluid showed nearly equal to that of pure water at the same Reynolds number range. As a result, nanofluids with lower particle concentrations did not show an important influence on pressure drop change. Nonetheless, when the wire coils used in the heat exchanger, it increased pressure drop as well as the heat transfer coefficient.

  7. Effect of γ-Al2O3/water nanofluid on the thermal performance of shell and coil heat exchanger with different coil torsions

    Science.gov (United States)

    Elshazly, K. M.; Sakr, R. Y.; Ali, R. K.; Salem, M. R.

    2017-06-01

    This work investigated experimentally the thermal performance of shell and coil heat exchanger with different coil torsions (λ) for γ-Al2O3/water nanofluid flow. Five helically coiled tube (HCT) with 0.0442 ≤ λ ≤ 0.1348 were tested within turbulent flow regime. The average size of γ-Al2O3 particles is 40 nm and volume concentration (φ) is varied from 0 to 2%. Results showed that reducing coil torsion enhances the heat transfer rate and increases HCT-friction factor (fc). Also, it is noticed that HCT average Nusselt number (Nut) and fc of nanofluids increase with increasing γ-Al2O3 volume concentration. The thermal performance index, TPI = (ht,nf/ht,bf)/(ΔPc,nf/ΔPc,bf). increases with increasing nanoparticles concentration, coil torsion, HCT-side inlet temperature and nanofluid flow rate. Over the studied range of HCT-Reynolds number, the average value of TPI is of 1.34 and 2.24 at φ = 0.5% and φ = 2%, respectively. The average value of TPI is of 1.64 at λ = 0.0442 while its average value at λ = 0.1348 is of 2.01. One of the main contributions is to provide heat equipments designers with Nut and fc correlations for practical configurations shell and coil heat exchangers with a wide range of nanofluid concentration.

  8. Geothermal energy. Ground source heat pumps

    International Nuclear Information System (INIS)

    2009-01-01

    Geothermal energy can be harnessed in 2 different ways: electricity or heat generation. The combined net electrical geothermal power of the European Union countries reached 719.3 MWe in 2008 (4.8 MW up on 2007) for 868.1 MWe of installed capacity. Gross electrical production contracted slightly in 2008 (down 1% on the 2007 level) and stood at 5809.5 GWh in 2008. Italy has a overwhelming position with a production of 5520.3 GWh. Geothermal heat production concerning aquifers whose temperature is 30-150 C. degrees generally at a depth of 1-3 km is called low- and medium-enthalpy energy. 18 of the 27 EU members use low- and medium-enthalpy energy totaling 2560.0 MWth of installed capacity that yielded 689.2 ktoe in 2008 and 3 countries Hungary, Italy and France totaling 480.3 ktoe. Very low-enthalpy energy concerns the exploitation of shallow geothermal resources using geothermal heat pumps. In 2008, 114452 ground heat pumps were sold in Europe. At the end of 2008, the installed capacity was 8955.4 MWth (16.5% up on 2007 level, it represented 785206 pumps. Over one million ground heat pumps are expected to be operating in 2010 in Europe. (A.C.)

  9. Dryout in sodium-heated helically-coiled steam generator tubes

    International Nuclear Information System (INIS)

    Tomita, Y.; Kosugi, T.; Kubota, J.; Nakajima, K.; Tsuchiya, T.

    1984-01-01

    Experimental research on the dryout phenomenon in sodium heated, helically coiled steam generator tubes was carried out. The fluctuation of the tube wall temperature caused by dryout was measured with thermocouples installed in the center of the tube wall. Empirical correlations of dryout quality were developed as functions of critical heat flux, water mass velocity and saturation pressure. These correlations confirmed that the design criterion of the MONJU steam generator was reasonable. (author)

  10. Study of a Coil Heat Exchanger with an Ice Storage System

    Directory of Open Access Journals (Sweden)

    Yan Li

    2017-12-01

    Full Text Available In this study, a coil heat exchanger with an ice storage system is analyzed by theoretical analysis, numerical analysis, and experimental analysis. The dynamic characteristics of ice thickness variation is studied by means of unstable heat conduction theory in cylindrical coordinates, and the change rule of the ice layer thickness is obtained. The computational fluid dynamics method is employed to simulate the flow field and ice melting process of the coil heat exchanger. The effect of the agitator height on the flow characteristics and heat transfer characteristics is investigated. The numerical results show that the turbulence intensity of the fluid near the wall of the heat exchanger is the largest with an agitator height of 80 mm. Furthermore, the process of ice melting is analyzed. The ice on the outer side of the evaporator tube close to the container wall melts faster than the inner side and this agrees well with the experimental result. The experimental study on the process of the operational period and deicing of the coil heat exchanger is conducted and the temperature variation curves are obtained by the arrangement of thermocouples. It is found that the temperature of the evaporating tube increases with increasing height in the process of ice storage.

  11. Performance Analysis of Slinky Horizontal Ground Heat Exchangers for a Ground Source Heat Pump System

    Directory of Open Access Journals (Sweden)

    Md. Hasan Ali

    2017-10-01

    Full Text Available This paper highlights the thermal performance of reclined (parallel to ground surface and standing (perpendicular to ground surface slinky horizontal ground heat exchangers (HGHEs with different water mass flow rates in the heating mode of continuous and intermittent operations. A copper tube with an outer surface protected with low-density polyethylene was selected as the tube material of the ground heat exchanger. Effects on ground temperature around the reclined slinky HGHE due to heat extraction and the effect of variation of ground temperatures on reclined HGHE performance are discussed. A higher heat exchange rate was experienced in standing HGHE than in reclined HGHE. The standing HGHE was affected by deeper ground temperature and also a greater amount of backfilled sand in standing HGHE (4.20 m3 than reclined HGHE (1.58 m3, which has higher thermal conductivity than site soil. For mass flow rate of 1 L/min with inlet water temperature 7 °C, the 4-day average heat extraction rates increased 45.3% and 127.3%, respectively, when the initial average ground temperatures at 1.5 m depth around reclined HGHE increased from 10.4 °C to 11.7 °C and 10.4 °C to 13.7 °C. In the case of intermittent operation, which boosted the thermal performance, a short time interval of intermittent operation is better than a long time interval of intermittent operation. Furthermore, from the viewpoint of power consumption by the circulating pump, the intermittent operation is more efficient than continuous operation.

  12. Turbulent convective heat transfer of methane at supercritical pressure in a helical coiled tube

    Science.gov (United States)

    Wang, Chenggang; Sun, Baokun; Lin, Wei; He, Fan; You, Yingqiang; Yu, Jiuyang

    2018-02-01

    The heat transfer of methane at supercritical pressure in a helically coiled tube was numerically investigated using the Reynolds Stress Model under constant wall temperature. The effects of mass flux ( G), inlet pressure ( P in) and buoyancy force on the heat transfer behaviors were discussed in detail. Results show that the light fluid with higher temperature appears near the inner wall of the helically coiled tube. When the bulk temperature is less than or approach to the pseudocritical temperature ( T pc ), the combined effects of buoyancy force and centrifugal force make heavy fluid with lower temperature appear near the outer-right of the helically coiled tube. Beyond the T pc , the heavy fluid with lower temperature moves from the outer-right region to the outer region owing to the centrifugal force. The buoyancy force caused by density variation, which can be characterized by Gr/ Re 2 and Gr/ Re 2.7, enhances the heat transfer coefficient ( h) when the bulk temperature is less than or near the T pc , and the h experiences oscillation due to the buoyancy force. The oscillation is reduced progressively with the increase of G. Moreover, h reaches its peak value near the T pc . Higher G could improve the heat transfer performance in the whole temperature range. The peak value of h depends on P in. A new correlation was proposed for methane at supercritical pressure convective heat transfer in the helical tube, which shows a good agreement with the present simulated results.

  13. Conceptual designs of 50 kA 20 MJ superconducting ohmic heating coils

    International Nuclear Information System (INIS)

    Singh, S.K.; Murphy, J.H.; Janocko, M.A.; Haller, H.E.; Litz, D.C.; Eckels, P.W.; Rogers, J.D.; Thullen, P.

    1979-01-01

    Two designs of 20 Mj superconducting coils are described which were developed to demonstrate the feasibility of an ohmic heating system. NbTi and Nb;sub 3;Sn superconductors were considered for both 7 tesla and 9 tesla maximum fields. Cabled and braided conductors were investigated and the braided conductor is identified as the best alternative due to its high operating current densities and because of its porosity. The coils are designed to be cryostable for bipolar operation from +7 tesla to -7 tesla and from +9 tesla to -9 tesla maximum fields within 1 sec. The structural design addresses the distribution of structure and structural materials used in the pulsed field environment. Immersion cooled (pool boil) and forced flow cooled coils are described. 2 refs

  14. Heat recovery from ground below the solar pond

    NARCIS (Netherlands)

    Ganguly, S.; Date, Abhijit; Akbarzadeh, Aliakbar

    2017-01-01

    The method of heat recovery from the ground below solar ponds is investigated in the present brief note. Solar ponds lose considerable amount of heat from its bottom to the ground due to temperature gradient between them. This waste heat from ground, which is at different temperature at different

  15. Acceleration of calculation of nuclear heating distributions in ITER toroidal field coils using hybrid Monte Carlo/deterministic techniques

    International Nuclear Information System (INIS)

    Ibrahim, Ahmad M.; Polunovskiy, Eduard; Loughlin, Michael J.; Grove, Robert E.; Sawan, Mohamed E.

    2016-01-01

    Highlights: • Assess the detailed distribution of the nuclear heating among the components of the ITER toroidal field coils. • Utilize the FW-CADIS method to dramatically accelerate the calculation of detailed nuclear analysis. • Compare the efficiency and reliability of the FW-CADIS method and the MCNP weight window generator. - Abstract: Because the superconductivity of the ITER toroidal field coils (TFC) must be protected against local overheating, detailed spatial distribution of the TFC nuclear heating is needed to assess the acceptability of the designs of the blanket, vacuum vessel (VV), and VV thermal shield. Accurate Monte Carlo calculations of the distributions of the TFC nuclear heating are challenged by the small volumes of the tally segmentations and by the thick layers of shielding provided by the blanket and VV. To speed up the MCNP calculation of the nuclear heating distribution in different segments of the coil casing, ground insulation, and winding packs of the ITER TFC, the ITER Organization (IO) used the MCNP weight window generator (WWG). The maximum relative uncertainty of the tallies in this calculation was 82.7%. In this work, this MCNP calculation was repeated using variance reduction parameters generated by the Oak Ridge National Laboratory AutomateD VAriaNce reducTion Generator (ADVANTG) code and both MCNP calculations were compared in terms of computational efficiency and reliability. Even though the ADVANTG MCNP calculation used less than one-sixth of the computational resources of the IO calculation, the relative uncertainties of all the tallies in the ADVANTG MCNP calculation were less than 6.1%. The nuclear heating results of the two calculations were significantly different by factors between 1.5 and 2.3 in some of the segments of the furthest winding pack turn from the plasma neutron source. Even though the nuclear heating in this turn may not affect the ITER design because it is much smaller than the nuclear heating in the

  16. Acceleration of calculation of nuclear heating distributions in ITER toroidal field coils using hybrid Monte Carlo/deterministic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Ahmad M., E-mail: ibrahimam@ornl.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Polunovskiy, Eduard; Loughlin, Michael J. [ITER Organization, Route de Vinon Sur Verdon, 13067 St. Paul Lez Durance (France); Grove, Robert E. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Sawan, Mohamed E. [University of Wisconsin-Madison, 1500 Engineering Dr., Madison, WI 53706 (United States)

    2016-11-01

    Highlights: • Assess the detailed distribution of the nuclear heating among the components of the ITER toroidal field coils. • Utilize the FW-CADIS method to dramatically accelerate the calculation of detailed nuclear analysis. • Compare the efficiency and reliability of the FW-CADIS method and the MCNP weight window generator. - Abstract: Because the superconductivity of the ITER toroidal field coils (TFC) must be protected against local overheating, detailed spatial distribution of the TFC nuclear heating is needed to assess the acceptability of the designs of the blanket, vacuum vessel (VV), and VV thermal shield. Accurate Monte Carlo calculations of the distributions of the TFC nuclear heating are challenged by the small volumes of the tally segmentations and by the thick layers of shielding provided by the blanket and VV. To speed up the MCNP calculation of the nuclear heating distribution in different segments of the coil casing, ground insulation, and winding packs of the ITER TFC, the ITER Organization (IO) used the MCNP weight window generator (WWG). The maximum relative uncertainty of the tallies in this calculation was 82.7%. In this work, this MCNP calculation was repeated using variance reduction parameters generated by the Oak Ridge National Laboratory AutomateD VAriaNce reducTion Generator (ADVANTG) code and both MCNP calculations were compared in terms of computational efficiency and reliability. Even though the ADVANTG MCNP calculation used less than one-sixth of the computational resources of the IO calculation, the relative uncertainties of all the tallies in the ADVANTG MCNP calculation were less than 6.1%. The nuclear heating results of the two calculations were significantly different by factors between 1.5 and 2.3 in some of the segments of the furthest winding pack turn from the plasma neutron source. Even though the nuclear heating in this turn may not affect the ITER design because it is much smaller than the nuclear heating in the

  17. Numerical study on turbulent heat transfer and pressure drop of nanofluid in coiled tube-in-tube heat exchangers

    International Nuclear Information System (INIS)

    Aly, Wael I.A.

    2014-01-01

    Highlights: • The performance of helically coiled tube heat exchanger using nanofluid is modeled. • The 3D turbulent flow and conjugate heat transfer of CTITHE are solved using FVM. • The effects of nanoparticle concentration and curvature ratio are investigated. • The Gnielinski correlation for Nu for turbulent flow in helical tubes can be used for water-based Al 2 O 3 nanofluid. - Abstract: A computational fluid dynamics (CFD) study has been carried out to study the heat transfer and pressure drop characteristics of water-based Al 2 O 3 nanofluid flowing inside coiled tube-in-tube heat exchangers. The 3D realizable k–ε turbulent model with enhanced wall treatment was used. Temperature dependent thermophysical properties of nanofluid and water were used and heat exchangers were analyzed considering conjugate heat transfer from hot fluid in the inner-coiled tube to cold fluid in the annulus region. The overall performance of the tested heat exchangers was assessed based on the thermo-hydrodynamic performance index. Design parameters were in the range of; nanoparticles volume concentrations 0.5%, 1.0% and 2.0%, coil diameters 0.18, 0.24 and 0.30 m, inner tube and annulus sides flow rates from 2 to 5 LPM and 10 to 25 LPM, respectively. Nanofluid flows inside inner tube side or annular side. The results obtained showed a different behavior depending on the parameter selected for the comparison with the base fluid. Moreover, when compared at the same Re or Dn, the heat transfer coefficient increases by increasing the coil diameter and nanoparticles volume concentration. Also, the friction factor increases with the increase in curvature ratio and pressure drop penalty is negligible with increasing the nanoparticles volume concentration. Conventional correlations for predicting average heat transfer and friction factor in turbulent flow regime such as Gnielinski correlation and Mishra and Gupta correlation, respectively, for helical tubes are also valid for

  18. Confinement and heating in modular and continuous coil stellarators

    International Nuclear Information System (INIS)

    Anderson, D.T.; Anderson, F.S.B.; Bonomo, R.L.

    1983-01-01

    Major efforts on the Proto-Cleo stellarator have focused on ICRH of a net current-free plasma, measurements of plasma secondary currents, RF heating by externally induced magnetic reconnection through the formation and destruction of an internal separatrix, and RF current drive experiments. Efforts on the Proto-Cleo torsatron have focused on electron heat conduction. A modular stellarator has been designed and is under fabrication at the University of Wisconsin. The Interchangeable Module Stellarator (IMS) is designed to approximate closely the magnetic properties of the existing Proto-Cleo stellarator as much as possible. Monte-Carlo transport calculations have been made in flux coordinates using model fields patterned after magnetic fields in Proto-Cleo and IMS. Plasma simulation techniques using a 2.5-dimensional particle-in-cell method have been utilized in a numerical search for the bootstrap current. A current is found which is proportional to temperature and density gradients but is independent of poloidal field. The behaviour of charged particles moving in a stellarator under the influence of a steady magnetic field is analysed in terms of the Hamiltonian of the moving particle and the technique of repeated canonical transformations to identify possible adiabatic invariants and drift motions. An improved theory of collisionless particle motion in stellarators has been developed for a family of stellarator configurations. The broad range of configurations encompassed by this family permits an understanding of the differences in numerically observed transport coefficients. Two procedures have been developed to calculate the bootstrap current in non-axisymmetric stellarators. In fully toroidal stellarators the flows and consequent bootstrap current are reduced from their axisymmetric values by a factor of order l slash-l/m in the Pfirsch-Schlueter regime. (author)

  19. Seismic analysis of a helical coil type heat exchanger

    International Nuclear Information System (INIS)

    Nishiguchi, I.; Baba, O.; Yatabe, H.

    1984-01-01

    The intermediate heat exchanger (IHX) which forms the reactor coolant pressure boundary is one of the most important components of the Multi-purpose Experimental Very High Temperature Gas-cooled Reactor (ex. VHTR) under development at Japan Atomic Energy Research Institute. This paper presents the results of the finite element modeling, eigenvalue analysis and dynamic response analysis of the IHX. For the modeling, the structure of the IHX was separated into a helical tube bundle, inner and outer vessels, and a center pipe. The eigenvalue analysis was made for each structure with a detailed three-dimensional finite element model. Then the simplified model of the whole structure of the IHX was constructed using the result of the eigenvalue analysis. A dynamic response analysis was made for the simplified model with and without stoppers of the helical tube bundle supports and the center pipe. The effect of stoppers on the behavior of the center pipe, the helical tube, and the connecting tube is discussed. (author)

  20. Productivity Enhancement of Solar Still with PV Powered Heating Coil and Chamber Step-Wise Basin

    Directory of Open Access Journals (Sweden)

    Salah Abdallah

    2018-03-01

    Full Text Available There is a strong need to improve the productivity of single slope solar still. PV generator powered electrical heater and chamber step-wise design were introduced to the conventional solar still. An experimental study was performed to investigate the effect of adding the above mentioned modifications on the output parameters of the modified solar still. The inclusion of PV-powered heating coil and chamber step-wise design enhanced the productivity of distiller by up to 1098%.

  1. Superconductor design and loss analysis for a 20 MJ induction heating coil

    International Nuclear Information System (INIS)

    Walker, M.S.; Declercq, J.G.; Zeitlin, B.A.

    1980-01-01

    The design of a 50 k Ampere conductor for use in a 20 MJ Induction Heating Coil is described. The conductor is a wide flat cable of 36 subcables, each of which contains six NbTi strands around a stainless steel core strand. The 2.04 mm (0.080'') diameter monolithic strands allow bubble clearing for cryostable operation at a pool boiling heat transfer from the unoccluded strand surface of 0.26 Watts/cm 2 . A thin, tough polyester amide-imide (Westinghouse Omega) insulation provides a rugged coating that will resist flaking and chipping during the cabling and compaction operations and provide (1) a reliable adherent surface for enhanced heat transfer, and (2) a low voltage standoff preventing interstrand coupling losses. The strands are uniquely configured using CuNi elements to provide low ac losses with NbTi filaments in an all-copper matrix. AC losses are expected to be approximately 0.3% of 20 MJ for a -7.5 T to 7.5 T one-second 1/2-cosinusoidal bipolar operation in a 20 MJ coil. They will be approximately 0.1% of 100 MJ for 1.8 second -8 T and +8 T ramped operation in a 100 MJ coil. The design is firmly based on the results of tests performed on prototype strands and subcables

  2. Optimal Ground Source Heat Pump System Design

    Energy Technology Data Exchange (ETDEWEB)

    Ozbek, Metin [Environ Holdings Inc., Princeton, NJ (United States); Yavuzturk, Cy [Univ. of Hartford, West Hartford, CT (United States); Pinder, George [Univ. of Vermont, Burlington, VT (United States)

    2015-04-01

    Despite the facts that GSHPs first gained popularity as early as the 1940’s and they can achieve 30 to 60 percent in energy savings and carbon emission reductions relative to conventional HVAC systems, the use of geothermal energy in the U.S. has been less than 1 percent of the total energy consumption. The key barriers preventing this technically-mature technology from reaching its full commercial potential have been its high installation cost and limited consumer knowledge and trust in GSHP systems to deliver the technology in a cost-effective manner in the market place. Led by ENVIRON, with support from University Hartford and University of Vermont, the team developed and tested a software-based a decision making tool (‘OptGSHP’) for the least-cost design of ground-source heat pump (‘GSHP’) systems. OptGSHP combines state of the art optimization algorithms with GSHP-specific HVAC and groundwater flow and heat transport simulation. The particular strength of OptGSHP is in integrating heat transport due to groundwater flow into the design, which most of the GSHP designs do not get credit for and therefore are overdesigned.

  3. Effects of design parameters and puff topography on heating coil temperature and mainstream aerosols in electronic cigarettes

    Science.gov (United States)

    Zhao, Tongke; Shu, Shi; Guo, Qiuju; Zhu, Yifang

    2016-06-01

    Emissions from electronic cigarettes (ECs) may contribute to both indoor and outdoor air pollution and the number of users is increasing rapidly. ECs operate based on the evaporation of e-liquid by a high-temperature heating coil. Both puff topography and design parameters can affect this evaporation process. In this study, both mainstream aerosols and heating coil temperature were measured concurrently to study the effects of design parameters and puff topography. The heating coil temperatures and mainstream aerosols varied over a wide range across different brands and within same brand. The peak heating coil temperature and the count median diameter (CMD) of EC aerosols increased with a longer puff duration and a lower puff flow rate. The particle number concentration was positively associated with the puff duration and puff flow rate. These results provide a better understanding of how EC emissions are affected by design parameters and puff topography and emphasize the urgent need to better regulate EC products.

  4. Determination of Ground Heat Exchangers Temperature Field in Geothermal Heat Pumps

    Science.gov (United States)

    Zhurmilova, I.; Shtym, A.

    2017-11-01

    For the heating and cooling supply of buildings and constructions geothermal heat pumps using low-potential ground energy are applied by means of ground exchangers. The process of heat transfer in a system of ground exchangers is a phenomenon of complex heat transfer. The paper presents a mathematical modeling of heat exchange processes, the temperature fields are built which are necessary for the determination of the ground array that ensures an adequate supply of low potential energy excluding the freezing of soil around the pipes in the ground heat exchangers and guaranteeing a reliable operation of geothermal heat pumps.

  5. Heat treatment control of Bi-2212 coils: I. Unravelling the complex dependence of the critical current density of Bi-2212 wires on heat treatment

    Science.gov (United States)

    Shen, Tengming; Li, Pei; Ye, Liyang

    2018-01-01

    A robust and reliable heat treatment is crucial for developing superconducting magnets from several superconductors especially Bi-2212. An improper heat treatment may significantly reduce the critical current density Jc of a Bi-2212 superconducting coil, even to zero, since the Jc of Bi-2212 wires is sensitive to parameters of its heat treatment (partial melt processing). To provide an essential database for heat treating Bi-2212 coils, the dependence of Jc on heat treatment is studied systematically in 11 industrial Bi-2212 wires, revealing several common traits shared between these wires and outlier behaviors. The dependence of the Jc of Bi-2212 on heat treatment is rather complex, with many processing parameters affecting Jc, including the peak processing temperature Tp, the time at the peak temperature tp, the time in the melt tmelt, the rate at which Bi-2212 melt is initially cooled CR1, the rate at which the solidification of Bi-2212 melt occurs CR2, and the temperature Tq at which the cooling rate switches from CR1 to CR2. The role of these parameters is analyzed and clarified, in the perspective of heat treating a coil. Practical advices on heat treatment design are given. The ability of a Bi-2212 coil to follow the prescribed recipe decreases with increasing coil sizes. The size of a coil that can be properly heat treated is determined.

  6. Ground-source heat pump barometer

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    In Europe the ground-source heat pump market contracted for the second year running by 2.9% between 2009 and 2010. Around 103.000 units were sold in 2010, taking the number of installed units over one million. The 3 European countries with the most sales are Sweden (31953 units, +16%), Germany (25516 units, -13%) and France (12250 units, -21%). The drop in sales is generally due to market contraction on the current recession but some specificities exist: for instance the insufficient training of the installers has led to under-performance and to a bad image of this energy in France. The Swedish and German manufacturers are in a very strong position and are increasing their market share in the main European markets. (A.C.)

  7. Domestic Hot Water Production with Ground Source Heat Pump in Apartment Buildings

    Directory of Open Access Journals (Sweden)

    Jukka Yrjölä

    2015-08-01

    Full Text Available Producing domestic hot water (DHW with a ground source heat pump (GSHP is challenging due to the high temperature (HT of DHW. There are many studies proving the better performance of cascade heat pumps compared to single-stage heat pumps when the difference between the condensing and the evaporation temperature is large. In this system approach study, different GSHP arrangements are described and computationally compared. A two-stage heat pump arrangement is introduced in which water tanks of the heating system are utilized for warming up the DHW in two stages. It is shown that the electricity consumption with this two-stage system is approximately 31% less than with the single-stage heat pump and 12% less than with the cascade system. Further, both low temperature (LT and HT heat pumps can run alone, which is not common in cascade or other two-stage heat pumps. This is advantageous because the high loads of the space heating and DHW production are not simultaneous. Proper insulation of the DHW and recirculation pipe network is essential, and drying towel rails or other heating coils should be avoided when aiming for a high efficiency. The refrigerants in the calculations are R407C for the LT heat pump and R134a for the HT heat pump. Investment costs are excluded from calculations.

  8. CFD analysis of the two-phase bubbly flow characteristics in helically coiled rectangular and circular tube heat exchangers

    Directory of Open Access Journals (Sweden)

    Hussain Alamin

    2016-01-01

    Full Text Available Due to their ease of manufacture, high heat transfer efficiency and compact design, helically coiled heat exchangers are increasingly being adopted in a number of industries. The higher heat transfer efficiency over straight pipes is due to the secondary flow that develops as a result of the centrifugal force. In spite of the widespread use of helically coiled heat exchangers, and the presence of bubbly two-phase flow in a number of systems, very few studies have investigated the resultant flow characteristics. This paper will therefore present the results of CFD simulations for the two-phase bubbly flow in helically coiled heat exchangers as a function of the volumetric void fraction and the tube cross-section design. The CFD results are compared to the scarce flow visualisation experimental results available in the open literature.

  9. CFD analysis of the two-phase bubbly flow characteristics in helically coiled rectangular and circular tube heat exchangers

    Science.gov (United States)

    Hussain, Alamin; Fsadni, Andrew M.

    2016-03-01

    Due to their ease of manufacture, high heat transfer efficiency and compact design, helically coiled heat exchangers are increasingly being adopted in a number of industries. The higher heat transfer efficiency over straight pipes is due to the secondary flow that develops as a result of the centrifugal force. In spite of the widespread use of helically coiled heat exchangers, and the presence of bubbly two-phase flow in a number of systems, very few studies have investigated the resultant flow characteristics. This paper will therefore present the results of CFD simulations for the two-phase bubbly flow in helically coiled heat exchangers as a function of the volumetric void fraction and the tube cross-section design. The CFD results are compared to the scarce flow visualisation experimental results available in the open literature.

  10. Estimate of thermoelastic heat production from superconducting composites in pulsed poloidal coil systems

    International Nuclear Information System (INIS)

    Ballou, J.K.; Gray, W.H.

    1976-01-01

    In the design of the cryogenic system and superconducting magnets for the poloidal field system in a tokamak, it is important to have an accurate estimate of the heat produced in superconducting magnets as a result of rapidly changing magnetic fields. A computer code, PLASS (Pulsed Losses in Axisymmetric Superconducting Solenoids), was written to estimate the contributions to the heat production from superconductor hysteresis losses, superconductor coupling losses, stabilizing material eddy current losses, and structural material eddy current losses. Recently, it has been shown that thermoelastic dissipation in superconducting composites can contribute as much to heat production as the other loss mechanisms mentioned above. A modification of PLASS which takes into consideration thermoelastic dissipation in superconducting composites is discussed. A comparison between superconductor thermoelastic dissipation and the other superconductor loss mechanisms is presented in terms of the poloidal coil system of the ORNL Experimental Power Reactor design

  11. High temperature technological heat exchangers and steam generators with helical coil assembly tube bundle

    International Nuclear Information System (INIS)

    Korotaev, O.J.; Mizonov, N.V.; Nikolaevsky, V.B.; Nazarov, E.K.

    1990-01-01

    Analysis of thermal hydraulics characteristics of nuclear steam generators with different tube bundle arrangements and waste heat boilers for ammonia production units was performed on the basis of operating experience results and research and development data. The present report involves the obtained information. The estimations of steam generator performances and repair-ability are given. The significant temperature profile of the primary and secondary coolant flows are attributed to all steam generator designs. The intermediate mixing is found to be an effective means of temperature profile overcoming. At present the only means to provide an effective mixing in heat exchangers of the following types: straight tubes, field tubes, platen tubes and multibank helical coil tubes (with complicated bend distribution along their length) are section arrangements in series in conjunction with forced and natural mixing in connecting lines. Development of the unificated system from mini helical coil assemblies allows to design and manufacture heat exchangers and steam generators within the wide range of operating conditions without additional expenses on the research and development work

  12. Empirical component model to predict the overall performance of heating coils: Calibrations and tests based on manufacturer catalogue data

    International Nuclear Information System (INIS)

    Ruivo, Celestino R.; Angrisani, Giovanni

    2015-01-01

    Highlights: • An empirical model for predicting the performance of heating coils is presented. • Low and high heating capacity cases are used for calibration. • Versions based on several effectiveness correlations are tested. • Catalogue data are considered in approach testing. • The approach is a suitable component model to be used in dynamic simulation tools. - Abstract: A simplified methodology for predicting the overall behaviour of heating coils is presented in this paper. The coil performance is predicted by the ε-NTU method. Usually manufacturers do not provide information about the overall thermal resistance or the geometric details that are required either for the device selection or to apply known empirical correlations for the estimation of the involved thermal resistances. In the present work, heating capacity tables from the manufacturer catalogue are used to calibrate simplified approaches based on the classical theory of heat exchangers, namely the effectiveness method. Only two reference operating cases are required to calibrate each approach. The validity of the simplified approaches is investigated for a relatively high number of operating cases, listed in the technical catalogue of a manufacturer. Four types of coils of three sizes of air handling units are considered. A comparison is conducted between the heating coil capacities provided by the methodology and the values given by the manufacturer catalogue. The results show that several of the proposed approaches are suitable component models to be integrated in dynamic simulation tools of air conditioning systems such as TRNSYS or EnergyPlus

  13. Evaluation of inductive heating energy of a PF insert coil conductor by the calorimetric method (Contract research)

    International Nuclear Information System (INIS)

    Matsui, Kunihiro; Nabara, Yoshihiro; Nunoya, Yoshihiko; Koizumi, Norikiyo; Okuno, Kiyoshi

    2009-02-01

    The PF Insert Coil is a single layer solenoid coil using a superconducting conductor designed for ITER, housed in a Poloidal field coil and installed in the bore of the CS Model Coil. A stability test of the conductor will be performed in a magnetic field generated by the CS Model Coil. In this test, the inductive heat of an inductive heater attached to the conductor will be applied to initiate a normal zone in the conductor. Since the conductor for the PF Insert Coil is a cable-in-conduit conductor, it is quite difficult to estimate inductive heating energy theoretically. Thus, the inductive heating energy is measured experimentally by the calorimetric method. The heating energy is in proportion to a constant multiplied by the integrated square of an applied sinusoidal current wave over the heating period. Experimental results show that the proportional constants of the conductor, cable, conduit and dummy conductor are 0.138 [J/A 2 s], 0.028 [J/A 2 s], 0.118 [J/A 2 s] and 0.009 [J/A 2 s], respectively. The first three denote not only the inductive heating but also the joule heating of the inductive heater. The final value denotes joule heating only. Therefore, subtracting the first three constants by the last one, the proportional constants of inductive heating generated in the conductor, cable and conduit are estimated to be 0.129 [J/A 2 s], 0.019 [J/A 2 s] and 0.109 [J/A 2 s], respectively. (author)

  14. A novel design method for ground source heat pump

    Directory of Open Access Journals (Sweden)

    Dong Xing-Jie

    2014-01-01

    Full Text Available This paper proposes a novel design method for ground source heat pump. The ground source heat pump operation is controllable by using several parameters, such as the total meters of buried pipe, the space between wells, the thermal properties of soil, thermal resistance of the well, the initial temperature of soil, and annual dynamic load. By studying the effect of well number and well space, we conclude that with the increase of the well number, the inlet and outlet water temperatures decrease in summer and increase in winter, which enhance the efficiency of ground source heat pump. The well space slightly affects the water temperatures, but it affects the soil temperature to some extent. Also the ground source heat pump operations matching with cooling tower are investigated to achieve the thermal balance. This method greatly facilitates ground source heat pump design.

  15. Heat transfer enhancement of Al_2O_3-EG nanofluid in a car radiator with wire coil inserts

    International Nuclear Information System (INIS)

    Goudarzi, K.; Jamali, H.

    2017-01-01

    Highlights: • The purpose of this paper is heat transfer enhancement in a car radiator. • The simultaneous impacts of nanofluid EG/Al_2O_3 with wire coil inserts are studied. • Results show that the thermal performance enhancement up to 14%. • With increasing speed of cooling fan, Nusselt number at Reynolds numbers increased. - Abstract: In this experimental study, Aluminums Oxide (Al_2O_3) in Ethylene Glycol (EG) as nanofluid was used for heat transfer enhancement in car radiator together with wire coil inserts. Two wire coils inserts with different geometry and nanofluids with volume concentrations of 0.08%, 0.5% and 1% were investigated. The results indicated that the use of coils inserts enhanced heat transfer rates up to 9%. In addition, the simultaneous use of the coils inserts with the nanofluid with concentration of 0.08%, 0.5% and 1% resulted the thermal performance enhancement up to 5% as compared to the use of coils inserts alone.

  16. Ohmic heating coil power supply using thyristor circuit breaker in a thermonuclear fusion device

    International Nuclear Information System (INIS)

    Tani, Keiji; Shimada, Ryuichi; Tamura, Sanae; Yabuno, Kohei; Koseki, Shoichiro.

    1982-01-01

    In a large scale Tokamak thermonuclear fusion device such as the critical plasma testing facility (JT60) presently under construction, mechanical breakers such as vacuum and air breakers are mostly used for interrupting DC heavy current which is supplied to the ohmic heating coils of inductive energy accumulation method. The practical use of the DC breakers employing thyristors has just been started because the history of thyristor development is short and thristors are still expensive, in spite of the advantages. In this paper, the circuit is investigated in which the excellent high speed controllability of thyristors is fully utilized, while the economy is taken into accout, and the experiment carried out with a unit model is described. It was found that a thyristor switch, which was constructed by connecting the high speed thyristors of peak off-state voltage rating 2,000 V and mean current rating 500 A in direct parallel, was able to interrupt 12.7 kA current in the power supply circuit of ohmic heating coils developed this time. In addition, the switch configuration was able to be greatly simplified. When the multistage raising of plasma current is required, the raise can be performed with a single thyristor breaker because it can make high speed control. Therefore, the capacity of the breaker can be doubly and drastically reduced. Also, if current unbalance might occur between thyristor switch units, it gives no problem since the time of reverse voltage after current interruption dispersed smaller as current increased. (Wakatsuki, Y.)

  17. An assessment of heat transfer models of water flow in helically coiled tubes based on selected experimental datasets

    International Nuclear Information System (INIS)

    Gou, Junli; Ma, Haifu; Yang, Zijiang; Shan, Jianqiang

    2017-01-01

    Highlights: •A review of heat transfer characteristics for water flow in helically coiled tubes are conducted. •An assessment of heat transfer models under different heat transfer modes in helically coiled tubes are performed. •This work could provide references for the use of the correlations and for further studies. -- Abstract: This paper presents an assessment of the heat transfer models under different heat transfer modes for water flow in helically coiled tubes based on the compiled datasets from the reviewed literatures. For single phase flow, most of the correlations of the heat transfer coefficient can fit well to the experiments. The correlations of Xin-Ebadian, Dravid and Kalb-Seader for laminar flow and those of Seban-McLaughlim, Mori-Nakayama, Xin-Ebadian, Hardik, Rogers-Mayhew, Mikaila-Poskas and El-Genk-Schriener for turbulent flow are recommended. For flow boiling heat transfer, Steiner-Taborek correlation could be utilized to predict the boiling heat transfer coefficients in helically coiled tubes for a relatively wide range of parameters. For dryout quality, the correlations of Hwang et al. and Santini et al. give relatively better predictions than others. However, more accurate correlations for flow boiling heat transfer coefficient and dryout quality need to be developed based on further investigations with wider parameter ranges in the future. The present work could provide references for the investigators for future uses of those correlations and for performing further investigations on the heat transfer characteristics of water flow in helically coiled tubes.

  18. Mass and heat transfer at the outer surface of helical coils under single and two phase flow

    International Nuclear Information System (INIS)

    Abdel-Aziz, M.H.; Nirdosh, I.; Sedahmed, G.H.

    2016-01-01

    Highlights: • The work aims to develop reactors which need rapid temperature control. • Mass and heat transfer at the outer surface of helical coils was studied experimentally. • The experiments were conducted under gas sparing, single and two phase flow. • Variables were helical tube diameter, physical properties, and gas and liquid velocity. • Results verification in terms of natural convection and surface renewal mechanism was explained. - Abstract: The mass transfer behavior of the outer surface of vertical helical coil was studied by the electrochemical technique under single phase flow, gas sparging and two phase flow. Variables studied were helical tube diameter, physical properties of the solution, solution velocity and superficial gas velocity. The mass transfer data were correlated by dimensionless equations. Mass transfer enhancement ratio in case of two phase flow ranged from 1.1 to 4.9 compared to single phase flow. Implication of the results for the design and operation of helical coil reactors used to conduct L–S exothermic diffusion controlled reactions which need rapid temperature control were outlined. In this case the inner coil surface will act as a cooler while the outer surface will act a reaction surface. Immobilized enzyme catalyzed biochemical reactions where heat sensitive materials may be involved represent an example for the reactions which can employ the helical coil reactor. Also the importance of the results in the design of and operation of diffusion controlled membrane processes which employ helical coil membrane was noted. In view of the analogy between heat and mass transfer the possibility of using the results in the design and operation of helical coil heat exchangers was highlighted.

  19. Guide for the calculation of heating capacity and heating coils for deep tanks / Handleiding bij de berekening van verwarmingskapasiteit en spiraallengte voor dieptanks

    NARCIS (Netherlands)

    Heeden, D.J. van der; Koppenol, A.D.

    1972-01-01

    This report deals with a method for calculating the heating capacity and the length of heating coils, required for deep tanks in dry cargo ships. It is based on the theory of natural convection and on experiments, carried out on tanks loaded with mineral oils. The calculating method is set up for

  20. Evaluation of the thermal efficiency and a cost analysis of different types of ground heat exchangers in energy piles

    International Nuclear Information System (INIS)

    Yoon, Seok; Lee, Seung-Rae; Xue, Jianfeng; Zosseder, Kai; Go, Gyu-Hyun; Park, Hyunku

    2015-01-01

    Highlights: • We performed field TPT with W and coil-type GHEs in energy piles. • We evaluated heat exchange rates from TPT results. • Field TPT results were compared with numerical analysis. • Cost analysis with GSHP design method was conducted for each type of GHEs in energy piles. - Abstract: This paper presents an experimental and numerical study of the results of a thermal performance test using precast high-strength concrete (PHC) energy piles with W and coil-type ground heat exchangers (GHEs). In-situ thermal performance tests (TPTs) were conducted for four days under an intermittent operation condition (8 h on; 16 h off) on W and coil-type PHC energy piles installed in a partially saturated weathered granite soil deposit. In addition, three-dimensional finite element analyses were conducted and the results were compared with the four-day experimental results. The heat exchange rates were also predicted for three months using the numerical analysis. The heat exchange rate of the coil-type GHE showed 10–15% higher efficiency compared to the W-type GHE in the energy pile. However, in considering the cost for the installation of the heat exchanger and cement grouting the additional cost of W-type GHE in energy pile was 200–250% cheaper than coil-type GHE under the condition providing equivalent thermal performance. Furthermore, the required lengths of the W, 3U and coil-type GHEs in the energy piles were calculated based on the design process of Kavanaugh and Rafferty. The additional cost for the W and 3U types of GHEs were also 200–250% lower than that of the coil-type GHE. However, the required number of piles was much less with the coil-type GHE as compared to the W and 3U types of GHEs. They are advantageous in terms of the construction period, and further, selecting the coil-type GHE could be a viable option when there is a limitation in the number of piles in consideration of the scale of the building.

  1. Heat transfer analysis of underground U-type heat exchanger of ground source heat pump system.

    Science.gov (United States)

    Pei, Guihong; Zhang, Liyin

    2016-01-01

    Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions of a continuous and intermittent operation over 7 days on a GSHP with a single-well, single-U and double-U heat exchanger and the impact of single-U and double-U buried heat pipes on the surrounding rock-soil temperature field and the impact of intermittent operation and continuous operation on the outlet water temperature. The influence on the rock-soil temperature is approximately 13 % higher for the double-U heat exchanger than that of the single-U heat exchanger. The extracted energy of the intermittent operation is 36.44 kw·h higher than that of the continuous mode, although the running time is lower than that of continuous mode, over the course of 7 days. The thermal interference loss and quantity of heat exchanged for unit well depths at steady-state condition of 2.5 De, 3 De, 4 De, 4.5 De, 5 De, 5.5 De and 6 De of sidetube spacing are detailed in this work. The simulation results of seven working conditions are compared. It is recommended that the side-tube spacing of double-U underground pipes shall be greater than or equal to five times of outer diameter (borehole diameter: 180 mm).

  2. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mittereder, Nick [IBACOS, Inc., Pittsburgh, PA (United States); Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season.

  3. Ground collectors for heat pumps; Grondcollectoren voor warmtepompen

    Energy Technology Data Exchange (ETDEWEB)

    Van Krevel, A. [Techneco, Leidschendam (Netherlands)

    1999-10-01

    The dimensioning and cost optimisation of a closed vertical ground collector system has been studied. The so-called Earth Energy Designer (EED) computer software, specially developed for the calculations involved in such systems, proved to be a particularly useful tool. The most significant findings from the first part of the study, 'Heat extraction from the ground', are presented and some common misconceptions about ground collector systems are clarified. 2 refs.

  4. Geothermal heat pumps - gaining ground in the UK and worldwide

    International Nuclear Information System (INIS)

    Curtis, Robin

    2001-01-01

    This 2001 edition of the guide to UK renewable energy companies examines the geothermal heat pump sector, and discusses the technology involved, installations of geothermal heat pumps, the activity in the UK market with increased interest in UK geothermal heat pump products from abroad, and developments in the building sector. The UK government's increased support for the industry including its sponsorship of the Affordable Warmth programme, and the future potential of ground source systems are discussed

  5. Study on finned pipe performance as a ground heat exchanger

    Science.gov (United States)

    Lin, Qinglong; Ma, Jinghui; Shi, Lei

    2017-08-01

    The GHEs (ground heat exchangers) is an important element that determines the thermal efficiency of the entire ground-source heat-pump system. The aim of the present study is to clarify thermal performance of a new type GHE pipe, which consists straight fins of uniform cross sectional area. In this paper, GHE model is introduced and an analytical model of new type GHE pipe is developed. The heat exchange rate of BHEs utilizing finned pips is 40.42 W/m, which is 16.3% higher than normal BHEs, based on simulation analyses.

  6. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    Energy Technology Data Exchange (ETDEWEB)

    Mittereder, N.; Poerschke, A.

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.

  7. Performance of cable-in-conduit conductors in ITER [International Thermonuclear Experimental Reactor] toroidal field coils with varying heat loads

    International Nuclear Information System (INIS)

    Kerns, J.A.; Wong, R.L.

    1989-01-01

    The toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) will operate with varying heat loads generated by ac losses and nuclear heating. The total heat load is estimated to be 2 kW per TF coil under normal operation and can be higher for different operating scenarios. Ac losses are caused by ramping the poloidal field (PF) for plasma initiation, burn, and shutdown; nuclear heating results from neutrons that penetrate into the coil past the shield. Present methods to reduce or eliminate these losses lead to larger and more expensive machines, which are unacceptable with today's budget constraints. A suitable solution is to design superconductors that operate with high heat loads. The cable-in-conduit conductor (CICC) can operate with high heat loads. One CICC design is analyzed for its thermal performance using two computer codes developed at LLNL. One code calculates the steady state flow conditions along the flow path, while the other calculates the transient conditions in the flow. We have used these codes to analyze the superconductor performance during the burn phase of the ITER plasma. The results of these analyses give insight to the choice of flow rate on superconductor performance. 4 refs., 5 figs

  8. Annual simulations of heat pump systems with vertical ground heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, M.A.; Randriamiarinjatovo, D. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Mecanique

    2001-06-01

    The recent increased popularity in ground-coupled heat pump (GCHP) systems is due to their energy saving potential. However, in order for a GCHP to operate efficiently, they must be sized correctly. This paper presents a method to perform annual simulations of GCHP systems to optimize the length of the ground heat exchanger and provide annual energy consumption data. A computer program has been developed to simulate the building load, heat pump and the ground heat exchanger, the three most distinct parts of the system. The coupled governing equations of these three models are solved simultaneously until a converged solution is obtained at each time step. The simulations are performed using the Engineering Equation Solver (EES). This program has proven to be useful in balancing ground heat exchanger length against heat pump energy consumption.15 refs., 9 figs.

  9. A study on nuclear heat load tolerable for NET/TF coils cooled by internal flow of helium II

    International Nuclear Information System (INIS)

    Hofmann, A.

    1988-02-01

    NbTi cables cooled by internal flow of superfluid helium are considered an option for the design of NET/TF coils with about 11 T peak fields. Starting from an available winding cross section of 0.61x0.61 m 2 for a 8 MA turns coil made of a 16 kA conductor it is shown that sufficient hydraulic cross section can be provided within such cables to remove the expected thermal load resulting from nuclear heating with exponential decay from inboard to outboard side of the winding. The concept is a pancake type coil with 1.8 K helium fed-in the high field region of each pancake. The temperature distribution within such coils is calculated, and the local safety margin is determined from temperature and field. The calculation takes account of nuclear and a.c. heating, and of thermal conductance between the individual layers and the coil casing. It is shown that operation with 1.8 K inlet and about 3 K outlet temperature is possible. The electrical insulation with about 0.5 mm thickness proves to provide sufficient thermal insulation. No additional thermal shield is required between the coil casing and the winding package. Two different types of conductors are being considered: a) POLO type cable with quadratic cross section and a central circular coolant duct, and b) an LCT type cable with two conductors wound in hand. Both concepts with about 500 m length of the cooland channels are shown to meet the requirements resulting from a peak nuclear heat load of 0.3 mW/cm 3 in the inboard turns. The hydraulic diameters are sufficient to operate each coils with self-sustained fountain effect pumps. Even appreciably higher heat loads with up to 3 mW/cm 3 of nuclear heating can be tolerated for the POLO type cable when the hydraulic diameter is enlarged to its maximum of 17 mm. (orig.) [de

  10. Method to reduce non-specific tissue heating of small animals in solenoid coils.

    Science.gov (United States)

    Kumar, Ananda; Attaluri, Anilchandra; Mallipudi, Rajiv; Cornejo, Christine; Bordelon, David; Armour, Michael; Morua, Katherine; Deweese, Theodore L; Ivkov, Robert

    2013-01-01

    Solenoid coils that generate time-varying or alternating magnetic fields (AMFs) are used in biomedical devices for research, imaging and therapy. Interactions of AMF and tissue produce eddy currents that deposit power within tissue, thus limiting effectiveness and safety. We aim to develop methods that minimise excess heating of mice exposed to AMFs for cancer therapy experiments. Numerical and experimental data were obtained to characterise thermal management properties of water using a continuous, custom water jacket in a four-turn simple solenoid. Theoretical data were obtained with method-of-moments (MoM) numerical field calculations and finite element method (FEM) thermal simulations. Experimental data were obtained from gel phantoms and mice exposed to AMFs having amplitude >50 kA/m and frequency of 160 kHz. Water has a high specific heat and thermal conductivity, is diamagnetic, polar, and nearly transparent to magnetic fields. We report at least a two-fold reduction of temperature increase from gel phantom and animal models when a continuous layer of circulating water was placed between the sample and solenoid, compared with no water. Thermal simulations indicate the superior efficiency in thermal management by the developed continuous single chamber cooling system over a double chamber non-continuous system. Further reductions of heating were obtained by regulating water temperature and flow for active cooling. These results demonstrate the potential value of a contiguous layer of circulating water to permit sustained exposure to high intensity alternating magnetic fields at this frequency for research using small animal models exposed to AMFs.

  11. Ground Source Geothermal District Heating and Cooling System

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, James William [Ball State Univ., Muncie, IN (United States)

    2016-10-21

    Ball State University converted its campus from a coal-fired steam boiler district heating system to a ground source heat pump geothermal district system that produces simultaneously hot water for heating and chilled water for cooling. This system will include the installation of 3,600 four hundred feet deep vertical closed loop boreholes making it the largest ground source geothermal district system in the country. The boreholes will act as heat exchangers and transfer heat by virtue of the earth’s ability to maintain an average temperature of 55 degree Fahrenheit. With growing international concern for global warming and the need to reduce worldwide carbon dioxide loading of the atmosphere geothermal is poised to provide the means to help reduce carbon dioxide emissions. The shift from burning coal to utilizing ground source geothermal will increase electrical consumption but an overall decrease in energy use and reduction in carbon dioxide output will be achieved. This achievement is a result of coupling the ground source geothermal boreholes with large heat pump chiller technology. The system provides the thermodynamic means to move large amounts of energy with limited energy input. Ball State University: http://cms.bsu.edu/About/Geothermal.aspx

  12. Conception of Brownian coil

    OpenAIRE

    Zhang, Jiayuan

    2018-01-01

    This article proposes a conception of Brownian coil. Brownian coil is a tiny coil with the same size of pollen. Once immersed into designed magnetic field and liquid, the coil will be moved and deformed macroscopically, due to the microscopic thermodynamic molecular collisions. Such deformation and movement will change the magnetic flux through the coil, by which an ElectroMotive Force (EMF) is produced. In this work, Brownian heat exchanger and Brownian generator are further designed to tran...

  13. Thermal Performance Analyses of Multiborehole Ground Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Wanjing Luo

    2017-01-01

    Full Text Available Geothermal energy known as a clean, renewable energy resource is widely available and reliable. Ground heat exchangers (GHEs can assist the development of geothermal energy by reducing the capital cost and greenhouse gas emission. In this paper, a novel semianalytical method was developed to study the thermal performance of multiborehole ground heat exchangers (GHEs with arbitrary configurations. By assuming a uniform inlet fluid temperature (UIFT, instead of uniform heat flux (UHF, the effects of thermal interference and the thermal performance difference between different boreholes can be examined. Simulation results indicate that the monthly average outlet fluid temperatures of GHEs will increase gradually while the annual cooling load of the GHEs is greater than the annual heating load. Besides, two mechanisms, the thermal dissipation and the heat storage effect, will determine the heat transfer underground, which can be further divided into four stages. Moreover, some boreholes will be malfunctioned; that is, boreholes can absorb heat from ground when the GHEs are under the cooling mode. However, as indicated by further investigations, this malfunction can be avoided by increasing borehole spacing.

  14. Factors Influencing the Thermal Efficiency of Horizontal Ground Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Eloisa Di Sipio

    2017-11-01

    Full Text Available The performance of very shallow geothermal systems (VSGs, interesting the first 2 m of depth from ground level, is strongly correlated to the kind of sediment locally available. These systems are attractive due to their low installation costs, less legal constraints, easy maintenance and possibility for technical improvements. The Improving Thermal Efficiency of horizontal ground heat exchangers Project (ITER aims to understand how to enhance the heat transfer of the sediments surrounding the pipes and to depict the VSGs behavior in extreme thermal situations. In this regard, five helices were installed horizontally surrounded by five different backfilling materials under the same climatic conditions and tested under different operation modes. The field test monitoring concerned: (a monthly measurement of thermal conductivity and moisture content on surface; (b continuous recording of air and ground temperature (inside and outside each helix; (c continuous climatological and ground volumetric water content (VWC data acquisition. The interactions between soils, VSGs, environment and climate are presented here, focusing on the differences and similarities between the behavior of the helix and surrounding material, especially when the heat pump is running in heating mode for a very long time, forcing the ground temperature to drop below 0 °C.

  15. Evaluation of the transfer of heat from the coil of the LHC dipole magnet to Helium II

    International Nuclear Information System (INIS)

    Richter, D.; Sevred, A.; Fleiter, J.; Baudouy, B.; Devred, A.

    2007-01-01

    During operation of the Large Hadron Collider at CERN, heat will be generated inside the coils of its superconducting magnets as a consequence of ramping of magnetic field, and of the interaction of lost beam particles with the magnet mass. Heat has to be transferred from the conductor into the He II coolant and removed from the magnet environment. During the LHC R and D stage, this transfer has been extensively studied on simulated coil segments at CEA/Saclay, and by analyzing dynamic behavior of short model magnets at CERN. Owing to the importance of efficient cooling for the design of future superconducting accelerator magnets, study of heat transfer has been restored at CERN and in frame of the Next European Dipole Collaboration. The article features two recently performed works: 1) Attempt to analyse archived high ramp rate quench data of 1-m-long LHC model dipole magnets of the 2. generation. 2) Development of a method for direct measurement of heat transfer on segments of production LHC dipole magnet coils. (authors)

  16. Ground-source heat pump systems in Norway

    International Nuclear Information System (INIS)

    Stene, Joern

    2007-01-01

    The Norwegian ground source heat pump (GSHP) market is reviewed. Boreholes in bedrock are of growing interest for residential systems and of growing interest for larger systems with thermal recharging or thermal energy storage. Ground water is limited to areas where the water has acceptable purity. Challenges and important boundary conditions include 1) high quality GSHP system requires engineering expertise, 2) new building codes and EU directive 'energy performance of buildings.'(2006), and 3) hydronic floor heating systems in 50 percent of new residences (author) (ml)

  17. Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

    Science.gov (United States)

    Nada, S. A.; Elattar, H. F.; Fouda, A.; Refaey, H. A.

    2018-03-01

    In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

  18. Experimental studies on a ground coupled heat pump with solar thermal collectors for space heating

    International Nuclear Information System (INIS)

    Xi, Chen; Hongxing, Yang; Lin, Lu; Jinggang, Wang; Wei, Liu

    2011-01-01

    This paper presents experimental studies on a solar-assisted ground coupled heat pump (SAGCHP) system for space heating. The system was installed at the Hebei Academy of Sciences in Shijiazhuang (lat. N38 o 03', long. E114 o 26'), China. Solar collectors are in series connection with the borehole array through plate heat exchangers. Four operation modes of the system were investigated throughout the coldest period in winter (Dec 5th to Dec 27th). The heat pump performance, borehole temperature distributions and solar colleting characteristics of the SAGCHP system are analyzed and compared when the system worked in continuous or intermittent modes with or without solar-assisted heating. The SAGCHP system is proved to perform space heating with high energy efficiency and satisfactory solar fraction, which is a promising substitute for the conventional heating systems. It is also recommended to use the collected solar thermal energy as an alternative source for the heat pump instead of recharging boreholes for heat storage because of the enormous heat capacity of the earth. -- Highlights: → We study four working modes of a solar-assisted ground coupled heat pump. → The heating performance is in direct relation with the borehole temperature. → Solar-assisted heating elevates borehole temperature and system performance. → The system shows higher efficiency over traditional heating systems in cold areas. → Solar heat is not suggested for high temperature seasonal storage.

  19. Estimating the CO2 mitigation potential of horizontal Ground Source Heat Pumps in the UK

    Science.gov (United States)

    Garcia-Gonzalez, R.; Verhoef, A.; Vidale, P. L.; Gan, G.; Chong, A.; Clark, D.

    2012-04-01

    By 2020, the UK will need to generate 15% of its energy from renewables to meet our contribution to the EU renewable energy target. Heating and cooling systems of buildings account for 30%-50% of the global energy consumption; thus, alternative low-carbon technologies such as horizontal Ground Couple Heat Pumps (GCHPs) can contribute to the reduction of anthropogenic CO2 emissions. Horizontal GCHPs currently represent a small fraction of the total energy generation in the UK. However, the fact that semi-detached and detached dwellings represent approximately 40% of the total housing stocks in the UK could make the widespread implementation of this technology particularly attractive in the UK and so could significantly increase its renewable energy generation potential. Using a simulation model, we analysed the dynamic interactions between the environment, the horizontal GCHP heat exchanger and typical UK dwellings, as well as their combined effect on heat pump performance and CO2 mitigation potential. For this purpose, a land surface model (JULES, Joint UK Land Environment Simulator), which calculates coupled soil heat and water fluxes, was combined with a heat extraction model. The analyses took into account the spatio-temporal variability of soil properties (thermal and hydraulic) and meteorological variables, as well as different horizontal GCHP configurations and a variety of building loads and heat demands. Sensitivity tests were performed for four sites in the UK with different climate and soil properties. Our results show that an installation depth of 1.0m would give us higher heat extractions rates, however it would be preferable to install the pipes slightly deeper to avoid the seasonal influence of variable meteorological conditions. A value of 1.5m for the spacing between coils (S) for a slinky configuration type is recommended to avoid thermal disturbances between neighbouring coils. We also found that for larger values of the spacing between the coils

  20. ITER central solenoid model coil heat treatment complete and assembly started

    International Nuclear Information System (INIS)

    Thome, R.J.; Okuno, K.

    1998-01-01

    A major R and D task in the ITER program is to fabricate a Superconducting Model Coil for the Central Solenoid to establish the design and fabrication methods for ITER size coils and to demonstrate conductor performance. Completion of its components is expected in 1998, to be followed by assembly with structural components and testing in a facility at JAERI

  1. Heating and cooling with ground-loop heat pumps; Heizen und Kuehlen mit erdgekoppelten Waermepumpen

    Energy Technology Data Exchange (ETDEWEB)

    Afjei, Th.; Dott, R. [Institut Energie am Bau, Fachhochschule Nordwestschweiz (FHNW), Muttenz (Switzerland); Huber, A. [Huber Energietechnik AG, Zuerich (Switzerland)

    2007-08-15

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of the SFOE-project 'Heating and cooling with ground coupled heat pumps' in which the benefits and costs of a heat pump heating and cooling system with a borehole heat exchanger were examined. In particular the dimensioning of the hydraulic system, control concept and user behaviour are dealt with. The results of the simulations of thermal building behaviour with MATLAB/SIMULINK, CARNOT, and EWS are discussed. The results of parameter studies carried out, including varying shading, cooling characteristic curves, temperature differences in the heat exchanger and the dead time between heating and cooling mode are discussed. These showed that a simple system with heat pump and borehole heat exchanger for heating or preparation of domestic hot water as well as for passive cooling proved to be the best choice.

  2. Study on hybrid ground-coupled heat pump systems

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Man; Hongxing, Yang [Renewable Energy Research Group, The Hong Kong Polytechnic University, Hong Kong (China); Zhaohong, Fang [School of Thermal Energy Engineering, Shandong Architecture University, Jinan (China)

    2008-07-01

    Although ground-coupled heat pump (GCHP) systems are becoming attractive air-conditioning systems in some regions, the significant drawback for their wider application is the high initial cost. Besides, more energy is rejected into ground by the GCHP system installed in cooling-dominated buildings than the energy extracted from ground on an annual basis and this imbalance can result in the degradation of system performance. One of the available options that can resolve these problems is to apply the hybrid ground-coupled heat pump (HGCHP) systems, with supplemental heat rejecters for rejecting extra thermal energy when they are installed in cooling-dominated buildings. This paper presents a practical hourly simulation model of the HGCHP system by modeling the heat transfer of its main components. The computer program developed on this hourly simulation model can be used to calculate the operating data of the HGCHP system according to the building load. The design methods and running control strategies of the HGCHP system for a sample building are investigated. The simulation results show that proper HGCHP system can effectively reduce both the initial cost and the operating cost of an air-conditioning system compared with the traditional GCHP system used in cooling-dominated buildings. (author)

  3. Comparative study of heat transfer from Nb-Ti and Nb_{3}Sn coils to He II

    Directory of Open Access Journals (Sweden)

    Marco La China

    2008-08-01

    Full Text Available In superconducting magnets, the energy deposited or generated in the coil must be evacuated to prevent temperature rise and consequent transition of the superconductor to the resistive state. The main barrier to heat extraction is represented by the electric insulation wrapped around superconducting cables. In the LHC, insulation improvement is a key point in the development of interaction region magnets and injector chain fast-pulsed magnets for luminosity upgrade; the high heat load of these magnets, in fact, is not compatible with the use of current insulation schemes. We review the standard insulation schemes for Nb-Ti and Nb_{3}Sn technology from the thermal point of view. We implement, in an analytical model, the strongly nonlinear thermal resistances of the different coil components including the permeability to superfluid helium of Nb-Ti insulations, measured during the LHC main dipole development. We use such a model to compare Nb-Ti and Nb_{3}Sn technologies by taking into account their specific operating margin in different working conditions. Finally, we propose an insulation scheme to enhance the heat transfer capability of Nb-Ti coils.

  4. Experimental investigation of the reverse heat transfer of R134a flow through non-adiabatic coiled capillary tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zareh, Masoud; Heidari, Mohammad Ghorbani [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-07-15

    This research represents an experimental investigation of the metastable flow and re-condensation phenomenon through non-adiabatic lateral helical capillary tubes and suction tube heat exchanger. The results show that mass flux ratio has a vital role: It affects metastable flow and also reverse heat transfer phenomenon through non-adiabatic helical capillary tube. Therefore, by increasing of the mass flux ratio, the rate of heat transfer between them decreases. In contrast to the strong rate condition of heat transfer between them, reverse heat transfer or re-condensation maybe happen. Moreover, experimental results show that for R134 flow with mass flux ratio more than 57.84, metastable flow exists in non-adiabatic capillary tube with 0.9144 mm inner diameter, 30 mm coil diameter, 6.18 m length, 4 mm inner diameter of compressor suction tube.

  5. Current status of ground-source heat pumps in China

    International Nuclear Information System (INIS)

    Yang Wei; Zhou Jin; Xu Wei; Zhang Guoqiang

    2010-01-01

    As a renewable energy technology, the ground-source heat pump (GSHP) technologies have increasingly attracted world-wide attention due to their advantages of energy efficiency and environmental friendliness. This paper presents Chinese research and application on GSHP followed by descriptions of patents. The policies related to GSHP are also introduced and analyzed. With the support of Chinese government, several new heat transfer models and two new GSHP systems (named pumping and recharging well (PRW) and integrated soil cold storage and ground-source heat pump (ISCS and GSHP) system) have been developed by Chinese researchers. The applications of GSHP systems have been growing rapidly since the beginning of the 21st century with financial incentives and supportive government policies. However, there are still several challenges for the application of GSHP systems in large scale. This paper raises relevant suggestions for overcoming the existing and potential obstacles. In addition, the developing and applying prospects of GSHP systems in China are also discussed.

  6. Advanced control for ground source heat pump systems

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Patrick [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gehl, Anthony C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Xiaobing [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    Ground source heat pumps (GSHP), also known as geothermal heat pumps (GHP), are proven advanced HVAC systems that utilize clean and renewable geothermal energy, as well as the massive thermal storage capacity of the ground, to provide space conditioning and water heating for both residential and commercial buildings. GSHPs have higher energy efficiencies than conventional HVAC systems. It is estimated, if GSHPs achieve a 10% market share in the US, in each year, 0.6 Quad Btu primary energy consumption can be saved and 36 million tons carbon emissions can be avoided (Liu et al. 2017). However, the current market share of GSHPs is less than 1%. The foremost barrier preventing wider adoption of GSHPs is their high installation costs. To enable wider adoption of GSHPs, the costeffectiveness of GSHP applications must be improved.

  7. Performance Evaluation of a Helical Coil Heat Exchanger Working under Supercritical Conditions in a Solar Organic Rankine Cycle Installation

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2016-06-01

    Full Text Available Worldwide interest in low grade heat valorization using organic Rankine cycle (ORC technologies has increased significantly. A new small-scale ORC with a net capacity of 3 kW was efficiently integrated with a concentrated solar power technology for electricity generation. The excess heat source from Photovoltaic (PV collectors with a maximum temperature of 100 °C was utilized through a supercritical heat exchanger that uses R-404A as working medium. By ensuring supercritical heat transfer leads to a better thermal match in the heat exchanger and improved overall cycle efficiency. A helical coil heat exchanger was designed by using heat transfer correlations from the literature. These heat transfer correlations were derived for different conditions than ORCs and their estimated uncertainty is ~20%. In order to account for the heat transfer correlation uncertainties this component was oversized by 20%. Next, a prototype was built and installed in an integrated concentrated photovoltaic/thermal (CPV/T/Rankine system. The results from the measurements show that for better estimation of the sizing of the heat exchanger a more accurate correlation is required in order to design an optimal configuration and thus employ cheaper components.

  8. 'Investigation on the heat dissipation characteristics of electromagnetic coil for high temperature applications

    International Nuclear Information System (INIS)

    Saran, Shiv Raj; Taly, Y. K.; Mahapatra, U.; Chandraker, D.K.

    2011-01-01

    Full text: Function of electromagnetic coil is to generate magnetic flux for electromechanical devices like linear actuator, motor etc. Electromagnetic coils are used in the Advanced Magnetic Jack Mechanism (AMJM) and In-Vessel Control Rod Drive Mechanism (IV CRDM) to control the motion of the rod in the reactor. This paper describes results of the thermal analysis with several candidate materials to design the electromagnetic coil for desired high temperature (∼ 350 deg C) service life by using well established software to study the thermal design for in-vessel control rod drive mechanism. A test model of electromagnetic coil is fabricated and tested at room temperature (30 deg C). The measured temperatures from the test model at selected locations (along radial and axial direction) have been used to validate the design methodology by finite element analysis. Various candidate materials (Ceramic fiber, glass fiber, mineral insulated conductors) for electromagnetic coil have been analyzed to investigate the suitability for high temperature (∼ 350 deg C) applications. This study will be useful for designing electromagnetic coils for in-vessel control rod drive mechanism

  9. Energy and exergy analysis of a ground-coupled heat pump system with two horizontal ground heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa; Pihtili, Kazim [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23119 Elazig (Turkey)

    2007-10-15

    In this paper we investigate of energetic and exergetic efficiencies of ground-coupled heat pump (GCHP) system as a function of depth trenches for heating season. The horizontal ground heat exchangers (HGHEs) were used and it were buried with in 1 m (HGHE1) and 2 m (HGHE2) depth trenches. The energy efficiency of GCHP systems are obtained to 2.5 and 2.8, respectively, while the exergetic efficiencies of the overall system are found to be 53.1% and 56.3%, respectively, for HGHE1 and HGHE2. The irreversibility of HGHE2 is less than of the HGHE1 as about 2.0%. The results show that the energetic and exergetic efficiencies of the system increase when increasing the heat source (ground) temperature for heating season. And the end of this study, we deal with the effects of varying reference environment temperature on the exergy efficiencies of HGHE1 and HGHE2. The results show that increasing reference environment temperature decreases the exergy efficiency in both HGHE1 and HGHE2. (author)

  10. Thermal performance and pressure drop of spiral-tube ground heat exchangers for ground-source heat pump

    International Nuclear Information System (INIS)

    Jalaluddin; Miyara, Akio

    2015-01-01

    Thermal performance and pressure drop of the spiral-tube GHE were evaluated in this present work. A numerical simulation tool was used to carry out this research. The heat exchange rates per meter borehole depth of the spiral-tube GHE with various pitches and their pressure drops were compared with that of the U-tube GHE. Furthermore, a comparative analysis between a spiral pipe and straight pipe was performed. In comparison with the straight pipe, using the spiral pipe in the borehole increased the heat exchange rate to the ground per meter borehole depth. However, the pressure drop of water flow also increased due to increasing the length of pipe per meter borehole depth and its spiral geometry. The accuracy of the numerical model was verified for its pressure drop with some pressure drop correlations. The heat exchange rate and pressure drop of the GHEs are presented. As an example, the heat exchange rate per meter borehole depth of spiral pipe with 0.05 m pitch in the turbulent flow increased of 1.5 times. Its pressure drop also increased of 6 times. However, from the view point of energy efficiency, using the spiral pipe in the ground-source heat pump system gives a better performance than using the straight pipe. The heat exchange rate and pressure drop are important parameter in design of the ground-source heat pump (GSHP) system. - Highlights: • Thermal performance and pressure drop of spiral-tube GHE are presented. • Effects of spiral pitch on thermal performance and pressure drop are analyzed. • Using a spiral pipe increases heat exchange rate per meter borehole depth of GHE. • Pressure drop per meter borehole depth also increases in the spiral pipe.

  11. Simulation of embedded heat exchangers of solar aided ground source heat pump system

    Institute of Scientific and Technical Information of China (English)

    王芳; 郑茂余; 邵俊鹏; 李忠建

    2008-01-01

    Aimed at unbalance of soil temperature field of ground source heat pump system, solar aided energy storage system was established. In solar assisted ground-source heat pump (SAGSHP) system with soil storage, solar energy collected in three seasons was stored in the soil by vertical U type soil exchangers. The heat abstracted by the ground-source heat pump and collected by the solar collector was employed to heating. Some of the soil heat exchangers were used to store solar energy in the soil so as to be used in next winter after this heating period; and the others were used to extract cooling energy directly in the soil by circulation pump for air conditioning in summer. After that solar energy began to be stored in the soil and ended before heating period. Three dimensional dynamic numerical simulations were built for soil and soil heat exchanger through finite element method. Simulation was done in different strata month by month. Variation and restoration of soil temperature were studied. Economy and reliability of long term SAGSHP system were revealed. It can be seen that soil temperature is about 3 ℃ higher than the original one after one year’s running. It is beneficial for the system to operate for long period.

  12. Radiative Heating in MSL Entry: Comparison of Flight Heating Discrepancy to Ground Test and Predictive Models

    Science.gov (United States)

    Cruden, Brett A.; Brandis, Aaron M.; White, Todd R.; Mahzari, Milad; Bose, Deepak

    2014-01-01

    During the recent entry of the Mars Science Laboratory (MSL), the heat shield was equipped with thermocouple stacks to measure in-depth heating of the thermal protection system (TPS). When only convective heating was considered, the derived heat flux from gauges in the stagnation region was found to be underpredicted by as much as 17 W/sq cm, which is significant compared to the peak heating of 32 W/sq cm. In order to quantify the contribution of radiative heating phenomena to the discrepancy, ground tests and predictive simulations that replicated the MSL entry trajectory were performed. An analysis is carried through to assess the quality of the radiation model and the impact to stagnation line heating. The impact is shown to be significant, but does not fully explain the heating discrepancy.

  13. Ground-Coupling with Water Source Heat Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Kavanaugh, S.

    0001-01-01

    Ground-coupled heat pumps (GCHPs) have been receiving increasing attention in recent years. In areas where the technology has been properly applied, they are the system of choice because of their reliability, high level of comfort, low demand, and low operating costs. Initially these systems were most popular in rural, residential applications where heating requirements were the primary consideration. However, recent improvements in heat pumps units and installation procedures have expanded the market to urban and commercial applications. This paper discusses some of the current activity in the commercial sector. The basic system and nomenclature are discussed. Several variations for commercial buildings are presented along with examples of systems in operation. Several advantages and disadvantages are listed. Operating and installation costs are briefly discussed. Finally, the GCHP is presented as an alternative that is able to counter much of the criticism leveled by the natural gas industry toward conventional heat pumps.

  14. Ground-Coupling with Water Source Heat Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Kavanaugh, S

    0000-12-30

    Ground-coupled heat pumps (GCHPs) have been receiving increasing attention in recent years. In areas where the technology has been properly applied, they are the system of choice because of their reliability, high level of comfort, low demand, and low operating costs. Initially these systems were most popular in rural, residential applications where heating requirements were the primary consideration. However, recent improvements in heat pumps units and installation procedures have expanded the market to urban and commercial applications. This paper discusses some of the current activity in the commercial sector. The basic system and nomenclature are discussed. Several variations for commercial buildings are presented along with examples of systems in operation. Several advantages and disadvantages are listed. Operating and installation costs are briefly discussed. Finally, the GCHP is presented as an alternative that is able to counter much of the criticism leveled by the natural gas industry toward conventional heat pumps.

  15. North Village Ground Source Heat Pump Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Redderson, Jeff

    2015-08-03

    This project demonstrated the feasibility of converting from a traditional direct exchange system to a ground source heat pump system on a large scale, multiple building apartment complex on a university campus. A total of ten apartment buildings were converted using vertical well fields and a ground source loop that connected the 24 apartments in each building into a common system. The system has yielded significant operational savings in both energy and maintenance and transformed the living environments of these residential buildings for our students.

  16. Ground Source Heat Pumps vs. Conventional HVAC: A Comparison of Economic and Environmental Costs

    Science.gov (United States)

    2009-03-26

    of systems are surface water heat pumps (SWHPs), ground water heat pumps (GWHPs), and ground coupled heat pumps ( GCHPs ) (Kavanaugh & Rafferty, 1997...Kavanaugh & Rafferty, 1997). Ground Coupled Heat Pumps (Closed-Loop Ground Source Heat Pumps) GCHPs , otherwise known as closed-loop GSHPs, are the...Significant confusion has arisen through the use of GCHP and closed-loop GSHP terminology. Closed-loop GSHP is the preferred nomenclature for this

  17. Energetic Efficiency Evaluation by Using GroundWater Heat Pumps

    Directory of Open Access Journals (Sweden)

    Tokar Adriana

    2012-09-01

    Full Text Available Romania has significant energy potential from renewable sources, but the potential used is much lower due to technical and functional disadvantages, to economic efficiency, the cost elements and environmental limitations. However, efforts are being made to integrate renewable energy in the national energy system. To promote and encourage private investments for renewable energy utilization, programs have been created in order to access funds needed to implement these technologies. Assessment of such investments was carried out from technical and economical point of view, by analyzing a heat pump using as heat source the solar energy from the ground.

  18. Development and Demonstration of a High Efficiency, Rapid Heating, Low NOx Alternative to Conventional Heating of Round Steel Shapes, Steel Substrate (Strip) and Coil Box Transfer Bars

    Energy Technology Data Exchange (ETDEWEB)

    Kurek, Harry; Wagner, John

    2010-01-25

    Direct Flame Impingement involves the use of an array of very high-velocity flame jets impinging on a work piece to rapidly heat the work piece. The predominant mode of heat transfer is convection. Because of the locally high rate of heat transfer at the surface of the work piece, the refractory walls and exhaust gases of a DFI furnace are significantly cooler than in conventional radiant heating furnaces, resulting in high thermal efficiency and low NOx emissions. A DFI furnace is composed of a successive arrangement of heating modules through or by which the work piece is conveyed, and can be configured for square, round, flat, and curved metal shapes (e.g., billets, tubes, flat bars, and coiled bars) in single- or multi-stranded applications.

  19. A Study on the Improvement Effect and Field Applicability of the Deep Soft Ground by Ground Heating Method

    Directory of Open Access Journals (Sweden)

    Mincheol Park

    2018-05-01

    Full Text Available The soft ground in coastal areas should be treated when it needs to be used for the sustainably developed of urban or industrial complex constructions. The ground heating method for soft ground improvement was applied in Eastern Europe in the 1960s, but it was not widely used due to economic and environmental problems. The author developed a device for improving soft ground using an electric heating pipe. This paper investigates the improvement effect and field application of deep soft ground by the ground heating method using the electric heating pipe. Ground heating increases the temperature of the deep soft ground and increases the tip resistance of the static electronic piezo-cone penetration test. Additionally, the pressure of the pore water decreases because the pore water is evaporated due to the ground heating. As a result of the experiment, it was verified that there was an improvement in the effect of deep soft ground by the ground heating method. With ground heating for 96 h, the tip resistance was increased by 61% at a point 0.35 m horizontally away from the electric heat pipe, 22% at 0.97 m, and 2% at 1.31 m. As a result of the field test, it was found that there were no problems in the power supply of the diesel generator and the control panel. It was easy to install the electric heating pipes in the deep soft ground. However, due to boring, the ground was disturbed and water vapor was discharged through this gap. To minimize the discharge of water vapor, it is necessary to drive the electric heating pipe.

  20. Experimental and numerical examination of eddy (Foucault) currents in rotating micro-coils: Generation of heat and its impact on sample temperature

    Science.gov (United States)

    Aguiar, Pedro M.; Jacquinot, Jacques-François; Sakellariou, Dimitris

    2009-09-01

    The application of nuclear magnetic resonance (NMR) to systems of limited quantity has stimulated the use of micro-coils (diameter Foucault (eddy) currents, which generate heat. We report the first data acquired with a 4 mm MACS system and spinning up to 10 kHz. The need to spin faster necessitates improved methods to control heating. We propose an approximate solution to calculate the power losses (heat) from the eddy currents for a solenoidal coil, in order to provide insight into the functional dependencies of Foucault currents. Experimental tests of the dependencies reveal conditions which result in reduced sample heating and negligible temperature distributions over the sample volume.

  1. Experimental and numerical examination of eddy (Foucault) currents in rotating micro-coils: Generation of heat and its impact on sample temperature.

    Science.gov (United States)

    Aguiar, Pedro M; Jacquinot, Jacques-François; Sakellariou, Dimitris

    2009-09-01

    The application of nuclear magnetic resonance (NMR) to systems of limited quantity has stimulated the use of micro-coils (diameter Foucault (eddy) currents, which generate heat. We report the first data acquired with a 4mm MACS system and spinning up to 10kHz. The need to spin faster necessitates improved methods to control heating. We propose an approximate solution to calculate the power losses (heat) from the eddy currents for a solenoidal coil, in order to provide insight into the functional dependencies of Foucault currents. Experimental tests of the dependencies reveal conditions which result in reduced sample heating and negligible temperature distributions over the sample volume.

  2. Ground-source heat pump case studies and utility programs

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.; Boyd, T.L.; Rogers, R.L.

    1995-04-01

    Ground-source heat pump systems are one of the promising new energy technologies that has shown rapid increase in usage over the past ten years in the United States. These systems offer substantial benefits to consumers and utilities in energy (kWh) and demand (kW) savings. The purpose of this study was to determine what existing monitored data was available mainly from electric utilities on heat pump performance, energy savings and demand reduction for residential, school and commercial building applications. In order to verify the performance, information was collected for 253 case studies from mainly utilities throughout the United States. The case studies were compiled into a database. The database was organized into general information, system information, ground system information, system performance, and additional information. Information was developed on the status of demand-side management of ground-source heat pump programs for about 60 electric utility and rural electric cooperatives on marketing, incentive programs, barriers to market penetration, number units installed in service area, and benefits.

  3. Proposed Design Procedure of a Helical Coil Heat Exchanger for an Orc Energy Recovery System for Vehicular Application

    Directory of Open Access Journals (Sweden)

    Giacomo Bonafoni

    2015-05-01

    Full Text Available There are several systems that produce energy from low grade heat sources such as Stirling engines, thermoelectric generators, and ORC (Organic Rankine Cycle systems. This paper shows the heat recovery from exhaust gases of a 1400 cc Diesel engine, to vaporize the working fluid of a small (<10 kW ORC system. The main objective is to have a system as compact as possible, to make it suitable for transport applications such as cars, ships, trains, etc. Three fluids were studied for this application: water and two refrigerant fluids: R134a and R245fa, which were found to be more appropriate than water at certain pressure and temperature values. Afterwards, a design procedure was proposed, then the heat exchanger was modeled and finally a steady-state thermal and structural analysis were carried out using a commercial software to find the temperature and the effects of the thermal stress on the material of the helical coiled tube.

  4. Hourly simulation of a Ground-Coupled Heat Pump system

    Science.gov (United States)

    Naldi, C.; Zanchini, E.

    2017-01-01

    In this paper, we present a MATLAB code for the hourly simulation of a whole Ground-Coupled Heat Pump (GCHP) system, based on the g-functions previously obtained by Zanchini and Lazzari. The code applies both to on-off heat pumps and to inverter-driven ones. It is employed to analyse the effects of the inverter and of the total length of the Borehole Heat Exchanger (BHE) field on the mean seasonal COP (SCOP) and on the mean seasonal EER (SEER) of a GCHP system designed for a residential house with 6 apartments in Bologna, North-Center Italy, with dominant heating loads. A BHE field with 3 in line boreholes is considered, with length of each BHE either 75 m or 105 m. The results show that the increase of the BHE length yields a SCOP enhancement of about 7%, while the SEER remains nearly unchanged. The replacement of the on-off heat pump by an inverter-driven one yields a SCOP enhancement of about 30% and a SEER enhancement of about 50%. The results demonstrate the importance of employing inverter-driven heat pumps for GCHP systems.

  5. Ground Source Heat Supply in Moscow Oblast: Temperature Potential and Sustainable Depth of Heat Wells

    Science.gov (United States)

    Vasil'ev, G. P.; Gornov, V. F.; Dmitriev, A. N.; Kolesova, M. V.; Yurchenko, V. A.

    2018-01-01

    The paper is devoted to a problem of increasing the efficiency of low-potential geothermal heat in heat pump systems of residential buildings the Moscow oblast of Russia, including Moscow. Estimates of a natural geothermal potential in the Moscow oblast (based on climatological data for the period from 1982 to 2011) are presented and a "Typical climatic year of natural soil temperature variations for the geoclimatic conditions of the Moscow oblast, including the city of Moscow" is proposed. Numerical simulation of the influence of geothermal energy potential and the depth of heat wells on the efficiency of ground source heat pump systems for the heat supply of residential buildings is carried out. Analysis of the numerical simulation showed that the operation of a heat pump system in a house heating mode under the geoclimatic conditions of the Moscow oblast leads to a temperature drop of the heat-exchange medium circulating through heat wells to 5-6°C by the end of the first 10 years of operation, and the process stabilizes by the 15th year of operation, and further changes in the heat-exchange medium temperature do not any longer significantly affect the temperature of the heat-exchange medium in the heat well. In this case, the exact dependence of the heat-exchange medium temperature drop on the depth is not revealed. Data on the economically expedient heat well depth for the conditions of the Moscow oblast ensuring a net present value for the whole residential building life cycle are presented. It is found that the heat well depth of 60 m can be considered as an endpoint for the Moscow oblast, and a further heat well deepening is economically impractical.

  6. Horizontal Parallel Pipe Ground Heat Exchanger : Analytical Conception and Experimental Study

    International Nuclear Information System (INIS)

    Naili, Nabiha; Jemli, Ramzi; Farhat, Abdel Hamid; Ben Nasrallah, Sassi

    2009-01-01

    Due to limited amount of natural resources exploited for heating, and in order to reduce the environmental impact, people should strive to use renewable energy resources. Ambient low-grade energy may be upgraded by the ground heat exchanger (GH E), which exploits the ground thermal inertia for buildings heating and cooling. In this study, analytical performance and experiments analysis of a horizontal ground heat exchanger have been performed. The analytical study, relates to the dimensioning of the heat exchanger, shows that the heat exchanger characteristics are very important for the determination of heat extracted from ground. The experimental results were obtained during the period 30 November to 10 December 2007, in the heating season of the greenhouses. Measurements show that the ground temperature under a certain depth remains relatively constant. To exploit effectively the heat capacity of the ground, a horizontal heat exchanger system has to be constructed and tested in the Center of Research and Technology of Energy, in Tunisia

  7. Cooling and dehumidifying coils

    International Nuclear Information System (INIS)

    Murthy, M.V.K.

    1988-01-01

    The operating features of cooling and dehumidifying coils and their constructional details are discussed. The heat transfer relations as applicable to the boiling refrigerant and a single phase fluid are presented. Methods of accounting for the effect of moisture condensation on the air side heat transfer coefficient and the fin effectiveness are explained. The logic flow necessary to analyze direct expansion coils and chilled water coils is discussed

  8. Impact of Seasonal Heat Accumulation on Operation of Geothermal Heat Pump System with Vertical Ground Heat Exchanger

    Science.gov (United States)

    Timofeev, D. V.; Malyavina, E. G.

    2017-11-01

    The subject of the investigation was to find out the influence of heat pump operation in summer on its function in winter. For this purpose a mathematical model of a ground coupled heat pump system has been developed and programmed. The mathematical model of a system ground heat exchanger uses the finite difference method to describe the heat transfer in soil and the analytical method to specify the heat transfer in the U-tubes heat exchanger. The thermal diffusivity by the heat transfer in the soil changes during gradual freezing of the pore moisture and thus slows soil freezing. The mathematical model of a heat pump includes the description of a scroll compressor and the simplified descriptions of the evaporator and condenser. The analysis showed that heating during the cold season and cooling in the warm season affect the average heat transfer medium temperature in the soil loop in the winter season. It has been also showed that the degree of this effect depends on the clay content in the soil.

  9. Measurement of cooling coil film heat transfer coefficient with polymer reaction proceeding in a stirred batch reactor; Jugo sonai ni okeru hanno shinko ni tomonau reikyaku coil no kyomaku netsudentatsu keisu no keiji henka

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, K [Soken Chemical and Engineering Co. Ltd., Saitama (Japan); Nishi, K; Kaminoyama, M; Kamiwano, M [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1996-09-10

    In radical additional solution polymerization, the viscosity increases with reaction progress. It is important to evaluate beforehand the cooling capacity of the reactor, which worsens with the process. In this study, a stirred batch reactor with both a paddle and a helical screw impeller were studied, and measurements were made for the dynamic changes of the film heat transfer coefficient of the cooling coil with progress of the polymer reaction. We found the change could be evaluated by the calculating heat balance of the generated heat, the viscous dissipation energy and the sensible heat change under conditions of monomer conversion and changing viscosity. 11 refs., 7 figs.

  10. Comparative Study of Heat Transfer from Nb-Ti and Nb$_3$Sn coils to He II

    CERN Document Server

    La China, M

    2008-01-01

    In superconducting magnets, the energy deposited or generated in the coil must be evacuated to prevent temperature rise and consequent transition of the superconductor to the resistive state. The main barrier to heat extraction is represented by the electric insulation wrapped around superconducting cables. In the LHC, insulation improvement is a key point in the development of interaction region magnets and injector chain fast-pulsed magnets for luminosity upgrade; the high heat load of these magnets, in fact, is not compatible with the use of current insulation schemes. We review the standard insulation schemes for Nb-Ti and Nb$_{3}$Sn technology from the thermal point of view. We implement, in an analytical model, the strongly nonlinear thermal resistances of the different coil components including the permeability to superfluid helium of Nb-Ti insulations, measured during the LHC main dipole development. We use such a model to compare Nb-Ti and Nb$_{3}$Sn technologies by taking into account their specific...

  11. A feasible system integrating combined heating and power system with ground-source heat pump

    International Nuclear Information System (INIS)

    Li, HongQiang; Kang, ShuShuo; Yu, Zhun; Cai, Bo; Zhang, GuoQiang

    2014-01-01

    A system integrating CHP (combined heating and power) subsystem based on natural gas and GSHP (ground-source heat pump subsystem) in series is proposed. By help of simulation software-Aspen Plus, the energy performance of a typical CHP and GSHP-S (S refers to ‘in series’) system was analyzed. The results show that the system can make a better use of waste heat in flue gas from CHP (combined heating and power subsystem). The total system energy efficiency is 123% and the COP (coefficient of performance) of GSHP (ground-source heat pump) subsystem is 5.3. A referenced CHP and GSHP-P (P refers to ‘in parallel’) system is used for comparison; its total system energy efficiency and COP of GSHP subsystem are 118.6% and 3.5 respectively. Compared with CHP and GSHP-P system with different operating parameters, the CHP and GSHP-S system can increase total system energy efficiency by 0.8–34.7%, with related output ratio of heat to power (R) from 1.9 to 18.3. Furthermore, the COP of GSHP subsystem can be increased between the range 3.6 and 6, which is much higher than that in conventional CHP and GSHP-P system. This study will be helpful for other efficient GSHP systems integrating if there is waste heat or other heat resources with low temperature. - Highlights: • CHP system based on natural gas and ground source heat pump. • The new system can make a better utilization of waste heat in flue gas by a special way. • The proposed system can realize energy saving potential from 0.8 to 34.7%. • The coefficient of performance of ground source heat pump subsystem is significantly improved from 3.5 to 3.6–6. • Warm water temperature and percentage of flue gas used to reheat are key parameters

  12. Simulation and experiment on the thermal performance of U-vertical ground coupled heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xinguo; Chen, Zhihao; Zhao, Jun [Department of Thermal Engineering, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China)

    2006-10-15

    This paper presented both the numerical simulations and experiments on the thermal performance of U-vertical ground coupled heat exchanger (UGCHE). The variation of the ground temperature and heat balance of the system were analyzed and compared in different operation modes in the numerical simulation. Experiments on the operation performance of the ground-coupled heat pump (GCHP) with the UGCHE were carried out. It shows that the ground source can be used as the heat source/sink for GCHP systems to have higher efficiency in saving energy. To preserve the ground resource for the sustainable utilization as heat source/sink, the heat emitted to ground and heat extracted from ground should be balanced. (author)

  13. Evaluation of a ground thermal energy storage system for heating and cooling of an existing dwelling

    Energy Technology Data Exchange (ETDEWEB)

    Leong, W.H; Lawrence, C.J. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Dept. of Mechanical and Industrial Engineering; Tarnawski, V.R. [Saint Mary' s Univ., Halifax, NS (Canada). Dept. of Engineering; Rosen, M.A. [University of Ontario Institute of Technology, Oshawa, ON (Canada). Faculty of Engineering and Applied Science

    2006-07-01

    A ground-coupled heat pump (GCHP) system for heating and cooling a residential house in Ontario was simulated. The system uses the surface ground as a thermal energy storage for storing thermal energy in the summer for later use in the winter. In the summer, the ground receives both solar energy and the heat rejected by the system during cooling operation. The relationship between a heat pump and the ground is a ground heat exchanger (GHE). This presentation described the vertical and horizontal configurations of the GHE, which are the 2 basic configurations. It also described the modelling and analysis of the GCHP system. The modelling involved both simplified and comprehensive models. The simplified models of heating and cooling loads of a building, a heat pump unit, and heat transfer at the ground heat exchanger provided a direct link to the comprehensive model of heat and moisture transfer in the ground, based on the finite element method. This combination of models provided an accurate and practical simulation tool for GCHP systems. The energy analysis was used to evaluate the performance of the system. The use of a horizontal ground heat exchanging pipe and the impact of heat deposition and extraction through it in the ground were also studied with reference to the length of pipe, depth of pipe and layout of the pipe loop. The objective of the analysis was to find ways to optimize the thermal performance of the system and environmental sustainability of the ground. 14 refs., 3 tabs., 5 figs.

  14. Coupling and power transfer efficiency enhancement of modular and array of planar coils using in-plane ring-shaped inner ferrites for inductive heating applications

    Science.gov (United States)

    Kilic, V. T.; Unal, E.; Demir, H. V.

    2017-07-01

    We propose and demonstrate a highly effective method of enhancing coupling and power transfer efficiency in inductive heating systems composed of planar coils. The proposed method is based on locating ring-shaped ferrites in the inner side of the coils in the same plane. Measurement results of simple inductive heating systems constructed with either a single or a pair of conventional circular coils show that, with the in-plane inner ferrites, the total dissipated power of the system is increased by over 65%. Also, with three-dimensional full electromagnetic solutions, it is found that power transfer efficiency of the system is increased up to 92% with the inner ferrite placement. The proposed method is promising to be used for efficiency enhancement in inductive heating applications, especially in all-surface induction hobs.

  15. Flow pattern-based mass and heat transfer and frictional drag of gas-non-Newtonian liquid flow in helical coil: two- and three-phase systems

    Science.gov (United States)

    Thandlam, Anil Kumar; Das, Chiranjib; Majumder, Subrata Kumar

    2017-04-01

    Investigation of wall-liquid mass transfer and heat transfer phenomena with gas-Newtonian and non-Newtonian fluids in vertically helical coil reactor have been reported in this article. Experiments were conducted to investigate the effect of various dynamic and geometric parameters on mass and heat transfer coefficients in the helical coil reactor. The flow pattern-based heat and mass transfer phenomena in the helical coil reactor are highlighted at different operating conditions. The study covered a wide range of geometric parameters such as diameter of the tube ( d t ), diameter of the coil ( D c ), diameter of the particle ( d p ), pitch difference ( p/D c ) and concentrations of non-Newtonian liquid. The correlation models for the heat and mass transfer coefficient based on the flow pattern are developed which may be useful in process scale-up of the helical coil reactor for industrial application. The frictional drag coefficient was also estimated and analyzed by mass transfer phenomena based on the electrochemical method.

  16. Study of the Tokamak-15 Superconducting Toroidal Field Coil (STFC) heating under the quench

    International Nuclear Information System (INIS)

    Anashkin, I.O.; Kabanovsky, S.V.; Chudnovsky, A.N.; Khvostenko, P.P.; Vertiporokh, A.N.; Ivanov, D.P.; Posadsky, I.A.

    1994-01-01

    Experiments in Tokamak-15 were performed to study the STFC heating under the quench. The quench was specially caused by current introduction into STFC at the unchanged input helium temperature. The experimental results and simulation data on temperature heating and amount of heat realized in the pancakes under the quench are given. In the experiments was shown that quench occurs in the internal turns of pancakes and estimations of maximal temperature heating corresponds to calculated ones

  17. An experimental study on the thermal and fouling characteristics in a washable shell and helically coiled heat exchanger by the Wilson plot method

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Kyoung Min; Ahn, Young Chull [Pusan National University, Busan (Korea, Republic of); Hwang, Jun Hyeon; Hur, Hyun; Na, Byung Chul; Hwang, Yoon Jae; Kim, Byung Soon [LG Electronics, Changwon (Korea, Republic of); Lee, Jae Keun [EcoEnergy Research Institute, Busan (Korea, Republic of)

    2016-06-15

    Brazed plate heat exchangers (BPHEX) are broadly used in water source heat pump systems for their large heat transfer capacity. Despite their high heat transfer rate, their high-performance rate tends to decrease sharply, due to fouling and they cannot be cleaned. So the thermal and fouling resistances of washable Shell and helically coiled tube heat exchangers (SCHEX) are designed and experimentally investigated in this study. Heat exchangers with two different tube types are studied and compared with a brazed plate heat exchanger. The overall thermal resistance coefficient of the heat exchangers as determined by using Wilson plots is 38% lower than that of the brazed plate heat exchanger at a Reynolds number of 2460. Fouling test results revealed that regular maintenance and physical cleaning can be used to maintain the thermal resistance of fouling of the washable heat exchanger at a level equal to or less than that of the brazed plate heat exchanger.

  18. Large coil task and results of testing US coils

    International Nuclear Information System (INIS)

    Haubenreich, P.N.

    1986-01-01

    The United States, EURATOM, Japan, and Switzerland have collaborated since 1978 in development of superconducting toroidal field coils for fusion reactor applications. The United States provided a test facility nd three coils; the other participants, one coil each. All coils have the same interface dimensions and performance requirements (stable at 8 T), but internal design was decided by each team. Two US coil teams chose bath-cooled NbTi, 10-kA conductors. One developed a Nb 3 Sn conductor, cooled by internal flow, rated at 18 kA. All US coils have diagnostic instrumentation and imbedded heaters that enable stability tests and simulated nuclear heating experiments. In single-coil tests, each coil operated at full current in self-field (6.4 T). In six-coil tests that began in July 1986, one US coil and the Japanese coil hve been successfully operated at full current at 8 T. The other coils have operated as background coils while awaiting their turn as test coil. Coil tests have been informative and results gratifying. The facility has capably supported coil testing and its operation has provided information that will be useful in designing future fusion systems. Coil capabilities beyond nominal design points will be determined

  19. Friction pressure drop and heat transfer coefficient of two-phase flow in helically coiled tube once-through steam generator for integrated type marine water reactor

    International Nuclear Information System (INIS)

    Nariai, Hideki; Kobayashi, Michiyuki; Matsuoka, Takeshi.

    1982-01-01

    Two-phase friction pressure drop and heat transfer coefficients in a once-through steam generator with helically coiled tubes were investigated with the model test rig of an integrated type marine water reactor. As the dimensions of the heat transfer tubes and the thermal-fluid conditions are almost the same as those of real reactors, the data applicable directly to the real reactor design were obtained. As to the friction pressure drop, modified Kozeki's prediction which is based on the experimental data by Kozeki for coiled tubes, agreed the best with the experimental data. Modified Martinelli-Nelson's prediction which is based on Martinelli-Nelson's multiplier using Ito's equation for single-phase flow in coiled tube, agreed within 30%. The effect of coiled tube on the average heat transfer coefficients at boiling region were small, and the predictions for straight tube could also be applied to coiled tube. Schrock-Grossman's correlation agreed well with the experimental data at the pressures of lower than 3.5 MPa. It was suggested that dryout should be occurred at the quality of greater than 90% within the conditions of this report. (author)

  20. Ground Source Integrated Heat Pump (GS-IHP) Development

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, V. D. [ORNL; Rice, K. [ORNL; Murphy, R. [ORNL; Munk, J. [ORNL; Ally, Moonis [ORNL; Shen, Bo [ORNL; Craddick, William [ORNL; Hearn, Shawn A. [ClimateMaster, Inc.

    2013-05-24

    Between October 2008 and May 2013 ORNL and ClimateMaster, Inc. (CM) engaged in a Cooperative Research and Development Agreement (CRADA) to develop a groundsource integrated heat pump (GS-IHP) system for the US residential market. A initial prototype was designed and fabricated, lab-tested, and modeled in TRNSYS (SOLAR Energy Laboratory, et al, 2010) to predict annual performance relative to 1) a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (combination of air-source heat pump (ASHP) and resistance water heater) and 2) a state-of-the-art (SOA) two-capacity ground-source heat pump with desuperheater water heater (WH) option (GSHPwDS). Predicted total annual energy savings, while providing space conditioning and water heating for a 2600 ft{sup 2} (242 m{sup 2}) house at 5 U.S. locations, ranged from 52 to 59%, averaging 55%, relative to the minimum efficiency suite. Predicted energy use for water heating was reduced 68 to 78% relative to resistance WH. Predicted total annual savings for the GSHPwDS relative to the same baseline averaged 22.6% with water heating energy use reduced by 10 to 30% from desuperheater contributions. The 1st generation (or alpha) prototype design for the GS-IHP was finalized in 2010 and field test samples were fabricated for testing by CM and by ORNL. Two of the alpha units were installed in 3700 ft{sup 2} (345 m{sup 2}) houses at the ZEBRAlliance site in Oak Ridge and field tested during 2011. Based on the steady-state performance demonstrated by the GS-IHPs it was projected that it would achieve >52% energy savings relative to the minimum efficiency suite at this specific site. A number of operational issues with the alpha units were identified indicating design changes needed to the system before market introduction could be accomplished. These were communicated to CM throughout the field test period. Based on the alpha unit test results and the diagnostic information coming from the field test

  1. Soil temperature distribution around a U-tube heat exchanger in a multi-function ground source heat pump system

    International Nuclear Information System (INIS)

    Li Shuhong; Yang Weihua; Zhang Xiaosong

    2009-01-01

    The imbalance of heat extracted from the earth by the underground heat exchangers in winter and ejected into it in summer is expected to affect the long term performance of conventional ground source heat pump (GSHP) in territories with a cold winter and a warm summer such as the middle and downstream areas of the Yangtze River in China. This paper presents a new multi-function ground source heat pump (MFGSHP) system which supplies hot water as well as space cooling/heating to mitigate the soil imbalance of the extracted and ejected heat by a ground source heat pump system. The heat transfer characteristic is studied and the soil temperature around the underground heat exchangers are simulated under a typical climatic condition of the Yangtze River. A three-dimensional model was constructed with the commercial computational fluid dynamics software FLUENT based on the inner heat source theory. Temperature distribution and variation trend of a tube cluster of the underground heat exchanger are simulated for the long term performance. The results show that the soil temperature around the underground tube keeps increasing due to the surplus heat ejected into the earth in summer, which deteriorates the system performance and may lead to the eventual system deterioration. The simulation shows that MFGSHP can effectively alleviate the temperature rise by balancing the heat ejected to/extracted from underground by the conventional ground source heat pump system. The new system also improves the energy efficiency.

  2. Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Xun Yang

    2017-08-01

    Full Text Available In this study, the dynamic melting process of the phase change material (PCM in a vertical cylindrical tube-in-tank thermal energy storage (TES unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF. A numerical model using the computational fluid dynamics (CFD approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

  3. In Vivo Radiofrequency Heating in Swine in a 3T (123.2 MHz) Birdcage Whole-Body Coil

    Science.gov (United States)

    Shrivastava, Devashish; Utecht, Lynn; Tian, Jinfeng; Hughes, John; Vaughan, J. Thomas

    2014-01-01

    Purpose To study in vivo radiofrequency (RF) heating produced due to power deposition from a 3T (Larmour frequency = 123.2 MHz), birdcage, whole-body coil. Methods The RF heating was simulated in a digital swine by solving the mechanistic generic bioheat transfer model (GBHTM) and the conventional, empirical Pennes bioheat transfer equation for the following two cases: (1) when the porcine head was in the isocenter, and (2) when the porcine trunk was in the isocenter. The simulation results were validated by making direct fluoroptic temperature measurements in the skin, brain, simulated hot regions, and rectum of ten swine (Case 1, N= 5, mean animal weight = 84.03 ± 6.85 kg, Whole-body average SAR = 2.65 ± 0.22 W/kg; Case 2, N= 5, mean animal weight = 81.59 ± 6.23 kg, Whole-body average SAR = 2.77 ± 0.26 W/kg) during one hour of exposure to a turbo spin echo sequence. Results The GBHTM simulated the RF heating more accurately compared to the Pennes equation. In vivo temperatures exceeded safe temperature thresholds with allowable SAR exposures. Hot regions may be produced deep inside the body, away from the skin. Conclusion SAR exposures to produce safe temperature thresholds may need re-investigation. PMID:24259413

  4. In vivo radiofrequency heating in swine in a 3T (123.2-MHz) birdcage whole body coil.

    Science.gov (United States)

    Shrivastava, Devashish; Utecht, Lynn; Tian, Jinfeng; Hughes, John; Vaughan, J Thomas

    2014-10-01

    To study in vivo radiofrequency (RF) heating produced due to power deposition from a 3T (Larmour frequency = 123.2 MHz), birdcage, whole body coil. The RF heating was simulated in a digital swine by solving the mechanistic generic bioheat transfer model (GBHTM) and the conventional, empirical Pennes bioheat transfer equation for two cases: 1) when the swine head was in the isocenter and 2) when the swine trunk was in the isocenter. The simulation results were validated by making direct fluoroptic temperature measurements in the skin, brain, simulated hot regions, and rectum of 10 swine (case 1: n = 5, mean animal weight = 84.03 ± 6.85 kg, whole body average SAR = 2.65 ± 0.22 W/kg; case 2: n = 5, mean animal weight = 81.59 ± 6.23 kg, whole body average SAR = 2.77 ± 0.26 W/kg) during 1 h of exposure to a turbo spin echo sequence. The GBHTM simulated the RF heating more accurately compared with the Pennes equation. In vivo temperatures exceeded safe temperature thresholds with allowable SAR exposures. Hot regions may be produced deep inside the body, away from the skin. SAR exposures that produce safe temperature thresholds need reinvestigation. Copyright © 2013 Wiley Periodicals, Inc.

  5. Simulation of hybrid ground-coupled heat pump with domestic hot water heating systems using HVACSIM+

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Ping; Yang, Hongxing [Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong (China); Spitler, Jeffrey D. [School of Mechanical Engineering, Oklahoma State University (United States); Fang, Zhaohong [Ground Source Heat Pump Research Center, Shandong University of Architecture and Engineering, Jinan (China)

    2008-07-01

    A hybrid ground-coupled heat pump (HGCHP) with domestic hot water (DHW) supply system has been proposed in this paper for space cooling/heating and DHW supply for residential buildings in hot-climate areas. A simulation model for this hybrid system is established within the HVACSIM+ environment. A sample system, applied for a small residential apartment located in Hong Kong, is hourly simulated in a typical meteorological year. The conventional GCHP system and an electric heater for DHW supply are also modeled and simulated on an hourly basis within the HVACSIM+ for comparison purpose. The results obtained from this case study show that the HGCHP system can effectively alleviate the imbalanced loads of the ground heat exchanger (GHE) and can offer almost 95% DHW demand. The energy saving for DHW heating is about 70% compared with an electric heater. This proposed scheme, i.e. the HGCHP with DHW supply, is suitable to residential buildings in hot-climate areas, such as in Hong Kong. (author)

  6. Ground source heat pump performance in case of high humidity soil and yearly balanced heat transfer

    International Nuclear Information System (INIS)

    Schibuola, Luigi; Tambani, Chiara; Zarrella, Angelo; Scarpa, Massimiliano

    2013-01-01

    Highlights: • GSHPs are simulated in case of humid soil and yearly balanced heat transfer. • Humid soil and yearly balanced heat transfer imply higher compactness of GSHPs. • Resulting GSHPs are compared with other traditional and innovative HVAC systems. • GSHPs score best, especially in case of inverter-driven compressors. - Abstract: Ground source heat pump (GSHP) systems are spreading also in Southern Europe, due to their high energy efficiency both in heating and in cooling mode. Moreover, they are particularly suitable in historical cities because of difficulties in the integration of heating/cooling systems into buildings subjected to historical preservation regulations. In these cases, GSHP systems, especially the ones provided with borehole heat exchangers, are a suitable solution instead of gas boilers, air-cooled chillers or cooling towers. In humid soils, GSHP systems are even more interesting because of their enhanced performance due to higher values of soil thermal conductivity and capacity. In this paper, GSHP systems operating under these boundary conditions are analyzed through a specific case study set in Venice and related to the restoration of an historical building. With this analysis the relevant influences of soil thermal conductivity and yearly balanced heat transfer in the design of the borehole field are shown. In particular, the paper shows the possibility to achieve higher compactness of the borehole field footprint area when yearly balanced heat transfer in the borehole field is expected. Then, the second set of results contained in the paper shows how GSHP systems designed for high humidity soils and yearly balanced heat loads at the ground side, even if characterized by a compact footprint area, may still ensure better performance than other available and more common technologies such as boilers, air-cooled chillers, chillers coupled with cooling towers and heat pumps and chillers coupled with lagoon water. As a consequence

  7. A study of the reverse cycle defrosting performance on a multi-circuit outdoor coil unit in an air source heat pump – Part I: Experiments

    International Nuclear Information System (INIS)

    Qu, Minglu; Xia, Liang; Deng, Shiming; Jiang, Yiqiang

    2012-01-01

    Highlights: ► We experimental study the defrosting performance on a multi-circuit outdoor coil unit in an ASHP unit. ► We find that defrosting is quicker on the airside of upper circuits than that on the lower circuits. ► We discuss the effects of downwards flowing of the melted frost along the outdoor coil surface on defrosting performance. -- Abstract: When an air source heat pump (ASHP) unit operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil which normally has multiple parallel circuits on its refrigerant side for minimized refrigerant pressure loss and enhanced heat transfer efficiency. On its airside, however, there is usually no segmentation corresponding to the number of refrigerant circuit. Frosting deteriorates the operation and energy efficiency of the ASHP unit and periodic defrosting becomes necessary. Currently the most widely used standard defrosting method for ASHPs is reverse cycle defrost. This paper, the first part of a two-part series, reports on the experimental part of a study of the reverse cycle defrosting performance on a multi-circuit outdoor coil unit in an experimental 6.5 kW heating capacity residential ASHP unit. Firstly the experimental ASHP unit is described and experimental procedures detailed. Secondly, the experimental results are reported. This is followed by the discussion on the effects of downwards flowing of the melted frost along a multi-circuit outdoor coil surface on defrosting performance. Finally, the evaluation of the defrosting efficiency for the experimental ASHP unit is provided. In the second part of the series, a modeling analysis on the effects of downwards flowing of the melted frost along the multi-circuit outdoor coil surface on defrosting performance of the experimental ASHP unit will be presented.

  8. Ground surface temperature and continental heat gain: uncertainties from underground

    International Nuclear Information System (INIS)

    Beltrami, Hugo; Matharoo, Gurpreet S; Smerdon, Jason E

    2015-01-01

    Temperature changes at the Earth's surface propagate and are recorded underground as perturbations to the equilibrium thermal regime associated with the heat flow from the Earth's interior. Borehole climatology is concerned with the analysis and interpretation of these downward propagating subsurface temperature anomalies in terms of surface climate. Proper determination of the steady-state geothermal regime is therefore crucial because it is the reference against which climate-induced subsurface temperature anomalies are estimated. Here, we examine the effects of data noise on the determination of the steady-state geothermal regime of the subsurface and the subsequent impact on estimates of ground surface temperature (GST) history and heat gain. We carry out a series of Monte Carlo experiments using 1000 Gaussian noise realizations and depth sections of 100 and 200 m as for steady-state estimates depth intervals, as well as a range of data sampling intervals from 10 m to 0.02 m. Results indicate that typical uncertainties for 50 year averages are on the order of ±0.02 K for the most recent 100 year period. These uncertainties grow with decreasing sampling intervals, reaching about ±0.1 K for a 10 m sampling interval under identical conditions and target period. Uncertainties increase for progressively older periods, reaching ±0.3 K at 500 years before present for a 10 m sampling interval. The uncertainties in reconstructed GST histories for the Northern Hemisphere for the most recent 50 year period can reach a maximum of ±0.5 K in some areas. We suggest that continuous logging should be the preferred approach when measuring geothermal data for climate reconstructions, and that for those using the International Heat Flow Commission database for borehole climatology, the steady-state thermal conditions should be estimated from boreholes as deep as possible and using a large fitting depth range (∼100 m). (letter)

  9. Production of an aluminium heat exchanger coil; Fertigung eines gewickelten Waermetauschers aus Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, G. [Linde AG, Tacherting (Germany)

    2002-07-01

    The heat exchangers presented in this contribution are the liquefier and subcooler of a two-component natural gas liquefaction plant to be exported to Australia, with a total heat exchanger surface that corresponds to the area of 8 soccer fields. [German] Bei den vorgestellten Waermetauschern handelt es sich um Liquefier und Subcooler einer aus 2 Prozesseinheiten bestehenden Erdgasverfluessigungsanlage fuer Australien, mit einer Gesamt-Waermeaustauschflaeche vergleichbar mit der Groesse von 8 Fussballfeldern. (orig.)

  10. Development of a helium/helium intermediate heat exchanger with helical coil tube bundle

    International Nuclear Information System (INIS)

    Czimczik, A.; Hirschle, G.

    1984-01-01

    Besides the research and development work leading to the design basis for the reference heat exchanger, the stages of development up to the realisation of a nuclear He/He intermediate heat exchanger (IHX) include selected experiments in manufacturing techniques and with individual test components, as well as the design, fabrication and testing of representative prototype component. The process of manufacturing and experiences gained so far are described

  11. The application of ground source heat pumps to a subdivision-wide district heating system

    International Nuclear Information System (INIS)

    Ciavaglia, L.

    2005-01-01

    Design guidelines for economic ground source heat pumps (GSHP) in district energy systems were presented. The broad economics of using central GSHP in a community district energy system were examined. Design parameters needed to utilize GSHP in district energy system were outlined. The sensitivity of energy prices and the costs of major capital were reviewed. District heating load duration curves were outlined. It was suggested that varying GSHP capacity from 0 to 100 per cent of load was advisable. In addition, capacity should be balanced with gas boiler technology. The amortizing of capital within energy costs was recommended. It was suggested that the best scenario was a minimum of 50 per cent ground energy. Details of pipings and heat exchanger costs were presented, along with costs for gas boilers and gas costs for the district energy system. Charts of current costing and reduction of piping capital were included. It was concluded that GSHP can be a viable component of a district energy system, as a GSHP based district energy system can provide more stable energy prices than conventional fossil fuel systems. It was suggested that sizing of GSHP at, or near, 40 per cent of peak demand provided optimal conditions with respect to energy cost and use of earth energy. tabs., figs

  12. Supporting device for Toroidal coils

    International Nuclear Information System (INIS)

    Araki, Takao.

    1985-01-01

    Purpose: To reduce the response of a toroidal coil supporting device upon earthquakes and improve the earthquake proofness in a tokamak type thermonuclear device. Constitution: Structural materials having large longitudinal modulus and enduring great stresses, for example, stainless steels are used as the toroidal coil supporting legs and heat insulating structural materials are embedded in a nuclear reactor base mats below the supporting legs. Furthermore, heat insulating concretes are spiked around the heat insulating structural materials to prevent the intrusion of heat to the toroidal coils. The toroidal coils are kept at cryogenic state and superconductive state for the conductors. In this way, the period of proper vibrations of the toroidal coils and the toroidal coil supporting structures can be shortened thereby decreasing the seismic response. Furthermore, since the strength of the supporting legs is increased, the earthquake proofness of the coils can be improved. (Kamimura, M.)

  13. The influence of a vertical ground heat exchanger length on the electricity consumption of the heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Michopoulos, A.; Kyriakis, N. [Process Equipment Design Laboratory, Mechanical Engineer Department, Aristotle University of Thessaloniki (AUTh), P.O. Box 487, 541 24 Thessaloniki (Greece)

    2010-07-15

    The use of heat pumps combined with vertical ground heat exchangers for heating and cooling of buildings, has significantly gained popularity in recent years. The design method for these systems, as it is proposed by ASHRAE, is taking into account the maximum thermal and cooling loads of the building, the thermophysical properties of the soil at the area of installation and a minimum Coefficient of Performance (COP) of the heat pumps. This approach usually results in larger than needed length of the ground heat exchanger, thus increasing the installation cost. A new analytical simulation tool, capable to determine the required ground heat exchanger length has been developed at the Process Equipment Design Laboratory (PEDL) of the AUTh. It models the function of the system as a whole over long time periods, e.g. 20 years, using as input parameters the thermal and cooling loads of the building, the thermophysical properties of the borehole and the characteristic curves of the heat pumps. The results include the electricity consumption of the heat pumps and the heat absorbed from or rejected to the ground. The aim of this paper is to describe the developed simulation algorithm and present the results of such a simulation in a case study. It is proved that the total required length of the ground heat exchanger is less than that calculated using the common numerical method. (author)

  14. Ground source heat pumps (GSHP) for heating and cooling in Greece

    Science.gov (United States)

    Dimera, Nikoletta

    This report presents the results of a theoretical study about the feasibility of closed loop Ground Source Heat Pumps (GSHP) for heating and cooling in Greece in terms of their impact on the capital and running costs of the building services systems of the buildings. The main aim of carrying out this study was to investigate if the heating and cooling potential of the ground could be utilized cost efficiently to serve the buildings energy demand in the Greek region. At first, an existing implementation of a closed loop GSHP system in Greece is presented and its efficiency is discussed. The aim of doing so was to understand the way of sizing such systems and the efficiency of this technology in Greek climatic and ground conditions. In a separate part of this report, the impact of different user behaviour and of various ways of sizing a GSHP system is investigated in terms of the cost impact of the examined different options as well as of their effect on the internal health and comfort conditions. After the building simulation under different scenarios, it was concluded that the user behavior - the operation of windows mostly - can result in great savings on the annual energy bills. The conclusions of this first part of the report about the user behaviour and the way of sizing GSHP systems were utilized in the next part of it, where a GSHP system is proposed for a building currently under construction in central Greece. A simple 30-year cost analysis was used in order to estimate the performance of the proposed GSHP system in economic terms and to compare it with the conventional HVAC system commonly used in Greece. According to the results of the analysis, the capital cost of installing a GSHP system for heating and cooling in buildings in Greece appears higher than the cost of conventional HVAC systems. More specifically, the capital cost of an installation for heating including gas boilers and a cooling system based on air conditioning split units is about the

  15. Efficient Arrangement of Field Coils for Rotational Induction Heating of Nonmagnetic Cylindrical Billets

    Czech Academy of Sciences Publication Activity Database

    Donátová, M.; Karban, P.; Doležel, Ivo

    2010-01-01

    Roč. 86, č. 1 (2010), s. 83-85 ISSN 0033-2097 Grant - others:GA MŠk(CZ) MEB050807 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction heating * integrodifferential model * electromagnetic field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.242, year: 2010 http://pe.org.pl/

  16. Steady-state heat transfer to boiling liquid helium in simulated coil windings

    International Nuclear Information System (INIS)

    Walstrom, P.L.

    1981-01-01

    The present data show that the worst case steady-state stability in the GE/LCT magnet windings is at a horizontal conductor orientation. The heat transfer improves with inclination of the conductor from horizontal. Calculations show that for these small regions normal zones will recover by cold-end conduction from the inclined conductor on either end

  17. An analysis of solar assisted ground source heat pumps in cold climates

    International Nuclear Information System (INIS)

    Emmi, Giuseppe; Zarrella, Angelo; De Carli, Michele; Galgaro, Antonio

    2015-01-01

    Highlights: • The work focuses on solar assisted ground source heat pump in cold climates. • Multi-year simulations of SAGSHP, are carried out in six cold locations. • GSHP and SAGSHP are compared. • The effect of total borehole length on the heat pump energy efficiency is studied. • A dedicated control strategy is used to manage both solar and ground loops. - Abstract: Exploiting renewable energy sources for air-conditioning has been extensively investigated over recent years, and many countries have been working to promote the use of renewable energy to decrease energy consumption and CO_2 emissions. Electrical heat pumps currently represent the most promising technology to reduce fossil fuel usage. While ground source heat pumps, which use free heat sources, have been taking significant steps forward and despite the fact that their energy performance is better than that of air source heat pumps, their development has been limited by their high initial investment cost. An alternative solution is one that uses solar thermal collectors coupled with a ground source heat pump in a so-called solar assisted ground source heat pump. A ground source heat pump system, used to heat environments located in a cold climate, was investigated in this study. The solar assisted ground source heat pump extracted heat from the ground by means of borehole heat exchangers and it injected excess solar thermal energy into the ground. Building load profiles are usually heating dominated in cold climates, but when common ground source heat pump systems are used only for heating, their performance decreases due to an unbalanced ground load. Solar thermal collectors can help to ensure that systems installed in cold zones perform more efficiently. Computer simulations using a Transient System Simulation (TRNSYS) tool were carried out in six cold locations in order to investigate solar assisted ground source heat pumps. The effect of the borehole length on the energy efficiency of

  18. Performance analysis on a large scale borehole ground source heat pump in Tianjin cultural centre

    Science.gov (United States)

    Yin, Baoquan; Wu, Xiaoting

    2018-02-01

    In this paper, the temperature distribution of the geothermal field for the vertical borehole ground-coupled heat pump was tested and analysed. Besides the borehole ground-coupled heat pump, the system composed of the ice storage, heat supply network and cooling tower. According to the operation data for nearly three years, the temperature constant zone is in the ground depth of 40m -120m with a temperature gradient of about 3.0°C/100m. The temperature of the soil dropped significantly in the heating season, increased significantly in the cooling season, and reinstated in the transitional season. With the energy balance design of the heating and cooling and the existence of the soil thermal inertia, the soil temperature stayed in a relative stable range and the ground source heat pump system was operated with a relative high efficiency. The geothermal source heat pump was shown to be applicable for large scale utilization.

  19. Characterization of the effects of borehole configuration and interference with long term ground temperature modelling of ground source heat pumps

    International Nuclear Information System (INIS)

    Law, Ying Lam E.; Dworkin, Seth B.

    2016-01-01

    Highlights: • Long term ground temperature response is explored using finite element methods. • Simulation method is validated against experimental and analytical data. • Temperature changes at a fast rate in the first few years and slows down gradually. • ASHRAE recommended separation distances are not always sufficient. • Thermal accumulation occurs at the centre of borehole field. - Abstract: Ground source heat pumps (GSHPs) are an environmentally friendly alternative to conventional heating and cooling systems because of their high efficiency and low greenhouse gas emissions. The ground acts as a heat sink/source for the excess/required heat inside a building for cooling and heating modes, respectively. However, imbalance in heating and cooling needs can change ground temperature over the operating duration. This increase/decrease in ground temperature lowers system efficiency and causes the ground to foul—failing to accept or provide more heat. In order to ensure that GSHPs can operate to their designed conditions, thermal modelling is required to simulate the ground temperature during system operation. In addition, the borehole field layout can have a major impact on ground temperature. In this study, four buildings were studied—a hospital, fast-food restaurant, residence, and school, each with varying borehole configurations. Boreholes were modelled in a soil volume using finite-element methods and heating and cooling fluxes were applied to the borehole walls to simulate the GSHP operation. 20 years of operation were modelled for each building for 2 × 2, 4 × 4, and 2 × 8 borehole configurations. Results indicate that the borehole separation distance of 6 m, recommended by ASHRAE, is not always sufficient to prevent borehole thermal interactions. Benefits of using a 2 × 8 configuration as opposed to a 4 × 4 configuration, which can be observed because of the larger perimeter it provides for heat to dissipate to surrounding soil were

  20. Superconducting poloidal coils for STARFIRE commercial reactor

    International Nuclear Information System (INIS)

    Wang, S.T.; Evans, K. Jr.; Turner, L.R.; Huang, Y.C.; Prater, R.; Alcorn, J.

    1979-01-01

    STARFIRE is considered to be the tenth commercial tokamak power plant. A preliminary design study on its superconducting poloidal coil system is presented. Key features of the design studies are: the elimination of the ohmic heating coil; the trade-off studies of the equilibrium field coil locations; and the development of a conceptual design for the superconducting equilibrium field coils. Described are the 100 kA cryostable conductor design, the coil structure, and evaluation of the coil forces

  1. Thermodynamic optimization of ground heat exchangers with single U-tube by entropy generation minimization method

    International Nuclear Information System (INIS)

    Li Min; Lai, Alvin C.K.

    2013-01-01

    Highlights: ► A second-law-based analysis is performed for single U-tube ground heat exchangers. ► Two expressions for the optimal length and flow velocity are developed for GHEs. ► Empirical velocities of GHEs are large compared to thermodynamic optimum values. - Abstract: This paper investigates thermodynamic performance of borehole ground heat exchangers with a single U-tube by the entropy generation minimization method which requires information of heat transfer and fluid mechanics, in addition to thermodynamics analysis. This study first derives an expression for dimensionless entropy generation number, a function that consists of five dimensionless variables, including Reynolds number, dimensionless borehole length, scale factor of pressures, and two duty parameters of ground heat exchangers. The derivation combines a heat transfer model and a hydraulics model for borehole ground heat exchangers with the first law and the second law of thermodynamics. Next, the entropy generation number is minimized to produce two analytical expressions for the optimal length and the optimal flow velocity of ground heat exchangers. Then, this paper discusses and analyzes implications and applications of these optimization formulas with two case studies. An important finding from the case studies is that widely used empirical velocities of circulating fluid are too large to operate ground-coupled heat pump systems in a thermodynamic optimization way. This paper demonstrates that thermodynamic optimal parameters of ground heat exchangers can probably be determined by using the entropy generation minimization method.

  2. Experimental investigation of melting behavior of PCM by using coil heat source inside cylindrical container

    Directory of Open Access Journals (Sweden)

    M. Tayssir

    2017-05-01

    Experiments were performed for different inlet temperatures of HTF 70 °C, 80 °C and 90 °C and for different volume flow rates 5 lpm, 10 lpm and 15 lpm. The transient variation of the molten fraction, the percentage of thermal energy storage and the average Nusselt number are obtained. A significant effect of the inlet HTF temperature more than that of volume flow rate on the paraffin melting process is observed. Also, empirical correlation for the molten fraction and percentage of heat stored are deduced in terms of the operating conditions.

  3. Exergoeconomic analysis of a solar assisted ground-source heat pump greenhouse heating system

    International Nuclear Information System (INIS)

    Ozgener, Onder; Hepbasli, Arif

    2005-01-01

    EXCEM analysis may prove useful to investigators in engineering and other disciplines due to the methodology are being based on the quantities exergy, cost, energy and mass. The main objective of the present study is to investigate between capital costs and thermodynamic losses for devices in solar assisted ground-source heat pump greenhouse heating system (SAGSHPGHS) with a 50 m vertical 32 mm nominal diameter U-bend ground heat exchanger. This system was designed and installed at the Solar Energy Institute, Ege University, Izmir, Turkey. Thermodynamic loss rate-to-capital cost ratios are used to show that, for components and the overall system, a systematic correlation appears to exist between capital cost and exergy loss (total or internal), but not between capital cost and energy loss or external exergy loss. This correlation may imply that devices in successful air conditioning are configured so as to achieve an overall optimal design, by appropriately balancing the thermodynamic (exergy-based) and economic characteristics of the overall system and its devices. The results may, (i) provide useful insights into the relations between thermodynamics and economics, both in general and for SAGSHPGHS (ii) help demonstrate the merits of second-law analysis. It is observed from the results that the maximum exergy destructions in the system particularly occur due to the electrical, mechanical and isentropic efficiencies and emphasize the need for paying close attention to the selection of this type of equipment, since components of inferior performance can considerably reduce the overall performance of the system. In conjunction with this, the total exergy losses values are obtained to be from 0.010 kW to 0.480 kW for the system. As expected, the largest energy and exergy losses occur in the greenhouse and compressor. The ratio of thermodynamic loss rate to capital cost values are obtained for a range from 0.035 to 1.125

  4. Current status of ground source heat pumps and underground thermal energy storage in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Sanner, B. [Justus Liebig University, Giessen (Germany). Institute of Applied Geosciences; Karytsas, C.; Mendrinos, D. [Center for Renewable Energy Sources, Pikermi (Greece); Rybach, L. [Geowatt AG, Zurich (Switzerland)

    2003-12-01

    Geothermal Heat Pumps, or Ground Coupled Heat Pumps (GCHP), are systems combining a heat pump with a ground heat exchanger (closed loop systems), or fed by ground water from a well (open loop systems). They use the earth as a heat source when operating in heating mode, with a fluid (usually water or a water-antifreeze mixture) as the medium that transfers the heat from the earth to the evaporator of the heat pump, thus utilising geothermal energy. In cooling mode, they use the earth as a heat sink. With Borehole Heat Exchangers (BHE), geothermal heat pumps can offer both heating and cooling at virtually any location, with great flexibility to meet any demands. More than 20 years of R and D focusing on BUE in Europe has resulted in a well-established concept of sustainability for this technology, as well as sound design and installation criteria. Recent developments are the Thermal Response Test, which allows in-situ-determination of ground thermal properties for design purposes, and thermally enhanced grouting materials to reduce borehole thermal resistance. For cooling purposes, but also for the storage of solar or waste heat, the concept of underground thermal energy storage (UTES) could prove successful. Systems can be either open (aquifer storage) or can use BHE (borehole storage). Whereas cold storage is already established on the market, heat storage, and, in particular, high temperature heat storage (> 50{sup o}C) is still in the demonstration phase. Despite the fact that geothermal heat pumps have been in use for over 50 years now (the first were in the USA), market penetration of this technology is still in its infancy, with fossil fuels dominating the space heating market and air-to-air heat pumps that of space cooling. In Germany, Switzerland, Austria, Sweden, Denmark, Norway, France and the USA, large numbers of geothermal heat pumps are already operational, and installation guidelines, quality control and contractor certification are now major issues

  5. Ground water heat pumps and cooling with ground water basins as seasonal storage; Grundvandsvarmepumper og -koeling med grundvandsmagasiner som saesonlager

    Energy Technology Data Exchange (ETDEWEB)

    2008-04-15

    Ground water temperature is constant all the year round, in Denmark approximately 9 deg. C, which is ideal for a number of cooling purposes including cooling of buildings. The structures in which the ground water flows (sand, gravel and chalk) are efficient for storing coldness and heat over longer periods. By using seasonal storage of low-temperature heat and coldness in ground water layers close to the terrain it is feasible to reach profitable energy savings of up to 90% for cooling and heating of e.g. hotels, airports, shopping malls, office buildings and other larger buildings. At the same time the large energy savings means major reduction of CO{sub 2} emissions. (BA)

  6. Experimental performance analysis of a direct-expansion ground source heat pump in Xiangtan, China

    International Nuclear Information System (INIS)

    Yang, Wei

    2013-01-01

    The DX GSHP (direct-expansion ground source heat pump), which uses a buried copper piping network through which refrigerant is circulated, is one type of GSHP (ground source heat pump). This study investigates the performance characteristics of a vertical U-bend direct-expansion ground source (geothermal) heat pump system (DX GSHPS) for both heating and cooling. Compared with the conventional GCHP (ground coupled heat pump) system, the DX GSHP system is more efficient, with lower thermal resistance in the GHE (ground heat exchanger) and a lower (higher) condensing (evaporating) temperature in the cooling (heating) mode. In addition, the system performance of the whole DX GSHP system is also higher than that of the conventional GCHP system. A DX GSHP system in Xiangtan, China with a U-bend ground heat exchanger 42 m deep with a nominal outside diameter of 12.7 mm buried in a water well was tested and analysed. The results showed that the performance of this system is very high. The maximum (average) COPs of the system were found to be 6.08 (4.73) and 6.32 (5.03) in the heating and cooling modes, respectively. - Highlights: • The reasons for the higher performance of the DX GSHP (direct-expansion ground source heat pump) are analysed theoretically compared with the conventional GCHP (ground coupled heat pump). • The experimental performance of a DX GSHP system is investigated, which makes a valuable contribution to the literature. • The study is helpful in demonstrating the energy efficiency of the DX GSHP system

  7. Analysis and testing of the DIII-D ohmic heating coil lead repair clamp

    International Nuclear Information System (INIS)

    Reis, E.E.; Anderson, P.M.; Chin, E.; Robinson, J.I.

    1997-11-01

    DIII-D has been operating for the last year with limited volt-second capabilities due to structural failure of a conductor lead to one of the ohmic heating (OH) solenoids. The conductor failure was due to poor epoxy impregnation of the overwrap of the lead pack, resulting in copper fatigue and a water leak. A number of structural analyses were performed to assist in determining the failure scenario and to evaluate various repair options. A fatigue stress analysis of the leads with a failed epoxy overwrap indicated crack initiation after 1,000 cycles at the maximum operating conditions. The failure occurred in a very inaccessible area which restricted design repair options to concepts which could be implemented remotely. Several design options were considered for repairing the lead so that it can sustain the loads for 7.5 Vs conditions at full toroidal field. A clamp, along with preloaded banding straps and shim bags, provides a system that guarantees that the stress at the crack location is always compressive and prevents further crack growth in the conductor. Due to the limited space available for the repair, it was necessary to design the clamp system to operate at the material yield stress. The primary components of the clamp system were verified by load tests prior to installation. The main body of the clamp contains a load cell and potentiometer for monitoring the load-deflection characteristics of the clamp and conductors during plasma operation. Strain gages provides redundant instrumentation. If required, the preload on the conductors can be increased remotely by a special wrench attached to the clamp assembly

  8. Energy well. Ground-source heat in one-family houses; Energiakaivo. Maalaemmoen hyoedyntaeminen pientaloissa

    Energy Technology Data Exchange (ETDEWEB)

    Juvonen, J.; Lapinlampi, T.

    2013-08-15

    This guide deals with the legislation, planning, building, usage and maintenance of ground-source heat systems. The guide gives recommendations and instructions on national level on the permit practices and how to carry out the whole ground-source heat system project. The main focus of the guide is on energy wells for one-family houses. The principle is that an action permit is needed to build a ground-source heat system. On ground water areas a permit according to the water act may also be required. To avoid any problems, the placement of the system needs to be planned precisely. This guide gives a comprehension to the orderer on the issues that need to be considered before ordering, during construction, when the system is running and when giving up the use of the ground-source heat system. (orig.)

  9. Optimizing the design of large-scale ground-coupled heat pump systems using groundwater and heat transport modeling

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, H.; Itoi, R.; Fujii, J. [Kyushu University, Fukuoka (Japan). Faculty of Engineering, Department of Earth Resources Engineering; Uchida, Y. [Geological Survey of Japan, Tsukuba (Japan)

    2005-06-01

    In order to predict the long-term performance of large-scale ground-coupled heat pump (GCHP) systems, it is necessary to take into consideration well-to-well interference, especially in the presence of groundwater flow. A mass and heat transport model was developed to simulate the behavior of this type of system in the Akita Plain, northern Japan. The model was used to investigate different operational schemes and to maximize the heat extraction rate from the GCHP system. (author)

  10. A new energy analysis tool for ground source heat pump systems

    Energy Technology Data Exchange (ETDEWEB)

    Michopoulos, A.; Kyriakis, N. [Process Equipment Design Laboratory, Mechanical Engineering Department, Aristotle University of Thessaloniki, POB 487, 541 24 Thessaloniki (Greece)

    2009-09-15

    A new tool, suitable for energy analysis of vertical ground source heat pump systems, is presented. The tool is based on analytical equations describing the heat exchanged with the ground, developed in Matlab {sup registered} environment. The time step of the simulation can be freely chosen by the user (e.g. 1, 2 h etc.) and the calculation time required is very short. The heating and cooling loads of the building, at the afore mentioned time step, are needed as input, along with the thermophysical properties of the soil and of the ground heat exchanger, the operation characteristic curves of the system's heat pumps and the basic ground source heat exchanger dimensions. The results include the electricity consumption of the system and the heat absorbed from or rejected to the ground. The efficiency of the tool is verified through comparison with actual electricity consumption data collected from an existing large scale ground coupled heat pump installation over a three-year period. (author)

  11. Correlation of volatile carbonyl yields emitted by e-cigarettes with the temperature of the heating coil and the perceived sensorial quality of the generated vapours.

    Science.gov (United States)

    Geiss, Otmar; Bianchi, Ivana; Barrero-Moreno, Josefa

    2016-05-01

    E-liquids generally contain four main components: nicotine, flavours, water and carrier liquids. The carrier liquid dissolves flavours and nicotine and vaporises at a certain temperature on the atomizer of the e-cigarette. Propylene glycol and glycerol, the principal carriers used in e-liquids, undergo decomposition in contact with the atomizer heating-coil forming volatile carbonyls. Some of these, such as formaldehyde, acetaldehyde and acrolein, are of concern due to their adverse impact on human health when inhaled at sufficient concentrations. The aim of this study was to correlate the yield of volatile carbonyls emitted by e-cigarettes with the temperature of the heating coil. For this purpose, a popular commercial e-liquid was machine-vaped on a third generation e-cigarette which allowed the variation of the output wattage (5-25W) and therefore the heat generated on the atomizer heating-coil. The temperature of the heating-coil was determined by infrared thermography and the vapour generated at each temperature underwent subjective sensorial quality evaluation by an experienced vaper. A steep increase in the generated carbonyls was observed when applying a battery-output of at least 15W corresponding to 200-250°C on the heating coil. However, when considering concentrations in each inhaled puff, the short-term indoor air guideline value for formaldehyde was already exceeded at the lowest wattage of 5W, which is the wattage applied in most 2nd generation e-cigarettes. Concentrations of acetaldehyde in each puff were several times below the short-term irritation threshold value for humans. Acrolein was only detected from 20W upwards. The negative sensorial quality evaluation by the volunteering vaper of the vapour generated at 20W demonstrated the unlikelihood that such a wattage would be realistically set by a vaper. This study highlights the importance to develop standardised testing methods for the assessment of carbonyl-emissions and emissions of other

  12. Federal Technology Alert: Ground-Source Heat Pumps Applied to Federal Facilities-Second Edition; FINAL

    International Nuclear Information System (INIS)

    Hadley, Donald L

    2001-01-01

    This Federal Technology Alert, which was sponsored by the U.S. Department of Energy's Office of Federal Energy Management Programs, provides the detailed information and procedures that a Federal energy manager needs to evaluate most ground-source heat pump applications. This report updates an earlier report on ground-source heat pumps that was published in September 1995. In the current report, general benefits of this technology to the Federal sector are described, as are ground-source heat pump operation, system types, design variations, energy savings, and other benefits. In addition, information on current manufacturers, technology users, and references for further reading are provided

  13. IMPACT OF GEOTHERMAL GRADIENT ON GROUND SOURCE HEAT PUMP SYSTEM MODELING

    Directory of Open Access Journals (Sweden)

    Tomislav Kurevija

    2014-07-01

    Full Text Available ndisturbed ground temperature is one of the most crucial thermogeological parameters needed for shallow geothermal resources assessment. Energy considered to be geothermal is energy stored in the ground at depths where solar radiation has no effect. At depth where undisturbed ground temperature occurs there is no influence of seasonal variations in air temperature from surface. Exact temperature value, and depth where it occurs, is functionally dependent on surface climate parameters and thermogeologic properties of ground. After abovementioned depth, increase of ground temperature is solely dependent on geothermal gradient. Accurately determined value of undisturbed ground temperature is beneficial for proper sizing of borehole heat exchangers. On practical example of building which is being heated and cooled with shallow geothermal resource, influences of undisturbed ground temperature and geothermal gradient, on size of borehole heat exchanger are going to be presented. Sizing of borehole heat exchanger was calculated with commercial software Ground Loop Designer (GLD, which uses modified line source and cylinder source solutions of heat conduction in solids.

  14. An experimental investigation on ground heat flow balance issue for a GCHP

    OpenAIRE

    Jiufa Chen; Hongqi Zheng; Qin Xue; Erming An; Weilai Qiao

    2010-01-01

    For a ground-coupled heat pump (GCHP), it is vital to keep the ground heat flow balanced in order to achieve sustainable energy-saving operation. However, the importance of this issue has not been well studied. Focused on the heat flow balance issue, this paper made an exclusive experimental study using a newly installed GCHP system with the designed cooling capacity 1960 kW and heating capacity 1590 kW. The GCHP system was equipped with a data acquisition system and had temperature sensors i...

  15. Modelling floor heating systems using a validated two-dimensional ground coupled numerical model

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Kragh, Jesper; Roots, Peter

    2005-01-01

    This paper presents a two-dimensional simulation model of the heat losses and tempera-tures in a slab on grade floor with floor heating which is able to dynamically model the floor heating system. The aim of this work is to be able to model, in detail, the influence from the floor construction...... the floor. This model can be used to design energy efficient houses with floor heating focusing on the heat loss through the floor construction and foundation. It is found that it is impor-tant to model the dynamics of the floor heating system to find the correct heat loss to the ground, and further......, that the foundation has a large impact on the energy consumption of buildings heated by floor heating. Consequently, this detail should be in focus when designing houses with floor heating....

  16. Post-evaluation of a ground source heat pump system for residential space heating in Shanghai China

    Science.gov (United States)

    Lei, Y.; Tan, H. W.; Wang, L. Z.

    2017-11-01

    Residents of Southern China are increasingly concerned about the space heating in winter. The chief aim of the present work is to find a cost-effective way for residential space heating in Shanghai, one of the biggest city in south China. Economic and energy efficiency of three residential space heating ways, including ground source heat pump (GSHP), air source heat pump (ASHP) and wall-hung gas boiler (WHGB), are assessed based on Long-term measured data. The results show that the heat consumption of the building is 120 kWh/m2/y during the heating season, and the seasonal energy efficiency ratio (SEER) of the GSHP, ASHP and WHGB systems are 3.27, 2.30, 0.88 respectively. Compared to ASHP and WHGB, energy savings of GSHP during the heating season are 6.2 kgce/(m2.y) and 2.2 kgce/(m2.y), and the payback period of GSHP are 13.3 and 7.6 years respectively. The sensitivity analysis of various factors that affect the payback period is carried out, and the results suggest that SEER is the most critical factor affecting the feasibility of ground source heat pump application, followed by building load factor and energy price factor. These findings of the research have led the author to the conclusion that ground source heat pump for residential space heating in Shanghai is a good alternative, which can achieve significant energy saving benefits, and a good system design and operation management are key factors that can shorten the payback period.

  17. Ground source geothermal heat. Ground source heat pumps and underground thermal energy storage systems. Proceedings; Oberflaechennahe Geothermie. Erdgekoppelte Waermepumpen und unterirdische thermische Energiespeicher. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    At the ninth international user forum on shallow geothermal heat on 28th and 29th April, 2009, at BadStaffelstein (Federal Republic of Germany), the following lectures were held: (1) Information system on shallow geothermal heat for Bavaria (Marcellus Schulze); (2) Calculation of the spreading of temperature anomalies in groundwater as an instrument of planning of heat pump systems (Wolfgang Rauch); (3) Comparison of models for simulation of deep geothermal probes (Markus Proell); (4) Impact of the geometry of boreholes and probes on heat transport (Manfred Reuss); (5) Thermal respond tests and temperature depth profiles - Experience from research and practice (Markus Kuebert); (6) A model of simulation for the investigation of the impact of different heat transfer fluids on the efficiency of ground source heat pump devices (Roland Koenigsdorff); (7) The research project EWSplus - Investigations for quality assurance of geothermal probes (Mathieu Riegger); (8) Quality management of plants for the utilization of shallow geothermal heat with geothermal probes - the example of Baden-Wuerttemberg (Bruno Lorinser, Ingrid Stober); (9) Not every heat pump contributes to climate protection (Falk Auer); (10) Field measurements of heat pumps in residential buildings with modern standard and in older buildings (Marek Miara); (11) System technology for a great annual performance factor (Werner Schenk); (12) Modification of older geothermal heat probe devices for use with modern heat pumps (Klaus Friedrich Staerk); (13) Energy-efficient modernisation of a pensioners' condominium from the 1970s with solar-geothermal-air (Michael Guigas); (14) Evaluation and optimization of operation of seasonal storage systems in the foundations of office buildings (Herdis Kipry); (15) Evaluation of an innovative heating and cooling concept with rain water vessels, thermo-active building components and phase change materials in a residential building (Doreen Kalz); (16) Contracts for ground

  18. Simulation and optimisation of a ground source heat pump with different ground heat exchanger configurations for a single-family residential house

    DEFF Research Database (Denmark)

    Pavlov, Georgi Krasimiroy; Olesen, Bjarne W.

    2012-01-01

    In the future there will be an increased demand for energy efficient cooling of residential buildings. Therefore it is essential to develop cooling concepts that are passive and/or using very little primary energy. A possible solution is a ground source heat pump combined with a low-temperature h....... For the studied geographical location, passive cooling by bypassing the heat pump and using only the ground heat exchanger can provide acceptable room temperatures.......In the future there will be an increased demand for energy efficient cooling of residential buildings. Therefore it is essential to develop cooling concepts that are passive and/or using very little primary energy. A possible solution is a ground source heat pump combined with a low......-temperature heating and high-temperature cooling system. The present work evaluates the performance in relation to thermal comfort and energy consumption of a GSHP with different GHE concepts. The different configurations are analyzed being part of the energy supply system of a low-energy residential house...

  19. Annual investigation of vertical type ground source heat pump system performance on a wall heating and cooling system in Istanbul

    Energy Technology Data Exchange (ETDEWEB)

    Akbulut, U.; Yoru, Y.; Kincay, O. [Department of Mechanical Engineering, Yildiz Technical University (Turkey)], email: akbulutugur@yahoo.com, email: yilmazyoru@gmail.com, email: okincay@yildiz.edu.tr

    2011-07-01

    Wall heating and cooling systems (WHCS) are equipped with heating serpentines or panels for water circulation. These systems operate in a low temperature range so they are preferable to other, conventional systems. Furthermore, when these systems are connected to a ground source heat pump (GSHP) system, energy performance and thermal comfort are further enhanced. The purpose of this paper is to report the results of an annual inspection done on a vertical type ground-coupled heat pump systems (V-GSHP) WHCS in Istanbul and present the results. The performance data from the Yildiz Renewable Energy House at Davutpasa Campus of Yildiz Technical University, Istanbul, Turkey, during the year 2010 were collected and analyzed. The conclusions drawn from the inspection and analysis were listed in this paper. Using renewable energy sources effectively will bring both economic and environmental benefits and it is hoped that the use of these energy efficient WHCS systems will become widespread.

  20. An Innovative Use of Renewable Ground Heat for Insulation in Low Exergy Building Systems

    Directory of Open Access Journals (Sweden)

    Hansjürg Leibundgut

    2012-08-01

    Full Text Available Ground heat is a renewable resource that is readily available for buildings in cool climates, but its relatively low temperature requires the use of a heat pump to extract it for heating. We developed a system that uses low temperature ground heat directly in a building wall to reduce transmission heat losses. The Active Low Exergy Geothermal Insulation Systems (ALEGIS minimizes exergy demand and maximizes the use of renewable geothermal heat from the ground. A fluid is pumped into a small pipe network in an external layer of a wall construction that is linked to a ground heat source. This decouples the building from the outside temperature, therefore eliminating large peak demands and reducing the primary energy demand. Our steady-state analysis shows that at a design temperature of −10 °C the 6 cm thick active insulation system has equivalent performance to 11 cm of passive insulation. Our comparison of heating performance of a building with our active insulation system versus a building with static insulation of the same thickness shows a 15% reduction in annual electricity demand, and thus exergy input. We present an overview of the operation and analysis of our low exergy concept and its modeled performance.

  1. Non-equilibrium effects evidenced by vibrational spectra during the coil-to-globule transition in poly(N-isopropylacrylamide) subjected to an ultrafast heating-cooling cycle.

    Science.gov (United States)

    Deshmukh, Sanket A; Kamath, Ganesh; Suthar, Kamlesh J; Mancini, Derrick C; Sankaranarayanan, Subramanian K R S

    2014-03-14

    Molecular dynamics simulations in conjunction with finite element calculations are used to explore the conformational dynamics of a thermo-sensitive oligomer, namely poly(N-isopropylacrylamide) (PNIPAM), subjected to an ultra-fast heating-cooling cycle. Finite element (FE) calculations were used to predict the temperature profile resulting from laser-induced heating of the polymer-aqueous system. The heating rate (∼0.6 K ps(-1)) deduced from FE calculations was used to heat an aqueous solution of PNIPAM consisting of 30 monomeric units (30-mer) from 285 K to 315 K. Non-equilibrium effects arising from the ultra-fast heating-cooling cycle results in a hysteresis during the coil-to-globule transition. The corresponding atomic scale conformations were characterized by monitoring the changes in the vibrational spectra, which provided a reliable metric to study the coil-to-globule transition in PNIPAM and vice-versa across the LCST. The vibrational spectra of bonds involving atoms from the oligomer backbone and the various side-groups (amide I, amide II, and the isopropyl group of PNIPAM) of the oligomers were analyzed to study the conformational changes in the oligomer corresponding to the observed hysteresis. The differences in the vibrational spectra calculated at various temperatures during heating and cooling cycles were used to understand the coil-to-globule and globule-to-coil transitions in the PNIPAM oligomer and identify the changes in the relative interactions between various atoms in the backbone and in the side groups of the oligomer with water. The shifts in the computed vibrational spectral peaks and the changes in the intensity of peaks for the different regions of PNIPAM, seen across the LCST during the heating cycle, are in good agreement with previous experimental studies. The changes in the radius of gyration (Rg) and vibrational spectra for amide I and amide II regions of PNIPAM suggest a clear coil-to-globule transition at ∼301 K during the

  2. Simulation of a combined heating, cooling and domestic hot water system based on ground source absorption heat pump

    International Nuclear Information System (INIS)

    Wu, Wei; You, Tian; Wang, Baolong; Shi, Wenxing; Li, Xianting

    2014-01-01

    Highlights: • A combined heating/cooling/DHW system based on GSAHP is proposed in cold regions. • The soil imbalance is effectively reduced and soil temperature can be kept stable. • 20% and 15% of condensation/absorption heat is recovered by GSAHP to produce DHW. • The combined system can improve the primary energy efficiency by 23.6% and 44.4%. - Abstract: The amount of energy used for heating and domestic hot water (DHW) is very high and will keep increasing. The conventional ground source electrical heat pump used in heating-dominated buildings has the problems of thermal imbalance, decrease of soil temperature, and deterioration of heating performance. Ground source absorption heat pump (GSAHP) is advantageous in both imbalance reduction and primary energy efficiency (PEE) improvement; however, the imbalance is still unacceptable in the warmer parts of cold regions. A combined heating/cooling/DHW (HCD) system based on GSAHP is proposed to overcome this problem. The GSAHPs using generator absorber heat exchange (GAX) and single-effect (SE) cycles are simulated to obtain the performance under various working conditions. Different HCD systems in Beijing and Shenyang are simulated comparatively in TRNSYS, based on which the thermal imbalance, soil temperature, heat recovery, and energy efficiency are analyzed. Results show that GSAHP–GAX–HCD is suitable for Beijing and GSAHP–SE–HCD is suitable for Shenyang. The imbalance ratio can be reduced to −14.8% in Beijing and to 6.0% in Shenyang with an annual soil temperature variation of only 0.5 °C and 0.1 °C. Furthermore, about 20% and 15% of the total condensation/absorption heat is recovered to produce DHW, and the PEE can reach 1.516 in Beijing and 1.163 in Shenyang. The combined HCD systems can achieve a PEE improvement of 23.6% and 44.4% compared with the normal heating/cooling systems

  3. Experimental Assessment of a Helical Coil Heat Exchanger Operating at Subcritical and Supercritical Conditions in a Small-Scale Solar Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2017-05-01

    Full Text Available In this study, the performance of a helical coil heat exchanger operating at subcritical and supercritical conditions is analysed. The counter-current heat exchanger was specially designed to operate at a maximal pressure and temperature of 42 bar and 200 °C, respectively. The small-scale solar organic Rankine cycle (ORC installation has a net power output of 3 kWe. The first tests were done in a laboratory where an electrical heater was used instead of the concentrated photovoltaic/thermal (CPV/T collectors. The inlet heating fluid temperature of the water was 95 °C. The effects of different parameters on the heat transfer rate in the heat exchanger were investigated. Particularly, the performance analysis was elaborated considering the changes of the mass flow rate of the working fluid (R-404A in the range of 0.20–0.33 kg/s and the inlet pressure varying from 18 bar up to 41 bar. Hence, the variation of the heat flux was in the range of 5–9 kW/m2. The results show that the working fluid’s mass flow rate has significant influence on the heat transfer rate rather than the operational pressure. Furthermore, from the comparison between the experimental results with the heat transfer correlations from the literature, the experimental results fall within the uncertainty range for the supercritical analysis but there is a deviation of the investigated subcritical correlations.

  4. Research of the Effectiveness of Using Air and Ground Low-grade Heat for Buildings Heating in Different Regions of Russia

    Directory of Open Access Journals (Sweden)

    Vasilyev G.P.

    2016-01-01

    Full Text Available The article presents the results of research on zoning of the Russian Federation based on efficiency of utilization of the low-grade heat of ground and air as well as combinations thereof for heating buildings. When modeling thermal behavior of geothermal HHS in the climatic conditions of various regions of the Russian Federation we considered the effect of long-term recovery of geothermal heat on the thermal behavior of the ground, as well as the effect of the ground pore water phase transitions on the operational efficiency of geothermal heat pump heating systems. The zoning took into account temperature drop of the ground mass caused by many years of heat recovery from the ground. Ground temperatures expected for the 5th year of geothermal HHS operation were used as design ground mass temperatures.

  5. Mathematical modelling of thermal and flow processes in vertical ground heat exchangers

    Directory of Open Access Journals (Sweden)

    Pater Sebastian

    2017-12-01

    Full Text Available The main task of mathematical modelling of thermal and flow processes in vertical ground heat exchanger (BHE-Borehole Heat Exchanger is to determine the unit of borehole depth heat flux obtainable or transferred during the operation of the installation. This assignment is indirectly associated with finding the circulating fluid temperature flowing out from the U-tube at a given inlet temperature of fluid in respect to other operational parameters of the installation.

  6. Numerical and experimental analysis of a horizontal ground-coupled heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, University of Firat, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, University of Firat, 23119 Elazig (Turkey)

    2007-03-15

    The main objective of this work is to evaluate a heat pump system using the ground as a source of heat. A ground-coupled heat pump (GCHP) system has been installed and tested at the test room, University of Firat, Elazig, Turkey. Results obtained during experimental testing are presented and discussed here. The coefficient of performance (COP{sub sys}) of the GCHP system is determined from the measured data. A numerical model of heat transfer in the ground was developed for determining the temperature distribution in the vicinity of the pipe. The finite difference approximation is used for numerical analysis. It is observed that the numerical results agree with the experimental results. (author) (author)

  7. Experimental Study and Modeling of Ground-Source Heat Pumps with Combi-Storage in Buildings

    Directory of Open Access Journals (Sweden)

    Wessam El-Baz

    2018-05-01

    Full Text Available There is a continuous growth of heat pump installations in residential buildings in Germany. The heat pumps are not only used for space heating and domestic hot water consumption but also to offer flexibility to the grid. The high coefficient of performance and the low cost of heat storages made the heat pumps one of the optimal candidates for the power to heat applications. Thus, several questions are raised about the optimal integration and control of heat pump system with buffer storages to maximize its operation efficiency and minimize the operation costs. In this paper, an experimental investigation is performed to study the performance of a ground source heat pump (GSHP with a combi-storage under several configurations and control factors. The experiments were performed on an innovative modular testbed that is capable of emulating a ground source to provide the heat pump with different temperature levels at different times of the day. Moreover, it can emulate the different building loads such as the space heating load and the domestic hot water consumption in real-time. The data gathered from the testbed and different experimental studies were used to develop a simulation model based on Modelica that can accurately simulate the dynamics of a GSHP in a building. The model was validated based on different metrics. Energetically, the difference between the developed model and the measured values was only 3% and 4% for the heat generation and electricity consumption, respectively.

  8. A study of Ground Source Heat Pump based on a heat infiltrates coupling model established with FEFLOW

    Science.gov (United States)

    Chen, H.; Hu, C.; Chen, G.; Zhang, Q.

    2017-12-01

    Geothermal heat is a viable source of energy and its environmental impact in terms of CO2 emissions is significantly lower than conventional fossil fuels. it is vital that engineers acquire a proper understanding about the Ground Source Heat Pump (GSHP). In this study, the model of the borehole exchanger under conduction manners and heat infiltrates coupling manners was established with FEFLOW. The energy efficiency, heat transfer endurance and heat transfer in the unit depth were introduced to quantify the energy efficient and the endurance period. The performance of a the Borehole Exchanger (BHE) in soil with and without groundwater seepage was analyzed of heat transfer process between the soil and the working fluid. Basing on the model, the varied regularity of energy efficiency performance an heat transfer endurance with the conditions including the different configuration of the BHE, the soil properties, thermal load characteristic were discussed. Focus on the heat transfer process in multi-layer soil which one layer exist groundwater flow. And an investigation about thermal dispersivity was also analyzed its influence on heat transfer performance. The final result proves that the model of heat infiltrates coupling model established in this context is reasonable, which can be applied to engineering design.

  9. Thermal-economic modeling and optimization of vertical ground-coupled heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Niroomand, Behzad [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16488 (Iran)

    2009-04-15

    The optimal design process of a ground source heat pump includes thermal modeling of the system and selection of optimal design parameters which affect the system performance as well as initial and operational costs. In this paper, the modeling and optimizing processes of a ground-coupled heat pump (GCHP) with closed vertical ground heat exchanger (VGHX) are presented. To verify the modeling procedure of heat pump and VGHX systems, the simulation outputs were compared with the corresponding values reported in the literature and acceptable accuracy was obtained. Then an objective function (the sum of annual operating and investment costs of the system) was defined and minimized, exposed to the specified constraints to estimate the optimum design parameters (decision variables). Two Nelder-Mead and genetic algorithm optimization techniques were applied to guarantee the validity of the optimization results. For the given heating/cooling loads and various climatic conditions, the optimum values of heat pump design parameters (saturated temperature/pressure of condenser and evaporator) as well as VGHX design parameters (inlet and outlet temperatures of the ground water source, pipe diameter, depth and number of boreholes) were predicted. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, soil type, and number of boreholes were discussed. Finally, the sensitivity analysis of change in optimum design parameters with increase in the investment and electricity costs was performed. (author)

  10. Thermal-economic modeling and optimization of vertical ground-coupled heat pump

    International Nuclear Information System (INIS)

    Sanaye, Sepehr; Niroomand, Behzad

    2009-01-01

    The optimal design process of a ground source heat pump includes thermal modeling of the system and selection of optimal design parameters which affect the system performance as well as initial and operational costs. In this paper, the modeling and optimizing processes of a ground-coupled heat pump (GCHP) with closed vertical ground heat exchanger (VGHX) are presented. To verify the modeling procedure of heat pump and VGHX systems, the simulation outputs were compared with the corresponding values reported in the literature and acceptable accuracy was obtained. Then an objective function (the sum of annual operating and investment costs of the system) was defined and minimized, exposed to the specified constraints to estimate the optimum design parameters (decision variables). Two Nelder-Mead and genetic algorithm optimization techniques were applied to guarantee the validity of the optimization results. For the given heating/cooling loads and various climatic conditions, the optimum values of heat pump design parameters (saturated temperature/pressure of condenser and evaporator) as well as VGHX design parameters (inlet and outlet temperatures of the ground water source, pipe diameter, depth and number of boreholes) were predicted. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, soil type, and number of boreholes were discussed. Finally, the sensitivity analysis of change in optimum design parameters with increase in the investment and electricity costs was performed

  11. National Certification Standard for Ground Source Heat Pump Personnel

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, John [Geothermal Heat Pump Consortium, Washington, DC (United States)

    2013-07-31

    The National Certification Standard for the Geothermal Heat Pump Industry adds to the understanding of the barriers to rapid growth of the geothermal heat pump (GHP) industry by bringing together for the first time an analysis of the roles and responsibilities of each of the individual job tasks involved in the design and installation of GHP systems. The standard addresses applicable qualifications for all primary personnel involved in the design, installation, commissioning, operation and maintenance of GHP systems, including their knowledge, skills and abilities. The resulting standard serves as a foundation for subsequent development of curriculum, training and certification programs, which are not included in the scope of this project, but are briefly addressed in the standard to describe ways in which the standard developed in this project may form a foundation to support further progress in accomplishing those other efforts. Follow-on efforts may use the standard developed in this project to improve the technical effectiveness and economic feasibility of curriculum development and training programs for GHP industry personnel, by providing a more complete and objective assessment of the individual job tasks necessary for successful implementation of GHP systems. When incorporated into future certification programs for GHP personnel, the standard will facilitate increased consumer confidence in GHP technology, reduce the potential for improperly installed GHP systems, and assure GHP system quality and performance, all of which benefit the public through improved energy efficiency and mitigated environmental impacts of the heating and cooling of homes and businesses.

  12. Ground-water temperature of the Wyoming quadrangle in central Delaware : with application to ground-water-source heat pumps

    Science.gov (United States)

    Hodges, Arthur L.

    1982-01-01

    Ground-water temperature was measured during a one-year period (1980-81) in 20 wells in the Wyoming Quadrangle in central Delaware. Data from thermistors set at fixed depths in two wells were collected twice each week, and vertical temperature profiles of the remaining 18 wells were made monthly. Ground-water temperature at 8 feet below land surface in well Jc55-1 ranged from 45.0 degrees F in February to 70.1 degrees F in September. Temperature at 35 feet below land surface in the same well reached a minimum of 56.0 degrees F in August, and a maximum of 57.8 degrees F in February. Average annual temperature of ground water at 25 feet below land surface in all wells ranged from 54.6 degrees F to 57.8 degrees F. Variations of average temperature probably reflect the presence or absence of forestation in the recharge areas of the wells. Ground-water-source heat pumps supplied with water from wells 30 or more feet below land surface will operate more efficiently in both heating and cooling modes than those supplied with water from shallower depths. (USGS)

  13. Self-sensing of deflection, force, and temperature for joule-heated twisted and coiled polymer muscles via electrical impedance

    NARCIS (Netherlands)

    van der Weijde, J.O.; Smit (student), B.; Fritschi, M.; van de Kamp, C.; Vallery, H.

    2017-01-01

    The recently introduced twisted and coiled polymer muscle is an inexpensive and lightweight compliant actuator. Incorporation of themuscle in applications that rely on feedback creates the need for deflection and force sensing. In this paper, we explore a sensing principle that does not require

  14. Horizontal ground coupled heat pump: Thermal-economic modeling and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Niroomand, Behzad [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST) (Iran)

    2010-12-15

    The modeling and optimizing processes of a Ground Coupled Heat Pump (GCHP) with closed Horizontal Ground Heat eXchanger (HGHX) are presented in this paper. After thermal modeling of GCHP including HGHX, the optimum design parameters of the system were estimated by minimizing a defined objective function (total of investment and operation costs) subject to a list of constraints. This procedure was performed applying Genetic Algorithm technique. For given heating/cooling loads and various climatic conditions, the optimum values of saturated temperature/pressure of condenser and evaporator as well as inlet and outlet temperatures of the water source in cooling and heating modes were predicted. Then, for our case study, the design parameters as well as the configuration of HGHX were obtained. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, and soil type were discussed. (author)

  15. Horizontal ground coupled heat pump: Thermal-economic modeling and optimization

    International Nuclear Information System (INIS)

    Sanaye, Sepehr; Niroomand, Behzad

    2010-01-01

    The modeling and optimizing processes of a Ground Coupled Heat Pump (GCHP) with closed Horizontal Ground Heat eXchanger (HGHX) are presented in this paper. After thermal modeling of GCHP including HGHX, the optimum design parameters of the system were estimated by minimizing a defined objective function (total of investment and operation costs) subject to a list of constraints. This procedure was performed applying Genetic Algorithm technique. For given heating/cooling loads and various climatic conditions, the optimum values of saturated temperature/pressure of condenser and evaporator as well as inlet and outlet temperatures of the water source in cooling and heating modes were predicted. Then, for our case study, the design parameters as well as the configuration of HGHX were obtained. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, and soil type were discussed.

  16. Cooling performance of a vertical ground-coupled heat pump system installed in a school building

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yujin; Lee, Jae-Keun; Jeong, Young-Man; Koo, Kyung-Min [Department of Mechanical Engineering, Pusan National University, San 30, Jangjeon-Dong, Kumjung-Ku, Busan 609-735 (Korea); Lee, Dong-Hyuk; Kim, In-Kyu; Jin, Sim-Won [LG Electronics, 391-2 Gaeumjeong-dong, Changwon City, Gyeongnam (Korea); Kim, Soo H. [Department of Nanosystems and Nanoprocess Engineering, Pusan National University, San 30, Jangjeon-Dong, Kumjung-Ku, Busan 609-735 (Korea)

    2009-03-15

    This paper presents the cooling performance of a water-to-refrigerant type ground heat source heat pump system (GSHP) installed in a school building in Korea. The evaluation of the cooling performance has been conducted under the actual operation of GSHP system in the summer of year 2007. Ten heat pump units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. To analyze the cooling performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the cooling capacity and the input power were evaluated to determine the cooling performance of the GSHP system. The average cooling coefficient of performance (COP) and overall COP of the GSHP system were found to be {proportional_to}8.3 and {proportional_to}5.9 at 65% partial load condition, respectively. While the air source heat pump (ASHP) system, which has the same capacity with the GSHP system, was found to have the average COP of {proportional_to}3.9 and overall COP of {proportional_to}3.4, implying that the GSHP system is more efficient than the ASHP system due to its lower temperature of condenser. (author)

  17. First in situ operation performance test of ground source heat pump in Tunisia

    International Nuclear Information System (INIS)

    Naili, Nabiha; Attar, Issam; Hazami, Majdi; Farhat, Abdelhamid

    2013-01-01

    Highlights: • Evaluate the geothermal energy in Tunisia. • Study of the performance of GSHP system for cooling space. • GSHP is a promising alternative for building cooling in Tunisia. - Abstract: The main purpose of this paper is to study the energetic potential of the deployment in Tunisia of the Ground Source Heat Pump (GSHP) system for cooling mode application. Therefore, a pilot GSHP system using horizontal Ground Heat Exchanger (GHE) was installed and experimented in the Research and Technology Center of Energy (CRTEn), Borj Cédria. The experiment is conducted in a test room with a floor area of about 12 m 2 . In the floor of the tested room is integrated a polyethylene exchanger (PEX) used as a radiant floor cooling (RFC) system. The experimental setup mainly includes the ground temperature, the temperature and flow rate of water circulating in the heat pump and the GHE, as well as the power consumption of the heat pump and circulating pumps. These experimental data are essentially used to evaluate the coefficient of performance of the heat pump (COP hp ) and the overall system (COP sys ) for continuous operation mode. The COP hp and the COP sys were found to be 4.25 and 2.88, respectively. These results reveal that the use of the ground source heat pump is very appropriate for Tunisian building cooling

  18. Fabrication of the new poloidal field coils for DIII-D

    International Nuclear Information System (INIS)

    Heiberger, M.; Bott, R.J.; Gallix, R.; Street, R.W.

    1986-01-01

    The six new poloidal field coil assemblies manufactured by GA Technologies (GA) for DIII-D range in diameter from 3.4-5.3 m. Two of them are 55-turn field shaping coils. Each of the other four combines one turn of the ohmic heating coil and a 55-turn field shaping coil into a single unit encased in a stainless steel box beam. These four box beams, which provide support for the coils inside, are part of the overall coil and vacuum vessel support structure. They also serve as molds for vacuum impregnating the coils with epoxy. All coils are made of hollow, water-cooled copper conductor. The larger field shaping coils are designed for 20 kA, 3 sec rectangular current pulses with 40 0 C temperature rise. The ohmic heating coil turns are capable of currents of up to 110 kA. The conductor is wrapped with Kapton and fiberglass tape; Kapton provides 1000 V/turn and 28 kV coil-to-ground insulation. The fiberglass acts as wick and reinforcement for the vacuum impregnated epoxy resin which bonds the coil together. The fabrication process is described in detail and illustrated. Tools and setups used for special operations such as induction brazing, conductor winding, conductor bending, and vacuum impregnation are presented. The quality control procedures followed to guarantee sound brazed joints are explained. The electrical tests performed at several stages of fabrication, especially the 1000 V/turn impulse tests conducted before potting to facilitate fault detection and repair, are described

  19. Estimation of performance of a J-T refrigerators operating with nitrogen-hydrocarbon mixtures and a coiled tubes-in-tube heat exchanger

    Science.gov (United States)

    Satya Meher, R.; Venkatarathnam, G.

    2018-06-01

    The exergy efficiency of Joule-Thomson (J-T) refrigerators operating with mixtures (MRC systems) strongly depends on the choice of refrigerant mixture and the performance of the heat exchanger used. Helically coiled, multiple tubes-in-tube heat exchangers with an effectiveness of over 96% are widely used in these types of systems. All the current studies focus only on the different heat transfer correlations and the uncertainty in predicting performance of the heat exchanger alone. The main focus of this work is to estimate the uncertainty in cooling capacity when the homogenous model is used by comparing the theoretical and experimental studies. The comparisons have been extended to some two-phase models present in the literature as well. Experiments have been carried out on a J-T refrigerator at a fixed heat load of 10 W with different nitrogen-hydrocarbon mixtures in the evaporator temperature range of 100-120 K. Different heat transfer models have been used to predict the temperature profiles as well as the cooling capacity of the refrigerator. The results show that the homogenous two-phase flow model is probably the most suitable model for rating the cooling capacity of a J-T refrigerator operating with nitrogen-hydrocarbon mixtures.

  20. Analysis of Fuel Cell Driven Ground Source Heat Pump Systems in Community Buildings

    Directory of Open Access Journals (Sweden)

    Jong-Keun Shin

    2013-05-01

    Full Text Available In the present study, a fuel cell driven ground source heat pump (GSHP system is applied in a community building and heat pump system performance is analyzed by computational methods. Conduction heat transfer between the brine pipe and ground is analyzed by TEACH code in order to predict the performance of the heat pump system. The predicted coefficient of performance (COP of the heat pump system and the energy cost were compared with the variation of the location of the objective building, the water saturation rate of the soil, and the driven powers of the heat pump system. Compared to the late-night electricity driven system, a significant reduction of energy cost can be accomplished by employing the fuel cell driven heat pump system. This is due to the low cost of electricity production of the fuel cell system and to the application of the recovered waste heat generated during the electricity production process to the heating of the community building.

  1. Operation performance investigation of ground-coupled heat-pump system for temperate region

    OpenAIRE

    Yi Man; Hongxing Yang; Jinggang Wang; Zhaohong Fang

    2010-01-01

    In order to investigate the operation performance of ground-coupled heat-pump (GCHP) system, an analytical simulation model of GCHP system on short time-step basis and a computer program based on this model to predict system operating parameters are developed in this study. Besides, detailed on-site experiments on GCHP test rig installed in a temperate region of China are carried out. The temperature distributions of borehole as well as ground around borehole at different depths are evaluated...

  2. Optimization of Serial Combined System of Ground-Coupled Heat Pump and Solar Collector

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; CHEN Yan; LU Suzhen; CUI Junkui

    2009-01-01

    A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results,in which the solar collector was combined serially with a ground-coupled heat pump(GCHP).The universal optimal equations were solved by the constrained variable metric method considering both the performance and economics.Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating.The results indicated a system coefficient of performance(COP)of 3.9 for the optimal method under the seriaI heating mode,and 3.2 for the conventional one.In addition,the optimum solution also showed advantages in energy and cost saving.1eading to a 16.7%improvement in the heat pump performance at 17.2%less energy consumption and 11.8%lower annual cost,respectively.

  3. Recovery Act: Finite Volume Based Computer Program for Ground Source Heat Pump Systems

    Energy Technology Data Exchange (ETDEWEB)

    James A Menart, Professor

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled Finite Volume Based Computer Program for Ground Source Heat Pump Systems. The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump. The

  4. Finite Volume Based Computer Program for Ground Source Heat Pump System

    Energy Technology Data Exchange (ETDEWEB)

    Menart, James A. [Wright State University

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled ?Finite Volume Based Computer Program for Ground Source Heat Pump Systems.? The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump

  5. Flow and Pollutant Transport in Urban Street Canyons of Different Aspect Ratios with Ground Heating: Large-Eddy Simulation

    OpenAIRE

    Li, Xian-Xiang; Koh, Tieh-Yong; Britter, Rex E; Norford, Leslie Keith; Entekhabi, Dara

    2010-01-01

    A validated large-eddy simulation model was employed to study the effect of the aspect ratio and ground heating on the flow and pollutant dispersion in urban street canyons. Three ground-heating intensities (neutral, weak and strong) were imposed in street canyons of aspect ratio 1, 2, and 0.5. The detailed patterns of flow, turbulence, temperature and pollutant transport were analyzed and compared. Significant changes of flow and scalar patterns were caused by ground heating in the street ca...

  6. Development of suitability maps for ground-coupled heat pump systems using groundwater and heat transport models

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Hikari; Itoi, Ryuichi [Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395 (Japan); Inatomi, Tadasuke [YBM Co. Ltd., Kishiyama 589-10 Kitahata, Karatsu 847-1211 (Japan); Uchida, Youhei [Geological Survey of Japan, AIST Tsukuba Central 7, Tsukuba 305-8567 (Japan)

    2007-10-15

    The thermophysical properties of subsurface materials (soils, sediments and rocks) and groundwater flow strongly affect the heat exchange rates of ground heat exchangers (GHEs). These rates can be maximized and the installation costs of the ground-coupled heat pump (GCHP) systems reduced by developing suitability maps based on local geological and hydrological information. Such maps were generated for the Chikushi Plain (western Japan) using field-survey data and a numerical modeling study. First, a field-wide groundwater model was developed for the area and the results matched against measured groundwater levels and vertical temperature profiles. Single GHE models were then constructed to simulate the heat exchange performance at different locations in the plain. Finally, suitability maps for GCHP systems were prepared using the results from the single GHE models. Variations in the heat exchange rates of over 40% revealed by the map were ascribed to differences in the GHE locations, confirming how important it is to use appropriate thermophysical data when designing GCHP systems. (author)

  7. A simulation-based analysis of variable flow pumping in ground source heat pump systems with different types of borehole heat exchangers: A case study

    International Nuclear Information System (INIS)

    Zarrella, Angelo; Emmi, Giuseppe; De Carli, Michele

    2017-01-01

    Highlights: • The work focuses on the variable flow in ground source heat pump systems. • The constant and variable speed circulation pumps in the ground loop are compared. • The constant temperature difference control across the heat pump is studied. • The variable flow affects the energy performance of the heat pump. • The constant temperature difference control offers an attractive energy saving. - Abstract: A simulation model of ground source heat pump systems has been used to investigate to what extent a variable flow of the heat-carrier fluid of the ground loop affects the energy efficiency of the entire system. The model contemporaneously considers the borehole heat exchangers, the heat pump, the building load, and the control strategies for the circulation pumps of the ground loop. A constant speed of the circulation pumps of the ground loop was compared with a variable flow controlled by means of a constant temperature difference across the heat pump on the ground side considering the load profile of an office building located in North Italy. The analysis was carried out for a single U-tube, double U-tube and coaxial pipe heat exchangers. The control strategies adopted to manage the flow rate of the heat-carrier fluid of the ground loop affect both the heat exchange rate of the borehole field and the heat pump’s long-term energy efficiency. The simulations show considerable differences in the system’s seasonal energy efficiency. The constant speed of the circulation pumps leads to the best results as far as the heat pump’s energy performance was concerned, but this advantage was lost because of the greater amount of electrical energy used by the circulation pumps; this, of course, affects the energy efficiency of the entire system. The optimal solution appears then to be a constant temperature difference in the heat-carrier fluid across the heat pump.

  8. Influence of the heat treatment on the color of ground pepper (Capsicum annuum

    Directory of Open Access Journals (Sweden)

    Vračar Ljubo O.

    2007-01-01

    Full Text Available Red pepper (Capsicum annuum L. is one of the most important vegetables in the world. The main ground pepper quality attributes are extractable color, surface color, qualitative and quantitative carotenoid content. In this work, the influence of heat treatment on ground pepper quality was investigated. Microbiological status was examined in non-sterilized and sterilized ground pepper. Color changes were assessed by measuring the extractable color (ASTA and surface color, using a photocolorimeter. The obtained results showed that at the end of experiment, non-sterilized samples had higher color values in comparison to the sterilized ones. Also, color deterioration was heightened at room temperature.

  9. Detailed Theoretical Characterization of a Transcritical CO2 Direct Expansion Ground Source Heat Pump Water Heater

    Directory of Open Access Journals (Sweden)

    Parham Eslami-Nejad

    2018-02-01

    Full Text Available A new avenue in modern heat pump technology is related to the use of natural refrigerants such as carbon dioxide (CO2. The use of CO2 in direct expansion ground source heat pumps (DX-GSHP has also gained significant interest as it offers opportunities for cost reduction of the ground loop, albeit some challenges remain in their development, design and use. To address these challenges and to characterize CO2-DX-GSHP performance for water heating applications, a detailed theoretical model and a fully-instrumented test apparatus was developed and built at CanmetENERGY Research Laboratory. The theoretical model was validated against a set of experimental results and adopted to investigate the performance of the system over a wide operating range. Validation results showed that the model predicts the experimental results within the measurement uncertainty. A detailed system performance analysis was also performed using the theoretical model to understand the system behavior and explore the actions required for performance improvement in future installations. The results of the analysis showed that improper design and control of some components, such as the gas cooler and ground heat exchanger can degrade the system performance by up to 25%, and the heat pump heating capacity by 7.5%.

  10. Application of ground-to-air heat exchanger for preheating of supply air

    Science.gov (United States)

    Sorokins, Juris; Borodinecs, Anatolijs; Zemitis, Jurgis

    2017-10-01

    This study focuses on assessing the contribution of the passive ground-coupled air heat exchanger system to decreasing the energy consumption of air conditioning and ventilation systems for office buildings in the Latvian climate conditions. The theoretical part of the thesis deals with methods of office building ventilation, supply air preheating and heat recovery as well as particularities of using ground-coupled air heat exchangers, their design parameters and their joint impact on the thermal performance. The engineering project part includes a ventilation system for an office building with an integrated ground-coupled air heat exchanger. By simulating energy consumption of the ventilation system for a duration of one year, the thesis analyzes the contribution of the heat exchanger to the overall energy consumption, which totals 9.53 MWh and 4.02 MWh a year, according to the desired parameters of the indoor climate. The possible alternative heat recovery solutions are investigated to reach by European Regional Development Fund project Nr.1.1.1.1/16/A/048 “NEARLY ZERO ENERGY SOLUTIONS FOR UNCLASSIFIED BUILDINGS”.

  11. Heat-transfer, inside of the ground heat-transfer units, from liquid, additionally cooling the oil-immersed transformer

    Directory of Open Access Journals (Sweden)

    Madyshev Ilnur

    2017-01-01

    Full Text Available A device for cooling the oil-immersed transformer by means of thermoelectric transducers has been developed. Their operating principle is based on the fact that at night at minimum ambient temperature, the cold is accumulated inside of a vessel due to formation of water ice layer on the developed surfaces of thermoelectric transducers` ribs. Melting of this layer is used in the hottest time of a day for additional cooling of transformer oil in the cooling system of the transformer. Pre-cooling of the circulating water takes place in vertical ground heat-transfer units (VGHT units, mounted into ground drilled boreholes. Certain estimate calculations of the heat-transfer process have been carried out.

  12. In situ study of the effect of ground source heat pump on shallow ground-water quality in the late Pleistocene terrace area of Tokyo, Japan

    Science.gov (United States)

    Takemura, T.; Uemura, K.; Akiba, Y.; Ota, M.

    2015-12-01

    The implementation of ground source heat pump (GSHP) systems has rapidly increased around the world, since they reduce carbon dioxide emissions and save electric energy. The GSHP system transfer heat into the geosphere zone when air conditioners are used to cool rooms or buildings. However, the effects of temperature increase on the quality of underground water has yet to be fully investigated. In order to reduce the risks of ground-water pollution by the installed GSHPs, it is important to evaluate the effect of temperature change on the ground-water quality. In this study, we installed a closed loop GSHP system on a heat exchange well along with a monitoring well drilled to measure ground-water quality and temperature. The monitoring well was drilled at 0.1cm away from the heat exchange well. We observed that changes of temperature in the heat exchange well affected the water quality, especially turbidity, in gravelly layer.

  13. Performance analysis of hybrid ground-coupled heat pump system with multi-functions

    International Nuclear Information System (INIS)

    You, Tian; Wang, Baolong; Wu, Wei; Shi, Wenxing; Li, Xianting

    2015-01-01

    Highlights: • The hybrid GCHP system with multi-functions is proposed. • The system maintains the soil temperature and heating reliability steady. • The multi-functional operation of HCUT can save more energy of the system. - Abstract: Underground thermal imbalance is a significant problem for ground-coupled heat pump (GCHP) systems that serve predominately heated buildings in cold regions, which extract more heat from the ground and inject less heat, especially in buildings requiring domestic hot water (DHW). To solve this problem, a previously developed heat compensation unit with thermosyphon (HCUT) is integrated with a GCHP unit to build a hybrid GCHP system. To improve the energy savings of this hybrid GCHP system, the HCUT unit is set to have multiple functions (heat compensation, direct DHW and direct space heating) in this paper. To analyze the improved system performance, a hotel requiring air-conditioning and DHW is selected and simulated in three typical cold cities using the dynamic software DeST and TRNSYS. The results indicate that the hybrid GCHP system can maintain the underground thermal balance while keeping the indoor air temperature within the design range. Furthermore, the HCUT unit efficiently reduces the energy consumption via its multi-functional operations. Compared to the previous system that only used HCUT for heat compensation, adding the direct DHW function further saves 7.5–11.0% energy in heat compensation (HC) and DHW (i.e., 3.6–4.8% of the whole system). Simultaneously adding the direct DHW and space heating functions to the HCUT can save 9.8–12.9% energy in HC and DHW (i.e., 5.1–6.0% of the whole system). The hybrid GCHP system with a multi-functional HCUT provides more energy savings while maintaining the underground thermal balance in cold regions that demand both air-conditioning and DHW

  14. Sensitivity analysis on the performances of a closed-loop Ground Source Heat Pump

    Science.gov (United States)

    Casasso, Alessandro; Sethi, Rajandrea

    2014-05-01

    Ground Source Heat Pumps (GSHP) permit to achieve a significant reduction of greenhouse gas emissions, and the margins for economic saving of this technology are strongly correlated to the long-term sustainability of the exploitation of the heat stored in the soil. The operation of a GSHP over its lifetime should be therefore modelled considering realistic conditions, and a thorough characterization of the physical properties of the soil is essential to avoid large errors of prediction. In this work, a BHE modelling procedure with the finite-element code FEFLOW is presented. Starting from the governing equations of the heat transport in the soil around a GSHP and inside the BHE, the most important parameters are individuated and the adopted program settings are explained. A sensitivity analysis is then carried on both the design parameters of the heat exchanger, in order to understand the margins of improvement of a careful design and installation, and the physical properties of the soil, with the aim of quantifying the uncertainty induced by their variability. The relative importance of each parameter is therefore assessed by comparing the statistical distributions of the fluid temperatures and estimating the energy consumption of the heat pump, and practical conclusions are from these results about the site characterization, the design and the installation of a BHE. References Casasso A., Sethi R., 2014 Efficiency of closed loop geothermal heat pumps: A sensitivity analysis, Renewable Energy 62 (2014), pp. 737-746 Chiasson A.C., Rees S.J., Spitler J.D., 2000, A preliminary assessment of the effects of groundwater flow on closed-loop ground-source heat pump systems, ASHRAE Transactions 106 (2000), pp. 380-393 Delaleux F., Py X., Olives R., Dominguez A., 2012, Enhancement of geothermal borehole heat exchangers performances by improvement of bentonite grouts conductivity, Applied Thermal Engineering 33-34, pp. 92-99 Diao N., Li Q., Fang Z., 2004, Heat transfer in

  15. Study of the Dependence Effectiveness of Low-potential Heat of the Ground and Atmospheric Air for Heating Buildings from Climatic parameters

    Directory of Open Access Journals (Sweden)

    Vasilyev Gregory P.

    2016-01-01

    Full Text Available The article represents the results of researches for division into districts of the territory of Russia and Europe by efficiency of using for the heat supply of buildings of low-potential thermal energy of ground and free air and their combination. While modeling of the heat regime of geothermal HPS in climatic conditions of different regions of the territory of Russia, the influence has been taken into account of the long-term extraction of geothermal heat energy on the ground heat regime as well as the influence of phase transitions of pore moisture in ground on the efficiency of operation of geothermal heat-pump heat-supply systems. While realization of the division into districts, the sinking of temperatures of ground massive was been taken into account which has been called by long-term extraction of the heat energy from the ground, and as calculation parameters of the heat energy from the ground, and as calculation parameters of ground massive temperatures, the ground temperatures were used which are waited for the 5-th year of operation of geothermal HPS.

  16. Dynamic energy converters using an outer heat source for ground uses. Bibliographic study

    International Nuclear Information System (INIS)

    Bousquet, Jean-Louis du

    1969-01-01

    This short bibliographical review presents the main dynamical conversion systems operating with an outer heat source, used for power ranges of a few hundreds Watts to a few hundreds kilowatts and dedicated to ground uses. The study has three parts: recollection of thermodynamic cycles; review of some present or projected realizations; a critical study for selecting converter components (turbine, reciprocating engine, thermodynamical fluid) [fr

  17. The influence of soil moisture transfer on building heat loss via the ground

    NARCIS (Netherlands)

    Janssen, H.M.; Carmeliet, J.; Hens, H.

    2004-01-01

    In this paper, the influence of soil moisture transfer on building heat loss via the ground is investigated by comparing fully coupled simulations with linear thermal simulations. The observed influences of coupling are (1) the larger amplitude of surface temperature, (2) the variation of thermal

  18. Vertical-borehole ground-coupled heat pumps: A review of models and systems

    Energy Technology Data Exchange (ETDEWEB)

    Yang, H.; Cui, P. [Renewable Energy Research Group, Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong (China); Fang, Z. [Ground Source Heat Pump Research Center, Shandong Jianzhu University, Jinan (China)

    2010-01-15

    A large number of ground-coupled heat pump (GCHP) systems have been used in residential and commercial buildings throughout the world due to the attractive advantages of high efficiency and environmental friendliness. This paper gives a detailed literature review of the research and developments of the vertical-borehole GCHP technology for applications in air-conditioning. A general introduction on the ground source heat pump system and its development is briefly presented first. Then, the most typical simulation models of the vertical ground heat exchangers currently available are summarized in detail including the heat transfer processes outside and inside the boreholes. The various design/simulation programs for vertical GCHP systems primarily based on the typical simulation models are also reviewed in this paper. Finally, the various hybrid GCHP systems for cooling or heating-dominated buildings are well described. It is found that the GCHP technology can be used both in cold and hot weather areas and the energy saving potential is significant. (author)

  19. A review of the cylindrical heat source method for the design and analysis of vertical ground-coupled heat pump systems

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, M. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Mecanique

    2000-12-01

    The successful design and analysis of ground-coupled heat pump (GCHP) systems depends in large part on the adequate prediction of ground water heat transfer. The author presented a detailed review of the cylindrical heat source method utilized for the prediction of transient heat transfer in vertical U-tube ground heat exchangers. The physics that underlies the theory applicable to this technology is explained in a step-by-step manner. Explanations are also provided for the equations that govern the determination of design lengths for the cylindrical heat method, as presented in the ASHRAE handbook. Some improvements were recommended by the author, such as the calculation of the effective thermal resistances using the borehole diameter instead of the equivalent U-tube diameter now in use. Annual hour-by-hour building load calculations should be used to calculate ground loads. 8 refs., 2 tabs., 5 figs., 3 appendices.

  20. Cooperation of Horizontal Ground Heat Exchanger with the Ventilation Unit During Summer - Case Study

    Science.gov (United States)

    Romańska-Zapała, Anna; Furtak, Marcin; Dechnik, Mirosław

    2017-10-01

    Renewable energy sources are used in the modern energy-efficient buildings to improve their energy balance. One of them is used in the mechanical ventilation system ground air heat exchanger (earth-air heat exchanger - EAHX). This solution, right after heat recovery from exhaust air (recuperation), allows the reduction in the energy needed to obtain the desired temperature of supply air. The article presents the results of "in situ" measurements of pipe ground air heat exchanger cooperating with the air handling unit, supporting cooling the building in the summer season, in Polish climatic conditions. The laboratory consists of a ventilation unit intake - exhaust with rotor for which the source of fresh air is the air intake wall and two air intakes field cooperating with the tube with ground air heat exchangers. Selection of the source of fresh air is performed using sprocket with actuators. This system is part of the ventilation system of the Malopolska Laboratory of Energy-Efficient Building (MLBE) building of Cracow University of Technology. The measuring system are, among others, the sensors of parameters of air inlets and outlets of the heat exchanger channels EAHX and weather station that senses the local weather conditions. The measurement data are recorded and archived by the integrated process control system in the building of MLBE. During the study measurements of operating parameters of the ventilation unit cooperating with the selected source of fresh air were performed. Two cases of operation of the system: using EAHX heat exchanger and without it, were analyzed. Potentially the use of ground air heat exchanger in the mechanical ventilation system can reduce the energy demand for heating or cooling rooms by the pre-adjustment of the supply air temperature. Considering the results can be concluded that the continuous use of these exchangers is not optimal. This relationship is appropriate not only on an annual basis for the transitional periods (spring

  1. Study on the System Design of a Solar Assisted Ground Heat Pump System Using Dynamic Simulation

    Directory of Open Access Journals (Sweden)

    Min Gyung Yu

    2016-04-01

    Full Text Available Recently, the use of hybrid systems using multiple heat sources in buildings to ensure a stable energy supply and improve the system performance has gained attention. Among them, a heat pump system using both solar and ground heat was developed and various system configurations have been introduced. However, establishing a suitable design method for the solar-assisted ground heat pump (SAGHP system including a thermal storage tank is complicated and there are few quantitative studies on the detailed system configurations. Therefore, this study developed three SAGHP system design methods considering the design factors focused on the thermal storage tank. Using dynamic energy simulation code (TRNSYS 17, individual performance analysis models were developed and long-term quantitative analysis was carried out to suggest optimum design and operation methods. As a result, it was found that SYSTEM 2 which is a hybrid system with heat storage tank for only a solar system showed the highest average heat source temperature of 14.81 °C, which is about 11 °C higher than minimum temperature in SYSTEM 3. Furthermore, the best coefficient of performance (COP values of heat pump and system were 5.23 and 4.32 in SYSYEM 2, using high and stable solar heat from a thermal storage tank. Moreover, this paper considered five different geographical and climatic locations and the SAGHP system worked efficiently in having high solar radiation and cool climate zones and the system COP was 4.51 in the case of Winnipeg (Canada where the highest heating demand is required.

  2. Hybrid friction diffusion bonding of 316L stainless steel tube-to-tube sheet joints for coil-wound heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Haneklaus, Nils; Cionea, Cristian; Reuven, Rony; Frazer, David; Hosemann, Peter; Peterson, Per F. [Dept of Nuclear Engineering, University of California, Berkeley (United States)

    2016-11-15

    Hybrid friction diffusion bonding (HFDB) is a solid-state bonding process first introduced by Helmholtz-Zentrum Geesthacht to join aluminum tube-to-tube sheet joints of Coil-wound heat exchangers (CWHE). This study describes how HFDB was successfully used to manufacture 316L test samples simulating tube-to-tube sheet joints of stainless steel CWHE for molten salt coolants as foreseen in several advanced nuclear- and thermal solar power plants. Engineering parameters of the test sample fabrication are presented and results from subsequent non-destructive vacuum decay leak testing and destructive tensile pull-out testing are discussed. The bonded areas of successfully fabricated samples as characterized by tube rupture during pull-out tensile testing, were further investigated using optical microscopy and scanning electron microscopy including electron backscatter diffraction.

  3. A model predictive framework of Ground Source Heat Pump coupled with Aquifer Thermal Energy Storage System in heating and cooling equipment of a building

    NARCIS (Netherlands)

    Rostampour Samarin, V.; Bloemendal, J.M.; Keviczky, T.

    2017-01-01

    This paper presents a complete model of a building heating and cooling equipment and a ground source heat pump (GSHP) coupled with an aquifer thermal energy storage (ATES) system. This model contains detailed
    mathematical representations of building thermal dynamics, ATES system dynamics, heat

  4. Hybrid ground-source heat pump system with active air source regeneration

    International Nuclear Information System (INIS)

    Allaerts, K.; Coomans, M.; Salenbien, R.

    2015-01-01

    Highlights: • A hybrid ground source heat pump system with two separate borefields is modelled. • The maximum underground storage temperature depends on the size of the drycooler. • Drycooler selection curves are given as function of underground storage temperature. • The size of the cold storage is reduced with 47% in the cost optimal configuration. • The cooling seasonal performance factor decreases with reduced storage capacity. - Abstract: Ground-source heat pump systems (GSHP) offer great advantages over traditional heating and cooling installations. However, their applications are limited due to the high initial costs of borehole drilling. One way to avoid these costs is by reducing the size of the borefield, e.g. by combining the system with other renewable energy sources or by using active regeneration to increase the system efficiency. In this paper a hybrid ground-source heat pump system (HGSHP) is analyzed. The borefield is split into a warm part and a cold part, which allows for seasonal thermal-energy storage. Additionally, supplementary drycoolers capture heat during summer and cold during winter. The relationship between the underground storage size and temperature and the drycooler capacity is described, using an office building in Flanders (Belgium) as reference case. Results show that with a HGSHP system a significant borefield size reduction can be achieved without compromising system performance; i.e. for the reference case a reduction of 47% was achieved in the cost-optimal configuration. It is also shown that the cooling seasonal performance factor decreases significantly with underground storage capacity. In addition, the HGSHP can be used to maintain or restore thermal balance in the geothermal source when heating and cooling loads do not match

  5. Efficiency of Passive Utilization of Ground “Cold” in Adaptive Geothermal Heat Pump Heating and Cooling Systems (AGHCS

    Directory of Open Access Journals (Sweden)

    Vasilyev G.P.

    2016-01-01

    Full Text Available This article deals with estimating a potential and efficiency of utilization of passive ground “cold” for cooling buildings in climatic conditions of Moscow (Russia. The article presents results of numerical analysis to assess the efficiency of reducing peak cooling loads of the building equipped with AGHCS, through the utilization of natural cold of wells for passive cooling and cold storage in summer at night (off-peak time with its subsequent consumption in the day time, both in passive mode, and with heat pumps. The conclusions of the article set out the basic principles of passive cooling in the design of AGHCS.

  6. Zoning of the Territory of Russia According to the Efficiency of the Use of Low-Grade Ground Heat for Heating

    Directory of Open Access Journals (Sweden)

    Vasilyev G.P.

    2015-01-01

    Full Text Available This paper reports the results of study on the effectiveness of using low-grade ground heat in heat pump systems under the climatic conditions of Russia. The study was performed using the software package “INSOLAR.GSHP.12”, which simulates the non-stationary thermal conditions of ground source heat pumps (GSHPs over several years of operation. The paper presents the results of the zoning of the territory of Russia according to the effectiveness of using low-grade ground heat in heat pump systems. The zoning was performed with consideration of the decrease of the soil temperatures over several years of heat collection system operation. The soil temperatures expected on the fifth year of operation were considered to be the design temperatures. The described study was performed with the financial support of the Ministry of Education and Science of Russia. Contract ID RFMEFI57914X0026.

  7. The influence of soil moisture in the unsaturated zone on the heat loss from buildings via the ground

    NARCIS (Netherlands)

    Janssen, H.; Carmeliet, J.; Hens, H.

    2002-01-01

    In calculations of building heat loss via the ground, the coupling with soil moisture transfer is generally ignored, an important hypothesis which will be falsified in this paper. Results from coupled simulations - coupled soil heat and moisture transfer equations and complete surface heat and

  8. Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating

    OpenAIRE

    Li, Xian-Xiang; Britter, Rex E.; Koh, Tieh Yong; Norford, Leslie Keith; Liu, Chun-Ho; Entekhabi, Dara; Leung, Dennis Y. C.

    2009-01-01

    Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification was produced by heating the ground of the street canyon. Using the Boussinesq approximation, thermal buoyancy forces were taken into account in both the Navier–Stokes equations and the transport equation for subgrid-scale turbulent kinetic energy (TKE). The LESs were valida...

  9. Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating

    Science.gov (United States)

    Li, Xian-Xiang; Britter, Rex E.; Koh, Tieh Yong; Norford, Leslie K.; Liu, Chun-Ho; Entekhabi, Dara; Leung, Dennis Y. C.

    2010-11-01

    Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification was produced by heating the ground of the street canyon. Using the Boussinesq approximation, thermal buoyancy forces were taken into account in both the Navier-Stokes equations and the transport equation for subgrid-scale turbulent kinetic energy (TKE). The LESs were validated against experimental data obtained in wind-tunnel studies before the model was applied to study the detailed turbulence, temperature, and pollutant dispersion characteristics in the street canyon of aspect ratio 1. The effects of different Richardson numbers ( Ri) were investigated. The ground heating significantly enhanced mean flow, turbulence, and pollutant flux inside the street canyon, but weakened the shear at the roof level. The mean flow was observed to be no longer isolated from the free stream and fresh air could be entrained into the street canyon at the roof-level leeward corner. Weighed against higher temperature, the ground heating facilitated pollutant removal from the street canyon.

  10. Composite coils for toroidal field coils and method of using same

    International Nuclear Information System (INIS)

    Perkins, R. G.; Trujillo, S. M.

    1985-01-01

    A composite toroidal field (TF) generating means consisting of segmented magnetic coil windings is disclosed. Each coil winding of the TF generating means consists of a copper or copper alloy conductor segment and an aluminum or aluminum alloy conductor segment. The conductor segments are joined at a high strength, low electrical resistance joint and the joint may either be a mechanical or metallurgical one. The use of the aluminum or aluminum alloy conductor segments improves the neutron economy of the reactor with which the TF coil is associated and reduces TF coil nuclear heating and heating gradients, and activation in the TF coils

  11. 太阳能辅助地源热泵供暖实验研究%Experimental study of a solar assisted ground source heat pump for heating

    Institute of Scientific and Technical Information of China (English)

    赵忠超; 丰威仙; 巩学梅; 米浩君; 成华; 云龙

    2014-01-01

    An experimental study is performed to determine the performance of the solar assisted ground source heat pump(SAGSHP)by using a solar-ground source heat pump hybrid system in the city of Ningbo. The result shows that comparing with the ground source heat pump(GSHP),when the ratio of solar energy to the whole en-ergy is 41. 9% ,the coefficient of performance( COP)of the heat pump and system can improve 15. 1% and 7. 7% respectively. Therefore,the solar assisted ground source heat pump has a significant performance advan-tage according to the experimental result.%选取宁波某公用建筑的太阳能-地源热泵复合系统为实验系统,对太阳能辅助地源热泵( solar assisted ground source heat pump,SAGSHP)供暖进行了实验研究.研究结果表明:与单一的地源热泵(ground source heat pump,GSHP)相比,当太阳能承担41.9%负荷时,热泵机组和整个系统的能效比(coefficient of performance,COP)分别提高了15.1%和7.7%, SAGSHP 供暖运行模式具有明显的性能优势.

  12. Temperature distributions in boreholes of a vertical ground-coupled heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23279 Elazig (Turkey); Esen, Yuksel [Department of Construction Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey)

    2009-12-15

    The objective of this study is to show the temperature distribution development in the borehole of the ground-coupled heat pump systems (GCHPs) with time. The time interval for the study is 48 h. The vertical GCHP system using R-22 as refrigerant has a three single U-tube ground heat exchanger (GHE) made of polyethylene pipe with a 40 mm outside diameter. The GHE was placed in a vertical borehole (VB) with 30 (VB1), 60 (VB2) and 90 (VB3) m depths and 150 mm diameters. The experimental results were obtained in cooling and heating seasons of 2006-2007. A two-dimensional finite element model (FEM) was developed to simulate temperature distribution development in the soil surrounding the GHEs of GCHPs operating in the cooling and the heating modes. The finite element modelling of the GCHP system was performed using the ANSYS code. The FEM incorporated pipes, the grout and the surrounding formation. From the cases studied, this approach appears to be the most promising for estimation the temperature distribution response of GHEs to thermal loading. (author)

  13. Ground source heat pump retrofit at North Bonneville, WA City Hall

    Energy Technology Data Exchange (ETDEWEB)

    Hughey, M. [Skamania Co. PUD No. 1, Carson, WA (United States)

    1997-12-31

    In 1995, the City of North Bonneville, WA installed a 10-ton Ground Source Heat Pump (GSHP) to replace the electric resistance furnace in its 4,000 square, foot City Hall. North Bonneville is 30 miles east of Portland, Oregon, at river level in the Columbia River Gorge. Funded jointly by the Bonneville Power Administration, the State of Washington and the City, this project has successfully reduced the heating cost of City Hall by nearly one-half while dramatically increasing comfort. It has become a commercial model in the Pacific Northwest for assessing values of commercial GSHP retrofits. This interim report compares estimated savings with actual experience for the first operating year. Projected savings were $1,500; actual savings were $1,390 prior to adjustment for extreme weather. Adjusted savings for Heating Year 1996 were $1,490, a 47 percent decrease. Maintenance savings (not itemized) were in addition to this amount. Monitoring continues in 1997.

  14. Ground source heat pumps versus high efficiency natural gas furnaces in Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J.

    2003-02-02

    For the past twenty years or so, the heating and cooling of numerous buildings in northern Europe has been accomplished using ground source heat pumps (GSHPs), while in North America they have been in use for approximately ten years. In the Prairies, natural gas furnaces dominate, while GSHP are more popular in eastern Canada. The author noted that natural gas furnaces have an efficiency of 80 per cent or less, while high efficiency natural gas (HENG) furnaces, more expensive, have an efficiency in the 90 per cent range. A brief outline of the principles behind GSHPs was provided. The Coefficient of Performance (COP) of GSHP reaches up to 500 per cent depending whether the unit is cooling or heating. The amount of heat produced by a heating system expressed as a percentage of the energy input required to operate the system is the definition used for the efficiency. In those cases where it is possible to amortize the initial costs, pay now or obtain a subsidy, the installation of GSHP is advantageous. Several factors affect the total cost of heating a building, such as the airtightness of the building and its insulation, the coldness of the climate, and the inside controlled temperature setting. The author then examined the cost of operating a GSHP versus a natural gas furnace. In most examples studied, the cost of operating a GSHP was less than the cost of operating a natural gas furnace. The Total Equivalent Warming Impact (TEWI) of GSHPs and HENG furnaces was examined. The author concluded that the cost of heating by GSHP in Alberta will be lower than the cost of heating by HENG which requires a separate air conditioning unit for the summer months, with additional improvements in efficiency and insulation. 7 refs., 4 tabs.

  15. Verification of the Performance of a Vertical Ground Heat Exchanger Applied to a Test House in Melbourne, Australia

    Directory of Open Access Journals (Sweden)

    Koon Beng Ooi

    2017-10-01

    Full Text Available The ground heat exchanger is traditionally used as a heat source or sink for the heat pump that raises the temperature of water to about 50 °C to heat houses. However, in winter, the heating thermostat (temperature at which heating begins in the Australian Nationwide House Energy Rating Scheme (NatHERS is only 20 °C during daytime and 15 °C at night. In South-East Melbourne, the temperature at the bottom of a 50-meter-deep borehole has been recorded with an Emerson™ recorder at 17 °C. Melbourne has an annual average temperature of 15 °C, so the ground temperature increases by 2 °C per 50-m depth. A linear projection gives 23 °C at 200-m of depth, and as the average undisturbed temperature of the ground for a 400-m-deep vertical ground heat exchanger (VGHE. This study, by simulation and experimentation, aims to verify that the circulation of water in the VGHE’s U-tube to low-temperature radiators (LTRs could heat a house to thermal comfort. A literature review is included in the introduction. A simulation, using a model of a 60-m2 experimental house, shows that the daytime circulation of water in this VGHE/LTR-on-opposite-walls system during the 8-month cold half of the year, heats the indoors to NatHERS settings. Simulation for the cold half shows that this VGHE-LTR system could cool the indoors. Instead, a fan creating a cooling sensation of up to 4 °C is used so that the VGHE is available for the regeneration of heat extracted from the ground during the cold portion. Simulations for this hot portion show that a 3.4-m2 flat plate solar collector can collect more than twice the heat extracted from the ground in the cold portion. Thus, it can thus replenish the ground heat extracted for houses double the size of this 60-m2 experimental house. Therefore, ground heat is sustainable for family-size homes. Since no heat pump is used, the cost of VGHE-LTR systems could be comparable to systems using the ground source heat pump. Water

  16. Impact of global warming on performance of ground source heat pumps in US climate zones

    International Nuclear Information System (INIS)

    Shen, Pengyuan; Lukes, Jennifer R.

    2015-01-01

    Highlights: • Used morphing method to have downscaled hourly local weather data from GCM. • Selected representative cities in different climate zones in the US for case study on GSHP performance. • Used hourly building simulation tools (eQuest and TRNSYS) to project GSHP performance in future. • Analysis on GSHP performance in 2050 for both residential and office building in the US are conducted. - Abstract: Ground source heat pumps (GSHP) have attracted increasing attention because of their high energy efficiencies. The aim of this paper is to study the performance of (GSHP) in future climate conditions (2040–2069) by using projected future hourly weather data of selected representative cities in the US to estimate future ground temperature change. The projected hourly weather data and estimated ground temperatures are input to an hourly simulation tool (TRNSYS and eQuest for this research), which provides reliable coupling of GSHP system and building performance. The simulation results show that global warming will decrease the energy efficiency of GSHP in US residential buildings because a rise in inlet and outlet water temperature is predicted for GSHP systems during the cooling season and because buildings will become more cooling dominated in the future. For office buildings, although the cooling performance of GSHP will not drop significantly under future climate, the overall energy efficiency for the system will decrease due to the increasing energy consumption of the ground loop pump. In the future, considering the significant ground heat imbalance for GSHP operation, GSHP will become less competitive both economically and technically than it is now in the context of US climate zones

  17. Superconducting cyclotron magnet coil short

    International Nuclear Information System (INIS)

    Mallory, M.L.; Blosser, H.G.; Clark, D.J.; Launer, H.; Lawton, D.; Miller, P.; Resmini, F.

    1982-01-01

    In February 1981, a short circuit appeared in the superconducting coil of the K500 cyclotron. The short is resistive in character and therefore has no effect on steady state operation of the magnet. The resistance of the short varies, sometimes being below threshold of detection as a heat load on the cooling system and sometimes being significant. The resistance under certain conditions shows approximately cyclic phenomena with time constants in the range of seconds and other approximately cyclic phenomena which correlate with gross operating parameters of the magnet (shifting current from one coil to another at high field and lowering and raising the liquid helium level). A number of diagnostic studies of the short have been made, using 1) an array of flux sensing loops to sense the magnetic effect of the short, 2) voltage comparisons between upper and lower sections of the coil, 3) comparisons of forces in the nine member coil support system and 4) the effect of the short on the thermal charactersitics of the coil. Insulation failure or a metal chip shorting out turns have been explored in some detail but a convincing determination of the exact cause of the short may never be available, (even the extreme step of unwinding the coil having a significant probability that an imperfection with the observed characteristics would pass unnoticed). Analysis of the characteristics of the short indicated that the most serious consequence would be failure of the coils mechanical support system in the event that the magnet was quickly discharged, as in a dump or quench. To deal with this hazard, the support system has been modified by installing solid supports which prevent the coil from moving by an amount sufficient to damage the support system. We have also reexamined the data and calculations used in the original coil design and have made some additional measurements of the properties of the materials (yield strength, friction coefficient, Young's modulus) used in the

  18. Experimental study on the losses and magnetic fields of coils inside a metallic liner for T.T.M.P. heating application

    International Nuclear Information System (INIS)

    Brossaud, J.; Perin, J.P.; Rey, G.

    1978-11-01

    The purpose of this work is the improvement of the T.T.M.P. configuration in the Tokamak PETULA in the case of one or three wavelengths. The variation of the magnetic field distribution and the electrical characteristics coils (R//,Q, L) inside a metallic liner have been studied as functions of: position and number of coils, radius and width of coils, number of wavelengths along the axis of torus [fr

  19. Quantification of exploitable shallow geothermal energy by using Borehole Heat Exchanger coupled Ground Source Heat Pump systems

    International Nuclear Information System (INIS)

    Hein, Philipp; Zhu, Ke; Bucher, Anke; Kolditz, Olaf; Pang, Zhonghe; Shao, Haibing

    2016-01-01

    Highlights: • The amount of technically exploitable shallow geothermal energy was quantified. • Therefore, a comprehensive numerical borehole heat exchanger model was employed. • The concept of equivalent temperature drop is introduced. • For one BHE, an equivalent temperature drop of 1.8–2.8 °C over 30 years is realistic • The average extractable energy amount evaluates to be 3.5–5.4 kW h m"−"2 a"−"1. - Abstract: In previous studies, the amount of exploitable shallow geothermal energy was estimated by assuming a uniform temperature drop of 2–6 °C in the aquifer. In this work, a more comprehensive numerical model has been employed to evaluate the available amount of shallow geothermal energy by using Borehole Heat Exchanger coupled Ground Source Heat Pump systems. Numerical experiments have been performed by simulating the long-term evolution of the subsurface temperature field, which is subject to the operation of borehole heat exchangers and varying parameters like subsurface thermal conductivity and groundwater flow velocity. The concept of equivalent temperature drop is proposed as an auxiliary quantity for the subsurface. With the help of this parameter, a procedure has been established to quantify the amount of shallow geothermal potential. Following this approach, a realistic equivalent temperature reduction is found to be from −1.8 to −4.4 °C in the subsurface over a period of 30 years. This can be translated to an annual extractable geothermal energy value in a unit surface area, and it ranges from 3.5 to 8.6 kW h m"−"2 a"−"1. The exact value is site specific and heavily depends on the soil thermal conductivity, groundwater velocity, and borehole arrangement.

  20. Ground test program for a full-size solar dynamic heat receiver

    Science.gov (United States)

    Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

    1991-01-01

    Test hardware, facilities, and procedures were developed to conduct ground testing of a full-size, solar dynamic heat receiver in a partially simulated, low earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment was designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed-Brayton cycle engine simulator to circulate and condition the helium-xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

  1. Case study for ARRA-funded ground-source heat pump (GSHP) demonstration at Oakland University

    Energy Technology Data Exchange (ETDEWEB)

    Im, Piljae [ORNL; Liu, Xiaobing [ORNL

    2015-09-01

    High initial costs and lack of public awareness of ground-source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy-saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects have been competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This paper highlights the findings of a case study of one of the ARRA-funded GSHP demonstration projects, a ground-source variable refrigerant flow (GS-VRF) system installed at the Human Health Building at Oakland University in Rochester, Michigan. This case study is based on the analysis of measured performance data, maintenance records, construction costs, and simulations of the energy consumption of conventional central heating, ventilation, and air-conditioning (HVAC) systems providing the same level of space conditioning as the demonstrated GS-VRF system. The evaluated performance metrics include the energy efficiency of the heat pump equipment and the overall GS-VRF system, pumping performance, energy savings, carbon emission reductions, and cost-effectiveness of the GS-VRF system compared with conventional HVAC systems. This case study also identified opportunities for reducing uncertainties in the performance evaluation, improving the operational efficiency, and reducing the installed cost of similar GSHP systems in the future.

  2. DEA (data envelopment analysis)-assisted supporting measures for ground coupled heat pumps implementing in Italy: A case study

    International Nuclear Information System (INIS)

    Longo, L.; Colantoni, A.; Castellucci, S.; Carlini, M.; Vecchione, L.; Savuto, E.; Pallozzi, V.; Di Carlo, A.; Bocci, E.; Moneti, M.; Cocchi, S.; Boubaker, K.

    2015-01-01

    Nowadays, the increasing of the energy consumption is producing serious global warming issues. Mainly most of greenhouse gas emissions in developed countries come from building equipments. In this context, GCHPs (ground coupled heat pumps) are candidate solution as air conditioning systems in buildings due to their higher efficiency compared to conventional devices. Actually, ground coupled heat pump systems are widely, recognized among the most efficient and comfortable used systems. Nevertheless, economic efficiency of the ground coupled heat pumps has to be proved. In this study, DEA (data envelopment analyses) method is applied to a real case in Italy. - Highlights: • Original investigation in terms of energy demands in buildings. • Gathering conjoint classical and scientific analyses. • Presenting original DEA (data envelopment analysis) economic optimization scheme analyses. • Outlining economical feasibility of an efficient low enthalpy-geothermal plant with GCHP (ground coupled heat pump) exchangers.

  3. Optimization of systems with the combination of ground-source heat pump and solar collectors in dwellings

    DEFF Research Database (Denmark)

    Kjellsson, Elisabeth; Hellström, Göran; Perers, Bengt

    2010-01-01

    The use of ground-source heat pumps for heating and domestic hot water in dwellings is common in Sweden. The combination with solar collectors has been introduced to reduce the electricity demand in the system. In order to analyze different systems with combinations of solar collectors and ground......-source heat pumps, computer simulations have been carried out with the simulation program TRNSYS. Large differences were found between the system alternatives. The optimal design is when solar heat produces domestic hot water during summertime and recharges the borehole during wintertime. The advantage...... is related to the rate of heat extraction from the borehole as well as the overall design of the system. The demand of electricity may increase with solar recharging, because of the increased operating time of the circulation pumps. Another advantage with solar heat in combination with heat pumps is when...

  4. Design of the coolant system for the Large Coil Test Facility pulse coils

    International Nuclear Information System (INIS)

    Bridgman, C.; Ryan, T.L.

    1983-01-01

    The pulse coils will be a part of the Large Coil Test Facility in Oak Ridge, Tennessee, which is designed to test six large tokamak-type superconducting coils. The pulse coil set consists of two resistive coaxial solenoid coils, mounted so that their magnetic axis is perpendicular to the toroidal field lines of the test coil. The pulse coils provide transient vertical fields at test coil locations to simulate the pulsed vertical fields present in tokamak devices. The pulse coils are designed to be pulsed for 30 s every 150 s, which results in a Joule heating of 116 kW per coil. In order to provide this capability, the pulse coil coolant system is required to deliver 6.3 L/s (100 gpm) of subcooled liquid nitrogen at 10-atm absolute pressure. The coolant system can also cool down each pulse coil from room temperature to liquid nitrogen temperature. This paper provides details of the pumping and heat exchange equipment designed for the coolant system and of the associated instrumentation and controls

  5. Ground-source heat pump barometer - EurObserv'ER - September 2011

    International Nuclear Information System (INIS)

    2011-09-01

    2,9% slide by the GHSP market in the EU between 2009 and 2010. The double whammy dealt by the economic crisis and housing slump has stifled expansion of the ground-source heat pump market in many European countries. The European Union market contracted for the second year running (by 2.9% between 2009 and 2010), and this despite the fact that more than 100 000 units were sold over the twelve-month period, taking the number of installed units past the one million mark

  6. Horizontal Air-Ground Heat Exchanger Performance and Humidity Simulation by Computational Fluid Dynamic Analysis

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2016-11-01

    Full Text Available Improving energy efficiency in buildings and promoting renewables are key objectives of European energy policies. Several technological measures are being developed to enhance the energy performance of buildings. Among these, geothermal systems present a huge potential to reduce energy consumption for mechanical ventilation and cooling, but their behavior depending on varying parameters, boundary and climatic conditions is not fully established. In this paper a horizontal air-ground heat exchanger (HAGHE system is studied by the development of a computational fluid dynamics (CFD model. Summer and winter conditions representative of the Mediterranean climate are analyzed to evaluate operation and thermal performance differences. A particular focus is given to humidity variations as this parameter has a major impact on indoor air quality and comfort. Results show the benefits that HAGHE systems can provide in reducing energy consumption in all seasons, in summer when free-cooling can be implemented avoiding post air treatment using heat pumps.

  7. Case Study for the ARRA-Funded Ground Source Heat Pump Demonstration at Ball State University

    Energy Technology Data Exchange (ETDEWEB)

    Im, Piljae [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Xiaobing [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Henderson, Jr., Hugh [CDH Energy Corp., Beijing (China)

    2016-12-01

    With funding provided by the American Recovery and Reinvestment Act (ARRA), 26 ground-source heat pump (GSHP) projects were competitively selected in 2009 to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. One of the selected demonstration projects is a district central GSHP system installed at Ball State University (BSU) in Muncie, IN. Prior to implementing the district GSHP system, 47 major buildings in BSU were served by a central steam plant with four coal-fired and three natural-gas-fired steam boilers. Cooling was provided by five water-cooled centrifugal chillers at the District Energy Station South (DESS). The new district GSHP system replaced the existing coal-fired steam boilers and conventional water-cooled chillers. It uses ground-coupled heat recovery (HR) chillers to meet the simultaneous heating and cooling demands of the campus. The actual performance of the GSHP system was analyzed based on available measured data from August 2015 through July 2016, construction drawings, maintenance records, personal communications, and construction costs. Since Phase 1 was funded in part by the ARRA grant, it is the focus of this case study. The annual energy consumption of the GSHP system was calculated based on the available measured data and other related information. It was compared with the performance of a baseline scenario— a conventional water-cooled chiller and natural-gas-fired boiler system, both of which meet the minimum energy efficiencies allowed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE 90.1-2013). The comparison was made to determine source energy savings, energy cost savings, and CO2 emission reductions achieved by the GSHP system. A cost analysis was performed to evaluate the simple payback of the GSHP system. The following sections summarize the results of the analysis, the lessons learned, and recommendations for improvement

  8. Strategic GHG reduction through the use of ground source heat pump technology

    International Nuclear Information System (INIS)

    Hanova, J; Dowlatabadi, H

    2007-01-01

    Higher energy prices and concern about climate change is drawing increasing attention to ground source heat pump (GSHP) systems. Their clear advantage lies in being able to provide heating using 25 to 30% of the energy consumed by even the most efficient conventional alternatives. Their drawback has been high capital costs and uncertainty about whether the emissions associated with the electric power used to energise the system has higher system-wide emissions than the highest-efficiency furnaces. This study delineates circumstances under which GSHP systems achieve net emission reductions, for different electricity generation methods, heat pump efficiencies, and heating loads. We illustrate the effect of relative fuel prices on annual operating savings using fuel prices in multiple countries. Annual operating savings determine how rapidly the technology achieves payback and then generates return on the initial capital investment. Finally, we highlight the least cost supply curve for using GSHP to reduce greenhouse gas emissions. Using the United States as a base reference case, this study explores the potential of GSHP in cold-climate countries worldwide

  9. Feasibility of ground coupled heat pumps in office buildings: A China study

    International Nuclear Information System (INIS)

    Zhou, Zhihua; Zhang, Zhiming; Chen, Guanyi; Zuo, Jian; Xu, Pan; Meng, Chong; Yu, Zhun

    2016-01-01

    Highlights: • Feasibility of GCHPs in office buildings was assessed in various climatic regions. • Performance of GCHPs was compared with traditional heating and cooling techniques. • Ratio of the heating to cooling load has significant impacts on operation of GCHPs. - Abstract: Ground coupled heat pumps (GCHPs) have been widely applied in China due to its environmental friendliness and energy efficiency. However, it may not be appropriate in all geographical areas because a variety of factors (e.g. original soil temperature, peak cooling and heating load, and running time) vary significantly. Typical office buildings were selected from five cities that are located in different climatic regions. The QUick Energy Simulation Tool (e-QUEST) was utilized to simulate the cooling and heating load. Similarly, the Transient System Simulation Program (TRNSYS) was employed to simulate the 20-year variation of the average soil temperature and the Coefficient of Performance (COP) of GCHP units. Consequently, the feasibility of the GCHPs in different regions was analyzed. The results show that GCHP system is feasible in severe cold B regions such as Shenyang and cold regions such as Beijing as both cold and heat sources because of its energy efficiency. From the economy and operation performance’s perspective, GCHP system is not feasible in severe cold A regions such as Harbin; hot-summer and cold-winter regions such as Nanjing; and hot-summer and warm-winter region such as Guangzhou. This is due to the poor energy efficiency of the system, mainly attributed to a large gap between cumulative energy consumption for cooling and for heating. Comprehensive analysis of experiment results showed that the GCHP system of case building in cold region can operate stably in long term with a high efficiency when the ratio of annual cumulative cooling energy consumption to annual cumulative heating energy consumption ranges from 0.2:1 to 5:1. In severe cold B regions, GCHP system

  10. Heat shock and thermotolerance of Escherichia coli O157:H7 in a model beef gravy system and ground beef.

    Science.gov (United States)

    Juneja, V K; Klein, P G; Marmer, B S

    1998-04-01

    Duplicate beef gravy or ground beef samples inoculated with a suspension of a four-strain cocktail of Escherichia coli O157:H7 were subjected to sublethal heating at 46 degrees C for 15-30 min, and then heated to a final internal temperature of 60 degrees C. Survivor curves were fitted using a linear model that incorporated a lag period (TL), and D-values and 'time to a 4D inactivation' (T4D) were calculated. Heat-shocking allowed the organism to survive longer than non-heat-shocked cells; the T4D values at 60 degrees C increased 1.56- and 1.50-fold in beef gravy and ground beef, respectively. In ground beef stored at 4 degrees C, thermotolerance was lost after storage for 14 h. However, heat-shocked cells appeared to maintain their thermotolerance for at least 24 h in ground beef held to 15 or 28 degrees C. A 25 min heat shock at 46 degrees C in beef gravy resulted in an increase in the levels of two proteins with apparent molecular masses of 60 and 69 kDa. These two proteins were shown to be immunologically related to GroEL and DnaK, respectively. Increased heat resistance due to heat shock must be considered while designing thermal processes to assure the microbiological safety of thermally processed foods.

  11. ANL experimental program for pulsed superconducting coils

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1978-01-01

    Argonne National Laboratory (ANL) had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and started in aggressive development program in FY 1977. The main objectives for FY 1977 are to develop cryostable basic cable configurations with reasonably low ac losses, to develop 12 kA cryostable cable, using it to design and build a 1.5 MJ pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat for the 1.5 MJ pulsed coil. The principal objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil ranging from 2 T/s up to 12 T/s. Another objective in the pulsed coil program is to determine the feasibility of parallel coil operation in order to avoid excessive voltage and current requirements and to minimize the number of turns for the equilibrium field (EF) coils, should the EF coils be connected in parallel with the OH coils. A two-coil section model using the 11 kA cable will be built and tested

  12. ANL experimental program for pulsed superconducting coils

    International Nuclear Information System (INIS)

    Wang, S.T.; Kim, S.H.; Praeg, W.F.; Krieger, C.I.

    1977-01-01

    Argonne National Laboratory (ANL) had recognized the clear advantage of a superconducting ohmic-heating (OH) coil and started an aggressive development program in FY 1977. The main objectives for FY 1977 are to develop cryostable basic cable configurations with reasonably low ac losses, to develop 12 kA cryostable cable, using it to design and build a 1.5 MJ pulsed coil, and to develop a rather inexpensive large fiberglass reinforced helium cryostat for the 1.5 MJ pulsed coil. The principal objective in building the 1.5 MJ ac coil is to demonstrate ac cryostability of a large coil ranging from 2 T/s up to 12 T/s. Another objective in the pusled coil program is to determine the feasibility of parallel coil operation in order to avoid excessive voltage and current requirements and to minimize the number of turns for the equilibrium field (EF) coils, should the EF coils be connected in parallel with the OH coils. A two-coil section model using the 11 kA cable will be built and tested

  13. An Experimental Facility to Validate Ground Source Heat Pump Optimisation Models for the Australian Climate

    Directory of Open Access Journals (Sweden)

    Yuanshen Lu

    2017-01-01

    Full Text Available Ground source heat pumps (GSHPs are one of the most widespread forms of geothermal energy technology. They utilise the near-constant temperature of the ground below the frost line to achieve energy-efficiencies two or three times that of conventional air-conditioners, consequently allowing a significant offset in electricity demand for space heating and cooling. Relatively mature GSHP markets are established in Europe and North America. GSHP implementation in Australia, however, is limited, due to high capital price, uncertainties regarding optimum designs for the Australian climate, and limited consumer confidence in the technology. Existing GSHP design standards developed in the Northern Hemisphere are likely to lead to suboptimal performance in Australia where demand might be much more cooling-dominated. There is an urgent need to develop Australia’s own GSHP system optimisation principles on top of the industry standards to provide confidence to bring the GSHP market out of its infancy. To assist in this, the Queensland Geothermal Energy Centre of Excellence (QGECE has commissioned a fully instrumented GSHP experimental facility in Gatton, Australia, as a publically-accessible demonstration of the technology and a platform for systematic studies of GSHPs, including optimisation of design and operations. This paper presents a brief review on current GSHP use in Australia, the technical details of the Gatton GSHP facility, and an analysis on the observed cooling performance of this facility to date.

  14. Multi-objective optimization of a vertical ground source heat pump using evolutionary algorithm

    International Nuclear Information System (INIS)

    Sayyaadi, Hoseyn; Amlashi, Emad Hadaddi; Amidpour, Majid

    2009-01-01

    Thermodynamic and thermoeconomic optimization of a vertical ground source heat pump system has been studied. A model based on the energy and exergy analysis is presented here. An economic model of the system is developed according to the Total Revenue Requirement (TRR) method. The objective functions based on the thermodynamic and thermoeconomic analysis are developed. The proposed vertical ground source heat pump system including eight decision variables is considered for optimization. An artificial intelligence technique known as evolutionary algorithm (EA) has been utilized as an optimization method. This approach has been applied to minimize either the total levelized cost of the system product or the exergy destruction of the system. Three levels of optimization including thermodynamic single objective, thermoeconomic single objective and multi-objective optimizations are performed. In Multi-objective optimization, both thermodynamic and thermoeconomic objectives are considered, simultaneously. In the case of multi-objective optimization, an example of decision-making process for selection of the final solution from available optimal points on Pareto frontier is presented. The results obtained using the various optimization approaches are compared and discussed. Further, the sensitivity of optimized systems to the interest rate, to the annual number of operating hours and to the electricity cost are studied in detail.

  15. Development of a new error field correction coil (C-coil) for DIII-D

    International Nuclear Information System (INIS)

    Robinson, J.I.; Scoville, J.T.

    1995-12-01

    The C-coil recently installed on the DIII-D tokamak was developed to reduce the error fields created by imperfections in the location and geometry of the existing coils used to confine, heat, and shape the plasma. First results from C-coil experiments include stable operation in a 1.6 MA plasma with a density less than 1.0 x 10 13 cm -3 , nearly a factor of three lower density than that achievable without the C-coil. The C-coil has also been used in magnetic braking of the plasma rotation and high energy particle confinement experiments. The C-coil system consists of six individual saddle coils, each 60 degree wide toroidally, spanning the midplane of the vessel with a vertical height of 1.6 m. The coils are located at a major radius of 3.2 m, just outside of the toroidal field coils. The actual shape and geometry of each coil section varied somewhat from the nominal dimensions due to the large number of obstructions to the desired coil path around the already crowded tokamak. Each coil section consists of four turns of 750 MCM insulated copper cable banded with stainless steel straps within the web of a 3 in. x 3 in. stainless steel angle frame. The C-coil structure was designed to resist peak transient radial forces (up to 1,800 Nm) exerted on the coil by the toroidal and ploidal fields. The coil frames were supported from existing poloidal field coil case brackets, coil studs, and various other structures on the tokamak

  16. Characterization of Site for Installing Open Loop Ground Source Heat Pump System

    Science.gov (United States)

    Yun, S. W.; Park, Y.; Lee, J. Y.; Yi, M. J.; Cha, J. H.

    2014-12-01

    This study was conducted to understand hydrogeological properties of site where open loop ground source heat pump system will be installed and operated. Groundwater level and water temperature were hourly measured at the well developed for usage of open loop ground source heat pump system from 11 October 2013 to 8 January 2014. Groundwater was sampled in January and August 2013 and its chemical and isotopic compositions were analyzed. The bedrock of study area is the Jurassic granodiorite that mainly consists of quartz (27.9 to 46.8%), plagioclase (26.0 to 45.5%), and alkali feldspar (9.5 to 18.7%). The groundwater level ranged from 68.30 to 68.94 m (above mean sea level). Recharge rate was estimated using modified watertable fluctuation method and the recharge ratios was 9.1%. The water temperature ranged from 14.8 to 15.0oC. The vertical Increase rates of water temperature were 1.91 to 1.94/100 m. The water temperature showed the significant seasonal variation above 50 m depth, but had constant value below 50 m depth. Therefore, heat energy of the groundwater can be used securely in open loop ground source heat pump system. Electrical conductivity ranged from 120 to 320 µS/cm in dry season and from 133 to 310 µS/cm in wet season. The electrical conductivity gradually decreased with depth. In particular, electrical conductivity in approximately 30 m depth decreased dramatically (287 to 249 µS/cm) in wet season. The groundwater was Ca-HCO3 type. The concentrations of dissolved components did not show the vertically significant variations from 0 to 250 m depth. The δ18O and δD ranged from -9.5 to -9.4‰ and from -69 to -68‰. This work is supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).

  17. Modelling a ground-coupled heat pump system using adaptive neuro-fuzzy inference systems

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23279 Elazig (Turkey); Sengur, Abdulkadir [Department of Electronic and Computer Science, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey)

    2008-01-15

    The aim of this study is to demonstrate the usefulness of an adaptive neuro-fuzzy inference system (ANFIS) for the modelling of ground-coupled heat pump (GCHP) system. The GCHP system connected to a test room with 16.24 m{sup 2} floor area in Firat University, Elazig (38.41 N, 39.14 E), Turkey, was designed and constructed. The heating and cooling loads of the test room were 2.5 and 3.1 kW at design conditions, respectively. The system was commissioned in November 2002 and the performance tests have been carried out since then. The average performance coefficients of the system (COPS) for horizontal ground heat exchanger (GHE) in the different trenches, at 1 and 2 m depths, were obtained to be 2.92 and 3.2, respectively. Experimental performances were performed to verify the results from the ANFIS approach. In order to achieve the optimal result, several computer simulations have been carried out with different membership functions and various number of membership functions. The most suitable membership function and number of membership functions are found as Gauss and 2, respectively. For this number level, after the training, it is found that root-mean squared (RMS) value is 0.0047, and absolute fraction of variance (R{sup 2}) value is 0.9999 and coefficient of variation in percent (cov) value is 0.1363. This paper shows that the values predicted with the ANFIS, especially with the hybrid learning algorithm, can be used to predict the performance of the GCHP system quite accurately. (author)

  18. Hybrid Ground-Source Heat Pump Installations: Experiences, Improvements, and Tools

    Energy Technology Data Exchange (ETDEWEB)

    Scott Hackel; Amanda Pertzborn

    2011-06-30

    One innovation to ground-source heat pump (GSHP, or GHP) systems is the hybrid GSHP (HyGSHP) system, which can dramatically decrease the first cost of GSHP systems by using conventional technology (such as a cooling tower or a boiler) to meet a portion of the peak heating or cooling load. This work uses three case studies (two cooling-dominated, one heating-dominated) to demonstrate the performance of the hybrid approach. Three buildings were studied for a year; the measured data was used to validate models of each system. The models were used to analyze further improvements to the hybrid approach, and establish that this approach has positive impacts, both economically and environmentally. Lessons learned by those who design and operate the systems are also documented, including discussions of equipment sizing, pump operation, and cooling tower control. Finally, the measured data sets and models that were created during this work are described; these materials have been made freely available for further study of hybrid systems.

  19. Remote sensing of the lightning heating effect duration with ground-based microwave radiometer

    Science.gov (United States)

    Jiang, Sulin; Pan, Yun; Lei, Lianfa; Ma, Lina; Li, Qing; Wang, Zhenhui

    2018-06-01

    Artificially triggered lightning events from May 26, 2017 to July 16, 2017 in Guangzhou Field Experiment Site for Lightning Research and Test (GFESL) were intentionally remotely sensed with a ground-based microwave radiometer for the first time in order to obtain the features of lightning heating effect. The microwave radiometer antenna was adjusted to point at a certain elevation angle towards the expected artificially triggered lightning discharging path. Eight of the 16 successfully artificially triggered lightning events were captured and the brightness temperature data at four frequencies in K and V bands were obtained. The results from data time series analysis show that artificially triggered lightning can make the radiometer generate brightness temperature pulses, and the amplitudes of these pulses are in the range of 2.0 K to 73.8 K. The brightness temperature pulses associated with 7 events can be used to estimate the duration of lightning heating effect through accounting the number of the pulses in the continuous pulse sequence and the sampling interval between four frequencies. The maximum duration of the lightning heating effect is 1.13 s, the minimum is 0.172 s, and the average is 0.63 s.

  20. SWIFT BAT Loop Heat Pipe Thermal System Characteristics and Ground/Flight Operation Procedure

    Science.gov (United States)

    Choi, Michael K.

    2003-01-01

    The SWIFT Burst Alert Telescope (BAT) Detector Array has a total power dissipation of 208 W. To meet the stringent temperature gradient and thermal stability requirements in the normal operational mode, and heater power budget in both the normal operational and safehold modes, the Detector Array is thermally well coupled to eight constant conductance heat pipes (CCHPs) embedded in the Detector Array Plate (DAP), and two loop heat pipes (LHPs) transport heat fiom the CCHPs to a radiator. The CCHPs have ammonia as the working fluid and the LHPs have propylene as the working fluid. Precision heater controllers, which have adjustable set points in flight, are used to control the LHP compensation chamber and Detector Array XA1 ASIC temperatures. The radiator has the AZ-Tek AZW-LA-II low-alpha white paint as the thermal coating and is located on the anti-sun side of the spacecraft. This paper presents the characteristics, ground operation and flight operation procedures of the LHP thermal system.

  1. Focus group discussions among owners and non-owners of ground source heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Roberson, B.F.

    1988-07-01

    This research was sponsored by the Office of Buildings and Community Systems and conducted by the Pacific Northwest Laboratory as part of an ongoing effort to enhance the commercial use of federally developed technology. Federal dollars have supported research on the development of ground source heat pumps (GSHP) for several years. Though several companies currently sell GSHP's for residential use, their share of the total heating and air conditioning business remains less than one percent. Large manufacturing companies with national distribution have not yet added GSHP equipment to their product line. GSHP's use only about one half (Braud 1987) to one third (Bose 1987) of the energy needed to operate conventional furnaces and air conditioners. Consequently, a high level of market penetration by the GSHP offers direct benefits to both utility companies and individual users of the systems. Widespread use of these highly efficient systems will reduce both total energy consupmtion, and problems associated with high levels of energy use during peak periods. This will allow utility companies to delay capital expenditures for new facilities to meet the growing energy demand during peak periods. The cost effective use of electricity also reduces the likelihood of homeowners switching to a different fuel source for heating. 5 refs.

  2. A quasi-transient model of a transcritical carbon dioxide direct-expansion ground source heat pump for space and water heating

    International Nuclear Information System (INIS)

    Eslami-Nejad, Parham; Ouzzane, Mohamed; Aidoun, Zine

    2015-01-01

    In this study, a theoretical quasi-transient model is developed for detailed simulations of a carbon dioxide (CO_2) direct-expansion ground source heat pump (DX-GSHP). This model combines a transient analytical model for the ground, steady-state numerical models for the borehole and the gas cooler, as well as several thermodynamic models for the remaining components of a conventional heat pump, organized in interacting subroutines to form a powerful simulation tool. Extensive validation combining experimental data and CFD-generated results was performed for the borehole before the tool was used to simulate a practical application case. Performance is investigated for a system satisfying both space heating and domestic hot water requirements of a typical single family detached home in a cold climate region. The variation of different system parameters is also evaluated in this study. It is shown that CO_2 DX-GSHPs can offer relatively efficient and stable performance for integrated water and space heating applications. Furthermore, the importance of an accurate geothermal borehole sizing is highlighted for the DX-CO_2 heat pump systems. It is shown that, due to changes in the system working conditions, the total borehole length is not linearly correlated with the heat pump energy consumption and other parameters such as heat pump coefficient of performance and pressure drop in ground heat exchangers. Results showed that increasing the total borehole length of an optimum design (reference case study) by 25% decreases the total annual energy consumption by only 6%. However, reducing total borehole length of the reference case by 25% increases the total annual energy consumption by 10%. - Highlights: • A quasi-transient model for CO_2 direct-exchange ground-source heat pump is developed. • Validation combining experimental data and CFD-generated results was performed. • The effect of the borehole size on the design parameters is evaluated. • Results show that

  3. Modeling of Rocket Fuel Heating and Cooling Processes in the Interior Receptacle Space of Ground-Based Systems

    Directory of Open Access Journals (Sweden)

    K. I. Denisova

    2016-01-01

    Full Text Available The propellant to fill the fuel tanks of the spacecraft, upper stages, and space rockets on technical and ground-based launch sites before fueling should be prepared to ensure many of its parameters, including temperature, in appropriate condition. Preparation of fuel temperature is arranged through heating and cooling the rocket propellants (RP in the tanks of fueling equipment. Processes of RP temperature preparation are the most energy-intensive and timeconsuming ones, which require that a choice of sustainable technologies and modes of cooling (heating RP provided by the ground-based equipment has been made through modeling of the RP [1] temperature preparation processes at the stage of design and operation of the groundbased fueling equipment.The RP temperature preparation in the tanks of the ground-based systems can be provided through the heat-exchangers built-in the internal space and being external with respect to the tank in which antifreeze, air or liquid nitrogen may be used as the heat transfer media. The papers [1-12], which note a promising use of the liquid nitrogen to cool PR, present schematic diagrams and modeling systems for the RP temperature preparation in the fueling equipment of the ground-based systems.We consider the RP temperature preparation using heat exchangers to be placed directly in RP tanks. Feeding the liquid nitrogen into heat exchanger with the antifreeze provides the cooling mode of PR while a heated air fed there does that of heating. The paper gives the systems of equations and results of modeling the processes of RP temperature preparation, and its estimated efficiency.The systems of equations of cooling and heating RP are derived on the assumption that the heat exchange between the fuel and the antifreeze, as well as between the storage tank and the environment is quasi-stationary.The paper presents calculation results of the fuel temperature in the tank, and coolant temperature in the heat exchanger, as

  4. ITER Side Correction Coil Quench model and analysis

    Science.gov (United States)

    Nicollet, S.; Bessette, D.; Ciazynski, D.; Duchateau, J. L.; Gauthier, F.; Lacroix, B.

    2016-12-01

    Previous thermohydraulic studies performed for the ITER TF, CS and PF magnet systems have brought some important information on the detection and consequences of a quench as a function of the initial conditions (deposited energy, heated length). Even if the temperature margin of the Correction Coils is high, their behavior during a quench should also be studied since a quench is likely to be triggered by potential anomalies in joints, ground fault on the instrumentation wires, etc. A model has been developed with the SuperMagnet Code (Bagnasco et al., 2010) for a Side Correction Coil (SCC2) with four pancakes cooled in parallel, each of them represented by a Thea module (with the proper Cable In Conduit Conductor characteristics). All the other coils of the PF cooling loop are hydraulically connected in parallel (top/bottom correction coils and six Poloidal Field Coils) are modeled by Flower modules with equivalent hydraulics properties. The model and the analysis results are presented for five quench initiation cases with/without fast discharge: two quenches initiated by a heat input to the innermost turn of one pancake (case 1 and case 2) and two other quenches initiated at the innermost turns of four pancakes (case 3 and case 4). In the 5th case, the quench is initiated at the middle turn of one pancake. The impact on the cooling circuit, e.g. the exceedance of the opening pressure of the quench relief valves, is detailed in case of an undetected quench (i.e. no discharge of the magnet). Particular attention is also paid to a possible secondary quench detection system based on measured thermohydraulic signals (pressure, temperature and/or helium mass flow rate). The maximum cable temperature achieved in case of a fast current discharge (primary detection by voltage) is compared to the design hot spot criterion of 150 K, which includes the contribution of helium and jacket.

  5. Combined heat and cold generation using vertical ground loops; Gekoppelte Kaelte- und Waermeerzeugung mit Erdwaermesonden: Handbuch zum Planungsvorgehen

    Energy Technology Data Exchange (ETDEWEB)

    Good, J.; Nussbaumer, T. [Ingenieurbuero Verenum, Zuerich (Switzerland); Huber, A.; Widmer, P. [Huber Energietechnik, Zuerich (Switzerland); Truessel, D. [Kaelte-Waerme-Technik AG, Belp (Switzerland); Schmid, Ch. [Buero fuer Energietechnik, Winterthur (Switzerland)

    2001-07-01

    This handbook produced for the Swiss Federal Office of Energy (SFOE) addresses the problem of designing systems that produce heat and cold using integrated systems. The idea of using a single heat pump system instead of separate heating and refrigeration systems is introduced. Typical applications such as bakeries, restaurants and grocery stores are discussed. The use of vertical bore-hole heat-exchangers as a source of heat in winter and as a source of cold in summer is recommended. The handbook shows how heating and cooling needs can be calculated and examines the energy balance of a ground-coupled heat pump system. The design and calculation of an integrated system is described. A practical example of a system realised in a motor way restaurant near Berne, Switzerland, is given. Here, a heat pump-based system produces cold for refrigeration and heat for space heating and hot water. To enable comparisons to be made between different systems, the notions of energy efficiency ratio for heating and cooling (GLZ) and performance efficiency ratio for heating and cooling (GAZ) are introduced. An appendix provides useful information on simulation tools, temperature characteristics, the calculation of hot water demands, heat recovery and details on the energy consumption of refrigeration and deep-freeze equipment.

  6. Flow and Pollutant Transport in Urban Street Canyons of Different Aspect Ratios with Ground Heating: Large-Eddy Simulation

    Science.gov (United States)

    Li, Xian-Xiang; Britter, Rex E.; Norford, Leslie K.; Koh, Tieh-Yong; Entekhabi, Dara

    2012-02-01

    A validated large-eddy simulation model was employed to study the effect of the aspect ratio and ground heating on the flow and pollutant dispersion in urban street canyons. Three ground-heating intensities (neutral, weak and strong) were imposed in street canyons of aspect ratio 1, 2, and 0.5. The detailed patterns of flow, turbulence, temperature and pollutant transport were analyzed and compared. Significant changes of flow and scalar patterns were caused by ground heating in the street canyon of aspect ratio 2 and 0.5, while only the street canyon of aspect ratio 0.5 showed a change in flow regime (from wake interference flow to skimming flow). The street canyon of aspect ratio 1 does not show any significant change in the flow field. Ground heating generated strong mixing of heat and pollutant; the normalized temperature inside street canyons was approximately spatially uniform and somewhat insensitive to the aspect ratio and heating intensity. This study helps elucidate the combined effects of urban geometry and thermal stratification on the urban canyon flow and pollutant dispersion.

  7. Thermal power and heat energy of cloud-to-ground lightning process

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuejuan; Yuan, Ping; Xue, Simin [Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Cen, Jianyong [School of Physics and Information Engineering, Shanxi Normal University, Linfen 041004 (China)

    2016-07-15

    A cloud-to-ground lightning flash with nine return strokes has been recorded using a high speed slitless spectrograph and a system composed of a fast antenna and a slow antenna. Based on the spectral data and the synchronous electric field changes that were caused by the lightning, the electrical conductivity, the channel radii, the resistance per unit length, the peak current, the thermal power at the instant of peak current, and the heat energy per unit length during the first 5 μs in the discharge channel have all been calculated. The results indicate that the channel radii have linear relationships with the peak current. The thermal power at the peak current time increases with increasing resistance, but exponential decays with the square of the peak current.

  8. Highly macroscopically degenerated single-point ground states as source of specific heat capacity anomalies in magnetic frustrated systems

    Science.gov (United States)

    Jurčišinová, E.; Jurčišin, M.

    2018-04-01

    Anomalies of the specific heat capacity are investigated in the framework of the exactly solvable antiferromagnetic spin- 1 / 2 Ising model in the external magnetic field on the geometrically frustrated tetrahedron recursive lattice. It is shown that the Schottky-type anomaly in the behavior of the specific heat capacity is related to the existence of unique highly macroscopically degenerated single-point ground states which are formed on the borders between neighboring plateau-like ground states. It is also shown that the very existence of these single-point ground states with large residual entropies predicts the appearance of another anomaly in the behavior of the specific heat capacity for low temperatures, namely, the field-induced double-peak structure, which exists, and should be observed experimentally, along with the Schottky-type anomaly in various frustrated magnetic system.

  9. Ground-water heat pumps: an examination of hydrogeologic, environmental, legal, and economic factors affecting their use

    Energy Technology Data Exchange (ETDEWEB)

    Armitage, D M; Bacon, D J; Massey-Norton, J T; Miller, J D

    1980-11-12

    Groundwater is attractive as a potential low-temperature energy source in residential space-conditioning applications. When used in conjuncton with a heat pump, ground water can serve as both a heat source (for heating) and a heat sink (for cooling). Major hydrogeologic aspects that affect system use include groundwater temperature and availability at shallow depths as these factors influence operational efficiency. Ground-water quality is considered as it affects the performance and life-expectancy of the water-side heat exchanger. Environmental impacts related to groundwater heat pump system use are most influenced by water use and disposal methods. In general, recharge to the subsurface (usually via injection wells) is recommended. Legal restrictions on system use are often stricter at the municipal and county levels than at state and Federal levels. Although Federal regulations currently exist, the agencies are not equipped to regulate individual, domestic installations. Computer smulations indicate that under a variety of climatologic conditions, groundwater heat pumps use less energy than conventional heating and cooling equipment. Life-cycle cost comparisons with conventional equipment depend on alternative system choices and well cost options included in the groundwater heat pump system.

  10. Cooling device of superconducting coils

    International Nuclear Information System (INIS)

    Duthil, R.; Lottin, J.C.

    1985-01-01

    This device is rotating around an horizontal axis. The superconducting coils are contained in a cryogenic enclosure feeded in liquid helium forced circulation. They are related to an electric generator by electric mains each of them comprising a gas exchanger, and an exchanger-evaporator set between the cryogenic device and those exchangers. The exchanger-evaporator is aimed at dissipating the heat arriving by conductors connected to the superconducting coils. According to the invention, the invention includes an annular canalization with horizontal axis in which the connection conductors bathe in liquid helium [fr

  11. Artificial neural networks and adaptive neuro-fuzzy assessments for ground-coupled heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23279 Elazig (Turkey); Sengur, Abdulkadir [Department of Electronic and Computer Science, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey)

    2008-07-01

    This article present a comparison of artificial neural network (ANN) and adaptive neuro-fuzzy inference systems (ANFIS) applied for modelling a ground-coupled heat pump system (GCHP). The aim of this study is predicting system performance related to ground and air (condenser inlet and outlet) temperatures by using desired models. Performance forecasting is the precondition for the optimal design and energy-saving operation of air-conditioning systems. So obtained models will help the system designer to realize this precondition. The most suitable algorithm and neuron number in the hidden layer are found as Levenberg-Marquardt (LM) with seven neurons for ANN model whereas the most suitable membership function and number of membership functions are found as Gauss and two, respectively, for ANFIS model. The root-mean squared (RMS) value and the coefficient of variation in percent (cov) value are 0.0047 and 0.1363, respectively. The absolute fraction of variance (R{sup 2}) is 0.9999 which can be considered as very promising. This paper shows the appropriateness of ANFIS for the quantitative modeling of GCHP systems. (author)

  12. Large coil test facility conceptual design report

    International Nuclear Information System (INIS)

    Nelms, L.W.; Thompson, P.B.; Mann, T.L.

    1978-02-01

    In the development of a superconducting toroidal field (TF) magnet for The Next Step (TNS) tokamak reactor, several different TF coils, about half TNS size, will be built and tested to permit selection of a design and fabrication procedure for full-scale TNS coils. A conceptual design has been completed for a facility to test D-shaped TF coils, 2.5 x 3.5-m bore, operating at 4-6 K, cooled either by boiling helium or by forced-flow supercritical helium. Up to six coils can be accommodated in a toroidal array housed in a single vacuum tank. The principal components and systems in the facility are an 11-m vacuum tank, a test stand providing structural support and service connections for the coils, a liquid nitrogen system, a system providing helium both as saturated liquid and at supercritical pressure, coils to produce a pulsed vertical field at any selected test coil position, coil power supplies, process instrumentation and control, coil diagnostics, and a data acquisition and handling system. The test stand structure is composed of a central bucking post, a base structure, and two horizontal torque rings. The coils are bolted to the bucking post, which transmits all gravity loads to the base structure. The torque ring structure, consisting of beams between adjacent coils, acts with the bucking structure to react all the magnetic loads that occur when the coils are energized. Liquid helium is used to cool the test stand structure to 5 K to minimize heat conduction to the coils. Liquid nitrogen is used to precool gaseous helium during system cooldown and to provide thermal radiation shielding

  13. Numerical study on the impact of ground heating and ambient wind speed on flow fields in street canyons

    Science.gov (United States)

    Li, Lei; Yang, Lin; Zhang, Li-Jie; Jiang, Yin

    2012-11-01

    The impact of ground heating on flow fields in street canyons under different ambient wind speed conditions was studied based on numerical methods. A series of numerical tests were performed, and three factors including height-to-width (H/W) ratio, ambient wind speed and ground heating intensity were taken into account. Three types of street canyon with H/W ratios of 0.5, 1.0 and 2.0, respectively, were used in the simulation and seven speed values ranging from 0.0 to 3.0 m s-1 were set for the ambient wind speed. The ground heating intensity, which was defined as the difference between the ground temperature and air temperature, ranged from 10 to 40 K with an increase of 10 K in the tests. The results showed that under calm conditions, ground heating could induce circulation with a wind speed of around 1.0 m s-1, which is enough to disperse pollutants in a street canyon. It was also found that an ambient wind speed threshold may exist for street canyons with a fixed H/W ratio. When ambient wind speed was lower than the threshold identified in this study, the impact of the thermal effect on the flow field was obvious, and there existed a multi-vortex flow pattern in the street canyon. When the ambient wind speed was higher than the threshold, the circulation pattern was basically determined by dynamic effects. The tests on the impact of heating intensity showed that a higher ground heating intensity could strengthen the vortical flow within the street canyon, which would help improve pollutant diffusion capability in street canyons.

  14. Primary heat transport pump trip by ground fault (deterioration of insulation in the cable quick disconnect)

    International Nuclear Information System (INIS)

    Chun, C.-Y.

    1991-01-01

    At 08:29 Sept. 1, 1988, Wolsong unit 1 was operating at 100% full power when a primary heat transport pump was suddenly tripped by breaker trip due to ground fault in the power distribution connector assembly. Soon after the pump trip, the reactor was shut down automatically on low heat transport flow. Operators tried to restart the pump twice but failed. A field operator reported to the shift supervisor that he found an electrical spark and smoke at the vicinity of the pump when the pump started to run. Inspection showed that a power distribution connector assembly for making fast and easy power connections to the PHT pump motor, 3312-PM2, was damaged severely by thermal shock. Particularly, broken parts of the insulating plug flew away across the boiler room and dropped to the floor. Direct causes of the failure were bad contact and deterioration of integrity along the creep paths between the insulating plug and the connector housing. The failed connector assembly had been used for more than 7 years. Its status had been checked infrequently during the in-service period. The standard torque value was not applied to the installation of connectors. Therefore, we concluded that long term inservice in combinations of application of improper torque value induced failure of insulation. This paper describes the scenarios, causes of the event and corrective actions to prevent recurrence of this event. (author)

  15. Primary heat transport pump trip by ground fault (deterioration of insulation in the cable quick disconnect)

    Energy Technology Data Exchange (ETDEWEB)

    Chun, C -Y [Wolsong Nuclear Power Plant, Korea Electric Power Corporation, Wolsong (Korea, Republic of)

    1991-04-01

    At 08:29 Sept. 1, 1988, Wolsong unit 1 was operating at 100% full power when a primary heat transport pump was suddenly tripped by breaker trip due to ground fault in the power distribution connector assembly. Soon after the pump trip, the reactor was shut down automatically on low heat transport flow. Operators tried to restart the pump twice but failed. A field operator reported to the shift supervisor that he found an electrical spark and smoke at the vicinity of the pump when the pump started to run. Inspection showed that a power distribution connector assembly for making fast and easy power connections to the PHT pump motor, 3312-PM2, was damaged severely by thermal shock. Particularly, broken parts of the insulating plug flew away across the boiler room and dropped to the floor. Direct causes of the failure were bad contact and deterioration of integrity along the creep paths between the insulating plug and the connector housing. The failed connector assembly had been used for more than 7 years. Its status had been checked infrequently during the in-service period. The standard torque value was not applied to the installation of connectors. Therefore, we concluded that long term inservice in combinations of application of improper torque value induced failure of insulation. This paper describes the scenarios, causes of the event and corrective actions to prevent recurrence of this event. (author)

  16. Geothermal(Ground-Source)Heat Pumps: Market Status, Barriers to Adoption, and Actions to Overcome Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Patrick [ORNL

    2008-12-01

    More effective stewardship of our resources contributes to the security, environmental sustainability, and economic well-being of the nation. Buildings present one of the best opportunities to economically reduce energy consumption and limit greenhouse gas emissions. Geothermal heat pumps (GHPs), sometimes called ground-source heat pumps, have been proven capable of producing large reductions in energy use and peak demand in buildings. However, GHPs have received little attention at the policy level as an important component of a national strategy. Have policymakers mistakenly overlooked GHPs, or are GHPs simply unable to make a major contribution to the national goals for various reasons? This brief study was undertaken at DOE's request to address this conundrum. The scope of the study includes determining the status of global GHP markets and the status of the GHP industry and technology in the United States, assembling previous estimates of GHP energy savings potential, identifying key barriers to application of GHPs, and identifying actions that could accelerate market adoption of GHPs. The findings are documented in this report along with conclusions and recommendations.

  17. IEA HPP Annex 29 - ground-source heat pumps overcoming technical and market barriers. Status report Norway

    International Nuclear Information System (INIS)

    Stene, Joern

    2004-12-01

    Norway is a member of Annex 29, 'Ground-Source Heat Pump Systems Overcoming Technical and Market Barriers' (2004-2006), organized under the umbrella of the International Energy Agency (IEA) and the IEA Heat Pump Programme (HPP). The 7 participating countries are Austria (Operating Agent), Canada, Japan, Norway, Spain, Sweden and the USA. The Norwegian participation is financed by ENOVA SF, and SINTEF Energy Research is responsible for planning and carrying out the Norwegian activities. This report provides a status for ground-source heat pump (GSHP) systems in Norway with regard to state-of-the-art technology, installation examples, geological data, costs and market opportunities. A Norwegian Internet home page for ground-source heat pump systems (www.energy.sintef.no/prosjekt/Annex29) is also presented. GSHP systems in Norway are classified as direct systems (groundwater and soil/ground) and indirect closed-loop systems (vertical-rock and horizontal-soil/ground). The vast majority of the installations are indirect closed-loop systems utilizing vertical boreholes in rock as a heat source, heat sink and thermal energy storage. GSHP systems are relatively capital intensive installations, but they achieve high energy efficiency due to the relatively high and stable heat source temperature and the fact that a considerable share of the cooling demand in non-residential buildings can be covered by means of free cooling. In order to obtain energy efficient and reliable GSHP installations, it is important to implement a total quality concept where focus is on quality and system integration during all stages of the project. A life cycle analysis (LCA) will be an important tool in such a concept, since both the investment costs as well as the lifetime operational and maintenance costs are included (author) (ml) Litt usikker pae tag 620- ikke en vanlig sintef rapportkode

  18. Optimization of operating parameters of ground source heat pump system for space heating and cooling by Taguchi method and utility concept

    International Nuclear Information System (INIS)

    Sivasakthivel, T.; Murugesan, K.; Thomas, H.R.

    2014-01-01

    Highlights: • Ground Source Heat Pump (GSHP) technology is suitable for both heating and cooling. • Important parameters that affect the GSHP performance has been listed. • Parameters of GSHP system has been optimized for heating and cooling mode. • Taguchi technique and utility concept are developed for GSHP optimization. - Abstract: Use of ground source energy for space heating applications through Ground Source Heat pump (GSHP) has been established as an efficient thermodynamic process. The electricity input to the GSHP can be reduced by increasing the COP of the system. However, the COP of a GSHP system will be different for heating and cooling mode operations. Hence in order to reduce the electricity input to the GSHP, an optimum value of COP has to be determined when GSHP is operated in both heating and cooling modes. In the present research, a methodology is proposed to optimize the operating parameters of a GSHP system which will operate on both heating and cooling modes. Condenser inlet temperature, condenser outlet temperature, dryness fraction at evaporator inlet and evaporator outlet temperature are considered as the influencing parameters of the heat pump. Optimization of these parameters for only heating or only cooling mode operation is achieved by employing Taguchi method for three level variations of the above parameters using an L 9 (3 4 ) orthogonal array. Higher the better concept has been used to get a higher COP. A computer program in FORTAN has been developed to carry out the computations and the results have been analyzed for the optimum conditions using Signal-to-Noise (SN) ratio and Analysis Of Variance (ANOVA) method. Based on this analysis, the maximum COP for only heating and only cooling operation are obtained as 4.25 and 3.32 respectively. By making use of the utility concept both the higher values of COP obtained for heating and cooling modes are optimized to get a single optimum COP for heating and cooling modes. A single

  19. Passive Residential Houses with the Accumulation Properties of Ground as a Heat Storage Medium

    Science.gov (United States)

    Ochab, Piotr; Kokoszka, Wanda; Kogut, Janusz; Skrzypczak, Izabela; Szyszka, Jerzy; Starakiewicz, Aleksander

    2017-12-01

    Solar radiation is the primary source of life energy on Earth. The irradiance of the upper atmosphere is about 1360 W/m2, and it is estimated that about 1000 W/m2 reaches the ground. Long-term storage of heat energy is related to the use of a suitable thermal energy carrier. It may be either artificial or natural water tank, or artificial gravel-water tank, or aquifer or soil. It is justified to store the generated energy in large heating systems due to the nature of solar thermal energy. Typically, in such a solution storage space is a large solar collector farm. The reason for this is the proportionally small unit profits, which only in the case of large number of units provides sufficient energy that can be accumulated. It should be noted that Poland, a country located in a temperate and less harsh climate such as Scandinavia and Canada, has a relatively high potential for solar revenue. In the last decade, it has caused mainly small and individual heating installations. However, much of the municipal and industrial economy continues to rely on energy from non-renewable resources. This is due not only to the lack of a high-efficiency alternative to non-renewable energy resources, but also to the thermal state of buildings throughout the country, where old buildings require thermomodernization. This has the effect of both polluting the environment and the occurrence of smog, as well as pollutants in water and soil. This directly affects the occurrence of civilization diseases and other societal health problems. Therefore, the surplus of thermal clean energy that occurs during the spring and summer period should not only be used on a regular basis, but also stored for later winter use. The paper presents the concept of housing estate, which consists of 32 twin housing units. The solid character of buildings consistently refers to passive construction, and the materials meet the requirements for the passive buildings.

  20. Switching transients in a superconducting coil

    International Nuclear Information System (INIS)

    Owen, E.W.; Shimer, D.W.

    1983-01-01

    A study is made of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to performance tests on the MFTF Yin-yang coils. It is found that the breaker opening time is the critical factor in determining the size and shape of the transient. Instantaneous opening of the breaker causes a lightly damped transient with large amplitude voltages to ground. Increasing the opening time causes the transient to become a monopulse of decreasing amplitude. The voltages at the external terminals are determined by the parameters of the external circuit. For fast opening times the frequency depends on the dump resistor inductance, the circuit capacitance, and the amplitude on the coil current. For slower openings the dump resistor inductance and the current determine the amplitude of the voltage to ground at the terminals. Voltages to ground are less in the interior of the coil, where transients related to the parameters of the coil itself are observed

  1. Feasibility study on novel hybrid ground coupled heat pump system with nocturnal cooling radiator for cooling load dominated buildings

    International Nuclear Information System (INIS)

    Man, Yi; Yang, Hongxing; Spitler, Jeffrey D.; Fang, Zhaohong

    2011-01-01

    Highlights: → Propose a novel HGCHP system with NCR works as supplemental heat rejecter. → Establish the analytical model and computer program of NCR and novel HGCHP system to simulate their operation performance. → Design the novel HGCHP system for a sample building located in Hong Kong. → It is found to be feasible to use NCR serves as supplemental heat rejecter of the novel HGCHP system. → The novel HGCHP system provides a new valuable choice for air conditioning in cooling load dominated buildings. -- Abstract: When the ground coupled heat pump (GCHP) system is utilized for air conditioning in cooling load dominated buildings, the heat rejected into ground will accumulate around the ground heat exchangers (GHE) and results in system performance degradation. A novel hybrid ground coupled heat pump (HGCHP) system with nocturnal cooling radiator (NCR) works as supplemental heat rejecter is proposed in this paper to resolve this problem. The practical analytical model of NCR and novel HGCHP system are established. The computer program based on established model is developed to simulate the system operation performance. The novel HGCHP system is designed and simulated for a sample building located in Hong Kong, and a simple life cycle cost comparisons are carried out between this system and conventional GCHP system. The results indicate that it is feasible to use NCR serves as supplemental heat rejecter of the novel HGCHP system for cooling load dominated buildings even those located in humid subtropical climate areas. This novel HGCHP system provides a new valuable choice for air conditioning in cooling load dominated buildings, and it is especially suitable for buildings with limited surface land areas.

  2. Comparison between design and actual energy performance of a HVAC-ground coupled heat pump system in cooling and heating operation

    Energy Technology Data Exchange (ETDEWEB)

    Magraner, T.; Quilis, S. [Energesis Ingenieria S.L., Ciudad Politecnica de la Innovacion, Camino de Vera s/n, 46022 Valencia (Spain); Montero, A. [Instituto de Ingenieria Energetica, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Urchueguia, J.F. [Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2010-09-15

    This work compares the experimental results obtained for the energy performance study of a ground coupled heat pump system with the design values predicted by means of standard methodology. The system energy performance of a monitored ground coupled heat pump system is calculated using the instantaneous measurements of temperature, flow and power consumption and these values are compared with the numerical predictions. These predictions are performed with the TRNSYS software tool following standard procedures taking the experimental thermal loads as input values. The main result of this work is that simulation results solely based on nominal heat pump capacities and performances overestimate the measured overall energy performance by a percentage between 15% and 20%. A sensitivity analysis of the simulation results to changes in percentage of its input parameters showed that the heat pump nominal coefficient of performance is the parameter that mostly affects the energy performance predictions. This analysis supports the idea that the discrepancies between experimental results and simulation outputs for this ground coupled system are mainly due to heat pump performance degradation for being used at partial load. An estimation of the impact of this effect in energy performance predictions reduces the discrepancies to values around 5%. (author)

  3. Coil supporting device for a nuclear fusion device

    International Nuclear Information System (INIS)

    Kuno, Kazuo.

    1976-01-01

    Object: To reduce a thermal stress of a coil such as a magnetic limiter to minimize stress acting on a protective tube of the coil. Structure: A coil within a protective tube has its outer periphery surrounded and supported by a heat-resisting material such as ceramic at more than two positions suitably spaced lengthwise of a coil conductor, and heat insulating members are interposed between both sides of the coil and the protective tube so that it may be retained with respect to the width of the coil. Further, a heat-resisting resilient member is inserted in a clearance between an outer circumference and an inner circumference of the coil to allow a radial displacement of the coil. As a result, elongation of the coil due to thermal expansion may be escaped at the aforesaid two supports to reduce thermal stress of the coil and protective tube to support the coil within the protective tube in positively heat-resisting and insulating manner. (Kamimura, M.)

  4. Superconductive magnet having shim coils and quench protection circuits

    International Nuclear Information System (INIS)

    Schwall, R.E.

    1987-01-01

    A superconductive magnet is described comprising: a first persistent current loop comprising a first superconductor and a main coil connected to the first superconductor, the main coil being operative in response to superconduction therein to generate a primary magnetic field; a second persistent current loop comprising a second superconductor and a shim coil connected thereto, the shim coil being operative in response to superconduction therein to generate a corrective field for correcting aberrations in a predetermined gradient in the primary magnetic field, the shim coil having fewer turns than the main coil and being inductively coupled therewith whereby small changes in the current in the main coil cause much greater changes in the current in the shim coil. The magnet is characterized by an improvement which consists of: a first heater connected across the second persistent loop in parallel with the shim coil, the first heater being normally inoperative to carry current while the shim coil and the second superconductor are superconducting, the first heater being operative in response to current therein to heat the shim coil to a resistive state; and protective circuit means comprising a second heater connected to the main coil for carrying current from the main coil upon quenching of the main coil, the second heater being disposed in thermal contact with the second superconductor to heat the second superconductor to a resistive state in response to the current from the main coil to thereby divert current in the second persistent loop through the second heater causing it to heat the shim coil to a resistive state and resistively dissipate energy therein

  5. Guide to the Revised Ground-Water Flow and Heat Transport Simulator: HYDROTHERM - Version 3

    Science.gov (United States)

    Kipp, Kenneth L.; Hsieh, Paul A.; Charlton, Scott R.

    2008-01-01

    The HYDROTHERM computer program simulates multi-phase ground-water flow and associated thermal energy transport in three dimensions. It can handle high fluid pressures, up to 1 ? 109 pascals (104 atmospheres), and high temperatures, up to 1,200 degrees Celsius. This report documents the release of Version 3, which includes various additions, modifications, and corrections that have been made to the original simulator. Primary changes to the simulator include: (1) the ability to simulate unconfined ground-water flow, (2) a precipitation-recharge boundary condition, (3) a seepage-surface boundary condition at the land surface, (4) the removal of the limitation that a specified-pressure boundary also have a specified temperature, (5) a new iterative solver for the linear equations based on a generalized minimum-residual method, (6) the ability to use time- or depth-dependent functions for permeability, (7) the conversion of the program code to Fortran 90 to employ dynamic allocation of arrays, and (8) the incorporation of a graphical user interface (GUI) for input and output. The graphical user interface has been developed for defining a simulation, running the HYDROTHERM simulator interactively, and displaying the results. The combination of the graphical user interface and the HYDROTHERM simulator forms the HYDROTHERM INTERACTIVE (HTI) program. HTI can be used for two-dimensional simulations only. New features in Version 3 of the HYDROTHERM simulator have been verified using four test problems. Three problems come from the published literature and one problem was simulated by another partially saturated flow and thermal transport simulator. The test problems include: transient partially saturated vertical infiltration, transient one-dimensional horizontal infiltration, two-dimensional steady-state drainage with a seepage surface, and two-dimensional drainage with coupled heat transport. An example application to a hypothetical stratovolcano system with unconfined

  6. An experimental study on the negative effects of downwards flow of the melted frost over a multi-circuit outdoor coil in an air source heat pump during reverse cycle defrosting

    International Nuclear Information System (INIS)

    Song, Mengjie; Pan, Dongmei; Li, Ning; Deng, Shiming

    2015-01-01

    Highlights: • A special experimental rig was built and its details are reported. • The negative effects of downwards flowing of the melted frost were shown. • Defrosting duration was shortened after installing water collecting trays. • Temperature of melted frost decreased after installing trays. - Abstract: When the surface temperature of the outdoor coil in an air source heat pump (ASHP) unit is lower than both freezing point of water and the air dew point, frost can be formed and accumulated over outdoor coil surface. Frosting affects the energy efficiency, and periodic defrosting therefore is necessary. Reverse cycle defrosting is currently the most widely used defrosting method. A previous related study has indicated that during reverse cycle defrosting, downwards flow of the melted frost over a multi-circuit outdoor coil could affect the defrosting performance, without however giving detailed quantitative analysis of the effects. Therefore an experimental study on the effects has been carried out and a quantitative analysis conducted using the experimental data. In this paper, the detailed description of an experimental ASHP unit which was specifically built up is firstly reported. This is followed by presenting experimental results. Result analysis and conclusions are finally given

  7. Testing electrical insulation of LCT coils and instrumentation

    International Nuclear Information System (INIS)

    Luton, J.N.; Ulbricht, A.R.; Ellis, J.F.; Shen, S.S.; Wilson, C.T.; Okuno, K.; Siewerdt, L.O.; Zahn, G.R.; Zichy, J.A.

    1986-09-01

    Three of the superconducting test coils in the Large Coil Task (LCT) use conductors cooled internally by forced flow of helium. In the other three coils, the conductors are cooled externally by a bath of helium. The coils and facility are designed for rapid discharges (dumps) at voltages up to 2.5 kV, depending on coil design. Many coil sensors are connected electrically to the conductors. These sensor leads and signal conditioning equipment also experience high voltage. High-potential tests of ground insulation were performed on all components of the International Fusion Superconducting Magnet Test Facility (IFSMTF). Coil insulation was also tested by ring-down tests that produced voltage distributions within the coils like those occurring during rapid discharge. Methods were developed to localize problem areas and to eliminate them. The effect on breakdown voltage near the Paschen minimum of magnetic fields up to 2 T was investigated

  8. A two-region simulation model of vertical U-tube ground heat exchanger and its experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Weibo; Liu, Guangyuan [School of Energy and Power Engineering, Yangzhou University, Yangzhou City (China); Shi, Mingheng; Chen, Zhenqian [School of Energy and Environment, Southeast University, Nanjing City (China)

    2009-10-15

    Heat transfer around vertical ground heat exchanger (GHE) is a common problem for the design and simulation of ground coupled heat pump (GCHP). In this paper, an updated two-region vertical U-tube GHE analytical model, which is fit for system dynamic simulation of GCHP, is proposed and developed. It divides the heat transfer region of GHE into two parts at the boundary of borehole wall, and the two regions are coupled by the temperature of borehole wall. Both steady and transient heat transfer method are used to analyze the heat transfer process inside and outside borehole, respectively. The transient borehole wall temperature is calculated for the soil region outside borehole by use of a variable heat flux cylindrical source model. As for the region inside borehole, considering the variation of fluid temperature along the borehole length and the heat interference between two adjacent legs of U-tube, a quasi-three dimensional steady-state heat transfer analytical model for the borehole is developed based on the element energy conservation. The implement process of the model used in the dynamic simulation of GCHPs is illuminated in detail and the application calculation example for it is also presented. The experimental validation on the model is performed in a solar-geothermal multifunctional heat pump experiment system with two vertical boreholes and each with a 30 m vertical 1 1/4 in nominal diameter HDPE single U-tube GHE, the results indicate that the calculated fluid outlet temperatures of GHE by the model are agreed well with the corresponding test data and the guess relative error is less than 6%. (author)

  9. Satellite and ground-based sensors for the Urban Heat Island analysis in the city of Rome

    DEFF Research Database (Denmark)

    Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo

    2010-01-01

    In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...... by the authors; licensee MDPI, Basel, Switzerland. Keyword: Thermal pollution,Summer months,Advanced-along track scanning radiometers,Urban heat island,Remote sensing,Canopy layer,Atmospheric temperature,Ground based sensors,Weather information services,Satellite remote sensing,Infra-red sensor,Weather stations...

  10. Seasonal coefficient of performance for ground source heat pump and groundwater one in Białystok

    Science.gov (United States)

    Gajewski, Andrzej

    2017-11-01

    European Economic Area (EEA) states declare to contain greenhouse gases emissions at 20% by 2020, whereas European Union (EU) does 40% before 2030, which result in encouragement to apply low-carbon technologies. Coefficient of Performance (COP) and Seasonal Coefficient of Performance (SCOPnet) are obtained using temperature measurement done by The Institute of Meteorology and Water Management - National Research Institute (IMGW-PIB) at the weather station in Bialystok for ten-year period. The first variant is ground source heat pump (GSHP) and the second one is groundwater source heat pump (WSHP) which can be equipped with separating heat exchanger (SHE) optionally. In both cases heat is generated for heating system only. Ground temperature is determined from Baggs (1983) formula using Oleśkowicz-Popiel et. al. (2002) adaptation to Polish climate and substituting the local constants achieved by Biernacka (2010). Water temperature in a groundwater basin is obtained from Kowalski (2007) equation. Estimation is done in each hour of heating season. All COP values are higher than 3.5 required by EU (2013). SCOPnet are as follows: 6.12, 5.86, 5.03 for WSHP, WSHP+SHE, GSHP respectively. Insomuch as WSHP needs only two boreholes it is recommended to the areas beneath ones a groundwater basin is located.

  11. Seasonal coefficient of performance for ground source heat pump and groundwater one in Białystok

    Directory of Open Access Journals (Sweden)

    Gajewski Andrzej

    2017-01-01

    Full Text Available European Economic Area (EEA states declare to contain greenhouse gases emissions at 20% by 2020, whereas European Union (EU does 40% before 2030, which result in encouragement to apply low-carbon technologies. Coefficient of Performance (COP and Seasonal Coefficient of Performance (SCOPnet are obtained using temperature measurement done by The Institute of Meteorology and Water Management – National Research Institute (IMGW-PIB at the weather station in Bialystok for ten-year period. The first variant is ground source heat pump (GSHP and the second one is groundwater source heat pump (WSHP which can be equipped with separating heat exchanger (SHE optionally. In both cases heat is generated for heating system only. Ground temperature is determined from Baggs (1983 formula using Oleśkowicz-Popiel et. al. (2002 adaptation to Polish climate and substituting the local constants achieved by Biernacka (2010. Water temperature in a groundwater basin is obtained from Kowalski (2007 equation. Estimation is done in each hour of heating season. All COP values are higher than 3.5 required by EU (2013. SCOPnet are as follows: 6.12, 5.86, 5.03 for WSHP, WSHP+SHE, GSHP respectively. Insomuch as WSHP needs only two boreholes it is recommended to the areas beneath ones a groundwater basin is located.

  12. Coil assembly for use with an electric motor

    NARCIS (Netherlands)

    2008-01-01

    Coil assemblies ( 2 ) of electric motors ( 1 ) produce heat that can be a disadvantage when needing the electric motor ( 1 ) for high precision positioning applications. To reduce the negative impact of the heat, the coils ( 26 a , 26 b , 26 c) are arranged in an internally cooled housing ( 21 ).

  13. Water cooling coil

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, S; Ito, Y; Kazawa, Y

    1975-02-05

    Object: To provide a water cooling coil in a toroidal nuclear fusion device, in which coil is formed into a small-size in section so as not to increase dimensions, weight or the like of machineries including the coil. Structure: A conductor arranged as an outermost layer of a multiple-wind water cooling coil comprises a hollow conductor, which is directly cooled by fluid, and as a consequence, a solid conductor disposed interiorly thereof is cooled indirectly.

  14. Simulation of the thermal performance of a hybrid solar-assisted ground-source heat pump system in a school building

    Science.gov (United States)

    Androulakis, N. D.; Armen, K. G.; Bozis, D. A.; Papakostas, K. T.

    2018-04-01

    A hybrid solar-assisted ground-source heat pump (SAGSHP) system was designed, in the frame of an energy upgrade study, to serve as a heating system in a school building in Greece. The main scope of this study was to examine techniques to reduce the capacity of the heating equipment and to keep the primary energy consumption low. Simulations of the thermal performance of both the building and of five different heating system configurations were performed by using the TRNSYS software. The results are presented in this work and show that the hybrid SAGSHP system displays the lower primary energy consumption among the systems examined. A conventional ground-source heat pump system has the same primary energy consumption, while the heat pump's capacity is double and the ground heat exchanger 2.5 times longer. This work also highlights the contribution of simulation tools to the design of complex heating systems with renewable energy sources.

  15. Ohmic Heating System for the TFTR Tokamak

    International Nuclear Information System (INIS)

    Petree, F.; Cassel, R.

    1977-01-01

    The TFTR Ohmic Heating (OH) System will apply 140,000 volt impulses upon the OH coils to start the plasma. In order to reduce the voltage stress to ground on the OH coils to 12 kV without changing the magnetic field induced by the OH system in the plasma, six d-c current interrupters will be applied to six entry points in the OH coil system. And in order to impart a nearly rectangular shape to these impulses, the voltage determining elements will be nonlinear resistances placed in parallel with the interrupters. These nonlinear resistors, made of semiconducting material, are not normally used in repetitive or continuous duty, and their proper functioning is crucial to the reliable operation of the system. The system described herein, is being revised owing to the impact of revisions to the Toroidal Field Coil System, and to refinements to the OH System design

  16. A study of the Oklahoma City urban heat island using ground measurements and remote sensing

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M. J. (Michael J.); Ivey, A. (Austin); McPherson, T. N. (Timothy N.); Boswell, D. (David); Pardyjak, E. R. (Eric R.)

    2004-01-01

    Measurements of temperature and position were collected during the night from an instrumented van on routes through Oklahoma City and the rural outskirts. The measurements were taken as part of the Joint URBAN 2003 Tracer Field Experiment conducted in Oklahoma City from June 29, 2003 to July 30, 2003 (Allwine et al., 2004). The instrumented van was driven over four primary routes that included legs from the downtown core to four different 'rural' areas. Each route went through residential areas and most often went by a line of permanently fixed temperature probes (Allwine et al., 2004) for cross-checking purposes. Each route took from 20 to 40 minutes to complete. Based on seven nights of data, initial analyses indicate that there was a temperature difference of 0.5-6.5 C between the urban core and nearby 'rural' areas. Analyses also suggest that there were significant fine scale temperature differences over distances of tens of meters within the city and in the nearby rural areas. The temperature measurements that were collected are intended to supplement the meteorological measurements taken during the Joint URBAN 2003 Field Experiment, to assess the importance of the urban heat island phenomenon in Oklahoma City, and to test new urban canopy parameterizations that have been developed for regional scale meteorological codes (e.g., Chin et al., 2000; Holt and Shi, 2004). In addition to the ground measurements, skin temperature measurements were also analyzed from remotely sensed images taken from the Earth Observing System's Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). A surface kinetic temperature thermal infrared image captured by the ASTER of the Oklahoma City area on July 21, 2001 was analyzed within ESRI's ArcGIS 8.3 to correlate variations in temperature with land use type. Analysis of this imagery suggests distinct variations in temperature across different land use categories. Through the use of

  17. NCSX Trim Coil Design

    International Nuclear Information System (INIS)

    Kalish, M.; Brooks, A.; Rushinski, J.; Upcavage, R.

    2009-01-01

    The National Compact Stellarator Experiment (NCSX) was being constructed at the Princeton Plasma Physics Laboratory in partnership with Oak Ridge National Laboratory before work was stopped in 2008. The objective of this experiment was to develop the stellarator concept and evaluate it's potential as a model for future fusion power plants. Stellarator design requires very precisely positioned Modular Coils of complex shape to form 3D plasmas. In the design of NCSX, Trim Coils were required to compensate for both the positioning of the coils during assembly and the fabrication tolerances of the Modular Coils. Use of the Trim Coils allowed for larger tolerances increasing ease of assembly and decreasing overall cost. A set of Trim coils was developed to suppress the toroidal flux in island regions due to misalignment, magnetic materials, and eddy currents. The requirement imposed upon the design forced the toroidal flux in island regions below 10% of the total toroidal flux in the plasma. An analysis was first performed to evaluate candidate Trim Coil configurations iterating both the size, number, and position of the coils. The design was optimized considering both performance and cost while staying within the tight restraints presented by the space limited geometry. The final design of the Trim Coils incorporated a 48 Coil top bottom symmetric set. Fabrication costs were minimized by having only two coil types and using a planar conventional design with off the shelf commercial conductor. The Trim Coil design incorporated supports made from simple structural shapes assembled together in a way which allowed for adjustment as well as accommodation for the tolerance build up on the mating surfaces. This paper will summarize the analysis that led to the optimization of the Trim Coils set, the trim coil mechanical design, thermal and stress analysis, and the design of the supporting Trim Coil structure

  18. Modeling a ground-coupled heat pump system by a support vector machine

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23279 Elazig (Turkey); Sengur, Abdulkadir [Department of Electronic and Computer Science, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey)

    2008-08-15

    This paper reports on a modeling study of ground coupled heat pump (GCHP) system performance (COP) by using a support vector machine (SVM) method. A GCHP system is a multi-variable system that is hard to model by conventional methods. As regards the SVM, it has a superior capability for generalization, and this capability is independent of the dimensionality of the input data. In this study, a SVM based method was intended to adopt GCHP system for efficient modeling. The Lin-kernel SVM method was quite efficient in modeling purposes and did not require a pre-knowledge about the system. The performance of the proposed methodology was evaluated by using several statistical validation parameters. It is found that the root-mean squared (RMS) value is 0.002722, the coefficient of multiple determinations (R{sup 2}) value is 0.999999, coefficient of variation (cov) value is 0.077295, and mean error function (MEF) value is 0.507437 for the proposed Lin-kernel SVM method. The optimum parameters of the SVM method were determined by using a greedy search algorithm. This search algorithm was effective for obtaining the optimum parameters. The simulation results show that the SVM is a good method for prediction of the COP of the GCHP system. The computation of SVM model is faster compared with other machine learning techniques (artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS)); because there are fewer free parameters and only support vectors (only a fraction of all data) are used in the generalization process. (author)

  19. Modeling and Experimental Studies for the Thermal Performance of a Ground Heat Storage System Integrated with a Greenhouse

    International Nuclear Information System (INIS)

    Kooli, Sami; Lazaar, Mariem; Hazami, Majdi; Farhat, Abdelhamid; Belghith, Ali

    2009-01-01

    A thermal model has been developed to investigate the potential of using the stored thermal energy of the ground for greenhouse heating and cooling with the help of a ground heat storage system (GHSS) integrated with the greenhouse located in the premises of CRTEn, Tunis, Tunisia. Experiments were conducted extensively throughout the years 2006-2007, and the developed model was validated against several consecutive arbitrary days experiments. The predicted and measured values of the greenhouse air temperatures and humidities that were verified, in terms of root mean square deviation and correlation coefficient, exhibited fair agreement. The results of this study showed that the GHS system kept the inside air temperature 1-3 degree higher than that of outside air at nighttime. The main reason for this low efficiency is due to the weak heat transfer area of the water-air heat exchanger. The simulation results indicate that the GHSS does not yield any significant effect for cooling greenhouses during sunny daytime. The GHSS fulfils its full potential for a heat transfer area of 150 m 2 . With this area, there occurs 4-6 degree rise of temperature in greenhouse as compared to the temperatures without GHSS and respectively 5-7.5 degree rise in greenhouse as compared to outside air

  20. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  1. A modified Gaussian model for the thermal plume from a ground-based heat source in a cross-wind

    International Nuclear Information System (INIS)

    Selander, W.N.; Barry, P.J.; Robertson, E.

    1990-06-01

    An array of propane burners operating at ground level in a cross-wind was used as a heat source to establish a blown-over thermal plume. A three-dimensional array of thermocouples was used to continuously measure the plume temperature downwind from the source. The resulting data were used to correlate the parameters of a modified Gaussian model for plume rise and dispersion with source strength, wind speed, and atmospheric dispersion parameters

  2. Ground-Source Heat Pumps. Overview of Market Status, Barriers to Adoption, and Options for Overcoming Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Goetzler, William [Navigant Consulting, Inc., Chicago, IL (United States); Zogg, Robert [Navigant Consulting, Inc., Chicago, IL (United States); Lisle, Heather [Navigant Consulting, Inc., Chicago, IL (United States); Burgos, Javier [Navigant Consulting, Inc., Chicago, IL (United States)

    2009-02-03

    February 2009 final report submitted to DOE by Navigant Consulting, Inc. This report summarizes the status of ground-source heat pump (GSHP) technology and market penetration globally, estimates the energy saving potential of GSHPs in the U.S., identifies key market barriers that are inhibiting wider market adoption of GSHPs, and recommends initiatives that can be implemented or facilitated by the DOE to accelerate market adoption.

  3. Performance of the Conduction-Cooled LDX Levitation Coil

    Science.gov (United States)

    Michael, P. C.; Schultz, J. H.; Smith, B. A.; Titus, P. H.; Radovinsky, A.; Zhukovsky, A.; Hwang, K. P.; Naumovich, G. J.; Camille, R. J.

    2004-06-01

    The Levitated Dipole Experiment (LDX) was developed to study plasma confinement in a dipole magnetic field. Plasma is confined in the magnetic field of a 680-kg Nb3Sn Floating Coil (F-coil) that is electromagnetically supported at the center of a 5-m diameter by 3-m tall vacuum chamber. The Levitation Coil (L-coil) is a 2800-turn, double pancake winding that supports the weight of the F-coil and controls its vertical position within the vacuum chamber. The use of high-temperature superconductor (HTS) Bi-2223 for the L-coil minimizes the electrical and cooling power needed for levitation. The L-coil winding pack and support plate are suspended within the L-coil cryostat and cooled by conduction to a single-stage cryocooler rated for 25-W heat load at approximately 20 K. The coil current leads consist of conduction-cooled copper running from room temperature to 80 K and a pair of commercially-available, 150-A HTS leads. An automatically filled liquid-nitrogen reservoir provides cooling for the coil's radiation shield and for the leads' 80-K heat stations. This paper discusses the L-coil system design and its observed cryogenic performance.

  4. Biomaterials Made from Coiled-Coil Peptides.

    Science.gov (United States)

    Conticello, Vincent; Hughes, Spencer; Modlin, Charles

    The development of biomaterials designed for specific applications is an important objective in personalized medicine. While the breadth and prominence of biomaterials have increased exponentially over the past decades, critical challenges remain to be addressed, particularly in the development of biomaterials that exhibit highly specific functions. These functional properties are often encoded within the molecular structure of the component molecules. Proteins, as a consequence of their structural specificity, represent useful substrates for the construction of functional biomaterials through rational design. This chapter provides an in-depth survey of biomaterials constructed from coiled-coils, one of the best-understood protein structural motifs. We discuss the utility of this structurally diverse and functionally tunable class of proteins for the creation of novel biomaterials. This discussion illustrates the progress that has been made in the development of coiled-coil biomaterials by showcasing studies that bridge the gap between the academic science and potential technological impact.

  5. Avaliacão de programas de aquecimento para espectrometria de absorção atômica com atomizacão eletrotérmica em filamento de tungstênio Evaluation of heating programs for electrothermal atomic absorption spectrometry using a tungsten coil

    Directory of Open Access Journals (Sweden)

    Pedro V. Oliveira

    2000-10-01

    Full Text Available A tungsten coil atomizer was used to investigate the effect of heating programs with constant or variable drying temperatures on the atomization of Al, Cd, Cr and Pb. The variation of the surface temperature in the tungsten coil furnace can occur during each heating step due to the design of the power supply, that may apply constant voltages during a programmed time. For volatile elements (Cd, losses in sensitivity were observed when the program with a variable temperature was used. On the other hand, these effects are negligible for less volatile elements (Al and Cr and any tested program, in different acidic media, could be used without appreciable changes in sensitivities. The results allow the establishment of proper heating programs for elements with different thermochemical behavior in the tungsten coil atomizer.

  6. IMPACT OF GEOTHERMAL GRADIENT ON GROUND SOURCE HEAT PUMP SYSTEM MODELING

    OpenAIRE

    Tomislav Kurevija; Domagoj Vulin; Marija Macenić

    2014-01-01

    ndisturbed ground temperature is one of the most crucial thermogeological parameters needed for shallow geothermal resources assessment. Energy considered to be geothermal is energy stored in the ground at depths where solar radiation has no effect. At depth where undisturbed ground temperature occurs there is no influence of seasonal variations in air temperature from surface. Exact temperature value, and depth where it occurs, is functionally dependent on surface climate parameters and ther...

  7. Experimental study of a solar-assisted ground-coupled heat pump system with solar seasonal thermal storage in severe cold areas

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao; Zheng, Maoyu; Zhang, Wenyong; Zhang, Shu; Yang, Tao [School of Municipal and Environmental Engineering, Harbin Institute of Technology, NO 202 Haihe Road, Harbin, Hei Longjiang 150090 (China)

    2010-11-15

    This paper presents the experimental study of a solar-assisted ground-coupled heat pump system (SAGCHPS) with solar seasonal thermal storage installed in a detached house in Harbin. The solar seasonal thermal storage was conducted throughout the non-heating seasons. In summer, the soil was used as the heat sink to cool the building directly. In winter, the solar energy was used as a priority, and the building was heated by a ground-coupled heat pump (GCHP) and solar collectors alternately. The results show that the system can meet the heating-cooling energy needs of the building. In the heating mode, the heat directly supplied by solar collectors accounted for 49.7% of the total heating output, and the average coefficient of performance (COP) of the heat pump and the system were 4.29 and 6.55, respectively. In the cooling mode, the COP of the system reached 21.35, as the heat pump was not necessary to be started. After a year of operation, the heat extracted from the soil by the heat pump accounted for 75.5% of the heat stored by solar seasonal thermal storage. The excess heat raised the soil temperature to a higher level, which was favorable for increasing the COP of the heat pump. (author)

  8. Performance Evaluation of Radiator and Radiant Floor Heating Systems for an Office Room Connected to a Ground-Coupled Heat Pump

    Directory of Open Access Journals (Sweden)

    Ioan Sarbu

    2016-03-01

    Full Text Available A ground-coupled heat pump (GCHP system used to provide the space heating for an office room is a renewable, high performance technology. This paper discusses vapour compression-based HP systems, briefly describing the thermodynamic cycle calculations, as well as the coefficient of performance (COP and CO2 emissions of a HP with an electro-compressor and compares different heating systems in terms of energy consumption, thermal comfort and environmental impact. It is focused on an experimental study performed to test the energy efficiency of the radiator or radiant floor heating system for an office room connected to a GCHP. The main performance parameters (COP and CO2 emissions are obtained for one month of operation of the GCHP system, and a comparative analysis of these parameters is presented. Additionally, two numerical simulation models of useful thermal energy and the system COP in heating mode are developed using the Transient Systems Simulation (TRNSYS software. Finally, the simulations obtained from TRNSYS software are analysed and compared to the experimental data, showing good agreement and thus validating the simulation models.

  9. Air/ground heat exchanger (GHE): Modelling, design, performance; Luft-/Erdwaermetauscher EWT: Modellierung, Auslegung und Betriebserfahrungen

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, A. [Fraunhofer-Inst. fuer Solare Energiesysteme, Freiburg (Germany); Pfafferott, J. [Energieversorgung Spree-Schwarze Elster AG (ESSAG), Cottbus (Germany); Dibowski, G. [Deutsches Zentrum fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Abt. Sonnenofen

    1998-02-01

    Air/Ground Heat Exchanger (GHE) utilize soil for seasonal heat storage and are used for air preheating or -cooling. Design and layout require suitable tools which adequately describe the complex heat temperature mechanisms in soils. Since heat densities in soil and heat exchange coefficients between air and GHE are both low, a detailed characterization of the soil and a precise modeling of the heat exchange processes within the GHE are needed. Tools for the design and yield prediction of GHE are presented by way of examples. Results are compared with measured data and both opportunities and limitations of GHEs are discussed using calculated and actual data. (orig.) [Deutsch] Luft-/Erdwaermetauscher EWT nutzen das Erdreich als saisonalen Energiespeicher, sie werden beispielsweise zur Zuluft-Vorerwaermung oder -kuehlung eingesetzt. Die Planung und Auslegung von Luft-/Erdwaermetauschern erfordert geeignete Hilfsmittel, um das komplizierte Temperaturfeld im Erdreich mit ausreichender Genauigkeit abbilden zu koennen. Da die Waermestromdichten im Erdreich und der Waermeuebergang zwischen der Luft im Luft-/Erdwaermetauscher und dem umgebenden Erdreich gering sind, ist sowohl eine detaillierte Abbildung des Erdreichs als auch die Modellierung des Waermeuebergangs im Luft-/Erdwaermetauscher erforderlich. Verfahren zur Auslegung und Ertragsvorhersage von Luft-/Erdwaermetauschern werden vorgestellt und deren Anwendung demonstriert. Die Ergebnisse werden mit Betriebserfahrungen von realisierten Luft-/Erdwrmetauschern verglichen. Moeglichkeiten und Grenzen von Luft-/Erdwaermetauschern werden anhand von Praxis und Simulationsrechnungen diskutiert. (orig.)

  10. Investigations and model validation of a ground-coupled heat pump for the combination with solar collectors

    International Nuclear Information System (INIS)

    Pärisch, Peter; Mercker, Oliver; Warmuth, Jonas; Tepe, Rainer; Bertram, Erik; Rockendorf, Gunter

    2014-01-01

    The operation of ground-coupled heat pumps in combination with solar collectors requires comprising knowledge of the heat pump behavior under non-standard conditions. Especially higher temperatures and varying flow rates in comparison to non-solar systems have to be taken into account. Furthermore the dynamic behavior becomes more important. At ISFH, steady-state and dynamic tests of a typical brine/water heat pump have been carried out in order to analyze its behavior under varying operation conditions. It has been shown, that rising source temperatures do only significantly increase the coefficient of performance (COP), if the source temperature is below 10–20 °C, depending on the temperature lift between source and sink. The flow rate, which has been varied both on the source and the sink side, only showed a minor influence on the exergetic efficiency. Additionally a heat pump model for TRNSYS has been validated under non-standard conditions. The results are assessed by means of TRNSYS simulations. -- Highlights: • A brine/water heat pump was tested under steady-state and transient conditions. • Decline of exergetic efficiency at low temperature lifts, no influence of flow rate. • Expected improvement by reciprocating compressor and electronic expansion valve for solar assisted heat source. • A TRNSYS black box model (YUM) was validated and a flow rate correction was proven • The start-up behavior is a very important parameter for system simulations

  11. Superconducting magnetic coil

    Science.gov (United States)

    Aized, Dawood; Schwall, Robert E.

    1996-06-11

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  12. Mitigation potential of horizontal ground coupled heat pumps for current and future climatic conditions: UK environmental modelling and monitoring studies

    Science.gov (United States)

    García González, Raquel; Verhoef, Anne; Vidale, Pier Luigi; Gan, Guohui; Wu, Yupeng; Hughes, Andrew; Mansour, Majdi; Blyth, Eleanor; Finch, Jon; Main, Bruce

    2010-05-01

    An increased uptake of alternative low or non-CO2 emitting energy sources is one of the key priorities for policy makers to mitigate the effects of environmental change. Relatively little work has been undertaken on the mitigation potential of Ground Coupled Heat Pumps (GCHPs) despite the fact that a GCHP could significantly reduce CO2 emissions from heating systems. It is predicted that under climate change the most probable scenario is for UK temperatures to increase and for winter rainfall to become more abundant; the latter is likely to cause a general rise in groundwater levels. Summer rainfall may reduce considerably, while vegetation type and density may change. Furthermore, recent studies underline the likelihood of an increase in the number of heat waves. Under such a scenario, GCHPs will increasingly be used for cooling as well as heating. These factors will affect long-term performance of horizontal GCHP systems and hence their economic viability and mitigation potential during their life span ( 50 years). The seasonal temperature differences encountered in soil are harnessed by GCHPs to provide heating in the winter and cooling in the summer. The performance of a GCHP system will depend on technical factors (heat exchanger (HE) type, length, depth, and spacing of pipes), but also it will be determined to a large extent by interactions between the below-ground parts of the system and the environment (atmospheric conditions, vegetation and soil characteristics). Depending on the balance between extraction and rejection of heat from and to the ground, the soil temperature in the neighbourhood of the HE may fall or rise. The GROMIT project (GROund coupled heat pumps MITigation potential), funded by the Natural Environment Research Council (UK), is a multi-disciplinary research project, in collaboration with EarthEnergy Ltd., which aims to quantify the CO2 mitigation potential of horizontal GCHPs. It considers changing environmental conditions and combines

  13. The JET divertor coil

    International Nuclear Information System (INIS)

    Last, J.R.; Froger, C.; Sborchia, C.

    1989-01-01

    The divertor coil is mounted inside the Jet vacuum vessel and is able to carry 1 MA turns. It is of conventional construction - water cooled copper, epoxy glass insulation -and is contained in a thin stainless steel case. The coil has to be assembled, insulated and encased inside the Jet vacuum vessel. A description of the coil is given, together with technical information (including mechanical effects on the vacuum vessel), an outline of the manufacture process and a time schedule. (author)

  14. Ground source heat pumps designed for earth-sheltered, low-energy atrium building

    NARCIS (Netherlands)

    Pawlovski, A.; Heim, D.; Hensen, J.L.M.

    2003-01-01

    One of the main strategies in design of earth-sheltered buildings is to reduce heat losses in the winter and heat gains in the summer by using the relatively stable thermal conditions of the soil. Additionally, construction work carried out at the site allows a reduction of the installation costs

  15. Recovery Act: Tennessee Energy Efficient Schools Initiative Ground Source Heat Pump Program

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Terry [Townsend Engineering, Inc., Davenport, IA (United States); Slusher, Scott [Townsend Engineering, Inc., Davenport, IA (United States)

    2017-04-24

    The Tennessee Energy Efficient Schools Initiative (EESI) Hybrid-Water Source Heat Pump (HY-GSHP) Program sought to provide installation costs and operation costs for different Hybrid water source heat pump systems’ configurations so that other State of Tennessee School Districts will have a resource for comparison purposes if considering a geothermal system.

  16. Solar Assisted Ground Source Heat Pump Performance in Nearly Zero Energy Building in Baltic Countries

    Science.gov (United States)

    Januševičius, Karolis; Streckienė, Giedrė

    2013-12-01

    In near zero energy buildings (NZEB) built in Baltic countries, heat production systems meet the challenge of large share domestic hot water demand and high required heating capacity. Due to passive solar design, cooling demand in residential buildings also needs an assessment and solution. Heat pump systems are a widespread solution to reduce energy use. A combination of heat pump and solar thermal collectors helps to meet standard requirements and increases the share of renewable energy use in total energy balance of country. The presented paper describes a simulation study of solar assisted heat pump systems carried out in TRNSYS. The purpose of this simulation was to investigate how the performance of a solar assisted heat pump combination varies in near zero energy building. Results of three systems were compared to autonomous (independent) systems simulated performance. Different solar assisted heat pump design solutions with serial and parallel solar thermal collector connections to the heat pump loop were modelled and a passive cooling possibility was assessed. Simulations were performed for three Baltic countries: Lithuania, Latvia and Estonia.

  17. Stress relaxation in SSC 50mm dipole coils

    International Nuclear Information System (INIS)

    Rogers, D.; Markley, F.

    1992-04-01

    We are measuring the stress relaxation of SSC 50mm outer coils with the goal of predicting how much of the coil prestress will be lost while the coils are warehoused between manufacture and cooldown. We manufacture 3 inch (76.2mm) long segments of coil with the same materials and techniques that have been used for prototype coils. We are running four simultaneous tests in an attempt to separate the contributions of the different coil materials. Test one is a completely insulated coil section where the insulation is the all polyamide system being tested at Brookhaven; test two is a wire stack insulated only with the normal Kapton overwrap; test three is a stack of bare cable; and test four is a completely insulated normal coil section. All, except for the bare cable, include the ground insulation. The insulated coil sections are carefully dried before loading and testing in order to eliminate stress changes due to varying moisture content. The temperature dependence of the stress relaxation is being studied separately. Three companion papers presented at this conference will be: (1) ''Temperature dependence of the viscoelastic properties of SSC coil insulation'' (2) ''Measurement of the elastic modulus of Kapton perpendicular to the plane of the film at room and cryogenic temperatures'' (3) ''Theoretical methods for creep and stress relaxation studies of SSC coil.''

  18. Permafrost thawing in organic Arctic soils accelerated by ground heat production

    DEFF Research Database (Denmark)

    Hollesen, Jørgen; Matthiesen, Henning; Møller, Anders Bjørn

    2015-01-01

    Decomposition of organic carbon from thawing permafrost soils and the resulting release of carbon to the atmosphere are considered to represent a potentially critical global-scale feedback on climate change1, 2. The accompanying heat production from microbial metabolism of organic material has been...... recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon3, 4. This internal heat production is poorly understood, however, and the strength of this effect remains unclear3. Here, we have quantified the variability of heat production in contrasting...... organic permafrost soils across Greenland and tested the hypothesis that these soils produce enough heat to reach a tipping point after which internal heat production can accelerate the decomposition processes. Results show that the impact of climate changes on natural organic soils can be accelerated...

  19. Heat dissipation computations of a HVDC ground electrode using a supercomputer

    International Nuclear Information System (INIS)

    Greiss, H.; Mukhedkar, D.; Lagace, P.J.

    1990-01-01

    This paper reports on the temperature, of soil surrounding a High Voltage Direct Current (HVDC) toroidal ground electrode of practical dimensions, in both homogeneous and non-homogeneous soils that was computed at incremental points in time using finite difference methods on a supercomputer. Curves of the response were computed and plotted at several locations within the soil in the vicinity of the ground electrode for various values of the soil parameters

  20. Study on the Optimizing Operation of Exhaust Air Heat Recovery and Solar Energy Combined Thermal Compensation System for Ground-Coupled Heat Pump

    Directory of Open Access Journals (Sweden)

    Kuan Wang

    2017-01-01

    Full Text Available This study proposed an exhaust air heat recovery and solar energy combined thermal compensation system (ESTC for ground-coupled heat pumps. Based on the prediction of the next day’s exhaust air temperature and solar irradiance, an optimized thermal compensation (OTC method was developed in this study as well, in which the exhaust air heat recovery compensator and solar energy compensator in the ESTC system run at high efficiency throughout various times of day. Moreover, a modified solar term similar days group (STSDG method was proposed to improve the accuracy of solar irradiance prediction in hazy weather. This modified STSDG method was based on air quality forecast and AQI (air quality index correction factors. Through analyzing the operating parameters and the simulation results of a case study, the ESTC system proved to have good performance and high efficiency in eliminating the heat imbalance by using the OTC method. The thermal compensation quantity per unit energy consumption (TEC of ESTC under the proposed method was 1.25 times as high as that under the traditional operation method. The modified STSDG method also exhibited high accuracy. For the accumulated solar irradiance of the four highest daily radiation hours, the monthly mean absolute percentage error (MAPE between the predicted values and the measured values was 6.35%.

  1. Forecasting of a ground-coupled heat pump performance using neural networks with statistical data weighting pre-processing

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23279 Elazig (Turkey); Sengur, Abdulkadir [Department of Electronic and Computer Science, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey)

    2008-04-15

    The objective of this work is to improve the performance of an artificial neural network (ANN) with a statistical weighted pre-processing (SWP) method to learn to predict ground source heat pump (GCHP) systems with the minimum data set. Experimental studies were completed to obtain training and test data. Air temperatures entering/leaving condenser unit, water-antifreeze solution entering/leaving the horizontal ground heat exchangers and ground temperatures (1 and 2 m) were used as input layer, while the output is coefficient of performance (COP) of system. Some statistical methods, such as the root-mean squared (RMS), the coefficient of multiple determinations (R{sup 2}) and the coefficient of variation (cov) is used to compare predicted and actual values for model validation. It is found that RMS value is 0.074, R{sup 2} value is 0.9999 and cov value is 2.22 for SCG6 algorithm of only ANN structure. It is also found that RMS value is 0.002, R{sup 2} value is 0.9999 and cov value is 0.076 for SCG6 algorithm of SWP-ANN structure. The simulation results show that the SWP based networks can be used an alternative way in these systems. Therefore, instead of limited experimental data found in literature, faster and simpler solutions are obtained using hybridized structures such as SWP-ANN. (author)

  2. Performance and costs of a roof-sized PV/thermal array combined with a ground coupled heat pump

    International Nuclear Information System (INIS)

    Bakker, M.; Zondag, H.A.; Elswijk, M.J.; Strootman, K.J.; Jong, M.J.M.

    2005-03-01

    A photovoltaic/thermal (PVT) panel is a combination of photovoltaic cells with a solar thermal collector, generating solar electricity and solar heat simultaneously. Hence, PVT panels are an alternative for a combination of separate PV panels and solar thermal collectors. A promising system concept, consisting of 25 m 2 of PVT panels and a ground coupled heat pump, has been simulated in TRNSYS. It has been found that this system is able to cover 100% of the total heat demand for a typical newly-built Dutch one-family dwelling, while covering nearly all of its own electricity use and keeping the long-term average ground temperature constant. The cost of such a system has been compared to the cost of a reference system, where the PVT panels have been replaced with separate PV panels (26 m 2 ) and solar thermal collectors (7 m 2 ), but which is otherwise identical. The electrical and thermal yield of this reference system is equal to that of the PVT system. It has been found that both systems require a nearly identical initial investment. Finally, a view on future PVT markets is given. In general, the residential market is by far the most promising market. The system discussed in this paper is expected to be most successful in newly-built low-energy housing concepts

  3. A techno-economic comparison of ground-coupled and air-coupled heat pump system for space cooling

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, University of Firat, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, University of Firat, 23119 Elazig (Turkey)

    2007-05-15

    This paper reports a techno-economic comparison between a ground-coupled heat pump (GCHP) system and an air-coupled heat pump (ACHP) system. The systems connected to a test room in Firat University, Elazig (38.41{sup o}N, 39.14{sup o}E), Turkey, were designed and constructed for space cooling. The performances of the GCHP and the ACHP system were experimentally determined. The experimental results were obtained from June to September in cooling season of 2004. The average cooling performance coefficients (COP{sub sys}) of the GCHP system for horizontal ground heat exchanger (HGHE) in the different trenches, at 1 and 2m depths, were obtained to be 3.85 and 4.26, respectively and the COP{sub sys} of the ACHP system was determined to be 3.17. The test results indicate that system parameters can have an important effect on performance, and that GCHP systems are economically preferable to ACHP systems for the purpose of space cooling. (author)

  4. Heat flow and subsurface temperature as evidence for basin-scale ground-water flow, North Slope of Alaska

    Science.gov (United States)

    Deming, D.; Sass, J.H.; Lachenbruch, A.H.; De Rito, R. F.

    1992-01-01

    Several high-resolution temperature logs were made in each of 21 drillholes and a total of 601 thermal conductivity measurements were made on drill cuttings and cores. Near-surface heat flow (??20%) is inversely correlated with elevation and ranges from a low of 27 mW/m2 in the foothills of the Brooks Range in the south, to a high of 90 mW/m2 near the north coast. Subsurface temperatures and thermal gradients estimated from corrected BHTs are similarly much higher on the coastal plain than in the foothills province to the south. Significant east-west variation in heat flow and subsurface temperature is also observed; higher heat flow and temperature coincide with higher basement topography. The observed thermal pattern is consistent with forced convection by a topographically driven ground-water flow system. Average ground-water (Darcy) velocity in the postulated flow system is estimated to be of the order of 0.1 m/yr; the effective basin-scale permeability is estimated to be of the order of 10-14 m2. -from Authors

  5. Performance and costs of a roof-sized PV/thermal array combined with a ground coupled heat pump

    International Nuclear Information System (INIS)

    Bakker, M.; Zondag, H.A.; Elswijk, M.J.; Strootman, K.J.; Jong, M.J.M.

    2005-01-01

    A photovoltaic/thermal (PVT) panel is a combination of photovoltaic cells with a solar thermal collector, generating solar electricity and solar heat simultaneously. Hence, PVT panels are an alternative for a combination of separate PV panels and solar thermal collectors. A promising system concept, consisting of 25 m 2 of PVT panels and a ground coupled heat pump, has been simulated in TRNSYS. It has been found that this system is able to cover 100% of the total heat demand for a typical newly-built Dutch one-family dwelling, while covering nearly all of its own electricity use and keeping the long-term average ground temperature constant. The cost of such a system has been compared to the cost of a reference system, where the PVT panels have been replaced with separate PV panels (26 m 2 ) and solar thermal collectors (7 m 2 ), but which is otherwise identical. The electrical and thermal yield of this reference system is equal to that of the PVT system. It has been found that both systems require a nearly identical initial investment. Finally, a view on future PVT markets is given. In general, the residential market is by far the most promising market. The system discussed in this paper is expected to be most successful in newly-built low-energy housing concepts. (Author)

  6. Stability analysis of high temperature superconducting coil in liquid hydrogen

    International Nuclear Information System (INIS)

    Nakayama, T.; Yagai, T.; Tsuda, M.; Hamajima, T.

    2007-01-01

    Recently, it is expected that hydrogen plays an important role in energy source including electric power in near future. Liquid hydrogen has high potential for cooling down superconducting coil wound with high temperature superconductors (HTS), such as BSCCO, YBCO. In this paper, we study stabilities of the coils wound with BSCCO tapes, which are immersed in the liquid hydrogen, and compare stability results with those cooled by liquid helium. We treat a minimum propagation zone (MPZ) theory to evaluate the coil stability considering boiling heat flux of the liquid hydrogen, and specific heat, heat conduction and resistivity of HTS materials as a function of temperature. It is found that the coil cooled by the liquid hydrogen has higher stability margin than that cooled by the liquid helium. We compare the stability margins of both coils wound with Bi-2223/Ag tape and Bi-2212/Ag tape in liquid hydrogen. As a result, it is found that the stability of Bi-2212 coil is equivalent to that of Bi-2223 coil in low and high magnetic field, while the maximum current of Bi-2212 coil exceeds a little bit that of Bi-2223 coil in both magnetic fields

  7. Thermal analysis of the position of the freezing front around an LNG in-ground storage tank with a heat barrier

    Science.gov (United States)

    Watanabe, O.; Tanaka, M.

    A technique of controlling the extent of the freezing zone created by in ground liquefied natural gas storage tanks by installing a heat barrier is described. The freezing conditions around three representative tanks after operating the system were compared.

  8. First assembly phase for the ATLAS toroid coils

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The ATLAS barrel toroid system consists of eight coils, each of axial length 25.3 m, assembled radially and symmetrically around the beam axis. The coils are of a flat racetrack type with two double-pancake windings made of 20.5 kA aluminium-stabilized niobium-titanium superconductor. In the first phase of assembly, the two 'pancakes' are packed into their vacuum vessel. This is done using bladders filled with resin and glass microbeads under pressure. The resin is heated and, once cooled, holds the pancakes in place. The operation has to be performed on both sides of the coil, which necessitated a special technique to turn the coils over and then transport them to the heating table. Photos 01, 02, 03: Transporting the coil to the heating table using a special lifting gantry manufactured at JINR-Dubna, Russia in preparation for the 'bladderisation' operation.

  9. Shallow Groundwater Temperatures and the Urban Heat Island Effect: the First U.K City-wide Geothermal Map to Support Development of Ground Source Heating Systems Strategy

    Science.gov (United States)

    Patton, Ashley M.; Farr, Gareth J.; Boon, David P.; James, David R.; Williams, Bernard; Newell, Andrew J.

    2015-04-01

    The first UK city-wide heat map is described based on measurements of groundwater from a shallow superficial aquifer in the coastal city of Cardiff, Wales, UK. The UK Government has a target of reducing greenhouse gas emissions by 80% by 2050 (Climate Change Act 2008) and low carbon technologies are key to achieving this. To support the use of ground source heating we characterised the shallow heat potential of an urban aquifer to produce a baseline dataset which is intended to be used as a tool to inform developers and to underpin planning and regulation. We exploited an existing network of 168 groundwater monitoring boreholes across the city, recording the water temperature in each borehole at 1m depth intervals up to a depth of 20m. We recorded groundwater temperatures during the coldest part of 2014, and repeat profiling of the boreholes in different seasons has added a fourth dimension to our results and allowed us to characterise the maximum depth of seasonal temperature fluctuation. The temperature profiles were used to create a 3D model of heat potential within the aquifer using GOCAD® and the average borehole temperatures were contoured using Surfer® 10 to generate a 2D thermal resource map to support future assessment of urban Ground Source Heat Pumps prospectively. The average groundwater temperature in Cardiff was found to be above the average for England and Wales (11.3°C) with 90% of boreholes in excess of this figure by up to 4°C. The subsurface temperature profiles were also found to be higher than forecast by the predicted geothermal gradient for the area. Potential sources for heat include: conduction from buildings, basements and sub-surface infrastructure; insulation effects of the urban area and of the geology, and convection from leaking sewers. Other factors include recharge inhibition by drains, localised confinement and rock-water interaction in specific geology. It is likely to be a combination of multiple factors which we are hoping

  10. Study on hybrid ground-coupled heat pump system for air-conditioning in hot-weather areas like Hong Kong

    International Nuclear Information System (INIS)

    Man, Yi; Yang, Hongxing; Wang, Jinggang

    2010-01-01

    The ground-coupled heat pump (GCHP) system is becoming attractive for air-conditioning in some moderate-weather regions due to its high energy efficiency and reliable operation capability. However, when the technology is used in buildings where there is only cooling load in hot-weather areas like Hong Kong, the heat rejected into the ground by the GCHP systems will accumulate around the ground heat exchangers (GHE). This heat accumulation will result in degradation of system performance and increment of system operating costs. This problem can be resolved by using the hybrid ground-coupled heat pump (HGCHP) system, which uses supplemental heat rejecters to reject the accumulated heat. This paper presents a practical hourly simulation model of the HGCHP system by modeling the heat transfer process of the system's main components. The computer program based on this hourly simulation model can be used to calculate the hour-by-hour operation data of the HGCHP system. As a case study, both a HGCHP system and a traditional GCHP system are designed for a hypothetic private residential building located in Hong Kong, and the economic comparisons are conducted between these two types of systems. The simulation results show that the HGCHP system can effectively solve the heat accumulation problem and reduce both the initial costs and operating costs of the air-conditioning system in the building.

  11. Study on hybrid ground-coupled heat pump system for air-conditioning in hot-weather areas like Hong Kong

    Energy Technology Data Exchange (ETDEWEB)

    Man, Yi; Yang, Hongxing [Renewable Energy Research Group, Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Wang, Jinggang [Hebei University of Engineering, Handan (China)

    2010-09-15

    The ground-coupled heat pump (GCHP) system is becoming attractive for air-conditioning in some moderate-weather regions due to its high energy efficiency and reliable operation capability. However, when the technology is used in buildings where there is only cooling load in hot-weather areas like Hong Kong, the heat rejected into the ground by the GCHP systems will accumulate around the ground heat exchangers (GHE). This heat accumulation will result in degradation of system performance and increment of system operating costs. This problem can be resolved by using the hybrid ground-coupled heat pump (HGCHP) system, which uses supplemental heat rejecters to reject the accumulated heat. This paper presents a practical hourly simulation model of the HGCHP system by modeling the heat transfer process of the system's main components. The computer program based on this hourly simulation model can be used to calculate the hour-by-hour operation data of the HGCHP system. As a case study, both a HGCHP system and a traditional GCHP system are designed for a hypothetic private residential building located in Hong Kong, and the economic comparisons are conducted between these two types of systems. The simulation results show that the HGCHP system can effectively solve the heat accumulation problem and reduce both the initial costs and operating costs of the air-conditioning system in the building. (author)

  12. Study on hybrid ground-coupled heat pump system for air-conditioning in hot-weather areas like Hong Kong

    Energy Technology Data Exchange (ETDEWEB)

    Man, Y.; Yang, H.X. [Hong Kong Polytechnic Univ., Renewable Energy Research Group, Hung Hom, Kowloon, (Hong Kong). Dept. of Building Services Engineering

    2008-07-01

    Due to its high energy efficiency and reliable operation capability, the ground-coupled heat pump (GCHP) system is becoming attractive for air-conditioning in some moderate-weather regions. However, when the technology is used in buildings where there is only cooling load in hot-weather areas such as Hong Kong, the heat rejected into the ground by the GCHP systems will accumulate around the ground heat exchangers (GHE), resulting in degradation of system performance and increased system operating costs. This problem can be resolved by using a hybrid ground-coupled heat pump (HGCHP) system, as it uses supplemental heat rejecters to reject the accumulated heat. By modeling the heat transfer process of the system's main components, this paper presented a practical hourly simulation model of the HGCHP system. Based on this hourly simulation model, the computer program could be used to calculate the hour-by-hour operation data of the HGCHP system according to the cooling and hot water heating loads of a building. The paper discussed a case study that involved a design of both a HGCHP system and a traditional GCHP system for a hypothetical private residential building located in Hong Kong. The economic comparisons were performed between these two types of systems. It was concluded through the simulations that the HGCHP system could effectively solve the heat accumulation problem and reduce both the initial cost and operating cost of the air-conditioning system in the building. 19 refs., 1 tab., 13 figs.

  13. Optimization of ground source heat pumps systems through the implementation of hybrid systems; Optimizacion de las instalaciones de bomba de calor geotermica mediante la implementacion de sistemas hibridos

    Energy Technology Data Exchange (ETDEWEB)

    Magraner, T.; Quilis, M. S.; Martinez, S.

    2009-07-01

    One of the fundamental aspects to consider in the design of a ground heat pump system is the heat balance in the ground since thermal saturation of the ground produces a decreasing of the performance of the system throughout its useful life. The hybrid geothermal system which combined geothermal heat pump system with other systems for generation or dissipation energy are very suitable for balancing the heat exchanger meters needed for the proper functioning of the system, important aspect to reduce costs and achieve attractive return periods of the initial investment. Energesis Ingenieria has developed and implemented in two office buildings, a design of hybrid systems based on the combination of a geothermal heat pump and air-condensed units (dry coolers) that can ensure energy efficiencies comparable to geothermal pure systems, reducing substantially the investment cost. (Author) 5 refs.

  14. Nanofluids and a method of making nanofluids for ground source heat pumps and other applications

    Science.gov (United States)

    Olson, John Melvin

    2013-11-12

    This invention covers nanofluids. Nanofluids are a combination of particles between 1 and 100 nanometers, a surfactant and the base fluid. The nanoparticles for this invention are either pyrogenic nanoparticles or carbon nanotubes. These nanofluids improve the heat transfer of the base fluids. The base fluid can be ethylene glycol, or propylene glycol, or an aliphatic-hydrocarbon based heat transfer fluid. This invention also includes a method of making nanofluids. No surfactant is used to suspend the pyrogenic nanoparticles in glycols.

  15. The Netherlands. Complex ground source heat drilling for horticultural works; Niederlande. Komplexe Erdwaermebohrung fuer Gartenbaubetriebe

    Energy Technology Data Exchange (ETDEWEB)

    Kilian, Dieter [DrillTec GUT GmbH, Deggendorf (Germany)

    2012-11-01

    For the past six months, the Dutch gardening industry looked to Honselersdijk near Rotterdam with great expectations. There, five market gardening businesses planned to heat their greenhouses with geothermal heat instead of natural gas. After technically complex drilling operations, hot water is now flowing at a rate of up to 50 litres per second; the drilling project remained fascinating to the last for everybody involved.

  16. Active internal corrector coils

    International Nuclear Information System (INIS)

    Thompson, P.A.; Cottingham, J.; Dahl, P.

    1986-01-01

    Trim or corrector coils to correct main magnet field errors and provide higher multipole fields for beam optics purposes are a standard feature of superconducting magnet accelerator systems. This paper describes some of the design and construction features of powered internal trim coils and a sampling of the test results obtained

  17. Compact stellarator coils

    International Nuclear Information System (INIS)

    Pomphrey, N.; Berry, L.A.; Boozer, A.H.

    2001-01-01

    Experimental devices to study the physics of high-beta (β>∼4%), low aspect ratio (A<∼4.5) stellarator plasmas require coils that will produce plasmas satisfying a set of physics goals, provide experimental flexibility, and be practical to construct. In the course of designing a flexible coil set for the National Compact Stellarator Experiment, we have made several innovations that may be useful in future stellarator design efforts. These include: the use of Singular Value Decomposition methods for obtaining families of smooth current potentials on distant coil winding surfaces from which low current density solutions may be identified; the use of a Control Matrix Method for identifying which few of the many detailed elements of the stellarator boundary must be targeted if a coil set is to provide fields to control the essential physics of the plasma; the use of Genetic Algorithms for choosing an optimal set of discrete coils from a continuum of potential contours; the evaluation of alternate coil topologies for balancing the tradeoff between physics objective and engineering constraints; the development of a new coil optimization code for designing modular coils, and the identification of a 'natural' basis for describing current sheet distributions. (author)

  18. Liquid rope coiling

    NARCIS (Netherlands)

    Ribe, N.M.; Habibi, M.; Bonn, D.

    2012-01-01

    A thin stream or rope of viscous fluid falling from a sufficient height onto a surface forms a steadily rotating helical coil. Tabletop laboratory experiments in combination with a numerical model for slender liquid ropes reveal that finite-amplitude coiling can occur in four distinct regimes

  19. Modeling ground thermal regime of an ancient buried ice body in Beacon Valley, Antarctica using a 1-D heat equation with latent heat effect

    Science.gov (United States)

    Liu, L.; Sletten, R. S.; Hallet, B.; Waddington, E. D.; Wood, S. E.

    2013-12-01

    An ancient massive ice body buried under several decimeters of debris in Beacon Valley, Antarctica is believed to be over one million years old, making it older than any known glacier or ice cap. It is fundamentally important as a reservoir of water, proxy for climatic information, and an expression of the periglacial landscape. It is also one of Earth's closest analog for widespread, near-surface ice found in Martian soils and ice-cored landforms. We are interested in understanding controls on how long this ice may persist since our physical model of sublimation suggests it should not be stable. In these models, the soil temperatures and the gradient are important because it determines the direction and magnitude of the vapor flux, and thus sublimation rates. To better understand the heat transfer processes and constrain the rates of processes governing ground ice stability, a model of the thermal behavior of the permafrost is applied to Beacon Valley, Antarctica. It calculates soil temperatures based on a 1-D thermal diffusion equation using a fully implicit finite volume method (FVM). This model is constrained by soil physical properties and boundary conditions of in-situ ground surface temperature measurements (with an average of -23.6oC, a maximum of 20.5oC and a minimum of -54.3oC) and ice-core temperature record at ~30 m. Model results are compared to in-situ temperature measurements at depths of 0.10 m, 0.20 m, 0.30 m, and 0.45 m to assess the model's ability to reproduce the temperature profile for given thermal properties of the debris cover and ice. The model's sensitivity to the thermal diffusivity of the permafrost and the overlaying debris is also examined. Furthermore, we incorporate the role of ice condensation/sublimation which is calculated using our vapor diffusion model in the 1-D thermal diffusion model to assess potential latent heat effects that in turn affect ground ice sublimation rates. In general, the model simulates the ground thermal

  20. Integration of solar heat storage in the ground floor; Bygningsintegreret varmelagring af solvarme i terraendaek

    Energy Technology Data Exchange (ETDEWEB)

    Weitzmann, P.; Holck, O.; Svendsen, S.

    2001-07-01

    In this report the thermal properties of heat storage of solar heating in floors is examined. The floor examined is built using two decks, where the lower can be used for heat storage. It is the purpose of the work that has been carried out, to be able to quantify the potential for a reduction of the heating demand in a house, through the use of heat storage of solar heating. The report starts out with an introduction to the problem that is to be examined, namely to perform detailed calculations of the temperature and heat flows in floors. A description of the theory for the implementation of the model for solar collector, solar tank, floor, foundation and control strategies, can be found. The model described here has been implemented into the programming language Matlab and Simulink. Especially the model of the floor is described in great detail. The section begins with a description of the floor construction. It is then described how the floor construction is implemented into a detailed finite element model, and converted into a less detailed RC-model, where the temperature is calculated only in a few points. Each of the points had a heat capacity, and between the points a thermal resistance is included. The reason for using a RC-model is, that it proved impossible to do yearly calculations using the finite element model because of unacceptably long calculation times. Instead the procedure for the conversion between the two models is shown. After the conversion results from the two methods are compared to estimate the error introduced by this conversion to a less detailed model. The two methods are found to differ only by around 5%. The coefficients to be used in the RC-model are shown for seven different layouts of the floor concerning pipe spacing, distribution of insulation, thickness of heat storage layer and type of heat storage layer (sand or concrete). A number of different control strategies for the distribution of flow in solar tank and heat storage

  1. Molecular basis of coiled-coil oligomerization-state specificity.

    Science.gov (United States)

    Ciani, Barbara; Bjelic, Saša; Honnappa, Srinivas; Jawhari, Hatim; Jaussi, Rolf; Payapilly, Aishwarya; Jowitt, Thomas; Steinmetz, Michel O; Kammerer, Richard A

    2010-11-16

    Coiled coils are extensively and successfully used nowadays to rationally design multistranded structures for applications, including basic research, biotechnology, nanotechnology, materials science, and medicine. The wide range of applications as well as the important functions these structures play in almost all biological processes highlight the need for a detailed understanding of the factors that control coiled-coil folding and oligomerization. Here, we address the important and unresolved question why the presence of particular oligomerization-state determinants within a coiled coil does frequently not correlate with its topology. We found an unexpected, general link between coiled-coil oligomerization-state specificity and trigger sequences, elements that are indispensable for coiled-coil formation. By using the archetype coiled-coil domain of the yeast transcriptional activator GCN4 as a model system, we show that well-established trimer-specific oligomerization-state determinants switch the peptide's topology from a dimer to a trimer only when inserted into the trigger sequence. We successfully confirmed our results in two other, unrelated coiled-coil dimers, ATF1 and cortexillin-1. We furthermore show that multiple topology determinants can coexist in the same trigger sequence, revealing a delicate balance of the resulting oligomerization state by position-dependent forces. Our experimental results should significantly improve the prediction of the oligomerization state of coiled coils. They therefore should have major implications for the rational design of coiled coils and consequently many applications using these popular oligomerization domains.

  2. Monitoring ground-surface heating during expansion of the Casa Diablo production well field at Mammoth Lakes, California

    Science.gov (United States)

    Bergfeld, D.; Vaughan, R. Greg; Evans, William C.; Olsen, Eric

    2015-01-01

    The Long Valley hydrothermal system supports geothermal power production from 3 binary plants (Casa Diablo) near the town of Mammoth Lakes, California. Development and growth of thermal ground at sites west of Casa Diablo have created concerns over planned expansion of a new well field and the associated increases in geothermal fluid production. To ensure that all areas of ground heating are identified prior to new geothermal development, we obtained high-resolution aerial thermal infrared imagery across the region. The imagery covers the existing and proposed well fields and part of the town of Mammoth Lakes. Imagery results from a predawn flight on Oct. 9, 2014 readily identified the Shady Rest thermal area (SRST), one of two large areas of ground heating west of Casa Diablo, as well as other known thermal areas smaller in size. Maximum surface temperatures at 3 thermal areas were 26–28 °C. Numerous small areas with ground temperatures >16 °C were also identified and slated for field investigations in summer 2015. Some thermal anomalies in the town of Mammoth Lakes clearly reflect human activity.Previously established projects to monitor impacts from geothermal power production include yearly surveys of soil temperatures and diffuse CO2 emissions at SRST, and less regular surveys to collect samples from fumaroles and gas vents across the region. Soil temperatures at 20 cm depth at SRST are well correlated with diffuse CO2 flux, and both parameters show little variation during the 2011–14 field surveys. Maximum temperatures were between 55–67 °C and associated CO2 discharge was around 12–18 tonnes per day. The carbon isotope composition of CO2 is fairly uniform across the area ranging between –3.7 to –4.4 ‰. The gas composition of the Shady Rest fumarole however has varied with time, and H2S concentrations in the gas have been increasing since 2009.

  3. Satellite and Ground-Based Sensors for the Urban Heat Island Analysis in the City of Rome

    Directory of Open Access Journals (Sweden)

    Roberto Fabrizi

    2010-05-01

    Full Text Available In this work, the trend of the Urban Heat Island (UHI of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging to the layer of air closest to the surface. UHI spatial characteristics have been assessed using air temperatures measured by both weather stations and brightness temperature maps from the Advanced Along Track Scanning Radiometer (AATSR on board ENVISAT polar-orbiting satellite. In total, 634 daytime and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI during summer months reveals a mean growth in magnitude of 3–4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations.

  4. TEXT poloidal coil systems power supplies

    International Nuclear Information System (INIS)

    Hutchins, S.H.; Brower, D.F.

    1977-01-01

    TEXT is a convertional iron core tokamak which will have a toroidal field of 3.0 Tesla produced by room temperature copper coils and a maximum plasma current pulse of 400 kA induced by a 40 turn Ohmic Heating coil. The major radius is 100 cm and the minor radius of the plasma is 28 cm. The machine is intended for basic research in tokamak plasma physics and atomic physics and is designed primarily to provide a stable hot plasma, extremely good diagnostic access, and reliable operation. The discharge pulse length will be 300 msec and the repetition period 120 seconds. Power for the toroidal field coils and for the ohmic heating supply is provided by a 100 MVA energy storage alternator. The vertical field, horizontal field, fast positioning, and discharge cleaning power supply systems are powered from the Tokamak Laboratory power mains. The ohmic heating power system consists of an SCR controlled premagnetizing supply and commutation circuit, the main ohmic heating capacitor bank to provide plasma breakdown and current rise, and an SCR controlled power supply which sustains plasma current during the 300 ms pulse. The vertical field power system uses a small capacitor bank and an SCR controlled supply. The horizontal field has a reversible SCR controlled supply, and the fast positioning coils are powered by bipolar output transistor controlled supplies. This paper describes the loads, required wave forms, and the specifications for these power supply systems

  5. Commercial applications for COIL

    Science.gov (United States)

    Solomon, Wayne C.; Carroll, David L.; King, D. M.; Fockler, L. A.; Stromberg, D. S.; Sexauer, M.; Milmoe, A.; Sentman, Lee H.

    2000-01-01

    The chemical oxygen-iodine laser (COIL) is a high power, fiber deliverable tool, which can be used for a number of different industrial applications. COIL is of particular interest because of its short fiber deliverable wavelength, high scaleable continuous wave power, and excellent material interaction properties. In past research the University of Illinois at Urbana-Champaign identified and decommissioning and decontamination (DD) of nuclear facilities as a primary focus for COIL technology. DD will be a major challenge in the coming decades. The use of a robotically driven fiber delivered cutting/ablation tool in contaminated areas promises to lower risks to workers for the DD mission. Further, the high cutting speed of COIL will significantly reduce the time required to cut contaminated equipment, reducing costs. The high power of COIL will permit the dismantling of thick stacks of piping and equipment as well as reactor vessels. COIL is very promising for the removal of material from contaminated surfaces, perhaps to depths thicker than an inch. Laser cutting and ablation minimizes dust and fumes, which reduces the required number of high efficiency particulate accumulator filters, thus reducing costly waste disposal. Other potential industrial applications for COIL are shipbuilding, automotive manufacturing, heavy machinery manufacturing, tasks requiring underwater cutting or welding, and there appear to be very promising applications for high powers lasers in the oil industry.

  6. Open coil traction system.

    Science.gov (United States)

    Vibhute, Pavankumar Janardan

    2012-01-01

    Sliding mechanics have become a popular method for space closure, with the development of preadjusted edgewise appliances. Furthermore, various space closing auxiliaries have been developed and extensively evaluated for their clinical efficiency. Their effectiveness is enhanced with optimum force magnitude and low load deflection rate/force decay. With the advent of nickel-titanium (Ni-Ti) springs in orthodontics, load deflection rates have been markedly reduced. To use Ni-Ti springs, clinicians have to depend upon prefabricated closed coil springs. The open coil traction system, or open coil retraction spring, is developed utilizing Ni-Ti open coil springs for orthodontic space closure. This article describes the fabrication and clinical application of the open coil traction system, which has a number of advantages. It sustains a low load deflection rate with optimum force magnitude, and its design is adjustable for a desired length and force level. It is fail-safe for both activation and deactivation (ie, it cannot be overactivated, and the decompression limit of the open coil is controlled by the operator). The open coil traction system can be offset from the mucosa to help reduce soft tissue impingement.

  7. An Environmental and Economic Assessment for Selecting the Optimal Ground Heat Exchanger by Considering the Entering Water Temperature

    Directory of Open Access Journals (Sweden)

    Jimin Kim

    2015-07-01

    Full Text Available In order to solve environmental problems such as global warming and resource depletion in the construction industry, interest in new renewable energy (NRE systems has increased. The ground source heat pump (GSHP system is the most efficient system among NRE systems. However, since the initial investment cost of the GSHP is quite expensive, a feasibility study needs to be conducted from the life-cycle perspective. Meanwhile, the efficiency of GSHP depends most significantly on the entering water temperature (EWT of the ground heat exchanger (GHE. Therefore, this study aims to assess the environmental and economic effects of the use of GHE for selecting the optimal GHE. This study was conducted in three steps: (i establishing the basic information and selecting key factors affecting GHE performances; (ii making possible alternatives of the GHE installation by considering EWT; and (iii using life-cycle assessment and life-cycle cost, as well as comprehensive evaluation of the environmental and economic effects on the GHE. These techniques allow for easy and accurate determination of the optimal design of the GHE from the environmental and economic effects in the early design phase. In future research, a multi-objective decision support model for the GSHP will be developed.

  8. Studies on the under ground heating in greenhouse. Measuring of thermal conductivity of soil

    Energy Technology Data Exchange (ETDEWEB)

    Iwao, Toshio; Takeyama, Koichi

    1987-12-21

    The underground heating system is an effective method of heating a greenhouse, because the system controls directly the temperature of soil near the roots. The thermal conductivity of soil was measured by the steady-state method, and the heat transfer characteristics in soil were examined in this study. In measuring the thermal conductivity through experiments, firstly the thermal conductivity of a reference plate was measured by the steady-state method, then on the basis of the above mentioned result, the thermal conuctivity of soil was obtained by the comparative method. Toyoura standard sands with particle size of 0.21-0.25mm were used as the sample. As the experiment result, the relations between the thermal conductivity of the reference plate (glass) and temperature was made clear, furthermore through the measurements using these relations, it was clarified that the apparent thermal conductivity is influenced by soil water content. It seems that the difference between the apparent thermal conductivity and the real one is caused mainly by a migration of latent heat with a migration of steam. (10 figs, 7 refs)

  9. Field Demonstration of Ground-Source Integrated Heat Pump - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gehl, Anthony C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    Reducing energy consumption in buildings is key to reducing or limiting the negative environmental impacts from the building sector. According to the United States (U.S.) Energy Information Administration (EIA), in 2013, commercial buildings consumed 18.1 quads of primary energy, which was 18.6% of the total U.S. primary energy consumption. The primary energy consumption in the commercial sector is projected to increase by 2.8 quads from 2013 to 2040, the second largest increase after the industrial sector. Further space heating, space cooling, and ventilation (HVAC) services accounted for 31% of the energy consumption in commercial buildings. The technical objective of this project is to demonstrate the capability of the new GS-IHP system to reduce overall energy use for space heating, space cooling, and water heating by at least 45% vs. a conventional electric RTU and electric WH in a light commercial building application. This project supports the DOE-Building Technologies Office (BTO) goals of reducing HVAC energy use by 20% and water heating by 60% by 2030.

  10. Coil spring venting arrangement

    International Nuclear Information System (INIS)

    McCugh, R.M.

    1975-01-01

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed

  11. Structural analysis of the NET toroidal field coils and conductor

    International Nuclear Information System (INIS)

    Mitchell, N.; Collier, D.; Gori, R.

    1989-01-01

    The NET toroidal field coils will utilise A15-type superconductor at 4.2 K to generate fields up to 11.5 T. The superconductor strands themselves are sensitive to strain, which causes degradation of their current carrying capacity, and thus the detailed behaviour of the coil conductor must be analysied so that the strian can be minimised. This analysis must include the manufacturing processes of the conductor as well as the normal and abnormal loperational loads. The conductor will be insulated and bonded by glass fibre reinforced epoxy resin, with limited bonding shear strength, and the overall support of the complete coil system must be designed to reduce these shear stresses. The coils will be subjected to pulse loads form the poloidal field coils, and analysis of the slip between the various coil components, such as conductors and the coil case, giving rise to frictional heating and possible loss of superconducting properties is another important factor, which has been investigated by a number of stress analyses. The manufacturing, thermal and normal magnetic loads on the coils and the analysis leading to the proposed structural design are described. In addition to the normal operating conditions, there is a range of abnormal load conditions which could result from electrical or mechanical faults on the coils. The effect of these potential faults has been analysed and the coil design modified to prevent catastrophic structural failure. (author). 13 refs.; 8 figs.; 1 tab

  12. Extending the self-assembly of coiled-coil hybrids

    NARCIS (Netherlands)

    Robson Marsden, Hana

    2009-01-01

    Of the various biomolecular building blocks in use in nature, coiled-coil forming peptides are amongst those with the most potential as building blocks for the synthetic self-assembly of nanostructures. Native coiled coils have the ability to function in, and influence, complex systems composed of

  13. First assembly phase for the ATLAS toroid coils

    CERN Document Server

    Patrice Loïez

    2003-01-01

    The ATLAS barrel toroid system consists of eight coils, each of axial length 25.3 m, assembled radially and symmetrically around the beam axis. The coils are of a flat racetrack type with two double-pancake windings made of 20.5 kA aluminium-stabilized niobium-titanium superconductor. In the first phase of assembly, the two 'pancakes' are packed into their vacuum vessel. This is done using bladders filled with resin and glass microbeads under pressure. The resin is heated and, once cooled, holds the pancakes in place. The operation has to be performed on both sides of the coil, which necessitated a special technique to turn the coils over and then transport them to the heating table. Photos 01, 02, 03: Use of the overhead travelling crane to hoist the coil up and then tilt it over, the coil frame's metal feet being used as rotational pivots, supporting half the coil's weight. Once it has been turned over, the coil, now with only half the frame, is transported to the heating table using a special lifting gant...

  14. A periodic table of coiled-coil protein structures.

    Science.gov (United States)

    Moutevelis, Efrosini; Woolfson, Derek N

    2009-01-23

    Coiled coils are protein structure domains with two or more alpha-helices packed together via interlacing of side chains known as knob-into-hole packing. We analysed and classified a large set of coiled-coil structures using a combination of automated and manual methods. This led to a systematic classification that we termed a "periodic table of coiled coils," which we have made available at http://coiledcoils.chm.bris.ac.uk/ccplus/search/periodic_table. In this table, coiled-coil assemblies are arranged in columns with increasing numbers of alpha-helices and in rows of increased complexity. The table provides a framework for understanding possibilities in and limits on coiled-coil structures and a basis for future prediction, engineering and design studies.

  15. Quantifying the energy impact of a variable flow pump in a ground-coupled heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Iolova, K.; Bernier, M.A. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Mecanique; Nichols, L. [Dessau-Soprin, Montreal, PQ (Canada)

    2006-07-01

    The thermal behaviour of an energy-efficient public high school building was modelled using the TRNSYS multi-zone building simulation program. The architectural elements such as windows, external and internal walls, roofs, and slabs were described in detail. The two-storey Ecole du Tournant high school near Montreal is the most efficient in Quebec and the second in Canada. It consumes 79.2 per cent less source energy than a typical high school built in accordance with the Model National Energy Code of Canada for Buildings. This presentation described the case study and quantified the energy impact of replacing a constant speed pump with a pump driven by a variable frequency drive in a ground-coupled heat pump (GCHP) system that was installed in the high school. Performance data collected from an on-site energy management system showed that the annual energy consumption of the heat pumps is 33 per cent (63700 kWh) of the total energy consumption of the school while the circulating pump consumes 7.1 per cent (13702 kWh). This performance data was used to validate the energy simulations which were performed using TRNSYS 15. Simulations with variable-flow pumping showed that pumping energy consumption was reduced by about 82 per cent while the total energy used by the circulating pump and heat pumps was reduced by 18.5 per cent. 11 refs., 2 tabs., 13 figs.

  16. LHC bending magnet coil

    CERN Multimedia

    A short test version of coil of wire used for the LHC dipole magnets. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. Magnet coils are made of copper-clad niobium–titanium cables — each wire in the cable consists of 9’000 niobium–titanium filaments ten times finer than a hair.

  17. Borehole induction coil transmitter

    Science.gov (United States)

    Holladay, Gale; Wilt, Michael J.

    2002-01-01

    A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

  18. Temperature distributions in pavement and bridge slabs heated by using vertical ground-source heat pump systems - doi: 10.4025/actascitechnol.v35i4.15712

    Directory of Open Access Journals (Sweden)

    Asım Balbay

    2013-10-01

    Full Text Available Temperature distribution which occurs in pavement and bridge slabs heated for de-icing and snow melting during cold periods is determined by using vertical ground-source heat pump (GSHP systems with U-tube ground heat exchanger (GHE. The bridge and pavement models (slabs for de-icing and snow melting were constructed. A three-dimensional finite element model (FEM was developed to simulate temperature distribution of bridge slab (BS and pavement slab (PS. The temperature distribution simulations of PS and BS were conducted numerically by computational fluid dynamics (CFD program named ‘Fluent’. Congruence between the simulations and experimental data was determined.   

  19. Thermal performance in circular tube fitted with coiled square wires

    International Nuclear Information System (INIS)

    Promvonge, Pongjet

    2008-01-01

    The effects of wires with square cross section forming a coil used as a turbulator on the heat transfer and turbulent flow friction characteristics in a uniform heat flux, circular tube are experimentally investigated in the present work. The experiments are performed for flows with Reynolds numbers ranging from 5000 to 25,000. Two different spring coiled wire pitches are introduced. The results are also compared with those obtained from using a typical coiled circular wire, apart from the smooth tube. The experimental results reveal that the use of coiled square wire turbulators leads to a considerable increase in heat transfer and friction loss over those of a smooth wall tube. The Nusselt number increases with the rise of Reynolds number and the reduction of pitch for both circular and square wire coils. The coiled square wire provides higher heat transfer than the circular one under the same conditions. Also, performance evaluation criteria to assess the real benefits in using both coil wires of the enhanced tube are determined

  20. On modular stellarator reactor coils

    International Nuclear Information System (INIS)

    Rau, F.; Harmeyer, E.; Kisslinger, J.; Wobig, H.

    1985-01-01

    Modular twisted coils are discussed which produce magnetic fields of the Advanced Stellarator WENDELSTEIN VII-AS type. Reducing the number coils/FP offers advantage for maintenance of coils, but increases the magnetic ripple and B m /B o . Computation of force densities within the coils of ASR and ASB yield local maximum values of about 80 and 180 MN/m 3 , respectively. A system of mutual coil support is being developed. Twisted coils in helical arrangement provide a reactor-sized HELIAC system. In order to reduce the magnetic ripple, a large number of 14 coils/FP in special arrangement is used

  1. TFTR toroidal field coil design

    International Nuclear Information System (INIS)

    Smith, G.E.; Punchard, W.F.B.

    1977-01-01

    The design of the Tokamak Fusion Test Reactor (TFTR) Toroidal Field (TF) magnetic coils is described. The TF coil is a 44-turn, spiral-wound, two-pancake, water-cooled configuration which, at a coil current of 73.3 kiloamperes, produces a 5.2-Tesla field at a major radius of 2.48 meters. The magnetic coils are installed in titanium cases, which transmit the loads generated in the coils to the adjacent supporting structure. The TFTR utilizes 20 of these coils, positioned radially at 18 0 intervals, to provide the required toroidal field. Because it is very highly loaded and subject to tight volume constraints within the machine, the coil presents unique design problems. The TF coil requirements are summarized, the coil configuration is described, and the problems highlighted which have been encountered thus far in the coil design effort, together with the development tests which have been undertaken to verify the design

  2. NCSX Toroidal Field Coil Design

    International Nuclear Information System (INIS)

    Kalish M; Rushinski J; Myatt L; Brooks A; Dahlgren F; Chrzanowski J; Reiersen W; Freudenberg K.

    2005-01-01

    The National Compact Stellarator Experiment (NCSX) is an experimental device whose design and construction is underway at the Department of Energy's Princeton Plasma Physics Laboratory (PPPL). The primary coil systems for the NCSX device consist of the twisted plasma-shaping Modular Coils, the Poloidal Field Coils, and the Toroidal Field (TF) Coils. The TF Coils are D-shaped coils wound from hollow copper conductor, and vacuum impregnated with a glass-epoxy resin system. There are 18 identical, equally spaced TF coils providing 1/R field at the plasma. They operate within a cryostat, and are cooled by LN2, nominally, to 80K. Wedge shaped castings are assembled to the inboard face of these coils, so that inward radial loads are reacted via the nesting of each of the coils against their adjacent partners. This paper outlines the TF Coil design methodology, reviews the analysis results, and summarizes how the design and analysis support the design requirements

  3. Case Study for the ARRA-funded Ground Source Heat Pump Demonstration at Denver Museum of Nature & Science

    Energy Technology Data Exchange (ETDEWEB)

    Im, Piljae [ORNL; Liu, Xiaobing [ORNL

    2016-09-01

    High initial costs and lack of public awareness of ground-source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy-saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects were competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This report highlights the findings of a case study of one such GSHP demonstration projects that uses a recycled water heat pump (RWHP) system installed at the Denver Museum of Nature & Science in Denver, Colorado. The RWHP system uses recycled water from the city’s water system as the heat sink and source for a modular water-to-water heat pump (WWHP). This case study was conducted based on the available measured performance data from December 2014 through August 2015, utility bills of the building in 2014 and 2015, construction drawings, maintenance records, personal communications, and construction costs. The annual energy consumption of the RWHP system was calculated based on the available measured data and other related information. It was compared with the performance of a baseline scenario— a conventional VAV system using a water-cooled chiller and a natural gas fired boiler, both of which have the minimum energy efficiencies allowed by ASHRAE 90.1-2010. The comparison was made to determine energy savings, operating cost savings, and CO2 emission reductions achieved by the RWHP system. A cost analysis was performed to evaluate the simple payback of the RWHP system. Summarized below are the results of the performance analysis, the learned lessons, and recommended improvement in the operation of the RWHP system.

  4. Coil protection calculator for TFTR

    International Nuclear Information System (INIS)

    Marsala, R.J.; Woolley, R.D.

    1987-01-01

    A new coil protection calculator (CPC) is presented in this paper. It is now being developed for TFTR's magnetic field coils will replace the existing coil fault detector. The existing fault detector sacrifices TFTR operating capability for simplicity. The new CPC will permit operation up to the actual coil limits by accurately and continuously computing coil parameters in real-time. The improvement will allow TFTR to operate with higher plasma currents and will permit the optimization of pulse repetition rates

  5. The Strategic Exercise of Options Using Government Subsidies: An Analysis of Production Subsidies for the Ground Source Heat Pump

    Science.gov (United States)

    Lin, Sheng-Hau; Li, Jia-Hsun; Hsu, Chih-Chen; Hsieh, Jing-Chzi; Liao, Pin-Chao

    2018-04-01

    This study utilizes consolidation investment theory to incorporate with business strategies and government subsidy to develop a strategic exercise of options model. This empirical investigation examines the ground source heat pump (GSHP) government subsidy program, which is part of China’s 12th Five Year Plan. The developed model is applied to explain the behaviours of business investment with regard to strategic investment timing, option values, and the influence of government subsidies in duopolistic real-world investment decisions. The results indicate that subsidy policy can reduce the differences of investment timing among GSHP investors and has clearly evidenced the positive benefit–cost ratio of government subsidy, which facilitates China’s GSHP industry development.

  6. Technical Feasibility Study for Deployment of Ground-Source Heat Pump Systems: Portsmouth Naval Shipyard -- Kittery, Maine

    Energy Technology Data Exchange (ETDEWEB)

    Hillesheim, M.; Mosey, G.

    2014-11-01

    The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response, in accordance with the RE-Powering America's Lands initiative, engaged the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to conduct feasibility studies to assess the viability of developing renewable energy generating facilities on contaminated sites. Portsmouth Naval Shipyard (PNSY) is a United States Navy facility located on a series of conjoined islands in the Piscataqua River between Kittery, ME and Portsmouth, NH. EPA engaged NREL to conduct a study to determine technical feasibility of deploying ground-source heat pump systems to help PNSY achieve energy reduction goals.

  7. 地源热泵与太阳能联合供热系统集热器面积优化的研究%Collector Area Optimization of Ground Source Heat Pump and Solar Combined Heating System

    Institute of Scientific and Technical Information of China (English)

    智超英; 赵宇含

    2018-01-01

    This paper mainly analyzes various influence factors on heat collector area of the ground source heat pump and solar combined heating system, studies the relationship of the cost of solar heat collection system,ground source heat pump operating costs per square meter,the maximum net benefit and solar collector area. In one run cycle,considering the maximum income,solar heating guarantee rate and ground source heat pump operating costs per square meter, the collector area of the combined heating system is optimized finally.%分析影响地源热泵与太阳能联合供热系统集热器面积的各种因素,研究太阳能集热系统造价、地源热泵每平方米运行费用、最大净受益、太阳能集热器面积相互间的关系.在一个循环周期内参考最大净收益,利用太阳能采暖保证率和地源热泵每平方米的运行费用的统计数据,最终联合供热系统的集热器面积达到最优.

  8. Exergy analysis of a two-stage ground source heat pump with a vertical bore for residential space conditioning under simulated occupancy

    International Nuclear Information System (INIS)

    Ally, Moonis R.; Munk, Jeffrey D.; Baxter, Van D.; Gehl, Anthony C.

    2015-01-01

    Highlights: • Exergy and energy analysis of a vertical-bore ground source heat pump over a 12-month period is presented. • The ground provided more than 75% of the heating energy. • Performance metrics are presented. • Sources of systemic inefficiency are identified and prioritized using Exergy analysis. • Understanding performance metrics is vital for judicial use of renewable energy. - Abstract: This twelve-month field study analyzes the performance of a 7.56 W (2.16-ton) water-to-air-ground source heat pump (WA-GSHP) to satisfy domestic space conditioning loads in a 253 m 2 house in a mixed-humid climate in the United States. The practical feasibility of using the ground as a source of renewable energy is clearly demonstrated. Better than 75% of the energy needed for space heating was extracted from the ground. The average monthly electricity consumption for space conditioning was only 40 kW h at summer and winter thermostat set points of 24.4 °C and 21.7 °C, respectively. The WA-GSHP shared the same 94.5 m vertical bore ground loop with a separate water-to-water ground-source heat pump (WW-GSHP) for meeting domestic hot water needs in the same house. Sources of systemic irreversibility, the main cause of lost work, are identified using Exergy and energy analysis. Quantifying the sources of Exergy and energy losses is essential for further systemic improvements. The research findings suggest that the WA-GSHPs are a practical and viable technology to reduce primary energy consumption and greenhouse gas emissions under the IECC 2012 Standard, as well as the European Union (EU) 2020 targets of using renewable energy resources

  9. On sustainable and efficient design of ground-source heat pump systems

    Science.gov (United States)

    Grassi, W.; Conti, P.; Schito, E.; Testi, D.

    2015-11-01

    This paper is mainly aimed at stressing some fundamental features of the GSHP design and is based on a broad research we are performing at the University of Pisa. In particular, we focus the discussion on an environmentally sustainable approach, based on performance optimization during the entire operational life. The proposed methodology aims at investigating design and management strategies to find the optimal level of exploitation of the ground source and refer to other technical means to cover the remaining energy requirements and modulate the power peaks. The method is holistic, considering the system as a whole, rather than focusing only on some components, usually considered as the most important ones. Each subsystem is modeled and coupled to the others in a full set of equations, which is used within an optimization routine to reproduce the operative performances of the overall GSHP system. As a matter of fact, the recommended methodology is a 4-in-1 activity, including sizing of components, lifecycle performance evaluation, optimization process, and feasibility analysis. The paper reviews also some previous works concerning possible applications of the proposed methodology. In conclusion, we describe undergoing research activities and objectives of future works.

  10. Development and Experimental Validation of a TRNSYS Dynamic Tool for Design and Energy Optimization of Ground Source Heat Pump Systems

    Directory of Open Access Journals (Sweden)

    Félix Ruiz-Calvo

    2017-09-01

    Full Text Available Ground source heat pump (GSHP systems stand for an efficient technology for renewable heating and cooling in buildings. To optimize not only the design but also the operation of the system, a complete dynamic model becomes a highly useful tool, since it allows testing any design modifications and different optimization strategies without actually implementing them at the experimental facility. Usually, this type of systems presents strong dynamic operating conditions. Therefore, the model should be able to predict not only the steady-state behavior of the system but also the short-term response. This paper presents a complete GSHP system model based on an experimental facility, located at Universitat Politècnica de València. The installation was constructed in the framework of a European collaborative project with title GeoCool. The model, developed in TRNSYS, has been validated against experimental data, and it accurately predicts both the short- and long-term behavior of the system.

  11. The contribution of geology and groundwater studies to city-scale ground heat network strategies: A case study from Cardiff, UK

    Science.gov (United States)

    Boon, David; Farr, Gareth; Patton, Ashley; Kendall, Rhian; James, Laura; Abesser, Corinna; Busby, Jonathan; Schofield, David; White, Debbie; Gooddy, Daren; James, David; Williams, Bernie; Tucker, David; Knowles, Steve; Harcombe, Gareth

    2016-04-01

    The development of integrated heat network strategies involving exploitation of the shallow subsurface requires knowledge of ground conditions at the feasibility stage, and throughout the life of the system. We describe an approach to the assessment of ground constraints and energy opportunities in data-rich urban areas. Geological and hydrogeological investigations have formed a core component of the strategy development for sustainable thermal use of the subsurface in Cardiff, UK. We present findings from a 12 month project titled 'Ground Heat Network at a City Scale', which was co-funded by NERC/BGS and the UK Government through the InnovateUK Energy Catalyst grant in 2015-16. The project examined the technical feasibility of extracting low grade waste heat from a shallow gravel aquifer using a cluster of open loop ground source heat pumps. Heat demand mapping was carried out separately. The ground condition assessment approach involved the following steps: (1) city-wide baseline groundwater temperature mapping in 2014 with seasonal monitoring for at least 12 months prior to heat pump installation (Patton et al 2015); (2) desk top and field-based investigation of the aquifer system to determine groundwater levels, likely flow directions, sustainable pumping yields, water chemistry, and boundary conditions; (3) creation of a 3D geological framework model with physical property testing and model attribution; (4) use steps 1-3 to develop conceptual ground models and production of maps and GIS data layers to support scenario planning, and initial heat network concept designs; (5) heat flow modelling in FEFLOW software to analyse sustainability and predict potential thermal breakthrough in higher risk areas; (6) installation of a shallow open loop GSHP research observatory with real-time monitoring of groundwater bodies to provide data for heat flow model validation and feedback for system control. In conclusion, early ground condition modelling and subsurface

  12. Quench detector for large pulsed coils and quench analysis for the LASL/Westinghouse 20 MJ coil

    International Nuclear Information System (INIS)

    Hennessy, M.J.; Heintz, A.W.; Eckels, P.W.

    1981-01-01

    A detection scheme has been devised for use in the test of the 20 Mj Induction Heating Coil. This scheme allows the sensing of plus or minus voltages less than 320 mv resistive in magnitude in coils which will have inductive voltage components as high as /plus or minus/2.5 kv. The network which achieves this sensitivity is stable to less than 12.8 ppm. This method adopted involves the bucking out of the inductive voltage with two secondary co-wound flux sensing coils tapped at locations adjacent to voltage taps in the main superconducting coil. The detection scheme is recommended if large ripple or control voltages exist subsequent to the coil pulse. The most severe event which might quench the coil and/or damage the winding is exposure of the coil to gaseous cooling through lack of proper liquid level control. The detection scheme will protect the coil against this and other abnormal conditions that could damage the coil

  13. Heat pipe heat storage performance

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, A; Pasquetti, R [Univ. de Provence, Marseille (FR). Inst. Universitaire des Systemes; Grakovich, L P; Vasiliev, L L [A.V. Luikov Heat and Mass Transfer Inst. of the BSSR, Academy of Sciences, Minsk (BY)

    1989-01-01

    Heat storage offers essential thermal energy saving for heating. A ground heat store equipped with heat pipes connecting it with a heat source and to the user is considered in this paper. It has been shown that such a heat exchanging system along with a batch energy source meets, to a considerable extent, house heating requirements. (author).

  14. Superconducting coil protection

    International Nuclear Information System (INIS)

    Woods, E.L.

    1975-01-01

    The protection system is based on a two-phase construction program. Phase I is the development of a reliable hardwired relay control system with a digital loop utilizing firmware and a microprocessor controller. Phase II is an expansion of the digital loop to include many heretofore unmonitored coil variables. These new monitored variables will be utilized to establish early quench detection and to formulate confirmation techniques of the quench detection mechanism. Established quench detection methods are discussed and a new approach to quench detection is presented. The new circuit is insensitive to external pulsed magnetic fields and the associated induced voltages. Reliability aspects of the coil protection system are discussed with respect to shutdowns of superconducting coil systems. Redundance and digital system methods are presented as related topics

  15. 太阳能耦合地源热泵供暖系统的实验研究%Experimental Study on Heating System of Solar Coupled Ground Source Heat Pump

    Institute of Scientific and Technical Information of China (English)

    智超英; 赵宇含

    2017-01-01

    太阳能耦合地源热泵系统的设计以太阳能为辅助、地源热泵为主,最大化地利用太阳能资源,在满足地板采暖制备的情况下,富裕的热量可以补充到生活用水当中.通过实验验证了太阳能耦合地源热泵供暖系统可以有效恢复土壤温度,提高机组性能系数,实现热泵长期稳定的运行.%The design of solar coupled ground source heat pump system is based on solar energy and ground source heat pump.The system can maximize solar energy utilization in the preparation of floor heating.Rich heat can be added to the life water.This paper introduces the solar coupled ground source heat pump heating system.The experiment proves that the system can effectively restore the soil temperature, improve the performance coefficient of the crew, and realize the long-term stable operation of the heat pump.

  16. Land subsidence due to groundwater pumping and recharge: considering the particle-deposition effect in ground-source heat-pump engineering

    Science.gov (United States)

    Cui, Xianze; Liu, Quansheng; Zhang, Chengyuan; Huang, Yisheng; Fan, Yong; Wang, Hongxing

    2018-01-01

    With the rapid development and use of ground-source heat-pump (GSHP) systems in China, it has become imperative to research the effects of associated long-term pumping and recharge processes on ground deformation. During groundwater GSHP operation, small particles can be transported and deposited, or they can become detached in the grain skeleton and undergo recombination, possibly causing a change in the ground structure and characteristics. This paper presents a mathematical ground-deformation model that considers particle transportation and deposition in porous media based on the geological characteristics of a dual-structure stratum in Wuhan, eastern China. Thermal effects were taken into consideration because the GSHP technology used involves a device that uses heat from a shallow layer of the ground. The results reveal that particle deposition during the long-term pumping and recharge process has had an impact on ground deformation that has significantly increased over time. In addition, there is a strong correlation between the deformation change (%) and the amount of particle deposition. The position of the maximum deformation change is also the location where most of the particles are deposited, with the deformation change being as high as 43.3%. The analyses also show that flow of groundwater can have an effect on the ground deformation process, but the effect is very weak.

  17. Land subsidence due to groundwater pumping and recharge: considering the particle-deposition effect in ground-source heat-pump engineering

    Science.gov (United States)

    Cui, Xianze; Liu, Quansheng; Zhang, Chengyuan; Huang, Yisheng; Fan, Yong; Wang, Hongxing

    2018-05-01

    With the rapid development and use of ground-source heat-pump (GSHP) systems in China, it has become imperative to research the effects of associated long-term pumping and recharge processes on ground deformation. During groundwater GSHP operation, small particles can be transported and deposited, or they can become detached in the grain skeleton and undergo recombination, possibly causing a change in the ground structure and characteristics. This paper presents a mathematical ground-deformation model that considers particle transportation and deposition in porous media based on the geological characteristics of a dual-structure stratum in Wuhan, eastern China. Thermal effects were taken into consideration because the GSHP technology used involves a device that uses heat from a shallow layer of the ground. The results reveal that particle deposition during the long-term pumping and recharge process has had an impact on ground deformation that has significantly increased over time. In addition, there is a strong correlation between the deformation change (%) and the amount of particle deposition. The position of the maximum deformation change is also the location where most of the particles are deposited, with the deformation change being as high as 43.3%. The analyses also show that flow of groundwater can have an effect on the ground deformation process, but the effect is very weak.

  18. Pressure rise analysis in superconducting coils during dumping

    International Nuclear Information System (INIS)

    Tada, E.; Shimamoto, S.

    1984-01-01

    This chapter describes the ALPHE computer code, whose purpose is to calculate transient helium behavior in a poolboiling coil and to determine suitable characteristics of safety devices to minimize the maximum pressure and the liquid helium lost during dumping due to quench, or when discharging without normalcy. The analysis is compared with the measurements obtained in the domestic test of the Japanese LCT coil. Topics considered include basic equations (helium behavior, heat generation), manual dump without quench, and dumping due to quench. It is demonstrated that the transient behavior, calculated by ALPHE assuming quasi-static equilibrium between helium and coil, is in good agreement with the experimental measurements observed in the domestic test of the Japanese LCT coil. The engineering technique required for the design criteria of superconducting coils and safety device during dumping is established. ALPHE can be used to design an emergency safety system for a helium refrigerator during dumping

  19. High voltage investigations for ITER coils

    International Nuclear Information System (INIS)

    Fink, S.; Fietz, W.H.

    2006-01-01

    The superconducting ITER magnets will be excited with high voltage during operation and fast discharge. Because the coils are complex systems the internal voltage distribution can differ to a large extent from the ideal linear voltage distribution. In case of fast excitations internal voltages between conductor and radial plate of a TF coil can be even higher than the terminal voltage of 3.5 kV to ground which appears during a fast discharge without a fault. Hence the determination of the transient voltage distribution is important for a proper insulation co-ordination and will provide a necessary basis for the verification of the individual insulation design and the choice of test voltages and waveforms. Especially the extent of internal overvoltages in case of failures, e. g. malfunction of discharge units and / or arcing is of special interest. Transient calculations for the ITER TF coil system have been performed for fast discharge and fault scenarios to define test voltages for ITER TF. The conductor and radial plate insulation of the ITER TF Model Coil were exposed at room temperature to test voltages derived from the results from these calculations. Breakdown appeared during the highest AC voltage step. A fault scenario for the TF fast discharge system is presented where one fault triggers a second fault, leading to considerable voltage stress. In addition a FEM model of Poloidal Field Coil 3 for the determination of the parameters of a detailed network model is presented in order to prepare detailed investigations of the transient voltage behaviour of the PF coils. (author)

  20. NET model coil test possibilities

    International Nuclear Information System (INIS)

    Erb, J.; Gruenhagen, A.; Herz, W.; Jentzsch, K.; Komarek, P.; Lotz, E.; Malang, S.; Maurer, W.; Noether, G.; Ulbricht, A.; Vogt, A.; Zahn, G.; Horvath, I.; Kwasnitza, K.; Marinucci, C.; Pasztor, G.; Sborchia, C.; Weymuth, P.; Peters, A.; Roeterdink, A.

    1987-11-01

    A single full size coil for NET/INTOR represents an investment of the order of 40 MUC (Million Unit Costs). Before such an amount of money or even more for the 16 TF coils is invested as much risks as possible must be eliminated by a comprehensive development programme. In the course of such a programme a coil technology verification test should finally prove the feasibility of NET/INTOR TF coils. This study report is almost exclusively dealing with such a verification test by model coil testing. These coils will be built out of two Nb 3 Sn-conductors based on two concepts already under development and investigation. Two possible coil arrangements are discussed: A cluster facility, where two model coils out of the two Nb 3 TF-conductors are used, and the already tested LCT-coils producing a background field. A solenoid arrangement, where in addition to the two TF model coils another model coil out of a PF-conductor for the central PF-coils of NET/INTOR is used instead of LCT background coils. Technical advantages and disadvantages are worked out in order to compare and judge both facilities. Costs estimates and the time schedules broaden the base for a decision about the realisation of such a facility. (orig.) [de

  1. Fault Analysis of ITER Coil Power Supply System

    International Nuclear Information System (INIS)

    Song, In Ho; Jun, Tao; Benfatto, Ivone

    2009-01-01

    The ITER magnet coils are all designed using superconductors with high current carrying capability. The Toroidal Field (TF) coils operate in a steadystate mode with a current of 68 kA and discharge the stored energy in case of quench with using 9 interleaved Fast Discharge Units (FDUs). The Central Solenoid (CS) coils and Poloidal Field (PF) coils operate in a pulse mode with currents of up to 45 kA and require fast variation of currents inducing more than 10 kV during normal operation on the coil terminals using Switching Network (SN) systems (CSs, PF1 and 6) and Booster and VS converters (PF2 to 5), which are series connected to Main converters. SN and FDU systems comprise high current DC circuit breakers and resistors for generating high voltage (SN) and to dissipate magnetic energy (FDUs). High transient voltages can arise due to the switching operation of SN and FD and the characteristics of resistors and stray components of DC distribution systems. Also, faults in power supply control such as shorts or grounding faults can produce higher voltages between terminals and between terminal and ground. Therefore, the design of the coil insulation, coil terminal regions, feeders, feed throughs, pipe breaks and instrumentation must take account of these high voltages during normal and abnormal conditions. Voltage insulation level can be defined and it is necessary to test the coils at higher voltages, to be sure of reliable performance during the lifetime of operation. This paper describes the fault analysis of the TF, CS and PF coil power supply systems, taking account of the stray parameter of the power supply and switching systems and inductively coupled superconducting coil models. Resistor grounding systems are included in the simulation model and all fault conditions such as converter hardware and software faults, switching system hardware and software faults, DC short circuits and single grounding faults are simulated. The occurrence of two successive faults

  2. Preliminary results of the US pool-boiling coils from the IFSMTF full-array tests

    International Nuclear Information System (INIS)

    Lue, J.W.; Dresner, L.; Lubell, M.S.; Luton, J.N.; McManamy, T.J.; Shen, S.S.

    1986-01-01

    The Large Coil Task to develop superconducting magnets for fusion reactors, is now in the midst of full-array tests in the International Fusion Superconducting Magnet Test Facility at Oak Ridge National Laboratory. Included in the test array are two pool-boiling coils designed and fabricated by US manufacturers, General Dynamics/Convair Division and General Electric/Union Carbide Corporation. So far, both coils have been energized to full design currents in the single-coil tests, and the General Dynamics coil has reached the design point in the first Standard-I full-array test. Both coils performed well in the charging experiments. Extensive heating tests and the heavy instrumentation of these coils have, however, revealed some generic limitations of large pool-boiling superconducting coils. Details of these results and their analyses are reported

  3. Trim coil power supplies

    International Nuclear Information System (INIS)

    Haisler, R.; Peeler, H.; Zajicek, W.

    1985-01-01

    The 18 trim coil power supplies have been constructed and are now in place in the K500 pit and pit mezzanine. Final wiring of the primary power and control power is proceeding along with installation of cooling water supplies. The supplies are expected to be ready for final testing into resistive loads at the beginning of June, 1985

  4. Cooked meat products made of coarsely ground pork: the main bacterial strains of bacterial flora, their heat resistance and effect on spoilage

    Directory of Open Access Journals (Sweden)

    Esko Petäjä

    1993-09-01

    Full Text Available This study was conducted to investigate the bacterial flora of the surface layer and the core of meat products made of coarsely ground pork at the moment of spoilage when stored at 7°C or 4°C. The dominating strains were isolated, their heat resistance was studied in APT-broth, on APT-agar and in coarsely ground cured pork, and their growth after heating and effect on spoilage were followed in coarsely ground cured pork. The first signs of spoilage appeared in the surface layer of the products. The strains were coccoid lactic acid bacteria with counts ranging from 3,5 to 7.8 log cfu (colony forming units/g. They survived only accidentally after heating for 15 minutes at 72°C in APT-broth. The core of the products contained only coccoid lactic acid bacteria or only pseudomonads or both as the main bacterial strains. The counts ranged from 2.6 to 6.0 log cfu/g. Most of the strains isolated from the core survived after heating for 30 minutes at 72°C in APT-broth in at least three tests out of six. The most noticeable result of the study was the occurence of heat-resistant pseudomonads in the core. It must be pointed out that all pseudomonads found survived after heating for 60 minutes at 72°C in APT-broth, and often after heating for 15 minutes at 72°C in coarsely ground cured pork (core 72°C. The cfu number of the two most heat-resistant streptococcus strains decreased only 1 log unit over 15 minutes at 72°C in coarsely ground cured pork. The numbers of inoculated pseudomonads decreased but those of streptococci rose by a maximum of 1 log unit when the experimental porks were kept at 4°C after heating. This indicates that streptococci and pseudomonads probably do not constitute a serious spoilage factor in cooked meat products, but spoilage is generally effected by bacteria which have contaminated the surface layer of the products after heat treatment.

  5. On the influence of viaduct and ground heating on pollutant dispersion in 2D street canyons and toward single-sided ventilated buildings

    Science.gov (United States)

    This paper employs Computational Fluid Dynamic (CFD) simulations to investigate the influence of ground heating intensities and viaduct configurations on gaseous and particle dispersion within two-dimensional idealized street canyons (typical aspect ratio H/W=1) and their transpo...

  6. Effects of heat stress and probiotic supplementation on protein functionality and oxidative stability of ground chicken leg meat during display storage

    Science.gov (United States)

    The objective of this study was to evaluate effects of heat stress and probiotic supplementation on protein functionality and oxidative stability of ground chicken leg meat during display storage. Two hundred and forty 1-day-old male chicks (5 bird per pen) were randomly subjected to four treatments...

  7. Structural design of the superconducting Poloidal Field coils for the Tokamak Physics Experiment

    International Nuclear Information System (INIS)

    O'Connor, T.G.; Zbasnik, J.P.

    1993-01-01

    The Tokamak Physics Experiment concept design uses superconducting coils made from cable-in-conduit conductor to accomplish both magnetic confinement and plasma initiation. The Poloidal Field (PF) magnet system is divided into two subsystems, the central solenoid and the outer ring coils, the latter is focus of this paper. The eddy current heating from the pulsed operation is excessive for a case type construction; therefore, a ''no case'' design has been chosen. This ''no case'' design uses the conductor conduit as the primary structure and the electrical insulation (fiberglass/epoxy wrap) as a structural adhesive. The model integrates electromagnetic analysis and structural analysis into the finite element code ANSYS to solve the problem. PF coil design is assessed by considering a variety of coil current wave forms, corresponding to various operating modes and conditions. The structural analysis shows that the outer ring coils are within the requirements of the fatigue life and fatigue crack growth requirements. The forces produced by the Toroidal Field coils on the PF coils have little effect on the maximum stresses in the PF coils. In addition in an effort to reduce the cost of the coils new elongated PF coils design was proposed which changes the aspect ratio of the outer ring coils to reduce the number of turns in the coils. The compressive stress in the outer ring coils is increased while the tensile stress is decreased

  8. Eccentric Coil Test Facility (ECTF)

    International Nuclear Information System (INIS)

    Burn, P.B.; Walstrom, P.L.; Anderson, W.C.; Marguerat, E.F.

    1975-01-01

    The conceptual design of a facility for testing superconducting coils under some conditions peculiar to tokamak systems is given. A primary element of the proposed facility is a large 25 MJ background solenoid. Discussions of the mechanical structure, the stress distribution and the thermal stability for this coil are included. The systems for controlling the facility and diagnosing test coil behavior are also described

  9. Modular coils: a promising toroidal-reactor-coil system

    International Nuclear Information System (INIS)

    Chu, T.K.; Furth, H.P.; Johnson, J.L.; Ludescher, C.; Weimer, K.E.

    1981-04-01

    The concept of modular coils originated from a need to find reactor-relevant stellarator windings, but its usefulness can be extended to provide an externally applied, additional rotational transform in tokamaks. Considerations of (1) basic principles of modular coils, (2) types of coils, (3) types of configurations (general, helically symmetric, helically asymmetric, with magnetic well, with magnetic hill), (4) types of rotational transform profile, and (5) structure and origin of ripples are given. These results show that modular coils can offer a wide range of vacuum magnetic field configurations, some of which cannot be obtained with the classical stellarator or torsatron coil configuration

  10. Fabrication of built-up conductors for large pulsed coils

    International Nuclear Information System (INIS)

    Henke, M.D.; Schermer, R.I.

    1979-01-01

    The development work was performed to provide a low-loss, cryostable conductor capable of carrying 5 kA at 3 T for a 30-MJ coil cycled at 0.35 Hz. Much of the work is relevant to conductor development for other pulsed coils, such as a tokamak induction heating coil. As part of the development process, various conductor configurations were subjected to ac loss measurements, stability tests, electrical resistance measurements, and mechanical load-bearing and mechanical fatigue tests. The result is a conductor that appears to satisfy the design criteria with a considerable safety margin

  11. Optimization of Coil Element Configurations for a Matrix Gradient Coil.

    Science.gov (United States)

    Kroboth, Stefan; Layton, Kelvin J; Jia, Feng; Littin, Sebastian; Yu, Huijun; Hennig, Jurgen; Zaitsev, Maxim

    2018-01-01

    Recently, matrix gradient coils (also termed multi-coils or multi-coil arrays) were introduced for imaging and B 0 shimming with 24, 48, and even 84 coil elements. However, in imaging applications, providing one amplifier per coil element is not always feasible due to high cost and technical complexity. In this simulation study, we show that an 84-channel matrix gradient coil (head insert for brain imaging) is able to create a wide variety of field shapes even if the number of amplifiers is reduced. An optimization algorithm was implemented that obtains groups of coil elements, such that a desired target field can be created by driving each group with an amplifier. This limits the number of amplifiers to the number of coil element groups. Simulated annealing is used due to the NP-hard combinatorial nature of the given problem. A spherical harmonic basis set up to the full third order within a sphere of 20-cm diameter in the center of the coil was investigated as target fields. We show that the median normalized least squares error for all target fields is below approximately 5% for 12 or more amplifiers. At the same time, the dissipated power stays within reasonable limits. With a relatively small set of amplifiers, switches can be used to sequentially generate spherical harmonics up to third order. The costs associated with a matrix gradient coil can be lowered, which increases the practical utility of matrix gradient coils.

  12. Ignition experiment in a single-turn-coil tokamak

    International Nuclear Information System (INIS)

    Carrera, R.; Driga, M.; Gully, J.H.

    1989-01-01

    A novel concept for a fusion ignition experiment, IGNITEX proposed along the lines of previous ideas for a compact thermonuclear device is analyzed. A single-turn-coil tokamak is analyzed. A single-turn-coil tokamak supplied by homopolar generators can ohmically heat a DT plasma to ignition conditions and maintain a thermally stable ignited phase for about ten energy confinement times. The IGNITEX experiment can provide a simple and relatively inexpensive way to produce and control ignited plasmas for scientific study

  13. Oval gradient coils for an open magnetic resonance imaging system with a vertical magnetic field.

    Science.gov (United States)

    Matsuzawa, Koki; Abe, Mitsushi; Kose, Katsumi; Terada, Yasuhiko

    2017-05-01

    Existing open magnetic resonance imaging (MRI) systems use biplanar gradient coils for the spatial encoding of signals. We propose using novel oval gradient coils for an open vertical-field MRI. We designed oval gradients for a 0.3T open MRI system and showed that such a system could outperform a traditional biplanar gradient system while maintaining adequate gradient homogeneity and subject accessibility. Such oval gradient coils would exhibit high efficiency, low inductance and resistance, and high switching capability. Although the designed oval Y and Z coils showed more heat dissipation and less cooling capability than biplanar coils with the same gap, they showed an efficient heat-dissipation path to the surrounding air, which would alleviate the heat problem. The performance of the designed oval-coil system was demonstrated experimentally by imaging a human hand. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The Role of Quench-back in the Passive Quench Protection of Long Solenoids with Coil Sub-division

    International Nuclear Information System (INIS)

    Green, Michael A.; Guo, XingLong; Wang, Li; Pan, Heng; Wu, Hong

    2009-01-01

    This paper describes how a passive quench protection system can be applied to long superconducting solenoid magnets. When a solenoid coil is long compared to its thickness, the magnet quench process will be dominated by the time needed for uench propagation along the magnet length. Quench-back will permit a long magnet to quench more rapidly in a passive way. Quenchback from a conductive (low resistivity) mandrel is essential for spreading the quench along the length of a magnet. The andrel must be inductively coupled to the magnet circuit that is being quenched. Current induced in the mandrel by di/dt in the magnet produces heat in the mandrel, which in turn causes the superconducting coil wound on the mandrel to quench. Sub-divisions often employed to reduce the voltages to ground within the coil. This paper explores when it is possible for quench-back to be employed for passive quench protection. The role of sub-division of the coil is discussed for long magnets.

  15. Evaluation of the Internal and Borehole Resistances during Thermal Response Tests and Impact on Ground Heat Exchanger Design

    Directory of Open Access Journals (Sweden)

    Louis Lamarche

    2017-12-01

    Full Text Available The main parameters evaluated with a conventional thermal response test (TRT are the subsurface thermal conductivity surrounding the borehole and the effective borehole thermal resistance, when averaging the inlet and outlet temperature of a ground heat exchanger with the arithmetic mean. This effective resistance depends on two resistances: the 2D borehole resistance (Rb and the 2D internal resistance (Ra which is associated to the short-circuit effect between pipes in the borehole. This paper presents a field method to evaluate these two components separately. Two approaches are proposed. In the first case, the temperature at the bottom of the borehole is measured at the same time as the inlet and outlet temperatures as done in a conventional TRT. In the second case, different flow rates are used during the experiment to infer the internal resistance. Both approaches assumed a predefined temperature profile inside the borehole. The methods were applied to real experimental tests and compared with numerical simulations. Interesting results were found by comparison with theoretical resistances calculated with the multipole method. The motivation for this work is evidenced by analyzing the impact of the internal resistance on a typical geothermal system design. It is shown to be important to know both resistance components to predict the variation of the effective resistance when the flow rate and the height of the boreholes are changed during the design process.

  16. Predicting performance of a ground-source heat pump system using fuzzy weighted pre-processing-based ANFIS

    Energy Technology Data Exchange (ETDEWEB)

    Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, Firat University, 23279 Elazig (Turkey); Sengur, Abdulkadir [Department of Electronic and Computer Science, Faculty of Technical Education, Firat University, 23119 Elazig (Turkey)

    2008-12-15

    The goal of this work is to predict the daily performance (COP) of a ground-source heat pump (GSHP) system with the minimum data set based on an adaptive neuro-fuzzy inference system (ANFIS) with a fuzzy weighted pre-processing (FWP) method. To evaluate the effectiveness of our proposal (FWP-ANFIS), a computer simulation is developed on MATLAB environment. The comparison of the proposed hybridized system's results with the standard ANFIS results is carried out and the results are given in the tables. The efficiency of the proposed method was demonstrated by using the 3-fold cross-validation test. The statistical methods, such as the root-mean squared (RMS), the coefficient of multiple determinations (R{sup 2}) and the coefficient of variation (cov), are given to compare the predicted and actual values for model validation. The average R{sup 2} values is 0.9998, the average RMS value is 0.0272 and the average cov value is 0.7733, which can be considered as very promising. The data set for the COP of GSHP system available included 38 data patterns. The simulation results show that the FWP-based ANFIS can be used in an alternative way in these systems. The prediction results of the proposed structure were much better than the standard ANFIS results. Therefore, instead of limited experimental data found in the literature, faster and simpler solutions are obtained using hybridized structures such as FWP-based ANFIS. (author)

  17. Structural analysis for the joint of the ITER ELM coil

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shanwen, E-mail: zhangshanwen123@163.com [College of Mechanical Engineering Yangzhou University, Yangzhou 225127 (China); Song, Yuntao; Wang, Zhongwei; Ji, Xiang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 200031 (China); Zhang, Jianfeng [College of Mechanical Engineering Yangzhou University, Yangzhou 225127 (China)

    2017-01-15

    Highlights: • The FE sub-model method is feasible and rapid for the joint design. • The components meet the static and fatigue criteria. • Nuclear heat is the key factor for the joint design. - Abstract: The joint is an important component of the Edge Localized Modes (ELM) coils in fusion reactor, which is used to connect the ELM coils. Like the ELM coils, the joints work in an environment with high radiation levels, high temperature and high magnetic field. These joints are mainly subject to nuclear heat from the plasma and cyclic electromagnetic (EM) loads induced by the interaction of ELM coil current with magnetic fields. Take the joint of ITER ELM coil for example. In order to assure the structural integrity of joints under these loads, it is necessary to estimate the strength and fatigue of the joints. As a local model, the joint without ELM coil is investigated by the sub-model method. Results show that the finite element sub-model method is feasible and rapid for the joint design. The maximum magnetic flux intensity occurs in the axial direction for the joint local reference, which parallels with the current and corresponds to the toroidal direction of the ITER. The two areas at the top of the Inconel sleeve appear high temperature. For the joint, the conductor, jacket and sleeve can meet the static and fatigue criteria and the joint design is valid and feasible. The thermal load from the nuclear heat is the key factor for the joint design.

  18. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1986-01-01

    The equilibrium and translational kinematics of Field-Reversed Configurations (FRCs) in a cylindrical coil which does not conserve flux are problems that arise in connection with adiabatic compressional heating. In this paper, they consider several features of the problem of FRC translation into a compression coil. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an abrupt transition model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  19. Soil Thermal Balance Analysis for a Ground Source Heat Pump System in a Hot-Summer and Cold-Winter Region

    Directory of Open Access Journals (Sweden)

    Zhongchao Zhao

    2018-05-01

    Full Text Available As a renewable and high energy efficiency technology providing air conditioning and domestic hot water, the ground source heat pump system (GSHPS has been extensively used worldwide in recent years. Compared with conventional systems, GSHPSs with heat recovery reject less heat into the soil and extract more heat from it, which can help reduce soil thermal imbalance in hot-summer and cold-winter regions. In this paper, conventional GSHPS, and GSHPS with different heat recovery ratios, in a typical city were compared based on thermal imbalance ratios, average soil temperatures and soil temperature increases. The transient system simulation software was used to simulate the operation performance of GSHPS. The thermal imbalance ratio and soil temperature decreased with increasing heat recovery ratio. After 20 years of operation, the soil thermal imbalance ratios of the GSHPS were 29.2%, 21.1%, 16%, and 5.2%, and the soil temperature rises were 8.78 °C, 5.25 °C, 3.44 °C, and 0.34 °C, while the heat recovery ratios were 0, 18%, 30% and 53%, respectively. Consequently, a GSHPS with heat recovery is a potentially efficient and economical approach for buildings in hot-summer and cold-winter regions.

  20. Numerical Study of Heat Transfer during Artificial Ground Freezing Combined with Groundwater Flow based on in-situ Measurement

    Science.gov (United States)

    Hu, R.; Liu, Q.

    2016-12-01

    For civil engineering projects, especially in the subsurface with groundwater, the artificial ground freezing (AGF) method has been widely used. Commonly, a refrigerant is circulated through a pre-buried pipe network to form a freezing wall to support the construction. In many cases, the temperature change is merely considered as a result of simple heat conduction. However, the influence of the water-ice phase change on the flow properties should not be neglected, if large amount of groundwater with high flow velocities is present. In this work, we perform a 2D modelling (software: Comsol Multiphysics) of an AFG project of a metro tunnel in Southern China, taking groundwater flow into account. The model is validated based on in-situ measurement of groundwater flow and temperature. We choose a cross section of this horizontal AGF project and set up a model with horizontal groundwater flow normal to the axial of the tunnel. The Darcy velocity is a coupling variable and related to the temperature field. During the phase change of the pore water and the decrement of permeability in freezing zone, we introduce a variable of effective hydraulic conductivity which is described by a function of temperature change. The energy conservation problem is solved by apparent heat capacity method and the related parameter change is described by a step function (McKenzie, et. al. 2007). The results of temperature contour maps combined with groundwater flow velocity at different times indicate that the freezing wall appears in an asymmetrical shape along the groundwater flow direction. It forms slowly and on the upstream side the thickness of the freezing wall is thinner than that on the downstream side. The closure time of the freezing wall increases at the middle of the both up and downstream sides. The average thickness of the freezing wall on the upstream side is mostly affected by the groundwater flow velocity. With the successful validation of this model, this numerical

  1. Studies of a thermal energy storage unit with ice on coils; Ice on coil gata kori chikunetsuso no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Ito, S; Miura, N [Kanagawa Institute of Technology, Kanagawa (Japan)

    1996-10-27

    Study was made of an ice-on-coil heat storage tank for power load levelling. Prior to the prediction of performance of the system as a whole, the performance of the heat storage tank itself needs to be predicted. A brine (35.9% water solution of ethylene glycol) cooled by a refrigerating machine was poured from the upper end of the piping in the heat storage tank (consisting of 19 spiral pipes or coils arranged in parallel in the vertical direction) for the collection of ice around the coils. Ice grew thicker with the passage of time but there was no remarkable decrease in the transfer of heat because there was an increase in the area of contact between ice and water, and the brine exit temperature remained constant over a prolonged period of time. There was a close agreement between experiment results and theoretical conclusions throughout the heat accumulation process, including changes with time in the thickness of ice on the coils, all pointing to the appropriateness of this analytical effort. To melt the ice, water was poured into the tank top at a predetermined rate. Water chilly at 2-4{degree}C was recovered at the tank bottom, stable in the amount produced. As for the use of spiral pipes for making ice, the laminar heat transfer rate in such pipes are supposed to be more than two times higher than that in straight pipes, and this was quite effective in accelerating heat transfer. 7 refs., 11 figs.

  2. Development work for the Japanese LCT coil and its design and construction

    International Nuclear Information System (INIS)

    Shimamoto, Susumu; Ando, Toshinari; Tsuji, Hiroshi; Yasukochi, Ko

    1984-01-01

    This paper describes design, verification tests, and construction of the Japanese test coil for the Large Coil Task (LCT). Japan Atomic Energy Research Institute (JAERI) signed on the LCT international agreement under the International Energy Agency (IEA) in 1978, and since then JAERI has been working to develop the Japanese LCT coil to explore the problems of design and construction of tokamak toroidal coil. Based on the common requirements of the LCT, the Japanese LCT coil was designed to be a pool-cooled NbTi fully-stabilized coil whose operating current is 10,220 A at 8 T. Through research and development of the Japanese LCT coil, new advances in the super-conducting coil technology were obtained, such as mechanically and chemically treated conductor surface that has high heat transfer about four times as much as usual ones, nitrogen-strengthened stainless steel that has the yield strength twice as much as usual stainless steel, NbTi filaments those have the critical current density twice as much as those before LCT, and so on. These advances have enabled to construct the Japanese LCT coil and it was completed in the spring of 1982. During the construction of the coil, new fabrication techniques were obtained to wind large current conductor into a mechanically rigid coil and thus to construct a totally stable large coil. (author)

  3. Thermal Analysis of Cryocooler-Cooled Bi2223 Pulsed Coil

    International Nuclear Information System (INIS)

    Miyazaki, H; Chigusa, S; Tanaka, I; Iwakuma, M; Funaki, K; Hayashi, H; Tomioka, A

    2006-01-01

    We fabricated a cryocooler-cooled Bi2223 superconducting pulsed coil and experimentally studied thermal runaway in dc or ac operation. We carried out numerical simulation of thermal properties of the coil in order to explain thermal runaway of the coil. Firstly, we analyzed the total heat generation of flux-flow loss and ac loss inside the winding from the experimental results of the external field losses and the E-J characteristics for the Bi2223 strands. Secondly, we numerically simulated the thermal properties by using 2- dimensional heat conduction equation with axial symmetry. The numerical simulation shows the relation between the initiation of thermal runaway and the temperature distribution with highly concentrated heat source in the winding. We have a semi-quantitative agreement between the numerical results and the experimental ones for the condition of the thermal runaway

  4. Surface-near geothermal energy. Ground coupled heat pumps and underground thermal energy storage; Oberflaechennahe Geothermie. Erdgekoppelte Waermepumpen und unterirdische thermische Energiespeicher

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Within the eleventh International User Forum at 27th/28th September, 2011 in Regensburg (Federal Republic of Germany) the following lectures were held: (1) Ecologic evaluation of heat pumps - a question of approach (Roland Koenigsdorff); (2) An actual general comment to WHG, the preparations for the new VAUwS and possible consequences on the surface-near geothermal energy (Walker-Hertkorn); (3) Field-test experiences: Ground source heat pumps in small residential buildings (Jeannette Wapler); (4) GeoT*SOL basic - Program for the evaluation and simulation of heat pump systems (Bernhard Gatzka); (5) Monitoring and modelling of geothermal heat exchanger systems (Fabian Ochs); (6) Thermal response tests for the quality assurance of geothermal heat probes (Markus Proell); (7) Process of determining an untroubled soil temperature in comparison (Andreas Koehler); (8) Borehole resistance - Is the TRT measured value also the planning value? (Roland Koenigsdorff); (9) Consideration of the heat transport in geothermal probes (Martin Konrad); (10) Process of evaluation the sealing of geothermal probes with backfilling materials (Manfred Reuss); (11) Quality assessment of geothermal probes in real standard (Mathieu Riegger); (12) Comparison of flat collectors salt water and direct evaporation, design, impacs, consequences (Bernhard Wenzel); (13) Non-covered photovoltaic thermal collectors in heat pump systems (Erik Bertram); (14) Seasonal geothermal probe-heat storage - Heat supply concepts for objects with overbalancing heating level of more than 100 kW (Volker Liebel); (15) Application of geothermal probe fields as a cold storage (Rolf Wagner); (16) Geothermal energy and waste water warmth: State of the art and new technologies for a combined utilization (Wolfram Stodtmeister); (17) Integration of a heat pump into a solar supported local heat supply in Neckarsulm (Janet Nussbicker-Lux); (18) Regenerative heating with photovoltaics and geothermal energy (Christoph Rosinski

  5. Progress of the ITER Correction Coils in China

    CERN Document Server

    Wei, J; Han, S; Yu, X; Du, S; Li, C; Fang, C; Wang, L; Zheng, W; Liu, L; Wen, J; Li, H; Libeyre, P; Dolgetta, N; Cormany, C; Sgobba, S

    2014-01-01

    The ITER Correction Coils (CC) include three sets of six coils each, distributed symmetrically around the tokamak to correct error fields. Each pair of coils, located on opposite sides of the tokamak, is series connected with polarity to produce asymmetric fields. The manufacturing of these superconducting coils is undergoing qualification of the main fabrication processes: winding into multiple pancakes, welding helium inlet/outlet on the conductor jacket, turn and ground insulation, vacuum pressure impregnation, inserting into an austenitic stainless steel case, enclosure welding, and assembling the terminal service box. It has been proceeding by an intense phase of R\\&D, trials tests, and final adjustment of the tooling. This paper mainly describes the progress in ASIPP for the CC manufacturing process before and on qualification phase and the status of corresponding equipment which are ordered or designed for each process. Some test results for the key component and procedure are also presented.

  6. Nonazeotropic Heat Pump

    Science.gov (United States)

    Ealker, David H.; Deming, Glenn

    1991-01-01

    Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.

  7. Feasibility Study: Ductless Hydronic Distribution Systems with Fan Coil Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Springer, D.; Dakin, B.; Backman, C.

    2012-07-01

    The primary objectives of this study are to estimate potential energy savings relative to conventional ducted air distribution, and to identify equipment requirements, costs, and barriers with a focus on ductless hydronic delivery systems that utilize water-to-air terminal units in each zone. Results indicate that annual heating and cooling energy use can be reduced by up to 27% assuming replacement of the conventional 13 SEER heat pump and coil with a similarly rated air-to-water heat pump.

  8. Fabrication and Analysis of 150 mm Aperture Nb$_{3}$Sn LARP MQXF Coils

    CERN Document Server

    Holik, E F; Anerella, M; Bossert, R; Cavanna, E; Cheng, D; Dietderich, D R; Ferracin, P; Ghosh, A K; Izquierdo Bermudez, S; Krave, S; Nobrega, A; Perez, J C; Pong, I; Rochepault; Sabbi, G L; Schmalzle, J; Yu, M

    2016-01-01

    The US LHC Accelerator Research Program (LARP) and CERN are combining efforts for the HiLumi-LHC upgrade to design and fabricate 150 mm aperture, interaction region quadrupoles with a nominal gradient of 130 T/m using Nb$_{3}$Sn. To successfully produce the necessary long MQXF triplets, the HiLumi-LHC collaboration is systematically reducing risk and design modification by heavily relying upon the experience gained from the successful 120 mm aperture LARP HQ program. First generation MQXF short (MQXFS) coils were predominately a scaling up of the HQ quadrupole design allowing comparable cable expansion during Nb$_{3}$Sn formation heat treatment and increased insulation fraction for electrical robustness. A total of 13 first generation MQXFS coils were fabricated between LARP and CERN. Systematic differences in coil size, coil alignment symmetry, and coil length contraction during heat treatment are observed and likely due to slight variances in tooling and insulation/cable systems. Analysis of coil cross sect...

  9. Extension and application of a scaling technique for duplication of in-flight aerodynamic heat flux in ground test facilities

    NARCIS (Netherlands)

    Veraar, R.G.

    2009-01-01

    To enable direct experimental duplication of the inflight heat flux distribution on supersonic and hypersonic vehicles, an aerodynamic heating scaling technique has been developed. The scaling technique is based on the analytical equations for convective heat transfer for laminar and turbulent

  10. Coil Optimization for HTS Machines

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Abrahamsen, Asger Bech

    An optimization approach of HTS coils in HTS synchronous machines (SM) is presented. The optimization is aimed at high power SM suitable for direct driven wind turbines applications. The optimization process was applied to a general radial flux machine with a peak air gap flux density of ~3T...... is suitable for which coil segment is presented. Thus, the performed study gives valuable input for the coil design of HTS machines ensuring optimal usage of HTS tapes....

  11. Epoxy resin casting of trim coils for superconducting cyclotron

    International Nuclear Information System (INIS)

    Hajra, D.P.; Sarkar, S.C.; Saha, Subimal; Chaudhuri, J.; Bhandari, R.K.

    2006-01-01

    The life of any magnet depends on the soundness of the coil insulation, its aging properties and initial and final endurance limitations. The insulation of water-cooled trim coils for superconducting cyclotron is made of glass fibre tape with heat cured unfilled epoxy resin combination. This type of insulation has been selected to achieve excellent stability against thermal and electromagnetic stresses, tight dimensional control, good dielectric strength, non-hygroscopic and considerably low vapour-pressure as it will be inside rough vacuum. The process development and the difficulties encountered for appropriate selection of epoxy resin combination, potting, vacuum process, curing cycle, control of coil dimension to achieve a sound coil absolutely free from cracks, trapped air and voids has been discussed. (author)

  12. Residual stress measurements in coil, linepipe and girth welded pipe

    International Nuclear Information System (INIS)

    Law, M.; Prask, H.; Luzin, V.; Gnaeupel-Herold, T.

    2006-01-01

    Residual stresses in gas pipelines come from forming operations in producing the coil and pipe, seam welding the pipe, and girth welding pipes together to form a gas pipeline. Welding is used extensively in gas pipelines, the welds are made without post weld heat treatment. The three normal stresses were measured by neutron diffraction for three types of sample: coil, unwelded rings cut from the pipe made from this coil, and girth welded rings cut from linepipe. All three specimens came from three thicknesses of manufacture (5.4, 6.4, and 7.1 mm). The welds are manual metal arc cellulosic electrode welds made in X70 linepipe, these were measured at 5 through-thickness positions at 19 locations (from the center of the weld up to 35 mm away from the weld) with a spatial resolution of 1 mm 3 . The coil and unwelded rings were measured at the same five through-thickness positions

  13. Effects of heat stress and probiotic supplementation on protein functionality and oxidative stability of ground chicken leg meat during display storage.

    Science.gov (United States)

    Kim, Hyun-Wook; Kim, Ji-Han; Yan, Feifei; Cheng, Heng-Wei; Brad Kim, Yuan H

    2017-12-01

    The present study aimed to evaluate the effects of heat stress and probiotic supplementation on protein functionality and oxidative stability of ground chicken leg during display storage. Two hundred and forty, 1-day-old male chicks (5 birds per pen) were subjected to four treatments in a 2 (thermoneutral condition at 21 °C and cyclic heat stress at 32-21-32 °C for 10 h day -1 ) × 2 (regular diet with 0 or 0.25 g kg -1 Bacillus subtilis) factorial design. Chickens were harvested at day 46, and pairs of whole legs were collected at 1 day postmortem. The chicken legs were deboned, ground, tray-packaged with oxygen-permeable film, and displayed for 3 days. Heat stress and probiotic supplementation had no impact on pH, water-holding capacity, color, protein functionality, lipid lipolysis and lipid/protein oxidation stability (P > 0.05). Display storage increased the pH and lipid oxidation of ground chicken legs (P chicken leg meat. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Large superconducting coil fabrication development

    International Nuclear Information System (INIS)

    Brown, R.L.; Allred, E.L.; Anderson, W.C.; Burn, P.B.; Deaderick, R.I.; Henderson, G.M.; Marguerat, E.F.

    1975-01-01

    Toroidal fields for some fusion devices will be produced by an array of large superconducting coils. Their size, space limitation, and field requirements dictate that they be high performance coils. Once installed, accessibility for maintenance and repairs is severely restricted; therefore, good reliability is an obvious necessity. Sufficient coil fabrication will be undertaken to develop and test methods that are reliable, fast, and economical. Industrial participation will be encouraged from the outset to insure smooth transition from development phases to production phases. Initially, practice equipment for three meter bore circular coils will be developed. Oval shape coil forms will be included in the practice facility later. Equipment that is more automated will be developed with the expectation of winding faster and obtaining good coil quality. Alternate types of coil construction, methods of winding and insulating, will be investigated. Handling and assembly problems will be studied. All technology developed must be feasible for scaling up when much larger coils are needed. Experimental power reactors may need coils having six meter or larger bores

  15. Solar assisted heat pump on air collectors: A simulation tool

    Energy Technology Data Exchange (ETDEWEB)

    Karagiorgas, Michalis; Galatis, Kostas; Tsagouri, Manolis [Department of Mechanical Engineering Educators, ASPETE, N. Iraklio, GR 14121 (Greece); Tsoutsos, Theocharis [Environmental Engineering Dept., Technical University of Crete, Technical University Campus, GR 73100, Chania (Greece); Botzios-Valaskakis, Aristotelis [Centre for Renewable Energy Sources (CRES), 19th km Marathon Ave., GR 19001, Pikermi (Greece)

    2010-01-15

    The heating system of the bioclimatic building of the Greek National Centre for Renewable Energy Sources (CRES) comprises two heating plants: the first one includes an air source heat pump, Solar Air Collectors (SACs) and a heat distribution system (comprising a fan coil unit network); the second one is, mainly, a geothermal heat pump unit to cover the ground floor thermal needs. The SAC configuration as well as the fraction of the building heating load covered by the heating plant are assessed in two operation modes; the direct (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but indirectly into the evaporator of the air source heat pump). The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, saving electrical power consumed by the compressor of the heat pump, and therefore, at optimizing the coefficient of performance (COP) of the heat pump due to the increased intake of ambient thermal energy by means of the SAC. Results are given for three research objectives: assessment of the heat pump efficiency whether in direct or indirect heating mode; Assessment of the overall heating plant efficiency on a daily or hourly basis; Assessment of the credibility of the suggested simulation model TSAGAIR by comparing its results with the TRNSYS ones. (author)

  16. Triple Halo Coil: Development and Comparison with Other TMS Coils

    Science.gov (United States)

    Rastogi, Priyam; Hadimani, Ravi; Jiles, David

    Transcranial Magnetic Stimulation (TMS) is a non-invasive stimulation technique that can be used for the treatment of various neurological disorders such as Parkinson's Disease, PTSD, TBI and anxiety by regulating synaptic activity. TMS is FDA approved for the treatment of major depressive disorder. There is a critical need to develop deep TMS coils that can stimulate deeper regions of the brain without excessively stimulating the cortex in order to provide an alternative to surgical methods. We have developed a novel multi-coil configuration called ``Triple Halo Coil'' (THC) that can stimulate deep brain regions. Investigation of induced electric and magnetic field in these regions have been achieved by computer modelling. Comparison of the results due to THC configuration have been conducted with other TMS coils such as ``Halo Coil'', circular coil and ``Figure of Eight'' coil. There was an improvement of more than 15 times in the strength of magnetic field, induced by THC configuration at 10 cm below the vertex of the head when compared with the ``Figure of Eight'' coil alone. Carver Charitable Trust.

  17. The coiled coil motif in polymer drug delivery systems

    Czech Academy of Sciences Publication Activity Database

    Pechar, Michal; Pola, Robert

    2013-01-01

    Roč. 31, č. 1 (2013), s. 90-96 ISSN 0734-9750 R&D Projects: GA ČR GA203/08/0543; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505 Keywords : coiled coil * hydrophilic polymer * recombinant protein Subject RIV: CD - Macromolecular Chemistry Impact factor: 8.905, year: 2013

  18. Nuclear magnetic resonance apparatus having semitoroidal RF coil for use in topical NMR and NMR imaging

    International Nuclear Information System (INIS)

    Fukushima, E.; Assink, R.A.; Roeder, S.B.W.; Gibson, A.A.V.

    1984-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, to enable NMR measurements to be taken from selected regions inside an object, particularly human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other electric field interactions. The coil may be combined with a like orthogonal coil and suitably driven to provide a circularly polarised field; or it may be used in conjunction with a concentrically nested smaller semitoroidal coil to move the maximum field further from the coil assembly. (author)

  19. Thermal and hydraulic analyses of TFTR cooling water system and magnetic field coils

    International Nuclear Information System (INIS)

    Lee, A.Y.

    1975-10-01

    The TFTR toroidal field coils, ohmic heating, hybrid and equilibrium field coils are cooled by water from the machine area cooling water system. The system has the following major equipment and capacities: flow rate of 3600 gpm; ballast tank volume of 5500 gal; pumps of 70.4 m head; chiller refrigeration rating of 3300 tons and connecting pipe of 45.7 cm I.D. The performance of the closed loop system was analyzed and found to be adequate for the thermal loads. The field coils were analyzed with detailed thermal and hydraulic models, including a simulation of the complete water cooling loop. Under the nominal operating mode of one second of toroidal field flat top time and 300 seconds of pulse cycle time, the maximum temperature for the TF coils is 53 0 C; for the OH coils 46 0 C and for the EF coils 39 0 C, which are well below the coil design limit of 120 0 C. The maximum TF coil coolant temperature is 33 0 C which is below the coolant design limit of 100 0 C. The overall pressure loss of the system is below 6.89 x 10 5 Pa (100 psi). With the given chiller refrigeration capacity, the TF coils can be operated to yield up to 4 seconds of flat top time. The TF coils can be operated on a steady state basis at up to 20% of the pulsed duty design current rating of 7.32 kA/coil

  20. Design and fabrication of the active feedback control coils for EAST

    Energy Technology Data Exchange (ETDEWEB)

    Du Shijun [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)], E-mail: dsj@ipp.ac.cn; Liu Xufeng [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)

    2008-10-15

    As the active feedback control coils are located inside vacuum vessel, a reasonable design is important not only for safe operation of the coils but also for reliable operation of EAST (Experimental Advanced Superconducting Tokamak). There are some different characteristics from other coils in the design and fabrication of the coils, such as the insulation structure bearing the high baking temperature, the insulation joint with special flexible structure and the brazing method of the large size conductor inside vacuum vessel. All joints of coils are located outside the vacuum vessel for providing more connection. The conductors of the coils are designed inside the stainless steel tube and actively water cooled to prevent overheating. The ceramic rings with fiberglass tapes are used to separate the conductors and the steel tube. This insulation structure adopted in the coils can bear the high baking temperature of the vacuum vessel and its details are given in the paper. For protecting the hermetic and insulating property of the insulation joint, the small bellows is located on insulation joints to eliminate the forces on the insulator. In the fabrication, the coils are built in sections and then assembled together to form whole coils inside the vacuum vessel. The 8 kHz frequency induction heater is used to braze the conductors for cutting short brazing time and reducing heating area. The electromagnetic loads acting on the current leaders, the electrical parameters of the coil and the coil temperature are also analyzed in this paper.

  1. Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application

    Science.gov (United States)

    Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi

    2015-11-01

    The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40-50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

  2. Parallel connecting poloidal coil system for a doublet tokamak fusion reactor

    International Nuclear Information System (INIS)

    Toffolo, W.E.; Chen, W.Y.; Purcell, J.R.; Wesley, J.C.

    1977-09-01

    A method has been developed for parallel connection of the ohmic heating (OH) coil. The method involves subdividing the OH-coil into a number of parallel connected subcoils, with each subcoil having about 20 turns. Each of the field shaping coils (F-coils) also contains 20 turns, so that when connected to a common power supply, the OH and F-coils are decoupled. The advantages resulting from the scheme are numerous: (1) each F-coil contains a much smaller number of turns compared with the previous design concept, thus the construction and maintenance will be easier; (2) the parallel connected OH-coils form a constant flux envelope, resulting in an inherently lower error field at the plasma and the TF coil region, and this low error field is not sensitive to the variation in location of the OH-coils; (3) the voltage and current ratings of the individual OH coil conductors are reduced; and (4) the low impedance of the OH-coil system greatly improves the possibility of using a homopolar motor generator as a means of achieving flux reversal during startup and plasma current control during the burn cycle

  3. Superconducting coil manufacturing method for low current dc beam line magnets

    International Nuclear Information System (INIS)

    Satti, J.A.

    1977-01-01

    A method of manufacturing superconducting multipole coils for 40 to 50 kG dc beam line magnets with low current is described. Small coils were built and tested successfully to short sample characteristics. The coils did not train after the first cooldown. The coils are porous and well cooled to cope with mechanical instability and energy deposited in the coil from the beam particles. The coils are wound with insulated strand cable. The cable is shaped rectangularly for winding simplicity and good tolerances. After the coil is wound, the insulated strands are electrically connected in series. This reduces the operating current and, most important, improves the coil quench propagation due to heat conduction of one strand adjacent to the other. A well distributed quench allows the magnet energy to distribute more uniformly to the copper in the superconductor wire, giving self-protected coils. A one-meter long, 43 kG, 6-inch bore tube superconducting dipole is now being fabricated. The porous coil design and coil winding methods are discussed

  4. Design and fabrication of the active feedback control coils for EAST

    International Nuclear Information System (INIS)

    Du Shijun; Liu Xufeng

    2008-01-01

    As the active feedback control coils are located inside vacuum vessel, a reasonable design is important not only for safe operation of the coils but also for reliable operation of EAST (Experimental Advanced Superconducting Tokamak). There are some different characteristics from other coils in the design and fabrication of the coils, such as the insulation structure bearing the high baking temperature, the insulation joint with special flexible structure and the brazing method of the large size conductor inside vacuum vessel. All joints of coils are located outside the vacuum vessel for providing more connection. The conductors of the coils are designed inside the stainless steel tube and actively water cooled to prevent overheating. The ceramic rings with fiberglass tapes are used to separate the conductors and the steel tube. This insulation structure adopted in the coils can bear the high baking temperature of the vacuum vessel and its details are given in the paper. For protecting the hermetic and insulating property of the insulation joint, the small bellows is located on insulation joints to eliminate the forces on the insulator. In the fabrication, the coils are built in sections and then assembled together to form whole coils inside the vacuum vessel. The 8 kHz frequency induction heater is used to braze the conductors for cutting short brazing time and reducing heating area. The electromagnetic loads acting on the current leaders, the electrical parameters of the coil and the coil temperature are also analyzed in this paper.

  5. Experiences with field tests: Ground coupled heat pumps in small residential buildings; Feldtesterfahrungen. Erdgekoppelte Waermepumpen in kleineren Wohngebaeuden

    Energy Technology Data Exchange (ETDEWEB)

    Wapler, Jeannette; Guenther, Danny; Miara, Marek [Fraunhofer-Institut fuer Solare Energiesysteme ISE/Thermal Systems and Buildings, Freiburg (Germany)

    2012-07-01

    In the context of two research projects, the Fraunhofer Institute for Solar Energy Systems (Freiburg, Federal Republic of Germany) has surveyed a large number of heat pumps in actual application. In particular, heat pumps in small residential buildings (single-family houses) were examined for new and existing buildings. In addition to the achieved performance factors the temperature profile of the heat sink and heat source was recorded. This temperature profile was evaluated separately for systems with geothermal collectors and systems with geothermal probes. The theoretical assumptions could be confirmed. Influences during the installation, commissioning and operation are identified.

  6. Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

    Science.gov (United States)

    2016-11-21

    through water evaporation , although some cooling also occurs due to sensible heat transfer . Cooling towers are very effective heat transfer devices... evaporator coil connected to the building heating , ventilation, and air conditioning (HVAC) system. The refrigerant evaporates in the coil, removing...vapor is directed to a condensing coil, where the refrigerant vapor condenses back into a liquid, releasing its heat of vaporization. During

  7. Thermal results of the Japanese LCT coil's domestic test

    International Nuclear Information System (INIS)

    Tada, Eisuke; Hiyama, Tadao; Kato, Takashi; Takahashi, Osamu; Shimamoto, Susumu

    1984-01-01

    This paper describes thermal results obtained in the domestic test of the Japanese LCT coil which was constructed at the Japan Atomic Energy Research Institute (JAERI) in order to develop large superconducting coils for fusion in international collaboration proposed by the IEA. The domestic test was carried out from May 13 to June 17 in 1982 by using the test facility named as SETF (Superconducting Engineering Test Facility) which was composed of a 350-l/h helium cryogenic system, a vacuum system, a 30 KA-DC power supply and protection system, and a PDP-11/70 computer system. The cool-down characteristics, heat load, fast discharge characteristics, stability, and warm-up characteristics of the LCT coil were successfully measured in the test. The details of thermal test results acquired in the cool-down, heat load measurement, fast discharge, and warm-up, and the comparison between measurements and calculations are described in this paper. (author)

  8. Tore-Supra: a Tokamak with superconducting toroidal field coils

    International Nuclear Information System (INIS)

    Turck, B.

    1987-07-01

    Tore Supra is a tokamak under construction on the site of Cen Cadarache by the Euratom-CEA Association. The machine technology integrates all problems related to the fabrication and the operation of large superconducting coils and of the associated cryogenic system. Tore Supra will provide a significant experience to prepare the next generation of machines for plasma physics and controlled fusion. Tore Supra is specially designed to implement a large physics program. The superconducting coils make possible the study of plasma confinement in long pulses (more than 60s), the impurities and the stability, and the efficiency of additional heating sources (neutral particle beams and radio frequency heating). The opportunity is taken to recall the particular features and requirements of the superconducting coils of the large future tokamaks in order to point out the problems that have to be faced by any new material (superconducting or not)

  9. Electron Beam Curing of Coil Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Morganstern, K. H. [Radiation Dynamics, Inc., Westbury, NY (United States)

    1969-12-15

    The application of electron accelerators for the rapid curing of coatings on coil processing of steel and aluminium appears to have many practical and economic advantages. This paper discusses this particular application, but in the general framework of electron beam application by industry. Although industry has investigated radiation application for two decades, there have been few applications to date. The reasons for this are discussed as well as the shift in attitude now taking place, indicating a more ready acceptance of radiation processing by industry. This shift is apparent particularly in the coatings field, where the benefits of radiation processing are quite evident. In order to pinpoint these benefits a specific coatings application - coil coating - has been chosen. A typical conventional coil coating line is discussed and compared to a line employing a radiation source. Specific engineering information on the types of electron accelerators suitable for this application; the relative economics of radiation vs. heat curing; and a number of other peripheral advantages of radiation are discussed. (author)

  10. Thermal analysis of track based coils

    Energy Technology Data Exchange (ETDEWEB)

    Davey, K [American MAGLEV, Inc., Edgewater, FL (United States); Zowarka, R [CEM, Austin, TX (United States)

    1996-12-31

    This document examines the temperature rise of coils embedded in a concrete matrix. The ultimate goal is to predict the steady state temperature of the coils subject to a repeated passage of vehicles at a regular interval. The primary concern is in maintaining a maximum temperature which is less than that which would compromise the integrity of the insulation used on the wires. Three techniques are used to examine the problem. First, an analytical approach is used to determine not only the immediate temperature rise of the wire material itself, but also a consevative estimate of the steady state temperature expected. Second, the equations are examined for a one dimensional transient profile of the temperature with time. Finally, a two dimensional steady state boundary element solution is employed to estimate the steady state temperature profile both within the coils and within the rail. In this two dimensional boundary element assessment, an iterative approach is employed to accurately model the heat transfer coefficient h which ultimately defines the steady state temperature. (orig.)

  11. The IEA Large Coil Task

    International Nuclear Information System (INIS)

    Beard, D.S.; Klose, W.; Shimamoto, S.; Vecsey, G.

    1988-01-01

    A multinational program of cooperative research, development, demonstrations, and exchanges of information on superconducting magnets for fusion was initiated in 1977 under an IEA agreement. The first major step in the development of TF magnets was called the Large Coil Task. Participants in LCT were the U.S. DOE, EURATOM, JAERI, and the Departement Federal de l'Interieur of Switzerland. The goals of LCT were to obtain experimental data, to demonstrate reliable operation of large superconducting coils, and to prove design principles and fabrication techniques being considered for the toroidal magnets of thermonuclear reactors. These goals were to be accomplished through coordinated but largely independent design, development, and construction of six test coils, followed by collaborative testing in a compact toroidal test array at fields of 8 T and higher. Under the terms of the IEA Agreement, the United States built and operated the test facility at Oak Ridge and provided three test coils. The other participants provided one coil each. Information on design and manufacturing and all test data were shared by all. The LCT team of each participant included a government laboratory and industrial partners or contractors. The last coil was completed in 1985, and the test assembly was completed in October of that year. Over the next 23 months, the six-coil array was cooled down and extensive testing was performed. Results were gratifying, as tests achieved design-point performance and well beyond. (Each coil reached a peak field of 9 T.) Experiments elucidated coil behavior, delineated limits of operability, and demonstrated coil safety. (orig./KP)

  12. Theory and design of heat exchanger : Double pipe and heat exchanger in abnormal condition

    International Nuclear Information System (INIS)

    Min, Ui Dong

    1996-02-01

    This book introduces theory and design of heat exchanger, which includes HTRI program, multiple tube heat exchanger external heating, theory of heat transfer, basis of design of heat exchanger, two-phase flow, condensation, boiling, material of heat exchanger, double pipe heat exchanger like hand calculation, heat exchanger in abnormal condition such as Jackets Vessel, and Coiled Vessel, design and summary of steam tracing.

  13. Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application

    International Nuclear Information System (INIS)

    Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi

    2015-01-01

    Highlights: • We propose a novel REBCO coil structure which applies thermoplastic resin. • The thermoplastic resin bonds the coil winding and cooling plates. • The adhesiveness of the resin is strong enough to withstand the thermal stress. • The thermoplastic resin does not cause the degradation because of its high viscosity. • We successfully made a full-scale racetrack REBCO coil with the thermoplastic resin. - Abstract: The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40–50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

  14. Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, Katsutoshi, E-mail: mizuno.katsutoshi.14@rtri.or.jp; Ogata, Masafumi; Hasegawa, Hitoshi

    2015-11-15

    Highlights: • We propose a novel REBCO coil structure which applies thermoplastic resin. • The thermoplastic resin bonds the coil winding and cooling plates. • The adhesiveness of the resin is strong enough to withstand the thermal stress. • The thermoplastic resin does not cause the degradation because of its high viscosity. • We successfully made a full-scale racetrack REBCO coil with the thermoplastic resin. - Abstract: The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40–50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

  15. Superconducting toroidal field coil power supply and protection system for NET

    International Nuclear Information System (INIS)

    Hicks, J.B.

    1986-01-01

    A power supply and quench protection system is proposed in which alternate coils are connected in series to produce two separate circuits, each with 8 coils. Both circuits are provided with power supplies comprising rectifier transformers and thyristor equipped Graetz bridges, which are operated at maximum forward voltage (125 V) to charge the coils to 24 kA, 17.75 GJ in ≅ 2 hours and are fully inverted for scheduled discharges. Pulsed firing of the thyristors allows the same power supplies to be used to maintain the currents against resistive losses, without increasing the reactive power consumption or harmonic current generation. Rapid discharges are initiated by opening d.c. circuit breakers to introduce discharge resistors between the coils of each circuit. The maximum possible value of peak voltage-to-ground is then limited to 2.25 times the discharge voltage applied to each coil. A 5 kV discharge voltage allows the coils to be discharged with a time constant of 18.5 s, which is sufficiently rapid to limit the quench ''hot spot'' temperature to 68 K. The coil connections impose sufficient symmetry on the coil current distribution to ensure that no out-of-plane forces are produced on the coils. Even if one circuit breaker fails to interrupt, the variation of coil currents is sufficiently small that the resulting symmetric variation of radial centring forces is acceptable

  16. Experimental and modelling analysis of an office building HVAC system based in a ground-coupled heat pump and radiant floor

    International Nuclear Information System (INIS)

    Villarino, José Ignacio; Villarino, Alberto; Fernández, Francisco Ángel

    2017-01-01

    Highlights: • A case study of a geothermal heat pump in an office building. • A numerical model in EnergyPlus is validated by experimental results. • An energy, economic and environmental analysis is presented. • A comparison with other technologies demonstrates the potential of the system. - Abstract: This paper shows the evaluation of the performance of a ground-coupled heat pump system monitored building providing heating, ventilating and air conditioning to an office building located in Madrid, in Spain. The system consists of one borehole exchanger, heat pump unit, radiant floor system, mechanical ventilation and data control system. A simulation model was performed with EnergyPlus software and validated. The analyzed period corresponds to the most unfavorable weather conditions in heating and cooling mode. The coefficient of performance obtained in heating and cooling mode was 3.86/5.29, considering all the energy consumption elements of the building and the thermal demand corresponding to an office operation. The CO_2 emissions obtained with a value of 34.68 kg corresponding to the period analyzed represents a low CO_2 emission system. The monitored temperatures reached set point values of 22 °C/25 °C, considered as acceptable comfort temperatures. The values obtained in the validated simulation model presented a deviation of 2% respected experimental results in heating and cooling mode. A comparative of COP_s_y_s and CO_2 emissions with other technologies is performed in order to analyze GCHP compared to other available technologies. The GCHP system is presented as a technology that can fully supply the HVAC conditions for a building and environmentally friendly.

  17. Coil protection calculator for TFTR

    International Nuclear Information System (INIS)

    Marsala, R.J.; Lawson, J.E.; Persing, R.G.; Senko, T.R.; Woolley, R.D.

    1989-01-01

    A new coil protection system (CPS) is being developed to replace the existing TFTR magnetic coil fault detector. The existing fault detector sacrifices TFTR operating capability for simplicity. The new CPS, when installed in October of 1988, will permit operation up to the actual coil stress limits parameters in real-time. The computation will be done in a microprocessor based Coil Protection Calculator (CPC) currently under construction at PPL. THe new CPC will allow TFTR to operate with higher plasma currents and will permit the optimization of pulse repetition rates. The CPC will provide real-time estimates of critical coil and bus temperatures and stresses based on real-time redundant measurements of coil currents, coil cooling water inlet temperature, and plasma current. The critical parameter calculations are compared to prespecified limits. If these limits are reached or exceeded, protection action will be initiated to a hard wired control system (HCS), which will shut down the power supplies. The CPC consists of a redundant VME based microprocessor system which will sample all input data and compute all stress quantities every ten milliseconds. Thermal calculations will be approximated every 10ms with an exact solution occurring every second. The CPC features continuous cross-checking of redundant input signal, automatic detection of internal failure modes, monitoring and recording of calculated results, and a quick, functional verification of performance via an internal test system. (author)

  18. Current contact device for a superconducting magnet coil

    International Nuclear Information System (INIS)

    Hieronymus, H.

    1987-01-01

    The invention concerns a current supply device for a superconducting magnet coil to be shortcircuited, with a separating device per coil end, which contains a fixed cooled contact and a moving contact connected to a power supply device and a mechanical actuating device for closing and opening the contacts. When closing the heated contact on to the cooled contact, relatively large quantities of heat can be transferred to the cooled contact and therefore to the connected superconducting coil end and can cause normal conduction there. The invention therefore provides that the mass ratio of the cooled contact to the moving contact is at least 5:1, preferably at least 10:1, and that the cooled contact part is provided, at the end away from the contact area, with means for increasing the area, for example cooling fins and is connected to the coil end has a thermal resistance between the contact area and the coil end of at least 0.2 k/W, preferably at least 0.5 k/W per 1000 A of current to be transmitted. (orig.) [de

  19. Analyses and Comparison of Bulk and Coil Surface Samples from the DWPF Slurry Mix Evaporator

    International Nuclear Information System (INIS)

    Hay, M.; Nash, C.; Stone, M.

    2012-01-01

    Sludge samples from the DWPF Slurry Mix Evaporator (SME) heating coil frame and coil surface were characterized to identify differences that might help identify heat transfer fouling materials. The SME steam coils have seen increased fouling leading to lower boil-up rates. Samples of the sludge were taken from the coil frame somewhat distant from the coil (bulk tank material) and from the coil surface (coil surface sample). The results of the analysis indicate the composition of the two SME samples are very similar with the exception that the coil surface sample shows ∼5-10X higher mercury concentration than the bulk tank sample. Elemental analyses and x-ray diffraction results did not indicate notable differences between the two samples. The ICP-MS and Cs-137 data indicate no significant differences in the radionuclide composition of the two SME samples. Semi-volatile organic analysis revealed numerous organic molecules, these likely result from antifoaming additives. The compositions of the two SME samples also match well with the analyzed composition of the SME batch with the exception of significantly higher silicon, lithium, and boron content in the batch sample indicating the coil samples are deficient in frit relative to the SME batch composition.

  20. Steady-state resistive toroidal-field coils for tokamak reactors

    International Nuclear Information System (INIS)

    Kalnavarns, J.; Jassby, D.L.

    1979-12-01

    If spatially-averaged values of the beta ratio can reach 5 to 10% in tokamaks, as now seems likely, resistive toroidal-field coils may be advantageous for use in reactors intended for fusion-neutron applications. The present investigation has parameterized the design of steady-state water-cooled copper coils of rectangular cross section in order to maximize figures of merit such as the ratio of fusion neutron wall loading to coil power dissipation. Four design variations distinguished by different ohmic-heating coil configurations have been examined. For a wall loading of 0.5 MW/m 2 , minimum TF-coil lifetime costs (including capital and electricity costs) are found to occur with coil masses in the range 2400 to 4400 tons, giving 200 to 250 MW of resistive dissipation, which is comparable with the total power drain of the other reactor subsystems

  1. Remote replacement of TF [toroidal field] and PF [poloidal field] coils for the compact ignition tokamak

    International Nuclear Information System (INIS)

    Macdonald, D.; Watkin, D.C.; Hollis, M.J.; DePew, R.E.; Kuban, D.P.

    1990-01-01

    The use of deuterium-tritium fuel in the Compact Ignition Tokamak will require applying remote handling technology for ex-vessel maintenance and replacement of machine components. Highly activated and contaminated components of the fusion devices auxiliary systems, such as diagnostics and RF heating, must be replaced using remotely operated maintenance equipment in the test cell. In-vessel remote maintenance included replacement of divertor and first wall hardware, faraday shields, and for an in-vessel inspection system. Provision for remote replacement of a vacuum vessel sector, toroidal field coil or poloidal field ring coil was not included in the project baseline. As a result of recent coil failures experienced at a number of facilities, the CIT project decided to reconsider the question of remote recovery from a coil failure and, in January of 1990, initiated a coil replacement study. This study focused on the technical requirements and impact on fusion machine design associated with remote recovery from any coil failure

  2. The transfer function model for dynamic response of wet cooling coils

    International Nuclear Information System (INIS)

    Yao Ye; Liu Shiqing

    2008-01-01

    This paper mainly concerned about the dynamic response model of wet cooling coils that is developed by the Laplace transform method. The theoretic equations are firstly established based on the theory of energy conservation. Then, the transfer functions on the transient responses of wet cooling coils have been deduced using the method of Laplace transform. The transfer functions reveal the dynamic relationships between the inlet variables and the outlet ones of the cooling coils. Partial-fraction method and Newton-Raphson method are both used in the inversion of the transfer functions from the s-domain to τ-domain. To make the dynamic model of wet cooling coils more adaptive, RBFNN method is employed to determine the coefficients of heat and mass transfer. Experiments have been done and manifested that the coefficients of heat and mass transfer by RBFNN will be of great value to the validity of the transient response model of wet cooling coils in this study

  3. Coil for LEAR extraction septum

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    Which way does the current flow ? This intriguing object is the coil for the LEAR extraction septum. There were two septa, first a thin one, then this one, not so thin, somewhat on the borderline between septum and bending magnet.

  4. First coil for the SC

    CERN Multimedia

    CERN PhotoLab

    1955-01-01

    The coils for the SC magnet were stored in the large hangar of the Cointrin Airport (to make sure that they would be available before snow and ice would block the roads and canals from Belgium, where they were built).

  5. Radiation resistant ducted superconductive coil

    International Nuclear Information System (INIS)

    Schleich, A.

    1976-01-01

    The radiation-resistant ducted superconductive coil consists of a helically wound electrical conductor constituted by an electrically conductive core of superconductive material provided with a longitudinally extending cooling duct. The core is covered with a layer of inorganic insulating material and the duct is covered by an electrically conductive metallic gas-tight sheath. The metallic sheaths on adjacent turns of the coil are secured together. 2 Claims, 4 Drawing Figures

  6. The Swiss LCT-coil

    International Nuclear Information System (INIS)

    Vecsey, G.; Benz, H.; Horvath, I.

    1985-01-01

    With delivery of the coil to ORNL on February 4, 1984, the second phase of the Swiss Large Coil Program - design and construction - was terminated. Mainlines of the Swiss design concept are summarized and related to theoretical calculations, experimental results of the supporting program, fabricational experience and first successful test results. An attempt is made to draw preliminary conclusions with regard to the design of future toroidal systems such as NET

  7. The SMES model coil. Fabrication

    International Nuclear Information System (INIS)

    Hanai, Satoshi; Nakamoto, Kazunari; Takahashi, Nobuji

    1998-01-01

    A SMES model coil was fabricated as R and D item in the development of component technologies for a 480 MJ/20 MW SMES pilot plant. The coil consists of four double-pancake windings. The coil is the same diameter but half the number of pancakes that will be needed for a SMES pilot plant. The NbTi cable-in-conduit conductor and superconducting joints between the double pancakes are cooled by a forced flow of supercritical helium. Prior to fabrication, various characteristics of the cable-in-conduit were measured by full-sized short samples from actual conductors and by scaled short samples from scaled conductors. The critical current of the scaled short samples was in agreement with that calculated from one strand of the conductor. The impedance between arbitrary dual-oxide coated strands in the full-size conductor was measured to be smaller than that obtained from two Cr-plated strands, which showed a good degree of stability in another coil. It was estimated that oxide-coated conductors would have high stability. Through fabrication of a model coil, it was demonstrated that a large forced-flow coil for a small-scale 100 kWh SMES device could be manufactured. (author)

  8. The SMES model coil. Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Hanai, Satoshi; Nakamoto, Kazunari; Takahashi, Nobuji [Toshiba Corp., Yokohama, Kanagawa (Japan)] [and others

    1998-07-01

    A SMES model coil was fabricated as R and D item in the development of component technologies for a 480 MJ/20 MW SMES pilot plant. The coil consists of four double-pancake windings. The coil is the same diameter but half the number of pancakes that will be needed for a SMES pilot plant. The NbTi cable-in-conduit conductor and superconducting joints between the double pancakes are cooled by a forced flow of supercritical helium. Prior to fabrication, various characteristics of the cable-in-conduit were measured by full-sized short samples from actual conductors and by scaled short samples from scaled conductors. The critical current of the scaled short samples was in agreement with that calculated from one strand of the conductor. The impedance between arbitrary dual-oxide coated strands in the full-size conductor was measured to be smaller than that obtained from two Cr-plated strands, which showed a good degree of stability in another coil. It was estimated that oxide-coated conductors would have high stability. Through fabrication of a model coil, it was demonstrated that a large forced-flow coil for a small-scale 100 kWh SMES device could be manufactured. (author)

  9. Absence of a long-range ordered magnetic ground state in Pr3Rh4Sn13 studied through specific heat and inelastic neutron scattering

    Science.gov (United States)

    Nair, Harikrishnan S.; Ogunbunmi, Michael O.; Ghosh, S. K.; Adroja, D. T.; Koza, M. M.; Guidi, T.; Strydom, A. M.

    2018-04-01

    Signatures of absence of a long-range ordered magnetic ground state down to 0.36 K are observed in magnetic susceptibility, specific heat, thermal/electrical transport and inelastic neutron scattering data of the quasi-skutterudite compound Pr3Rh4Sn13 which crystallizes in the Yb3Rh4Sn13-type structure with a cage-like network of Sn atoms. In this structure, Pr3+ occupies a lattice site with D 2d point symmetry having a ninefold degeneracy corresponding to J  =  4. The magnetic susceptibility of Pr3Rh4Sn13 shows only a weak temperature dependence below 10 K otherwise remaining paramagnetic-like in the range, 10 K-300 K. From the inelastic neutron scattering intensity of Pr3Rh4Sn13 recorded at different temperatures, we identify excitations at 4.5(7) K, 5.42(6) K, 10.77(5) K, 27.27(5) K, 192.28(4) K and 308.33(3) K through a careful peak analysis. However, no signatures of long-range magnetic order are observed in the neutron data down to 1.5 K, which is also confirmed by the specific heat data down to 0.36 K. A broad Schottky-like peak is recovered for the magnetic part of the specific heat, C 4f, which suggests the role of crystal electric fields of Pr3+ . A crystalline electric field model consisting of 7 levels was applied to C 4f which leads to the estimation of energy levels at 4.48(2) K, 6.94(4) K, 11.23(8) K, 27.01(5) K, 193.12(6) K and 367.30(2) K. The CEF energy levels estimated from the heat capacity analysis are in close agreement with the excitation energies seen in the neutron data. The Sommerfeld coefficient estimated from the analysis of magnetic specific heat is γ = 761(6) mJ K-2 mol-Pr which suggests the formation of heavy itinerant quasi-particles in Pr3Rh4Sn13. Combining inelastic neutron scattering results, analysis of the specific heat data down to 0.36 K, magnetic susceptibility and, electrical and thermal transport, we establish the absence of long-range ordered magnetic ground state in Pr3Rh4Sn13.

  10. Equilibrium field coil concepts for INTOR

    International Nuclear Information System (INIS)

    Strickler, D.J.; Peng, Y.K.M.; Brown, T.G.

    1981-08-01

    Methods are presented for reducing ampere-turn requirements in the EF coil system. It is shown that coil currents in an EF coil system external to the toroidal field coils can be substantially reduced by relaxing the triangularity of a D-shaped plasma. Further reductions are realized through a hybrid EF coil system using both internal and external coils. Equilibrium field coils for a poloidally asymmetric, single-null INTOR configuration are presented. It is shown that the shape of field lines in the plasma scrapeoff region and divertor channel improves as triangularity is reduced, but it does so at the possible expense of achievable stable beta values

  11. Endovascular rescue method for undesirably stretched coil.

    Science.gov (United States)

    Cho, Jae Hoon

    2014-10-01

    Undesirable detachment or stretching of coils within the parent artery during aneurysm embolization can be related with thrombus formation, which can be caused occlusion of parent artery or embolic event(s). To escape from this situation, several rescue methods have been reported. A case with undesirably stretched coil in which another rescue method was used, is presented. When the stretched coil is still located in the coil delivery microcatheter, the stretched coil can be removed safely using a snare and a handmade monorail microcatheter. After a snare is lodged in the handmade monorail microcatheter, the snare is introduced over the coil delivery micorcatheter and located in the distal part of the stretched coil. After then, the handmade monorail microcatheter captures the stretched coil and the snare as one unit. This technique using a handmade monorail microcatheter and a snare can be a good rescue modality for the undesirably stretched coil, still remained within the coil delivery microcatheter.

  12. Introduction of fuzzy logic theorem for quench detection in the superconducting coil system of a Large Helical Device

    International Nuclear Information System (INIS)

    Adachi, Yamato; Ninomiya, Akira; Uriu, Yoshihisa; Ishigohka, Takeshi; Mito, Toshiyuki; Imagawa, Shinsaku; Yanagi, Nagato; Sekiguchi, Haruo; Yamada, Shuichi

    2005-01-01

    We have analyzed the state of the superconducting coil system in a LHD at NIFS (National Institute of Fusion Science) using a fuzzy logic theorem to detect quenching at an early stage. In this method, the 'warning coefficient' of the coil system is calculated. As for the fuzzy variables, 'effective stored heat' in the coil is introduced in addition to the voltage signal in order to improve quench detection and state estimation. The 'effective stored heat' is an integrated value of the heat generated in the coil on the assumption that instantaneous heat in the conductor is continuously cooled by liquid helium. Experiments conducted using the LHD coils confirmed that quench alarm signals can be issued with sufficient lead time before quenching. On the other hand, in the case of small local disturbances, the system shows only a small increase in the caution level. (author)

  13. Effect of pomegranate powder on the heat inactivation of Escherichia coli O157:H4 in ground chicken

    Science.gov (United States)

    Health concerns have led to a search for natural plant-based antimicrobials. Ellagic acid has been shown to have antimicrobial activity against foodborne pathogens. The objective of this study was to assess the effect of a high-ellagic acid commercial pomegranate on the heat resistance of Escherich...

  14. Performance and costs of a roof-sized PV/thermal array combined with a ground coupled heat pump

    NARCIS (Netherlands)

    Bakker, M.; Zondag, H.A.

    2005-01-01

    A photovoltaic/thermal (PVT) panel is a combination of photovoltaic cells with a solar thermal collector, generating solar electricity and solar heat simultaneously. Hence, PVT panels are an alternative for a combination of separate PV panels and solar thermal collectors. A promising system concept,

  15. Updating the Design of the Poloidal Field Coils for the ITER Magnet System

    International Nuclear Information System (INIS)

    Yoshida, K.; Takahashi, Y.; Mitchell, N.; Jong, C.; Bessette, D.

    2006-01-01

    The ITER superconducting coil system consists of 18 Toroidal Field coils, six Poloidal Field (PF) coils, six Central Solenoid (CS) modules, 18 Correction Coils and their feeders. The six PF coils are attached to the TF coil cases through flexible plates or sliding supports allowing radial displacements. The PF coils and CS modules provide suitable magnetic fields for plasma shaping and position control. The PF coils use NbTi superconductor, cooled by supercritical helium. This gives a substantial cost saving compared to Nb 3 Sn and the elimination of a reaction heat treatment greatly simplifies the insulation of such large diameter coils. The cable configuration is 6 sub-cables arranged around a central cooling space. The conductors have a heavy square walled stainless steel jacket. The latest parameters of conductor design are evaluated by analysis of the minimum quench energy and hotspot temperature. The PF coils are self supporting as regards the radial magnetic loads. The vertical loads on each PF coil are transmitted to the TF coil cases. Load transmission is through flexible plates for the PF2 to PF5 coils or sliding supports for the PF1 and PF6 coils with fibreslip bearing surfaces. The supports for the PF winding consist of a set of clamping plates and stud bolts. The shape of the clamping plates has been designed to minimize stresses in the winding pack insulation. Bolts are pre-tensioned to keep pressure between the winding pack and clamping plate. Because of the difficulties in replacing the PF coils, the most unreliable component (the coil insulation) is designed with extra redundancy. There are two insulation layers with a thin metal screen in between. By monitoring the voltage of the intermediate screen, it is possible to detect an incipient short, defined as a short in only one of the two insulation layers. Adjustment of the screen voltage level may allow the shot growth to the stopped once it is detected. Alternately the faulty double pancake must

  16. Coil supporting device in nuclear fusion apparatus

    International Nuclear Information System (INIS)

    Hoshi, Ryo; Imura, Yasuya.

    1974-01-01

    Object: To secure intermediate fittings with a coil fixed thereon by an insulating tape to a fixed body by means of fittings, thereby supporting the coil in a narrow space. Structure: A coil is secured to intermediate fittings by means of an insulating tape, after which the intermediate fittings is mounted on a fixed body through fittings to support the coil in a narrow clearance portion between a plasma sealed vessel and a main coil. (Kamimura, M.)

  17. Voice Coil Percussive Mechanism Concept for Hammer Drill

    Science.gov (United States)

    Okon, Avi

    2009-01-01

    A hammer drill design of a voice coil linear actuator, spring, linear bearings, and a hammer head was proposed. The voice coil actuator moves the hammer head to produce impact to the end of the drill bit. The spring is used to store energy on the retraction and to capture the rebound energy after each impact for use in the next impact. The maximum actuator stroke is 20 mm with the hammer mass being 200 grams. This unit can create impact energy of 0.4 J with 0.8 J being the maximum. This mechanism is less complex than previous devices meant for the same task, so it has less mass and less volume. Its impact rate and energy are easily tunable without changing major hardware components. The drill can be driven by two half-bridges. Heat is removed from the voice coil via CO2 conduction.

  18. Structural support system for a superconducting magnet coil

    International Nuclear Information System (INIS)

    Meuser, R.B.

    1977-01-01

    The purpose of the ESCAR (Experimental Superconducting Accelerator Ring) project, now under way at the Lawrence Berkeley Laboratory, is to gather data and experience in the design and operation of a relatively small synchrotron employing superconducting magnets. Such data are essential to ensure that the design of future large accelerators may proceed in a knowledgeable and responsible manner. One of the many engineering problems associated with a superconducting magnet is the design of the coil suspension system. The coil, maintained at the temperature of liquid helium, must be held rigidly by a structure that does not conduct too much heat into the liquid helium system. The suspension system used on the ESCAR magnets is described. Topics covered include the coil support system requirements, ESCAR magnet support system, and operating experience

  19. Quench and protection characteristics of the GEM test coil

    International Nuclear Information System (INIS)

    Chaniotakis, E.A.; Marston, P.G.

    1994-01-01

    The GEM test coil, will be wound from 70 m of conductor identical to that used in the full scale magnet. The coil configuration will duplicate the field distribution of the full scale magnet and current control will duplicate full scale current decay characteristics. Therefore, quench/protection analysis of this coil will reveal very important information about the behavior of the full scale model. Due to the uncertainty associated with the contact between the cable, the conduit and the sheath, a parametric analysis has been performed in order to determine and bracket the behavior. With no electrical contact the quench evolves normally until, due to heat transfer from the sheath into the cable, the superconductor temperature becomes critical and the entire length becomes normal

  20. A study of photovoltaic/thermal (PVT)-ground source heat pump hybrid system by using fuzzy logic control

    International Nuclear Information System (INIS)

    Andrew Putrayudha, S.; Kang, Eun Chul; Evgueniy, E.; Libing, Y.; Lee, Euy Joon

    2015-01-01

    Renewable Heat Obligation (RHO) implementation in every country becomes an important issue to utilize more renewable energy sources while reducing the usage of fossil fuel. In 2014, South Korea has a target that every commercial building construction that exceeding 10,000 m 2 has to have on-site new & renewable power generation such as combined heat in the beginning of 2016. Photovoltaic/Thermal (PVT) and Geothermal hybrid systems have been introduced in previous research (E.J. Lee et al.) and it showed a great result from its efficiency and also its power consumption for single and multi-building cases. In this paper, Fuzzy Logic control has been applied to optimize the energy consumption of the system. By comparing it with conventional on–off control, fuzzy logic control system shows a better result in reducing primary energy consumption for both heating and cooling systems annually. Two cases were introduced in this paper, GSHP system and PVT–GSHP system with both on–off and fuzzy logic applied respectively. As a result, it shows that fuzzy logic control consumed 13.3% less energy compared with on–off controller for GSHP system annually and 18.3% less energy compared to on–off controller for PVT–GSHP system annually. - Highlights: • Two renewable systems were designed to produce heating, cooling and electricity. • System optimization by applying Fuzzy Logic in terms of energy saving. • Conventional on–off control system vs advance fuzzy logic control system. • Assumption used based on previous research experience, guidelines.

  1. Experiments Demonstrate Geothermal Heating Process

    Science.gov (United States)

    Roman, Harry T.

    2012-01-01

    When engineers design heat-pump-based geothermal heating systems for homes and other buildings, they can use coil loops buried around the perimeter of the structure to gather low-grade heat from the earth. As an alternative approach, they can drill well casings and store the summer's heat deep in the earth, then bring it back in the winter to warm…

  2. Case Study for the ARRA-funded Ground Source Heat Pump (GSHP) Demonstration at Wilders Grove Solid Waste Service Center in Raleigh, NC

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaobing [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Malhotra, Mini [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Xiong, Zeyu [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-11-01

    High initial costs and lack of public awareness of ground-source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy-saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects have been competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This paper highlights the findings of a case study of one of the ARRA-funded GSHP demonstration projects, a distributed GSHP system for providing all the space conditioning, outdoor air ventilation, and 100% domestic hot water to the Wilders Grove Solid Waste Service Center of City of Raleigh, North Carolina. This case study is based on the analysis of measured performance data, construction costs, and simulations of the energy consumption of conventional central heating, ventilation, and air-conditioning (HVAC) systems providing the same level of space conditioning and outdoor air ventilation as the demonstrated GSHP system. The evaluated performance metrics include the energy efficiency of the heat pump equipment and the overall GSHP system, pumping performance, energy savings, carbon emission reductions, and cost-effectiveness of the GSHP system compared with conventional HVAC systems. This case study also identified opportunities for reducing uncertainties in the performance evaluation and improving the operational efficiency of the demonstrated GSHP system.

  3. Application of the integrated blanket-coil concept (IBC) to fusion reactors

    International Nuclear Information System (INIS)

    Embrechts, M.J.; Steiner, D.; Mohanti, R.; Duggan, W.

    1987-01-01

    A novel concept is proposed for combining the blanket and coil functions of a fusion reactor into a single component and several unique applications to fusion reactor embodiments are identified. The proposed concept takes advantage of the fact that lithium is a good electrical conductor in addition to being a unique tritium-breeding material capable of energy recovery and transport at high temperatures. This concept, designated the ''integrated-blanket-coil (IBC) concept'' has the potential for: allowing fusion reactor embodiments which are easier to maintain; making fusion reactors more compact with an intrinsic ultra-high mass power density (net kW/sub E//metric tonne); and enhancing the tritium breeding potential for special coil applications such as ohmic heating and bean identation. By assuming a sandwich construction for the IBC walls (i.e., a layered combination of a thin wall of structural material, insulator and structural materials) the magnetohydrodynamic (MHD)-induced pressure drops and associated pressure stresses are modest and well below design limits. Possible unique applications of the IBC concept have been investigated and include the IBC concept applied to the poloidal field (PF) coils, toroidal field (TF) coils, divertor coils, ohmic heating (OH) coils, and identation coils for bean shaping

  4. Test results of the SMES model coil. Cool-down and thermal characteristics

    International Nuclear Information System (INIS)

    Hamada, Kazuya; Kato, Takashi; Kawano, Katsumi

    1998-01-01

    A model coil of a superconducting magnetic energy storage (SMES) device, which is a forced-cooled Nb-Ti coil, has been fabricated and a performance test at cryogenic temperatures has been carried out. The SMES model coil is composed of 4 dual pancakes and its total weight is 4.5 t. The applied conductors are cable-in-conduit conductors cooled by supercritical helium (SHe) at 4.5 K and 0.7 MPa. SHe is supplied to the SMES model coil and the structure by a reciprocating bellows pump. The test facility is located at the International Thermonuclear Experimental Reactor (ITER) common test facility, was constructed for the testing of an ITER central solenoid model coil. In the experiments, cool-down was finished within 10 days under controlled temperature differences in the SMES model coil. During cool-down and 4.5 K operation, pressure drop characteristics of the conductor were measured and the friction factor estimated. The pressure drop characteristics of the SMES model coil were in good agreement with those of the previous cable-in-conduit conductor. During static operation without current, the heat load and refrigerator operation conditions were measured. The heat load of the SMES model coil is 7.5 W, which is within the expected value. (author)

  5. Stability tests of the Westinghouse coil in the International Fusion Superconducting Magnet Test Facility

    International Nuclear Information System (INIS)

    Dresner, L.; Fehling, D.T.; Lubell, M.S.; Lue, J.W.; Luton, J.N.; McManamy, T.J.; Shen, S.S.; Wilson, C.T.

    1987-09-01

    The Westinghouse coil is one of three forced-flow coils in the six-coil toroidal array of the International Fusion Superconducting Magnet Test Facility at Oak Ridge National Laboratory. It is wound with an 18-kA, Nb 3 Sn/Cu, cable-in-conduit superconductor structurally supported by aluminum plates and cooled by 4-K, 15-atm supercritical helium. The coil is instrumented to permit measurement of helium temperature, pressure, and flow rate; structure temperature and strain; field; and normal zone voltage. A resistive heater has been installed to simulate nuclear heating, and inductive heaters have been installed to facilitate stability testing. The coil has been tested both individually and in the six-coil array. The tests covered charging to full design current and field, measuring the current-sharing threshold temperature using the resistive heaters, and measuring the stability margin using the pulsed inductive heaters. At least one section of the conductor exhibits a very broad resistive transition (resistive transition index = 4). The broad transition, though causing the appearance of voltage at relatively low temperatures, does not compromise the stability margin of the coil, which was greater than 1.1 J/cm 3 of strands. In another, nonresistive location, the stability margin was between 1.7 and 1.9 J/cm 3 of strands. The coil is completely stable in operation at 100% design current in both the single- and six-coil modes

  6. Modelling and Optimization of Four-Segment Shielding Coils of Current Transformers.

    Science.gov (United States)

    Gao, Yucheng; Zhao, Wei; Wang, Qing; Qu, Kaifeng; Li, He; Shao, Haiming; Huang, Songling

    2017-05-26

    Applying shielding coils is a practical way to protect current transformers (CTs) for large-capacity generators from the intensive magnetic interference produced by adjacent bus-bars. The aim of this study is to build a simple analytical model for the shielding coils, from which the optimization of the shielding coils can be calculated effectively. Based on an existing stray flux model, a new analytical model for the leakage flux of partial coils is presented, and finite element method-based simulations are carried out to develop empirical equations for the core-pickup factors of the models. Using the flux models, a model of the common four-segment shielding coils is derived. Furthermore, a theoretical analysis is carried out on the optimal performance of the four-segment shielding coils in a typical six-bus-bars scenario. It turns out that the "all parallel" shielding coils with a 45° starting position have the best shielding performance, whereas the "separated loop" shielding coils with a 0° starting position feature the lowest heating value. Physical experiments were performed, which verified all the models and the conclusions proposed in the paper. In addition, for shielding coils with other than the four-segment configuration, the analysis process will generally be the same.

  7. Design and Optimization of a 3-Coil Inductive Link for Efficient Wireless Power Transmission.

    Science.gov (United States)

    Kiani, Mehdi; Jow, Uei-Ming; Ghovanloo, Maysam

    2011-07-14

    Inductive power transmission is widely used to energize implantable microelectronic devices (IMDs), recharge batteries, and energy harvesters. Power transfer efficiency (PTE) and power delivered to the load (PDL) are two key parameters in wireless links, which affect the energy source specifications, heat dissipation, power transmission range, and interference with other devices. To improve the PTE, a 4-coil inductive link has been recently proposed. Through a comprehensive circuit based analysis that can guide a design and optimization scheme, we have shown that despite achieving high PTE at larger coil separations, the 4-coil inductive links fail to achieve a high PDL. Instead, we have proposed a 3-coil inductive power transfer link with comparable PTE over its 4-coil counterpart at large coupling distances, which can also achieve high PDL. We have also devised an iterative design methodology that provides the optimal coil geometries in a 3-coil inductive power transfer link. Design examples of 2-, 3-, and 4-coil inductive links have been presented, and optimized for 13.56 MHz carrier frequency and 12 cm coupling distance, showing PTEs of 15%, 37%, and 35%, respectively. At this distance, the PDL of the proposed 3-coil inductive link is 1.5 and 59 times higher than its equivalent 2- and 4-coil links, respectively. For short coupling distances, however, 2-coil links remain the optimal choice when a high PDL is required, while 4-coil links are preferred when the driver has large output resistance or small power is needed. These results have been verified through simulations and measurements.

  8. Application of high-temperature superconducting coil for internal ring devices

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Yuichi [High Temperature Plasma Center, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan)]. E-mail: ogawa@ppl.k.u-tokyo.ac.jp; Morikawa, Junji [High Temperature Plasma Center, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan); Mito, Toshiyuki [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan); Yanagi, Nagato [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan); Iwakuma, Masataka [Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

    2006-11-15

    A high-temperature superconducting (HTS) coil is applied for plasma confinement devices, where plasma is confined with a magnetic field of a floating HTS coil. The internal coil device mini-RT with a BSCCO tape has been constructed, in which the coil major radius and magnetomotive force are 0.15 m and 50 kA, respectively. The coil is cooled to 20 K with a helium gas by using a demountable transfer tube and check valve system. The coil current is directly excited by the external power supply with demountable electrodes. To reduce the heat load, the electrodes were cooled with liquid nitrogen. The levitation experiment of the HTS coil has been carried out. The position of the HTS coil is measured by laser sensors, and is feedback-controlled with the levitation coil current. We have succeeded in levitating the HTS coil during 1 h with accuracy of less than 20 {mu}m. The magnetic field strength near the internal coil is around 0.1 T, and a radio-frequency wave of 2.45 GHz is applied for the plasma production. At the floating condition of the HTS coil, a high-density plasma with more than 10{sup 17} m{sup -3}, which is higher than the cut-off density of a 2.45 GHz microwave, has been produced. A new device RT-1 with a major radius of 0.25 m and a magnetomotive force of 250 kA is under construction, and a persistent current has been demonstrated. The feasibility on YBCO tape is briefly discussed.

  9. Function and operation of the Doublet III E-coil vacuum breaker system

    International Nuclear Information System (INIS)

    Callis, R.W.; Jackson, G.; DeGrassie, J.; Peterson, P.; LeVine, F.

    1979-11-01

    The ohmic heating system for the Doublet III fusion research device at General Atomic is required to provide the voltage for the initial breakdown phase (there is no preionization) along with the energy to drive the plasma current to a value of 2.5 MA or greater. This requires a peak one turn voltage of 250 volts (16 kV across coil terminals) and a magnetic flux swing of 5 volt-seconds (peak coil current of 110 kA). This voltage and flux swing is accomplished by reverse biasing the ohmic heating coil (E-coil) where, upon reaching a value of 110 ka the coil current is interrupted and commutated into a RC network producing 16 kV across the coil. The interrruption of the E-coil current is accomplished by the use of an array of vacuum circuit breakers (VCB's) and a counter plus network. A description is given of the ohmic heating circuit and the performance of the vacuum circuit breaker array and its counter pulse system

  10. Design of a coil sensor for time domain electromagnetic system for uranium exploration

    International Nuclear Information System (INIS)

    Keshwani, R.T.; Bhattacharya, S.

    2011-01-01

    Time domain electromagnetic system is used for exploration of deep seated deposits under the Earth surface. The basic principle is to set up eddy currents in conductors using pulsed excited transmitter coil during on time of a pulse. The decay time of eddy currents during off time of a pulse is a function conductivity, permeability and depth of conductor located under the Earth surface. The technology is being developed to carry out exploration of mineral deposits (basically uranium) under the Earth surface. The decay of eddy currents is eddy using J coil sensor located coplanar with the transmitter coil. The depth upto which successful exploration can be carried is strong function of design of receiver coil. The design parameters include number of turns, bandwidth, stray capacitance and resistance of a coil. This paper describes various designs tried out and their characterization results. Field results for a ground based system developed are also described. (author)

  11. Thermal analysis of laser welding for ITER correction coil case

    Energy Technology Data Exchange (ETDEWEB)

    Fang, C., E-mail: fangchao@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 200031 (China); Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta (Finland); Song, Y.T.; Wu, W.Y.; Wei, J.; Xin, J.J. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 200031 (China); Wu, H.P.; Salminen, A. [Lappeenranta University of Technology, Skinnarilankatu 34, 53850 Lappeenranta (Finland)

    2015-11-15

    Highlights: • Morphology of simulated heat source is found to be close to the welded joint sample. • The FEA temperature distribution shows good agreement with experimental measurements. • Laser welding process used on ITER correction coil case will not harm the winding pack. - Abstract: This paper presents the simulation results of 3D finite element analysis (FEA) of laser welding processes for the ITER correction coil case welding; predicts the temperature distribution and compares it with the experimental result to evaluate the impact to the properties of winding pack during the welding process. A specimen of coil case was modeled and simulated by using specialized welding simulation software SYSWELD, Modeling used austenitic stainless steel 316LN as the specimen material and a 3D Conical Gaussian was used as a heat source model. A plate sample was welded before the FE modeling in order to obtain the laser welding parameters and the Gaussian parameters of molten pool. To verify the simulation results, a coil case sample was welded using laser welding with welding parameters that matched the model, and the corresponding temperature values were measured using thermocouples. Compared with the FEA results, it was found that the FEA temperature distribution shows good agreement with the experimental measurements and the laser welding process will not harm the winding pack.

  12. CCHMM_PROF: a HMM-based coiled-coil predictor with evolutionary information

    DEFF Research Database (Denmark)

    Bartoli, Lisa; Fariselli, Piero; Krogh, Anders

    2009-01-01

    tools are available for predicting coiled-coil domains in protein sequences, including those based on position-specific score matrices and machine learning methods. RESULTS: In this article, we introduce a hidden Markov model (CCHMM_PROF) that exploits the information contained in multiple sequence...... alignments (profiles) to predict coiled-coil regions. The new method discriminates coiled-coil sequences with an accuracy of 97% and achieves a true positive rate of 79% with only 1% of false positives. Furthermore, when predicting the location of coiled-coil segments in protein sequences, the method reaches...

  13. Transient voltage oscillations in coils

    International Nuclear Information System (INIS)

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated

  14. Rotating Arc Jet Test Model: Time-Accurate Trajectory Heat Flux Replication in a Ground Test Environment

    Science.gov (United States)

    Laub, Bernard; Grinstead, Jay; Dyakonov, Artem; Venkatapathy, Ethiraj

    2011-01-01

    Though arc jet testing has been the proven method employed for development testing and certification of TPS and TPS instrumentation, the operational aspects of arc jets limit testing to selected, but constant, conditions. Flight, on the other hand, produces timevarying entry conditions in which the heat flux increases, peaks, and recedes as a vehicle descends through an atmosphere. As a result, we are unable to "test as we fly." Attempts to replicate the time-dependent aerothermal environment of atmospheric entry by varying the arc jet facility operating conditions during a test have proven to be difficult, expensive, and only partially successful. A promising alternative is to rotate the test model exposed to a constant-condition arc jet flow to yield a time-varying test condition at a point on a test article (Fig. 1). The model shape and rotation rate can be engineered so that the heat flux at a point on the model replicates the predicted profile for a particular point on a flight vehicle. This simple concept will enable, for example, calibration of the TPS sensors on the Mars Science Laboratory (MSL) aeroshell for anticipated flight environments.

  15. Large coil program support structure conceptual design

    International Nuclear Information System (INIS)

    Litherland, P.S.

    1977-01-01

    The purpose of the Large Coil Program (LCP) is to perform tests on both pool boiling and force cooled superconducting toroidal field coils. The tests will attempt to approximate conditions anticipated in an ignition tokamak. The test requirements resulted in a coil support design which accommodates up to six (6) test coils and is mounted to a structure capable of resisting coil interactions. The steps leading to the present LCP coil support structure design, details on selected structural components, and the basic assembly sequence are discussed

  16. Heat pumps: heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Pielke, R

    1976-01-01

    The author firstly explains in a general manner the functioning of the heat pump. Following a brief look at the future heat demand and the possibilities of covering it, the various methods of obtaining energy (making use of solar energy, ground heat, and others) and the practical applications (office heating, swimming pool heating etc.) are explained. The author still sees considerable difficulties in using the heat pump at present on a large scale. Firstly there is not enough maintenance personnel available, secondly the electricity supply undertakings cannot provide the necessary electricity on a wide basis without considerable investments. Other possibilities to save energy or to use waste energy are at present easier and more economical to realize. Recuperative and regenerative systems are described.

  17. Large Coil Program magnetic system design study

    International Nuclear Information System (INIS)

    Moses, S.D.; Johnson, N.E.

    1977-01-01

    The primary objective of the Large Coil Program (LCP) is to demonstrate the reliable operation of large superconducting coils to provide a basis for the design principles, materials, and fabrication techniques proposed for the toroidal magnets for the THE NEXT STEP (TNS) and other future tokamak devices. This paper documents a design study of the Large Coil Test Facility (LCTF) in which the structural response of the Toroidal Field (TF) Coils and the supporting structure was evaluated under simulated reactor conditions. The LCP test facility structural system consists of six TF Coils, twelve coil-to-coil torsional restraining beams (torque rings), a central bucking post with base, and a Pulse Coil system. The NASTRAN Finite Element Structural Analysis computer Code was utilized to determine the distribution of deflections, forces, and stresses for each of the TF Coils, torque rings, and the central bucking post. Eleven load conditions were selected to represent probable test operations. Pulse Coils suspended in the bore of the test coil were energized to simulate the pulsed field environment characteristic of the TNS reactor system. The TORMAC Computer Code was utilized to develop the magnetic forces in the TF Coils for each of the eleven loading conditions examined, with or without the Pulse Coils energized. The TORMAC computer program output forces were used directly as input load conditions for the NASTRAN analyses. Results are presented which demonstrate the reliability of the LCTF under simulated reactor operating conditions

  18. Effect of the heat curing on strength development of self-compacting mortars containing calcined silt of dams and Ground Brick Waste

    Directory of Open Access Journals (Sweden)

    B. Safi

    2013-01-01

    Full Text Available The strength development of self-compacting mortars (SCM containing calcined silt (CS and ground brick waste (GWB was investigated. The variables are the nature of addition (CS and GWB in the binder and the heat curing at different temperatures (20 ºC and 60 ºC at 7 and 14 days of curing. Two temperatures 20 and 60 ºC were applied to samples with intermediate levels (depending on the drying method applied to precast for 18 hours in total. In this study, a Portland cement (CEMII, Calcined silt (750 ºC for 5 hours, ground waste brick, were used in the binders of SCM. The results show that the compressive strength to 14 days of mortars, increases with annealing (60 ºC compared to that measured at 20 ºC. Also, values of compressive strength of mortars at 14 days that are close to those obtained without 28 days curing treatment. Indeed, a strength gain of about 20.5% and 27.3% was obtained respectively for the SCM with GWB and the SCM with CS. However, a small change in mass recorded for both types of mortars.

  19. Modelling flow and heat transfer through unsaturated chalk - Validation with experimental data from the ground surface to the aquifer

    Science.gov (United States)

    Thiéry, Dominique; Amraoui, Nadia; Noyer, Marie-Luce

    2018-01-01

    During the winter and spring of 2000-2001, large floods occurred in northern France (Somme River Basin) and southern England (Patcham area of Brighton) in valleys that are developed on Chalk outcrops. The floods durations were particularly long (more than 3 months in the Somme Basin) and caused significant damage in both countries. To improve the understanding of groundwater flooding in Chalk catchments, an experimental site was set up in the Hallue basin, which is located in the Somme River Basin (France). Unsaturated fractured chalk formation overlying the Chalk aquifer was monitored to understand its reaction to long and heavy rainfall events when it reaches a near saturation state. The water content and soil temperature were monitored to a depth of 8 m, and the matrix pressure was monitored down to the water table, 26.5 m below ground level. The monitoring extended over a 2.5-year period (2006-2008) under natural conditions and during two periods when heavy, artificial infiltration was induced. The objective of the paper is to describe a vertical numerical flow model based on Richards' equation using these data that was developed to simulate infiltrating rainwater flow from the ground surface to the saturated aquifer. The MARTHE computer code, which models the unsaturated-saturated continuum, was adapted to reproduce the monitored high saturation periods. Composite constitutive functions (hydraulic conductivity-saturation and pressure-saturation) that integrate the increase in hydraulic conductivity near saturation and extra available porosity resulting from fractures were introduced into the code. Using these composite constitutive functions, the model was able to accurately simulate the water contents and pressures at all depths over the entire monitored period, including the infiltration tests. The soil temperature was also accurately simulated at all depths, except during the infiltrations tests, which contributes to the model validation. The model was used

  20. Coil Design for High Misalignment Tolerant Inductive Power Transfer System for EV Charging

    Directory of Open Access Journals (Sweden)

    Kafeel Ahmed Kalwar

    2016-11-01

    Full Text Available The inductive power transfer (IPT system for electric vehicle (EV charging has acquired more research interest in its different facets. However, the misalignment tolerance between the charging coil (installed in the ground and pick-up coil (mounted on the car chassis, has been a challenge and fundamental interest in the future market of EVs. This paper proposes a new coil design QDQ (Quad D Quadrature that maintains the high coupling coefficient and efficient power transfer during reasonable misalignment. The QDQ design makes the use of four adjacent circular coils and one square coil, for both charging and pick-up side, to capture the maximum flux at any position. The coil design has been modeled in JMAG software for calculation of inductive parameters using the finite element method (FEM, and its hardware has been tested experimentally at various misaligned positions. The QDQ coils are shown to be capable of achieving good coupling coefficient and high efficiency of the system until the misalignment displacement reaches 50% of the employed coil size.

  1. Finite element coiled cochlea model

    Science.gov (United States)

    Isailovic, Velibor; Nikolic, Milica; Milosevic, Zarko; Saveljic, Igor; Nikolic, Dalibor; Radovic, Milos; Filipović, Nenad

    2015-12-01

    Cochlea is important part of the hearing system, and thanks to special structure converts external sound waves into neural impulses which go to the brain. Shape of the cochlea is like snail, so geometry of the cochlea model is complex. The simplified cochlea coiled model was developed using finite element method inside SIFEM FP7 project. Software application is created on the way that user can prescribe set of the parameters for spiral cochlea, as well as material properties and boundary conditions to the model. Several mathematical models were tested. The acoustic wave equation for describing fluid in the cochlea chambers - scala vestibuli and scala timpani, and Newtonian dynamics for describing vibrations of the basilar membrane are used. The mechanical behavior of the coiled cochlea was analyzed and the third chamber, scala media, was not modeled because it does not have a significant impact on the mechanical vibrations of the basilar membrane. The obtained results are in good agreement with experimental measurements. Future work is needed for more realistic geometry model. Coiled model of the cochlea was created and results are compared with initial simplified coiled model of the cochlea.

  2. BPX toroidal field coil design

    International Nuclear Information System (INIS)

    Heitzenvoeder, D.J.

    1992-01-01

    This paper reports on the toroidal field (TF) coil system of the Burning Plasma Experiment (BPX) which consists of (18) beryllium copper magnets arrayed in a wedged configuration with a major radius of 2.6 meters and a field strength capability on axis of 9.0 Tesla. The toroidal array is constructed from six (3)-coil modules to facilitate remote recovery in the event of a magnet failure after nuclear activation precludes hands-on servicing. The magnets are of a modified Bitter plate design with partial cases of type 316-LN stainless steel welded with Inconel 182 weld wire. The coil turn plates are fabricated from CDA C17510 beryllium copper with optimized mechanical, thermal, and electrical characteristics. joints within the turns and between turns are made by welding with C17200 filler wire. Cryogenic cooling is employed to reduce power dissipation and to enhance performance. The magnets are cooled between experimental pulses by pressurized liquid nitrogen flowing through channels in the edges of the coil turns. This arrangement makes possible one full-power pulse per hour. Electrical insulation consists of polyimide-glass sheets bonded in place with vacuum-pressure impregnated epoxy/glass

  3. Demonstration poloidal coil test facility

    International Nuclear Information System (INIS)

    Sato, Masahiko; Kawano, Katumi; Tada, Eisuke

    1989-01-01

    A new compact cryogenic cold compressor was developed by Japan Atomic Energy Research Institute (JAERI) in collaboration with Isikawajima-Harima Heavy Industries Co., Ltd. (IHI) in order to produce the supercritical helium below 4.2 K for Demonstration Poloidal Coils (DPC) which are forced-flow cooled type superconducting pulse coils. This compressor is one of key components for DPC test facility. The cold compressor reduces pressure in liquid helium bath, which contains liquid helium of around 3,000 l, down to 0.5 atm efficiently. Consequently, supercritical helium down to 3.5 K is produced and supplied to the DPC coils. A centrifugal compressor with dynamic gas bearing is selected as a compressor mechanism to realize high adiabatic efficiency and large flow rate. In this performance tests, the compressor was operated for 220 h at saturated condition from 0.5 to 1.0 atm without any failure. High adiabatic efficiency (more than 60 %) is achieved with wide flow range (25-65 g/s) and the design value is fully satisfied. The compressor can rotate up to 80,000 rpm at maximum then the coil supply temperature of supercritical helium is 3.5 K. (author)

  4. Open-Coil Retraction Spring

    Directory of Open Access Journals (Sweden)

    Pavankumar Janardan Vibhute

    2011-01-01

    Full Text Available Sliding mechanic has become a popular method for space closure with developments in preadjusted edgewise appliance. Furthermore, various space closing auxiliaries have been developed and evaluated extensively for their clinical efficiency. Their effectiveness enhanced with optimum force magnitude and low-load deflection rate (LDR/f