Heat integration and analysis of decarbonised IGCC sites

Energy Technology Data Exchange (ETDEWEB)

Ng, K.S.; Lopez, Y.; Campbell, G.M.; Sadhukhan, J. [University of Manchester, Manchester (United Kingdom). School of Chemical Engineering & Analytical Science

2010-02-15

Integrated gasification combined cycle (IGCC) power generation systems have become of interest due to their high combined heat and power (CHP) generation efficiency and flexibility to include carbon capture and storage (CCS) in order to reduce CO{sub 2} emissions. However, IGCC's biggest challenge is its high cost of energy production. In this study, decarbonised coal IGCC sites integrated with CCS have been investigated for heat integration and economic value analyses. It is envisaged that the high energy production cost of an IGCC site can be offset by maximising site-wide heat recovery and thereby improving the cost of electricity (COE) of CHP generation. Strategies for designing high efficiency CHP networks have been proposed based on thermodynamic heuristics and pinch theory. Additionally, a comprehensive methodology to determine the COE from a process site has been developed. In this work, we have established thermodynamic and economic comparisons between IGCC sites with and without CCS and a trade-off between the degree of decarbonisation and the COE from the heat integrated IGCC sites. The results show that the COE from the heat integrated decarbonised IGCC sites is significantly lower compared to IGCC sites without heat integration making application of CCS in IGCC sites economically competitive.

Heat transfer of liquid-metal magnetohydrodynamic flow with internal heat generation

International Nuclear Information System (INIS)

Kumamaru, Hiroshige; Kurita, Kazuhisa; Kodama, Satoshi

2000-01-01

Numerical calculations on heat transfer of a magnetohydrodynamic (MHD) flow with internal heat generation in a rectangular channel have been performed for the cases of very-large Hartmann numbers, finite wall conductivities and small aspect ratio (i.e. small length ratios of the channel side perpendicular to the applied magnetic field and the side parallel to the field), simulating typical conditions for a fusion-reactor blanket. The Nusselt numbers of the MHD flow in rectangular channels with aspect ratios of 1/10 to 1/40 for Hartmann numbers of ∼5 x 10 5 become ∼10 times higher than those for the corresponding flow under no magnetic field. The Nusselt number becomes higher as the internal heat generation rate increases as far as the heat generation rates in a fusion reactor blanket are considered. (author)

Experimental and analytical study of natural-convection heat transfer of internally heated liquids

International Nuclear Information System (INIS)

Green, G.A.

1982-08-01

Boundary heat transfer from a liquid pool with a uniform internal heat source to a vertical or inclined boundary was investigated. The experiments were performed in an open rectangular liquid pool in which the internal heat source was generated by electrical heating. The local heat flux was measured to a boron nitride test wall which was able to be continuously inclined from vertical. Gold plated microthermocouples of 0.01 inch outside diameter were developed to measure the local surface temperature, both front and back, of the boron nitride. The local heat flux and, thus, the local heat transfer coefficient was measured at nineteen locations along the vertical axis of the test plate. A theoretical analysis of the coupled nonlinear boundary layer equations was performed. The parametric effect of the Prandtl number and the dimensionless wall temperature on the boundary heat transfer were investigated When the analytical model was used to calculate the boundary heat transfer data, agreement was achieved with the experimental data within 3% for the local heat transfer and within 2% for the average heat transfer

Thermal resistance of a convectively cooled plate with applied heat flux and variable internal heat generation

International Nuclear Information System (INIS)

Venkataraman, N.S.; Cardoso, H.P.; Oliveira Filho, O.B. de

1981-01-01

The conductive heat transfer in a rectangular plate with nonuniform internal heat generation, with one end convectively cooled and a part of the opposite end subjected to external heat flux is considered. The remaining part of this end as well as the other two sides are thermally insulated. The governing differential equation is solved by a finite difference scheme. The variation of the thermal resistance with Biot modulus, the plate geometry, the internal heat generation parameter and the type of profile of internal heat generation is discussed. (author) [pt

Integrated Heat Exchange For Recuperation In Gas Turbine Engines

Science.gov (United States)

2016-12-01

combustion engines conduct heat transfer in the exhaust system. The exhaust valves have hollow stems containing sodium, which act as heat pipes with...is the use of heat pipes in internal combustion engines . Internal combustion engines have combustion chambers with temperatures as high as 2700 K...accomplished using evaporative heat pipes . This study explores the feasibility of embedding this heat exchange system within engines using a

Optimum heat storage design for heat integrated multipurpose batch plants

CSIR Research Space (South Africa)

Stamp, J

2011-01-01

Full Text Available procedure is presented tha journal homepage: www All rights reserved. ajozi T, Optimum heat storage grated multipurpose batch plants , South Africa y usage in multipurpose batch plants has been in published literature most present methods, time... � 2pL?u?kins ? 1 h3A3?u?cu?U (36) The internal area for heat loss by convection from the heat transfer medium is given by Constraint (37) and the area for convective heat transfer losses to the environment is given in Constraint (38). A1?u? ? 2...

Optimal Placement of A Heat Pump in An Integrated Power and Heat Energy System

DEFF Research Database (Denmark)

Klyapovskiy, Sergey; You, Shi; Bindner, Henrik W.

2017-01-01

With the present trend towards Smart Grids and Smart Energy Systems it is important to look for the opportunities for integrated development between different energy sectors, such as electricity, heating, gas and transportation. This paper investigates the problem of optimal placement of a heat...... pump – a component that links electric and heating utilities together. The system used to demonstrate the integrated planning approach has two neighboring 10kV feeders and several distribution substations with loads that require central heating from the heat pump. The optimal location is found...

Integrated Heat Air & Moisture Modeling and control

NARCIS (Netherlands)

Schijndel, van A.W.M.

2007-01-01

The paper presents a recently developed Heat Air & Moisture Laboratory in SimuLink. The simulation laboratory facilitates the integration of the following models: (1) a whole building model; (2) Heating Venting and Air-Conditioning and primary systems; (3) 2D indoor airflow, 3D Heat Air & Moisture

Heat transfer 1990. Proceedings of the ninth international heat transfer conference

International Nuclear Information System (INIS)

Hetsroni, G.

1990-01-01

This book contains the proceedings of the Ninth International Heat Transfer Conference. Included in Volume 3 are the following chapters: Refrigerant vapor condensation on a horizontal tube bundle. Local heat transfer in a reflux condensation inside a closed two-phase thermosyphon and surface temperature by means of a pulsed photothermal effects

Postaccident heat removal. II. Heat transfer from an internally heated liquid to a melting solid

International Nuclear Information System (INIS)

Faw, R.E.; Baker, L. Jr.

1976-01-01

Microwave heating has been used in studies of heat transfer from a horizontal layer of internally heated liquid to a melting solid. Experiments were designed to simulate heat transfer and meltthrough processes of importance in the analysis of postaccident heat removal capabilities of nuclear reactors. Glycerin, heated by 2.45-GHz microwave radiation, was used to simulate molten fuel. Paraffin wax was used to simulate a melting barrier confining the fuel. Experimentally measured heat fluxes and melting rates were consistent with a model based on downward heat transfer by conduction through a stagnant liquid layer and upward heat transfer augmented by natural convection. Melting and displacement of the barrier material occurred by upward-moving droplets randomly distributed across the melting surface. Results indicated that the melting and displacement process had no effect on the heat transfer process

Internally Heated Screw Pyrolysis Reactor (IHSPR) heat transfer performance study

Science.gov (United States)

Teo, S. H.; Gan, H. L.; Alias, A.; Gan, L. M.

2018-04-01

1.5 billion end-of-life tyres (ELT) were discarded globally each year and pyrolysis is considered the best solution to convert the ELT into valuable high energy-density products. Among all pyrolysis technologies, screw reactor is favourable. However, conventional screw reactor risks plugging issue due to its lacklustre heat transfer performance. An internally heated screw pyrolysis reactor (IHSPR) was developed by local renewable energy industry, which serves as the research subject for heat transfer performance study of this particular paper. Zero-load heating test (ZLHT) was first carried out to obtain the operational parameters of the reactor, followed by the one dimensional steady-state heat transfer analysis carried out using SolidWorks Flow Simulation 2016. Experiments with feed rate manipulations and pyrolysis products analyses were conducted last to conclude the study.

Integrated conjugate heat transfer analysis method for in-vessel retention with external reactor vessel cooling - 15477

International Nuclear Information System (INIS)

Park, J.W.; Bae, J.H.; Seol, W.C.

2015-01-01

An integrated conjugate heat transfer analysis method for the thermal integrity of a reactor vessel under external reactor vessel cooling conditions is developed to resolve light metal layer focusing effect issue. The method calculates steady-state 3-dimensional temperature distribution of a reactor vessel using coupled conjugate heat transfer between in-vessel 3-layered stratified corium (metallic pool, oxide pool and heavy metal) and polar-angle dependent boiling heat transfer at the outer surface of a reactor vessel. The 3-layer corium heat transfer model is utilizing lumped-parameter thermal-resistance circuit method and ex-vessel boiling regimes are parametrically considered. The thermal integrity of a reactor vessel is addressed in terms of un-molten thickness profile. The vessel 3-dimensional heat conduction is validated against a commercial code. It is found that even though the internal heat flux from the metal layer goes far beyond critical heat flux (CHF) the heat flux from the outermost nodes of the vessel may be maintained below CHF due to massive vessel heat diffusion. The heat diffusion throughout the vessel is more pronounced for relatively low heat generation rate in an oxide pool. Parametric calculations are performed considering thermal conditions such as peak heat flux from a light metal layer, heat generation in an oxide pool and external boiling conditions. The major finding is that the most crucial factor for success of in-vessel retention is not the mass of the molten light metal above the oxide pool but the heat generation rate inside the oxide pool and the 3-dimensional vessel heat transfer provides a much larger minimum vessel wall thickness. (authors)

Heat integrated ethanol dehydration flowsheets

Energy Technology Data Exchange (ETDEWEB)

Hutahaean, L.S.; Shen, W.H.; Brunt, V. Van [Univ. of South Carolina, Columbia, SC (United States)

1995-04-01

zA theoretical evaluation of heat-integrated heterogeneous-azeotropic ethanol-water distillation flowsheets is presented. Simulations of two column flowsheets using several different hydrocarbon entrainers reveal a region of potential heat integration and substantial reduction in operating energy. In this paper, methods for comparing hydrocarbon entrainers are shown. Two aspects of entrainers are related to operating and capital costs. The binary azeotropic composition of the entrainer-ethanol mixture is related to the energy requirements of the flowsheet. A temperature difference in the azeotrophic column is related to the size of the column and overall process staging requirements. Although the hydrophobicity of an entrainer is essential for specification of staging in the dehydration column, no substantial increase in operating energy results from an entrainer that has a higher water content. Likewise, liquid-liquid equilibria between several entrainer-ethanol-water mixtures have no substantial effect on either staging or operation. Rather, increasing the alcohol content of the entrainer-ethanol azeotrope limits its recovery in the dehydration column, and increases the recycle and reflux streams. These effects both contribute to increasing the separation energy requirements and reducing the region of potential heat integration. A cost comparison with a multieffect extractive distillation flowsheet reveals that the costs are comparable; however, the extractive distillation flowsheet is more cost effective as operating costs increase.

Steady, three-dimensional, internally heated convection

International Nuclear Information System (INIS)

Schubert, G.; Glatzmaier, G.A.; Travis, B.

1993-01-01

Numerical calculations have been carried out of steady, symmetric, three-dimensional modes of convection in internally heated, infinite Prandtl number, Boussinesq fluids at a Rayleigh number of 1.4x10 4 in a spherical shell with inner/outer radius of 0.55 and in a 3x3x1 rectangular box. Multiple patterns of convection occur in both geometries. In the Cartesian geometry the patterns are dominated by cylindrical cold downflows and a broad hot upwelling. In the spherical geometry the patterns consist of cylindrical cold downwellings centered either at the vertices of a tetrahedron or the centers of the faces of a cube. The cold downflow cylinders are immersed in a background of upwelling within which there are cylindrical hot concentrations (plumes) and hot halos around the downflows. The forced hot upflow return plumes of internally heated spherical convection are fundamentally different from the buoyancy-driven plumes of heated from below convection

Dissipation of heat from building integrated PV

Energy Technology Data Exchange (ETDEWEB)

Taylor, C.M.L.

2001-07-01

The objectives of the project were to investigate methods for improving heat transfer and the reflection of heat from PV modules in building integrated situations and to develop the design of a building integrated PV element with improved heat transfer characteristics, with the aim of reducing the operating temperature of the PV cells. The prototypes developed for improving heat transfer have only shown small reductions in the PV cell operating temperature and these results have not been fully quantified due to problems associated with experimental testing. The improvement in the overall electrical performance of PV modules operating at lower temperatures is consequently even smaller. As a result, none of the prototypes can be considered to be economically viable. Based upon the theoretical and experimental results of this work, it is the recommendation of this project that no further work be conducted in improving BIPV performance through improved heat transfer of BIPV. (Author)

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

OpenAIRE

Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

2016-01-01

An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is d...

Experimental study on local heat transfer characteristics of porous media with internal heat source

International Nuclear Information System (INIS)

Zan Yuanfeng; Wang Taotao; Xiao Zejun; Wang Fei; Huang Yanping

2008-01-01

Model of porous media with internal heat source is established. The model uses water as flowing media, and the stainless steel test section is packed with steel spheres in manner of regular triangle, respectively. The armoured resistance wire is inserted inside the steel sphere. On the basis of the experimental model, many parameters of the local heat transfer characteristics including current velocity and wall temperature of steel sphere are measured. The experimental results show that the coefficient of heat transfer scarcely changes with pressure. The coefficient of heat transfer increases with the surface heat flux of steel sphere. When raising the inlet temperature of the cooling water, the coefficient of heat transfer presents the descending trend. In addition, the influence of entrance effect on heat transfer is discovered in the experiment, which is much less than the liquid flow in the light tube. After experiment data are analyzed and processed, the relation model of heat transfer on local heat transfer characteristic of porous media with internal heat source was described with a power-law-equation. The deviations between calculation and experimental values are within ±10%. (authors)

Correct integration of compressors and expanders in above ambient heat exchanger networks

International Nuclear Information System (INIS)

Fu, Chao; Gundersen, Truls

2016-01-01

The Appropriate Placement concept (also referred to as Correct Integration) is fundamental in Pinch Analysis. The placement of reactors, distillation columns, evaporators, heat pumps and heat engines in heat exchanger networks is well established. The placement of pressure changing equipment such as compressors and expanders is complex and less discussed in literature. A major difficulty is that both heat and work (not only heat) are involved. The integration of compressors and expanders separately into heat exchanger networks was recently investigated. A set of theorems were proposed for assisting the design. The problem is even more complex when both compressors and expanders are to be integrated. An important concern is about the sequence of integration with compressors and expanders, i.e. should compressors or expanders be implemented first. This problem is studied and a new theorem is formulated related to the Correct Integration of both compressors and expanders in above ambient heat exchanger networks. The objective is to minimize exergy consumption for the integrated processes. A graphical design methodology is developed for the integration of compressors and expanders into heat exchanger networks above ambient temperature. - Highlights: • The correct integration of compressors and expanders in heat exchanger networks is studied. • A theorem is proposed for heat integration between compressors and expanders. • The total exergy consumption is minimized.

Building integration of concentrating solar systems for heating applications

International Nuclear Information System (INIS)

Tsoutsou, Sapfo; Infante Ferreira, Carlos; Krieg, Jan; Ezzahiri, Mohamed

2014-01-01

A new solar collection system integrated on the façade of a building is investigated for Dutch climate conditions. The solar collection system includes a solar façade, a receiver tube and 10 Fresnel lenses. The Fresnel lenses Fresnel lenses considered were linear, non-imaging, line – focused with a system tracking the position of the sun that ensures vertical incidence of the direct solar radiation on the lenses. For the heating system a double-effect absorption heat pump, which requires high temperature of the heating fluid, was used, working with water and lithium-bromide as refrigerant and solution respectively. The Fresnel lens system is connected with the absorption heat pump through a thermal energy storage tank which accumulates the heat from the Fresnel lens system to provide it to the high pressure generator of the absorption heat pump. - Highlights: • The integration of Fresnel lenses in solar thermal building façades is investigated. • Using building integrated Fresnel lenses, 43% heating energy can be saved. • Energy savings in Mediterranean countries are significantly larger. • The absorption heat pump could make great contribution to energy savings for Dutch climate conditions

A new divided-wall heat integrated distillation column (HIDiC) for batch processing: Feasibility and analysis

International Nuclear Information System (INIS)

Jana, Amiya K.

2016-01-01

Highlights: • A novel heat integrated configuration is proposed for batch distillation. • The shell is divided into two closed semi-cylinders by a metal wall. • An open-loop variable manipulation policy is formulated. • The column improves its energy efficiency and economic performance. - Abstract: This work introduces a new heat integrated distillation column (HIDiC) for batch processing. Under this scheme, the entire cylindrical shell is proposed to divide vertically by a metal wall into two closed semi-cylinders. Aiming to generate an internal heat source, a heat pump system is employed over the left hand division to elevate the pressure of the right hand part with the application of HIDiC concept. This new divided-wall HIDiC column utilizes its own energy source by transferring heat from the high pressure (HP) to low pressure (LP) side, thereby reducing the utility consumption in both the still and condenser. To make this thermal integration technology more effective, a typical tray configuration is proposed in both sides of the divided-wall. Unlike the continuous flow distillation, the batch column shows unsteady state process characteristics that make its operation more challenging. With this, an open-loop variable manipulation policy is formulated so that the dynamics of the heat integrated column remain close, if not same, with its conventional counterpart. This is a necessary condition required for a fair comparison between them. Finally, the proposed configuration is illustrated by a binary column, showing an improvement in energy savings, entropy generation and cost over its conventional analogous. This thermally integrated configuration is relatively simple than the traditional HIDiC in terms of design and operation.

Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

KAUST Repository

Nehe, Prashant

2015-05-01

Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

Conjugated heat transfer of natural convection in pool with internal heat sources and convection in the tube

International Nuclear Information System (INIS)

Li Longjian; Liu Hongtao; Cui Wenzhi

2007-01-01

The conjugated heat transfer of natural convection in pool with internal heat source and the forced convection in the tube was analyzed, and the corresponding three-dimensional physical and mathematical model was proposed. A control volume based finite element method was employed to solve numerically the problem. The computations were performed for different internal heat source intensity of the pool and the different flow velocity in the tube. The computed heat transfer coefficients on the inner and outer wall showed well consistency of those calculated with the empirical correlations. Compared with the measured total heat transfer coefficients between the fluids in and out of the tube, the computed ones showed also the well consistency, which implied that the numerical model proposed in this paper was reliable. The research results revealed that the total heat transfer coefficients between the fluids were strongly affected by the internal heat source intensity of the pool liquid and the flow velocity in the tube. (authors)

Heat-balance integral method for heat transfer in superfluid helium

Directory of Open Access Journals (Sweden)

Baudouy Bertrand

2009-01-01

Full Text Available The heat-balance integral method is used to solve the non-linear heat diffusion equation in static turbulent superfluid helium (He II. Although this is an approximate method, it has proven that it gives solutions with fairly good accuracy in non-linear fluid dynamics and heat transfer. Using this method, it has been possible to develop predictive solutions that reproduce analytical solution and experimental data. We present the solutions of the clamped heat flux case and the clamped temperature case in a semi-infinite using independent variable transformation to take account of temperature dependency of the thermophysical properties. Good accuracy is obtained using the Kirchhoff transform whereas the method fails with the Goodman transform for larger temperature range.

Nonlinear throughflow and internal heating effects on vibrating porous medium

Directory of Open Access Journals (Sweden)

Palle Kiran

2016-06-01

Full Text Available The effect of vertical throughflow and internal heating effects on fluid saturated porous medium under gravity modulation is investigated. The amplitude of modulation is considered to be very small and the disturbances are expanded in terms of power series of amplitude of convection. A weakly nonlinear stability analysis is proposed to study stationary convection. The Nusselt number is obtained numerically to present the results of heat transfer while using Ginzburg–Landau equation. The vertical throughflow has dual effect either to destabilize or to stabilize the system for downward or upward directions. The effect of internal heat source (Ri>0 enhances or sink (Ri<0 diminishes heat transfer in the system. The amplitude and frequency of modulation have the effects of increasing or diminishing heat transport. For linear model Venezian approach suggested that throughflow and internal heating have both destabilizing and stabilizing effects for suitable ranges of Ω. Further, the study establishes that heat transport can be controlled effectively by a mechanism that is external to the system throughflow and gravity modulation.

An optimisation framework for thermal energy storage integration in a residential heat pump heating system

International Nuclear Information System (INIS)

Renaldi, R.; Kiprakis, A.; Friedrich, D.

2017-01-01

Highlights: • An integrated framework for the optimal design of low carbon heating systems. • Development of a synthetic heat demand model with occupancy profiles. • Linear model of a heat pump with thermal energy storage heating system. • Evaluation of domestic heating system from generally available input parameters. • The lower carbon heating system can be cost competitive with conventional systems. - Abstract: Domestic heating has a large share in the UK total energy consumption and significant contribution to the greenhouse gas emissions since it is mainly fulfilled by fossil fuels. Therefore, decarbonising the heating system is essential and an option to achieve this is by heating system electrification through heat pumps (HP) installation in combination with renewable power generation. A potential increase in performance and flexibility can be achieved by pairing HP with thermal energy storage (TES), which allows the shifting of heat demand to off peak periods or periods with surplus renewable electricity. We present a design and operational optimisation model which is able to assess the performance of HP–TES relative to conventional heating systems. The optimisation is performed on a synthetic heat demand model which requires only the annual heat demand, temperature and occupancy profiles. The results show that the equipment and operational cost of a HP system without TES are significantly higher than for a conventional system. However, the integration of TES and time-of-use tariffs reduce the operational cost of the HP systems and in combination with the Renewable Heating Incentive make the HP systems cost competitive with conventional systems. The presented demand model and optimisation procedure will enable the design of low carbon district heating systems which integrate the heating system with the variable renewable electricity supply.

Production of molten UO2 pools by internal heating: apparatus and preliminary experimental heat transfer results

International Nuclear Information System (INIS)

Chasanov, M.G.; Gunther, W.H.; Baker, L. Jr.

1977-01-01

The capability for removal of heat from a pool of molten fuel under postaccident conditions is an important consideration in liquid-metal fast breeder reactor safety analysis. No experimental data for pool heat transfer from molten UO 2 under conditions simulating internal heat generation by fission product decay have been reported previously in the literature. An apparatus to provide such data was developed and used to investigate heat transfer from pools containing up to 7.5 kg of UO 2 ; the internal heat generation rates and pool depths attained cover most of the ranges of interest for postaccident heat removal analysis. It was also observed in these studies that the presence of simulated fission products corresponding to approximately 150,000 kW-day/kg burnup had no significant effect on the observed heat transfer

Integrated Temperature Sensors based on Heat Diffusion

NARCIS (Netherlands)

Van Vroonhoven, C.P.L.

2015-01-01

This thesis describes the theory, design and implementation of a new class of integrated temperature sensors, based on heat diffusion. In such sensors, temperature is sensed by measuring the time it takes for heat to diffuse through silicon. An on-chip thermal delay can be determined by geometry and

Measuring weld heat to evaluate weld integrity

Energy Technology Data Exchange (ETDEWEB)

Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

2015-11-15

Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

Simulation of temperature in office with building integrated heating and cooling system

DEFF Research Database (Denmark)

Weitzmann, Peter

2002-01-01

In this paper a numerical investigation of the thermal indoor environment has been performed for an office with building integrated hydronic heating and cooling system. Today office buildings are designed in such a way, and have such high internal heat loads and solar gains, that some kind...... of cooling is normally necessary for most of the year. Even in as cool climates as in the Nordic countries. The way the cooling is often achieved is through air conditioning. This can in many cases lead to sick building syndrome (SBS) symptoms, and furthermore it results in high energy consumption periods...... the temperature of the concrete to a level slightly below the desired room temperature, the concrete will work as an absorber for the excess heat in the office. This can significantly reduce the need for air conditioning, which will give both improved indoor climate and lower energy costs in the building...

Heat and work integration: Fundamental insights and applications to carbon dioxide capture processes

International Nuclear Information System (INIS)

Fu, Chao; Gundersen, Truls

2016-01-01

Highlights: • The problem definition of heat and work integration is introduced. • The fundamental insights of heat and work integration are presented. • The design methodology is illustrated with two small test examples. • Applications of to three carbon dioxide capture processes are presented. - Abstract: The integration of heat has achieved a notable success in the past decades. Pinch Analysis is a well-established methodology for heat integration. Work is an equally important thermodynamic parameter. The enthalpy of a process stream can be changed by the transfer of heat and/or work. Heat and work are actually interchangeable and can thus be integrated. For example, compression processes consume more work at higher temperatures, however, the compression heat may be upgraded and utilized; expansion processes produce more work at higher temperatures, however, more heat may be required. The classical heat integration problem is thus extended to a new research topic about the integration of both heat and work. The aim of this paper is to present the problem definition, fundamental thermodynamic insights and industrial applications of heat and work integration. The results from studies on the three carbon dioxide capture processes show that significant energy savings can be achieved by proper heat and work integration. In the oxy-combustion process, the work consumption for cryogenic air separation is reduced by 10.1%. In the post-combustion membrane separation process, the specific work consumption for carbon dioxide separation is reduced by 12.9%. In the membrane air separation process, the net work consumption (excluding heat consumption) is reduced by 90%.

A totally heat-integrated distillation column (THIDiC) - the effect of feed pre-heating by distillate

Energy Technology Data Exchange (ETDEWEB)

Huang Kejin [School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: huangkj@mail.buct.edu.cn; Shan Lan; Zhu Qunxiong [School of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029 (China); Qian Jixin [School of Information Science and Technology, Zhejiang University, Zhejiang 300027 (China)

2008-06-15

An ideal heat-integrated distillation column (ideal HIDiC) is characterized by external zero-reflux and zero-reboil ratio operation. Since the distillate is a high-pressure vapor phase flow, it can be used to pre-heat the feed to be separated, thereby giving rise to a totally heat-integrated distillation column (THIDiC). Although the THIDiC is more thermodynamically efficient than the ideal HIDiC, it is found that the heat integration between the distillate and feed turns it into an open-loop integrating process and poses additional difficulties to process operation. Therefore, a careful decision must be made on the selection between the ideal HIDiC and the THIDiC during process development. In this paper, separation of a binary equimolar mixture of benzene and toluene is selected as an illustrative example. Both process design and operability analysis are conducted, with special emphasis focused on the characteristics of feed pre-heating with distillate. The results obtained show deep insight into the design and operation of the THIDiC.

A totally heat-integrated distillation column (THIDiC) - the effect of feed pre-heating by distillate

International Nuclear Information System (INIS)

Huang Kejin; Shan Lan; Zhu Qunxiong; Qian Jixin

2008-01-01

An ideal heat-integrated distillation column (ideal HIDiC) is characterized by external zero-reflux and zero-reboil ratio operation. Since the distillate is a high-pressure vapor phase flow, it can be used to pre-heat the feed to be separated, thereby giving rise to a totally heat-integrated distillation column (THIDiC). Although the THIDiC is more thermodynamically efficient than the ideal HIDiC, it is found that the heat integration between the distillate and feed turns it into an open-loop integrating process and poses additional difficulties to process operation. Therefore, a careful decision must be made on the selection between the ideal HIDiC and the THIDiC during process development. In this paper, separation of a binary equimolar mixture of benzene and toluene is selected as an illustrative example. Both process design and operability analysis are conducted, with special emphasis focused on the characteristics of feed pre-heating with distillate. The results obtained show deep insight into the design and operation of the THIDiC

Control assessment for heat integrated systems. An industrial case study for ethanol recovery

DEFF Research Database (Denmark)

Mauricio Iglesias, Miguel; Huusom, Jakob Kjøbsted; Sin, Gürkan

2013-01-01

Heat integration is essential for reducing the energy consumption of process industries. However, it may render the dynamic operation more interactive and difficult to control. This paper assesses the implications of heat integration in controllability and performance in energy reduction....... The assessment, both on open loop and closed loop, was carried out based on an industrial case study and compared to a modified case without heat integration. Although the heat integrated system displayed a certain deterioration of controllability, the control system made possible an efficient operation....... The reduction of energy consumption achieved thanks to heat integration was considerably larger than the losses due to poor control of the process, confirming the importance of heat integration in energy intensive processes....

Integration of biomass fast pyrolysis and precedent feedstock steam drying with a municipal combined heat and power plant

International Nuclear Information System (INIS)

Kohl, Thomas; Laukkanen, Timo P.; Järvinen, Mika P.

2014-01-01

Biomass fast pyrolysis (BFP) is a promising pre-treatment technology for converting biomass to transport fuel and in the future also for high-grade chemicals. BFP can be integrated with a municipal combined heat and power (CHP) plant. This paper shows the influence of BFP integration on a CHP plant's main parameters and its effect on the energetic and environmental performance of the connected district heating network. The work comprises full- and part-load operation of a CHP plant integrated with BFP and steam drying. It also evaluates different usage alternatives for the BFP products (char and oil). The results show that the integration is possible and strongly beneficial regarding energetic and environmental performance. Offering the possibility to provide lower district heating loads, the operation hours of the plant can be increased by up to 57%. The BFP products should be sold rather than applied for internal use as this increases the district heating network's primary energy efficiency the most. With this integration strategy future CHP plants can provide valuable products at high efficiency and also can help to mitigate global CO 2 emissions. - Highlights: • Part load simulation of a cogeneration plant integrated with biomas fast pyrolysis. • Analysis of energetic and environmental performance. • Assessment of different uses of the pyrolysis products

Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

International Nuclear Information System (INIS)

Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

2016-01-01

Highlights: • An integrated thermal management system is proposed for electric vehicle. • The parallel branch of battery chiller can supply additional cooling capacity. • Heat pipe performance on preheating mode is better than that on cooling mode. • Heat pipe heat exchanger is a feasible choice for battery thermal management. - Abstract: An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode.

Experimental study on single-phase convection heat transfer characteristics of pebble bed channels with internal heat generation

International Nuclear Information System (INIS)

Meng Xianke; Sun Zhongning; Zhou Ping; Xu Guangzhan

2012-01-01

The water-cooled pebble bed reactor core is the porous channels stacked with spherical fuel elements, having evident effect on enhancing heat transfer. Owing to the variability and randomness characteristics of it's interstice, pebble bed channels have a very complex heat transfer situation and have little correlative research. In order to research the heat transfer characters of pebble bed channels with internal heat source, electromagnetic induction heating method was adopted for overall heating the pebble bed which was composed of 8 mm diameter steel balls, and the internal heat transfer characteristics were researched. By comparing and analyzing the experimental data, the rule of power distribution and heat transfer coefficient with heat flux density, inlet temperature and working fluid's Re were got. According to the experimental data fitting, the dimensionless average heat transfer coefficient correlation criteria was got. The fitting results are good agreement with the experimental results within 12% difference. (authors)

Application of heat-balance integral method to conjugate thermal explosion

Directory of Open Access Journals (Sweden)

Novozhilov Vasily

2009-01-01

Full Text Available Conjugate thermal explosion is an extension of the classical theory, proposed and studied recently by the author. The paper reports application of heat-balance integral method for developing phase portraits for systems undergoing conjugate thermal explosion. The heat-balance integral method is used as an averaging method reducing partical differential equation problem to the set of first-order ordinary differential equations. The latter reduced problem allows natural interpretation in appropriately chosen phase space. It is shown that, with the help of heat-balance integral technique, conjugate thermal explosion problem can be described with a good accuracy by the set of non-linear first-order differential equations involving complex error function. Phase trajectories are presented for typical regimes emerging in conjugate thermal explosion. Use of heat-balance integral as a spatial averaging method allows efficient description of system evolution to be developed.

Single-phase convection heat transfer characteristics of pebble-bed channels with internal heat generation

International Nuclear Information System (INIS)

Meng Xianke; Sun Zhongning; Xu Guangzhan

2012-01-01

Graphical abstract: The core of the water-cooled pebble bed reactor is the porous channels which stacked with spherical fuel elements. The gaps between the adjacent fuel elements are complex because they are stochastic and often shift. We adopt electromagnetic induction heating method to overall heat the pebble bed. By comparing and analyzing the experimental data, we get the rule of power distribution and the rule of heat transfer coefficient with particle diameter, heat flux density, inlet temperature and working fluid's Re number. Highlights: ► We adopt electromagnetic induction heating method to overall heat the pebble bed to be the internal heat source. ► The ball diameter is smaller, the effect of the heat transfer is better. ► With Re number increasing, heat transfer coefficient is also increasing and eventually tends to stabilize. ► The changing of heat power makes little effect on the heat transfer coefficient of pebble bed channels. - Abstract: The reactor core of a water-cooled pebble bed reactor includes porous channels that are formed by spherical fuel elements. This structure has notably improved heat transfer. Due to the variability and randomness of the interstices in pebble bed channels, heat transfer is complex, and there are few studies regarding this topic. To study the heat transfer characters of pebble bed channels with internal heat sources, oxidized stainless steel spheres with diameters of 3 and 8 mm and carbon steel spheres with 8 mm diameters are used in a stacked pebble bed. Distilled water is used as a refrigerant for the experiments, and the electromagnetic induction heating method is used to heat the pebble bed. By comparing and analyzing the experimental results, we obtain the governing rules for the power distribution and the heat transfer coefficient with respect to particle diameter, heat flux density, inlet temperature and working fluid Re number. From fitting of the experimental data, we obtain the dimensionless average

Heat transfer measurements of internally heated liquids in cylindrical convection cells

International Nuclear Information System (INIS)

Fieg, G.

1978-10-01

In hypothetical reactor accidents, the thermohydraulic behaviour of core melts heated by the after-heat must be analyzed. For this purpose model experiments have been performed to study the stationary, natural convective heat transfer of internally heated fluids in cylindrical convertion cells investigating also the influence of geometry (aspect ratio) as well as of difference thermal wall conditions on to the heat transport characteristics. Axial temperature profiles, local heat flux densities at the vertical walls and their dependence, on the external Rayleigh number ar in detail reported, besides the Nusselt vs Rayleigh correlations for the aspect ratios HID=1 and 0,25. The results of these experiments are compared, as for ar possible, with existing thermohydraulic codes and simpler model asoumptions like the zone-model of Baker et. al. and after experimental verification, be used to study realistic PAHR situations. Velocity measurements by means of Laser-Doppler-Method yield information about the flow characteristics near the vertical walls and within the central part of the convecting fluid. (GL) [de

Transition to chaos in a square enclosure containing internal heat sources

Energy Technology Data Exchange (ETDEWEB)

Baytas, A.C. [Institute For Nuclear Energy, Istanbul (Turkey)

1995-09-01

A numerical investigation is performed to study the transition from steady to chaotic flow of a fluid confined in a two-dimensional square cavity. The cavity has rigid walls of constant temperature containing uniformly distributed internal heat source. Effects of the Rayleigh number of flow and heat transfer rates are studied. In addition to, same problem is solved for sinusoidally changing internal heat source to show its effect on the flow model and heat transfer of the enclosures. Details of oscillatory solutions and flow bifurcations are presented.

77 FR 33486 - Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and Products...

Science.gov (United States)

2012-06-06

...Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and Products Containing Same, DN 2899; the Commission is soliciting comments on any public interest issues raised by the complaint or complainant's filing under section 210.8(b) of the Commission's Rules of Practice and Procedure (19 CFR 210.8(b)).

Modeling, simulation, parametric study and economic assessment of reciprocating internal combustion engine integrated with multi-effect desalination unit

International Nuclear Information System (INIS)

Salimi, Mohsen; Amidpour, Majid

2017-01-01

Highlights: • Integration of small MED unit with gas engine power cycle is studied in this paper. • Modeling, simulation, parametric study and sensitivity analysis were performed. • A thermodynamic model for heat recovery and power generation of the gas engine has been presented. • Annualized Cost of System (ACS) has been employed for economic assessment. • Economic feasibilty dependence of integrated system on natural gas and water prices has been investigated. - Abstract: Due to thermal nature of multi-effect desalination (MED), its integration with a suitable power cycle is highly desirable for waste heat recovery. One of the proper power cycle for proposed integration is internal combustion engine (ICE). The exhaust gas heat of ICE is used to produce motive steam for the required heat for the first effect of MED system. Also, the water jacket heat is utilized in a heat exchanger to pre-heat the seawater. This paper studies a thermodynamic model for a tri-generation system composed of ICE integrated with MED. The ICE thermodynamic model has been used in place of different empirical efficiency relations to estimate performance – load curves reasonably. The entire system performance has been coded in MATLAB, and the results of proposed thermodynamic model for the engine have been verified by manufacturer catalogue. By increasing the engine load from 40% to 100%, the water production of MED unit will increase from 4.38 cubic meters per day to 26.78 cubic meters per day and the tri-generation efficiency from 31% to 56%. Economic analyses of the MED unit integrated with ICE was performed based on Annualized Cost of System method. This integration makes the system more economical. It has been determined that in higher market prices for fresh water (more than 7 US$ per cubic meter), the increase in effects number is more significant to the period of return decrement.

Flexible heat pipes with integrated bioinspired design

Directory of Open Access Journals (Sweden)

Chao Yang

2015-02-01

Full Text Available In this work we report the facile fabrication and performance evaluation of flexible heat pipes that have integrated bioinspired wick structures and flexible polyurethane polymer connector design between the copper condenser and evaporator. Inside the heat pipe, a bioinspired superhydrophilic strong-base-oxidized copper mesh with multi-scale micro/nano-structures was used as the wicking material and deionized water was selected as working fluid. Thermal resistances of the fabricated flexible heat pipes charged with different filling ratios were measured under thermal power inputs ranging from 2 W to 12 W while the device was bent at different angles. The fabricated heat pipes with a 30% filling ratio demonstrated a low thermal resistance less than 0.01 K/W. Compared with the vertically oriented straight heat pipes, bending from 30° up to 120° has negligible influence on the heat-transfer performance. Furthermore, repeated heating tests indicated that the fabricated flexible heat pipes have consistent and reliable heat-transfer performance, thus would have important applications for advanced thermal management in three dimensional and flexible electronic devices.

Development of an Air-Source Heat Pump Integrated with a Water Heating / Dehumidification Module

Energy Technology Data Exchange (ETDEWEB)

Rice, C Keith [ORNL; Uselton, Robert B. [Lennox Industries, Inc; Shen, Bo [ORNL; Baxter, Van D [ORNL; Shrestha, Som S [ORNL

2014-01-01

A residential-sized dual air-source integrated heat pump (AS-IHP) concept is under development in partnership between ORNL and a manufacturer. The concept design consists of a two-stage air-source heat pump (ASHP) coupled on the air distribution side with a separate novel water heating/dehumidification (WH/DH) module. The motivation for this unusual equipment combination is the forecast trend for home sensible loads to be reduced more than latent loads. Integration of water heating with a space dehumidification cycle addresses humidity control while performing double-duty. This approach can be applied to retrofit/upgrade applications as well as new construction. A WH/DH module capable of ~1.47 L/h water removal and ~2 kW water heating capacity was assembled by the manufacturer. A heat pump system model was used to guide the controls design; lab testing was conducted and used to calibrate the models. Performance maps were generated and used in a TRNSYS sub-hourly simulation to predict annual performance in a well-insulated house. Annual HVAC/WH energy savings of ~35% are predicted in cold and hot-humid U.S. climates compared to a minimum efficiency baseline.

An Integrated Control System for Heating and Indoor Climate Applications

DEFF Research Database (Denmark)

Tahersima, Fatemeh

2012-01-01

which geothermal heat pump, solar driven heat pumps and the other types are categorized as renewable or renewable energy sources. In the present study, we investigated modeling and control of hydronic heat emitters integrated with a ground-source heat pump. Optimization of the system performance...... in terms of energy efficiency, associated energy cost and occupants’ thermal comfort is the main objective to be fulfilled via design of an integrated controller. We also proposed control strategies to manage energy consumption of the building to turn domestic heat demands into a flexible load in the smart...... in order to maximize the heat pump’s efficiency and by this means reduce the power consumption of the heat pump. The hypothesis is that such an optimal point coincides with saturation of at least one of the subsystems control valves. The idea is implemented experimentally using simple PI and on...

Dynamic Complexity Study of Nuclear Reactor and Process Heat Application Integration

International Nuclear Information System (INIS)

Taylor, J'Tia Patrice; Shropshire, David E.

2009-01-01

This paper describes the key obstacles and challenges facing the integration of nuclear reactors with process heat applications as they relate to dynamic issues. The paper also presents capabilities of current modeling and analysis tools available to investigate these issues. A pragmatic approach to an analysis is developed with the ultimate objective of improving the viability of nuclear energy as a heat source for process industries. The extension of nuclear energy to process heat industries would improve energy security and aid in reduction of carbon emissions by reducing demands for foreign derived fossil fuels. The paper begins with an overview of nuclear reactors and process application for potential use in an integrated system. Reactors are evaluated against specific characteristics that determine their compatibility with process applications such as heat outlet temperature. The reactor system categories include light water, heavy water, small to medium, near term high-temperature, and far term high temperature reactors. Low temperature process systems include desalination, district heating, and tar sands and shale oil recovery. High temperature processes that support hydrogen production include steam reforming, steam cracking, hydrogen production by electrolysis, and far-term applications such as the sulfur iodine chemical process and high-temperature electrolysis. A simple static matching between complementary systems is performed; however, to gain a true appreciation for system integration complexity, time dependent dynamic analysis is required. The paper identifies critical issues arising from dynamic complexity associated with integration of systems. Operational issues include scheduling conflicts and resource allocation for heat and electricity. Additionally, economic and safety considerations that could impact the successful integration of these systems are considered. Economic issues include the cost differential arising due to an integrated system

Wind power integration using individual heat pumps – Analysis of different heat storage options

DEFF Research Database (Denmark)

Hedegaard, Karsten; Mathiesen, Brian Vad; Lund, Henrik

2012-01-01

Significant installations of individual heat pumps are expected in future energy systems due to their economic competitiveness. This case study of the Danish energy system in 2020 with 50% wind power shows that individual heat pumps and heat storages can contribute to the integration of wind power....... Heat accumulation tanks and passive heat storage in the construction are investigated as two alternative storage options in terms of their ability to increase wind power utilisation and to provide cost-effective fuel savings. Results show that passive heat storage can enable equivalent to larger...... reductions in excess electricity production and fuel consumption than heat accumulation tanks. Moreover, passive heat storage is found to be significantly more cost-effective than heat accumulation tanks. In terms of reducing fuel consumption of the energy system, the installation of heat pumps is the most...

Thermoelectricity from wasted heat of integrated circuits

KAUST Repository

Fahad, Hossain M.

2012-05-22

We demonstrate that waste heat from integrated circuits especially computer microprocessors can be recycled as valuable electricity to power up a portion of the circuitry or other important accessories such as on-chip cooling modules, etc. This gives a positive spin to a negative effect of ever increasing heat dissipation associated with increased power consumption aligned with shrinking down trend of transistor dimension. This concept can also be used as an important vehicle for self-powered systemson- chip. We provide theoretical analysis supported by simulation data followed by experimental verification of on-chip thermoelectricity generation from dissipated (otherwise wasted) heat of a microprocessor.

Air source integrated heat pump simulation model for EnergyPlus

Energy Technology Data Exchange (ETDEWEB)

Shen, Bo; New, Joshua; Baxter, Van

2017-12-01

An Air Source Integrated Heat Pump (AS-IHP) is an air source, multi-functional spacing conditioning unit with water heating function (WH), which can lead to great energy savings by recovering the condensing waste heat for domestic water heating. This paper summarizes development of the EnergyPlus AS-IHP model, introducing the physics, sub-models, working modes, and control logic. Based on the model, building energy simulations were conducted to demonstrate greater than 50% annual energy savings, in comparison to a baseline heat pump with electric water heater, over 10 US cities, using the EnergyPlus quick-service restaurant template building. We assessed water heating energy saving potentials using AS-IHP versus both gas and electric baseline systems, and pointed out climate zones where AS-IHPs are promising. In addition, a grid integration strategy was investigated to reveal further energy saving and electricity cost reduction potentials, via increasing the water heating set point temperature during off-peak hours and using larger water tanks.

Integration of large-scale heat pumps in the district heating systems of Greater Copenhagen

DEFF Research Database (Denmark)

Bach, Bjarne; Werling, Jesper; Ommen, Torben Schmidt

2016-01-01

This study analyses the technical and private economic aspects of integrating a large capacity of electric driven HP (heat pumps) in the Greater Copenhagen DH (district heating) system, which is an example of a state-of-the-art large district heating system with many consumers and suppliers....... The analysis was based on using the energy model Balmorel to determine the optimum dispatch of HPs in the system. The potential heat sources in Copenhagen for use in HPs were determined based on data related to temperatures, flows, and hydrography at different locations, while respecting technical constraints...

Wind power integration with heat pumps, heat storages, and electric vehicles – Energy systems analysis and modelling

DEFF Research Database (Denmark)

Hedegaard, Karsten

The fluctuating and only partly predictable nature of wind challenges an effective integration of large wind power penetrations. This PhD thesis investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing...... in an energy system context. Energy systems analyses reveal that the heat pumps can even without flexible operation contribute significantly to facilitating larger wind power investments and reducing system costs, fuel consumption, and CO2 emissions. When equipping the heat pumps with heat storages, only...... moderate additional benefits are achieved. Hereof, the main benefit is that the need for investing in peak/reserve capacities can be reduced through peak load shaving. It is more important to ensure flexible operation of electric vehicles than of individual heat pumps, due to differences in the load...

The Logic and Issues of International Regional Tax Integration

OpenAIRE

Kudryashova, Ekaterina

2016-01-01

The article is devoted to the issues of international regional tax integration. The international economic integration has two mainstreams: global and regional economic integration. The global tax integration is concerned only with double taxation matters while the regional tax integration aims at procuring of four fundamental freedoms of common market and goes far beyond the elimination of double taxation. The legal solution for both global and regional international tax integration can not ...

Dynamic Complexity Study of Nuclear Reactor and Process Heat Application Integration

Energy Technology Data Exchange (ETDEWEB)

J' Tia Patrice Taylor; David E. Shropshire

2009-09-01

Abstract This paper describes the key obstacles and challenges facing the integration of nuclear reactors with process heat applications as they relate to dynamic issues. The paper also presents capabilities of current modeling and analysis tools available to investigate these issues. A pragmatic approach to an analysis is developed with the ultimate objective of improving the viability of nuclear energy as a heat source for process industries. The extension of nuclear energy to process heat industries would improve energy security and aid in reduction of carbon emissions by reducing demands for foreign derived fossil fuels. The paper begins with an overview of nuclear reactors and process application for potential use in an integrated system. Reactors are evaluated against specific characteristics that determine their compatibility with process applications such as heat outlet temperature. The reactor system categories include light water, heavy water, small to medium, near term high-temperature, and far term high temperature reactors. Low temperature process systems include desalination, district heating, and tar sands and shale oil recovery. High temperature processes that support hydrogen production include steam reforming, steam cracking, hydrogen production by electrolysis, and far-term applications such as the sulfur iodine chemical process and high-temperature electrolysis. A simple static matching between complementary systems is performed; however, to gain a true appreciation for system integration complexity, time dependent dynamic analysis is required. The paper identifies critical issues arising from dynamic complexity associated with integration of systems. Operational issues include scheduling conflicts and resource allocation for heat and electricity. Additionally, economic and safety considerations that could impact the successful integration of these systems are considered. Economic issues include the cost differential arising due to an integrated

Adding rectifying/stripping section type heat integration to a pressure-swing distillation (PSD) process

International Nuclear Information System (INIS)

Huang Kejin; Shan Lan; Zhu Qunxiong; Qian Jixin

2008-01-01

This paper studies the economical effect of considering rectifying/stripping section type heat integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging heat integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type heat integration with the rectifying/stripping section type heat integration in process synthesis and design

Adding rectifying/stripping section type heat integration to a pressure-swing distillation (PSD) process

Energy Technology Data Exchange (ETDEWEB)

Huang Kejin [School of Information Science and Technology, Beijing University of Chemical Technology, Chaoyang-qu, Beijing-shi, Beijing 100029 (China)], E-mail: huangkj@mail.buct.edu.cn; Shan Lan; Zhu Qunxiong [School of Information Science and Technology, Beijing University of Chemical Technology, Chaoyang-qu, Beijing-shi, Beijing 100029 (China); Qian Jixin [School of Information Science and Technology, Zhejiang University, Xihu-qu, Hangzhou-shi, Zhejiang 300027 (China)

2008-06-15

This paper studies the economical effect of considering rectifying/stripping section type heat integration in a pressure-swing distillation (PSD) process separating a binary homogeneous pressure-sensitive azeotrope. The schemes for arranging heat integration between the rectifying section and the stripping section of the high- and low-pressure distillation columns, respectively, are derived and an effective procedure is devised for the conceptual process design of the heat-integrated PSD processes. In terms of the separation of a binary azeotropic mixture of acetonitrile and water, intensive comparisons are made between the conventional and heat-integrated PSD processes. It is demonstrated that breaking a pressure-sensitive azeotropic mixture can be made more economical than the current practice with the conventional PSD process. For boosting further the thermodynamic efficiency of a PSD process, it is strongly suggested to consider simultaneously the condenser/reboiler type heat integration with the rectifying/stripping section type heat integration in process synthesis and design.

An Innovative VHTR Waste Heat Integration with Forward Osmosis Desalination Process

Energy Technology Data Exchange (ETDEWEB)

Park, Min Young; Kim, Eung Soo [Seoul National Univ., Seoul (Korea, Republic of)

2013-10-15

The integration concept implies the coupling of the waste heat from VHTR with the draw solute recovery system of FO process. By integrating these two novel technologies, advantages, such as improvement of total energy utilization, and production of fresh water using waste heat, can be achieved. In order to thermodynamically analyze the integrated system, the FO process and power conversion system of VHTR are simulated using chemical process software UNISIM together with OLI property package. In this study, the thermodynamic analysis on the VHTR and FO integrated system has been carried out to assess the feasibility of the concept. The FO process including draw solute recovery system is calculated to have a higher GOR compared to the MSF and MED when reasonable FO performance can be promised. Furthermore, when FO process is integrated with the VHTR to produce potable water from waste heat, it still shows a comparable GOR to typical GOR values of MSF and MED. And the waste heat utilization is significantly higher in FO than in MED and MSF. This results in much higher water production when integrated to the same VHTR plant. Therefore, it can be concluded that the suggested integrated system of VHTR and FO is a very promising and strong system concept which has a number of advantages over conventional technologies.

Prediction of strongly-heated internal gas flows

International Nuclear Information System (INIS)

McEligot, D.M.; Shehata, A.M.; Kunugi, Tomoaki

1997-01-01

The purposes of the present article are to remind practitioners why the usual textbook approaches may not be appropriate for treating gas flows heated from the surface with large heat fluxes and to review the successes of some recent applications of turbulence models to this case. Simulations from various turbulence models have been assessed by comparison to the measurements of internal mean velocity and temperature distributions by Shehata for turbulent, laminarizing and intermediate flows with significant gas property variation. Of about fifteen models considered, five were judged to provide adequate predictions

Wind power integration with heat pumps, heat storages, and electric vehicles - Energy systems analysis and modelling

Energy Technology Data Exchange (ETDEWEB)

Hedegaard, K.

2013-09-15

This PhD investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing research, the main focus is put on individual heat pumps in the residential sector (one-family houses) and the possibilities for flexible operation, using the heat storage options available. Several energy systems analyses are performed using the energy system models, Balmorel, developed at the former TSO, ElkraftSystem, and, EnergyPLAN, developed at Aalborg University. The Danish energy system towards 2030, with wind power penetrations of up to 60 %, is used as a case study in most of the analyses. Both models have been developed further, resulting in an improved representation of individual heat pumps and heat storages. An extensive model add-on for Balmorel renders it possible to optimise investment and operation of individual heat pumps and different types of heat storages, in integration with the energy system. Total costs of the energy system are minimised in the optimisation. The add-on incorporates thermal building dynamics and covers various different heat storage options: intelligent heat storage in the building structure for houses with radiator heating and floor heating, respectively, heat accumulation tanks on the space heating circuit, as well as hot water tanks. In EnergyPLAN, some of the heat storage options have been modelled in a technical optimisation that minimises fuel consumption of the energy system and utilises as much wind power as possible. The energy systems analyses reveal that in terms of supporting wind power integration, the installation of individual heat pumps is an important step, while adding heat storages to the heat pumps is less influential. When equipping the heat pumps with heat storages, only moderate system benefits can be gained. Hereof, the main system benefit is that the need for peak/reserve capacity investments can be reduced through peak load shaving; in

Program Integration for International Technology Exchange

International Nuclear Information System (INIS)

Rea, J.L.

1993-01-01

Sandia National Laboratories (SNL), Albuquerque, New Mexico, supports the International Technology Exchange Division (ITED) through the integration of all international activities conducted within the DOE's Office of Environmental Management (EM)

Transportation fuel production from gasified biomass integrated with a pulp and paper mill – Part A: Heat integration and system performance

International Nuclear Information System (INIS)

Isaksson, Johan; Jansson, Mikael; Åsblad, Anders; Berntsson, Thore

2016-01-01

Production of transportation fuels from biorefineries via biomass gasification has been suggested as a way of introducing renewable alternatives in the transportation system with an aim to reduce greenhouse gas emissions to the atmosphere. By co-locating gasification-based processes within heat demanding industries, excess heat from the gasification process can replace fossil or renewable fuels. The objective of this study was to compare the heat integration potential of four different gasification-based biorefinery concepts with a chemical pulp and paper mill. The results showed that the choice of end-product which was either methanol, Fischer-Tropsch crude, synthetic natural gas or electricity, can have significant impact on the heat integration potential with a pulp and paper mill and that the heat saving measures implemented in the mill in connection to integration of a gasification process can increase the biomass resource efficiency by up to 3%-points. Heat saving measures can reduce the necessary biomass input to the biorefinery by 50% if the sizing constraint is to replace the bark boiler with excess heat from the biorefinery. A large integrated gasification process with excess steam utilisation in a condensing turbine was beneficial only if grid electricity is produced at below 30% electrical efficiency. - Highlights: • Biomass gasification integrated with a pulp and paper mill. • Different sizing constraints of integrated biofuel production. • The biofuel product largely influence the heat integration potential. • An oversized gasifier for increased power production could be favourable.

Building Space Heating with a Solar-Assisted Heat Pump Using Roof-Integrated Solar Collectors

Directory of Open Access Journals (Sweden)

Zhiyong Yang

2011-03-01

Full Text Available A solar assisted heat pump (SAHP system was designed by using a roof-integrated solar collector as the evaporator, and then it was demonstrated to provide space heating for a villa in Tianjin, China. A building energy simulation tool was used to predict the space heating load and a three dimensional theoretical model was established to analyze the heat collection performance of the solar roof collector. A floor radiant heating unit was used to decrease the energy demand. The measurement results during the winter test period show that the system can provide a comfortable living space in winter, when the room temperature averaged 18.9 °C. The average COP of the heat pump system is 2.97 and with a maximum around 4.16.

Multi-boiling Heat Transfer Analysis of a Convective Straight Fin with Temperature-Dependent Thermal Properties and Internal Heat Generation

Directory of Open Access Journals (Sweden)

Gbeminiyi Sobamowo

2017-10-01

Full Text Available In this study, by using the finite volume method, the heat transfer in a convective straight fin with temperature-dependent thermal properties and an internal heat generation under multi-boiling heat transfer modes are analyzed. In this regard, the local heat transfer coefficient is considered to vary within a power-law function of temperature. In the present study, the coexistence of all the boiling modes is taken into consideration. The developed heat transfer models and the corresponding numerical solutions are used to investigate the effects of various thermo-geometric parameters on the thermal performance of the longitudinal rectangular fin. The results shows that the fin temperature distribution, the total heat transfer, and the fin efficiency are significantly affected by the thermo-geometric parameters of the fin and the internal heat generation within the fin. The obtained results can provide a platform for improvements in the design of the fin in the heat transfer equipment.

Dry out of a fluidized particle bed with internal heat generation

International Nuclear Information System (INIS)

Keowen, R.S.; Catton, I.

1975-03-01

An apparatus was designed to adequately simulate the characteristics of a particle bed formed by nuclear reactor fuel after the reactor has been operable for some length of time at high power. This was accomplished by using a 10 KW, 453 Kc induction heater, coupled through a multi-turn work coil to particle beds of cast steel shot and lead shot in water. The temperature response and dryout condition was determined for various bed levels, particle diameters, and heat fluxes. Analysis of the data retrieved from the bed was used to generate a family of curves to predict the necessary conditions for dryout to occur within a fluidized particle bed with internal heat generation. The results presented here, with internal heat generation, show that previous results with bottom heating and volume heating are conservative. (U.S.)

Geometry, Heat Equation and Path Integrals on the Poincare Upper Half-Plane

OpenAIRE

Reijiro, KUBO; Research Institute for Theoretical Physics Hiroshima University

1988-01-01

Geometry, heat equation and Feynman's path integrals are studied on the Poincare upper half-plane. The fundamental solution to the heat equation ∂f/∂t=Δ_Hf is expressed in terms of a path integral defined on the upper half-plane. It is shown that Kac's statement that Feynman's path integral satisfies the Schrodinger equation is also valid for our case.

History of heat pumps - Swiss contributions and international milestones

Energy Technology Data Exchange (ETDEWEB)

Zogg, M

2008-05-15

Compared to conventional boilers, heating by heat pumps cuts down fuel consumption and CO{sub 2} emissions to about 50%. Compared to electric resistance heating, the energy consumption is even reduced up to 80%. Therefore, the impressive market penetration growth of heat pumps will continue. Swiss pioneers were the first to realize functioning vapour recompression plants. The first European heat pumps were realized in Switzerland. To date it remains one of the heat pump champions. Swiss pioneering work in the development of borehole heat exchangers, sewage heat recovery, oil free piston compressors and turbo compressors is well known. The biggest heat pump ever built comes from Switzerland. Although there is a fairly comprehensive natural gas distribution grid, 75% of the new single-family homes built in Switzerland are currently heated by heat pumps. This paper presents some of the highlights of this success story focusing on Swiss developments and relating them to the international milestones. In order to indicate the direction in which the future development might go to, some recent Swiss research projects are presented as well. (author)

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

International symposium on transient convective heat transfer: book of abstracts

International Nuclear Information System (INIS)

1996-01-01

The international symposium on convective heat transfer was held on 19-23 August 1996, in Cesme, Izmir, Turkey. The spesialists discussed forced convection, heat exchangers, free convection and multiphase media and phase change at the meeting. Almost 53 papers were presented in the meeting

A solar air collector with integrated latent heat thermal storage

Directory of Open Access Journals (Sweden)

Klimes Lubomir

2012-04-01

Full Text Available Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data.

The optimization of longitudinal convective fins with internal heat generation

International Nuclear Information System (INIS)

Razelos, P.

1979-01-01

The solution of the optimization problem for longitudinal convective fins of constant thickness, triangular or parabolic profile, and uniform internal heat generation, is presented. The cases considered are those of a given heat generation density, total heat generation and heat generation per unit width of the fin, when either the heat dissipation or the width of the fin is prescribed. The results are set forth in a nondimensional form, which are presented graphically. The effect of the fin's thermal conductivity upon the optimum dimensions is discussed, and limiting values for the heat generation and the heat dissipation, which may be imposed on the fin for a feasible optimization, are also obtained. (Auth.)

Convection heat transfer

CERN Document Server

Bejan, Adrian

2013-01-01

Written by an internationally recognized authority on heat transfer and thermodynamics, this second edition of Convection Heat Transfer contains new and updated problems and examples reflecting real-world research and applications, including heat exchanger design. Teaching not only structure but also technique, the book begins with the simplest problem solving method (scale analysis), and moves on to progressively more advanced and exact methods (integral method, self similarity, asymptotic behavior). A solutions manual is available for all problems and exercises.

Geometry, heat equation and path integrals on the Poincare upper half-plane

International Nuclear Information System (INIS)

Kubo, Reijiro.

1987-08-01

Geometry, heat equation and Feynman's path integrals are studied on the Poincare upper half-plane. The fundamental solution to the heat equation δf/δt = Δ H f is expressed in terms of a path integral defined on the upper half-plane. It is shown that Kac's proof that Feynman's path integral satisfies the Schroedinger equation is also valid for our case. (author)

From heat integration targets toward implementation – A TSA (total site analysis)-based design approach for heat recovery systems in industrial clusters

International Nuclear Information System (INIS)

Hackl, Roman; Harvey, Simon

2015-01-01

The European process industry is facing major challenges to decrease production costs. One strategy to achieve this is by increasing energy efficiency. Single chemical processes are often well-integrated and the tools to target and design such measures are well developed. Site-wide heat integration based on total site analysis tools can be used to identify opportunities to further increase energy efficiency. However, the methodology has to be developed further in order to enable identification of practical heat integration measures in a systematic way. Designing site-wide heat recovery systems across an industrial cluster is complex and involves aspects apart from thermal process and utility flows. This work presents a method for designing a roadmap of heat integration investments based on total site analysis. The method is applied to a chemical cluster in Sweden. The results of the case study show that application of the proposed method can achieve up to 42% of the previously targeted hot utility savings of 129 MW. A roadmap of heat integration systems is suggested, ranging from less complex systems that achieve a minor share of the heat recovery potential to sophisticated, strongly interdependent systems demanding large investments and a high level of collaboration. - Highlights: • Methodology focused on the practical implementation of site-wide heat recovery. • Algorithm to determine a roadmap of heat integration investments. • Case study: 42% hot utility savings potential at a pay-back period of 3.9y.

Organizational aspects of integrated reporting preparation according to international standard «Integrated reporting»

Directory of Open Access Journals (Sweden)

M.O. Maksymchuk

2016-12-01

Full Text Available Integrated Reporting is an innovative reporting for business entities, therefore the issue of the organization the preparation of this reporting is an actual. The absence of legislative regulation of integrated reporting at national level of legal documents has greatly affected the issue, because the only document, that specifies the requirements for integrated reporting is the international standard «integrated reporting». The article considers the organizational principles of integrated reporting preparation. Taking into account the requirements of the international standard «integrated reporting», the authors make the attempts to define the basic organizational stages of such reporting, that allows to introduce the integrated reporting in a structured way and logically. It is proposed on the enterprises preparing the integrated reporting to constitute the schedule of the formation of the integrated reporting. In addition, the important thing is to develop the internal policy for determining materiality by the use of the professional judgment. The appropriate internal policy is assigned to disclose the materiality process in an integrated reporting for decision-making on the inclusion or exclusion issues to be understandable for users.

Analysis of natural convection heat transfer and flows in internally heated stratified liquid pools

International Nuclear Information System (INIS)

Gubaidullin, A.A. Jr.; Dinh, T.N.; Sehgal, B.R.

1999-01-01

In this paper, natural convection flows and heat transfer in a liquid pool, with two superposed immiscible fluid layers, are analyzed. The objective of the study is to examine the effect of interfacial hydrodynamics and to develop a method which enables energy splitting to be evaluated in a stratified liquid pool. The thermal convection, with and without an internal heat source, in a rectangular cavity with different pairs of fluids was numerically simulated by a CFD code FLOW-3D. It was found that the code performs very well for prediction of heat transfer coefficients for different conditions. The hydrodynamic coupling between immiscible layers was found to have minor, if any, impact on the natural convection heat transfer for the conditions examined. Calculated results were used to develop, and validate, a new correlation for energy splitting and for heat transfer in stratified liquid pools

International Energy Agency Solar Heating and Cooling Program

Science.gov (United States)

Brooks, A. J.

This trip was undertaken to participate in and represent the United States Industry at the International Energy Agency (IEA) Solar Heating and Cooling Program (SHCP) Task 14 Workshop. The meeting took place at the A1 Bani Hotel in Rome Italy.

'Eco-house 99' - Full-scale demonstration of solar walls with building integrated heat storages

Energy Technology Data Exchange (ETDEWEB)

Hummelshoej, R.M.; Rahbek, J.E. [COWI Consulting Engineers and Planners AS (Denmark)

2000-07-01

A critical issue for solar systems in northern latitudes is the economic profitability. It is often said that the techniques for solar utilisation are expensive and unprofitable. This is, however, not always the case. A new project with 59 low energy terrace houses was carried out in Kolding, Denmark. The houses are designed as ecological buildings with emphasis on total economy based on low operation and maintenance costs, energy conservation and passive/hybrid solar utilisation. Besides direct solar gain through windows, each house has a solar wall of 6-8.5 m{sup 2} on the south facade. The solar walls are used both for heating of ventilation air and for space heating. The solar walls deliver heat to the dwellings during the heating season. To optimise the energy utilisation from the solar walls, the energy is stored internally in building integrated heat storages. Two different new types of prefabricated heat storages are built into the houses. One is an internal concrete wall with embedded ventilation pipes, and the other is a hollow concrete element with integrated stone bed. The heat storages are mainly designed to store solar energy from the day to the evening and the night. Because the solar walls and the heat storages have been a part of the design process from the start, the additional expenses are as low as 30-140 Euro/m{sup 2} solar wall compared with the alternative facade. This is far less than what it costs to add a solar wall on an existing building. Measurements over one year show that the yield of the solar walls is in the range of 115-125 kWh/m{sup 2}/year as expected. With the actual financing, the annual payment of the additional expenses for the solar systems is between 1-6 Euro/m{sup 2} solar wall, while the annual savings are about 5 Euro/year/m{sup 2} (with an energy price of 0.042 Euro/kWh). Dependent on which alternative facade construction the solar wall system is compared with, the profit of the system is in the range of 1 to +4 Euro

Integral methods of solving boundary-value problems of nonstationary heat conduction and their comparative analysis

Science.gov (United States)

Kot, V. A.

2017-11-01

The modern state of approximate integral methods used in applications, where the processes of heat conduction and heat and mass transfer are of first importance, is considered. Integral methods have found a wide utility in different fields of knowledge: problems of heat conduction with different heat-exchange conditions, simulation of thermal protection, Stefantype problems, microwave heating of a substance, problems on a boundary layer, simulation of a fluid flow in a channel, thermal explosion, laser and plasma treatment of materials, simulation of the formation and melting of ice, inverse heat problems, temperature and thermal definition of nanoparticles and nanoliquids, and others. Moreover, polynomial solutions are of interest because the determination of a temperature (concentration) field is an intermediate stage in the mathematical description of any other process. The following main methods were investigated on the basis of the error norms: the Tsoi and Postol’nik methods, the method of integral relations, the Gudman integral method of heat balance, the improved Volkov integral method, the matched integral method, the modified Hristov method, the Mayer integral method, the Kudinov method of additional boundary conditions, the Fedorov boundary method, the method of weighted temperature function, the integral method of boundary characteristics. It was established that the two last-mentioned methods are characterized by high convergence and frequently give solutions whose accuracy is not worse that the accuracy of numerical solutions.

Heat-pump-centered integrated community energy systems

Energy Technology Data Exchange (ETDEWEB)

Schaetzle, W.J.; Brett, C.E.; Seppanen, M.S.

1979-12-01

The heat-pump-centered integrated community energy system (HP-ICES) supplies district heating and cooling using heat pumps and a thermal energy storage system which is provided by nature in underground porous formations filled with water, i.e., aquifers. The energy is transported by a two-pipe system, one for warm water and one for cool water, between the aquifers and the controlled environments. Each energy module contains the controlled environments, an aquifer, wells for access to the aquifer, the two pipe water distribution system and water source heat pumps. The heat pumps upgrade the energy in the distribution system for use in the controlled environments. Economically, the system shows improvement on both energy usage and capital costs. The system saves over 60% of the energy required for resistance heating; saves over 30% of the energy required for most air-source heat pumps and saves over 60% of the energy required for gas, coal, or oil heating, when comparing to energy input required at the power plant for heat pump usage. The proposed system has been analyzed as demonstration projects for a downtown portion of Louisville, Kentucky, and a section of Fort Rucker, Alabama. The downtown Louisville demonstration project is tied directly to major buildings while the Fort Rucker demonstration project is tied to a dispersed subdivision of homes. The Louisville project shows a payback of approximately 3 y, while Fort Rucker is approximately 30 y. The primary difference is that at Fort Rucker new heat pumps are charged to the system. In Louisville, either new construction requiring heating and cooling systems or existing chillers are utilized. (LCL)

Rapid self-heating and internal temperature sensing of lithium-ion batteries at low temperatures

International Nuclear Information System (INIS)

Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Yang, Xiao-Guang; Tian, Hua; Wang, Chao-Yang

2016-01-01

Highlights: • Self-heating lithium-ion battery (SHLB) structure provided a practical solution to the poor performance at subzero temperatures. • We report an improved SHLB that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than previously reported. • The nickel foil heating element embedded inside a SHLB cell plays a dominant role in rapid self-heating. • The embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS). • 2-sheet design self-heats faster than 1-sheet design due to more uniform internal temperature distribution. - Abstract: The recently discovered self-heating lithium-ion battery structure provided a practical solution to the poor performance at subzero temperatures that has hampered battery technology for decades. Here we report an improved self-heating lithium-ion battery (SHLB) that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than that reported previously. We reveal that a nickel foil heating element embedded inside a SHLB cell plays a dominant role in self-heating and we experimentally demonstrate that a 2-sheet design can achieve dramatically accelerated self-heating due to more uniform internal temperature distribution. We also report, for the first time, that this embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS) due to the perfectly linear relationship between the foil’s electrical resistance and temperature.

Integral representation of nonlinear heat transport

International Nuclear Information System (INIS)

Kishimoto, Y.; Mima, K.; Haines, M.G.

1985-07-01

The electron distribution function in a plasma with steep temperature gradient is obtained from a Fokker-Planck equation by Green's function method. The formula describes the nonlocal effects on thermal transport over the range, λ e /L e /L → 0. As an example, the heat wave is analyzed numerically by the integral formula and it is found that the previous simulation results are well reproduced. (author)

Analysis of the internal heat losses in a thermoelectric generator

DEFF Research Database (Denmark)

Bjørk, Rasmus; Christensen, Dennis Valbjørn; Eriksen, Dan

2014-01-01

and radiative heat losses, including surface to surface radiation. For radiative heat losses it is shown that for the temperatures considered here, surface to ambient radiation is a good approximation of the heat loss. For conductive heat transfer the module efficiency is shown to be comparable to the case...... of radiative losses. Finally, heat losses due to internal natural convection in the module is shown to be negligible for the millimetre sized modules considered here. The combined case of radiative and conductive heat transfer resulted in the lowest efficiency. The optimized load resistance is found...... to decrease for increased heat loss. The leg dimensions are varied for all heat losses cases and it is shown that the ideal way to construct a TEG module with minimal heat losses and maximum efficiency is to either use a good insulating material between the legs or evacuate the module completely, and use...

Integration of Decentralized Thermal Storages Within District Heating (DH Networks

Directory of Open Access Journals (Sweden)

Schuchardt Georg K.

2016-12-01

Full Text Available Thermal Storages and Thermal Accumulators are an important component within District Heating (DH systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

Integrated heat transport simulation of high ion temperature plasma of LHD

International Nuclear Information System (INIS)

Murakami, S.; Yamaguchi, H.; Sakai, A.

2014-10-01

A first dynamical simulation of high ion temperature plasma with carbon pellet injection of LHD is performed by the integrated simulation GNET-TD + TASK3D. NBI heating deposition of time evolving plasma is evaluated by the 5D drift kinetic equation solver, GNET-TD and the heat transport of multi-ion species plasma (e, H, He, C) is studied by the integrated transport simulation code, TASK3D. Achievement of high ion temperature plasma is attributed to the 1) increase of heating power per ion due to the temporal increase of effective charge, 2) reduction of effective neoclassical transport with impurities, 3) reduction of turbulence transport. The reduction of turbulence transport is most significant contribution to achieve the high ion temperature and the reduction of the turbulent transport from the L-mode plasma (normal hydrogen plasma) is evaluated to be a factor about five by using integrated heat transport simulation code. Applying the Z effective dependent turbulent reduction model we obtain a similar time behavior of ion temperature after the C pellet injection with the experimental results. (author)

Integrating wind power using intelligent electric water heating

International Nuclear Information System (INIS)

Fitzgerald, Niall; Foley, Aoife M.; McKeogh, Eamon

2012-01-01

Dwindling fossil fuel resources and pressures to reduce greenhouse gas emissions will result in a more diverse range of generation portfolios for future electricity systems. Irrespective of the portfolio mix the overarching requirement for all electricity suppliers and system operators is to instantaneously meet demand, to operate to standards and reduce greenhouse gas emissions. Therefore all electricity market participants will ultimately need to use a variety of tools to balance the power system. Thus the role of demand side management with energy storage will be paramount to integrate future diverse generation portfolios. Electric water heating has been studied previously, particularly at the domestic level to provide load control, peak shave and to benefit end-users financially with lower bills, particularly in vertically integrated monopolies. In this paper a number of continuous direct load control demand response based electric water heating algorithms are modelled to test the effectiveness of wholesale electricity market signals to study the system benefits. The results are compared and contrasted to determine which control algorithm showed the best potential for energy savings, system marginal price savings and wind integration.

Application of fuel cells with heat recovery for integrated utility systems

Science.gov (United States)

Shields, V.; King, J. M., Jr.

1975-01-01

This paper presents the results of a study of fuel cell powerplants with heat recovery for use in an integrated utility system. Such a design provides for a low pollution, noise-free, highly efficient integrated utility. Use of the waste heat from the fuel cell powerplant in an integrated utility system for the village center complex of a new community results in a reduction in resource consumption of 42 percent compared to conventional methods. In addition, the system has the potential of operating on fuels produced from waste materials (pyrolysis and digester gases); this would provide further reduction in energy consumption.

Photovoltaic and Hydrogen Plant Integrated with a Gas Heat Pump for Greenhouse Heating: A Mathematical Study

Directory of Open Access Journals (Sweden)

Alexandros Sotirios Anifantis

2018-02-01

Full Text Available Nowadays, the traditional energy sources used for greenhouse heating are fossil fuels such as LPG, diesel and natural gas. The global energy demand will continue to grow and alternative technologies need to be developed in order to improve the sustainability of crop production in protected environments. Innovative solutions are represented by renewable energy plants such as photovoltaic, wind and geothermal integrated systems, however, these technologies need to be connected to the power grid in order to store the energy produced. On agricultural land, power grids are not widespread and stand-alone renewable energy systems should be investigated especially for greenhouse applications. The aim of this research is to analyze, by means of a mathematical model, the energy efficiency of a photovoltaic (8.2 kW, hydrogen (2.5 kW and ground source gas heat pump (2.2 kW integrated in a stand-alone system used for heating an experimental greenhouse tunnel (48 m2 during the winter season. A yearlong energy performance analysis was conducted for three different types of greenhouse cover materials, a single layer polyethylene film, an air inflated-double layer polyethylene film, and a double acrylic or polycarbonate. The results of one year showed that the integrated system had a total energy efficiency of 14.6%. Starting from the electric energy supplied by the photovoltaic array, the total efficiency of the hydrogen and ground source gas heat pump system was 112% if the coefficient of the performance of the heat pump is equal to 5. The heating system increased the greenhouse air temperatures by 3–9 °C with respect to the external air temperatures, depending on the greenhouse cover material used.

Simultaneous heat integration and techno-economic optimization of Organic Rankine Cycle (ORC) for multiple waste heat stream recovery

International Nuclear Information System (INIS)

Yu, Haoshui; Eason, John; Biegler, Lorenz T.; Feng, Xiao

2017-01-01

In the past decades, the Organic Rankine Cycle (ORC) has become a promising technology for low and medium temperature energy utilization. In refineries, there are usually multiple waste heat streams to be recovered. From a safety and controllability perspective, using an intermedium (hot water) to recover waste heat before releasing heat to the ORC system is more favorable than direct integration. The mass flowrate of the intermediate hot water stream determines the amount of waste heat recovered and the final hot water temperature affects the thermal efficiency of ORC. Both, in turn, exert great influence on the power output. Therefore, the hot water mass flowrate is a critical decision variable for the optimal design of the system. This study develops a model for techno-economic optimization of an ORC with simultaneous heat recovery and capital cost optimization. The ORC is modeled using rigorous thermodynamics with the concept of state points. The task of waste heat recovery using the hot water intermedium is modeled using the Duran-Grossmann model for simultaneous heat integration and process optimization. The combined model determines the optimal design of an ORC that recovers multiple waste heat streams in a large scale background process using an intermediate heat transfer stream. In particular, the model determines the optimal heat recovery approach temperature (HRAT), the utility load of the background process, and the optimal operating conditions of the ORC simultaneously. The effectiveness of this method is demonstrated with a case study that uses a refinery as the background process. Sensitivity of the optimal solution to the parameters (electricity price, utility cost) is quantified in this paper. - Highlights: • A new model for Organic Rankine cycle design optimization is presented. • Process heat integration and ORC are considered simultaneously. • Rigorous equation oriented models of the ORC are used for accurate results. • Impact of working

Internal Thermal Control System Hose Heat Transfer Fluid Thermal Expansion Evaluation Test Report

Science.gov (United States)

Wieland, P. O.; Hawk, H. D.

2001-01-01

During assembly of the International Space Station, the Internal Thermal Control Systems in adjacent modules are connected by jumper hoses referred to as integrated hose assemblies (IHAs). A test of an IHA has been performed at the Marshall Space Flight Center to determine whether the pressure in an IHA filled with heat transfer fluid would exceed the maximum design pressure when subjected to elevated temperatures (up to 60 C (140 F)) that may be experienced during storage or transportation. The results of the test show that the pressure in the IHA remains below 227 kPa (33 psia) (well below the 689 kPa (100 psia) maximum design pressure) even at a temperature of 71 C (160 F), with no indication of leakage or damage to the hose. Therefore, based on the results of this test, the IHA can safely be filled with coolant prior to launch. The test and results are documented in this Technical Memorandum.

Electricity and heat system development scenarios integrated in the energy system sustainable development in Romania in the period 2005 - 2025

International Nuclear Information System (INIS)

Marin, Otilia; Leca, Aureliu

2004-01-01

After 50 years of centralized economy, since 1989, Romania faces many challenges related to the internal conditions and to the new trends in energy markets over the world as: the existing low efficiency and availability, fast structural changes; the decentralization and privatization of the energy sector with new structures and entities; integration in EU and NATO structures. At present, with transition from the national vertical integrated monopolies to an open market, the determination of the global optimum development scenario of the power and heat sector becomes more important in order to find the policy which can lead the own strategies of different companies involved on market to a sustainable development of the society. The paper presents four long term development scenarios of the electricity and heat sector quantified from different points of view: technical, economical, environmental, social criteria, security of supply, risk diminishing etc and it continues by determining the long term global optimum development scenario integrated in the sustainable energy system. (authors)

Homotopy Perturbation Method for Thin Film Flow and Heat Transfer over an Unsteady Stretching Sheet with Internal Heating and Variable Heat Flux

Directory of Open Access Journals (Sweden)

I-Chung Liu

2012-01-01

Full Text Available We have analyzed the effects of variable heat flux and internal heat generation on the flow and heat transfer in a thin film on a horizontal sheet in the presence of thermal radiation. Similarity transformations are used to transform the governing equations to a set of coupled nonlinear ordinary differential equations. The obtained differential equations are solved approximately by the homotopy perturbation method (HPM. The effects of various parameters governing the flow and heat transfer in this study are discussed and presented graphically. Comparison of numerical results is made with the earlier published results under limiting cases.

COSO internal control integrated framework 2013

CERN Document Server

American Institute of Certified Public Accountants

2013-01-01

Issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO), the 2013 Internal Control – Integrated Framework(Framework) is expected to help organizations design and implement internal control in light of many changes in business and operating environments since the issuance of the original Framework in 1992. The new Framework retains the core definition of internal control and the five components of internal control, and it continues to emphasize the importance of management judgment in designing, implementing, and conducting a system of internal control, and in assessing its effectiveness. It broadens the application of internal control in addressing operations and reporting objectives, and clarifies the requirements for determining what constitutes effective internal control.

Process integration in bioprocess indystry: waste heat recovery in yeast and ethyl alcohol plant

International Nuclear Information System (INIS)

Raskovic, P.; Anastasovski, A.; Markovska, Lj.; Mesko, V.

2010-01-01

The process integration of the bioprocess plant for production of yeast and alcohol was studied. Preliminary energy audit of the plant identified the huge amount of thermal losses, caused by waste heat in exhausted process streams, and reviled the great potential for energy efficiency improvement by heat recovery system. Research roadmap, based on process integration approach, is divided on six phases, and the primary tool used for the design of heat recovery network was Pinch Analysis. Performance of preliminary design are obtained by targeting procedure, for three process stream sets, and evaluated by the economic criteria. The results of process integration study are presented in the form of heat exchanger networks which fulfilled the utilization of waste heat and enable considerable savings of energy in short payback period.

Heat transfer in window frames with internal cavities

Energy Technology Data Exchange (ETDEWEB)

Gustavsen, Arild

2001-07-01

Heat transfer in window frames with internal air cavities is studied in this thesis. Investigations focus on two- and three-dimensional natural convection effects inside air cavities, the dependence of the emissivity on the thermal transmittance, and the emissivity of anodized and untreated aluminium profiles. The investigations are mostly conducted on window frames which are the same size as real frames found in residential buildings. Numerical and experimental investigations were performed to study the effectiveness of one commercial Computational Fluid Dynamics (CFD) program for simulating combined natural convection and heat transfer in simple three-dimensional window frames with internal air cavities. The accuracy of the conjugate CFD simulations was evaluated by comparing results for surface temperature on the warm side of the specimens to results from experiments that use infrared (IR) thermography to map surface temperatures during steady-state thermal tests. In general, there was good agreement between the simulations and experiments. Two-dimensional computational fluid dynamic and conduction simulations are performed to study the difference between treating air cavities as a fluid and as a solid when calculating the thermal transmittance of window frames. The simulations show that traditional software codes, simulating only conduction and using equivalent conductivities for the air cavities, give Uvalues that compare well with results from fluid flow simulations. The difference between the two models are mostly limited to the temperature distribution inside air cavities. It is also found that cavities with an interconnection less than about 7 mm can be treated as separate cavities. Three-dimensional natural convection effects in simple and custom-made PVC and thermally broken aluminum window frames with one open internal cavity were studied, with the use of CFD simulations and thermography experiments. Focus was put on corner effects and heat transfer

International symposium on radiative heat transfer: Book of abstracts

International Nuclear Information System (INIS)

1995-01-01

The international symposium on radiative heat transfer was held on 14-18 August 1995 Turkey. The specialists discussed radiation transfer in materials processing and manufacturing, solution of radiative heat transfer equation, transient radiation problem and radiation-turbulence interactions, raditive properties of gases, atmospheric and stellar radiative transfer , radiative transfer and its applications, optical and radiative properties of soot particles, inverse radiation problems, partticles, fibres,thermophoresis and waves and modelling of comprehensive systems at the meeting. Almost 79 papers were presented in the meeting

Energy and exergy analyses of an integrated solar heat pump system

International Nuclear Information System (INIS)

Suleman, F.; Dincer, I.; Agelin-Chaab, M.

2014-01-01

An integrated solar and heat pump based system for industrial heating is developed in this study. The system comprises heat pump cycle for process heating water and solar energy for another industrial heating process. Comprehensive energy and exergy analyses are performed on the system. These analyses generated some compelling results as expected because of the use of green and environmentally friendly energy sources. The results show that the energy efficiency of the process is 58% while the exergy efficiency is 75%. Energetic COP of the heat pump cycle is 3.54 whereas the exergy efficiency is 42.5%. Moreover, the energetic COP of the system is 2.97 and the exergy efficiency of the system is 35.7%. In the parametric study, a different variation such as changing the temperature and pressure of the condenser also shows positive results. - Highlights: • An integrated system is analysed using renewable energy source which can be used in textile industry. • Energy losses and exergy destructions are calculated at all major components. • Energy and exergy efficiencies of all subunits, subsystems and overall system are determined. • A parametric study shows the effect of environment and operating conditions on efficiencies. • Solar energy for heating in textile industry is efficient and environmentally friendly

An Internally Heated Shape Memory Polymer Dry Adhesive

Directory of Open Access Journals (Sweden)

Jeffrey Eisenhaure

2014-08-01

Full Text Available A conductive epoxy-based shape memory polymer (SMP is demonstrated using carbon black (CB as a dopant for the purpose of creating an SMP dry adhesive system which can internally generate the heat required for activation. The electrical and mechanical properties of the CB/SMP blends for varying dopant concentrations are characterized. A composite adhesive is created to minimize surface contact resistance to conductive tape acting as electrodes, while maintaining bulk resistivity required for heat generation due to current flow. The final adhesive can function on flat or curved surfaces. As a demonstration, a 25 mm wide by 45 mm long dry adhesive strip is shown to heat evenly from an applied voltage, and can easily hold a mass in excess of 6 kg when bonded to a spherical concave glass surface using light pressure at 75 °C.

Heat integration in processes with diverse production lines: A comprehensive framework and an application in food industry

International Nuclear Information System (INIS)

Miah, J.H.; Griffiths, A.; McNeill, R.; Poonaji, I.; Martin, R.; Yang, A.; Morse, S.

2014-01-01

Highlights: • A new practical heat integration framework was developed for complex and diverse production lines. • Heat recovery was maximised by direct and indirect heat integration at zonal and factory levels. • A novel approach to stream data extraction was proposed to account for both stream capacity and availability. • A case study was carried out on a multi-product confectionery factory. - Abstract: Heat integration is a key measure to improving energy efficiency and maximising heat recovery. Since the advent of Pinch analysis in the 1980s, direct and indirect integration approaches have developed in separate domains with very few examples where both approaches are utilised together to maximise heat recovery. This paper presents a novel decision-making framework for heat integration in complex and diverse production lines, with the aim to provide the user with a step-by-step guide to evaluate all heat recovery opportunities through a combination of direct and indirect heat integration. This framework involves analysis at both the zonal level and the factory level. The proposed framework was applied to a case study based on a confectionery factory in the UK that manufactured multiple products across a diverse range of food technologies. It demonstrates that the framework can effectively identify the significant streams to be considered in the heat integration analysis, and address practical factors such as diverse production times, geographical proximity, and potential of compromise to product quality when the direct and indirect heat integration opportunities are proposed and assessed both within and between production zones. This practical framework has the potential to benefit the wider food industry and beyond

Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

International Nuclear Information System (INIS)

Lythcke-Jørgensen, Christoffer; Haglind, Fredrik; Clausen, Lasse R.

2014-01-01

Highlights: • We model a system where lignocellulosic ethanol production is integrated with a combined heat and power (CHP) plant. • We conduct an exergy analysis for the ethanol production in six different system operation points. • Integrated operation, district heating (DH) production and low CHP loads all increase the exergy efficiency. • Separate operation has the largest negative impact on the exergy efficiency. • Operation is found to have a significant impact on the exergy efficiency of the ethanol production. - Abstract: Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible, and a gas boiler is used as back-up when integration is not possible. The system was evaluated according to six operation points that alternate on the following three different operation parameters: Load in the CHP unit, integrated versus separate operation, and inclusion of district heating production in the ethanol facility. The calculated standard exergy efficiency of the ethanol facility varied from 0.564 to 0.855, of which the highest was obtained for integrated operation at reduced CHP load and full district heating production in the ethanol facility, and the lowest for separate operation with zero district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the

Performance analysis of an organic Rankine cycle with internal heat exchanger having zeotropic working fluid

Directory of Open Access Journals (Sweden)

Thoranis Deethayat

2015-09-01

Full Text Available In this study, performance of a 50 kW organic Rankine cycle (ORC with internal heat exchanger (IHE having R245fa/R152a zeotropic refrigerant with various compositions was investigated. The IHE could reduce heat rate at the ORC evaporator and better cycle efficiency could be obtained. The zeotropic mixture could reduce the irreversibilities during the heat exchanges at the ORC evaporator and the ORC condenser due to its gliding temperature; thus the cycle working temperatures came closer to the temperatures of the heat source and the heat sink. In this paper, effects of evaporating temperature, mass fraction of R152a and effectiveness of internal heat exchanger on the ORC performances for the first law and the second law of thermodynamics were considered. The simulated results showed that reduction of R245fa composition could reduce the irreversibilities at the evaporator and the condenser. The suitable composition of R245fa was around 80% mass fraction and below this the irreversibilities were nearly steady. Higher evaporating temperature and higher internal heat exchanger effectiveness also increased the first law and second law efficiencies. A set of correlations to estimate the first and the second law efficiencies with the mass fraction of R245fa, the internal heat exchanger effectiveness and the evaporating temperature were also developed.

Design and analysis of heat exchanger networks for integrated Ca-looping systems

International Nuclear Information System (INIS)

Lara, Yolanda; Lisbona, Pilar; Martínez, Ana; Romeo, Luis M.

2013-01-01

Highlights: • Heat integration is essential to minimize energy penalties in calcium looping cycles. • A design and analysis of four heat exchanger networks is stated. • New design with higher power, lower costs and lower destroyed exergy than base case. - Abstract: One of the main challenges of carbon capture and storage technologies deals with the energy penalty associated with CO 2 separation and compression processes. Thus, heat integration plays an essential role in the improvement of these systems’ efficiencies. CO 2 capture systems based on Ca-looping process present a great potential for residual heat integration with a new supercritical power plant. The pinch methodology is applied in this study to define the minimum energy requirements of the process and to design four configurations for the required heat exchanger network. The Second Law of Thermodynamics represents a powerful tool for reducing the energy demand since identifying the exergy losses of the system serves to allocate inefficiencies. In parallel, an economic analysis is required to asses the cost reduction achieved by each configuration. This work presents a combination of pinch methodology with economic and exergetic analyses to select the more appropriate configuration of heat exchanger network. The lower costs and minor destroyed exergy obtained for the best proposed network result in a of 0.91% global energy efficiency increase

Thermodynamic analysis of application of organic Rankine cycle for heat recovery from an integrated DIR-MCFC with pre-reformer

International Nuclear Information System (INIS)

Vatani, Ali; Khazaeli, Ali; Roshandel, Ramin; Panjeshahi, Mohammad Hassan

2013-01-01

Highlights: ► Using an integrated pre-reformer before feeding a DIR-MCFC is proposed. ► An ORC with different working fluid is used for waste heat recovery from the proposed plant. ► Performance of compound system is evaluated by thermodynamic analysis. ► An improvement on simultaneously heat integration between the units and waste heat recovery is performed. ► Overall energy and exergy efficiencies are found to be 60.45% and 57.75%. - Abstract: This work deals with waste heat recovery from a proposed direct internal reforming molten carbonate fuel cell (DIR-MCFC), including an integrated pre-reformer. In this regard, some advantages are attainable over exhaust gas recycling. For instance, due to low temperature in the pre-reformer, carbon deposition and coke formation resulting from higher hydrocarbons can be eliminated. In this study, the cathode outlet provides the heat requirement for the pre-reforming process. After partial heat recovery from the cathode outlet, the stream still has a considerable energy and exergy (352.55 °C and 83.687 kW respectively). This study investigates waste heat recovery from the proposed DIR-MCFC, using an organic Rankine cycle (ORC) with two different configurations. In the first case, the cathode outlet provides the heat requirement for the pre-reforming process; then, it enters the heat recovery vapor generator of the organic Rankine cycle. In the second case, the cathode outlet is split into two streams for using in an ORC and supplying the pre-reforming process required heat. Several substances are selected as working fluids in order to compare their performance in the waste heat recovery system. The overall results at optimum conditions indicate that the energy and exergy efficiencies of the compound system are increased and its exergy loss is decreased with cathode splitting for all substances (1.1% average over all fluids). It is concluded that cathode splitting has a significant impact on the substances which

Total Site Heat Integration Considering Pressure Drops

Directory of Open Access Journals (Sweden)

Kew Hong Chew

2015-02-01

Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

Combined Heat and Power Dispatch Considering Heat Storage of Both Buildings and Pipelines in District Heating System for Wind Power Integration

Directory of Open Access Journals (Sweden)

Ping Li

2017-06-01

Full Text Available The strong coupling between electric power and heat supply highly restricts the electric power generation range of combined heat and power (CHP units during heating seasons. This makes the system operational flexibility very low, which leads to heavy wind power curtailment, especially in the region with a high percentage of CHP units and abundant wind power energy such as northeastern China. The heat storage capacity of pipelines and buildings of the district heating system (DHS, which already exist in the urban infrastructures, can be exploited to realize the power and heat decoupling without any additional investment. We formulate a combined heat and power dispatch model considering both the pipelines’ dynamic thermal performance (PDTP and the buildings’ thermal inertia (BTI, abbreviated as the CPB-CHPD model, emphasizing the coordinating operation between the electric power and district heating systems to break the strong coupling without impacting end users’ heat supply quality. Simulation results demonstrate that the proposed CPB-CHPD model has much better synergic benefits than the model considering only PDTP or BTI on wind power integration and total operation cost savings.

Optimal Operation System of the Integrated District Heating System with Multiple Regional Branches

Science.gov (United States)

Kim, Ui Sik; Park, Tae Chang; Kim, Lae-Hyun; Yeo, Yeong Koo

This paper presents an optimal production and distribution management for structural and operational optimization of the integrated district heating system (DHS) with multiple regional branches. A DHS consists of energy suppliers and consumers, district heating pipelines network and heat storage facilities in the covered region. In the optimal management system, production of heat and electric power, regional heat demand, electric power bidding and sales, transport and storage of heat at each regional DHS are taken into account. The optimal management system is formulated as a mixed integer linear programming (MILP) where the objectives is to minimize the overall cost of the integrated DHS while satisfying the operation constraints of heat units and networks as well as fulfilling heating demands from consumers. Piecewise linear formulation of the production cost function and stairwise formulation of the start-up cost function are used to compute nonlinear cost function approximately. Evaluation of the total overall cost is based on weekly operations at each district heat branches. Numerical simulations show the increase of energy efficiency due to the introduction of the present optimal management system.

Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

DEFF Research Database (Denmark)

Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

2013-01-01

produces ethanol, solid biofuel, molasses, and is able to produce district heating hot water. Considering all products equally valuable, the exergy efficiency of the ethanol facility was found to be 0.790 during integrated operation with zero district heating production, and 0.852 during integrated...

First results of out-of-pile experiments concerning cooling phenomena of molten layers with internal heat sources

International Nuclear Information System (INIS)

Fieg, G.

1977-01-01

After severe hypothetical reactor accidents, large amounts of molten core material with internal heat generation may appear. It must be guaranteed that these materials can be kept within the containment. To clarify this situation, the knowledge of heat transport from liquid layers with internal heat generation is needed. First experimental results on heat transport from internally heated horizontal fluid layers are presented. The experiments have been performed in a smooth horizontal vessel with the base of 15 x 15 cm 2 . The Joule-heated liquid layer (depth L = 1 cm - 3.5 cm) is enclosed between two isothermal horizontal walls. They are polished fore parts of heat exchangers. The temperatures of the walls were held constant with thermostatically controlled water circulating through the heat exchangers. Horizontal heat fluxes were depressed by appropriate insulation of the side walls. The total heat transport to the upper and lower boundaries has been measured by the mass transport through the heat exchangers and the temperature rise of the cooling water

Consistency among integral measurements of aggregate decay heat power

Energy Technology Data Exchange (ETDEWEB)

Takeuchi, H.; Sagisaka, M.; Oyamatsu, K.; Kukita, Y. [Nagoya Univ. (Japan)

1998-03-01

Persisting discrepancies between summation calculations and integral measurements force us to assume large uncertainties in the recommended decay heat power. In this paper, we develop a hybrid method to calculate the decay heat power of a fissioning system from those of different fissioning systems. Then, this method is applied to examine consistency among measured decay heat powers of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U and {sup 239}Pu at YAYOI. The consistency among the measured values are found to be satisfied for the {beta} component and fairly well for the {gamma} component, except for cooling times longer than 4000 s. (author)

Internal heat gain from different light sources in the building lighting systems

Directory of Open Access Journals (Sweden)

Suszanowicz Dariusz

2017-01-01

Full Text Available EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

Internal heat gain from different light sources in the building lighting systems

Science.gov (United States)

Suszanowicz, Dariusz

2017-10-01

EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output) were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

Performance Characteristics of a Modularized and Integrated PTC Heating System for an Electric Vehicle

Directory of Open Access Journals (Sweden)

Yoon Hyuk Shin

2015-12-01

Full Text Available A modularized positive temperature coefficient heating system has controller-integrated heater modules. Such a heating system that uses a high-voltage power of 330 V was developed in the present study for use in electric vehicles. Four heater modules and one controller with an input power of 5.6 kW were integrated in the modularized system, which was designed for improved heating power density and light weight compared to the conventional heating system, in which the controller is separated. We experimentally investigated the performance characteristics, namely, the heating capacity, energy efficiency, and pressure drop, of a prototype of the developed heating system and found it to have satisfactory performance. The findings of this study will contribute to the development of heating systems for electric vehicles.

A novel split cycle internal combustion engine with integral waste heat recovery

International Nuclear Information System (INIS)

Dong, Guangyu; Morgan, Robert; Heikal, Morgan

2015-01-01

Highlights: • A novel engine thermodynamic cycle is proposed. • Theoretical analysis is applied to identify the key parameters of the thermodynamic cycle. • The key stages of the split cycle are analysed via one-dimensional modelling work. • The effecting mechanism of the split cycle efficiency is analysed. - Abstract: To achieve a step improvement in engine efficiency, a novel split cycle engine concept is proposed. The engine has separate compression and combustion cylinders and waste heat is recovered between the two. Quasi-isothermal compression of the charge air is realised in the compression cylinder while isobaric combustion of the air/fuel mixture is achieved in the combustion cylinder. Exhaust heat recovery between the compression and combustion chamber enables highly efficient recovery of waste heat within the cycle. Based on cycle analysis and a one-dimensional engine model, the fundamentals and the performance of the split thermodynamic cycle is estimated. Compared to conventional engines, the compression work can be significantly reduced through the injection of a controlled quantity of water in the compression cylinder, lowering the gas temperature during compression. Thermal energy can then be effectively recovered from the engine exhaust in a recuperator between the cooled compressor cylinder discharge air and the exhaust gas. The resulting hot high pressure air is then injected into a combustor cylinder and mixed with fuel, where near isobaric combustion leads to a low combustion temperature and reduced heat transferred from the cylinder wall. Detailed cycle simulation indicates a 32% efficiency improvement can be expected compared to the conventional diesel engines.

Is Swedish district heating operating on an integrated market? – Differences in pricing, price convergence, and marketing strategy between public and private district heating companies

International Nuclear Information System (INIS)

Åberg, M.; Fälting, L.; Forssell, A.

2016-01-01

The deregulation of the Swedish electricity market in 1996 made it possible to operate municipal district heating commercially. Until that time district heating had been organized mainly as municipal utilities. After 1996 district heating is instead expected to function on a market. In competitive and integrated markets, prices are expected to be equal, or converging. To find out if district heating operates on an integrated market the differences in price levels, price convergence, price strategy, and business goals, among municipal, private and state owned district heating companies are investigated. Price statistics was used along with results from a questionnaire that was answered by representatives for 109 Swedish district heating companies. The results show that prices among district heating systems do not converge significantly and that variations in prices among municipal systems are larger than among private and state owned systems. Furthermore, despite the fact that district heating is supposed to be commercial, a vast majority of district heating companies apply cost-based pricing and not market pricing. The municipal companies give priority to political goals before financial goals. The conclusion is that a Swedish integrated market for heat has not yet evolved, and some district heating price-controlling mechanism is necessary. - Highlights: • Price statistics and owner type data were used along with results from a questionnaire. • Results show that prices among district heating systems do not converge. • Municipal district heating companies still apply cost-based pricing to a large extent. • District heating companies are not operating on an integrated market for heat. • Some price-controlling mechanism for district heating is necessary.

Network model of free convection within internally heated porous media

International Nuclear Information System (INIS)

Conrad, P.W.

1977-01-01

A hypothetical core-disruptive accident (HCDA) in a liquid metal fast breeder reactor (LMFBR) may result in the formation of an internally heated debris bed. Considerable attention has been given to postulated mechanisms by which such beds may be cooled. It is the purpose of the work described to demonstrate a method for computing the heat transfer from such a bed to the overlying sodium pool due to single-phase, free convection

Biodiesel production process from microalgae oil by waste heat recovery and process integration.

Science.gov (United States)

Song, Chunfeng; Chen, Guanyi; Ji, Na; Liu, Qingling; Kansha, Yasuki; Tsutsumi, Atsushi

2015-10-01

In this work, the optimization of microalgae oil (MO) based biodiesel production process is carried out by waste heat recovery and process integration. The exergy analysis of each heat exchanger presented an efficient heat coupling between hot and cold streams, thus minimizing the total exergy destruction. Simulation results showed that the unit production cost of optimized process is 0.592$/L biodiesel, and approximately 0.172$/L biodiesel can be avoided by heat integration. Although the capital cost of the optimized biodiesel production process increased 32.5% and 23.5% compared to the reference cases, the operational cost can be reduced by approximately 22.5% and 41.6%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental investigations of heat transfer from an internally finned two phase closed thermosyphon

International Nuclear Information System (INIS)

Naresh, Y.; Balaji, C.

2017-01-01

Highlights: • Experimental investigations on an internally finned vertical thermosyphon. • Two fluids – water and acetone considered. • Optimum fill ratio determined to be 50%. • Addition of internal fins at the condenser leads to improved thermal performance. - Abstract: This paper reports the results of an experimental investigation of heat transfer from an internally finned thermosyphon charged with either water or acetone. Six constant area fins with a rectangular cross section are placed internally along the length at the condenser section. The ratio of initial liquid pool volume to the evaporator volume, known as the filling ratio in a thermosyphon system, has been varied in this study. Experiments are carried out for filling ratios of 20, 50, and 80% for two working fluids (i) water and (ii) acetone. Results show that a fill ratio of 50% gives better heat transfer performance. Providing internal fins at the condenser produces additional condensation which improves the thermal performance of the thermosyphon by 17% in terms of the temperature reduction at the source and sink and 35.48% in terms of reduction in thermal resistance at lower heat inputs. The thermosyphon is tested between power levels of 50 and 275 W.

Abstracts of international symposium on heat and mass transfer under plasma conditions

International Nuclear Information System (INIS)

1994-01-01

The international symposium on heat and mass transfer under plasma conditions was held on 4-8 July 1994 in Cesme, Izmir, Turkey. The spesialists discussed heat and mass transfer in the field of plasma processing at the meeting. More than 70 papers were presented in the meeting

Abstracts of international symposium on heat and mass transfer under plasma conditions

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

The international symposium on heat and mass transfer under plasma conditions was held on 4-8 July 1994 in Cesme, Izmir, Turkey. The spesialists discussed heat and mass transfer in the field of plasma processing at the meeting. More than 70 papers were presented in the meeting.

Effect of rotational speed modulation on heat transport in a fluid layer with temperature dependent viscosity and internal heat source

Directory of Open Access Journals (Sweden)

B.S. Bhadauria

2014-12-01

Full Text Available In this paper, a theoretical investigation has been carried out to study the combined effect of rotation speed modulation and internal heating on thermal instability in a temperature dependent viscous horizontal fluid layer. Rayleigh–Bénard momentum equation with Coriolis term has been considered to describe the convective flow. The system is rotating about it is own axis with non-uniform rotational speed. In particular, a time-periodic and sinusoidally varying rotational speed has been considered. A weak nonlinear stability analysis is performed to find the effect of modulation on heat transport. Nusselt number is obtained in terms of amplitude of convection and internal Rayleigh number, and depicted graphically for showing the effects of various parameters of the system. The effect of modulated rotation speed is found to have a stabilizing effect for different values of modulation frequency. Further, internal heating and thermo-rheological parameters are found to destabilize the system.

Operating Reserves and Wind Power Integration: An International Comparison; Preprint

Energy Technology Data Exchange (ETDEWEB)

Milligan, M.; Donohoo, P.; Lew, D.; Ela, E.; Kirby, B.; Holttinen, H.; Lannoye, E.; Flynn, D.; O' Malley, M.; Miller, N.; Eriksen, P. B.; Gottig, A.; Rawn, B.; Gibescu, M.; Lazaro, E. G.; Robitaille, A.; Kamwa, I.

2010-10-01

This paper provides a high-level international comparison of methods and key results from both operating practice and integration analysis, based on an informal International Energy Agency Task 25: Large-scale Wind Integration.

Integrating Solar Heating into an Air Handling Unit to Minimize Energy Consumption

OpenAIRE

Wilson, Scott A

2010-01-01

The purpose of this project was to test a method of integrating solar heating with a small commercial air handling unit (AHU). In order to accomplish this a heat exchanger was placed in the reheat position of the AHU and piped to the solar heating system. This heat exchanger is used to supplement or replace the existing electric reheat. This method was chosen for its ability to utilize solar energy on a more year round basis when compared to a traditional heating system. It allows solar h...

Heat integration of fractionating systems in para-xylene plants based on column optimization

International Nuclear Information System (INIS)

Chen, Ting; Zhang, Bingjian; Chen, Qinglin

2014-01-01

In this paper, the optimization of xylene fractionation and disproportionation units in a para-xylene plant is performed through a new method for systematic design based on GCC (grand composite curve) and CGCC (column grand composite curve). The distillation columns are retrofitted by CGCC firstly. Heat Integration between the columns and the background xylene separation process are then explored by GCC. We found that potential retrofits for columns suggested by CGCC provide better possibilities for further Heat Integration. The effectiveness of the retrofits is finally evaluated by means of thermodynamics and economic analysis. The results show that energy consumption of the retrofitted fractionating columns decreases by 7.13 MW. With the improved thermodynamic efficiencies, all columns operate with less energy requirements. Coupled with Heat Integration, the energy input of the para-xylene plant is reduced by 30.90 MW, and the energy outputs are increased by 17 MW and 58 MW for generation of the 3.5 MPa and 2.5 MPa steams. The energy requirement after the Heat Integration is reduced by 12% compared to the original unit. The retrofits required a fixed capital cost of 6268.91 × 10 3  $ and saved about 24790.74 × 10 3  $/year worth of steam. The payback time is approximately 0.26 year for the retrofits. - Highlights: • A new method for systematic design is proposed to improve energy saving of the PX plant in retrofit scenarios. • An optimization approach is developed to identify maximum heat recovery in distillation columns. • An efficient Heat Integration procedure of the PX plant is addressed based on the optimal retrofitted distillation columns. • The energy consumption is reduced by 12% after improvement to an industrial case

Towards an integrated model of international migration

Directory of Open Access Journals (Sweden)

Douglas S. MASSEY

2012-12-01

Full Text Available Demographers have yet to develop a suitable integrated model of international migration and consequently have been very poor at forecasting immigration. This paper outlines the basic elements of an integrated model and surveys recent history to suggest the key challenges to model construction. A comprehensive theory must explain the structural forces that create a supply of people prone to migrate internationally, the structural origins of labour demand in receiving countries, the motivations of those who respond to these forces by choosing to migrate internationally, the growth and structure of transnational networks that arise to support international movement, the behaviour states in response to immigrant flows, and the influence of state actions on the behaviour of migrants. Recent history suggests that a good model needs to respect the salience of markets, recognize the circularity of migrant flows, appreciate the power of feedback effects, and be alert unanticipated consequences of policy actions.

Determination of Factors Related to Students' Understandings of Heat, Temperature and Internal Energy Concepts

Science.gov (United States)

Gurcay, Deniz; Gulbas, Etna

2018-01-01

The purpose of this research is to investigate the relationships between high school students' learning approaches and logical thinking abilities and their understandings of heat, temperature and internal energy concepts. Learning Approach Questionnaire, Test of Logical Thinking and Three-Tier Heat, Temperature and Internal Energy Test were used…

Heat-pump-centered integrated community energy systems: system development summary

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1980-02-01

An introduction to district heating systems employing heat pumps to enable use of low-temperature energy sources is presented. These systems operate as thermal utilities to provide space heating and may also supply space cooling, service-water heating, and other thermal services. Otherwise-wasted heat from industrial and commercial processes, natural sources including solar and geothermal heat, and heat stored on an annual cycle from summer cooling may be effectively utilized by the systems described. These sources are abundant, and their use would conserve scarce resources and reduce adverse environmental impacts. More than one-quarter of the energy consumed in the United States is used to heat and cool buildings and to heat service water. Natural gas and oil provide approximately 83% of this energy. The systems described show potential to reduce net energy consumption for these services by 20 to 50% and to allow fuel substitution with less-scarce resources not practical in smaller, individual-building systems. Seven studies performed for the system development phase of the Department of Energy's Heat-Pump-Centered Integrated Community Energy Systems Project and to related studies are summarized. A concluding chapter tabulates data from these separately published studies.

Internal (Annular) and Compressible External (Flat Plate) Turbulent Flow Heat Transfer Correlations.

Energy Technology Data Exchange (ETDEWEB)

Dechant, Lawrence [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, Justin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-01-01

Here we provide a discussion regarding the applicability of a family of traditional heat transfer correlation based models for several (unit level) heat transfer problems associated with flight heat transfer estimates and internal flow heat transfer associated with an experimental simulation design (Dobranich 2014). Variability between semi-empirical free-flight models suggests relative differences for heat transfer coefficients on the order of 10%, while the internal annular flow behavior is larger with differences on the order of 20%. We emphasize that these expressions are strictly valid only for the geometries they have been derived for e.g. the fully developed annular flow or simple external flow problems. Though, the application of flat plate skin friction estimate to cylindrical bodies is a traditional procedure to estimate skin friction and heat transfer, an over-prediction bias is often observed using these approximations for missile type bodies. As a correction for this over-estimate trend, we discuss a simple scaling reduction factor for flat plate turbulent skin friction and heat transfer solutions (correlations) applied to blunt bodies of revolution at zero angle of attack. The method estimates the ratio between axisymmetric and 2-d stagnation point heat transfer skin friction and Stanton number solution expressions for sub-turbulent Reynolds numbers %3C1x10 4 . This factor is assumed to also directly influence the flat plate results applied to the cylindrical portion of the flow and the flat plate correlations are modified by

Numerical Investigation of Turbulent Natural Convection Heat Transfer in an Internally-Heated Melt Pool and Metallic Layer

International Nuclear Information System (INIS)

Nourgaliev, R.R.; Dinh, A.T.; Dinh, T.N.; Sehgal, B.R.

1999-01-01

This paper presents results of numerical investigation of turbulent natural convection in an internally-heated oxidic pool, and in a metallic layer heated from below and cooled from top and sidewalls. Emphasis is placed upon applicability of the existing heat transfer correlations (obtained from simulant-material experiments) in assessments of a prototypic severe reactor accident. The objectives of this study are (i) to improve the current understanding of the physics of unstably stratified flows, and (ii) to reduce uncertainties associated with modeling and assessment of natural convection heat transfer in the above configuration. Prediction capabilities of different turbulence modeling approaches are first examined and discussed, based on extensive results of numerical investigations performed by present authors. Findings from numerical modeling of turbulent natural convection flow and heat transfer in melt pools and metallic layers are then described. (authors)

Assessment of integrity for the pressure vessel internals of PWRs under blowdown loadings

International Nuclear Information System (INIS)

Geiss, M.; Benner, J.; Ludwig, A.

1984-01-01

In safety analysis of pressurized water reactors the loss-of-coolant accident plays a central role. Thereby a sudden break of a cold primary coolant pipe close to the reactor pressure vessel is postulated. The sudden pressure release of the primary system (blowdown) causes high dynamic loading on the pressure vessel internals. The resulting deformations must not impair shut down of the reactor and decay heat removal in an inadmissible way. For this assessment a blowdown analysis for a 1300 MW pressurized water reactor is carried out. These investigations are completed with a detailed stress analysis for the highly loaded core barrel clamping. The results show that the reactor pressure vessel internals are able to withstand blowdown loading. Even in case of a sudden and complete break of the primary coolant pipe the loading has to be twice as high to endanger the structural integrity. (orig.) [de

Integration of solar installations in heating technology; Integration der Solaranlage in die Heizungstechnik

Energy Technology Data Exchange (ETDEWEB)

Jaeger, H. [Solvis Energiesysteme GmbH und Co KG, Braunschweig (Germany)

1998-06-01

Future heating systems must be geared to the task of providing the comfort of warm rooms and warm water while giving due consideration to the consequences this has for the environment. The present paper discusses the development of heating energy demand, the integration and adjustment of the heating circuit for solar energy, and the dimensioning and layout of a solar installation for water warming. It also deals with the testing of solar buffer storages. [Deutsch] Wie kann der Komfort warmer Raeume und warmem Wassers erreicht werden und welche Konsquenzen hat das fuer die Umwelt, dies sind die Kriterien an denen sich die Waermeversorgung der Zukunft orientieren muss. Die Entwicklung des Heizenergiebedarfs, die Einbindung und Abstimmung des Heizkrieses fuer Solarenergie sowie die Dimensionierung und Auslegung einer Solaranlage zur Warmwassererw armung werden erlaeutert. Ein weiterer Punkt betrifft den Test von Solarpufferspeichern.

House-internal heating systems; Husinterna vaermesystem

Energy Technology Data Exchange (ETDEWEB)

Johansson, Per-Olof; Wollerstrand, Janusz [Lund Univ. (Sweden). Dept. of Heat and Power Engineering

2005-07-01

In this report the placement of the circulation-pump in of waterborne radiator systems, as well as their filling and deairation are investigated. The study was done by literature studies and interviews with consultants and companies active on the HVAC-market. It was concluded that different placements of the pump in relationship to the heat exchanger exist, and the arguments for the choice of placement are varying. The main explanation of the choice of placement is that it is based on experience/or by practical reasons. The most important factor influencing the placement of the pump found, was how the pump is situated in relation to the expansion-tank. To maintain pressure in the whole system the expansion-tank should be placed on the suction side of the pump without any intermediate pressure-dropping devices in between. This placement ensures overpressure in the whole radiator-system and reduces the risk of unwanted leak in of air. To avoid cavitation sufficient static pressure on the suction side of the pump is necessary. The pressure increases with the temperature, which must be taken into consideration if the pump is placed on the warm side of the heat-exchanger. From this point of view a placement in the return-pipe from the radiator-system is to be preferred. Before advices for HVAC-branch regarding placement of the circulation-pump in the heating systems can be implemented, it is of big importance to analyse and clearly specify the advantages and disadvantages of a certain placement of the pump. There is a need of directions to get house-internal systems to operate properly together with district heating system. This is especially important when older heating systems with burners and shunt valves are being connected. Filling and deairation of the radiator system is of great importance for the function of the system. A radiator-system with significant level of air remains is difficult to adjust and will not work properly. Air in the radiators leads to

Data for occupancy internal heat gain calculation in main building categories

Directory of Open Access Journals (Sweden)

Kaiser Ahmed

2017-12-01

Full Text Available Heat losses from occupant body by means of convection, radiation, vapor, and sweat are essential data for indoor climate and energy simulations. Heat losses depend on the metabolic activity and body surface area. Higher variations of body surface area of occupants are observed in day care centers, kinder gardens and schools compared to other building categories (Tables 2 and 3 and these variations need to be accounted, otherwise in these building categories heat gains, CO2 and humidity generation are overestimated. Indoor temperature, humidity level, air velocity, and clothing insulation have significant influences on dry and total heat losses from occupant body leading to typical values for summer and winter. The data presented in this article are related to the research article entitled Occupancy schedules for energy simulation in new prEN16798-1 and ISO/FDIS 17772-1 standards (Ahmed et al., 2017 [1]. Keywords: Body surface area, Metabolic rate, Dry heat loss, Total heat loss, Internal heat gain

The international heat pump market as seen from the 'Business Development' point of view

International Nuclear Information System (INIS)

Schilli, A. S.; Afjei, T.

2002-01-01

This article takes a close look at the prerequisites that are decisive for successful business development in the international heat pump market and the challenges placed by them. The article examines the quality of market information and data that is available, especially regarding the market potential for heating and cooling in residential, commercial and industrial buildings. The results of various national and international surveys and studies made in this area are discussed. Several characteristics of the heat pump market - both in the buying and selling areas - are examined in order to clarify the requirements for market and business development in these sectors

Vertical integration of local fuel producers into rural district heating systems – Climate impact and production costs

International Nuclear Information System (INIS)

Kimming, M.; Sundberg, C.; Nordberg, Å.; Hansson, P.-A.

2015-01-01

Farmers can use their own agricultural biomass residues for heat production in small-scale systems, enabling synergies between the district heating (DH) sector and agriculture. The barriers to entry into the Swedish heat market were extremely high as long as heat distribution were considered natural monopoly, but were recently lowered due to the introduction of a regulated third party access (TPA) system in the DH sector. This study assesses the potential impact on greenhouse gas emissions and cost-based heat price in the DH sector when farmers vertically integrate into the heat supply chain and introduce more local and agricultural crops and residues into the fuel mix. Four scenarios with various degree of farmer integration, were assessed using life cycle assessment (LCA) methodology, and by analysis of the heat production costs. The results show that full integration of local farm and forest owners in the value chain can reduce greenhouse gas emissions and lower production costs/heat price, if there is an incentive to utilise local and agricultural fuels. The results imply that farmer participation in the DH sector should be encouraged by e.g. EU rural development programmes. - Highlights: • Five DH production systems based on different fuels and ownership were analysed. • Lower GHG emissions were obtained when farmers integrate fully into the DH chain. • Lower heat price was obtained by full vertical integration of farmers. • Salix and straw-based production resulted in the lowest GHG and heat price

Design consideration for a diversity of heat sink

Energy Technology Data Exchange (ETDEWEB)

Rueckbrodt, Karin; Meischak, Stefan [AREVA NP GmbH, Erlangen (Germany)

2013-07-01

The defense in depth approach requires in all cases to prevent and mitigate accidents that could release radioactive materials. To assure the physical design barriers (preserve fuel integrity, reactor coolant pressure boundary integrity, and containment integrity) the decay heat has to be removed. External and internal events have to be taken in consideration for the robustness of all the involved cooling systems. To ensure the cooling function in all conceivable and all unlikely events an analysis for the necessity of a diversified heat sink is essential. The diversified concepts analyses the type of the primary heat sink and use contrary sources for the heat sink, air instead of water, well instead of a river. A complete diversity is realized if also for the heat transfer diversified systems are implemented. The described solutions are mainly applied for BWR plants, but can be partly transferred analogously to PWR plants. (orig.)

Power generation and heating performances of integrated system of ammonia–water Kalina–Rankine cycle

International Nuclear Information System (INIS)

Zhang, Zhi; Guo, Zhanwei; Chen, Yaping; Wu, Jiafeng; Hua, Junye

2015-01-01

Highlights: • Integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) is investigated. • Ammonia–water Rankine cycle is operated for cogenerating room heating-water in winter. • Kalina cycle with higher efficiency is operated for power generation in other seasons. • Power recovery efficiency accounts thermal efficiency and waste heat absorbing ratio. • Heating water with 70 °C and capacity of 55% total reclaimed heat load is cogenerated. - Abstract: An integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) for power generation and heating is introduced. The Kalina cycle has large temperature difference during evaporation and small one during condensation therefore with high thermal efficiency for power generation, while the ammonia–water Rankine cycle has large temperature difference during condensation as well as evaporation, thus it can be adopted to generate heating-water as a by-product in winter. The integrated system is based on the Kalina cycle and converted to the Rankine cycle with a set of valves. The performances of the AWKRC system in different seasons with corresponding cycle loops were studied and analyzed. When the temperatures of waste heat and cooling water are 300 °C and 25 °C respectively, the thermal efficiency and power recovery efficiency of Kalina cycle are 20.9% and 17.4% respectively in the non-heating seasons, while these efficiencies of the ammonia–water Rankine cycle are 17.1% and 13.1% respectively with additional 55.3% heating recovery ratio or with comprehensive efficiency 23.7% higher than that of the Kalina cycle in heating season

Integrated design and optimization of technologies for utilizing low grade heat in process industries

International Nuclear Information System (INIS)

Kwak, Dong-Hun; Binns, Michael; Kim, Jin-Kuk

2014-01-01

Highlights: • Implementation of a modeling and design framework for the utilization of low grade heat. • Application of process simulator and optimization techniques for the design of technologies for heat recovery. • Systematic and holistic exploitation for the recovery of industrial low grade heat. • Demonstration of the applicability and benefit of integrated design and optimization framework through a case study. - Abstract: The utilization of low grade heat in process industries has significant potential for improving site-wide energy efficiency. This paper focuses on the techno-economic analysis of key technologies for energy recovery and re-use, namely: Organic Rankine Cycles (ORC), boiler feed water heating, heat pumping and absorption refrigeration in the context of process integration. Process modeling and optimization in a holistic manner identifies the optimal integrated configuration of these technologies, with rigorous assessment of costs and technical feasibility of these technologies. For the systematic screening and evaluation of design options, detailed process simulator models are evaluated and optimization proceeds subject to design constraints for the particular economic scenarios where technology using low grade heat is introduced into the process site. Case studies are presented to illustrate how the proposed modeling and optimization framework can be useful and effective in practice, in terms of providing design guidelines and conceptual insights for the application of technologies using low grade heat. From the case study, the best options during winter are the ORC giving a 6.4% cost reduction for the ideal case with low grade heat available at a fixed temperature and boiler feed water heating giving a 2.5% cost reduction for the realistic case with low grade heat available at a range of temperatures. Similarly during summer boiler feed water heating was found to be the best option giving a 3.1% reduction of costs considering a

77 FR 39735 - Certain Integrated Circuit Packages Provided With Multiple Heat-Conducting Paths and Products...

Science.gov (United States)

2012-07-05

...Notice is hereby given that a complaint was filed with the U.S. International Trade Commission on May 31, 2012, under section 337 of the Tariff Act of 1930, as amended, on behalf of Industrial Technology Research Institute of Taiwan and ITRI International of San Jose, California. The complaint alleges violations of section 337 based upon the importation into the United States, the sale for importation, and the sale within the United States after importation of certain integrated circuit packages provided with multiple heat-conducting paths and products containing same by reason of infringement of certain claims of U.S. Patent No. 5,710,459 (``the `459 patent''). The complaint further alleges that an industry in the United States exists as required by subsection (a)(2) of section 337. The complainants request that the Commission institute an investigation and, after the investigation, issue an exclusion order and cease and desist order.

Thermodynamic analysis and performance assessment of an integrated heat pump system for district heating applications

International Nuclear Information System (INIS)

Soltani, Reza; Dincer, Ibrahim; Rosen, Marc A.

2015-01-01

A Rankine cycle-driven heat pump system is modeled for district heating applications with superheated steam and hot water as products. Energy and exergy analyses are performed, followed by parametric studies to determine the effects of varying operating conditions and environmental parameters on the system performance. The district heating section is observed to be the most inefficient part of system, exhibiting a relative irreversibility of almost 65%, followed by the steam evaporator and the condenser, with relative irreversibilities of about 18% and 9%, respectively. The ambient temperature is observed to have a significant influence on the overall system exergy destruction. As the ambient temperature decreases, the system exergy efficiency increases. The electricity generated can increase the system exergy efficiency at the expense of a high refrigerant mass flow rate, mainly due to the fact that the available heat source is low quality waste heat. For instance, by adding 2 MW of excess electricity on top of the targeted 6 MW of product heat, the refrigerant mass flow rate increases from 12 kg/s (only heat) to 78 kg/s (heat and electricity), while the production of 8 MW of product heat (same total output, but in form of heat) requires a refrigerant mass flow rate of only 16 kg/s. - Highlights: • A new integrated heat pump system is developed for district heating applications. • An analysis and assessment study is undertaken through exergy analysis methodology. • A comparative efficiency evaluation is performed for practical applications. • A parametric study is conducted to investigate how varying operating conditions and state properties affect energy and exergy efficiencies.

Nonlinear thermal convection in a layer of nanofluid under G-jitter and internal heating effects

Directory of Open Access Journals (Sweden)

Bhadauria B. S.

2014-01-01

Full Text Available This paper deals with a mathematical model of controlling heat transfer in nanofluids. The time-periodic vertical vibrations of the system are considered to effect an external control of heat transport along with internal heating effects. A weakly non-linear stability analysis is based on the five-mode Lorenz model using which the Nusselt number is obtained as a function of the thermal Rayleigh number, nano-particle concentration based Rayleigh number, Prandtl number, Lewis number, modified diffusivity ratio, amplitude and frequency of modulation. It is shown that modulation can be effectively used to control convection and thereby heat transport. Further, it is found that the effect of internal Rayleigh number is to enhance the heat and nano-particles transport.

New Integrals Arising in the Samara-Valencia Heat Transfer Model in Grinding

Directory of Open Access Journals (Sweden)

J. L. González-Santander

2017-01-01

Full Text Available The Samara-Valencia model for heat transfer in grinding has been recently used for calculating nontabulated integrals. Based on these results, new infinite integrals can be calculated, involving the Macdonald function and the modified Struve function.

A mixed integer linear programming model for integrating thermodynamic cycles for waste heat exploitation in process sites

International Nuclear Information System (INIS)

Oluleye, Gbemi; Smith, Robin

2016-01-01

Highlights: • MILP model developed for integration of waste heat recovery technologies in process sites. • Five thermodynamic cycles considered for exploitation of industrial waste heat. • Temperature and quantity of multiple waste heat sources considered. • Interactions with the site utility system considered. • Industrial case study presented to illustrate application of the proposed methodology. - Abstract: Thermodynamic cycles such as organic Rankine cycles, absorption chillers, absorption heat pumps, absorption heat transformers, and mechanical heat pumps are able to utilize wasted thermal energy in process sites for the generation of electrical power, chilling and heat at a higher temperature. In this work, a novel systematic framework is presented for optimal integration of these technologies in process sites. The framework is also used to assess the best design approach for integrating waste heat recovery technologies in process sites, i.e. stand-alone integration or a systems-oriented integration. The developed framework allows for: (1) selection of one or more waste heat sources (taking into account the temperatures and thermal energy content), (2) selection of one or more technology options and working fluids, (3) selection of end-uses of recovered energy, (4) exploitation of interactions with the existing site utility system and (5) the potential for heat recovery via heat exchange is also explored. The methodology is applied to an industrial case study. Results indicate a systems-oriented design approach reduces waste heat by 24%; fuel consumption by 54% and CO_2 emissions by 53% with a 2 year payback, and stand-alone design approach reduces waste heat by 12%; fuel consumption by 29% and CO_2 emissions by 20.5% with a 4 year payback. Therefore, benefits from waste heat utilization increase when interactions between the existing site utility system and the waste heat recovery technologies are explored simultaneously. The case study also shows

Residential CO{sub 2} heat pump system for combined space heating and hot water heating

Energy Technology Data Exchange (ETDEWEB)

Stene, Joern

2004-02-01

may result in a considerable increase in the inlet water temperature for the DHW preheating gas cooler. This will in turn reduce the COP of the integrated CO{sub 2} heat pump. The thermodynamic losses are highest at large initial temperature differences for the DHW and the city water, small charging volumes and low gas cooler heating capacities. Inevitable mixing of hot and cold water in the tank will lead to further increase in the thermodynamic losses for the CO{sub 2} heat pump system. (10) One possible way to reduce internal conductive heat transfer and avoid the mixing in cylindrical single-shell DHW storage tanks, is to separate the DHW and the city water by means of a movable plate with low thermal conductivity. The concept proved to give satisfactory thermal performance and functionality at atmospheric operating conditions. However, definite conclusions regarding the functionality, thermal performance and optimum design can only be drawn after full-scale testing has been carried out in a pressurised tank. First-costs as well as the long-term reliability of the insulating plate are also important issues that need to be further addressed.

A combined thermodynamic cycle used for waste heat recovery of internal combustion engine

International Nuclear Information System (INIS)

He, Maogang; Zhang, Xinxin; Zeng, Ke; Gao, Ke

2011-01-01

In this paper, we present a steady-state experiment, energy balance and exergy analysis of exhaust gas in order to improve the recovery of the waste heat of an internal combustion engine (ICE). Considering the different characteristics of the waste heat of exhaust gas, cooling water, and lubricant, a combined thermodynamic cycle for waste heat recovery of ICE is proposed. This combined thermodynamic cycle consists of two cycles: the organic Rankine cycle (ORC), for recovering the waste heat of lubricant and high-temperature exhaust gas, and the Kalina cycle, for recovering the waste heat of low-temperature cooling water. Based on Peng–Robinson (PR) equation of state (EOS), the thermodynamic parameters in the high-temperature ORC were calculated and determined via an in-house computer program. Suitable working fluids used in high-temperature ORC are proposed and the performance of this combined thermodynamic cycle is analyzed. Compared with the traditional cycle configuration, more waste heat can be recovered by the combined cycle introduced in this paper. -- Highlights: ► We study the energy balance of fuel in internal combustion engine. ► Heat recovery effect of exhaust gas is good when ICE is at a high-load condition. ► We propose a new combined thermodynamic cycle for waste heat of ICE. ► The combined cycle has a higher recovery efficiency than previous configurations.

Probabilistic Steady-State Operation and Interaction Analysis of Integrated Electricity, Gas and Heating Systems

Directory of Open Access Journals (Sweden)

Lun Yang

2018-04-01

Full Text Available The existing studies on probabilistic steady-state analysis of integrated energy systems (IES are limited to integrated electricity and gas networks or integrated electricity and heating networks. This paper proposes a probabilistic steady-state analysis of integrated electricity, gas and heating networks (EGH-IES. Four typical operation modes of an EGH-IES are presented at first. The probabilistic energy flow problem of the EGS-IES considering its operation modes and correlated uncertainties in wind/solar power and electricity/gas/heat loads is then formulated and solved by the Monte Carlo method based on Latin hypercube sampling and Nataf transformation. Numerical simulations are conducted on a sample EGH-IES working in the “electricity/gas following heat” mode to verify the probabilistic analysis proposed in this paper and to study the effects of uncertainties and correlations on the operation of the EGH-IES, especially uncertainty transmissions among the subnetworks.

Modeling and analysis of conventional and heat-integrated distillation columns

DEFF Research Database (Denmark)

Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

2015-01-01

A generic model that can cover diabatic and adiabatic distillation column configurations is presented, with the aim ofproviding a consistent basis for comparison of alternative distillation column technologies. Both a static and a dynamic formulation of the model, together with a model catalogue...... consisting of the conventional, the heat-integrated and the mechanical vapor recompression distillation columns are presented. The solution procedure of the model is outlined and illustrated in three case studies. One case study being a benchmark study demonstrating the size of the model and the static...... properties of two different heat-integrated distillation column (HIDiC) schemes and the mechanical vapor recompression column. The second case study exemplifies the difference between a HIDiC and a conventional distillation column in the composition profiles within a multicomponent separation, whereas...

First international workshop on fundamental aspects of post-dryout heat transfer: proceedings

International Nuclear Information System (INIS)

Lee, R.

1984-12-01

The purpose of the First International Workshop on Fundamental Aspects of Post-Dryout Heat Transfer was to review recent developments and the state of art in the field of post-dryout heat transfer. The workshop centered on interchanging ideas, reviewing current research results, and defining future research needs. The following five sessions dealing with the fundamental aspects of post-dryout heat transfer were held. A Computer Code Modeling and Flow Phenomena session was held dealing with flow rgimes, drop size, drop formation and behavior, interfacial area, interfacial drag, and computer modeling. A Quenching Phenomena session was held dealing with nature of rewetting, maximum wetting temperature, Leidenfrost phenomenon and heat transfer in the vicinity of quench front. A Low-Void Heat Transfer session was held dealing with inverted annular-flow heat transfer, inverted slug-flow heat transfer thermal non-equilibrium and computer modeling. A Dispersed-Flow Heat Transfer session was held dealing with drop interfacial heat transfer, vapor convection, thermal non-equilibrium and correlations and models

Characteristics of Vacuum Freeze Drying with Utilization of Internal Cooling and Condenser Waste Heat for Sublimation

Directory of Open Access Journals (Sweden)

Muhammad Alhamid

2013-09-01

Full Text Available Vacuum freeze drying is an excellent drying method, but it is very energy-intensive because a relatively long drying time is required. This research investigates the utilization of condenser waste heat for sublimation as a way of accelerating the drying rate. In addition, it also investigates the effect of internal cooling combined with vacuum cooling in the pressure reduction process. Jelly fish tentacles were used as the specimen, with different configurations for condenser heat waste and internal cooling valve opening. The results show that heating with condenser heat waste can accelerate the drying rate up to 0.0035 kg/m2.s. In addition, pre-freezing by internal cooling prevents evaporation until the mass of the specimen is 0.47 g and promotes transition of the specimen into the solid phase.

International Financial Integration and Economic Growth in India: An Empirical Investigation

Directory of Open Access Journals (Sweden)

Nayia MAHAJAN

2015-11-01

Full Text Available This study endeavors to estimate relationship between international financial integration and economic growth in India during 1981-2011. Apart from direct impact of international financial integration on growth, indirect impact (via financial development has also been studied empirically. Models of co-integration and Vector Error Correction Model (VECM have been applied to examine the relationships. The study observes that international financial integration affects the growth of the economy positively; and change in economic growth due to it through financial development is approximately 8.63 percent. The study also suggests that the structural reforms that took place in India in early nineties did not affect the existing relationship of global financial integration and economic growth significantly.

International Summit on Integrated Environmental Modeling

Science.gov (United States)

This report describes the International Summit on Integrated Environmental Modeling (IEM), held in Washington, DC 7th-9th December 2010. The meeting brought together 57 scientists and managers from leading US and European government and non-governmental organizations, universitie...

Radiant heating tests of several liquid metal heat-pipe sandwich panels

International Nuclear Information System (INIS)

Camarda, C.J.; Basiulis, A.

1983-08-01

Integral heat pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat load levels. The heat pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low distortion large area structures (e.g., space antennas) and laser mirrors

Heat treatment of nuclear reactor pump part in integrated furnace facility

International Nuclear Information System (INIS)

Anon.

1983-01-01

A flexible heat treating system is meeting strict work specifications while accommodating the production flow pattern requirements and floor space needs of Advanced Metal Treating, Inc., Butler, Wis. Modular design and appropriate furnace configurations allow realization of the most efficient heat treat processing and energy use in a relatively small production area. The totally-integrated system (Pacemaker--manufactured by Lindberg, A Unit of General Signal, Chicago) consists of an electric integral-quench furnace with companion draw furnaces, washer unit and a material transfer car. With its one-side, inout configuration, the furnace operates with a minimum of drawing and washing equipment. The integral-quench furnace has a work chamber dimension of 30 by 48 by 30 inches (76.2 x 122 x 76.2 cm). The firm has two of these units, plus three in-out draw furnaces, one washer, one transfer car and two endothermic gas generators

Model of a thermal energy storage device integrated into a solar assisted heat pump system for space heating

International Nuclear Information System (INIS)

Badescu, Viorel

2003-01-01

Details about modelling a sensible heat thermal energy storage (TES) device integrated into a space heating system are given. The two main operating modes are described. Solar air heaters provide thermal energy for driving a vapor compression heat pump. The TES unit ensures a more efficient usage of the collected solar energy. The TES operation is modeled by using two non-linear coupled partial differential equations for the temperature of the storage medium and heat transfer fluid, respectively. Preliminary results show that smaller TES units provide a higher heat flux to the heat pump vaporiser. This makes the small TES unit discharge more rapidly during time periods with higher thermal loads. The larger TES units provide heat during longer time periods, even if the heat flux they supply is generally smaller. The maximum heat flux is extracted from the TES unit during the morning. Both the heat pump COP and exergy efficiency decrease when the TES unit length increases. Also, the monthly thermal energy stored by the TES unit and the monthly energy necessary to drive the heat pump compressor are increased by increasing the TES unit length

Chicken hepatic response to chronic heat stress using integrated transcriptome and metabolome analysis.

Directory of Open Access Journals (Sweden)

Sara F Jastrebski

Full Text Available The liver plays a central role in metabolism and is important in maintaining homeostasis throughout the body. This study integrated transcriptomic and metabolomic data to understand how the liver responds under chronic heat stress. Chickens from a rapidly growing broiler line were heat stressed for 8 hours per day for one week and liver samples were collected at 28 days post hatch. Transcriptome analysis reveals changes in genes responsible for cell cycle regulation, DNA replication, and DNA repair along with immune function. Integrating the metabolome and transcriptome data highlighted multiple pathways affected by heat stress including glucose, amino acid, and lipid metabolism along with glutathione production and beta-oxidation.

International Students' Experiences of Integrating into the Workforce

Science.gov (United States)

Nunes, Sarah; Arthur, Nancy

2013-01-01

This study explored the integration experiences of 16 international students entering the Canadian workforce using a semistructured interview and constant comparison method. The international students were pursuing immigration to Canada, despite unmet job prospects. Students recommended that employers refrain from discriminating against students…

Efficient heat recovery: Integrated circuit systems and heat pipes; Gezielte Waermerueckgewinnung: KV-Systeme und Waermerohr

Energy Technology Data Exchange (ETDEWEB)

Kaup, C. [Howatherm, Bruecken (Germany)

1995-09-18

Integrated circuit systems and heat pipes are both known to be low-efficiency systems, but this shortcoming can be eliminated by constructive measures. (orig.) [Deutsch] Die beiden Verfahren - Kreislaufverbundsystem und das Waermerohr - sind als WRG-Systeme mit geringen Wirkungsgraden bekannt. Doch dieser Nachteil kann durch spezielle Konstruktionsmassnahmen eliminiert werden. (orig.)

Estimation of Surface Temperature and Heat Flux by Inverse Heat Transfer Methods Using Internal Temperatures Measured While Radiantly Heating a Carbon/Carbon Specimen up to 1920 F

Science.gov (United States)

Pizzo, Michelle; Daryabeigi, Kamran; Glass, David

2015-01-01

The ability to solve the heat conduction equation is needed when designing materials to be used on vehicles exposed to extremely high temperatures; e.g. vehicles used for atmospheric entry or hypersonic flight. When using test and flight data, computational methods such as finite difference schemes may be used to solve for both the direct heat conduction problem, i.e., solving between internal temperature measurements, and the inverse heat conduction problem, i.e., using the direct solution to march forward in space to the surface of the material to estimate both surface temperature and heat flux. The completed research first discusses the methods used in developing a computational code to solve both the direct and inverse heat transfer problems using one dimensional, centered, implicit finite volume schemes and one dimensional, centered, explicit space marching techniques. The developed code assumed the boundary conditions to be specified time varying temperatures and also considered temperature dependent thermal properties. The completed research then discusses the results of analyzing temperature data measured while radiantly heating a carbon/carbon specimen up to 1920 F. The temperature was measured using thermocouple (TC) plugs (small carbon/carbon material specimens) with four embedded TC plugs inserted into the larger carbon/carbon specimen. The purpose of analyzing the test data was to estimate the surface heat flux and temperature values from the internal temperature measurements using direct and inverse heat transfer methods, thus aiding in the thermal and structural design and analysis of high temperature vehicles.

Non-equilibrium effects of core-cooling and time-dependent internal heating on mantle flush events

Directory of Open Access Journals (Sweden)

D. A. Yuen

1995-01-01

Full Text Available We have examined the non-equilibrium effects of core-cooling and time-dependent internal-heating on the thermal evolution of the Earth's mantle and on mantle flush events caused by the two major phase transitions. Both two- and three-dimensional models have been employed. The mantle viscosity responds to the secular cooling through changes in the averaged temperature field. A viscosity which decreases algebraically with the average temperature has been considered. The time-dependent internal-heating is prescribed to decrease exponentially with a single decay time. We have studied the thermal histories with initial Rayleigh numbers between 2 x 107 and 108 . Flush events, driven by the non-equilibrium forcings, are much more dramatic than those produced by the equilibrium boundary conditions and constant internal heating. Multiple flush events are found under non-equilibrium conditions in which there is very little internal heating or very fast decay rates of internal-heating. Otherwise, the flush events take place in a relatively continuous fashion. Prior to massive flush events small-scale percolative structures appear in the 3D temperature fields. Time-dependent signatures, such as the surface heat flux, also exhibits high frequency oscillatory patterns prior to massive flush events. These two observations suggest that the flush event may be a self-organized critical phenomenon. The Nusselt number as a function of the time-varying Ra does not follow the Nusselt vs. Rayleigh number power-law relationship based on equilibrium (constant temperature boundary conditions. Instead Nu(t may vary non-monotonically with time because of the mantle flush events. Convective processes in the mantle operate quite differently under non-equilibrium conditions from its behaviour under the usual equilibrium situations.

First and Second-Law Efficiency Analysis and ANN Prediction of a Diesel Cycle with Internal Irreversibility, Variable Specific Heats, Heat Loss, and Friction Considerations

Directory of Open Access Journals (Sweden)

M. M. Rashidi

2014-04-01

Full Text Available The variability of specific heats, internal irreversibility, heat and frictional losses are neglected in air-standard analysis for different internal combustion engine cycles. In this paper, the performance of an air-standard Diesel cycle with considerations of internal irreversibility described by using the compression and expansion efficiencies, variable specific heats, and losses due to heat transfer and friction is investigated by using finite-time thermodynamics. Artificial neural network (ANN is proposed for predicting the thermal efficiency and power output values versus the minimum and the maximum temperatures of the cycle and also the compression ratio. Results show that the first-law efficiency and the output power reach their maximum at a critical compression ratio for specific fixed parameters. The first-law efficiency increases as the heat leakage decreases; however the heat leakage has no direct effect on the output power. The results also show that irreversibilities have depressing effects on the performance of the cycle. Finally, a comparison between the results of the thermodynamic analysis and the ANN prediction shows a maximum difference of 0.181% and 0.194% in estimating the thermal efficiency and the output power. The obtained results in this paper can be useful for evaluating and improving the performance of practical Diesel engines.

Vehicle Exhaust Waste Heat Recovery Model with Integrated Thermal Load Leveling

Science.gov (United States)

2015-08-01

backpressure can decrease engine power by ~1% per inch Hg.27 A specific exhaust heat exchanger design would need to take this effect into account...Materials. 2009;39:2142–2148. 4. Sprouse III C, Depcik C. Review of organic Rankine cycles for internal combustion engine exhaust waste heat recovery...Adams TG. Effect of exhaust system design on engine performance. 1980. SAE Technical Paper No. 800319. 16 1 DEFENSE TECHNICAL

Wind power integration in Aalborg Municipality using compression heat pumps and geothermal absorption heat pumps

DEFF Research Database (Denmark)

Østergaard, Poul Alberg

2013-01-01

-temperature geothermal resources. The analyses have also demonstrated that the municipality will still rely heavily on surrounding areas for electric load balancing assistance. With a departure in a previously elaborated 100% renewable energy scenario, this article investigates how absorption heat pumps (AHP......Aalborg Municipality, Denmark is investigating ways of switching to 100% renewable energy supply over the next 40 years. Analyses so far have demonstrated a potential for such a transition through energy savings, district heating (DH) and the use of locally available biomass, wind power and low......) and compression heat pumps (HP) for the supply of DH impact the integration of wind power. Hourly scenario-analyses made using the EnergyPLAN model reveal a boiler production and electricity excess which is higher with AHPs than with HPs whereas condensing mode power generation is increased by the application...

An international integration history of the Zagreb Stock Exchange

Directory of Open Access Journals (Sweden)

Luka Sikic

2017-06-01

Full Text Available We investigate stock market co-movements among the Croatian and several other markets (in the US, UK, Germany, Austria, Poland, Czech Republic and Hungary in the period from 3 September 1997 to 19 August 2016 with dynamic correlation coefficient models. This allows us to analyse long-term trends of the international financial integration of the Zagreb Stock Exchange in the last two decades as well as the separate impacts of major events that influenced financial markets during that period. Our results imply a relatively low level of international financial integration of the Croatian stock market, but some convergence in co-movement with the analysed markets over time is present. The strongest market co-movement is related to the subprime mortgage crisis, and EU accession seems to have made Croatian international integration less segmented.

Integrated evaluation of radiative heating systems for residential buildings

International Nuclear Information System (INIS)

Anastaselos, Dimitrios; Theodoridou, Ifigeneia; Papadopoulos, Agis M.; Hegger, Manfred

2011-01-01

Based on the need to reduce CO 2 emissions and minimize energy dependency, the EU Member States have set ambitious energy policies goals and have developed respective, specific regulations, in order to improve the energy performance of the building sector. Thus, specific measures regarding the buildings' envelope, the use of efficient HVAC technologies and the integration of renewable energy systems are being constantly studied and promoted. The effective combination of these three main aspects will consequently result in maximum energy efficiency. Germany has played a key role in this development, with intensive work focusing in the improvement of the energy behaviour of the residential building stock. In this paper, the use of radiative heating systems placing special emphasis on infrared is being studied as part of the energy renovation of residential buildings from the 1970's. This is done by applying an integrated assessment model to evaluate specific interventions regarding the improvement of the energy behaviour of the buildings' envelope and the use of radiative heating systems, based on a thorough Life Cycle Analysis according to criteria of energy, economic and environmental performance, as well as thermal comfort. -- Highlights: → Assessment of energy, economic and environmental performance of heating systems. → Life Cycle Analysis in combination with the quality of thermal comfort. → Effectiveness of interventions in already partially insulated buildings.

Integration of a PAFC-Cogeneration Plant into an existing District-Heating-System

International Nuclear Information System (INIS)

Wagner, Ulrich; Geiger, Bernd; Grohmann, Juergen

1999-01-01

The Studiengesellschaft Brennstoffzellen e. V. assigned in the middle of 1995 the Institutions ''Lehrstuhl fir Energiewirtschaft mid Kraftwerkstechnik (IfE)'' to design a concept to integrate an ONSI-PAFC Model C in an existing district heating system. The fuel cell generates about 200 kW electrical and 215 kW thermal power consuming 500 kW natural gas. In the case of complete use of thermal power the fuel cell surpasses the efficiency of conventional systems by about 30 %. The possibilities to install the fuel cell were investigated at three locations, two housing areas, one with 36.000 m2 the other with 60.000 m2 heated area, and one indoor pool. The heating systems are representative of the Federal Republic of Germany. It turned out that the integration of the fuel cell into the existing heating system might be difficult at each location, either the annual consumption of thermal energy was too low or the heating system was operating at a temperature level reducing the usable thermal power of the fuel cell. After further studies the larger housing area was selected, with the intention of using the thermal power of the fuel cell during the whole year and to get high thermal load factors. Some difficulties are caused by the temperature level of the heating system, which is 70/55 o C. (author)

The International Heat Stress Genotype Experiment for modeling wheat response to heat: field experiments and AgMIP-Wheat multi-model simulations

NARCIS (Netherlands)

Martre, P.; Reynolds, M.P.; Asseng, S.; Ewert, F.; Alderman, P.D.; Cammarano, D.; Maiorano, Andrea; Ruane, A.C.; Aggarwal, P.K.; Anothai, J.; Supit, I.; Wolf, J.

2017-01-01

The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown during

Thermophysical fundamentals of cyclonic recirculating heating devices

Science.gov (United States)

Karpov, S. V.; Zagoskin, A. A.

2017-10-01

This report presents the results of experimental and theoretical research of aerodynamics and convective heat transfer in cyclone devices with the new system of external recirculation of heating gas under the influence of radial pressure gradient in a heat carrier’s swirling turbulent flow. The dynamic problem of tangential velocity distribution in a clearance volume is solved at various re-circulation ratio values including limiting quantities (kr = 0; 1) and variations in cyclonic combustion chamber’s design parameters and operating conditions (Rer); the integrated calculation ratios for fundamental aerodynamic characteristics of a recirculation device are derived. The first experimental and numerical studies of convective heat transfer on internal and external surfaces of a hollow shaft in a swirling recirculation flow are derived through the instrumentality of OpenFOAM, these studies are also conducted for a setting of several cylindrical solid inserts. The external surface heat problem of a hollow cylindrical insert is solved with integral and digital methods; generalized similarity equations for the internal and external surfaces extended in range of Reynolds number are derived. The experimental data is in reasonable agreement with the derived curves and the results of mathematic modelling of convective heat transfer. Calculation recommendations for optimal selection of kr values at various ratios of their geometric characteristics and products utilization rate are obtained.

Biomass pyrolysis and combustion integral and differential reaction heats with temperatures using thermogravimetric analysis/differential scanning calorimetry.

Science.gov (United States)

Shen, Jiacheng; Igathinathane, C; Yu, Manlu; Pothula, Anand Kumar

2015-06-01

Integral reaction heats of switchgrass, big bluestem, and corn stalks were determined using thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Iso-conversion differential reaction heats using TGA/DSC pyrolysis and combustion of biomass were not available, despite reports available on heats required and released. A concept of iso-conversion differential reaction heats was used to determine the differential reaction heats of each thermal characteristics segment of these materials. Results showed that the integral reaction heats were endothermic from 30 to 700°C for pyrolysis of switchgrass and big bluestem, but they were exothermic for corn stalks prior to 587°C. However, the integral reaction heats for combustion of the materials followed an endothermic to exothermic transition. The differential reaction heats of switchgrass pyrolysis were predominantly endothermic in the fraction of mass loss (0.0536-0.975), and were exothermic for corn stalks (0.0885-0.850) and big bluestem (0.736-0.919). Study results provided better insight into biomass thermal mechanism. Published by Elsevier Ltd.

Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

DEFF Research Database (Denmark)

Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

2014-01-01

production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible...... district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the expected operation pattern of such polygeneration system is taken......Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol...

Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics.

Science.gov (United States)

Surducan, E; Surducan, V; Limare, A; Neamtu, C; Di Giuseppe, E

2014-12-01

We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm(3) convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

Experimental study of humidity distribution inside electronic enclosure and effect of internal heating

DEFF Research Database (Denmark)

Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

2016-01-01

on the humidity and temperature profile inside typical electronic enclosures. Defined parameters include external temperature and humidity conditions, temperature and time of the internal heat cycle, thermal mass, and ports/openings size. The effect of the internal humidity on electronic reliability has been......Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in a wide range of temperature and humidity during day and night time periods. Corrosion failures are still a challenge due to the combined effects...... of temperature, humidity and corrosion accelerating species in the atmosphere. Moreover the surface region of printed circuit board assemblies is often contaminated by various aggressive chemical species.This study describes the overall effect of the exposure to severe climate conditions and internal heat cycles...

Integration of the time-dependent heat equation in the fuel rod performance program IAMBUS

International Nuclear Information System (INIS)

West, G.

1982-01-01

An iterative numerical method for integration of the time-dependent heat equation is described. No presuppositions are made for the dependency of the thermal conductivity and heat capacity on space, time and temperature. (orig.) [de

Propagation of internal stresses in composite materials during heating and cooling according to thermal cycles of welding

International Nuclear Information System (INIS)

Gukasyan, L.E.; Belov, V.V.

1977-01-01

Investigations of free thermal expansion of a composite material, of fibre and matrix during welding thermal cycle make it possible to estimate mean internal strain and stress in the composite components, as well as the residual internal stress and strain present in the composite material after manufacturing. The samples investigated consisted of nickel-chromium EhI445 alloy, reinforced by tungsten-rhenium alloy fibres. As the composite material was cooled and heated in course of welding, the stress and strain changed their sign twice, the first time upon heating, the second time upon cooling. After complete cooling of the composite material residual stresses in the fibre stay at the proportionality level, while those in the matrix are lower. Experimental evidence of internal stress and strain appearing in the composite material during heating are fairly consistent with calculations in the elastic region, if account is taken of the temperature of internal residual stress relaxation upon heating

Main results of assessing integrity of RNPP-3 steam generator heat exchange tubes in accident management

International Nuclear Information System (INIS)

Shugajlo, Al-j P.; Mustafin, M.A.; Shugajlo, Al-r P.; Ryzhov, D.I.; Zhabin, O.I.

2017-01-01

Tubes integrity evaluation under accident conditions considering drain of SG and current technical state of steam exchange tubes is an important question regarding SG long-term operation and improvement of accident management strategy.The main investigation results prepared for heat exchange surface of RNPP-3 steam generator are presented in this research aimed at assessing integrity of heat exchange tubes under accident conditions, which lead to full or partial drain of heat exchange surface, in particular during station blackout.

Some Problems of the Integration of Heat Pump Technology into a System of Combined Heat and Electricity Production

Directory of Open Access Journals (Sweden)

G. Böszörményi

2001-01-01

Full Text Available The closure of a part of the municipal combined heat and power (CHP plant of Košice city would result in the loss of 200 MW thermal output within a realtively short period of time. The long term development plan for the Košice district heating system concentrates on solving this problem. Taking into account the extremely high (90 % dependence of Slovakia on imported energy sources and the desirability of reducing the emission of pollutantst the alternative of supplying of 100 MW thermal output from geothermal sources is attractive. However the indices of economic efficiency for this alternative are unsatisfactory. Cogeneration of electricity and heat in a CHP plant, the most efficient way of supplying heat to Košice at the present time. If as planned, geothermal heat is fed directly into the district heating network the efficiency would be greatly reduced. An excellent solution of this problem would be a new conception, preferring the utilization of geothermal heat in support of a combined electricity and heat production process. The efficiency of geothermal energy utilization could be increased through a special heat pump. This paper deals with several aspects of the design of a heat pump to be integrated into the system of the CHP plant.

Evaluation of opportunities for heat integration of biomass-based Fischer–Tropsch crude production at Scandinavian kraft pulp and paper mill sites

International Nuclear Information System (INIS)

Ljungstedt, Hanna; Pettersson, Karin; Harvey, Simon

2013-01-01

This study investigates heat integrated production of FT (Fischer–Tropsch) crude, where excess heat from the FT crude plant is delivered to a typical Scandinavian pulp and paper mill that produces fine paper. The sizes of FT crude plants are quantified, when the amount of excess heat from the FT plant exactly matches the heating demand otherwise satisfied by the bark boiler at the mill, considering a number of development pathways at the mill, including various degrees of steam savings and biorefinery options, such as lignin extraction. Performance of integrated production is compared with that of an FT stand-alone plant on the basis of wood fuel-to-FT crude efficiency, GHG (greenhouse gas) emissions balances and FT crude production cost. The results show that there exists a heat integration opportunity for an FT crude plant ranging from 0 up to 350 MW (LHV) of wood fuel depending on the development pathway for the mill. The results indicate higher overall efficiency and a generally lower production cost for the heat integrated, co-located production. Heat integrated production has a larger potential to contribute to GHG emission mitigation, assuming a future generation of grid electricity emitting equal to or less than an NGCC (natural gas combined cycle) power plant. - Highlights: • We investigate opportunities for heat integrated FT crude production at a mill. • Typical kraft pulp and paper mills have a potential for heat integrated production. • We compare the heat integrated production with stand-alone FT crude production. • Higher efficiency and lower production cost for heat integrated production. • Reduction of GHG emissions is strongly dependent on grid electricity emissions

A Modeling Framework for Conventional and Heat Integrated Distillation Columns

DEFF Research Database (Denmark)

Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

2013-01-01

In this paper, a generic, modular model framework for describing fluid separation by distillation is presented. At present, the framework is able to describe a conventional distillation column and a heat-integrated distillation column, but due to a modular structure the database can be further...

On oscillatory magnetoconvection in a nanofluid layer in the presence of internal heat source and Soret effect

Science.gov (United States)

Khalid, Izzati Khalidah; Mokhtar, Nor Fadzillah Mohd; Bakri, Nur Amirah; Siri, Zailan; Ibrahim, Zarina Bibi; Gani, Siti Salwa Abd

2017-11-01

The onset of oscillatory magnetoconvection for an infinite horizontal nanofluid layer subjected to Soret effect and internal heat source heated from below is examined theoretically with the implementation of linear stability theory. Two important properties that are thermophoresis and Brownian motion are included in the model and three types of lower-upper bounding systems of the model: rigid-rigid, rigid-free as well as free-free boundaries are examined. Eigenvalue equations are gained from a normal mode analysis and executed using Galerkin technique. Magnetic field effect, internal heat source effect, Soret effect and other nanofluid parameters on the oscillatory convection are presented graphically. For oscillatory mode, it is found that the effect of internal heat source is quite significant for small values of the non-dimensional parameter and elevating the internal heat source speed up the onset of convection. Meanwhile, the increasing of the strength of magnetic field in a nanofluid layer reduced the rate of thermal instability and sustain the stabilization of the system. For the Soret effect, the onset of convection in the system is accelerated when the values of the Soret effect is increased.

Coupled heat conduction and thermal stress formulation using explicit integration

International Nuclear Information System (INIS)

Marchertas, A.H.; Kulak, R.F.

1982-06-01

The formulation needed for the conductance of heat by means of explicit integration is presented. The implementation of these expressions into a transient structural code, which is also based on explicit temporal integration, is described. Comparisons of theoretical results with code predictions are given both for one-dimensional and two-dimensional problems. The coupled thermal and structural solution of a concrete crucible, when subjected to a sudden temperature increase, shows the history of cracking. The extent of cracking is compared with experimental data

Development of an integral computer code for simulation of heat exchangers

International Nuclear Information System (INIS)

Horvat, A.; Catton, I.

2001-01-01

Heat exchangers are one of the basic installations in power and process industries. The present guidelines provide an ad-hoc solution to certain design problems. A unified approach based on simultaneous modeling of thermal-hydraulics and structural behavior does not exist. The present paper describes the development of integral numerical code for simulation of heat exchangers. The code is based on Volume Averaging Technique (VAT) for porous media flow modeling. The calculated values of the whole-section drag and heat transfer coefficients show an excellent agreement with already published values. The matching results prove the correctness of the selected approach and verify the developed numerical code used for this calculation.(author)

Design and evaluation of heat utilization systems for the HTTR through international cooperation

Energy Technology Data Exchange (ETDEWEB)

Lewkowicz, I. [International Atomic Energy Agency, Vienna (Austria)

1996-07-01

The International Atomic Energy Agency (IAEA) has the statutory function to `foster the exchange of scientific and technical information`, and `encourage and assist research on, and development and practical application of, atomic energy for peaceful uses throughout the world`. The IAEA Co-ordinated Research Programmes (CRPs) are effective vehicles for implementing the above. The CRP on Design and Evaluation of Heat Utilization Systems for HTTR has started in September 1994 and is aimed at promoting international co-operation to identify the most promising heat utilization system(s) to be demonstrated at the HTTR, for the benefit of current operators and future designers and constructors of HTGRs. Participating Member States are collaborating by exchanging existing technical information on the technology of heat utilization systems, by developing design concepts and by performing evaluations of candidate systems for potential demonstration with the HTTR. In this report, the systems are reviewed. (J.P.N.)

Design and evaluation of heat utilization systems for the HTTR through international cooperation

International Nuclear Information System (INIS)

Lewkowicz, I.

1996-01-01

The International Atomic Energy Agency (IAEA) has the statutory function to 'foster the exchange of scientific and technical information', and 'encourage and assist research on, and development and practical application of, atomic energy for peaceful uses throughout the world'. The IAEA Co-ordinated Research Programmes (CRPs) are effective vehicles for implementing the above. The CRP on Design and Evaluation of Heat Utilization Systems for HTTR has started in September 1994 and is aimed at promoting international co-operation to identify the most promising heat utilization system(s) to be demonstrated at the HTTR, for the benefit of current operators and future designers and constructors of HTGRs. Participating Member States are collaborating by exchanging existing technical information on the technology of heat utilization systems, by developing design concepts and by performing evaluations of candidate systems for potential demonstration with the HTTR. In this report, the systems are reviewed. (J.P.N.)

Finite element simulation of internal flows with heat transfer using a ...

Indian Academy of Sciences (India)

Unknown

Velocity correction method; finite element simulation; turbulent .... CFD, developments in turbulence modeling have been only evolutionary and ...... variables are made dimensionless using appropriate combinations of Uav, H, ...... Srinivas M 1994 Finite element analysis of internal flows with heat transfer Ph D thesis, Indian.

Laboratory Performance Evaluation of Residential Integrated Heat Pump Water Heaters

Energy Technology Data Exchange (ETDEWEB)

Sparn, B.; Hudon, K.; Christensen, D.

2014-06-01

This paper explores the laboratory performance of five integrated Heat Pump Water Heaters (HPWHs) across a wide range of operating conditions representative of U.S. climate regions. HPWHs are expected to provide significant energy savings in certain climate zones when compared to typical electric resistance water heaters. Results show that this technology is a viable option in most climates, but differences in control schemes and design features impact the performance of the units tested. Tests were conducted to map heat pump performance across the operating range and to determine the logic used to control the heat pump and the backup electric heaters. Other tests performed include two unique draw profile tests, reduced air flow performance tests and the standard DOE rating tests. The results from all these tests are presented here for all five units tested. The results of these tests will be used to improve the EnergyPlus heat pump water heater for use in BEopt™ whole-house building simulations.

Laboratory Performance Evaluation of Residential Integrated Heat Pump Water Heaters

Energy Technology Data Exchange (ETDEWEB)

Sparn, B.; Hudon, K.; Christensen, D.

2014-06-01

This paper explores the laboratory performance of five integrated Heat Pump Water Heaters (HPWHs) across a wide range of operating conditions representative of US climate regions. HPWHs are expected to provide significant energy savings in certain climate zones when compared to typical electric resistance water heaters. Results show that this technology is a viable option in most climates, but differences in control schemes and design features impact the performance of the units tested. Tests were conducted to map heat pump performance across the operating range and to determine the logic used to control the heat pump and the backup electric heaters. Other tests performed include two unique draw profile tests, reduced air flow performance tests and the standard DOE rating tests. The results from all these tests are presented here for all five units tested. The results of these tests will be used to improve the EnergyPlus heat pump water heater for use in BEopt(tm) whole-house building simulations.

Detailed comparison between decay heat data calculated by the summation method and integral measurements

International Nuclear Information System (INIS)

Rudstam, G.

1979-01-01

The fission product library FPLIB has been used for a calculation of the decay heat effect in nuclear fuel. The results are compared with integral determinations and with results obtained using the ENDF/BIV data base. In the case of the beta part, and also for the total decay heat, the FPLIB-data seem to be superior to the ENDF/BIV-data. The experimental integral data are in many cases reproduced within the combined limits of error of the methods. (author)

Investigation of forced convection heat transfer of supercritical pressure water in a vertically upward internally ribbed tube

International Nuclear Information System (INIS)

Wang Jianguo; Li Huixiong; Guo Bin; Yu Shuiqing; Zhang Yuqian; Chen Tingkuan

2009-01-01

In the present paper, the forced convection heat transfer characteristics of water in a vertically upward internally ribbed tube at supercritical pressures were investigated experimentally. The six-head internally ribbed tube is made of SA-213T12 steel with an outer diameter of 31.8 mm and a wall thickness of 6 mm and the mean inside diameter of the tube is measured to be 17.6 mm. The experimental parameters were as follows. The pressure at the inlet of the test section varied from 25.0 to 29.0 MPa, and the mass flux was from 800 to 1200 kg/(m 2 s), and the inside wall heat flux ranged from 260 to 660 kW/m 2 . According to experimental data, the effects of heat flux and pressure on heat transfer of supercritical pressure water in the vertically upward internally ribbed tube were analyzed, and the characteristics and mechanisms of heat transfer enhancement, and also that of heat transfer deterioration, were also discussed in the so-called large specific heat region. The drastic changes in thermophysical properties near the pseudocritical points, especially the sudden rise in the specific heat of water at supercritical pressures, may result in the occurrence of the heat transfer enhancement, while the covering of the heat transfer surface by fluids lighter and hotter than the bulk fluid makes the heat transfer deteriorated eventually and explains how this lighter fluid layer forms. It was found that the heat transfer characteristics of water at supercritical pressures were greatly different from the single-phase convection heat transfer at subcritical pressures. There are three heat transfer modes of water at supercritical pressures: (1) normal heat transfer, (2) deteriorated heat transfer with low HTC but high wall temperatures in comparison to the normal heat transfer, and (3) enhanced heat transfer with high HTC and low wall temperatures in comparison to the normal heat transfer. It was also found that the heat transfer deterioration at supercritical pressures was

Environmental and Economic Benefit Analysis of an Integrated Heating System with Geothermal Energy—A Case Study in Xi’an China

Directory of Open Access Journals (Sweden)

Qingyou Yan

2017-12-01

Full Text Available Due to the increase in environmental problems and air pollution during the heating period, it is important to promote clean heating in cold regions, thereby meeting the heating demand in a green manner. In order to allocate resources more effectively and facilitate the consumption of renewable energy, this paper designs an integrated heating system that incorporates geothermal energy into the framework of an integrated energy system of electricity, heating, and gas. An analysis of the environmental and economic benefits indicates that the system reduces pollutant emissions and decreases the cost of urban heating. Using an example of central heating of residential buildings in Xi’an, the paper conducts a scenario analysis based on the gas peak-shaving ratio and the ratio of geothermal heating loads to basic heating loads. The results demonstrate that the environmental and economic benefits of the integrated heating system are higher compared to central heating using coal-fired boilers. In addition, this paper conducts a sensitivity analysis of the heat source to the price factors and the load ratios. The results show that the operating costs of the integrated heating system are most sensitive to the natural gas price and the gas peak-shaving ratio. Therefore, an optimum natural gas peak-shaving ratio can be determined.

Integration of a magnetocaloric heat pump in a low-energy residential building

DEFF Research Database (Denmark)

Johra, Hicham

2018-01-01

The EnovHeat project aims at developing an innovative heat pump system based on the magnetocaloric effect and active magnetic regenerator technology to provide for the heating needs of a single family house in Denmark. Unlike vapor-compression devices, magnetocaloric heat pumps use the reversible...... heat pump can deliver 2600 W of heating power with an appreciable average seasonal system COP of 3.93. On variable part-load operation with a simple fluid flow controller, it can heat up an entire house with an average seasonal system COP of 1.84....... magnetocaloric effect of a solid refrigerant to build a cooling/heating cycle. It has the potential for high coefficient of performance, more silent operation and efficient part-load control. After presenting the operation principles of the magnetocaloric device and the different models used in the current...... numerical study, this article demonstrates for the first time the possibility to utilize this novel heat pump in a building. This device can be integrated in a single hydronic loop including a ground source heat exchanger and a radiant under-floor heating system. At maximum capacity, this magnetocaloric...

Simulation and uncertainties of the heat transfer from a heat-generating DEBRIS bed in the lower plenum

International Nuclear Information System (INIS)

Schaaf, K.; Trambauer, K.

1999-01-01

The findings of the TMI-2 post-accident analyses indicated that internal cooling mechanisms may have a considerable potential to sustain the vessel integrity after a relocation of core material to the lower plenum, provided that water is continuously available in the RPV. Numerous analytical and experimental research activities are currently underway in this respect. This paper illustrates some major findings of the experimental work on internal cooling mechanisms and describes the limitations and the uncertainties in the simulation of the heat transfer processes. Reference is made especially to the joint German DEBRIS/ RPV research program, which encompasses the experimental investigation of the thermal-hydraulics in gaps, of the heat transfer within a particulate debris bed, and of the high temperature performance of vessel steel, as well as the development of simulation models for the heat transfer in the lower head and the structural response of the RPV. In particular, the results of uncertainty and sensitivity analyses are presented, which have been carried out at GRS using an integral model that describes the major phenomena governing the long-term integrity of the reactor vessel. The investigation of a large-scale relocation indicated that the verification of a gap cooling mechanism as an inherent mechanism is questionable in terms of a stringent probabilistic uncertainty criterion, as long as the formation of a large molten pool cannot be excluded. (author)

Mixed convection stagnation-point flow of nanofluids over a stretching/shrinking sheet in a porous medium with internal heat generation/absorption

Directory of Open Access Journals (Sweden)

Dulal Pal

2015-05-01

Full Text Available In this paper, we analyzed the buoyancy-driven radiative non-isothermal heat transfer in a nanofluid stagnation-point flow over a stretching/shrinking sheet embedded in a porous medium.The effects of thermal radiation and internal heat generation/absorption along with suction/injection at the boundary are also considered. Three different types of nanofluids, namely the Copper-water, the Alumina-water and the Titanium dioxide water are considered. The resulting coupled nonlinear differential equations are solved numerically by a fifth-order Runge-Kutta-Fehlberg integration scheme with a shooting technique. A good agreement is found between the present numerical results and the available results in the literature for some special cases. The effects of the physical parameters on the flow and temperature characteristics are presented through tables and graphs, and the salient features are discussed. The results obtained reveal many interesting behaviors that warrant further study on the heat transfer enhancement due to the nanofluids.

Supervisory Model Predictive Control of the Heat Integrated Distillation Column

DEFF Research Database (Denmark)

Meyer, Kristian; Bisgaard, Thomas; Huusom, Jakob Kjøbsted

2017-01-01

This paper benchmarks a centralized control system based on model predictive control for the operation of the heat integrated distillation column (HIDiC) against a fully decentralized control system using the most complete column model currently available in the literature. The centralized control...... system outperforms the decentralized system, because it handles the interactions in the HIDiC process better. The integral absolute error (IAE) is reduced by a factor of 2 and a factor of 4 for control of the top and bottoms compositions, respectively....

Performance of an effectively integrated biomass multi-stage gasification system and a steel industry heat treatment furnace

International Nuclear Information System (INIS)

Gunarathne, Duleeka Sandamali; Mellin, Pelle; Yang, Weihong; Pettersson, Magnus; Ljunggren, Rolf

2016-01-01

Highlights: • Multi-stage biomass gasification is integrated with steel heat treatment furnace. • Fossil fuel derived CO_2 emission is eliminated by replacing natural gas with syngas. • The integrated system uses waste heat from the furnace for biomass gasification. • Up to 13% increment of the gasifier system energy efficiency is observed. • Fuel switching results in 10% lower flue gas loss and improved furnace efficiency. - Abstract: The challenges of replacing fossil fuel with renewable energy in steel industry furnaces include not only reducing CO_2 emissions but also increasing the system energy efficiency. In this work, a multi-stage gasification system is chosen for the integration with a heat treatment furnace in the steel powder industry to recover different rank/temperature waste heat back to the biomass gasification system, resulting higher system energy efficiency. A system model based on Aspen Plus was developed for the proposed integrated system considering all steps, including biomass drying, pyrolysis, gasification and the combustion of syngas in the furnace. Both low temperature (up to 400 °C) and high temperature (up to 700 °C) heat recovery possibilities were analysed in terms of energy efficiency by optimizing the biomass pretreatment temperature. The required process conditions of the furnace can be achieved by using syngas. No major changes to the furnace, combustion technology or flue gas handling system are necessary for this fuel switching. Only a slight revamp of the burner system and a new waste heat recovery system from the flue gases are required. Both the furnace efficiency and gasifier system efficiency are improved by integration with the waste heat recovery. The heat recovery from the hot furnace flue gas for biomass drying and steam superheating is the most promising option from an energy efficiency point of view. This option recovers two thirds of the available waste heat, according to the pinch analysis performed

Influence of individual heat pumps on wind power integration – Energy system investments and operation

International Nuclear Information System (INIS)

Hedegaard, Karsten; Münster, Marie

2013-01-01

Highlights: • Individual heat pumps can significantly support the integration of wind power. • The heat pumps significantly reduce fuel consumption, CO 2 emissions, and costs. • Heat storages for the heat pumps can provide only moderate system benefits. • Main benefit of flexible heat pump operation is a lower peak/reserve capacity need. • Socio-economic feasibility only identified for some heat storages to some extent. - Abstract: Individual heat pumps are expected to constitute a significant electricity demand in future energy systems. This demand becomes flexible if investing in complementing heat storage capabilities. In this study, we analyse how the heat pumps can influence the integration of wind power by applying an energy system model that optimises both investments and operation, and covers various heat storage options. The Danish energy system by 2030 with around 50–60% wind power is used as a case study. Results show that the heat pumps, even without flexible operation, can contribute significantly to facilitating larger wind power investments and reducing system costs, fuel consumption, and CO 2 emissions. Investments in heat storages can provide only moderate system benefits in these respects. The main benefit of the flexible heat pump operation is a reduced need for peak/reserve capacity, which is also crucial for the feasibility of the heat storages. Socio-economic feasibility is identified for control equipment enabling intelligent heat storage in the building structure and in existing hot water tanks. In contrast, investments in new heat accumulation tanks are not found competitive

Industrial implementation issues of Total Site Heat Integration

International Nuclear Information System (INIS)

Chew, Kew Hong; Klemeš, Jiří Jaromír; Wan Alwi, Sharifah Rafidah; Abdul Manan, Zainuddin

2013-01-01

Heat Integration has been a well-established energy conservation strategy in the industry. Total Site Heat Integration (TSHI) has received growing interest since its inception in the 90s. The methodology has been used with certain simplifications to solve TSHI problems. This paper investigates the main issues that can influence the practical implementation of TSHI in the industry. The main aim is to provide an assessment and possible guidance for future development and extension of the TSHI methodology from the industrial perspective. Several key issues have been identified as being of vital importance for the industries: design, operation, reliability/availability/maintenance, regulatory/policy and economics. Design issues to consider include plant layout, pressure drop, etc. For operation, issues such as startup and shutdown need to be considered. Reliability, availability and maintenance (RAM) are important as they directly affect the production. Relevant government policy and incentives are also important when considering the options for TSHI. Finally, a TSHI system needs to be economically viable. This paper highlights the key issues to be considered for a successful implementation of TSHI. The impacts of these issues on TS integration are summarised in a matrix, which forms a basis for an improved and closer-to-real-life implementation of the TSHI methodology. Highlights: ► Current TSHI methodology has been used for solving models with certain simplifications. ► Several issues that can influence practical implementation of TSHI are identified. ► Impacts of these issues on safety, environment and economics are evaluated. ► The findings form a basis for an improved and practical implementation of TSHI

Study on boiling heat transfer from diode elements in an integrated circuit chip

Energy Technology Data Exchange (ETDEWEB)

Hijikata, Kunio; Nagasaki, Takao; Kurata, Naoki (Tokyo Institute of Technology Faculty of Engineering (Japan))

1989-02-25

By temperature measurement of elements in boiling experiments with diodes in an integrated circuit (IC) chip, characteristics of boiling heat transfer from tiny heat generating elements in an IC chip and thermal transfer characteristics of multiple heating elements adjoining positioned were studied. The Package of an IC was removed by acid to expose the IC chip. Electricity is applied to the diode in the IC to study the heat transfer properties. The heat transfer rate from a tiny heating element on an IC is greater than that from the conventional continual heated surface. In the case of heat generation by two adjoining elements, the relationship between the total amount of heat and the temperature of elements shows the same characteristics as in the case with a single element. The boiling heat transfer properties of an element in an IC chip are influenced by such microstructure surrounding the element as the pattern of wiring. Heat transfer increases with the decreasing size of the heating element by the heat transfer to the substrate beneath the element. 10 refs., 15 figs.

Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

Energy Technology Data Exchange (ETDEWEB)

Xiaoyan, Zhang [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China)], E-mail: gqzxy@sohu.com; Xingqun, Zhang; Yunguang, Chen; Xiuling, Yuan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

2008-06-15

The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes.

Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoyan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); Zhang, Xingqun; Chen, Yunguang; Yuan, Xiuling [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

2008-06-15

The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5{sup o}C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes. (author)

Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

International Nuclear Information System (INIS)

Zhang Xiaoyan; Zhang Xingqun; Chen Yunguang; Yuan Xiuling

2008-01-01

The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m -2 s -1 , heat flux from 11 to 32 kW m -2 , evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes

Directions of Development of International Production Specialization Theory in Terms of Integration

Directory of Open Access Journals (Sweden)

Lidiya Aleksandrovna Pankova

2016-06-01

Full Text Available The article is devoted to the definition of directions of development of the theory of international production specialization in terms of integration based on new trends in various areas of international business. The author proposes a new concept of international industrial specialization in terms of integration. As a result of research the author came to the conclusion that in the current economic conditions the need for a free market constraints associated with the deepening global market failures is becoming more and more obvious. Therefore, in the process of international specialization of production in the conditions of integration of the country should be guided not by comparative advantage in the production of certain goods or services, but also by other criteria. These criteria are: financial criterion determining the financial situation in the country, the trade criterion, reflecting the possibility of benefiting from international trade, technological criterion, considering the technological security of the country in the field of specialization and the cyclical criterion, reflecting the situation in the world economy and the level of integration of the country. On the basis of these criteria, the author identifies three categories of countries according to their ability to benefit from an international industrial specialization in the integration process: effective export, export-neutral and export-inefficient countries.

Fuel-efficiency of hydrogen and heat storage technologies for integration of fluctuating renewable energy sources

DEFF Research Database (Denmark)

Mathiesen, Brian Vad; Lund, Henrik

2005-01-01

This paper presents the methodology and results of analysing the use of different energy storage technologies in the task of integration of fluctuating renewable energy sources (RES) into the electricity supply. The analysis is done on the complete electricity system including renewable energy...... sources as well as power plants and CHP (Combined heat and power production). Emphasis is put on the need for ancillary services. Devices to store electricity as well as devices to store heat can be used to help the integration of fluctuating sources. Electricity storage technologies can be used...... to relocate electricity production directly from the sources, while heat storage devices can be used to relocate the electricity production from CHP plants and hereby improve the ability to integrate RES. The analyses are done by advanced computer modelling and the results are given as diagrams showing...

Annual performance of building-integrated photovoltaic/water-heating system for warm climate application

International Nuclear Information System (INIS)

Chow, T.T.; Chan, A.L.S.; Fong, K.F.; Lin, Z.; He, W.; Ji, J.

2009-01-01

A building-integrated photovoltaic/water-heating (BiPVW) system is able to generate higher energy output per unit collector area than the conventional solar systems. Through computer simulation with energy models developed for this integrative solar system in Hong Kong, the results showed that the photovoltaic/water-heating (PVW) system has economic advantages over the conventional photovoltaic (PV) installation. The system thermal performance under natural water circulation was found better than the pump-circulation mode. For a specific BiPVW system at a vertical wall of a fully air-conditioned building and with collectors equipped with flat-box-type thermal absorber and polycrystalline silicon cells, the year-round thermal and cell conversion efficiencies were found respectively 37.5% and 9.39% under typical Hong Kong weather conditions. The overall heat transmission through the PVW wall is reduced to 38% of the normal building facade. When serving as a water pre-heating system, the economical payback period was estimated around 14 years. This greatly enhances the PV market opportunities. (author)

Integrated solar-assisted heat pumps for water heating coupled to gas burners; control criteria for dynamic operation

International Nuclear Information System (INIS)

Scarpa, F.; Tagliafico, L.A.; Tagliafico, G.

2011-01-01

A direct expansion integrated solar-assisted heat pump (ISAHP) is compared to a traditional flat plate solar panel for low temperature (45 deg. C) water heating applications. The (simulated) comparison is accomplished assuming both the devices are energy supplemented with an auxiliary standard gas burner, to provide the typical heat duty of a four-member family. Literature dynamical models of the systems involved have been used to calculate the main performance figures in a context of actual climatic conditions and typical stochastic user demand. The paper highlights new heat pump control concepts, needed when maximum energy savings are the main goal of the apparatus for given user demand. Simulations confirm the high collector efficiency of the ISAHP when its panel/evaporator works at temperature close to the ambient one. The device, with respect to a flat plate solar water heater, shows a doubled performance, so that it can do the same task just using an unglazed panel with roughly half of the surface.

A new methodology for greenhouse gas reduction in industry through improved heat exchanging and/or integration of combined heat and power

International Nuclear Information System (INIS)

Axelsson, H.; Asblad, A.; Berntsson, T.

1999-01-01

This paper presents a method that identifies economically optimal combinations of enhanced heat recovery, integration of combined heat and power (CHP), and fuel switching, in an existing industrial energy system at various emission levels. Novel types of composite curves based on pinch technology, representing the existing temperature levels for supplying heat and the possible ones that may be attained after retrofitting, are used as tools for estimating the opportunities for CHP and the trade-off between improved heat exchanging and CHP. The method is explained by an example. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Process Integration Study of Cache Valley Cheese Plant [Advanced Industrial Heat Pump Applications and Evaluations

Energy Technology Data Exchange (ETDEWEB)

Eastwood, A.

1991-10-01

This work has carried out in two phases: Phase 1; identification of opportunities for heat pumps in industrial applications and Phase 2; evaluation of heat pumps in industrial applications. In Phase 1, pinch analysis was applied to several industrial sites to identify the best opportunities for heat pumping and other forms of heat integration. In Phase 2, more detailed analyses were undertaken, including the evaluation of a heat pump installed as a recommendation of Phase 1.

The design of integrated cooling processes in district heating systems; Kylprocessers design i fjaerrvaermesystem

Energy Technology Data Exchange (ETDEWEB)

Martin, Viktoria [Royal Inst. of Technology, Stockholm (SE). Dept. of Chemical Engineering and Technology; Setterwall, Fredrik [Fredrik Setterwall Konsult AB, Sollentuna (Sweden); Andersson, Mikael [AB Berglunds Rostfria, Boden (Sweden)

2005-07-01

This report presents the results from an investigation regarding the design of integrated cooling processes in district heating systems. Increasing investment levels in district heating networks combined with expanding comfort cooling demand makes heat-driven cooling processes extremely interesting. This solution has a great potential tbe cost effective. At the same time, the problem with the environmentally harmful refrigerants used in conventional vapor compression chillers is avoided. In many cases it is beneficial for the district heating provider to lower the supply and/or return temperatures in the network, at least for part of the year. In combined heat and power generation (CHP) a lower supply temperature means that the electricity yield increases. In this context, it is important to consider that conventional absorption chillers are designed to run on 120 deg C heat. However,they can work on heat with temperature as low as 80 deg C if a chiller with a large enough generator area is used, although this has a negative impact on the dimensions of other components and leads ta lower coefficient of performance. For these reasons low temperature driven absorption chillers have been developed in recent years. Two concepts (from different manufacturers) are now available on the market. Factors that affect the choice of district heat-integrated cooling processes have been investigated in this study. Key system aspects that embody a holistic view on the production of heating, cooling and power are especially highlighted. Important tasks have been: To quantify the following effects on the design of an integrated cooling process: the temperatures in the district heating net, available cooling water temperature (to cool the absorber and condenser), electricity price, and the composition of the energy system (e.g. fuel and CHP or power-only mode of operation). To analyze the potential of the low temperature driven chiller concept with regards to energy and cost

Investigation on Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

Development of a national anthropogenic heating database with an extrapolation for international cities

Science.gov (United States)

Sailor, David J.; Georgescu, Matei; Milne, Jeffrey M.; Hart, Melissa A.

2015-10-01

Given increasing utility of numerical models to examine urban impacts on meteorology and climate, there exists an urgent need for accurate representation of seasonally and diurnally varying anthropogenic heating data, an important component of the urban energy budget for cities across the world. Incorporation of anthropogenic heating data as inputs to existing climate modeling systems has direct societal implications ranging from improved prediction of energy demand to health assessment, but such data are lacking for most cities. To address this deficiency we have applied a standardized procedure to develop a national database of seasonally and diurnally varying anthropogenic heating profiles for 61 of the largest cities in the United Stated (U.S.). Recognizing the importance of spatial scale, the anthropogenic heating database developed includes the city scale and the accompanying greater metropolitan area. Our analysis reveals that a single profile function can adequately represent anthropogenic heating during summer but two profile functions are required in winter, one for warm climate cities and another for cold climate cities. On average, although anthropogenic heating is 40% larger in winter than summer, the electricity sector contribution peaks during summer and is smallest in winter. Because such data are similarly required for international cities where urban climate assessments are also ongoing, we have made a simple adjustment accounting for different international energy consumption rates relative to the U.S. to generate seasonally and diurnally varying anthropogenic heating profiles for a range of global cities. The methodological approach presented here is flexible and straightforwardly applicable to cities not modeled because of presently unavailable data. Because of the anticipated increase in global urban populations for many decades to come, characterizing this fundamental aspect of the urban environment - anthropogenic heating - is an essential

EPB standard EN ISO 52016: calculation of the building’s energy needs for heating and cooling, internal temperatures and heating and cooling load

NARCIS (Netherlands)

Dijk, H.A.L. van; Spiekman, M.E.; Hoes-van Oeffelen, E.C.M.

2016-01-01

EN ISO 52016-1 presents a coherent set of calculation methods at different levels of detail, for the (sensible) energy needs for the space heating and cooling and (latent) energy needs (de)humidification of a building and/or internal temperatures and heating and/or cooling loads, including the

AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER

Directory of Open Access Journals (Sweden)

Muhammad Asmail Eleiwi

2013-05-01

Full Text Available Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle.  Two cases of  vapor compression refrigeration cycle were takenin this paper:  the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin  the second case the vapor compressionrefrigeration cycle with heat exchanger ; in these two cases, the temperatureat each point of  a vapor compressionrefrigeration cycle, the low and the high pressure ,the indoor temperature andthe outdoor temperature were measured at each time at compressor speed 1450 rpmand 2900 rpm for each blower speed 1, blower speed 2 and blower speed 3.Therefrigerant fluid was used in the vapor compression refrigeration cycle withoutIHE and with IHE is R134a..

Study of entropy generation in a slab with non-uniform internal heat generation

Directory of Open Access Journals (Sweden)

El Haj Assad Mamdouh

2013-01-01

Full Text Available Analysis of entropy generation in a rectangular slab with a nonuniform internal heat generation is presented. Dimensionless local and total entropy generation during steady state heat conduction through the slab are obtained. Two different boundary conditions have been considered in the analysis, the first with asymmetric convection and the second with constant slab surface temperature. Temperature distribution within the slab is obtained analytically. The study investigates the effect of some relevant dimensionless heat transfer parameters on entropy generation. The results show that there exists a minimum local entropy generation but there does not exist a minimum total entropy generation for certain combinations of the heat transfer parameters. The results of calculations are presented graphically.

Regional Energy Planning Tool for Renewable Integrated Low-Energy District Heating Systems

DEFF Research Database (Denmark)

Tol, Hakan; Dincer, Ibrahim; Svendsen, Svend

2013-01-01

Low-energy district heating systems, operating at low temperature of 55 °C as supply and 25°C as return, can be the energy solution as being the prevailing heating infrastructure in urban areas, considering future energy schemesaiming at increased exploitation of renewable energy sources together...... with low-energy houses in focus with intensified energy efficiency measures. Employing low-temperature operation allows the ease to exploit not only any type of heat source but also low-grade sources, i.e., renewable and industrial waste heat, which would otherwise be lost. In this chapter, a regional...... energy planning tool is described considered with various energy conversion systems based on renewable energy sources to be supplied to an integrated energy infrastructure involving a low-energy district heating, a district cooling, and an electricity grid. The developed tool is performed for two case...

STEAM GENERATOR TUBE INTEGRITY ANALYSIS OF A TOTAL LOSS OF ALL HEAT SINKS ACCIDENT FOR WOLSONG NPP UNIT 1

Directory of Open Access Journals (Sweden)

HEOK-SOON LIM

2014-02-01

Full Text Available A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS and the steam generator (SG secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident.

Steam Generator Tube Integrity Analysis of A Total Loss of all Heat Sinks Accident for Wolsong NPP Unit 1

Energy Technology Data Exchange (ETDEWEB)

Lim, Heoksoon; Song, Taeyoung; Chi, Moongoo [Korea Htydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of); Kim, Seoungrae [Nuclear Engineering Service and Solution, Daejeon (Korea, Republic of)

2014-02-15

A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV) become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS) and the steam generator (SG) secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident.

Steam Generator Tube Integrity Analysis of A Total Loss of all Heat Sinks Accident for Wolsong NPP Unit 1

International Nuclear Information System (INIS)

Lim, Heoksoon; Song, Taeyoung; Chi, Moongoo; Kim, Seoungrae

2014-01-01

A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV) become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS) and the steam generator (SG) secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident

8th International Symposium on Heating, Ventilation and Air Conditioning

CERN Document Server

Zhu, Yingxin; Li, Yuguo; Vol.1 Indoor and Outdoor Environment; Vol.2 HVAC&R Component and Energy System; Vol.3 Building Simulation and Information Management

2014-01-01

Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning is based on the 8th International Symposium of the same name (ISHVAC2013), which took place in Xi’an on October 19-21, 2013. The conference series was initiated at Tsinghua University in 1991 and has since become the premier international HVAC conference initiated in China, playing a significant part in the development of HVAC and indoor environmental research and industry around the world. This international conference provided an exclusive opportunity for policy-makers, designers, researchers, engineers and managers to share their experience. Considering the recent attention on building energy consumption and indoor environments, ISHVAC2013 provided a global platform for discussing recent research on and developments in different aspects of HVAC systems and components, with a focus on building energy consumption, energy efficiency and indoor environments. These categories span a broad range of topics, and the proce...

Integrated power-heat-cold-coupling by switchable Stirling-Vuilleumier-Hybrid-Machines

International Nuclear Information System (INIS)

Kuehl, Hans-Detlev

2017-01-01

A Stirling engine consists in its so-called Gamma type on the one hand of a thermal compressor in which a double-acting displacer is the working gas between a ''hot'' and a ''warm'' (ie located on the heat use temperature level of the CHP application) cylinder chamber isochoric via a regenerator periodically shuffled back and forth. On the other hand, he has a spatially separated, one-sided working piston-cylinder system, which is connected to the ''warm'' side of the thermal compressor through an overflow and thus is at a similar temperature level. If an additional regenerator is inserted into this overflow channel, then the temperature levels are separated, since the heat output of the process takes place primarily via the warm cylinder space of the displacer system, while the cylinder space of the working piston constitutes a heat sink. This so-called ''hybrid'' process is still characterized by a - compared to the Stirling mode only slightly reduced - mechanical power output, but in addition by a theoretically equal to this magnitude, recorded on the cylinder at ''cold'' temperature cooling capacity, It thus represents an integrated system for power-heat-cold-coupling, which can be realized by a single thermodynamic process. Turning this process in the warm temperature range in addition to another, lying on the back of the working cylinder cylinder space, so that the former becomes a second, double-acting displacer, we finally get the known as a thermally driven heat pump or chiller Vuilleumier process that Ideally, no mechanical power gives or absorbs. At the Chair of Thermodynamics of the TU Dortmund, a research machine was developed and measured in a meanwhile completed research project funded by the DFG, which can switch between the three described processes and thus be adapted to changing power, heat and cooling requirements. In order to reduce the

Integrating Sustainability Education into International Marketing Curricula

Science.gov (United States)

Perera, Chamila Roshani; Hewege, Chandana Rathnasiri

2016-01-01

Purpose: The purpose of this study is to extend the current knowledge of curriculum developments in international business and marketing curricula. Integrating sustainability into business and marketing curricula of the universities are widely debated in previous literature. Sustainability is a global phenomenon; however, curriculum development…

Design, calibration and error analysis of instrumentation for heat transfer measurements in internal combustion engines

Science.gov (United States)

Ferguson, C. R.; Tree, D. R.; Dewitt, D. P.; Wahiduzzaman, S. A. H.

1987-01-01

The paper reports the methodology and uncertainty analyses of instrumentation for heat transfer measurements in internal combustion engines. Results are presented for determining the local wall heat flux in an internal combustion engine (using a surface thermocouple-type heat flux gage) and the apparent flame-temperature and soot volume fraction path length product in a diesel engine (using two-color pyrometry). It is shown that a surface thermocouple heat transfer gage suitably constructed and calibrated will have an accuracy of 5 to 10 percent. It is also shown that, when applying two-color pyrometry to measure the apparent flame temperature and soot volume fraction-path length, it is important to choose at least one of the two wavelengths to lie in the range of 1.3 to 2.3 micrometers. Carefully calibrated two-color pyrometer can ensure that random errors in the apparent flame temperature and in the soot volume fraction path length will remain small (within about 1 percent and 10-percent, respectively).

Association between Social Integration and Health among Internal Migrants in ZhongShan, China.

Directory of Open Access Journals (Sweden)

Yanwei Lin

Full Text Available Internal migrants are the individuals who migrate between regions in one country. The number of internal migrants were estimated at 245 million in China in 2013. Results were inconsistent in the literature about the relationship between their health statuses and social integration. The main difference exists on how to measure the social integration and whether health statuses of internal migrants improve with years of residence. To complement the existing literature, this study measured social integration more comprehensively and estimated the internal migrants' health statuses with varying years of residence, and explored the associations between the migrants' social integration and health. We used the data from 2014 Internal Migrant Dynamic Monitoring Survey of Health and Family Planning in ZhongShan, China. Health status was measured from four aspects: self-reported health, subjective well-being, perception of stress, mental health. We measured social integration through four dimensions: economy, social communication, acculturation, and self-identity. The analyses used multiple linear regressions to examine the associations between self-reported health, subjective well-being, and perception of stress, mental health and social integration. The analytical sample included 1,999 households of the internal migrants and 1,997 local registered households, who were permanent residents in ZhongShan. Among the internal migrants, Adults in the labor force, who were aged 25 to 44 years old, accounted for 91.2% of the internal migrant population, while 74.6% of the registered population were in that age group. Median residential time among migrants was 2.8 (1.3-6.2 years, and 20.2% of them were migrating in the same Guangdong province. Except for mental health, other health statuses among migrants had significant differences compared with local registered population, e.g. self-reported health was better, but subjective well-being was worse. However, these

Performance investigation on a 4-bed adsorption desalination cycle with internal heat recovery scheme

KAUST Repository

Thu, Kyaw

2016-10-08

Multi-bed adsorption cycle with the internal heat recovery between the condenser and the evaporator is investigated for desalination application. A numerical model is developed for a 4-bed adsorption cycle implemented with the master-and-slave configuration and the aforementioned internal heat recovery scheme. The present model captures the reversed adsorption/desorption phenomena frequently associated with the unmatched switching periods. Mesoporous silica gel and water vapor emanated from the evaporation of the seawater are employed as the adsorbent and adsorbate pair. The experimental data and investigation for such configurations are reported for the first time at heat source temperatures from 50 °C to 70 °C. The numerical model is validated rigorously and the parametric study is conducted for the performance of the cycle at assorted operation conditions such as hot and cooling water inlet temperatures and the cycle times. The specific daily water production (SDWP) of the present cycle is found to be about 10 m/day per tonne of silica gel for the heat source temperature at 70 °C. Performance comparison is conducted for various types of adsorption desalination cycles. It is observed that the AD cycle with the current configuration provides superior performance whilst is operational at unprecedentedly low heat source temperature as low as 50 °C.

Numerical and experimental investigation of melting with internal heat generation within cylindrical enclosures

Energy Technology Data Exchange (ETDEWEB)

Amber Shrivastava; Brian Williams; Ali S. Siahpush; Bruce Savage; John Crepeau

2014-06-01

There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. First a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.

A least squares method for a longitudinal fin with temperature dependent internal heat generation and thermal conductivity

International Nuclear Information System (INIS)

Aziz, A.; Bouaziz, M.N.

2011-01-01

Highlights: → Analytical solutions for a rectangular fin with temperature dependent heat generation and thermal conductivity. → Graphs give temperature distributions and fin efficiency. → Comparison of analytical and numerical solutions. → Method of least squares used for the analytical solutions. - Abstract: Approximate but highly accurate solutions for the temperature distribution, fin efficiency, and optimum fin parameter for a constant area longitudinal fin with temperature dependent internal heat generation and thermal conductivity are derived analytically. The method of least squares recently used by the authors is applied to treat the two nonlinearities, one associated with the temperature dependent internal heat generation and the other due to temperature dependent thermal conductivity. The solution is built from the classical solution for a fin with uniform internal heat generation and constant thermal conductivity. The results are presented graphically and compared with the direct numerical solutions. The analytical solutions retain their accuracy (within 1% of the numerical solution) even when there is a 60% increase in thermal conductivity and internal heat generation at the base temperature from their corresponding values at the sink temperature. The present solution is simple (involves hyperbolic functions only) compared with the fairly complex approximate solutions based on the homotopy perturbation method, variational iteration method, and the double series regular perturbation method and offers high accuracy. The simple analytical expressions for the temperature distribution, the fin efficiency and the optimum fin parameter are convenient for use by engineers dealing with the design and analysis of heat generating fins operating with a large temperature difference between the base and the environment.

Simultaneous integrated optimal energy flow of electricity, gas, and heat

International Nuclear Information System (INIS)

Shabanpour-Haghighi, Amin; Seifi, Ali Reza

2015-01-01

Highlights: • Integration of electrical, natural gas, and district heating networks is studied. • Part-load performances of units are considered in modeling. • A modified teaching–learning based optimization is used to solve the problem. • Results show the advantages of the integrated optimization approach. - Abstract: In this paper, an integrated approach to optimize electrical, natural gas, and district heating networks simultaneously is studied. Several interdependencies between these infrastructures are considered in details including a nonlinear part-load performance for boilers and CHPs besides the valve-point effect for generators. A novel approach based on selecting an appropriate set of state-variables for the problem is proposed that eliminates the addition of any new variable to convert irregular equations into a regular set while the optimization problem is still solvable. As a large optimization problem, the optimal solution cannot be achieved by conventional mathematical techniques. Hence, it is better to use evolutionary algorithms instead. In this paper, the well-known modified teaching–learning based optimization algorithm is utilized to solve the multi-period optimal power flow problem of multi-carrier energy networks. The proposed scheme is implemented and applied to a typical multi-carrier energy network. Results are compared with some other conventional heuristic algorithms and the applicability and superiority of the proposed methodology is verified

How European unification has shaped the debate on measuring international financial integration

NARCIS (Netherlands)

M. Pieterse-Bloem (Mary); S.C.W. Eijffinger (Sylvester)

2013-01-01

textabstractIn this paper we analyse a chronicle of economic theory on international financial integration post-WWII to the present date. Our focus is on theories that have somehow quantify the state and speed of international financial integration. We are able to contrast and compare three distinct

Experimental investigation on AC unit integrated with sensible heat storage (SHS)

Science.gov (United States)

Aziz, N. A.; Amin, N. A. M.; Majid, M. S. A.; Hussin, A.; Zhubir, S.

2017-10-01

The growth in population and economy has increases the energy demand and raises the concerns over the sustainable energy source. Towards the sustainable development, energy efficiency in buildings has become a prime objective. In this paper, the integration of thermal energy storage was studied. This paper presents an experimental investigation on the performance of an air conditioning unit integrated with sensible heat storage (SHS) system. The results were compared to the conventional AC systems in the terms of average electricity usage, indoor temperature and the relative humidity inside the experimented room (cabin container). Results show that the integration of water tank as an SHS reduces the electricity usage by 5%, while the integration of well-insulated water tank saves up to 8% of the electricity consumption.

Integrated heat exchanger design for a cryogenic storage tank

Energy Technology Data Exchange (ETDEWEB)

Fesmire, J. E.; Bonner, T.; Oliveira, J. M.; Johnson, W. L.; Notardonato, W. U. [NASA Kennedy Space Center, Cryogenics Test Laboratory, NE-F6, KSC, FL 32899 (United States); Tomsik, T. M. [NASA Glenn Research Center, 21000 Brookpark Road, Cleveland, OH 44135 (United States); Conyers, H. J. [NASA Stennis Space Center, Building 3225, SSC, MS 39529 (United States)

2014-01-29

Field demonstrations of liquid hydrogen technology will be undertaken for the proliferation of advanced methods and applications in the use of cryofuels. Advancements in the use of cryofuels for transportation on Earth, from Earth, or in space are envisioned for automobiles, aircraft, rockets, and spacecraft. These advancements rely on practical ways of storage, transfer, and handling of liquid hydrogen. Focusing on storage, an integrated heat exchanger system has been designed for incorporation with an existing storage tank and a reverse Brayton cycle helium refrigerator of capacity 850 watts at 20 K. The storage tank is a 125,000-liter capacity horizontal cylindrical tank, with vacuum jacket and multilayer insulation, and a small 0.6-meter diameter manway opening. Addressed are the specific design challenges associated with the small opening, complete modularity, pressure systems re-certification for lower temperature and pressure service associated with hydrogen densification, and a large 8:1 length-to-diameter ratio for distribution of the cryogenic refrigeration. The approach, problem solving, and system design and analysis for integrated heat exchanger are detailed and discussed. Implications for future space launch facilities are also identified. The objective of the field demonstration will be to test various zero-loss and densified cryofuel handling concepts for future transportation applications.

The Relation of an International Student Center's Orientation Training Sessions with International Students' Achievement and Integration to University

Science.gov (United States)

Güvendir, Meltem Acar

2018-01-01

The purpose of the research is to examine the relation of orientation training sessions with integration and achievement of the international students. The study used the Institutional Integration Scales, developed by Pascarella and Terenzini (1980), to examine the integration level of the international students. 181 freshmen undergraduate and…

Biogas production supported by excess heat – A systems analysis within the food industry

International Nuclear Information System (INIS)

Broberg Viklund, Sarah; Lindkvist, Emma

2015-01-01

Highlights: • A systems analysis when moving from external to internal production and use of biogas at an industry. • The aim is to study the impacts on greenhouse gas emissions and economics from this switch. • The study compares the choice of using biogas or industrial excess heat to heat the digester. • Internal biogas production supported by excess heat has environmental and economic benefits. - Abstract: The aim of this paper was to study the effects on greenhouse gases and economics when a change is made in the use of industrial organic waste from external production and use of biogas (A) to internal production and use (B). The two different system solutions are studied through a systems analysis based on an industrial case. The baseline system (A) and a modified system (B) were compared and analysed. Studies show that industrial processes considered as integrated systems, including the exchange of resources between industries, can result in competitive advantages. This study focuses on the integration of internally produced biogas from food industry waste produced by a food company and the use of excess heat. Two alternative scenarios were studied: (1) the use of available excess heat to heat the biogas digester and (2) the use of a part of the biogas produced to heat the biogas digester. This study showed that the system solution, whereby excess heat rather than biogas is used to heat the biogas digester, was both environmentally and economically advantageous. However, the valuation of biomass affects the magnitude of the emissions reduction. Implementing this synergistic concept will contribute to the reaching of European Union climate targets

The effects of low internal integration between purchasing and operations on suppliers’ resource mobilization

DEFF Research Database (Denmark)

Ellegaard, Chris; Koch, Christian

2012-01-01

A company that suffers from low internal integration between corporate functions performs worse than its more integrated competitors, leaving it in a position of competitive disparity. This paper reports on an investigation of the effects of internal integration between purchasing and operations...... on the mobilization of supplier resources. Low internal integration generates uncoordinated operations and purchasing behaviors that negatively affect supplier resource mobilization. We find that the lack of operations support for eight major purchasing initiatives in a construction company negatively affects...

How European unification has shaped the debate on measuring international financial integration

OpenAIRE

Pieterse-Bloem, Mary; Eijffinger, Sylvester

2013-01-01

textabstractIn this paper we analyse a chronicle of economic theory on international financial integration post-WWII to the present date. Our focus is on theories that have somehow quantify the state and speed of international financial integration. We are able to contrast and compare three distinct strands that have brought forward conditions for its measurement. It is shown that European unification provides much of the empirical testing ground for these measures of international financial ...

Stock Market Integration: Are Risk Premiums of International Assets Equal?

Directory of Open Access Journals (Sweden)

Kusdhianto Setiawan

2014-02-01

Full Text Available This paper studies previous research on capital market integration and applies a simple international capital asset pricing model by considering the incompleteness in market integration and heteroscedasticity of the market returns. When we disregarded those two factors, we found that stock markets were integrated and the law of one price on risk premiums prevails. However, when the factors were considered, the markets were just partially integrated.

Heat integration of an ethanol polygeneration plant based on lignocellulose: Comparing weak acid hydrolysis and enzymatic hydrolysis; Energiintegrerat etanolkombinat baserat paa lignocellulosa - Jaemfoerelse mellan svagsyrahydrolys och enzymhydrolys

Energy Technology Data Exchange (ETDEWEB)

Olsson, Marcus; Nordman, Roger; Taherzadeh, Mohammad

2011-07-01

Plants for bioethanol production have been planned in several cities in Sweden, including Boraas. This report provides answers to general questions regarding how such a facility's energy demand is affected by the external integration with a heat and power plant and the internal energy integration between process units. Heat integration of a bioethanol plant means that energy is reused as much as is technically possible; this sets a practical minimum level for the energy demand of the plant. In the study, ethanol production from cellulose has been simulated using Aspen Plus. Weak acid hydrolysis and enzymatic hydrolysis have been simulated, each with 50,000 and 100,000 tonnes of ethanol per year, resulting in four simulation cases. In all cases, heat integration is evaluated using pinch analysis. The steam in the ethanol plant has been covered by steam from a heat and power plant similar to that found today in Boraas. It is important to note that the energy quotas reported here includes energy use for upgrading the residual products. This leads to lower energy quotas than would be the case if the upgrading of residuals were allocated outside of the ethanol production. The conclusions from the project are: - The steam demand of the ethanol plant leads to a reduction in both the electricity and heat production of the heat and power plant. For the weak acid hydrolysis, the electricity loss is relatively high, 26-98%, which will affect the revenue significantly. The loss of electricity production is lower for the enzymatic process: 11-47%. - The difference in decreased electricity between the theoretical case of heating the raw material and the two alternative heating cases is about a factor of two, so the design of the heating of raw material is extremely important. - The reduced heat output of the power plant can, in most cases, be balanced by the surplus heat from the ethanol plant, but to completely balance the shortage, heat over 100 deg C must be used

Integrated Energy & Emission Management for Heavy-Duty Diesel Engines with Waste Heat Recovery System

NARCIS (Netherlands)

Willems, F.P.T.; Kupper, F.; Cloudt, R.P.M.

2012-01-01

This study presents an integrated energy and emission management strategy for an Euro-VI diesel engine with Waste Heat Recovery (WHR) system. This Integrated Powertrain Control (IPC) strategy optimizes the CO2-NOx trade-off by minimizing the operational costs associated with fuel and AdBlue

More Wind Power Integration with Adjusted Energy Carriers for Space Heating in Northern China

Directory of Open Access Journals (Sweden)

Jianjun He

2012-08-01

Full Text Available In Northern China, due to the high penetration of coal-fired cogeneration facilities, which are generally equipped with extraction-condensing steam turbines, lots of wind power resources may be wasted during the heating season. In contrast, considerable coal is consumed in the power generation sector. In this article, firstly it is revealed that there exists a serious divergence in the ratio of electrical to thermal energy between end users’ demand and the cogenerations’ production during off-peak load at night, which may negate active power-balancing of the electric power grid. Secondly, with respect to this divergence only occurring during off-peak load at night, a temporary proposal is given so as to enable the integration of more wind power. The authors suggest that if the energy carrier for part of the end users’ space heating is switched from heating water to electricity (e.g., electric heat pumps (EHPs can provide space heating in the domestic sector, the ratio of electricity to heating water load should be adjusted to optimize the power dispatch between cogeneration units and wind turbines, resulting in fuel conservation. With this proposal, existing infrastructures are made full use of, and no additional ones are required. Finally a numerical simulation is performed in order to illustrate both the technical and economic feasibility of the aforementioned proposal, under ongoing infrastructures as well as electricity and space heating tariff conditions without changing participants’ benefits. The authors aim to persuade Chinese policy makers to enable EHPs to provide space heating to enable the integration of more wind power.

14th International Conference on Integral Methods in Science and Engineering

CERN Document Server

Riva, Matteo; Lamberti, Pier; Musolino, Paolo

2017-01-01

This contributed volume contains a collection of articles on the most recent advances in integral methods.  The first of two volumes, this work focuses on the construction of theoretical integral methods. Written by internationally recognized researchers, the chapters in this book are based on talks given at the Fourteenth International Conference on Integral Methods in Science and Engineering, held July 25-29, 2016, in Padova, Italy. A broad range of topics is addressed, such as: • Integral equations • Homogenization • Duality methods • Optimal design • Conformal techniques This collection will be of interest to researchers in applied mathematics, physics, and mechanical and electrical engineering, as well as graduate students in these disciplines, and to other professionals who use integration as an essential tool in their work.

Thermodynamic evaluation of CHP (combined heat and power) plants integrated with installations of coal gasification

International Nuclear Information System (INIS)

Ziębik, Andrzej; Malik, Tomasz; Liszka, Marcin

2015-01-01

Integration of a CHP steam plant with an installation of coal gasification and gas turbine leads to an IGCC-CHP (integrated gasification combined cycle-combined heat and power). Two installations of coal gasification have been analyzed, i.e. pressurized entrained flow gasifier – case 1 and pressurized fluidized bed gasifier with CO_2 recirculation – case 2. Basing on the results of mathematical modelling of an IGCC-CHP plant, the algorithms of calculating typical energy indices have been derived. The following energy indices are considered, i.e. coefficient of heat performance and relative savings of chemical energy of fuels. The results of coefficients of heat performance are contained between 1.87 and 2.37. Values exceeding 1 are thermodynamically justified because the idea of cogeneration of heat and electricity based on combining cycles of the heat engine and heat pump the efficiency of which exceeds 1. Higher values concerning waste heat replace more thermodynamically effective sources of heat in CHP plants. Relative savings of the chemical energy of fuels are similar in both cases of IGCC-CHP plants and are contained between the lower value of the CHP (combined heat and power) plants fuelled with coal and higher value of CHP plants fired with natural gas. - Highlights: • Energy savings of fuel is an adequate measure of cogeneration. • Relative energy savings of IGCC-CHP is near the result of a gas and steam CHP. • COHP (coefficient of heat performance) can help to divide fuel between heat fluxes. • Higher values of COHP in the case of waste heat recovery result from the lower thermal parameters.

EFFICIENT USE OF ENERGY IN A ELECTRIC ARC FURNANCE BY HEAT INTEGRATION APPROACH

OpenAIRE

Umesh Kumar, Dr. A K Prasad, Sourabh Kumar Soni

2016-01-01

Based on the principles of heat integration, the present work investigates the design and operational modifications which can lead to efficient energy integration in an electric arc furnace being operated with direct reduction process. This process is one of the oldest and most widely applied processes amongst the commercially used process in India. For the purpose of energy integration stream data is extracted from the actual flow sheet of the plant, which consists of supply and target tempe...

Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics

Energy Technology Data Exchange (ETDEWEB)

Surducan, E.; Surducan, V.; Neamtu, C., E-mail: camelia.neamtu@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies (INCDTIM), 67-103 Donat St., 400293, Cluj‑Napoca (Romania); Limare, A.; Di Giuseppe, E. [Institut de Physique du Globe de Paris (IPGP), Univ. Paris Diderot, UMR CNRS 7154, 1 rue Jussieu, 75005, Paris (France)

2014-12-15

We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm{sup 3} convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

The effect of internal ribbing on forced convective heat transfer in circular-sectioned tubes

International Nuclear Information System (INIS)

Farhadi Rahmat-Abadi, K.; Morris, W. D.

2003-01-01

This paper presents the results of an experimental examination of the effect of internal circumferential ribs on forced convection in circular-sectioned tubes. The work is relevant to the internal cooling of gas turbine rotor blades. The influence of rib geometry is investigated for three different rib configurations and simple design-type, empirical equations are developed for estimating heat transfer at rib and mid-rib locations. It is demonstrated that heat transfer may be improved by up to three fold in relation to fully developed forced convection in smooth-walled tubes. The geometric parameters which have been used for the experiments are typical of those currently applied to gas turbine blade cooling designs

Hydrogen and renewable energy sources integrated system for greenhouse heating

Directory of Open Access Journals (Sweden)

Ileana Blanco

2013-09-01

Full Text Available A research is under development at the Department of Agro- Environmental Sciences of the University of Bari “Aldo Moro” in order to investigate the suitable solutions of a power system based on solar energy (photovoltaic and hydrogen, integrated with a geothermal heat pump for powering a self sustained heated greenhouse. The electrical energy for heat pump operation is provided by a purpose-built array of solar photovoltaic modules, which supplies also a water electrolyser system controlled by embedded pc; the generated dry hydrogen gas is conserved in suitable pressured storage tank. The hydrogen is used to produce electricity in a fuel cell in order to meet the above mentioned heat pump power demand when the photovoltaic system is inactive during winter night-time or the solar radiation level is insufficient to meet the electrical demand. The present work reports some theoretical and observed data about the electrolyzer operation. Indeed the electrolyzer has required particular attention because during the experimental tests it did not show a stable operation and it was registered a performance not properly consistent with the predicted performance by means of the theoretical study.

Estimation of internal heat transfer coefficients and detection of rib positions in gas turbine blades from transient surface temperature measurements

International Nuclear Information System (INIS)

Heidrich, P; Wolfersdorf, J v; Schmidt, S; Schnieder, M

2008-01-01

This paper describes a non-invasive, non-destructive, transient inverse measurement technique that allows one to determine internal heat transfer coefficients and rib positions of real gas turbine blades from outer surface temperature measurements after a sudden flow heating. The determination of internal heat transfer coefficients is important during the design process to adjust local heat transfer to spatial thermal load. The detection of rib positions is important during production to fulfill design and quality requirements. For the analysis the one-dimensional transient heat transfer problem inside of the turbine blade's wall was solved. This solution was combined with the Levenberg-Marquardt method to estimate the unknown boundary condition by an inverse technique. The method was tested with artificial data to determine uncertainties with positive results. Then experimental testing with a reference model was carried out. Based on the results, it is concluded that the presented inverse technique could be used to determine internal heat transfer coefficients and to detect rib positions of real turbine blades.

NASA Physical Sciences - Presentation to Annual Two Phase Heat Transfer International Topical Team Meeting

Science.gov (United States)

Chiaramonte, Francis; Motil, Brian; McQuillen, John

2014-01-01

The Two-phase Heat Transfer International Topical Team consists of researchers and members from various space agencies including ESA, JAXA, CSA, and RSA. This presentation included descriptions various fluid experiments either being conducted by or planned by NASA for the International Space Station in the areas of two-phase flow, flow boiling, capillary flow, and crygenic fluid storage.

The role of large‐scale heat pumps for short term integration of renewable energy

DEFF Research Database (Denmark)

Mathiesen, Brian Vad; Blarke, Morten; Hansen, Kenneth

2011-01-01

technologies is focusing on natural working fluid hydrocarbons, ammonia, and carbon dioxide. Large-scale heat pumps are crucial for integrating 50% wind power as anticipated to be installed in Denmark in 2020, along with other measures. Also in the longer term heat pumps can contribute to the minimization...... savings with increased wind power and may additionally lead to economic savings in the range of 1,500-1,700 MDKK in total in the period until 2020. Furthermore, the energy system efficiency may be increased due to large heat pumps replacing boiler production. Finally data sheets for large-scale ammonium......In this report the role of large-scale heat pumps in a future energy system with increased renewable energy is presented. The main concepts for large heat pumps in district heating systems are outlined along with the development for heat pump refrigerants. The development of future heat pump...

Energy efficiency analysis of styrene production by adiabatic ethylbenzene dehydrogenation using exergy analysis and heat integration

Directory of Open Access Journals (Sweden)

Ali Emad

2018-03-01

Full Text Available Styrene is a valuable commodity for polymer industries. The main route for producing styrene by dehydrogenation of ethylbenzene consumes a substantial amount of energy because of the use of high-temperature steam. In this work, the process energy requirements and recovery are studied using Exergy analysis and Heat Integration (HI based on Pinch design method. The amount of steam plays a key role in the trade-off between Styrene yield and energy savings. Therefore, optimizing the operating conditions for energy reduction is infeasible. Heat integration indicated an insignificant reduction in the net energy demand and exergy losses, but 24% and 34% saving in external heating and cooling duties, respectively. When the required steam is generated by recovering the heat of the hot reactor effluent, a considerable saving in the net energy demand, as well as the heating and cooling utilities, can be achieved. Moreover, around 68% reduction in the exergy destruction is observed.

Control strategy on the double-diffusive convection in a nanofluid layer with internal heat generation

Science.gov (United States)

Mokhtar, N. F. M.; Khalid, I. K.; Siri, Z.; Ibrahim, Z. B.; Gani, S. S. A.

2017-10-01

The influences of feedback control and internal heat source on the onset of Rayleigh-Bénard convection in a horizontal nanofluid layer is studied analytically due to Soret and Dufour parameters. The confining boundaries of the nanofluid layer (bottom boundary-top boundary) are assumed to be free-free, rigid-free, and rigid-rigid, with a source of heat from below. Linear stability theory is applied, and the eigenvalue solution is obtained numerically using the Galerkin technique. Focusing on the stationary convection, it is shown that there is a positive thermal resistance in the presence of feedback control on the onset of double-diffusive convection, while there is a positive thermal efficiency in the existence of internal heat generation. The possibilities of suppress or augment of the Rayleigh-Bénard convection in a nanofluid layer are also discussed in detail.

High Temperature Heat Pump Integration using Zeotropic Working Fluids for Spray Drying Facilities

DEFF Research Database (Denmark)

Zühlsdorf, Benjamin; Bühler, Fabian; Mancini, Roberta

2017-01-01

source and sink best possibly. Therefore, a set of six common working fluids is defined and the possible binary mixtures of these fluids are analyzed. The performance of the fluids is evaluated based on the energetic performance (COP) and the economic potential (NPV). The results show...... and show a large potential to reuse the excess heat from exhaust gases. This study analyses a heat pump application with an improved integration by choosing the working fluid as a mixture in such a way, that the temperature glide during evaporation and condensation matches the temperature glide of the heat...

International Space Station Configuration Analysis and Integration

Science.gov (United States)

Anchondo, Rebekah

2016-01-01

Ambitious engineering projects, such as NASA's International Space Station (ISS), require dependable modeling, analysis, visualization, and robotics to ensure that complex mission strategies are carried out cost effectively, sustainably, and safely. Learn how Booz Allen Hamilton's Modeling, Analysis, Visualization, and Robotics Integration Center (MAVRIC) team performs engineering analysis of the ISS Configuration based primarily on the use of 3D CAD models. To support mission planning and execution, the team tracks the configuration of ISS and maintains configuration requirements to ensure operational goals are met. The MAVRIC team performs multi-disciplinary integration and trade studies to ensure future configurations meet stakeholder needs.

13th International Conference on Integral Methods in Science and Engineering

CERN Document Server

Kirsch, Andreas

2015-01-01

This contributed volume contains a collection of articles on state-of-the-art developments on the construction of theoretical integral techniques and their application to specific problems in science and engineering.  Written by internationally recognized researchers, the chapters in this book are based on talks given at the Thirteenth International Conference on Integral Methods in Science and Engineering, held July 21–25, 2014, in Karlsruhe, Germany.   A broad range of topics is addressed, from problems of existence and uniqueness for singular integral equations on domain boundaries to numerical integration via finite and boundary elements, conservation laws, hybrid methods, and other quadrature-related approaches.   This collection will be of interest to researchers in applied mathematics, physics, and mechanical and electrical engineering, as well as graduate students in these disciplines and other professionals for whom integration is an essential tool.

Optimal Operation and Stabilising Control of the Concentric Heat-Integrated Distillation Column

DEFF Research Database (Denmark)

Bisgaard, Thomas; Skogestad, Sigurd; Huusom, Jakob Kjøbsted

2016-01-01

A systematic control structure design method is applied on the concentric heat integrated distillation column (HIDiC) separating benzene and toluene. A degrees of freedom analysis is provided for identifying potential manipulated and controlled variables. Optimal operation is mapped and active...

Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

Directory of Open Access Journals (Sweden)

Wail Aladayleh

2015-01-01

Full Text Available This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.

Integrating rather than juxtaposing environmental policy and the internal market

NARCIS (Netherlands)

Vedder, Hans; Koutrakos, Panos; Snell, Jukka

2017-01-01

This contribution to the research handbook on the internal market describes and analyses the case law on environmental measures that impact the internal market and notably the free movement of goods. It argues that an integration may be better for both environmental protection and market

Book of short papers : International symposium on convective heat and mass transfer in sustainable energy Conv - 09. Volume 1

International Nuclear Information System (INIS)

2009-01-01

This book contains the short papers from the International Symposium on Convective heat and Mass Transfer in sustainable Energy ( Conv-09), organized on behalf of the International Centre for Heat and Mass Transfer, it was held on April 26- 1st May, In Hammamet, Tunisia. The objective of this conference is to bring together researchers in a forum to exchange innovative ideas, methods and results, and visions of the future related to the general theme of convective heat and mass transfer

Book of short papers : International symposium on convective heat and mass transfer in sustainable energy conv - 09. Volume 2

International Nuclear Information System (INIS)

2009-01-01

This book contains the short papers from the International Symposium on convective heat and Mass Transfer in sustainable Energy ( conv-09), organized on behalf of the International Centre for Heat and Mass Transfer, it was held on April 26- 1st May, In Hammamet, Tunisia. The objective of this conference is to bring together researchers in a forum to exchange innovative ideas, methods and results, and visions of the future related to the general theme of convective heat and mass transfer

Optimal operation of integrated processes. Studies on heat recovery systems

Energy Technology Data Exchange (ETDEWEB)

Glemmestad, Bjoern

1997-12-31

Separators, reactors and a heat exchanger network (HEN) for heat recovery are important parts of an integrated plant. This thesis deals with the operation of HENs, in particular, optimal operation. The purpose of heat integration is to save energy, but the HEN also introduces new interactions and feedback into the overall plant. A prerequisite for optimisation is that there are extra degrees of freedom left after regulatory control is implemented. It is shown that extra degrees of freedom may not always be utilized for energy optimisation, and a quantitative expression for the degrees of freedom that can be so utilized are presented. A simplified expression that is often valid is also deduced. The thesis presents some improvements and generalisations of a structure based method that has been proposed earlier. Structural information is used to divide possible manipulations into three categories depending on how each manipulation affects the utility consumption. By means of these categories and two heuristic rules for operability, the possible manipulations are ordered in a priority table. This table is used to determine which manipulation should be preferred and which manipulation should be selected if an active manipulation is saturated. It is shown that the method may correspond to split-range control. A method that uses parametric information in addition to structural information is proposed. In this method, the optimal control structure is found through solving an integer programming problem. The thesis also proposes a method that combines the use of steady state optimisation and optimal selection of measurements. 86 refs., 46 figs., 8 tabs.

Challenges faced by international nurses when migrating: an integrative literature review.

Science.gov (United States)

Pung, L-X; Goh, Y-S

2017-03-01

Results from this literature review were used to identify the challenges faced by international nurses in their host countries following migration. The increasing strain of nursing shortages in the healthcare system has led to the recruitment of international nurses among many countries. However, following migration, international nurses are faced with challenges that may result in poor integration with their host countries. Using Cooper's five stages for integrative research reviews, a literature search was conducted across seven databases using a PRISMA search strategy. Additional manual searches were also conducted on the end-references of the retrieved articles. The authors then independently reviewed the selected articles using the Joanna Briggs Institute appraisal form to extract and generate the themes for the review. Twenty-four articles were selected for the review. The themes generated included: (i) difficulty orientating; (ii) a longing for what is missing; (iii) professional development and devaluing; (iv) communication barriers; (v) discrimination and marginalization; (vi) personal and professional differences; and (vii) a meaningful support system. By identifying the challenges faced by international nurses, interventions that ensure equal treatment (e.g. multifaceted transition programmes and culturally sensitive 'buddy' systems) can be implemented to help international nurses adapt to their new environments. Adequate communication can be achieved by encouraging international nurses to speak English and learn the colloquial language and non-verbal behaviours used by native nurses. With good integration international nurses may be able to reach their full career potential as professional nurses in their host countries. The adaptation process is a dynamic process that requires effort from both international and native nurses. Thus, any strategies that are developed and implemented must be multifaceted. © 2016 International Council of Nurses.

Integrated care in an international perspective: EUPHA proceedings December 2001.

NARCIS (Netherlands)

Delnoij, D.; Klazinga, N.; Kulu Glasgow, I.

2002-01-01

The workshop of the EUPHA section Health Services Research took place on Thursday, December 8th, 2001 in Brussels at the annual conference of the EUPHA (European Public Health Association). The theme of the workshop was integrated care in an international perspective. Integrated care can be defined

Formation and sustainment of internal transport barriers in the International Thermonuclear Experimental Reactor with the baseline heating mix

Energy Technology Data Exchange (ETDEWEB)

Poli, Francesca M.; Kessel, Charles E. [Princeton Plasma Physics laboratory, Princeton, New Jersey 08543 (United States)

2013-05-15

Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved confinement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current profiles and negative magnetic shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. The time-dependent transport simulations indicate that, with a trade-off of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating configuration.

Formation and sustainment of internal transport barriers in the International Thermonuclear Experimental Reactor with the baseline heating mixa)

Science.gov (United States)

Poli, Francesca M.; Kessel, Charles E.

2013-05-01

Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved confinement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current profiles and negative magnetic shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. The time-dependent transport simulations indicate that, with a trade-off of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating configuration.

Integration of solar process heat into an existing thermal desalination plant in Qatar

Science.gov (United States)

Dieckmann, S.; Krishnamoorthy, G.; Aboumadi, M.; Pandian, Y.; Dersch, J.; Krüger, D.; Al-Rasheed, A. S.; Krüger, J.; Ottenburger, U.

2016-05-01

The water supply of many countries in the Middle East relies mainly on water desalination. In Qatar, the water network is completely fed with water from desalination plants. One of these power and desalination plants is located in Ras Abu Fontas, 20 km south of the capital Doha. The heat required for thermal desalination is provided by steam which is generated in waste heat recovery boilers (HRB) connected to gas turbines. Additionally, gas fired boilers or auxiliary firing in the HRBs are used in order to decouple the water generation from the electricity generation. In Ras Abu Fontas some auxiliary boilers run 24/7 because the HRB capacity does not match the demand of the desalination units. This paper contains the techno-economic analysis of two large-scale commercial solar field options, which could reduce the fuel consumption significantly. Both options employ parabolic trough technology with a nominal saturated steam output of 350 t/h at 15 bar (198°C, 240 MW). The first option uses direct steam generation without storage while the second relies on common thermal oil in combination with a molten salt thermal storage with 6 hours full-load capacity. The economic benefit of the integration of solar power depends mainly on the cost of the fossil alternative, and thus the price (respectively opportunity costs) of natural gas. At a natural gas price of 8 US-/MMBtu the internal rate of return on equity (IRR) is expected at about 5%.

Low temperature heat capacities and thermodynamic functions described by Debye-Einstein integrals.

Science.gov (United States)

Gamsjäger, Ernst; Wiessner, Manfred

2018-01-01

Thermodynamic data of various crystalline solids are assessed from low temperature heat capacity measurements, i.e., from almost absolute zero to 300 K by means of semi-empirical models. Previous studies frequently present fit functions with a large amount of coefficients resulting in almost perfect agreement with experimental data. It is, however, pointed out in this work that special care is required to avoid overfitting. Apart from anomalies like phase transformations, it is likely that data from calorimetric measurements can be fitted by a relatively simple Debye-Einstein integral with sufficient precision. Thereby, reliable values for the heat capacities, standard enthalpies, and standard entropies at T  = 298.15 K are obtained. Standard thermodynamic functions of various compounds strongly differing in the number of atoms in the formula unit can be derived from this fitting procedure and are compared to the results of previous fitting procedures. The residuals are of course larger when the Debye-Einstein integral is applied instead of using a high number of fit coefficients or connected splines, but the semi-empiric fit coefficients keep their meaning with respect to physics. It is suggested to use the Debye-Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis. Additional fitting is recommended when a precise description for data at ultra-low temperatures (0-20 K) is requested.

Thermal management of a multiple mini-channel heat sink by the integration of a thermal responsive shape memory material

International Nuclear Information System (INIS)

Di Maio, E.; Mastrullo, R.; Mauro, A.W.; Toto, D.

2014-01-01

In this paper, a novel application of a thermo-responsive shape memory polymer (SMP) is proposed to smart-control the forced flow of water in a multi mini-channel heat sink. In particular, it is reported that millimeter-sized cylinders made of SMP could be used to smartly obstruct the fluid flow by adapting the flow cross section to the heat load to be removed. By integrating the sensing, the control and the actuation functions within a unique, millimeter-sized device, these micro-valves, unlike the traditional actuators normally used for flow control, could be easily embedded into small heat sinks, with significant space and energy saving, useful, in particular, in systems where several miniaturized components have to be cooled concurrently, such as the modern mainframes or the concentrated photovoltaic solar cells. Two possible configurations for the SMP were considered in this study: an “open” configuration, without any obstruction of the water flow free and an “obstructed” configuration, with the millimeter-sized cylinder partially occupying the mini-channel. A numerical, steady state analysis was carried out with water in single-phase forced convection, to determine the effect of these two states on the internal fluid flow characteristics under different conditions of heat flux and pressure drop and to evaluate the overall thermal behavior of the smart-controlled multiple mini-channel heat sink in terms of ability to control the temperature of the system and to reduce the energy consumption. -- Highlights: • A novel application of a SMP material is investigated for the thermal management of a heat sink. • Numerical simulations to find the matching of the heat sink and material system after regulation were carried out. • The investigated system is able to control the heat sink temperature. • Further analysis for system stability are required

Integral staggered point-matching method for millimeter-wave reflective diffraction gratings on electron cyclotron heating systems

International Nuclear Information System (INIS)

Xia, Donghui; Huang, Mei; Wang, Zhijiang; Zhang, Feng; Zhuang, Ge

2016-01-01

Highlights: • The integral staggered point-matching method for design of polarizers on the ECH systems is presented. • The availability of the integral staggered point-matching method is checked by numerical calculations. • Two polarizers are designed with the integral staggered point-matching method and the experimental results are given. - Abstract: The reflective diffraction gratings are widely used in the high power electron cyclotron heating systems for polarization strategy. This paper presents a method which we call “the integral staggered point-matching method” for design of reflective diffraction gratings. This method is based on the integral point-matching method. However, it effectively removes the convergence problems and tedious calculations of the integral point-matching method, making it easier to be used for a beginner. A code is developed based on this method. The calculation results of the integral staggered point-matching method are compared with the integral point-matching method, the coordinate transformation method and the low power measurement results. It indicates that the integral staggered point-matching method can be used as an optional method for the design of reflective diffraction gratings in electron cyclotron heating systems.

Integral staggered point-matching method for millimeter-wave reflective diffraction gratings on electron cyclotron heating systems

Energy Technology Data Exchange (ETDEWEB)

Xia, Donghui [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, 430074 Wuhan (China); Huang, Mei [Southwestern Institute of Physics, 610041 Chengdu (China); Wang, Zhijiang, E-mail: wangzj@hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, 430074 Wuhan (China); Zhang, Feng [Southwestern Institute of Physics, 610041 Chengdu (China); Zhuang, Ge [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, 430074 Wuhan (China)

2016-10-15

Highlights: • The integral staggered point-matching method for design of polarizers on the ECH systems is presented. • The availability of the integral staggered point-matching method is checked by numerical calculations. • Two polarizers are designed with the integral staggered point-matching method and the experimental results are given. - Abstract: The reflective diffraction gratings are widely used in the high power electron cyclotron heating systems for polarization strategy. This paper presents a method which we call “the integral staggered point-matching method” for design of reflective diffraction gratings. This method is based on the integral point-matching method. However, it effectively removes the convergence problems and tedious calculations of the integral point-matching method, making it easier to be used for a beginner. A code is developed based on this method. The calculation results of the integral staggered point-matching method are compared with the integral point-matching method, the coordinate transformation method and the low power measurement results. It indicates that the integral staggered point-matching method can be used as an optional method for the design of reflective diffraction gratings in electron cyclotron heating systems.

Heat pumps in combined heat and power systems

DEFF Research Database (Denmark)

Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

2014-01-01

Heat pumps have previously been proposed as a way to integrate higher amounts of renewable energy in DH (district heating) networks by integrating, e.g., wind power. The paper identifies and compares five generic configurations of heat pumps in DH systems. The operational performance...... of the considered cases. When considering a case where the heat pump is located at a CHP (combined heat and power) plant, a configuration that increases the DH return temperature proposes the lowest operation cost, as low as 12 EUR MWh-1 for a 90 °C e 40 °C DH network. Considering the volumetric heating capacity......, a third configuration is superior in all cases. Finally, the three most promising heat pump configurations are integrated in a modified PQ-diagram of the CHP plant. Each show individual advantages, and for two, also disadvantages in order to achieve flexible operation....

Integration of Heat Transfer, Stress, and Particle Trajectory Simulation

Energy Technology Data Exchange (ETDEWEB)

Thuc Bui; Michael Read; Lawrence ives

2012-05-17

Calabazas Creek Research, Inc. developed and currently markets Beam Optics Analyzer (BOA) in the United States and abroad. BOA is a 3D, charged particle optics code that solves the electric and magnetic fields with and without the presence of particles. It includes automatic and adaptive meshing to resolve spatial scales ranging from a few millimeters to meters. It is fully integrated with CAD packages, such as SolidWorks, allowing seamless geometry updates. The code includes iterative procedures for optimization, including a fully functional, graphical user interface. Recently, time dependent, particle in cell capability was added, pushing particles synchronically under quasistatic electromagnetic fields to obtain particle bunching under RF conditions. A heat transfer solver was added during this Phase I program. Completed tasks include: (1) Added a 3D finite element heat transfer solver with adaptivity; (2) Determined the accuracy of the linear heat transfer field solver to provide the basis for development of higher order solvers in Phase II; (3) Provided more accurate and smoother power density fields; and (4) Defined the geometry using the same CAD model, while maintaining different meshes, and interfacing the power density field between the particle simulator and heat transfer solvers. These objectives were achieved using modern programming techniques and algorithms. All programming was in C++ and parallelization in OpenMP, utilizing state-of-the-art multi-core technology. Both x86 and x64 versions are supported. The GUI design and implementation used Microsoft Foundation Class.

Integrated international safeguards concepts for fuel reprocessing

International Nuclear Information System (INIS)

Hakkila, E.A.; Gutmacher, R.G.; Markin, J.T.; Shipley, J.P.; Whitty, W.J.; Camp, A.L.; Cameron, C.P.; Bleck, M.E.; Ellwein, L.B.

1981-12-01

This report is the fourth in a series of efforts by the Los Alamos National Laboratory and Sandia National Laboratories, Albuquerque, to identify problems and propose solutions for international safeguarding of light-water reactor spent-fuel reprocessing plants. Problem areas for international safeguards were identified in a previous Problem Statement (LA-7551-MS/SAND79-0108). Accounting concepts that could be verified internationally were presented in a subsequent study (LA-8042). Concepts for containment/surveillance were presented, conceptual designs were developed, and the effectiveness of these designs was evaluated in a companion study (SAND80-0160). The report discusses the coordination of nuclear materials accounting and containment/surveillance concepts in an effort to define an effective integrated safeguards system. The Allied-General Nuclear Services fuels reprocessing plant at Barnwell, South Carolina, was used as the reference facility

A new graphical method for Pinch Analysis applications: Heat exchanger network retrofit and energy integration

International Nuclear Information System (INIS)

Gadalla, Mamdouh A.

2015-01-01

Energy integration is a key solution in chemical process and crude refining industries to minimise external fuel consumption and to face the impact of growing energy crises. Typical energy integration projects can reach a reduction of heating fuels and cold utilities by up to 40% compared with original designs or existing installations. Pinch Analysis is a leading tool and regarded as an efficient method to increase energy efficiency and minimise fuel flow consumptions. It is valid for both natures of design, grassroots and retrofit situations. It can practically be applied to synthesise a HEN (heat exchanger network) or modify an existing preheat train for minimum energy consumption. Heat recovery systems or HENs are networks for exchanging heat between hot and cold process sources. All heat transferred from hot process sources into cold process sinks represent the scope for energy integration. On the other hand, energies required beyond this integrated amount are to be satisfied by external utilities. Graphical representations of Pinch Analysis, such as Composite and Grand Composite Curves are very useful for grassroots designs. Nevertheless, in retrofit situation the analysis is not adequate and besides it is graphically tedious to represent existing exchangers on such graphs. This research proposes a new graphical method for the analysis of heat recovery systems, applicable to HEN retrofit. The new graphical method is based on plotting temperatures of process hot streams versus temperatures of process cold streams. A new graph is constructed for representing existing HENs. For a given network, each existing exchanger is represented by a straight line, whose slope is proportional to the ratio of heat capacities and flows. Further, the length of each exchanger line is related to the heat flow transferred across this exchanger. This new graphical representation can easily identify exchangers across the pinch, Network Pinch, pinching matches and improper placement

Excess heat from kraft pulp mills: Trade-offs between internal and external use in the case of Sweden-Part 1: Methodology

International Nuclear Information System (INIS)

Svensson, Inger-Lise; Joensson, Johanna; Berntsson, Thore; Moshfegh, Bahram

2008-01-01

Excess heat from a kraft pulp mill can be used either internally to increase the level of efficiency in the mill, or externally for example as district heating. This paper presents an approach to investigate the competition between external and internal use through modelling the pulp mill and an energy company (ECO) within the same system boundary. Three different sizes of ECOs with different district heating demands are studied. To investigate the competitiveness of using industrial excess heat as district heating compared with other heat production techniques, the option of investing in excess heat use is introduced, along with the possibility for the ECO to invest in biomass combined heat and power (CHP), waste CHP and natural gas combined cycle (NGCC). To evaluate the robustness of the model, alternative solutions are identified and will be used as a comparison to the optimal solutions. The model has been verified by comparing the results with previous studies concerning kraft pulp mills and with related studies regarding district heating and real ECOs. Finally, the approach presented in this part of the study will be used in the second part in order to investigate the trade-off between internal and external use of excess heat under different future energy market scenarios

Optimal Operation of the Integrated Electrical and Heating Systems to Accommodate the Intermittent Renewable Sources

DEFF Research Database (Denmark)

Li, Jinghua; Fang, Jiakun; Zeng, Qing

2016-01-01

The integration of electrical and heating systems has great potential to enhance the flexibility of power systems to accommodate more renewable power such as the wind and solar. This study was to investigate an optimal way to integrate the energy of both systems in urban areas. The amount of energy...... the effectiveness of the proposed solution. The results showed that coordinated optimization of the energy distribution have significant benefits for reducing wind curtailment, operation cost, and energy losses. The proposed model and methodology could help system operators with decision support in the emerging...... conversion between the electrical system and heating system was optimally decided so that the demand within both systems could be met at the least operational cost. Besides, the best node to join with the electrical system and heating system was chosen by consideration of the energy transmission loss...

Heat stress and reduced plane of nutrition decreases intestinal integrity and function in pigs.

Science.gov (United States)

Pearce, S C; Mani, V; Weber, T E; Rhoads, R P; Patience, J F; Baumgard, L H; Gabler, N K

2013-11-01

Heat stress can compromise intestinal integrity and induce leaky gut in a variety of species. Therefore, the objectives of this study were to determine if heat stress (HS) directly or indirectly (via reduced feed intake) increases intestinal permeability in growing pigs. We hypothesized that an increased heat-load causes physiological alterations to the intestinal epithelium, resulting in compromised barrier integrity and altered intestinal function that contributes to the overall severity of HS-related illness. Crossbred gilts (n=48, 43±4 kg BW) were housed in constant climate controlled rooms in individual pens and exposed to 1) thermal neutral (TN) conditions (20°C, 35-50% humidity) with ad libitum intake, 2) HS conditions (35°C, 20-35% humidity) with ad libitum feed intake, or 3) pair-fed in TN conditions (PFTN) to eliminate confounding effects of dissimilar feed intake. Pigs were sacrificed at 1, 3, or 7 d of environmental exposure and jejunum samples were mounted into modified Ussing chambers for assessment of transepithelial electrical resistance (TER) and intestinal fluorescein isothiocyanate (FITC)-labeled lipopolysaccharide (LPS) permeability (expressed as apparent permeability coefficient, APP). Further, gene and protein markers of intestinal integrity and stress were assessed. Irrespective of d of HS exposure, plasma endotoxin levels increased 45% (Pwarm summer months.

Integrated energy and emission management for heavy-duty diesel engines with waste heat recovery system

NARCIS (Netherlands)

Willems, F.P.T.; Kupper, F.; Cloudt, R.P.M.

2012-01-01

This study presents an integrated energy and emission management strategy for an Euro-VI diesel engine with Waste Heat Recovery (WHR) system. This Integrated Powertrain Control (IPC) strategy optimizes the CO2-NOx trade-off by minimizing the operational costs associated with fuel and AdBlue

A three-dimensional analyses of fluid flow and heat transfer for moderator integrity assessment in PHWR

International Nuclear Information System (INIS)

Bang, K. H.; Lee, J. Y.; Yoo, S. O.; Kim, M. W.; Kim, H. J.

2002-01-01

Three-dimensional analyses of fluid flow and heat transfer has been performed in this study. The simulation of SPEL experimental work and comparison with experimental data has been carried out to verify the analyses models. Moreover, to verify the CANDU-6 reactor type, analyses of fluid flow and heat transfer in the calandria under the condition of steady state has been performed using FLUENT code, which is the conventional code for a three-dimensional analyses of fluid flow and heat transfer for moderator integrity assessment in PHWR thermal-hydraulics. It is found that the maximum temperature in the moderator is 347K (74 ), so that the moderator has the enough subcoolability to ensure the integrity of pressure tube during LOCA conditions

International Product Market Integration, Rents and Wage Formation

DEFF Research Database (Denmark)

Sørensen, Allan

including product market rents and the possibility that jobs may be relocated across national labour markets. Possibilities and threats, however, will not in general be uniformly distributed across firms and therefore groups in the labour market. These issues are explored in a Ricardian trade model......International product market integration enhances both export possibilities through easier access to foreign markets, but also the import threat arising from foreign firms penetrating into the domestic market. These mechanisms affect wage formation and employment creation through many channels...... with imperfect competition, heterogeneity in the labour market, and decentralized wage-bargaining. The Paper analyses how product market integration affects wage formation, and identifies characteristics of winners and losers in the integration process....

Equipment for heating the exhaust gases of internal combustion engines in order to improve afterburning

Energy Technology Data Exchange (ETDEWEB)

Masaki,

1976-04-15

The device described here serves to heat exhaust gases of internal combustion engines by heat exchange with hot gases and also, in cold engines, to raise the temperature of the fuel-air mixture drawn in by the engine. The device is installed next to the outlet opening of the engine. It consists of a burner to generate the hot gas, as well as a heat exchanger permitting heat supply to the exhaust gases and a hot-gas line leading to the intake line. Heating of the air is taken in leads to a better atomization of the mixture and thus to improved combustion. Heating of the exhaust gases improves afterburning. The burner generating the hot gas is shut off when the normal operational temperature of the engine is reached. The temperature is controlled by means of a temperature sensor installed in the device.

Organisational Learning through International M&A Integration Strategies

Science.gov (United States)

Holland, Wayne; Salama, Alzira

2010-01-01

Purpose: The purpose of this research paper is to explore the learning process associated with international mergers and acquisitions (M&A) integration strategies. Design/methodology/approach: The paper employs a comparative case study methodology, utilising qualitative data through in-depth interviews with top management responsible for…

Thermal mechanical analysis of applications with internal heat generation

Science.gov (United States)

Govindarajan, Srisharan Garg

The radioactive tracer Technetium-99m is widely used in medical imaging and is derived from its parent isotope Molybedenum-99 (Mo-99) by radioactive decay. The majority of Molybdenum-99 (Mo-99) produced internationally is extracted from high enriched uranium (HEU) dispersion targets that have been irradiated. To alleviate proliferation risks associated with HEU-based targets, the use of non-HEU sources is being mandated. However, the conversion of HEU to LEU based dispersion targets affects the Mo-99 available for chemical extraction. A possible approach to increase the uranium density, to recover the loss in Mo-99 production-per-target, is to use an LEU metal foil placed within an aluminum cladding to form a composite structure. The target is expected to contain the fission products and to dissipate the generated heat to the reactor coolant. In the event of interfacial separation, an increase in the thermal resistance could lead to an unacceptable rise in the LEU temperature and stresses in the target. The target can be deemed structurally safe as long as the thermally induced stresses are within the yield strength of the cladding and welds. As with the thermal and structural safety of the annular target, the thermally induced deflection of the BORALRTM-based control blades, used by the University of Missouri Research Reactor (MURRRTM ), during reactor operation has been analyzed. The boron, which is the neutron absorber in BORAL, and aluminum mixture (BORAL meat) and the aluminum cladding are bonded together through powder metallurgy to establish an adherent bonded plate. As the BORAL absorbs both neutron particles and gamma rays, there is volumetric heat generation and a corresponding rise in temperature. Since the BORAL meat and aluminum cladding materials have different thermal expansion coefficients, the blade may have a tendency to deform as the blade temperature changes and the materials expand at different rates. In addition to the composite nature of the

A three-region conduction-controlled rewetting analysis by the Heat Balance Integral Method

International Nuclear Information System (INIS)

Sahu, S.K.; Das, P.K.; Bhattacharyya, S.

2009-01-01

Conduction-controlled rewetting of two-dimensional objects is analyzed by the Heat Balance Integral Method (HBIM) considering three distinct regions: a dry region ahead of wet front, the sputtering region immediately behind the wet front and a continuous film region further upstream. The HBIM yields solutions for wet front velocity, sputtering length and temperature field with respect to wet front. Employing this method, it is seen that heat transfer mechanism is dependent upon two temperature parameters. One of them characterizes the initial wall temperature while the other specifies the range of temperature for sputtering region. Additionally, the mechanism of heat transfer is found to be dependent on two Biot numbers comprising a convective heat transfer in the wet region and a boiling heat transfer in the sputtering region. The present solution exactly matches with the one-dimensional analysis of K.H. Sun, G.E. Dix, C.L. Tien [Cooling of a very hot vertical surface by falling liquid film, ASME J. Heat Transf. 96 (1974) 126-131] for low Biot numbers. Good agreement with experimental results is also observed. (authors)

Metallic materials for heat exchanger components and highly stressed internal of HTR reactors for nuclear process heat generation

International Nuclear Information System (INIS)

1982-01-01

The programme was aimed at the development and improvement of materials for the high-temperature heat exchanger components of a process steam HTR. The materials must have high resistance to corrosion, i.e. carburisation and internal oxidation, and high long-term toughness over a wide range of temperatures. They must also meet the requirements set in the nuclear licensing procedure, i.e. resistance to cyclic stress and irradiation, non-destructive testing, etc. Initially, it was only intended to improve and qualify commercial alloys. Later on an alloy development programme was initiated in which new, non-commercial alloys were produced and modified for use in a nuclear process heat facility. Separate abstracts were prepared for 19 pays of this volume. (orig./IHOE) [de

Integral method for transient He II heat transfer in a semi-infinite domain

Science.gov (United States)

Baudouy, B.

2002-05-01

Integral methods are suited to solve a non-linear system of differential equations where the non-linearity can be found either in the differential equations or in the boundary conditions. Though they are approximate methods, they have proven to give simple solutions with acceptable accuracy for transient heat transfer in He II. Taking in account the temperature dependence of thermal properties, direct solutions are found without the need of adjusting a parameter. Previously, we have presented a solution for the clamped heat flux and in the present study this method is used to accommodate the clamped-temperature problem. In the case of constant thermal properties, this method yields results that are within a few percent of the exact solution for the heat flux at the axis origin. We applied this solution to analyze recovery from burnout and find an agreement within 10% at low heat flux, whereas at high heat flux the model deviates from the experimental data suggesting the need for a more refined thermal model.

Integral method for transient He II heat transfer in a semi-infinite domain

International Nuclear Information System (INIS)

Baudouy, B.

2002-01-01

Integral methods are suited to solve a non-linear system of differential equations where the non-linearity can be found either in the differential equations or in the boundary conditions. Though they are approximate methods, they have proven to give simple solutions with acceptable accuracy for transient heat transfer in He II. Taking in account the temperature dependence of thermal properties, direct solutions are found without the need of adjusting a parameter. Previously, we have presented a solution for the clamped heat flux and in the present study this method is used to accommodate the clamped-temperature problem. In the case of constant thermal properties, this method yields results that are within a few percent of the exact solution for the heat flux at the axis origin. We applied this solution to analyze recovery from burnout and find an agreement within 10% at low heat flux, whereas at high heat flux the model deviates from the experimental data suggesting the need for a more refined thermal model

Simulation Tests in Whole Building Heat and Moisture Transfer

DEFF Research Database (Denmark)

Rode, Carsten; Peuhkuri, Ruut Hannele; Woloszyn, Monika

2006-01-01

An important part of the International Energy Agency project, ECBCS, Annex 41 is about modelling the integral heat, air and moisture transfer processes that take place in “whole buildings”. Such modelling deals with all most relevant elements of buildings: The indoor air, the building envelope...

Performance investigation on a 4-bed adsorption desalination cycle with internal heat recovery scheme

KAUST Repository

Thu, Kyaw; Yanagi, Hideharu; Saha, Bidyut Baran; Ng, Kim Choon

2016-01-01

Multi-bed adsorption cycle with the internal heat recovery between the condenser and the evaporator is investigated for desalination application. A numerical model is developed for a 4-bed adsorption cycle implemented with the master

Air-Source Integrated Heat Pump System Development – Final Report

Energy Technology Data Exchange (ETDEWEB)

Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ally, Moonis R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Uselton, R. B. [Lennox Industries, Inc., Knoxville, TN (United States)

2017-07-01

Between October 2007 and September 2017, Oak Ridge National Laboratory (ORNL) and Lennox Industries, Inc. (Lennox) engaged in a Cooperative Research and Development Agreement (CRADA) to develop an air-source integrated heat pump (AS-IHP) system for the US residential market. The Lennox AS-IHP concept consisted of a high-efficiency air-source heat pump (ASHP) for space heating and cooling services and a separate heat pump water heater/dehumidifier (WH/DH) module for domestic water heating and dehumidification (DH) services. A key feature of this system approach with the separate WH/DH is capability to pretreat (i.e., dehumidify) ventilation air and dedicated whole-house DH independent of the ASHP. Two generations of laboratory prototype WH/DH units were designed, fabricated, and lab tested. Performance maps for the system were developed using the latest research version of the US Department of Energy/ORNL heat pump design model (Rice 1992; Rice and Jackson 2005; Shen et al. 2012) as calibrated against the lab test data. These maps served as the input to TRNSYS (Solar Energy Laboratory et al. 2010) to predict annual performance relative to a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (i.e., a combination of an ASHP with a seasonal energy efficiency ratio (SEER) of 13 and resistance water heater with an energy factor (EF) of 0.9). Predicted total annual energy savings (based on use of a two-speed ASHP and the second-generation WH/DH prototype for the AS-IHP), while providing space conditioning, water heating, and dehumidification for a tight, well-insulated 2600 ft2 (242 m2) house at three US locations, ranged from 33 to 36%, averaging 35%, relative to the baseline system. The lowest savings were seen at the cold-climate Chicago location. Predicted energy use for water heating was reduced by about 50 to 60% relative to a resistance WH.

Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

OpenAIRE

Aladayleh, Wail; Alahmer, Ali

2015-01-01

This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively....

Influence of individual heat pumps on wind power integration – Energy system investments and operation

DEFF Research Database (Denmark)

Hedegaard, Karsten; Münster, Marie

2013-01-01

Individual heat pumps are expected to constitute a significant electricity demand in future energy systems. This demand becomes flexible if investing in complementing heat storage capabilities. In this study, we analyse how the heat pumps can influence the integration of wind power by applying...... an energy system model that optimises both investments and operation, and covers various heat storage options. The Danish energy system by 2030 with around 50–60% wind power is used as a case study. Results show that the heat pumps, even without flexible operation, can contribute significantly...... to facilitating larger wind power investments and reducing system costs, fuel consumption, and CO2 emissions. Investments in heat storages can provide only moderate system benefits in these respects. The main benefit of the flexible heat pump operation is a reduced need for peak/reserve capacity, which is also...

Comparison of Marginal and Internal Adaptation of Heat-Pressed and CAD/CAM Porcelain Laminate Veneers and a 2-Year Follow-Up.

Science.gov (United States)

Yuce, Mert; Ulusoy, Mubin; Turk, Ayse Gozde

2017-12-22

To compare marginal and internal adaptations of porcelain laminate veneers fabricated with heat-pressed and CAD/CAM techniques, and to evaluate the clinical performances 2 years after cementation. Thirty heat-pressed and 31 CAD/CAM porcelain laminate veneers were fabricated for 12 patients. Silicone replicas of each veneer were obtained. Replicas were sectioned into 4 parts to measure adaptations of the veneers. A stereomicroscope was used to measure from 3 locations of replicas for marginal, and 9 locations for internal adaptations at 40x magnification. Clinical evaluations were done at baseline and 6, 12, 18, and 24 months after cementation according to the modified United States Public Health Service (USPHS) criteria. Independent samples t-test compared the adaptation values between heat-pressed and CAD/CAM groups. Paired t-test was used to evaluate marginal and internal adaptations of each group. Differences between the modified USPHS criteria ratings of heat-pressed and CAD/CAM groups were determined by the Mann-Whitney U test. Kaplan-Meier analysis was used to analyze the survival ratings of the veneers (p CAD/CAM veneers were 295 and 314.98 μm, respectively, and there was no statistically significant difference (p = 0.541). Internal adaptation values of groups were not statistically different either (201.82 μm for heat pressed; 195.47 μm for CAD/CAM p = 0.734). When marginal and internal adaptation values were compared within groups, there were significant differences both for heat-pressed (p CAD/CAM (p CAD/CAM or heat-pressed, had no effect on the marginal and internal adaptation of porcelain laminate veneers. The results showed that both fabrication techniques performed well after 2 years of clinical performance. © 2017 by the American College of Prosthodontists.

Observing integrals of heat kernels from a distance

DEFF Research Database (Denmark)

Heat kernels have integrals such as Brownian motion mean exit time, potential capacity, and torsional rigidity. We show how to obtain bounds on these values - essentially by observing their behaviour in terms of the distance function from a point and then comparing with corresponding values in ta...... and discussed as test cases. The talk is based on joint work with Vicente Palmer....... in tailor-made warped product spaces. The results will be illustrated by applications to the so-called 'type' problem: How to decide if a given manifold or surface is transient (hyperbolic) or recurrent (parabolic). Specific examples of minimal surfaces and constant pressure dry foams will be shown...

Can Integration of Agriculture With International Trade Increase ...

African Journals Online (AJOL)

Human activity is greatly constituted by transactions and exchange that can impoverish primary producers while unfairly making others rich in an inequitable manner. Integration of agriculture into international trade is always thought and assumed to bring greater income benefit to farmers, but is this really the case, ...

Natural convection heat transfer in SIGMA experiment

International Nuclear Information System (INIS)

Lee, Seung Dong; Lee, Gang Hee; Suh, Kune Yull

2004-01-01

A loss-of-coolant accident (LOCA) results in core melt formation and relocation at various locations within the reactor core over a considerable period of time. If there is no effective cooling mechanism, the core debris may heat up and commence natural circulation. The high temperature pool of molten core material will threaten the structural integrity of the reactor vessel. The extent and urgency of this threat depend primarily upon the intensity of the internal heat sources and upon the consequent distribution of the heat fluxes on the vessel walls in contact with the molten core material pools. In such a steady molten pool convection state, the thermal loads against the vessel would be determined by the in-vessel heat transfer distribution involving convective and conductive heat transfer from the decay-heated core material pool to the lower head wall in contact with the core material. In this study, upward and downward heat transfer fraction ratio is focused on

Controlling the Internal Heat Transfer Coefficient by the Characteristics of External Flows

Science.gov (United States)

Zhuromskii, V. M.

2018-01-01

The engineering-physical fundamentals of substance synthesis in a boiling apparatus are presented. We have modeled a system of automatic stabilization of the maximum internal heat transfer coefficient in such an apparatus by the characteristics of external flows on the basis of adaptive seeking algorithms. The results of operation of the system in the shop are presented.

Workplace Integration: Key Considerations for Internationally Educated Nurses and Employers

OpenAIRE

Zubeida Ramji; Josephine Etowa

2018-01-01

Integration of internationally educated nurses (IENs) in the workplace over the long term, has not been a clear focus in nursing. The role of the employer organization in facilitating workplace integration for IENs has also not been emphasized in research. The overall aim of this paper is to highlight findings from an instrumental qualitative case study research informed by critical social theory, which examined workplace integration of IENs. The study explored what is meant by ‘integration’ ...

ROLE OF INTERNATIONAL MERGERS AND ACQUISITIONS IN CORPORATE INTEGRATION

OpenAIRE

Lucia P. BLĂJUȚ

2015-01-01

This paper highlights the role of international mergers and acquisitions in corporate integration. The factors that stimulate mergers and acquisitions activities bring real changes in the world economy. Mergers and acquisitions are a form of expansion: mergers can take place either as a statutory merger or consolidation and minority, majority or full acquisitions dominate the international market. It is very important to not confuse the meaning of the two terms. Multinational companies are fo...

Thermal resistance of rotating closed-loop pulsating heat pipes: Effects of working fluids and internal diameters

Directory of Open Access Journals (Sweden)

Kammuang-Lue Niti

2017-01-01

Full Text Available The objective of this study was to experimentally investigate the effects of working fluids and internal diameters on the thermal resistance of rotating closed-loop pul¬sating heat pipes (RCLPHP. The RCLPHP were made of a copper tube with internal diameters of 1.50 mm and 1.78 mm, bent into the shape of a flower petal, and arranged into a circle with 11 turns. The evaporator section was located at the outer end of the tube bundle. R123, ethanol, and water were filled as the working fluids. The RCLPHP was rotated at centrifugal accelerations 0.5, 1, 3, 5, 10, and 20 times of the gravitational acceleration considered at the connection between the evaporator and the condenser sections. The heat input was varied from 30 W to 50 W, and then to 100 W, 150 W, and 200 W. It can be concluded that when the latent heat of evaporation increases, the pressure difference between the evaporator and the condenser sections decreases, and the thermal resistance increases. Moreover, when the internal diameter increases, the driving force increases and the frictional force proportionally decreases, or the Karman number increases, and the thermal resistance decreases.

Results of out-of-pile experiments to investigate the possibilities of cooling a core melt with internal heat production

International Nuclear Information System (INIS)

Fieg, G.

1976-01-01

After serious hypothetical reactor accidents, melted core materials with internal heat production can occur in large quantities. A retention of these molten core masses within the containment must be ensured. The knowledge of the heat transport from volume-heated layers is necessary to clarify this matter. (orig./LH) [de

Calculating the heat transfer coefficient of frame profiles with internal cavities

DEFF Research Database (Denmark)

Noyé, Peter Anders; Laustsen, Jacob Birck; Svendsen, Svend

2004-01-01

. The heat transfer coefficient is determined by two-dimensional numerical calculations and by measurements. Calculations are performed in Therm (LBNL (2001)), which is developed at Lawrence Berkeley National Laboratory, USA. The calculations are performed in accordance with the future European standards...... correspondence between measured and calculated values. Hence, when determining the heat transfer coefficient of frame profiles with internal cavities by calculations, it is necessary to apply a more detailed radiation exchange model than described in the prEN ISO 10077-2 standard. The ISO-standard offers......Determining the energy performance of windows requires detailed knowledge of the thermal properties of their different elements. A series of standards and guidelines exist in this area. The thermal properties of the frame can be determined either by detailed two-dimensional numerical methods...

Proceedings of the third international steam generator and heat exchanger conference

International Nuclear Information System (INIS)

1998-01-01

The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas, including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues

Proceedings of the third international steam generator and heat exchanger conference

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-07-01

The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas,including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues.

From Modules to a Generator: An Integrated Heat Exchanger Concept for Car Applications of a Thermoelectric Generator

Science.gov (United States)

Bosch, Henry

2016-03-01

A heat exchanger concept for a thermoelectric generator with integrated planar modules for passenger car applications is introduced. The module housings, made of deep drawn stainless steel sheet metal, are brazed onto the exhaust gas channel to achieve an optimal heat transfer on the hot side of the modules. The cooling side consists of winding fluid channels, which are mounted directly onto the cold side of the modules. Only a thin foil separates the cooling media from the modules for an almost direct heat contact on the cooling side. Thermoelectric generators with up to 20 modules made of PbTe and Bi2Te3, respectively, are manufactured and tested on a hot gas generator to investigate electrical power output and performance of the thermoelectric generator. The proof of concept of the light weight heat exchanger design made of sheet metal with integrated modules is positively accomplished.

Temperature and heat flux scaling laws for isoviscous, infinite Prandtl number mixed heating convection.

Science.gov (United States)

Vilella, Kenny; Deschamps, Frederic

2018-04-01

Thermal evolution of terrestrial planets is controlled by heat transfer through their silicate mantles. A suitable framework for modelling this heat transport is a system including bottom heating (from the core) and internal heating, e.g., generated by secular cooling or by the decay of radioactive isotopes. The mechanism of heat transfer depends on the physical properties of the system. In systems where convection is able to operate, two different regimes are possible depending on the relative amount of bottom and internal heating. For moderate internal heating rates, the system is composed of active hot upwellings and cold downwellings. For large internal heating rates, the bottom heat flux becomes negative and the system is only composed of active cold downwellings. Here, we build theoretical scaling laws for both convective regimes following the approach of Vilella & Kaminski (2017), which links the surface heat flux and the temperature jump across both the top and bottom thermal boundary layer (TBL) to the Rayleigh number and the dimensionless internal heating rate. Theoretical predictions are then verified against numerical simulations performed in 2D and 3D-Cartesian geometry, and covering a large range of the parameter space. Our theoretical scaling laws are more successful in predicting the thermal structure of systems with large internal heating rates than that of systems with no or moderate internal heating. The differences between moderate and large internal heating rates are interpreted as differences in the mechanisms generating thermal instabilities. We identified three mechanisms: conductive growth of the TBL, instability impacting, and TBL erosion, the last two being present only for moderate internal heating rates, in which hot plumes are generated at the bottom of the system and are able to reach the surface. Finally, we apply our scaling laws to the evolution of the early Earth, proposing a new model for the cooling of the primordial magma ocean

A dynamic model and an experimental study for the internal air and soil temperatures in an innovative greenhouse

International Nuclear Information System (INIS)

Joudi, Khalid A.; Farhan, Ammar A.

2015-01-01

Highlights: • Simulation model for internal Greenhouse temperature including soil reflectance. • Greenhouse soil heat exchange affects internal temperature by approximately 12%. • Solar air heaters as greenhouse roof maintain better internal temperature year round. - Abstract: An innovative greenhouse which integrates a conventional greenhouse with roof mounted solar air heaters is used in this investigation. This design reduces the solar radiation incoming to the greenhouse in summer which reduced the load and cost of greenhouse cooling and provides a means of solar heating. Experimental measurements of the internal air and internal soil sub-layer temperatures in the greenhouse, without crops, were performed in Baghdad University, Baghdad, Iraq (33.3 °N, 44.4 °E). Measurements were recorded for clear and partly cloudy winter days. A dynamic model was developed to predict the all internal temperatures of the greenhouse. This model includes soil surface heat exchange with the greenhouse air which was found to give a more accurate prediction of the internal temperatures. Soil surface heat exchange has a positive contribution to the internal environment. The input parameters of the model were the measured meteorological conditions and the thermo-physical properties of the greenhouse components which include the cover, inside air, and soil. Comparisons between the predicted and measured results show good agreement. Also, results show that soil sub-layers inside the greenhouse at 50 cm depth are the best place for heat storage elements. The integrated system rendered maximum differences between ambient and internal air temperatures of 16 °C in February and 10 °C in June without operating any heating or cooling system

Trends of International Trade in Services: Integration Opportunities for Ukraine

Directory of Open Access Journals (Sweden)

Tetyana Bodnarchuk

2017-12-01

Full Text Available In the article the main trends and patterns of the development of international trade in services in the period of post-industrial development of the world economy are considered. Ukraine’s competitive positions on international service market are outlined. The main endogenous factors of enhancing the country’s integration to the world trade relations system in service sector are determined.

Simulation and experimental study of solar-absorption heat transformer integrating with two-stage high temperature vapor compression heat pump

Directory of Open Access Journals (Sweden)

Nattaporn Chaiyat

2014-11-01

Full Text Available In this study, simulation and experiment studies of a 10 kW solar H2O–LiBr absorption heat transformer (AHT integrating with a two-stage vapor compression heat pump (VCHP were carried out. The whole system was named as compression/absorption heat transformer (CAHT. The VCHP was used to recover rejected heat at the AHT condenser which was transferred back to the AHT evaporator at a higher temperature. The AHT unit took solar heat from a set of flat-plate solar collectors in parallel connection. R-134a and R-123 were refrigerants in the VCHP cycle. From the simulation, the total cycle coefficient (COP of the solar-CAHT was 0.71 compared with 0.49 of the normal solar-AHT. From the experiment, the total cycle COPs of the solar-CAHT and the solar-AHT were 0.62 and 0.39, respectively. The experimental results were lower than those of the simulated models due to the oversize of the experimental compressor. The annual expense of the solar-CAHT was found to be 5113 USD which was lower than 5418 USD of the solar-AHT. So it could be concluded that the modified unit was beneficial than the normal unit in terms of energy efficiency and economic expense.

Modeling the integration of thermoelectrics in anode exhaust combustors for waste heat recovery in fuel cell systems

Science.gov (United States)

Maghdouri Moghaddam, Anita

Recently developed small-scale hydrocarbon-fueled fuel cell systems for portable power under 1 kW have overall system efficiencies typically no higher than 30-35%. This study explores the possibility of using of thermoelectric waste heat recovery in anode exhaust combustors to improve the fuel cell system efficiencies by as much as 4-5% points and further to reduce required battery power during system start-up. Two models were used to explore this. The first model simulated an integrated SOFC system with a simplified catalytic combustor model with TEs integrated between the combustor and air preheating channels for waste heat recovery. This model provided the basis for assessing how much additional power can achieve during SOFC operation as a function of fuel cell operating conditions. Results for the SOFC system indicate that while the TEs may recover as much as 4% of the total fuel energy into the system, their benefit is reduced in part because they reduce the waste heat transferred back to the incoming air stream and thereby lower the SOFC operating temperatures and operating efficiencies. A second model transient model of a TE-integrated catalytic combustor explored the performance of the TEs during transient start-up of the combustor. This model incorporated more detailed catalytic combustion chemistry and enhanced cooling air fin heat transfer to show the dynamic heating of the integrated combustor. This detailed model provided a basis for exploring combustor designs and showed the importance of adequate reactant preheating when burning exhaust from a reformer during start-up for the TEs to produce significant power to reduce the size of system batteries for start-up.

Design and Implementation of a Discrete-Time Proportional Integral (PI) Controller for the Temperature Control of a Heating Pad.

Science.gov (United States)

Khan, Pathan Fayaz; Sengottuvel, S; Patel, Rajesh; Gireesan, K; Baskaran, R; Mani, Awadhesh

2018-05-01

Contact heat evoked potentials (CHEPs) are recorded from the brain by giving thermal stimulations through heating pads kept on the surface of the skin. CHEP signals have crucial diagnostic implications in human pain activation studies. This work proposes a novel design of a digital proportional integral (PI) controller based on Arduino microcontroller with a view to explore the suitability of an electric heating pad for use as a thermode in a custom-made, cost-effective CHEP stimulator. The purpose of PI controller is to set, regulate, and deliver desired temperatures on the surface of the heating pad in a user-defined pattern. The transfer function of the heating system has been deduced using the parametric system identification method, and the design parameters of the controller have been identified using the root locus technique. The efficiency of the proposed PI controller in circumventing the well-known integrator windup problem (error in the integral term builds excessively, leading to large transients in the controller output) in tracking the reference input and the controller effort (CE) in rejecting output disturbances to maintain the set temperature of the heating pad have been found to be superior compared with the conventional PI controller and two of the existing anti-windup models.

The International Heat Stress Genotype Experiment for modeling wheat response to heat: field experiments and AgMIP-Wheat multi-model simulations

DEFF Research Database (Denmark)

Martre, Pierre; Reynolds, Matthew; Asseng, Senthold

2017-01-01

The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown...... dates. Data include local daily weather data, soil characteristics and initial soil conditions, crop measurements (anthesis and maturity dates, anthesis and final total above ground biomass, final grain yields and yields components), and cultivar information. Simulations include both daily in-season...... and end-of-season results from 30 wheat models....

Reduced anterior internal capsule white matter integrity in primary insomnia.

Science.gov (United States)

Spiegelhalder, Kai; Regen, Wolfram; Prem, Martin; Baglioni, Chiara; Nissen, Christoph; Feige, Bernd; Schnell, Susanne; Kiselev, Valerij G; Hennig, Jürgen; Riemann, Dieter

2014-07-01

Chronic insomnia is one of the most prevalent central nervous system diseases, however, its neurobiology is poorly understood. Up to now, nothing is known about the integrity of white matter tracts in insomnia patients. In this study, diffusion tensor imaging (DTI) was used in a well-characterized sample of primary insomnia (PI) patients and good sleeper controls to fill this void. Voxelwise between-group comparisons of fractional anisotropy (FA) were performed in 24 PI patients (10 males; 14 females; 42.7 ± 14.5 years) and 35 healthy good sleepers (15 males; 20 females; 40.1 ± 9.1 years) with age and sex as covariates. PI patients showed reduced FA values within the right anterior internal capsule and a trend for reduced FA values in the left anterior internal capsule. The results suggest that insomnia is associated with a reduced integrity of white matter tracts in the anterior internal capsule indicating that disturbed fronto-subcortical connectivity may be a cause or consequence of the disorder.

Energetic and Exergetic Analysis of Low and Medium Temperature District Heating Network Integration

DEFF Research Database (Denmark)

Li, Hongwei; Svendsen, Svend

In this paper, energetic and exergetic approaches were applied to an exemplary low temperature district heating (LTDH) network with supply/return water temperature at 55oC/25 oC. The small LTDH network is annexed to a large medium temperature district heating (MTDH) network. The LTDH network can ...... will reduce the amount of water supply from the MTDH network and improve the system energy conversion efficiency. Through the simulation, the system energetic and exergetic efficiencies based on the two network integration approaches were calculated and evaluated.......In this paper, energetic and exergetic approaches were applied to an exemplary low temperature district heating (LTDH) network with supply/return water temperature at 55oC/25 oC. The small LTDH network is annexed to a large medium temperature district heating (MTDH) network. The LTDH network can...... be supplied through upgrading the return water from the MTDH network with a small centralized heat pump. Alternatively, the supply and return water from the MTDH network can be mixed with a shunt at the junction point to supply the LTDH network. Comparing with the second approach, the heat pump system...

Potentialities and type of integrating nuclear heating stations into district heating systems

International Nuclear Information System (INIS)

Munser, H.; Reetz, B.; Schmidt, G.

1978-01-01

Technical and economical potentialities of applying nuclear heating stations in district heating systems are discussed considering the conditions of the GDR. Special attention is paid to an optimum combination of nuclear heating stations with heat sources based on organic fuels. Optimum values of the contribution of nuclear heating stations to such combined systems and the economic power range of nuclear heating stations are estimated. Final considerations are concerned with the effect of siting and safety concepts of nuclear heating stations on the structure of the district heating system. (author)

Use of integral experiments to improve neutron propagation and gamma heating calculations

International Nuclear Information System (INIS)

Oceraies, Y.; Caumette, P.; Devillers, C.; Bussac, J.

1979-01-01

1) The studies to define and improve the accuracies of neutron propagation and gamma heating calculations from integral experiments are encompassed in the field of the fast reactor physics program at CEA. 2) A systematic analysis of neutron propagation in Fe-Na clean media, with variable volumic composition between 0 and 100% in sodium, has been performed on the HARMONIE source reactor. Gamma heating traverses in the core, the blankets and several control rods, have been measured in the R Z core program at MASURCA. The experimental techniques, the accuracies and the results obtained are given. The approximations of the calculational methods used to analyse these experiments and to predict the corresponding design parameters are also described. 3) Particular emphasis is given to the methods planned to improve fundamental data used in neutron propagation calculations, using the discrepancies observed between measured and calculated results in clean integral experiments. One of these approaches, similar to the techniques used in core physics, relies upon sensitivity studies and eventually on adjustment techniques applied to neutron propagation. (author)

Integrable systems for particles with internal degrees of freedom

CERN Document Server

Minahan, J A; Minahan, Joseph A.; Polychronakos, Alexios P.

1993-01-01

We show that a class of models for particles with internal degrees of freedom are integrable. These systems are basically generalizations of the models of Calogero and Sutherland. The proofs of integrability are based on a recently developed exchange operator formalism. We calculate the wave-functions for the Calogero-like models and find the ground-state wave-function for a Calogero-like model in a position dependent magnetic field. This last model might have some relevance for matrix models of open strings.

Cold reservoir integrated into a brine circuit of energy roofing, coupled to a heat pump

Energy Technology Data Exchange (ETDEWEB)

Schroeder, M.

1983-12-01

Model studies are presented in which the economic effects of a cold reservoir integrated in a heat pump system were established. Cold reservoirs have the following advantages: 1. The absolute annual savings increase with the storage volume. Storage volumes of 1 to 10 m/sup 3/ are economical, depending on the mode of operation. 2. If the storage volume is sufficiently large, the heat pump (operated in a bivalent, parallel system) can supply a considerable amount of the required even below the design temperature. 3. With a sufficiently large storage volume, the heat pump may be operated in more or less monovalent mode even if the heat pump has not been designed for a minimum ambient temperature.

Solid-State Additive Manufacturing for Heat Exchangers

Science.gov (United States)

Norfolk, Mark; Johnson, Hilary

2015-03-01

Energy densities in devices are increasing across many industries including power generation, high power electronics, manufacturing, and automotive. Increasingly, there is a need for very high efficiency thermal management devices that can pull heat out of a small area at higher and higher rates. Metal additive manufacturing (AM) technologies have the promise of creating parts with complex internal geometries required for integral thermal management. However, this goal has not been met due to constraints in fusion-based metal 3D printers. This work presents a new strategy for metal AM of heat exchangers using an ultrasonic sheet lamination approach.

DOE Heat Pump Centered Integrated Community Energy Systems Project

Energy Technology Data Exchange (ETDEWEB)

Calm, J. M.

1979-01-01

The Heat Pump Centered Integrated Community Energy Systems (HP-ICES) Project is a multiphase undertaking seeking to demonstrate one or more operational HP-ICES by the end of 1983. The seven phases include System Development, Demonstration Design, Design Completion, HP-ICES Construction, Operation and Data Acquisition, HP-ICES Evaluation, and Upgraded Continuation. This project is sponsored by the Community Systems Branch, Office of Buildings and Community Systems, Assistant Secretary for Conservation and Solar Applicaions, U.S. Department of Energy (DOE). It is part of the Community Systems Program and is managed by the Energy and Environmental Systems Division of Argonne Natinal Laboratory.

Structural reasons for vertical integration in the international oil industry

International Nuclear Information System (INIS)

Luciani, G.

1991-01-01

Once upon a time, the international oil industry was vertically integrated. A small group of companies controlled a very substantial share of international oil flows, extending their operations from the oil well to the gas pump, and relying on intracorporate transfers for most in-between transactions. The historical reasons for vertical disintegration, the market role, and structural reasons for vertical reintegration are examined. (author)

Energylab Nordhavn: An integrated community energy system towards green heating and e-mobility

DEFF Research Database (Denmark)

Wang, Jiawei; You, Shi; Zong, Yi

2017-01-01

This paper analyzes the green potential of a newly developed urban community, i.e., Nordhavn, in Copenhagen, Denmark from a planning perspective, wherein the energy sector of power, heat and transportation will be developed as an integrated energy system solution. Based on an hour-by-hour analysi...

Integrating Ethics into International Business Teaching: Challenges and Methodologies in the Greater China Context

Science.gov (United States)

Whitla, Paul

2011-01-01

This paper examines the process of integrating ethics into the teaching of international business within the Greater China region. An example of how ethics is integrated into a required undergraduate international business course at a Hong Kong based university is presented. The contextual challenges of developing a course for use in the Greater…

Incentives and stability of international climate coalitions: An integrated assessment

International Nuclear Information System (INIS)

Bosetti, Valentina; Carraro, Carlo; De Cian, Enrica; Massetti, Emanuele; Tavoni, Massimo

2013-01-01

This paper analyses the incentives to participate in an international climate agreement and the stability of the resulting climate coalition using the integrated assessment model WITCH. Coalition stability is assessed under alternative assumptions concerning the pure rate of time preference, the aggregation of social welfare, and the severity of climate damages. The profitability, stability, and strong potential internal stability of a number of coalitions, those potentially effective in reducing GHG emissions, is explored in the paper. The main conclusion is that only the grand coalition, i.e. a coalition where all world regions cooperate to reduce emissions, can maintain GHG concentration below 550 ppm CO 2 -eq. However, this coalition is not internally stable, even when allowing for monetary transfers across world regions. Nonetheless, the paper also shows that strongly potentially internally stable coalitions exist, though of smaller size, which can mitigate global warming and limit GHG concentrations to 600 ppm CO 2 -eq. - Highlights: ► We analyse climate coalitions with an integrated assessment model. ► Coalitions’ profitability and stability is analysed under alternative assumptions. ► Effective coalitions should include larger emitters (such as India and China). ► A coalition that achieves 550 ppm CO 2 -eq is not internally stable. ► A stable coalition can achieve around 518 ppme in 2050 and 600 ppme in 2100

Review of organic Rankine cycles for internal combustion engine exhaust waste heat recovery

International Nuclear Information System (INIS)

Sprouse, Charles; Depcik, Christopher

2013-01-01

Escalating fuel prices and future carbon dioxide emission limits are creating a renewed interest in methods to increase the thermal efficiency of engines beyond the limit of in-cylinder techniques. One promising mechanism that accomplishes both objectives is the conversion of engine waste heat to a more useful form of energy, either mechanical or electrical. This paper reviews the history of internal combustion engine exhaust waste heat recovery focusing on Organic Rankine Cycles since this thermodynamic cycle works well with the medium-grade energy of the exhaust. Selection of the cycle expander and working fluid are the primary focus of the review, since they are regarded as having the largest impact on system performance. Results demonstrate a potential fuel economy improvement around 10% with modern refrigerants and advancements in expander technology. -- Highlights: ► This review article focuses on engine exhaust waste heat recovery works. ► The organic Rankine cycle is superior for low to medium exergy heat sources. ► Working fluid and expander selection strongly influence efficiency. ► Several authors demonstrate viable systems for vehicle installation

Integrating Waste Heat from CO₂ Removal and Coal-Fired Flue Gas to Increase Plant Efficiency

Energy Technology Data Exchange (ETDEWEB)

Irvin, Nick [Southern Company Services, Inc., Birmingham, AL (United States); Kowalczyk, Joseph [Southern Company Services, Inc., Birmingham, AL (United States)

2017-04-01

In project DE-FE0007525, Southern Company Services demonstrated heat integration methods for the capture and sequestration of carbon dioxide produced from pulverized coal combustion. A waste heat recovery technology (termed High Efficiency System) from Mitsubishi Heavy Industries America was integrated into an existing 25-MW amine-based CO₂ capture process (Kansai Mitsubishi Carbon Dioxide Recovery Process®1) at Southern Company’s Plant Barry to evaluate improvements in the energy performance of the pulverized coal plant and CO₂ capture process. The heat integration system consists of two primary pieces of equipment: (1) the CO₂ Cooler which uses product CO₂ gas from the capture process to heat boiler condensate, and (2) the Flue Gas Cooler which uses air heater outlet flue gas to further heat boiler condensate. Both pieces of equipment were included in the pilot system. The pilot CO₂ Cooler used waste heat from the 25-MW CO₂ capture plant (but not always from product CO₂ gas, as intended). The pilot Flue Gas Cooler used heat from a slipstream of flue gas taken from downstream of Plant Barry’s air heater. The pilot also included a 0.25-MW electrostatic precipitator. The 25-MW High Efficiency System operated for approximately six weeks over a four month time period in conjunction with the 25-MW CO₂ capture facility at Plant Barry. Results from the program were used to evaluate the technical and economic feasibility of full-scale implementation of this technology. The test program quantified energy efficiency improvements to a host power plant that could be realized due to the High Efficiency System. Through the execution of this project, the team verified the integrated operation of the High Efficiency System and Kansai Mitsubishi Carbon Dioxide Recovery Process®. The ancillary benefits of the High Efficiency System were also quantified, including reduced water consumption

New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

International Nuclear Information System (INIS)

Qu, Ming; Abdelaziz, Omar; Yin, Hongxi

2014-01-01

Highlights: • Thermal and heat transfer models of absorption heat pumps driven by exhaust gas, hot water, or natural gas. • Natural gas boiler combustion model. • Heat exchanger for condensing. • Experimental data of a hot water absorption heat pump. • Economic assessment of heat recovery absorption heat pump for improving natural gas boilers. - Abstract: Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150–200 °C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50–60 °C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural

Development of an integrated heat pipe-thermal storage system for a solar receiver

Science.gov (United States)

Keddy, E. S.; Sena, J. T.; Merrigan, M. A.; Heidenreich, G.; Johnson, S.

1987-01-01

The Organic Rankine Cycle (ORC) Solar Dynamic Power System (SDPS) is one of the candidates for Space Station prime power application. In the low Earth orbit of the Space Station approximately 34 minutes of the 94-minute orbital period is spent in eclipse with no solar energy input to the power system. For this period the SDPS will use thermal energy storage (TES) material to provide a constant power output. An integrated heat-pipe thermal storage receiver system is being developed as part of the ORC-SDPS solar receiver. This system incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain the TES canisters within the potassium vapor space with the toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the Earth orbit, solar energy is delivered to the heat pipe in the ORC-SDPS receiver cavity. The heat pipe transforms the non-uniform solar flux incident in the heat pipe surface within the receiver cavity to an essentially uniform flux at the potassium vapor condensation interface in the heat pipe. During solar insolation, part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the balance stored in the TES units is transferred by the potassium vapor to the toluene heater tube.

Development of an integrated heat pipe-thermal storage system for a solar receiver

Science.gov (United States)

Keddy, E. S.; Sena, J. T.; Merrigan, M. A.; Heidenreich, G.; Johnson, S.

1987-07-01

The Organic Rankine Cycle (ORC) Solar Dynamic Power System (SDPS) is one of the candidates for Space Station prime power application. In the low Earth orbit of the Space Station approximately 34 minutes of the 94-minute orbital period is spent in eclipse with no solar energy input to the power system. For this period the SDPS will use thermal energy storage (TES) material to provide a constant power output. An integrated heat-pipe thermal storage receiver system is being developed as part of the ORC-SDPS solar receiver. This system incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain the TES canisters within the potassium vapor space with the toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the Earth orbit, solar energy is delivered to the heat pipe in the ORC-SDPS receiver cavity. The heat pipe transforms the non-uniform solar flux incident in the heat pipe surface within the receiver cavity to an essentially uniform flux at the potassium vapor condensation interface in the heat pipe. During solar insolation, part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the balance stored in the TES units is transferred by the potassium vapor to the toluene heater tube.

Moderator behaviour and reactor internals integrity at Atucha I NPP

International Nuclear Information System (INIS)

Berra, S.; Guala, M.; Herzovich, P.; Chocron, M.; Lorenzo, A.; Raffo Calderon, Ma. C. del; Urrutia, G.

1996-01-01

Atucha I is a Pressure Vessel Heavy Water Cooled Heavy Water Moderator Reactor. In this kind of reactor the moderator tank is physically connected to the primary coolant. Since neutron economy requires the moderator to be as cold as possible, it is necessary that even when physically connected, it should have a separated cooling system, which in this case is also used as a feed-water preheater, and also heat mass transfer with primary coolant should be minimized. This condition requires that some reactor internals are designed in principle to last the whole life of the plant. However, in 1988 the failure of one internal produced a 16 month shut down. This incident could have been prevented but the idea that reactor internals would not have failures due to aging was dominant at that time avoiding the early detection of the failure. However, the analysis of the records after the incident showed that some process variables had changed previously to the incident, i.e., power exchanged at the moderator heat exchanger had increased. Since the station restart up some changes in the moderator process variables and a flow rate reduction of about 10% through the primary side of one moderator cooler were observed. In order to understand the flow reduction and the overall behaviour of moderators parameters, two models were developed that predict moderator and moderator cooler behavior under the new conditions. The present paper refers to these models, which together with the improvement of process variables measurements mentioned in another paper presented at this meeting permits to understand current moderator behaviour and helps to early diagnostic of an eventual reactor internal failure. (author). 2 refs, 4 figs, 1 tab

Moderator behaviour and reactor internals integrity at Atucha I NPP

Energy Technology Data Exchange (ETDEWEB)

Berra, S; Guala, M; Herzovich, P [Central Nuclear Atucha I, Nucleoelectrica Argentina, Lima, Buenos Aires (Argentina); Chocron, M; Lorenzo, A; Raffo Calderon, Ma. C. del; Urrutia, G [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Constituyentes

1997-12-31

Atucha I is a Pressure Vessel Heavy Water Cooled Heavy Water Moderator Reactor. In this kind of reactor the moderator tank is physically connected to the primary coolant. Since neutron economy requires the moderator to be as cold as possible, it is necessary that even when physically connected, it should have a separated cooling system, which in this case is also used as a feed-water preheater, and also heat mass transfer with primary coolant should be minimized. This condition requires that some reactor internals are designed in principle to last the whole life of the plant. However, in 1988 the failure of one internal produced a 16 month shut down. This incident could have been prevented but the idea that reactor internals would not have failures due to aging was dominant at that time avoiding the early detection of the failure. However, the analysis of the records after the incident showed that some process variables had changed previously to the incident, i.e., power exchanged at the moderator heat exchanger had increased. Since the station restart up some changes in the moderator process variables and a flow rate reduction of about 10% through the primary side of one moderator cooler were observed. In order to understand the flow reduction and the overall behaviour of moderators parameters, two models were developed that predict moderator and moderator cooler behavior under the new conditions. The present paper refers to these models, which together with the improvement of process variables measurements mentioned in another paper presented at this meeting permits to understand current moderator behaviour and helps to early diagnostic of an eventual reactor internal failure. (author). 2 refs, 4 figs, 1 tab.

Waste heat recovery systems for internal combustion engines: classification and benefits

OpenAIRE

Marchenko, A.; Samoilenko, D.; Adel Hamzah, Ali; Adel Hamzah, Omar

2014-01-01

Recent trend about the best ways of using the deployable sources of energy in to useful work in order to reduce the rate of consumption of fossil fuel as well as pollution. Out of all the available sources, the internal combustion engines are the major consumer of fossil fuel around the globe. The remaining heat is expelled to the environment through exhaust gases and engine cooling systems, resulting in to entropy rise and serious environmental pollution, so it is required to utilized waste ...

Study of heat removal by natural convection from the internal core catcher in PFBR using water model experiments

International Nuclear Information System (INIS)

Jasmin Sudha, A.; Punitha, G.; Das, S.K.; Lydia, G.; Murthy, S.S.; Malarvizhi, B.; Harvey, J.; Kannan, S.E.

2005-01-01

Full text of publication follows: In the event of a core meltdown accident in a Fast Breeder Reactor, the molten core material settling on the bottom of the main vessel can endanger the structural integrity of the main vessel. In the design of Prototype Fast Breeder Reactor in India, the construction of which is about to commence, a core catcher is provided as the internal core retention device to collect and retain the core debris in a coolable configuration. Heat transfer by natural convection above and below the core catcher plate, in the zone beneath the core support structure is evaluated from water mockup experiments in the 1:4 geometrically scaled setup. These studies were undertaken towards comparison of experimentally measured temperatures at different locations with the numerical results. The core catcher assembly consists of a core catcher plate, a heat shield plate and a chimney. Decay heat from the core debris is simulated by electrical heating of the heat shield plate. An opening is provided in the cover plate to reproduce the situation in the actual accident where the core debris would have breached a part of the core support structure. Experiments were carried out with different heat flux levels prevailing upon the heat shield plate. Temperature monitoring was done at more than 100 locations, distributed both on the solid components and in water. The temperature data was analysed to get the temperature profile at different steady state conditions. Flow visualisation was also carried out using water soluble dye to establish the direction of the convective currents. The captured images show that water flows through the slots provided in the top portion of the chimney in the upward direction as evidenced from the diffusion of dye injected inside the chimney. Both the temperature data and flow visualisation confirm mixing of water through the opening in the core support structure which indicates that natural convection is set up in that zone

Heating networks and domestic central heating systems

Energy Technology Data Exchange (ETDEWEB)

Kamler, W; Wasilewski, W

1976-08-01

This is a comprehensive survey of the 26 contributions from 8 European countries submitted to the 3rd International District Heating Conference in Warsaw held on the subject 'Heating Networks and Domestic Central Heating Systems'. The contributions are grouped according to 8 groups of subjects: (1) heat carriers and their parameters; (2) system of heating networks; (3) calculation and optimization of heating networks; (4) construction of heating networks; (5) operation control and automation; (6) operational problems; (7) corrosion problems; and (8) methods of heat accounting.

Integration of space heating and hot water supply in low temperature district heating

DEFF Research Database (Denmark)

Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

2016-01-01

District heating may supply many consumers efficiently, but the heat loss from the pipes to the ground is a challenge. The heat loss may be lowered by decreasing the network temperatures for which reason low temperature networks are proposed for future district heating. The heating demand...... of the consumers involves both domestic hot water and space heating. Space heating may be provided at low temperature in low energy buildings. Domestic hot water, however, needs sufficient temperatures to avoid growth of legionella. If the network temperature is below the demand temperature, supplementary heating...... is required by the consumer. We study conventional district heating at different temperatures and compare the energy and exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature district heating. This includes direct...

Experimental investigation of natural convection induced by internal heat generation

International Nuclear Information System (INIS)

Tasaka, Y; Kudoh, Y; Takeda, Y; Yanagisawa, T

2005-01-01

Dilatation of a convection cell with respect to its Rayleigh number, one of the problems in internally heated convection, was quantitatively investigated by analyzing temperature field in a cell. The temperature field visualized by a thermo-chromic liquid crystal (TLC) expresses the cell dilatation. A calibration system was developed to convert the visualized photographs of the temperature field to the temperature field. A calibration curve correlating color information extracted from the photograph and temperature was determined from the approximately linear temperature distribution in the horizontal fluid layer using the hue method. Photos taken at various internal Rayleigh numbers were converted to the temperature field by the obtained curve. Extracting individual cells from a temperature field achieves a quantitative expression of the cell dilatation as the variation of the wavenumber of the cell with Rayleigh number increases. The temperature profile in a cell shows that high temperature areas appear at the apexes of the cell, largely different from the profile obtained by linear theory

Integral Method for the Assessment of U-RANS Effectiveness in Non-Equilibrium Flows and Heat Transfer

Science.gov (United States)

Pond, Ian; Edabi, Alireza; Dubief, Yves; White, Christopher

2015-11-01

Reynolds Average Navier Stokes (RANS) modeling has established itself as a critical design tool in many engineering applications, thanks to its superior computational efficiency. The drawbacks of RANS models are well known, but not necessarily well understood: poor prediction of transition, non equilibrium flows, mixing and heat transfer, to name the ones relevant to our study. In the present study, we use a DNS of a reciprocating channel flow driven by an oscillating pressure gradient to test several low- and high-Reynolds RANS models. Temperature is introduced as a passive scalar to study heat transfer modeling. Low-Reynolds models manage to capture the overall physics of wall shear and heat flux well, yet with some phase discrepancies, whereas high Reynolds models fail. Under the microscope of the integral method for wall shear and wall heat flux, the qualitative agreement appears more serendipitous than driven by the ability of the models to capture the correct physics. The integral method is shown to be more insightful in the benchmarking of RANS models than the typical comparisons of statistical quantities. The authors acknowledges the support of NSF and DOE under grant NSF/DOE 1258697 (VT) and 1258702 (NH).

Influence of internal channel geometry of gas turbine blade on flow structure and heat transfer

Science.gov (United States)

Szwaba, Ryszard; Kaczynski, Piotr; Telega, Janusz; Doerffer, Piotr

2017-12-01

This paper presents the study of the influence of channel geometry on the flow structure and heat transfer, and also their correlations on all the walls of a radial cooling passage model of a gas turbine blade. The investigations focus on the heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of internal cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include a corner fillets, ribs with fillet radii and a special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which has very realistic features.

On the thermodynamics of waste heat recovery from internal combustion engine exhaust gas

Science.gov (United States)

Meisner, G. P.

2013-03-01

The ideal internal combustion (IC) engine (Otto Cycle) efficiency ηIC = 1-(1/r)(γ - 1) is only a function of engine compression ratio r =Vmax/Vmin and exhaust gas specific heat ratio γ = cP/cV. Typically r = 8, γ = 1.4, and ηIC = 56%. Unlike the Carnot Cycle where ηCarnot = 1-(TC/TH) for a heat engine operating between hot and cold heat reservoirs at TH and TC, respectively, ηIC is not a function of the exhaust gas temperature. Instead, the exhaust gas temperature depends only on the intake gas temperature (ambient), r, γ, cV, and the combustion energy. The ejected exhaust gas heat is thermally decoupled from the IC engine and conveyed via the exhaust system (manifold, pipe, muffler, etc.) to ambient, and the exhaust system is simply a heat engine that does no useful work. The maximum fraction of fuel energy that can be extracted from the exhaust gas stream as useful work is (1-ηIC) × ηCarnot = 32% for TH = 850 K (exhaust) and TC = 370 K (coolant). This waste heat can be recovered using a heat engine such as a thermoelectric generator (TEG) with ηTEG> 0 in the exhaust system. A combined IC engine and TEG system can generate net useful work from the exhaust gas waste heat with efficiency ηWH = (1-ηIC) × ηCarnot ×ηTEG , and this will increase the overall fuel efficiency of the total system. Recent improvements in TEGs yield ηTEG values approaching 15% giving a potential total waste heat conversion efficiency of ηWH = 4.6%, which translates into a fuel economy improvement approaching 5%. This work is supported by the US DOE under DE-EE0005432.

Professional Development for International Teachers: Examining TPACK and Technology Integration Decision Making

Science.gov (United States)

Dalal, Medha; Archambault, Leanna; Shelton, Catharyn

2017-01-01

This mixed-methods study explored the impacts of a semester-long technology professional development for secondary school international teachers from developing nations around the world. We used (a) a survey approach to examine international teachers' perceived technology integration abilities using the technological pedagogical content knowledge…

Integration of Space Heating and Hot Water Supply in Low Temperature District Heating

DEFF Research Database (Denmark)

Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

2014-01-01

pipes, where the water is at the highest temperature. The heat loss may be lowered by decreasing the temperatures in the network for which reason low temperature networks are proposed as a low loss solution for future district heating. However, the heating demand of the consumers involve both domestic......District heating makes it possible to provide heat for many consumers in an efficient manner. In particular, district heating based on combined heat and power production is highly efficient. One disadvantage of district heating is that there is a significant heat loss from the pipes...... to the surrounding ground. In larger networks involving both transmission and distribution systems, the heat loss is most significant from the distribution network. An estimate is that about 80-90 % of the heat loss occurs in the distribution system. In addition, the heat loss is naturally highest from the forward...

On understanding of external and internal integration in supply chains : Challenges and evaluation

OpenAIRE

HULTHÉN, HANA

2016-01-01

Benefits of implementing Supply Chain Integration (SCI) are acknowledged in existing integration literature. Integration extending beyond functional silos and firm boundaries is expected to provide value for customers in terms of higher quality, improved service level, and reduced costs. In addition, internal integration allows business functions to align around a single company goal. This type of integration promotes value creation while decreasing redundancies and costs. Yet, regardless of ...

Does Bilateral Market and Financial Integration Explains International Co-Movement Patterns1

Directory of Open Access Journals (Sweden)

Mobeen Ur Rehman

2016-05-01

Full Text Available This study aims to explore the relationship between market integration, foreign portfolio equity holding and inflation rates on international stock market linkages between Pakistan and India. To measure stock equity interlinkage, we constructed international co-movement index through rolling beta estimation. Market integration variable between these two countries is constructed using the International Capital Asset Pricing Model (ICAPM. To check the impact of market integration, foreign portfolio equity holding and inflation rate on Pakistan-Indian stock market co-movement, we applied autoregressive distributed lag (ARDL estimation. ARDL estimation is applied due to different stationarity levels of the included variables. The level of convergence speed is measured by the introduction of error correction term (ECT followed by variance decomposition analysis. Results of the study indicated presence of long term relationship among the included variables along with significance variance in bilateral co-movement due to inflation rate differential. The significance of inflation rate differences between these two countries are in accordance with portfolio balance theory stating that investors possess information about the macroeconomic variables thereby readjusting their portfolios for effective diversification.

Monte Carlo study of internal energy and specific heat of a nano-graphene bilayer in a longitudinal magnetic field

Energy Technology Data Exchange (ETDEWEB)

Luo, Xiao-hong; Wang, Wei, E-mail: ww9803@126.com; Chen, Dong-dong; Xu, Si-yuan

2016-06-15

The thermodynamic properties of a nano-graphene bilayer, consisting of the upper layer A of spin-3/2 with antiferromagnetic intralayer exchange coupling and the bottom layer B of spin-5/2 with ferromagnetic intralayer exchange coupling, have been studied by the use of Monte Carlo simulation. We find a number of characteristic phenomena. The effects of the exchange coupling, the single-ion anisotropy and the longitudinal magnetic field on the internal energy, the specific heat and the blocking temperature of the mixed-spin bilayer system have been investigated in detail. The internal energy and the specific heat profiles are clarified. In particular, we have found that the specific heat curve may show two peaks phenomenon for appropriate values of the system parameters.

Energy models. Integrated heating and cooling in different sports fields and halls; Energiamalli. Urheilupaikkojen integroitu laemmitys ja jaeaehdytys (UPILAEJAE)

Energy Technology Data Exchange (ETDEWEB)

Aittomaeki, A.; Maekinen, A.

2009-07-01

The efficient use of energy is playing an increasing role in saving natural resources and in maintaining competitiveness. The system integration plays an essential role when efficiency is maximized. Expressed in thermodynamical terms the question is about minimizing the loss of energy. When planning the integration of heating and cooling the impacts of different coupling possibilities and measurements should be compared. In this report the modeling or simulation of energy balances studies in different systems is described. In the system integration of different sports buildings the modeling parts are the following: office space with heating systems, indoor ice-skating rink, skiing tunnel, indoor swimming pool, sports-field and sport center

Integrated Thermal Protection Systems and Heat Resistant Structures

Science.gov (United States)

Pichon, Thierry; Lacoste, Marc; Glass, David E.

2006-01-01

In the early stages of NASA's Exploration Initiative, Snecma Propulsion Solide was funded under the Exploration Systems Research & Technology program to develop integrated thermal protection systems and heat resistant structures for reentry vehicles. Due to changes within NASA's Exploration Initiative, this task was cancelled early. This presentation provides an overview of the work that was accomplished prior to cancellation. The Snecma team chose an Apollo-type capsule as the reference vehicle for the work. They began with the design of a ceramic aft heatshield (CAS) utilizing C/SiC panels as the capsule heatshield, a C/SiC deployable decelerator and several ablators. They additionally developed a health monitoring system, high temperature structures testing, and the insulation characterization. Though the task was pre-maturely cancelled, a significant quantity of work was accomplished.

Comparative Evaluation of Integrated Waste Heat Utilization Systems for Coal-Fired Power Plants Based on In-Depth Boiler-Turbine Integration and Organic Rankine Cycle

Directory of Open Access Journals (Sweden)

Shengwei Huang

2018-01-01

Full Text Available To maximize the system-level heat integration, three retrofit concepts of waste heat recovery via organic Rankine cycle (ORC, in-depth boiler-turbine integration, and coupling of both are proposed, analyzed and comprehensively compared in terms of thermodynamic and economic performances. For thermodynamic analysis, exergy analysis is employed with grand composite curves illustrated to identify how the systems are fundamentally and quantitatively improved, and to highlight key processes for system improvement. For economic analysis, annual revenue and investment payback period are calculated based on the estimation of capital investment of each component to identify the economic feasibility and competitiveness of each retrofit concept proposed. The results show that the in-depth boiler-turbine integration achieves a better temperature match of heat flows involved for different fluids and multi-stage air preheating, thus a significant improvement of power output (23.99 MW, which is much larger than that of the system with only ORC (6.49 MW. This is mainly due to the limitation of the ultra-low temperature (from 135 to 75 °C heat available from the flue gas for ORC. The thermodynamic improvement is mostly contributed by the reduction of exergy destruction within the boiler subsystem, which is eventually converted to mechanical power; while the exergy destruction within the turbine system is almost not changed for the three concepts. The selection of ORC working fluids is performed to maximize the power output. Due to the low-grade heat source, the cycle with R11 offers the largest additional net power generation but is not significantly better than the other preselected working fluids. Economically, the in-depth boiler-turbine integration is the most economic completive solution with a payback period of only 0.78 year. The ORC concept is less attractive for a sole application due to a long payback time (2.26 years. However, by coupling both

Performance of heat engines with non-zero heat capacity

International Nuclear Information System (INIS)

Odes, Ron; Kribus, Abraham

2013-01-01

Highlights: ► Finite heat capacity is a second irreversibility mechanism in addition to thermal resistance. ► Heat capacity introduces thermal transients and reverse heat flow. ► Engine maximum power and efficiency are lower for finite heat capacity. ► Implementing the optimal engine cycle requires active control. - Abstract: The performance of a heat engine is analyzed subject to two types of irreversibility: a non-zero heat capacity, together with the more common finite heat transfer rate between the engine and the external heat reservoirs. The heat capacity represents an engine body that undergoes significant temperature variations during the engine cycle. An option to cut off the heat exchange between the engine and the external surrounding for part of the engine cycle is also explored. A variational approach was taken to find the engine’s internal temperature profile (which defines the internal thermodynamic cycle) that would produce maximum power. The maximum power is shown to be lower than the case of zero heat capacity, due to a loss of heat that is stored in the engine body and then lost, bypassing the thermodynamic cycle. The maximum efficiency and the efficiency at maximum power are also lower than the zero heat capacity case. Similar to the Curzon–Ahlborn analysis, power can be traded for increased efficiency, but for high heat capacity, the range of efficiency that is available for such a trade is diminished. Isolating the engine during part of the cycle reduces maximum power, but the efficiency at maximum power and the maximum efficiency are improved, due to better exploitation of heat stored in the engine body. This might be useful for real engines that are limited by the internal energy change during a single engine cycle or by the operating frequency, leading to a broader power–efficiency curve.

Integrated development planning in South Africa: lessons for international peacebuiling?

CSIR Research Space (South Africa)

Gueli, R

2007-01-01

Full Text Available to overcome Apartheid’s violent history, deserves closer scrutiny by international peacebuilding experts. This is because South Africa’s approach to development – although not perfect – is centred on integrated governance and has, to some extent, played...

Combined cycle power plant with integrated low temperature heat (LOTHECO)

International Nuclear Information System (INIS)

Kakaras, E.; Doukelis, A.; Leithner, R.; Aronis, N.

2004-01-01

The major driver to enhance the efficiency of the simple gas turbine cycle has been the increase in process conditions through advancements in materials and cooling methods. Thermodynamic cycle developments or cycle integration are among the possible ways to further enhance performance. The current paper presents the possibilities and advantages from the LOTHECO natural gas-fired combined cycle concept. In the LOTHECO cycle, low-temperature waste heat or solar heat is used for the evaporation of injected water droplets in the compressed air entering the gas turbine's combustion chamber. Following a description of this innovative cycle, its advantages are demonstrated by comparison between different gas turbine power generation systems for small and large-scale applications, including thermodynamic and economic analysis. A commercial gas turbine (ALSTOM GT10C) has been selected and computed with the heat mass balance program ENBIPRO. The results from the energy analysis are presented and the features of each concept are discussed. In addition, the exergy analysis provides information on the irreversibilities of each process and suggested improvements. Finally, the economic analysis reveals that the combined cycle plant with a heavy-duty gas turbine is the most efficient and economic way to produce electricity at base load. However, on a smaller scale, innovative designs, such as the LOTHECO concept, are required to reach the same level of performance at feasible costs

Thermodynamic modeling and evaluation of high efficiency heat pipe integrated biomass Gasifier–Solid Oxide Fuel Cells–Gas Turbine systems

International Nuclear Information System (INIS)

Santhanam, S.; Schilt, C.; Turker, B.; Woudstra, T.; Aravind, P.V.

2016-01-01

This study deals with the thermodynamic modeling of biomass Gasifier–SOFC (Solid Oxide Fuel Cell)–GT (Gas Turbine) systems on a small scale (100 kW_e). Evaluation of an existing biomass Gasifier–SOFC–GT system shows highest exergy losses in the gasifier, gas turbine and as waste heat. In order to reduce the exergy losses and increase the system's efficiency, improvements are suggested and the effects are analyzed. Changing the gasifying agent for air to anode gas gave the largest increase in the electrical efficiency. However, heat is required for an allothermal gasification to take place. A new and simple strategy for heat pipe integration is proposed, with heat pipes placed in between stacks in series, rather than the widely considered approach of integrating the heat pipes within the SOFC stacks. The developed system based on a Gasifier–SOFC–GT combination improved with heat pipes and anode gas recirculation, increases the electrical efficiency from approximately 55%–72%, mainly due to reduced exergy losses in the gasifier. Analysis of the improved system shows that operating the system at possibly higher operating pressures, yield higher efficiencies within the range of the operating pressures studied. Further the system was scaled up with an additional bottoming cycle achieved electrical efficiency of 73.61%. - Highlights: • A new and simple strategy for heat pipe integration between SOFC and Gasifier is proposed. • Anode exhaust gas is used as a gasifying agent. • The new proposed Gasifier–SOFC–GT system achieves electrical efficiency of 72%. • Addition of steam rankine bottoming cycle to proposed system increases electrical efficiency to 73.61%.

Thermo-Hydraulic Analysis of Heat Storage Filled with the Ceramic Bricks Dedicated to the Solar Air Heating System.

Science.gov (United States)

Nemś, Magdalena; Nemś, Artur; Kasperski, Jacek; Pomorski, Michał

2017-08-12

This article presents the results of a study into a packed bed filled with ceramic bricks. The designed storage installation is supposed to become part of a heating system installed in a single-family house and eventually to be integrated with a concentrated solar collector adapted to climate conditions in Poland. The system's working medium is air. The investigated temperature ranges and air volume flow rates in the ceramic bed were dictated by the planned integration with a solar air heater. Designing a packed bed of sufficient parameters first required a mathematical model to be constructed and heat exchange to be analyzed, since heat accumulation is a complex process influenced by a number of material properties. The cases discussed in the literature are based on differing assumptions and different formulas are used in calculations. This article offers a comparison of various mathematical models and of system operating parameters obtained from these models. The primary focus is on the Nusselt number. Furthermore, in the article, the thermo-hydraulic efficiency of the investigated packed bed is presented. This part is based on a relationship used in solar air collectors with internal storage.

Thermo-Hydraulic Analysis of Heat Storage Filled with the Ceramic Bricks Dedicated to the Solar Air Heating System

Science.gov (United States)

Nemś, Magdalena; Nemś, Artur; Kasperski, Jacek; Pomorski, Michał

2017-01-01

This article presents the results of a study into a packed bed filled with ceramic bricks. The designed storage installation is supposed to become part of a heating system installed in a single-family house and eventually to be integrated with a concentrated solar collector adapted to climate conditions in Poland. The system’s working medium is air. The investigated temperature ranges and air volume flow rates in the ceramic bed were dictated by the planned integration with a solar air heater. Designing a packed bed of sufficient parameters first required a mathematical model to be constructed and heat exchange to be analyzed, since heat accumulation is a complex process influenced by a number of material properties. The cases discussed in the literature are based on differing assumptions and different formulas are used in calculations. This article offers a comparison of various mathematical models and of system operating parameters obtained from these models. The primary focus is on the Nusselt number. Furthermore, in the article, the thermo-hydraulic efficiency of the investigated packed bed is presented. This part is based on a relationship used in solar air collectors with internal storage. PMID:28805703

Numerical investigation of premixed combustion in a porous burner with integrated heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Farzaneh, Meisam; Shafiey, Mohammad; Shams, Mehrzad [K.N. Toosi University of Technology, Department of Mechanical Engineering, Tehran (Iran, Islamic Republic of); Ebrahimi, Reza [K.N. Toosi University of Technology, Department of Aerospace Engineering, Tehran (Iran, Islamic Republic of)

2012-07-15

In this paper, we perform a numerical analysis of a two-dimensional axisymmetric problem arising in premixed combustion in a porous burner with integrated heat exchanger. The physical domain consists of two zones, porous and heat exchanger zones. Two dimensional Navier-Stokes equations, gas and solid energy equations, and chemical species transport equations are solved and heat release is described by a multistep kinetics mechanism. The solid matrix is modeled as a gray medium, and the finite volume method is used to solve the radiative transfer equation to calculate the local radiation source/sink in the solid phase energy equation. Special attention is given to model heat transfer between the hot gas and the heat exchanger tube. Thus, the corresponding terms are added to the energy equations of the flow and the solid matrix. Gas and solid temperature profiles and species mole fractions on the burner centerline, predicted 2D temperature fields, species concentrations and streamlines are presented. Calculated results for temperature profiles are compared to experimental data. It is shown that there is good agreement between the numerical solutions and the experimental data and it is concluded that the developed numerical program is an excellent tool to investigate combustion in porous burner. (orig.)

FY 17 Q1 Commercial integrated heat pump with thermal storage milestone report

Energy Technology Data Exchange (ETDEWEB)

Abu-Heiba, Ahmad [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-01-01

The commercial integrated heat pump with thermal storage (AS-IHP) offers significant energy saving over a baseline heat pump with electric water heater. The saving potential is maximized when the AS-IHP serves coincident high water heating and high space cooling demands. A previous energy performance analysis showed that the AS-IHP provides the highest benefit in the hot-humid and hot-dry/mixed dry climate regions. Analysis of technical potential energy savings for these climate zones based on the BTO Market calculator indicated that the following commercial building market segments had the highest water heating loads relative to space cooling and heating loads education, food service, health care, lodging, and mercantile/service. In this study, we focused on these building types to conservatively estimate the market potential of the AS-IHP. Our analysis estimates maximum annual shipments of ~522,000 units assuming 100% of the total market is captured. An early replacement market based on replacement of systems in target buildings between 15 and 35 years old was estimated at ~136,000 units. Technical potential energy savings are estimated at ~0.27 quad based on the maximum market estimate, equivalent to ~13.9 MM Ton CO2 emissions reduction.

Dynamic simulation of periodic adsorption heat pumps. Dynamische Simulation periodischer Adsorptionswaermepumpen

Energy Technology Data Exchange (ETDEWEB)

Foellinger, T.

1989-01-01

Periodic asorption heat pumps with water as working fluid and two types of zeolites as adsorption agents were studied theoretically by a dynamic simulation analysis in order to find out whether they are suited as high-temperature heat pumps for heat recovery. Variants with one and two pairs of containers were investigated. Internal heat transfer is possible between the containers of each pair, and shifting temperature and load profiles (zoned sorption) are generated inside the containers in order to raise the heat ratio (efficience). The heat ratios are clearly higher than in ammonia/water heat pumps of the same size. The external heat transfer is kept constant by means of control elements and buffer systems, so that the periodic heat pump can be integrated in a continuous process. A pilot plant was developed on the basis of the results, with particular interest taken in the design of the liquid/solid heat transfer media. (orig.) With 47 figs., 3 tabs.

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

Applying an international CAPM to herding behaviour model for integrated stock markets

Directory of Open Access Journals (Sweden)

Najmudin Najmudin

2017-12-01

Full Text Available Development of financial globalization in the form of stock market integration experiences a trend which is getting stronger. The analysis models in the field of finance and investments should be able to adjust to these developments. This adjustment includes the models used to detect the existence of herding behavior. All this time, the herding behavior model of individual stocks towards market consensus has been referring to CAPM theory. The basic assumption of CAPM is that financial assets at a domestic stock market are segmented from the financial assets’ movement at the global market. Therefore, this paper aims to provide an alternative view in the form of an international herding model that should be applied in the context of an integrated stock market. The model was created with reference to the international CAPM. This paper combined ICAPM method and international CSAD model to identify herding for eight stock markets, the sample period being from January 2003 to December 2016. The result found that for segmented stock markets, represented by China and the Philippines, herding happened for both overall the sample period and the market crisis period. In addition, for the integrated stock markets, represented by Indonesia, Japan, Malaysia, Singapore, Thailand, and the UK, herding behavior was only found during the market crisis period. Therefore, classification of market integrations should be considered in assessing the herding behaviour at stock markets.

Unprecedented Integral-Free Debye Temperature Formulas: Sample Applications to Heat Capacities of ZnSe and ZnTe

Directory of Open Access Journals (Sweden)

R. Pässler

2017-01-01

Full Text Available Detailed analytical and numerical analyses are performed for combinations of several complementary sets of measured heat capacities, for ZnSe and ZnTe, from the liquid-helium region up to 600 K. The isochoric (harmonic parts of heat capacities, CVh(T, are described within the frame of a properly devised four-oscillator hybrid model. Additional anharmonicity-related terms are included for comprehensive numerical fittings of the isobaric heat capacities, Cp(T. The contributions of Debye and non-Debye type due to the low-energy acoustical phonon sections are represented here for the first time by unprecedented, integral-free formulas. Indications for weak electronic contributions to the cryogenic heat capacities are found for both materials. A novel analytical framework has been constructed for high-accuracy evaluations of Debye function integrals via a couple of integral-free formulas, consisting of Debye’s conventional low-temperature series expansion in combination with an unprecedented high-temperature series representation for reciprocal values of the Debye function. The zero-temperature limits of Debye temperatures have been detected from published low-temperature Cp(T data sets to be significantly lower than previously estimated, namely, 270 (±3 K for ZnSe and 220 (±2 K for ZnTe. The high-temperature limits of the “true” (harmonic lattice Debye temperatures are found to be 317 K for ZnSe and 262 K for ZnTe.

Dependence of core heating properties on heating pulse duration and intensity

Science.gov (United States)

Johzaki, Tomoyuki; Nagatomo, Hideo; Sunahara, Atsushi; Cai, Hongbo; Sakagami, Hitoshi; Mima, Kunioki

2009-11-01

In the cone-guiding fast ignition, an imploded core is heated by the energy transport of fast electrons generated by the ultra-intense short-pulse laser at the cone inner surface. The fast core heating (˜800eV) has been demonstrated at integrated experiments with GEKKO-XII+ PW laser systems. As the next step, experiments using more powerful heating laser, FIREX, have been started at ILE, Osaka university. In FIREX-I (phase-I of FIREX), our goal is the demonstration of efficient core heating (Ti ˜ 5keV) using a newly developed 10kJ LFEX laser. In the first integrated experiments, the LFEX laser is operated with low energy mode (˜0.5kJ/4ps) to validate the previous GEKKO+PW experiments. Between the two experiments, though the laser energy is similar (˜0.5kJ), the duration is different; ˜0.5ps in the PW laser and ˜ 4ps in the LFEX laser. In this paper, we evaluate the dependence of core heating properties on the heating pulse duration on the basis of integrated simulations with FI^3 (Fast Ignition Integrated Interconnecting) code system.

Modeling of Combined Heat and Power Plant Based on a Multi-Stage Gasifier and Internal Combustion Engines of Various Power Outputs

Science.gov (United States)

Khudyakova, G. I.; Kozlov, A. N.; Svishchev, D. A.

2017-11-01

The paper is concerned with an integrated system of internal combustion engine and mini combined heat and power plant (ICE-CHP). The system is based on multi-stage wood biomass gasification. The use of producer gas in the system affects negatively the internal combustion engine performance and, therefore, reduces the efficiency of the ICE-CHP plant. A mathematical model of an internal combustion engine running on low-calorie producer gas was developed using an overview of Russian and foreign manufacturers of reciprocating units, that was made in the research. A thermal calculation was done for four-stroke gas engines of different rated power outputs (30, 100 and 250 kW), running on producer gas (CO2 - 10.2, CO - 45.8, N2 - 38.8%). Thermal calculation demonstrates that the engine exhaust gas temperature reaches 500 - 600°C at the rated power level and with the lower engine power, the temperature gets higher. For example, for an internal combustion engine power of 1000 kW the temperature of exhaust gases equals 400°C. A comparison of the efficiency of engine operation on natural gas and producer gas shows that with the use of producer gas the power output declines from 300 to 250 kWe. The reduction in the effective efficiency in this case makes up 2%. The measures are proposed to upgrade the internal combustion engine to enable it to run on low-calorie producer gas.

Integration of Heat Transfer, Stress, and Particle Trajectory Simulation. Final report

International Nuclear Information System (INIS)

Bui, Thuc; Read, Michael; Ives, Lawrence

2012-01-01

Calabazas Creek Research, Inc. developed and currently markets Beam Optics Analyzer (BOA) in the United States and abroad. BOA is a 3D, charged particle optics code that solves the electric and magnetic fields with and without the presence of particles. It includes automatic and adaptive meshing to resolve spatial scales ranging from a few millimeters to meters. It is fully integrated with CAD packages, such as SolidWorks, allowing seamless geometry updates. The code includes iterative procedures for optimization, including a fully functional, graphical user interface. Recently, time dependent, particle in cell capability was added, pushing particles synchronically under quasistatic electromagnetic fields to obtain particle bunching under RF conditions. A heat transfer solver was added during this Phase I program. Completed tasks include: (1) Added a 3D finite element heat transfer solver with adaptivity; (2) Determined the accuracy of the linear heat transfer field solver to provide the basis for development of higher order solvers in Phase II; (3) Provided more accurate and smoother power density fields; and (4) Defined the geometry using the same CAD model, while maintaining different meshes, and interfacing the power density field between the particle simulator and heat transfer solvers. These objectives were achieved using modern programming techniques and algorithms. All programming was in C++ and parallelization in OpenMP, utilizing state-of-the-art multi-core technology. Both x86 and x64 versions are supported. The GUI design and implementation used Microsoft Foundation Class.

Heat transfer and thermodynamic performance of convective–radiative cooling double layer walls with temperature-dependent thermal conductivity and internal heat generation

International Nuclear Information System (INIS)

Torabi, Mohsen; Zhang, Kaili

2015-01-01

Highlights: • First and second laws of thermodynamics have been investigated in a composite wall. • Convective–radiative heat transfer is assumed on both surfaces. • Optimum interface location is calculated to minimize the total entropy generation rate. • Thermal conductivities ratio has great effects on the temperature and entropy generation. - Abstract: Composite geometries have numerous applications in industry and scientific researches. This work investigates the temperature distribution, and local and total entropy generation rates within two-layer composite walls using conjugate convection and radiation boundary conditions. Thermal conductivities of the materials of walls are assumed temperature-dependent. Temperature-dependent internal heat generations are also incorporated into the modeling. The differential transformation method (DTM) is used as an analytical technique to tackle the highly nonlinear system of ordinary differential equations. Thereafter, the local and total entropy generation rates are calculated using the DTM formulated temperature distribution. An exact analytical solution, for the temperature-independent model without radiation effect, is also derived. The correctness and accuracy of the DTM solution are checked against the exact solution. After verification, effects of thermophysical parameters such as location of the interface, convection–conduction parameters, radiation–conduction parameters, and internal heat generations, on the temperature distribution, and both local and total entropy generation rates are examined. To deliver the minimum total entropy generation rate, optimum values for some parameters are also found. Since composite walls are widely used in many fields, the abovementioned investigation is a beneficial tool for many engineering industries and scientific fields to minimize the entropy generation, which is the exergy destruction, of the system

Development of a new distillation unit combined with compressed heat pump (heat integrated distillation column (HIDiC)) (eco-energy city project)

Energy Technology Data Exchange (ETDEWEB)

Nakanishi, Toshinari; Aso, Kazumasa [Kimura Chemical Plants Co., Ltd., Amagasaki City, Hyogo (Japan); Takamatsu, Takeichiro [Research Inst. of Industrial Technology, Suita-City, Osaka (Japan); Nakaiwa, Masaru [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan); Noda, Hideo; Kuratani, Nobuyuki [Kansai Chemical Engineearing Co., Ltd., Amagasaki-city, Hyogo (Japan); Yoshida, Kazufumi [Maruzen Petrochemical Co., Ltd., 25-10, Tokyo (Japan)

1999-07-01

To reduce the irreversible loss the Heat Integrated Distillation Column (HIDiC) is proposed by application of heat-pump technology. (Distillation column, which is an energy consuming separation unit, has been widely used in oil refinery and the other chemical-related plants. The reason why it is a major energy consumer is that a large amount of irreversible loss occurs in heat transfer within the process.) In this paper, current results on the study of HIDiC in both simulations and experiments are shown. HIDiC must be operated at a higher pressure in the rectifying section so as to make its temperature higher than that of the stripping section which stands parallel with the rectifying section. That makes heat transfer from the rectifying section to the stripping section. Because of vaporization in the stripping section and condensation in the rectifying section, the energy for the reboiler can be saved. The degree of energy saving can be expected to be much more than 30%, although the exact value depends on the characteristics of mixture to be separated. (The degree of energy saving is higher than the above, if the exhaust vapor from the HIDiC is used to heat the feed or the other processes.) To save energy by the HIDiC, high separation performances and heat transfer capabilities are required. It has been found out that the HIDiC, whose shape is like vertical shell and tube heat exchanger was enough to be practical use of the HIDiC from the static design principle points of view. (orig.)

Geothermal heat-pump systems of heat supply

International Nuclear Information System (INIS)

Vasil'ev, G.P.

2004-01-01

The data on the multilayer operation of the objects, located in the climatic conditions of the central area of Russia and equipped with the geothermal heat-pumping systems of the heat supply are presented. The results of the analytical studies on evaluating the geothermal heat-pumping systems of the heat supply integration efficiency into the structure of the energy supply system, prevailing in the country, are presented [ru

Solidarity and its limits for economic integration in the EU’s internal market

DEFF Research Database (Denmark)

Butler, Graham

2018-01-01

Solidarity is applicable to multiple strands of Union law, including in the fostering of an internal market. Whereas the internal market has always held constitutional status, the objects that underlie it came about much later. The question of how solidarity, as a principle, value, and concept...... of the internal market, but also for the purposes of economic integration. The article demonstrates that solidarity in law can be a reason or justification for measures to promote the treaty-based aim of the internal market. Yet simultaneously, it finds that solidarity is not an all-encompassing principle, value......, or concept in absolute terms, and has limits for utilisation in the spirit of European integration. Conclusively, by demonstrating the limits of solidarity as a ‘legal’ principle, value, or concept, the article asks whether it is time to reassess the role that solidarity should play in Union law...

Dual reciprocity boundary element analysis for the laminar forced heat convection problem in concentric annulus

International Nuclear Information System (INIS)

Choi, Chang Yong

1999-01-01

This paper presents a study of the Dual Reciprocity Boundary Element Method (DRBEM) for the laminar heat convection problem in a concentric annulus with constant heat flux boundary condition. DRBEM is one of the most successful technique used to transform the domain integrals arising from the nonhomogeneous term of the poisson equation into equivalent boundary only integrals. This recently developed and highly efficient numerical method is tested for the solution accuracy of the fluid flow and heat transfer study in a concentric annulus. Since their exact solutions are available, DRBEM solutions are verified with different number of boundary element discretization and internal points. The results obtained in this study are discussed with the relative error percentage of velocity and temperature solutions, and potential applicability of the method for the more complicated heat convection problems with arbitrary duct geometries

Stability Analysis and Internal Heating Effect on Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium Under Gravity Modulation

Science.gov (United States)

Bhadauria, B. S.; Singh, M. K.; Singh, A.; Singh, B. K.; Kiran, P.

2016-12-01

In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.

A study of the internal humidification of an integrated PEMFC stack

Energy Technology Data Exchange (ETDEWEB)

Choi, K H; Lee, T H [Yonsei Univ., Seoul (Korea, Republic of). Dept. of Chemical Engineering; Park, D J; Rho, Y W; Kho, Y T [KOGAS R and D Center, Kyunggi (Korea, Republic of)

1998-07-15

An integrated proton exchange membrane fuel-cell (PFMFC) system has been developed with an internal humidifier within the stack. Research is concentrated on selecting a membrane with low cost and good water permeability because, to date, high-cost membranes (e.g., as Nafion) have been used. The gas and water permeability of several membranes were measured. A low-cost ultra filtration (UF) membrane shows better characteristics for the internal humidifier and cell performance than the others. Also, saturated water vapour permeating through the UF membrane can be supplied at the stack from the internal humidifier. The internal humidifier using UF membrane is thought to be a satisfactory humidifier for a PEMPC. (orig.)