Meeting residential space heating demand with wind-generated electricity

International Nuclear Information System (INIS)

Hughes, Larry

2010-01-01

Worldwide, many electricity suppliers are faced with the challenge of trying to integrate intermittent renewables, notably wind, into their energy mix to meet the needs of those services that require a continuous supply of electricity. Solutions to intermittency include the use of rapid-response backup generation and chemical or mechanical storage of electricity. Meanwhile, in many jurisdictions with lengthy heating seasons, finding secure and preferably environmentally benign supplies of energy for space heating is also becoming a significant challenge because of volatile energy markets. Most, if not all, electricity suppliers treat these twin challenges as separate issues: supply (integrating intermittent renewables) and demand (electric space heating). However, if space heating demand can be met from an intermittent supply of electricity, then both of these issues can be addressed simultaneously. One such approach is to use off-the-shelf electric thermal storage systems. This paper examines the potential of this approach by applying the output from a 5.15 MW wind farm to the residential heating demands of detached households in the Canadian province of Prince Edward Island. The paper shows that for the heating season considered, up to 500 households could have over 95 percent of their space heating demand met from the wind farm in question. The benefits as well as the limitations of the approach are discussed in detail. (author)

Theoretical energy and exergy analyses of solar assisted heat pump space heating system

Directory of Open Access Journals (Sweden)

Atmaca Ibrahim

2014-01-01

Full Text Available Due to use of alternative energy sources and energy efficient operation, heat pumps come into prominence in recent years. Especially in solar-assisted heat pumps, sizing the required system is difficult and arduous task in order to provide optimum working conditions. Therefore, in this study solar assisted indirect expanded heat pump space heating system is simulated and the results of the simulation are compared with available experimental data in the literature in order to present reliability of the model. Solar radiation values in the selected region are estimated with the simulation. The case study is applied and simulation results are given for Antalya, Turkey. Collector type and storage tank capacity effects on the consumed power of the compressor, COP of the heat pump and the overall system are estimated with the simulation, depending on the radiation data, collector surface area and the heating capacity of the space. Exergy analysis is also performed with the simulation and irreversibility, improvement potentials and exergy efficiencies of the heat pump and system components are estimated.

Green hypocrisy? Environmental attitudes and residential space heating expenditure

OpenAIRE

Traynor, Laura; Lange, Ian A.; Moro, Mirko

2012-01-01

In the UK, the largest proportion of household energy use is for space heating. Popular media make claims of a green hypocrisy: groups which have the strongest attitude towards the environment have the highest emissions. This study examines whether environmental attitudes and behaviours are associated with space heating energy use using data from the British Household Panel Survey. Results find that environmentally friendly attitudes generally do not lead to lower heating expenditures though ...

Hybrid Heat Pipes for Lunar and Martian Surface and High Heat Flux Space Applications

Science.gov (United States)

Ababneh, Mohammed T.; Tarau, Calin; Anderson, William G.; Farmer, Jeffery T.; Alvarez-Hernandez, Angel R.

2016-01-01

Novel hybrid wick heat pipes are developed to operate against gravity on planetary surfaces, operate in space carrying power over long distances and act as thermosyphons on the planetary surface for Lunar and Martian landers and rovers. These hybrid heat pipes will be capable of operating at the higher heat flux requirements expected in NASA's future spacecraft and on the next generation of polar rovers and equatorial landers. In addition, the sintered evaporator wicks mitigate the start-up problems in vertical gravity aided heat pipes because of large number of nucleation sites in wicks which will allow easy boiling initiation. ACT, NASA Marshall Space Flight Center, and NASA Johnson Space Center, are working together on the Advanced Passive Thermal experiment (APTx) to test and validate the operation of a hybrid wick VCHP with warm reservoir and HiK"TM" plates in microgravity environment on the ISS.

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

Science.gov (United States)

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

2017-11-01

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

Green hypocrisy? Environmental attitudes and residential space heating expenditure

Energy Technology Data Exchange (ETDEWEB)

Traynor, Laura; Lange, Ian; Moro, Mirko [Stirling Univ. (United Kingdom). Division of Economics

2012-06-15

In the UK, the largest proportion of household energy use is for space heating. Popular media make claims of a green hypocrisy: groups which have the strongest attitude towards the environment have the highest emissions. This study examines whether environmental attitudes and behaviours are associated with space heating energy use using data from the British Household Panel Survey. Results find that environmentally friendly attitudes generally do not lead to lower heating expenditures though environmentally friendly behaviours are associated with lower heating expenditure. Also, the effect of these attitudes and behaviours do not change as income increase.

Validated TRNSYS Model for Solar Assisted Space Heating System

International Nuclear Information System (INIS)

Abdalla, Nedal

2014-01-01

The present study involves a validated TRNSYS model for solar assisted space heating system as applied to a residential building in Jordan using new detailed radiation models of the TRNSYS 17.1 and geometric building model Trnsys3d for the Google SketchUp 3D drawing program. The annual heating load for a building (Solar House) which is located at the Royal ScientiFIc Society (RS5) in Jordan is estimated under climatological conditions of Amman. The aim of this Paper is to compare measured thermal performance of the Solar House with that modeled using TRNSYS. The results showed that the annual measured space heating load for the building was 6,188 kWh while the heati.ng load for the modeled building was 6,391 kWh. Moreover, the measured solar fraction for the solar system was 50% while the modeled solar fraction was 55%. A comparison of modeled and measured data resulted in percentage mean absolute errors for solar energy for space heating, auxiliary heating and solar fraction of 13%, 7% and 10%, respectively. The validated model will be useful for long-term performance simulation under different weather and operating conditions.(author)

Climate Adaptivity and Field Test of the Space Heating Used Air-Source Transcritical CO2 Heat Pump

Science.gov (United States)

Song, Yulong; Ye, Zuliang; Cao, Feng

2017-08-01

In this study, an innovation of air-sourced transcritical CO2 heat pump which was employed in the space heating application was presented and discussed in order to solve the problem that the heating performances of the transcritical CO2 heat pump water heater deteriorated sharply with the augment in water feed temperature. An R134a cycle was adopted as a subcooling device in the proposed system. The prototype of the presented system was installed and supplied hot water for three places in northern China in winter. The field test results showed that the acceptable return water temperature can be increased up to 55°C, while the supply water temperature was raised rapidly by the presented prototype to up to 70°C directly, which was obviously appropriate to the various conditions of heating radiator in space heating application. Additionally, though the heating capacity and power dissipation decreased with the decline in ambient temperature or the augment in water temperature, the presented heat pump system performed efficiently whatever the climate and water feed temperature were. The real time COP of the presented system was generally more than 1.8 in the whole heating season, while the seasonal performance coefficient (SPC) was also appreciable, which signified that the economic efficiency of the presented system was more excellent than other space heating approaches such as fuel, gas, coal or electric boiler. As a result, the novel system will be a promising project to solve the energy issues in future space heating application.

The emissions from a space-heating biomass stove

International Nuclear Information System (INIS)

Koyuncu, T.; Pinar, Y.

2007-01-01

In this paper, the flue gas emissions of carbon monoxide (CO), nitrogen oxides (NO X ), sulphur dioxide (SO 2 ) and soot from an improved space-heating biomass stove and thermal efficiency of the stove have been investigated. Various biomass fuels such as firewood, wood shavings, hazelnut shell, walnut shell, peanut shell, seed shell of apricot (sweet and hot seed type), kernel removed corncob, wheat stalk litter (for cattle and sheep pen), cornhusk and maize stalk litter (for cattle pen) and charcoal were burned in the same space-heating biomass stove. Flue gas emissions were recorded during the combustion period at intervals of 5min. It was seen from the results that the flue gas emissions have different values depending on the characteristics of biomass fuels. Charcoal is the most appropriate biomass fuel for use in the space-heating biomass stoves because its combustion emits less smoke and the thermal efficiency of the stove is approximately 46%. (author)

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Solar system for domestic hot water and space heating

Energy Technology Data Exchange (ETDEWEB)

Weiss, W. [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

1997-12-31

The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

Solar system for domestic hot water and space heating

Energy Technology Data Exchange (ETDEWEB)

Weiss, W [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

1998-12-31

The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

Heat pump system with selective space cooling

Science.gov (United States)

Pendergrass, J.C.

1997-05-13

A reversible heat pump provides multiple heating and cooling modes and includes a compressor, an evaporator and heat exchanger all interconnected and charged with refrigerant fluid. The heat exchanger includes tanks connected in series to the water supply and a condenser feed line with heat transfer sections connected in counterflow relationship. The heat pump has an accumulator and suction line for the refrigerant fluid upstream of the compressor. Sub-cool transfer tubes associated with the accumulator/suction line reclaim a portion of the heat from the heat exchanger. A reversing valve switches between heating/cooling modes. A first bypass is operative to direct the refrigerant fluid around the sub-cool transfer tubes in the space cooling only mode and during which an expansion valve is utilized upstream of the evaporator/indoor coil. A second bypass is provided around the expansion valve. A programmable microprocessor activates the first bypass in the cooling only mode and deactivates the second bypass, and vice-versa in the multiple heating modes for said heat exchanger. In the heating modes, the evaporator may include an auxiliary outdoor coil for direct supplemental heat dissipation into ambient air. In the multiple heating modes, the condensed refrigerant fluid is regulated by a flow control valve. 4 figs.

Measure Guideline. Combination Forced-Air Space and Tankless Domestic Hot Water Heating Systems

Energy Technology Data Exchange (ETDEWEB)

Rudd, Armin [Building Science Corporation Industry Team (BSC), Somerville, MA (United States)

2012-08-01

This document describes design and application guidance for combination space and tankless domestic hot water heating systems (combination systems) used in residential buildings, based on field evaluation, testing, and industry meetings conducted by Building Science Corporation. As residential building enclosure improvements continue to drive heating loads down, using the same water heating equipment for both space heating and domestic water heating becomes attractive from an initial cost and space-saving perspective. This topic is applicable to single- and multi-family residential buildings, both new and retrofitted.

Economic feasibility of solar water and space heating.

Science.gov (United States)

Bezdek, R H; Hirshberg, A S; Babcock, W H

1979-03-23

The economic feasibility in 1977 and 1978 of solar water and combined water and space heating is analyzed for single-family detached residences and multi-family apartment buildings in four representative U.S. cities: Boston, Massachusetts; Washington, D.C.; Grand Junction, Colorado; and Los Angeles, California. Three economic decision criteria are utilized: payback period, years to recovery of down payment, and years to net positive cash flow. The cost competitiveness of the solar systems compared to heating systems based on electricity, fuel oil, and natural gas is then discussed for each city, and the impact of the federal tax credit for solar energy systems is assessed. It is found that even without federal incentives some solar water and space heating systems are competitive. Enactment of the solar tax credit, however, greatly enhances their competitiveness. The implications of these findings for government tax and energy pricing policies are discussed.

Space Launch System Base Heating Test: Experimental Operations & Results

Science.gov (United States)

Dufrene, Aaron; Mehta, Manish; MacLean, Matthew; Seaford, Mark; Holden, Michael

2016-01-01

NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Test methodology and conditions are presented, and base heating results from 76 runs are reported in non-dimensional form. Regions of high heating are identified and comparisons of various configuration and conditions are highlighted. Base pressure and radiometer results are also reported.

Capillary-Driven Heat Transfer Experiment: Keeping It Cool in Space

Science.gov (United States)

Lekan, Jack F.; Allen, Jeffrey S.

1998-01-01

Capillary-pumped loops (CPL's) are devices that are used to transport heat from one location to another--specifically to transfer heat away from something. In low-gravity applications, such as satellites (and possibly the International Space Station), CPL's are used to transfer heat from electrical devices to space radiators. This is accomplished by evaporating one liquid surface on the hot side of the CPL and condensing the vapor produced onto another liquid surface on the cold side. Capillary action, the phenomenon that causes paper towels to absorb spilled liquids, is used to "pump" the liquid back to the evaporating liquid surface (hot side) to complete the "loop." CPL's require no power to operate and can transfer heat over distances as large as 30 ft or more. Their reliance upon evaporation and condensation to transfer heat makes them much more economical in terms of weight than conventional heat transfer systems. Unfortunately, they have proven to be unreliable in space operations, and the explanation for this unreliability has been elusive. The Capillary-Driven Heat Transfer (CHT) experiment is investigating the fundamental fluid physics phenomena thought to be responsible for the failure of CPL's in low-gravity operations. If the failure mechanism can be identified, then appropriate design modifications can be developed to make capillary phase-change heat-transport devices a more viable option in space applications. CHT was conducted onboard the Space Shuttle Columbia during the first Microgravity Science Laboratory (MSL-1) mission, STS-94, which flew from July 1 to 17, 1997. The CHT glovebox investigation, which was conceived by Dr. Kevin Hallinan and Jeffrey Allen of the University of Dayton, focused on studying the dynamics associated with the heating and cooling at the evaporating meniscus within a capillary phase-change device in a low-gravity environment. The CHT experimental hardware was designed by a small team of engineers from Aerospace Design

Micro tube heat exchangers for Space, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Mezzo fabricates micro tube heat exchangers for a variety of applications, including aerospace, automotive racing, Department of Defense ground vehicles, economizers...

Heat-pipe development for the SPAR space-power system

International Nuclear Information System (INIS)

Ranken, W.A.

1981-01-01

The SPAR space power system design is based on a high temperature fast spectrum nuclear reactor that furnishes heat to a thermoelectric conversion system to generate an electrical power output of 100 kW/sub (e)/. An important feature of this design is the use of alkali metal heat pipes to provide redundant, reliable, and low-loss heat transfer at high temperature. Three sets of heat pipes are used in the system. These include sodium/molybdenum heat pipes to transfer heat from the reactor core to the conversion system, potassium/niobium heat pipes to couple the conversion system to the radiator in a redundant manner, and potassium/titanium heat pipes to distribute rejected heat throughout the radiator surface. The designs of these units are discussed and fabrication methods and testing results are described. 12 figures

Evaluation of Advanced Models for PAFS Condensation Heat Transfer in SPACE Code

Energy Technology Data Exchange (ETDEWEB)

Bae, Byoung-Uhn; Kim, Seok; Park, Yu-Sun; Kang, Kyung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ahn, Tae-Hwan; Yun, Byong-Jo [Pusan National University, Busan (Korea, Republic of)

2015-10-15

The PAFS (Passive Auxiliary Feedwater System) is operated by the natural circulation to remove the core decay heat through the PCHX (Passive Condensation Heat Exchanger) which is composed of the nearly horizontal tubes. For validation of the cooling and operational performance of the PAFS, PASCAL (PAFS Condensing Heat Removal Assessment Loop) facility was constructed and the condensation heat transfer and natural convection phenomena in the PAFS was experimentally investigated at KAERI (Korea Atomic Energy Research Institute). From the PASCAL experimental result, it was found that conventional system analysis code underestimated the condensation heat transfer. In this study, advanced condensation heat transfer models which can treat the heat transfer mechanisms with the different flow regimes in the nearly horizontal heat exchanger tube were analyzed. The models were implemented in a thermal hydraulic safety analysis code, SPACE (Safety and Performance Analysis Code for Nuclear Power Plant), and it was evaluated with the PASCAL experimental data. With an aim of enhancing the prediction capability for the condensation phenomenon inside the PCHX tube of the PAFS, advanced models for the condensation heat transfer were implemented into the wall condensation model of the SPACE code, so that the PASCAL experimental result was utilized to validate the condensation models. Calculation results showed that the improved model for the condensation heat transfer coefficient enhanced the prediction capability of the SPACE code. This result confirms that the mechanistic modeling for the film condensation in the steam phase and the convection in the condensate liquid contributed to enhance the prediction capability of the wall condensation model of the SPACE code and reduce conservatism in prediction of condensation heat transfer.

Investigation of a low flow solar heating system for space heating and domestic hot water supply for Aidt Miljø A/S

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1997-01-01

A low flow solar heating system for space heating and domestic hot water supply from Aidt Miljø A/Swas tested in a laboratory test facility.......A low flow solar heating system for space heating and domestic hot water supply from Aidt Miljø A/Swas tested in a laboratory test facility....

Investigation of a solar heating system for space heating and domestic hot water supply for Sol&Træ A.m.b.a

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1999-01-01

A solar heating system for space heating and domestic hot water supply from "Sol&Træ A.m.b.a." was tested in a laboratory test facility.......A solar heating system for space heating and domestic hot water supply from "Sol&Træ A.m.b.a." was tested in a laboratory test facility....

Titanium Loop Heat Pipes for Space Nuclear Radiators, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will develop titanium Loop Heat Pipes (LHPs) that can be used in low-mass space nuclear radiators, such as...

Accident analysis of heat pipe cooled and AMTEC conversion space reactor system

International Nuclear Information System (INIS)

Yuan, Yuan; Shan, Jianqiang; Zhang, Bin; Gou, Junli; Bo, Zhang; Lu, Tianyu; Ge, Li; Yang, Zijiang

2016-01-01

Highlights: • A transient analysis code TAPIRS for HPS has been developed. • Three typical accidents are analyzed using TAPIRS. • The reactor system has the self-stabilization ability under accident conditions. - Abstract: A space power with high power density, light weight, low cost and high reliability is of crucial importance to future exploration of deep space. Space reactor is an excellent candidate because of its unique characteristics of high specific power, low cost, strong environment adaptability and so on. Among all types of space reactors, heat pipe cooled space reactor, which adopts the passive heat pipe (HP) as core cooling component, is considered as one of the most promising choices and is widely studied all over the world. This paper develops a transient analysis code (TAPIRS) for heat pipe cooled space reactor power system (HPS) based on point reactor kinetics model, lumped parameter core heat transfer model, combined HP model (self-diffusion model, flat-front startup model and network model), energy conversion model of Alkali Metal Thermal-to-Electric Conversion units (AMTEC), and HP radiator model. Three typical accidents, i.e., control drum failure, AMTEC failure and partial loss of the heat transfer area of radiator are then analyzed using TAPIRS. By comparing the simulation results of the models and steady state with those in the references, the rationality of the models and the solution method is validated. The results show the following. (1) After the failure of one set of control drums, the reactor power finally reaches a stable value after two local peaks under the temperature feedback. The fuel temperature rises rapidly, however it is still under safe limit. (2) The fuel temperature is below a safe limit under the AMTEC failure and partial loss of the heat transfer area of radiator. This demonstrates the rationality of the system design and the potential applicability of the TAPIRS code for the future engineering application of

Experimental results of a 3 k Wh thermochemical heat storage module for space heating application

NARCIS (Netherlands)

Finck, C.J.; Henquet, E.M.R.; Soest, C.F.L. van; Oversloot, H.P.; Jong, A.J. de; Cuypers, R.; Spijker, J.C. van 't

2014-01-01

A 3 kWh thermochemical heat storage (TCS) module was built as part of an all-in house system implementation focusing on space heating application at a temperature level of 40 ºC and a temperature lift of 20 K. It has been tested and measurements showed a maximum water circuit temperature span

Investigation af a solar heating system for space heating and domestic hot water supply with a high degree of coverage

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1999-01-01

A solar storage tank for space heating and domestic hot water supply was designed and testet in af laboratory test facility.......A solar storage tank for space heating and domestic hot water supply was designed and testet in af laboratory test facility....

Investigation of a heat storage for a solar heating system for combined space heating and domestic hot water supply for homeowner´s association "Bakken"

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1998-01-01

A heat storage for a solar heating system for combined space heating and domestic hot water supply was tested in a laboratory test facility.The heat storage consist of a mantle tank with water for the heating system and of a hot water tank, which by means of thermosyphoning is heated by the water...

Transient heat pipe investigations for space power systems

International Nuclear Information System (INIS)

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

1985-01-01

A 4-meter long, high temperature, high power, molybdenum-lithium heat pipe has been fabricated and tested in transient and steady state operation at temperatures to 1500 K. Maximum power throughput during the tests was approximately 37 kW/cm 2 for the 1.4 cm diameter vapor space of the annular wick heat pipe. The evaporator flux density for the tests was 150.0 W/cm 2 over a length of 40 cm. Condenser length was approximately 3.0 m with radiant heat rejection from the condenser to a coaxial, water cooled radiation calorimeter. A variable radiation shield, controllable from the outside of the vacuum enclosure, was used to vary the load on the heat pipe during the tests. 1 ref., 9 figs

Exergy performance of different space heating systems: A theoretical study

DEFF Research Database (Denmark)

Kazanci, Ongun Berk; Shukuya, Masanori; Olesen, Bjarne W.

2016-01-01

, the effects of floor covering resistance on the whole system performance were studied using two heat sources; a natural gas fired condensing boiler and an air-source heat pump. The heating systems were also compared in terms of auxiliary exergy use for pumps and fans. The low temperature floor heating system......Three space heating systems (floor heating with different floor covering resistances, radiator heating with different working temperatures, warm-air heating with and without heat recovery) were compared using a natural gas fired condensing boiler as the heat source. For the floor heating systems...... performed better than other systems in terms of exergy demand. The use of boiler as a heat source for a low-exergy floor heating system creates a mismatch in the exergy supply and demand. Although an air-source heat pump could be a better heat source, this depends on the origin of the electricity supplied...

Energetic and financial evaluation of solar assisted heat pump space heating systems

International Nuclear Information System (INIS)

Bellos, Evangelos; Tzivanidis, Christos; Moschos, Konstantinos; Antonopoulos, Kimon A.

2016-01-01

Highlights: • Four solar heating systems are presented in this work. • Various combinations between solar collectors and heat pumps are presented. • The systems are compared energetically and financially. • The use of PV and an air source heat pump is the best choice financially. • The use of PVT with a water source heat pump is the best solution energetically. - Abstract: Using solar energy for space heating purposes consists an alternative way for substituting fossil fuel and grid electricity consumption. In this study, four solar assisted heat pump heating systems are designed, simulated and evaluated energetically and financially in order to determine the most attractive solution. The use of PV collectors with air source heat pump is compared to the use of FPC, PVT and FPC with PV coupled with a water source heat pump. A sensitivity analysis for the electricity cost is conducted because of the great variety of this parameter over the last years. The final results proved that for electricity cost up to 0.23 €/kW h the use of PV coupled with an air source heat pump is the most sustainable solution financially, while for higher electricity prices the coupling of PVT with an water source heat pump is the best choice. For the present electricity price of 0.2 €/kW h, 20 m"2 of PV is able to drive the air source heat pump with a yearly solar coverage of 67% leading to the most sustainable solution. Taking into account energetic aspects, the use of PVT leads to extremely low grid electricity consumption, fact that makes this technology the most environmental friendly.

Design of annual storage solar space heating systems

Energy Technology Data Exchange (ETDEWEB)

Hooper, F C; Cook, J D

1979-11-01

Design considerations for annual storage solar space heating systems are discussed. A simulation model for the performance of suh systems is described, and a method of classifying system configurations is proposed. It is shown that annual systems sized for unconstrained performance, with no unused collector or storage capacity, and no rejected heat, minimize solar acquisition costs. The optimal performance corresponds to the condition where the marginal storage-to-collector sizing ratio is equal to the corresponding marginal cost ratio.

Active charge, passive discharge floor space heating system

Energy Technology Data Exchange (ETDEWEB)

Salt, H.; Mahoney, K.J.

1987-01-01

This space heating system has a rockbed beneath and in contact with the floor of a dwelling, which is heated by radiation and convection from the floor. The ability of the heating system to maintain comfort conditions with no additional energy input is discussed and it is shown that the system is more suitable for use in mild climates than severe ones. Experimental work on horizontal air flow rockbeds is reported and shows that shallow beds can be designed in the same way as vertical air flow beds. The influence of natural convection on the effective thermal conductivity of the experimental rockbeds is reported.

Benefits and well-being perceived by green spaces users during heat waves

Directory of Open Access Journals (Sweden)

Dentamaro I

2010-07-01

Full Text Available In urban environments, green spaces have proven to act as ameliorating factors of some climatic features related to heat stress, reducing their effects and providing comfortable outdoor settings for people. In addition, green spaces have demonstrated greater capacity, compared with built-up areas, for promoting human health and well-being. In this paper, we present results of a study conducted in Italy with the general goal to contribute to the theoretical and empirical rationale for linking green spaces with well-being in urban environments. Specifically, the study focused on the physical and psychological benefits and the general well-being associated with the use of green spaces on people when heat stress episodes are more likely to occur. A questionnaire was set up and administered to users of selected green spaces in Italy (metropolitan area of Milan and Bari - n=400. Results indicate that longer and frequent visits of green spaces generate significant improvements of the perceived benefits and well-being among users. These results are consistent with the idea that the use of green spaces could alleviate the perception of thermal discomfort during periods of heat stress.

Convection heat transfer of closely-spaced spheres with surface blowing

Energy Technology Data Exchange (ETDEWEB)

Kleinstreuer, C. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering); Chiang, H. (Thermofluid Technology Div., Industrial Technology Research Inst., Chutung (Taiwan, Province of China))

1993-05-01

A validated computer simulation model has been developed for the analysis of colinear spheres in a heated gas stream. Using the Galerkin finite element method, the steady-state Navier-Stokes and heat transfer equations have been solved describing laminar axisymmetric thermal flow past closely-spaced monodisperse spheres with fluid injection. Of interest are the coupled nonlinear interaction effects on the temperature fields and ultimately on the Nusselt number of each sphere for different free stream Reynolds numbers (20 [<=] Re [<=] 200) and intersphere distances (1.5 [<=] d[sub ij] [<=] 6.0) in the presence of surface blowing (0 [<=] v[sub b] [<=] 0.1). Fluid injection (i.e. blowing) and associated wake effects generate lower average heat transfer coefficients for each interacting sphere when the Reynolds number increases (Re > 100). Heat transfer is also reduced at small spacings especially for the second and third sphere. A Nusselt number correlation for each interacting (porous) sphere has been developed based on computer experiments. (orig.)

Retrofitting Combined Space and Water Heating Systems: Laboratory Tests

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B.; Bohac, D.; Huelman, P.; Olson, R.; Hewitt, M.

2012-10-01

Better insulated and tighter homes can often use a single heating plant for both space and domestic water heating. These systems, called dual integrated appliances (DIA) or combination systems, can operate at high efficiency and eliminate combustion safety issues associated by using a condensing, sealed combustion heating plant. Funds were received to install 400 DIAs in Minnesota low-income homes. The NorthernSTAR DIA laboratory was created to identify proper system components, designs, operating parameters, and installation procedures to assure high efficiency of field installed systems. Tests verified that heating loads up to 57,000 Btu/hr can be achieved with acceptable return water temperatures and supply air temperatures.

Retrofitting Combined Space and Water Heating Systems. Laboratory Tests

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernStar Building America Partnership, St. Paul, MN (United States); Bohac, D. [NorthernStar Building America Partnership, St. Paul, MN (United States); Huelman, P. [NorthernStar Building America Partnership, St. Paul, MN (United States); Olsen, R. [NorthernStar Building America Partnership, St. Paul, MN (United States); Hewett, M. [NorthernStar Building America Partnership, St. Paul, MN (United States)

2012-10-01

Better insulated and tighter homes can often use a single heating plant for both space and domestic water heating. These systems, called dual integrated appliances (DIA) or combination systems, can operate at high efficiency and eliminate combustion safety issues associated by using a condensing, sealed combustion heating plant. Funds were received to install 400 DIAs in Minnesota low-income homes. The NorthernSTAR DIA laboratory was created to identify proper system components, designs, operating parameters, and installation procedures to assure high efficiency of field installed systems. Tests verified that heating loads up to 57,000 Btu/hr can be achieved with acceptable return water temperatures and supply air temperatures.

Investigation and assessment of wall heat transfer correlations in SPACE code

International Nuclear Information System (INIS)

Kim, Jung Woo; Kim, Kyung Doo; Moon, Sang Ki; Choi, Ki Yong; Park, Hyun Sik

2010-06-01

SPACE, which is a safety analysis code for nuclear power plants, has been developed to analyze the multidimensional, two-component and three-field flow. This code can be applied to safety analysis for approval which is thermal-hydraulic analysis to support the nuclear power station design, establishment of accident ease strategy, development of operating guide line, experiment plan and analysis. To do so, SPACE code has 12 wall heat transfer mode and the corresponding models and correlations to deal with the physical heat transfer phenomenon in wall surface. In this report, the physical correlation models regarding the wall heat transfer are explained and their performance is assessed against several SET

Experimental Studies on Grooved Double Pipe Heat Exchanger with Different Groove Space

Science.gov (United States)

Sunu, P. W.; Arsawan, I. M.; Anakottapary, D. S.; Santosa, I. D. M. C.; Yasa, I. K. A.

2018-01-01

Experimental studies were performed on grooved double pipe heat exchanger (DPHE) with different groove space. The objective of this work is to determine optimal heat transfer parameter especially logarithmic mean temperature difference (LMTD). The document in this paper also provides the total heat observed by the cold fluid. The rectangular grooves were incised on outer surface of tube side with circumferential pattern and two different grooves space, namely 1 mm and 2 mm. The distance between grooves and the grooves high were kept constant, 8 mm and 0.3 mm respectively. The tube diameter is 20 mm and its made of aluminium. The shell is made of acrylic which has 28 mm in diameter. Water is used as the working fluid. Using counter flow scheme, the cold fluid flows in the annulus room of DPHE. The volume flowrate of hot fluid remains constant at 15 lpm. The volume flowrate of cold fluid were varied from 11 lpm to 15 lpm. Based on logarithmic mean temperature difference analysis, the LMTD of 1 mm grooves space was higher compared to that of 2 mm grooves space. The smaller grooves space has more advantage since the recirculating region are increased which essentially cause larger heat transfer enhancement.

Space qualification of high capacity grooved heat pipes

Energy Technology Data Exchange (ETDEWEB)

Dubois, M; Mullender, B; Druart, J [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W; Beddows, A [ESTEC-The (Netherlands)

1997-12-31

Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

Space qualification of high capacity grooved heat pipes

Energy Technology Data Exchange (ETDEWEB)

Dubois, M.; Mullender, B.; Druart, J. [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W.; Beddows, A. [ESTEC-The (Netherlands)

1996-12-31

Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

Measure Guideline: Combined Space and Water Heating Installation and Optimization

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, St. Paul, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, St. Paul, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, St. Paul, MN (United States)

2017-03-01

Combined space and water heater (combi or combo) systems are defined by their dual functionality. Combi systems provide both space heating and water heating capabilities with a single heat source. This guideline will focus on the installation and operation of residential systems with forced air heating and domestic hot water (DHW) functionality. Past NorthernSTAR research has used a combi system to replace a natural gas forced air distribution system furnace and tank type water heater (Schoenbauer et al. 2012; Schoenbauer, Bohac, and McAlpine 2014). The combi systems consisted of a water heater or boiler heating plant teamed with a hydronic air handler that included an air handler, water coil, and water pump to circulate water between the heating plant and coil. The combi water heater or boiler had a separate circuit for DHW. Past projects focused on laboratory testing, field characterization, and control optimization of combi systems. Laboratory testing was done to fully characterize and test combi system components; field testing was completed to characterize the installed performance of combi systems; and control methodologies were analyzed to understand the potential of controls to simplify installation and design and to improve system efficiency and occupant comfort. This past work was relied upon on to create this measure guideline.

Measure Guideline: Combined Space and Water Heating Installation and Optimization

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Bohac, D. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

2017-03-03

Combined space and water heater (combi or combo) systems are defined by their dual functionality. Combi systems provide both space heating and water heating capabilities with a single heat source. This guideline will focus on the installation and operation of residential systems with forced air heating and domestic hot water (DHW) functionality. Past NorthernSTAR research has used a combi system to replace a natural gas forced air distribution system furnace and tank type water heater (Schoenbauer et al. 2012; Schoenbauer, Bohac, and McAlpine 2014). The combi systems consisted of a water heater or boiler heating plant teamed with a hydronic air handler that included an air handler, water coil, and water pump to circulate water between the heating plant and coil. The combi water heater or boiler had a separate circuit for DHW. Past projects focused on laboratory testing, field characterization, and control optimization of combi systems. Laboratory testing was done to fully characterize and test combi system components; field testing was completed to characterize the installed performance of combi systems; and control methodologies were analyzed to understand the potential of controls to simplify installation and design and to improve system efficiency and occupant comfort. This past work was relied upon on to create this measure guideline.

Performance predictions and measurements for space-power-system heat pipes

International Nuclear Information System (INIS)

Prenger, F.C. Jr.

1981-01-01

High temperature liquid metal heat pipes designed for space power systems have been analyzed and tested. Three wick designs are discussed and a design rationale for the heat pipe is provided. Test results on a molybdenum, annular wick heat pipe are presented. Performance limitations due to boiling and capillary limits are presented. There is evidence that the vapor flow in the adiabatic section is turbulent and that the transition Reynolds number is 4000

Heat-electricity convertion systems for a Brazilian space micro nuclear reactor

Energy Technology Data Exchange (ETDEWEB)

Guimaraes, Lamartine N.F.; Marcelino, Natalia B.; Placco, Guilherme M.; Nascimento, Jamil A.; Borges, Eduardo M., E-mail: guimarae@ieav.cta.br, E-mail: lamartine.guimaraes@pq.cnpq.br, E-mail: jamil@ieav.cta.br, E-mail: jalnsgf@outlook.com, E-mail: borges.em@hotmail.com, E-mail: ecorborges@hotmail.com, E-mail: ivayolini@gmail.com, E-mail: guilherme_placco@ig.com.br [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil); Barrios Junior, Ary Garcia, E-mail: arygarcia89@yahoo.com [Faculdade de Tecnologia Sao Francisco (FATESF), Jacarei, SP (Brazil)

2013-07-01

This contribution will discuss the evolution work in the development of thermal cycles to allow the development of heat-electricity conversion for the Brazilian space micro nuclear Reactor. Namely, innovative core and nuclear fuel elements, Brayton cycle, Stirling engine, heat pipes, passive multi-fluid turbine, among others. This work is basically to set up the experimental labs that will allow the specification and design of the space equipment. Also, some discussion of the cost so far, and possible other applications will be presented. (author)

Heat-electricity convertion systems for a Brazilian space micro nuclear reactor

International Nuclear Information System (INIS)

Guimaraes, Lamartine N.F.; Marcelino, Natalia B.; Placco, Guilherme M.; Nascimento, Jamil A.; Borges, Eduardo M.; Barrios Junior, Ary Garcia

2013-01-01

This contribution will discuss the evolution work in the development of thermal cycles to allow the development of heat-electricity conversion for the Brazilian space micro nuclear Reactor. Namely, innovative core and nuclear fuel elements, Brayton cycle, Stirling engine, heat pipes, passive multi-fluid turbine, among others. This work is basically to set up the experimental labs that will allow the specification and design of the space equipment. Also, some discussion of the cost so far, and possible other applications will be presented. (author)

Potential application of glazed transpired collectors to space heating in cold climates

International Nuclear Information System (INIS)

Gao, Lixin; Bai, Hua; Mao, Shufeng

2014-01-01

Highlights: • A mathematical model for glazed transpired collectors (GTC) is developed. • Glazing results in optical loss, but it decreases convective heat loss effectively. • Thermal performance of GTC shows considerable improvement on flat-plate collectors. • GTC using recirculated air is applicable to space heating in cold climates. - Abstract: Although unglazed transpired collectors (UTC) succeed in industrial ventilation applications, solar fraction is very low when they are used in space heating in cold climates due to the lower exit air temperature. Considering the potential for glazed transpired collectors (GTC) using recirculated air for space heating applications in cold climates, a mathematical model is developed for predicting the thermal performance of GTC. Simulation results show that although glazing results in optical loss, it could decrease convective heat loss resulted from high crosswind velocities effectively. For a solar radiation of 400 W/m 2 , an ambient temperature of −10 °C, and a suction velocity of 0.01 m/s, the exit air temperature of GTC is higher than that of UTC for crosswind velocities exceeding 3.0 m/s. By comparison with a conventional flat-plate solar air collector operating under the same conditions, the thermal performance of GTC shows a significant improvement. For a five-storey hotel building located in the severe cold climate zone of China, case study shows that the annual solar fraction of the GTC-based solar air heating system is about 20%, which is two times higher than that of the flat-plate collector-based system and nearly nine times higher than that of the UTC-based system respectively. Hence, an enormous amount of energy will be saved with the application of GTC to space heating in cold climates

A heat receiver design for solar dynamic space power systems

Science.gov (United States)

Baker, Karl W.; Dustin, Miles O.; Crane, Roger

1990-01-01

An advanced heat pipe receiver designed for a solar dynamic space power system is described. The power system consists of a solar concentrator, solar heat receiver, Stirling heat engine, linear alternator and waste heat radiator. The solar concentrator focuses the sun's energy into a heat receiver. The engine and alternator convert a portion of this energy to electric power and the remaining heat is rejected by a waste heat radiator. Primary liquid metal heat pipes transport heat energy to the Stirling engine. Thermal energy storage allows this power system to operate during the shade portion of an orbit. Lithium fluoride/calcium fluoride eutectic is the thermal energy storage material. Thermal energy storage canisters are attached to the midsection of each heat pipe. The primary heat pipes pass through a secondary vapor cavity heat pipe near the engine and receiver interface. The secondary vapor cavity heat pipe serves three important functions. First, it smooths out hot spots in the solar cavity and provides even distribution of heat to the engine. Second, the event of a heat pipe failure, the secondary heat pipe cavity can efficiently transfer heat from other operating primary heat pipes to the engine heat exchanger of the defunct heat pipe. Third, the secondary heat pipe vapor cavity reduces temperature drops caused by heat flow into the engine. This unique design provides a high level of reliability and performance.

Energetical and ecological assessment of solar- and heat pump technologies for hot water preparation and space heating in Austria

International Nuclear Information System (INIS)

Faninger, G.

1991-11-01

Solar and heat pump systems have been proved in many applications on the market. To achieve an efficient energy output it is necessary to consider the special conditions of these technologies. The energetical and ecological criteria of solar and heat pump systems for hot water preparation and space heating are analysed on the basis of experimental data. (author)

Solar Space and Water Heating for School -- Dallas, Texas

Science.gov (United States)

1982-01-01

90 page report gives overview of retrofitted solar space-heating and hot-water system installation for 61-year-old high school. Description, specifications, modifications, plan drawings for roof, three floors, basement, correspondence, and documents are part of report.

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.

Combined Space and Water Heating: Next Steps to Improved Performance

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

2016-07-13

A combined space- and water-heating (combi) system uses a high-efficiency direct-vent burner that eliminates safety issues associated with natural draft appliances. Past research with these systems shows that using condensing water heaters or boilers with hydronic air handling units can provide both space and water heating with efficiencies of 90% or higher. Improved controls have the potential to reduce complexity and improve upon the measured performance. This project demonstrates that controls can significantly benefit these first-generation systems. Laboratory tests and daily load/performance models showed that the set point temperature reset control produced a 2.1%-4.3% (20-40 therms/year) savings for storage and hybrid water heater combi systems operated in moderate-load homes.

Effect of the inter-block spacing on the thermal performance of a PCM based heat sink

Energy Technology Data Exchange (ETDEWEB)

Faraji, M.; El Qarnia, H. [Cadi Ayyad Univ., Marrakech (Morocco). Faculte des sciences Semlalia, Dept. de physique, Laboratoire de mecanique des fluides et d' energetique; El Khadir, L. [Cadi Ayyad Univ., Marrakech (Morocco). Faculte des sciences Semlalia, Dept. de physique, Laboratoire d' tomatique de l' Environnement et Procedes de Transferts

2010-07-01

Advanced electronic devices require efficient thermal control systems. Heat transfer analysis of such systems is challenging because of constraints regarding space limitations, power consumption and noise level. This study considered the problem of melting and natural convection in a rectangular enclosure heated with 3 heat sources with a constant and uniform volumetric heat generation. The heat sources were protruding and mounted on a vertical conducting plate. Conjugate conduction in a plate and heat sources coupled with natural convection and melting process were examined in an effort to determine the effects of the inter-blocks spacing ratio on the thermal performance of the cooling PCM-heat sink. The percentage contribution of substrate heat conduction on the total removed heat from heat sources was also investigated. Correlations were derived for the non- dimensional secured working time and the corresponding melt fraction. In order to investigate the thermal behaviour of the proposed heat sink, a mathematical model was developed based on the mass, momentum and energy conservation equations. The results revealed that for lower inter-blocks spacing, the dimensionless secured working time needed by the chips to reach the critical temperature was maximized. The highest inter-blocks spacing ratio provoked a sudden rise in chip temperatures and thus reduced the dimensionless secured working time. It was concluded that this approach can be used in the design of PCM-based cooling systems. 9 refs., 2 tabs., 4 figs.

Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

Energy Technology Data Exchange (ETDEWEB)

Kingston, T. [Gas Technology Inst., Des Plaines, IL (United States); Scott, S. [Gas Technology Inst., Des Plaines, IL (United States)

2013-03-01

Homebuilders are exploring more cost-effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads and found that the tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system, among other key findings.

Determinants of residential space heating expenditures in Great Britain

Energy Technology Data Exchange (ETDEWEB)

Meier, Helena [Department of Economics, University of Hamburg, Von Melle Park 5, 20146 Hamburg (Germany); Rehdanz, Katrin [Department of Economics, University of Kiel, Olshausenstrasse 40, 24118 Kiel (Germany)

2010-09-15

In Great Britain, several policy measures have been implemented in order to increase energy efficiency and reduce carbon emissions. In the domestic sector, this could, for example, be achieved by improving space heating efficiency and thus decreasing heating expenditure. However, in order to efficiently design and implement such policy measures, a better understanding of the determinants affecting heating expenditure is needed. In this paper we examine the following determinants: socio-economic factors, building characteristics, heating technologies and weather conditions. In contrast to most other studies we use panel data to investigate household demand for heating in Great Britain. Our data sample is the result of an annual set of interviews with more than 5000 households, starting in 1991 and ending in 2005. The sample represents a total of 64,000 observations over the fifteen-year period. Our aim is to derive price and income elasticities both for Britain as a whole and for different types of household. Our results suggest that differences exist between owner-occupied and renter households. These households react differently to changes in income and prices. Our results also imply that a number of socio-economic criteria have a significant influence on heating expenditure, independently of the fuel used for heating. Understanding the impacts of different factors on heating expenditure and impact differences between types of household is helpful in designing target-oriented policy measures. (author)

Self-rewetting carbon nanofluid as working fluid for space and terrestrial heat pipes

Science.gov (United States)

Di Paola, R.; Savino, R.; Mirabile Gattia, D.; Marazzi, R.; Vittori Antisari, M.

2011-11-01

Thermal management is very important in modern electronic systems. Recent researches have been dedicated to the study of the heat transfer performances of binary heat transfer fluids with peculiar surface tension properties and in particular to that of "self-rewetting fluids", i.e., liquids with a surface tension increasing with temperature and concentration. Since in the course of liquid/vapor-phase change, self-rewetting fluids behavior induces a rather strong liquid inflow (caused by both temperature and concentration gradients) from the cold region (where liquid condensates) to the hot evaporator region, this fluids have been proposed and investigated as new heat transfer fluids for advanced heat transfer devices, e.g., heat pipes or heat spreaders for terrestrial and space applications (Savino et al. in Space Technol 25(1):59-61, 2009). The present work is dedicated to the study of the thermophysical properties of a new class of heat transfer fluids based on water/alcohol solutions with suspended carbon nanostructures, in particular single-wall carbon nanohorns (SWNH), synthesized by a homemade apparatus with an AC arc discharge in open air (Mirabile Gattia et al. in Nanotechnology 18:255604, 2007). SWNHs are cone-shaped nanoparticles with diameters between 1 and 5 nm and lengths in the range of 20-100 nm. SWNHs could be found in the form of quite-spherical aggregates with diameters ranging from 20 to 100 nm. The paper also discusses the results of these investigations and laboratory characterization tests of different heat pipes, including reference ordinary heat pipes and innovative pipes filled with self-rewetting fluids and self-rewetting nanofluids. The potential interest of the proposed studies stems from the large number of possible industrial applications, including space technologies and terrestrial applications, such as cooling of electronic components.

Self-rewetting carbon nanofluid as working fluid for space and terrestrial heat pipes

International Nuclear Information System (INIS)

Di Paola, R.; Savino, R.; Mirabile Gattia, D.; Marazzi, R.; Vittori Antisari, M.

2011-01-01

Thermal management is very important in modern electronic systems. Recent researches have been dedicated to the study of the heat transfer performances of binary heat transfer fluids with peculiar surface tension properties and in particular to that of “self-rewetting fluids”, i.e., liquids with a surface tension increasing with temperature and concentration. Since in the course of liquid/vapor-phase change, self-rewetting fluids behavior induces a rather strong liquid inflow (caused by both temperature and concentration gradients) from the cold region (where liquid condensates) to the hot evaporator region, this fluids have been proposed and investigated as new heat transfer fluids for advanced heat transfer devices, e.g., heat pipes or heat spreaders for terrestrial and space applications (Savino et al. in Space Technol 25(1):59–61, 2009). The present work is dedicated to the study of the thermophysical properties of a new class of heat transfer fluids based on water/alcohol solutions with suspended carbon nanostructures, in particular single-wall carbon nanohorns (SWNH), synthesized by a homemade apparatus with an AC arc discharge in open air (Mirabile Gattia et al. in Nanotechnology 18:255604, 2007). SWNHs are cone-shaped nanoparticles with diameters between 1 and 5 nm and lengths in the range of 20–100 nm. SWNHs could be found in the form of quite-spherical aggregates with diameters ranging from 20 to 100 nm. The paper also discusses the results of these investigations and laboratory characterization tests of different heat pipes, including reference ordinary heat pipes and innovative pipes filled with self-rewetting fluids and self-rewetting nanofluids. The potential interest of the proposed studies stems from the large number of possible industrial applications, including space technologies and terrestrial applications, such as cooling of electronic components.

Microeconomics and the demand for space heating

Energy Technology Data Exchange (ETDEWEB)

Fisk, D.J.

1977-12-01

The techniques of economic utility theory are combined with the technical equations for heat loss from a dwelling to give insight into the variation of consumer demand for space heating. A theoretical relationship is established between the performance of the occupied dwelling as the external temperature falls and the short-run income elasticity of energy demand. The analysis is applied to studies of UK heating practice in the 1950s and the implied indifference map for thermal comfort deduced. This indifference map is found to show a considerable economic propensity to absorb some of the potential savings from energy conservation measurements in higher internal temperatures. The effect found is sufficiently large to have consequences for future energy planning if it were still present in the UK domestic sector. The analysis highlights a number of points that should aid the interpretation of field experiments on domestic energy consumption. In particular, it is shown that unless great care is taken to separate out the technical and economic origins of internal temperature variation, the results of field studies on the effectiveness of conservation techniques may only be of shortlived value.

Space shuttle/food system study. Volume 2, Appendix A: Active heating system-screening analysis. Appendix B: Reconstituted food heating techniques analysis

Science.gov (United States)

1974-01-01

Technical data are presented which were used to evaluate active heating methods to be incorporated into the space shuttle food system design, and also to evaluate the relative merits and penalties associated with various approaches to the heating of rehydrated food during space flight. Equipment heating candidates were subject to a preliminary screening performed by a selection rationale process which considered the following parameters; (1) gravitational effect; (2) safety; (3) operability; (4) system compatibility; (5) serviceability; (6) crew acceptability; (7) crew time; (8) development risk; and (9) operating cost. A hot air oven, electrically heated food tray, and microwave oven were selected for further consideration and analysis. Passive, semi-active, and active food preparation approaches were also studied in an effort to determine the optimum method for heating rehydrated food. Potential complexity, cost, vehicle impact penalties, and palatability were considered in the analysis. A summary of the study results is provided along with cost estimates for each of the potential sytems

Thin film heat flux sensor for Space Shuttle Main Engine turbine environment

Science.gov (United States)

Will, Herbert

1991-01-01

The Space Shuttle Main Engine (SSME) turbine environment stresses engine components to their design limits and beyond. The extremely high temperatures and rapid temperature cycling can easily cause parts to fail if they are not properly designed. Thin film heat flux sensors can provide heat loading information with almost no disturbance of gas flows or of the blade. These sensors can provide steady state and transient heat flux information. A thin film heat flux sensor is described which makes it easier to measure small temperature differences across very thin insulating layers.

Utilising heat from nuclear waste for space heating

International Nuclear Information System (INIS)

Deacon, D.

1982-01-01

A heating unit utilising the decay heat from irradiated material comprises a storage envelope for the material associated with a heat exchange system, means for producing a flow of air over the heat exchange system to extract heat from the material, an exhaust duct capable of discharging the heated air to the atmosphere, and means for selectively diverting at least some of the heated air to effect the required heating. With the flow of air over the heat exchange system taking place by a natural thermosyphon process the arrangement is self regulating and inherently reliable. (author)

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

Critical evaluation of molybdenum and its alloys for use in space reactor core heat pipes

International Nuclear Information System (INIS)

Lundberg, L.B.

1981-01-01

The choice of pure molybdenum as the prime candidate material for space reactor core heat pipes is examined, and the advantages and disadvantages of this material are brought into focus. Even though pure molybdenum heat pipes have been built and tested, this metal's high ductile-brittle transition temperature and modest creep strength place significant design restrictions on a core heat pipe made from it. Molybdenum alloys are examined with regard to their promise as potential replacements for pure molybdenum. The properties of TZM and molybdenum-rhenium alloys are examined, and it appears that Mo-Re alloys with 10 to 15 wt % rhenium offer the most advantage as an alternative to pure molybdenum in space reactor core heat pipes

Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

Energy Technology Data Exchange (ETDEWEB)

Kingston, T.; Scott, S.

2013-03-01

Homebuilders are exploring more cost effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads with the following key findings: 1) The tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system. 2) The tankless combo system consistently achieved better daily efficiencies (i.e. 84%-93%) than the storage combo system (i.e. 81%- 91%) when the air handler was sized adequately and adjusted properly to achieve significant condensing operation. When condensing operation was not achieved, both systems performed with lower (i.e. 75%-88%), but similar efficiencies. 3) Air handlers currently packaged with combo systems are not designed to optimize condensing operation. More research is needed to develop air handlers specifically designed for condensing water heaters. 4) System efficiencies greater than 90% were achieved only on days where continual and steady space heating loads were required with significant condensing operation. For days where heating was more intermittent, the system efficiencies fell below 90%.

Development and test of a space-reactor-core heat pipe

International Nuclear Information System (INIS)

Merrigan, M.A.; Runyan, J.E.; Martinez, H.E.; Keddy, E.S.

1983-01-01

A heat pipe designed to meet the heat transfer requirements of a 100-kW/sub e/ space nuclear power system has been developed and tested. General design requirements for the device included an operating temperature of 1500 0 K with an evaporator radial flux density of 100 w/cm 2 . The total heat-pipe length of 2 m comprised an evaporator length of 0.3 m, a 1.2-m adiabatic section, and a condenser length of 0.5 m. A four-artery design employing screen arteries and distribution wicks was used with lithium serving as the working fluid. Molybdenum alloys were used for the screen materials and tube shell. Hafnium and zirconium gettering materials were used in connection with a pre-purified distilled lithium charge to ensure internal chemical compatibility. After initial performance verification, the 14.1-mm i.d. heat pipe was operated at 15 kW throughput at 1500 0 K for 100 hours. No performance degradation was observed during the test

Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant; Kombineret brugsvands- og rumvarmepumpe med CO{sub 2} som koelemiddel

Energy Technology Data Exchange (ETDEWEB)

Schoen Poulsen, C. [Teknologisk Institut (Denmark)

2006-05-19

This project report describes the implementation of the Danish project called 'Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant'. In the course of the project, a combined heat pump has been developed for heating sanitary hot water and producing domestic space heating. The project shows that CO2 has excellent properties in systems where a high temperature is desired on the gas cooler side and that it is possible to combine the production of sanitary hot water with the production of domestic space heating. During the project, a number of system solutions have been analysed and at the end of the project a prototype was built. It was tested in the laboratory according to a current Dutch standard for heat pumps for sanitary hot water. The prototype was constructed without the space heat part which solely has been analysed according to calculations. The reason is that there currently are no applicable European standards for the testing of combined systems and as the total efficiency of the system mainly depends on the temperature out of the gas cooler it was decided not to spend resources on the construction of the combined system in the prototype version of the unit. Instead, a number of proposals have been submitted to how the system with a space heat section could be constructed. The main components used in the prototype (compressor, exchangers, valve, control and tank) are all partly commercially available and therefore focus has been on the system construction. During the project, a number of CFD calculations have been carried out on the gas cooler in the hot water tank and the results show how important it is that the gas cooler is designed and placed correctly. The laboratory tests carried out on the unit show that the COP of the heat pump plant in connection with sanitary hot water tapping (according to Dutch standard) is 1.4 1.5 which is not immediately satisfactory. But when it is considered that the unit is a

Thermal performance analysis of a phase change thermal storage unit for space heating

Energy Technology Data Exchange (ETDEWEB)

Halawa, E.; Saman, W. [Institute for Sustainable Systems and Technologies School of Advanced Manufacturing and Mechanical Engineering, University of South Australia, Mawson Lakes SA 5095 (Australia)

2011-01-15

This paper presents the results of a comprehensive numerical study on the thermal performance of an air based phase change thermal storage unit (TSU) for space heating. The unit is designed for integration into space heating and cooling systems. The unit consists of a number of one dimensional phase change material (PCM) slabs contained in a rectangular duct where air passes between the slabs. The numerical analysis was based on an experimentally validated model. A parametric study has been carried out including the study on the effects of charge and discharge temperature differences, air mass flow rate, slab thicknesses, air gaps and slab dimensions on the air outlet temperatures and heat transfer rates of the thermal storage unit. The paper introduces and discusses quantities called charge and discharge temperature differences which play an important role in the melting and freezing processes. (author)

Conceptual Design of a Condensing Heat Exchanger for Space Systems Using Porous Media

Science.gov (United States)

Hasan, Mohammad M.; Khan, Lutful I.; Nayagam, Vedha; Balasubramaniam, Ramaswamy

2006-01-01

Condensing heat exchangers are used in many space applications in the thermal and humidity control systems. In the International Space Station (ISS), humidity control is achieved by using a water cooled fin surface over which the moist air condenses, followed by "slurper bars" that take in both the condensate and air into a rotary separator and separates the water from air. The use of a cooled porous substrate as the condensing surface provides and attractive alternative that combines both heat removal as well as liquid/gas separation into a single unit. By selecting the pore sizes of the porous substrate a gravity independent operation may also be possible with this concept. Condensation of vapor into and on the porous surface from the flowing air and the removal of condensate from the porous substrate are the critical processes involved in the proposed concept. This paper describes some preliminary results of the proposed condensate withdrawal process and discusses the on-going design and development work of a porous media based condensing heat exchanger at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Dynamic simulation of space heating systems with radiators controlled by TRVs in buildings

Energy Technology Data Exchange (ETDEWEB)

Xu, Baoping; Fu, Lin; Di, Hongfa [Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084 (China)

2008-07-01

The objective of this paper is to develop a model for simulating the thermal and hydraulic behavior of space heating systems with radiators controlled by thermostat valves (TRVs) in multi-family buildings. This is done by treating the building and the heating system as a complete entity. Sub-models for rooms, radiators, TRVs, and the hydraulic network are derived. Then the suggested sub-models are combined to form an integrated model by considering interactions between them. The proposed model takes into account the heat transfer between neighboring rooms, the transport delay in the radiator, the self-adjusting function of the TRV, and the consumer's regulation behavior, as well as the hydraulic interactions between consumers. To test the model, two space heating systems in Beijing and Tianjin were investigated, and the model was validated under three operation modes. There was good agreement between the measured and simulated values for room temperature, return water temperature, and flow rate. A modeling analysis case was given based on an existing building and heating system. It was found that when the set value of the TRVs were kept on 2-3, about 12.4% reduction of heat consumption could be gained, compared with the situation in which the TRVs were kept fully open. The water flow rate was an important index that truly reflected the heat load change. It was also noted that if the flow rate or supply water temperature changed much during the transport delay time in the radiator, ignoring the transport delay would introduce an obvious deviation of the simulation results. Additionally, when an apartment stopped using the heating system during a heating season, the heat consumption of its neighboring apartments would be increased about 6-14%. (author)

The Liquid Droplet Radiator - an Ultralightweight Heat Rejection System for Efficient Energy Conversion in Space

Science.gov (United States)

Mattick, A. T.; Hertzberg, A.

1984-01-01

A heat rejection system for space is described which uses a recirculating free stream of liquid droplets in place of a solid surface to radiate waste heat. By using sufficiently small droplets ( 100 micron diameter) of low vapor pressure liquids the radiating droplet sheet can be made many times lighter than the lightest solid surface radiators (heat pipes). The liquid droplet radiator (LDR) is less vulnerable to damage by micrometeoroids than solid surface radiators, and may be transported into space far more efficiently. Analyses are presented of LDR applications in thermal and photovoltaic energy conversion which indicate that fluid handling components (droplet generator, droplet collector, heat exchanger, and pump) may comprise most of the radiator system mass. Even the unoptimized models employed yield LDR system masses less than heat pipe radiator system masses, and significant improvement is expected using design approaches that incorporate fluid handling components more efficiently. Technical problems (e.g., spacecraft contamination and electrostatic deflection of droplets) unique to this method of heat rejectioon are discussed and solutions are suggested.

Green Space and Deaths Attributable to the Urban Heat Island Effect in Ho Chi Minh City.

Science.gov (United States)

Dang, Tran Ngoc; Van, Doan Quang; Kusaka, Hiroyuki; Seposo, Xerxes T; Honda, Yasushi

2018-04-01

To quantify heat-related deaths in Ho Chi Minh City, Vietnam, caused by the urban heat island (UHI) and explore factors that may alleviate the impact of UHIs. We estimated district-specific meteorological conditions from 2010 to 2013 using the dynamic downscaling model and calculated the attributable fraction and number of mortalities resulting from the total, extreme, and mild heat in each district. The difference in attributable fraction of total heat between the central and outer districts was classified as the attributable fraction resulting from the UHI. The association among attributable fraction, attributable number with a green space, population density, and budget revenue of each district was then explored. The temperature-mortality relationship between the central and outer areas was almost identical. The attributable fraction resulting from the UHI was 0.42%, which was contributed by the difference in temperature distribution between the 2 areas. Every 1-square-kilometer increase in green space per 1000 people can prevent 7.4 deaths caused by heat. Green space can alleviate the impacts of UHIs, although future studies conducting a heath economic evaluation of tree planting are warranted.

Ultra-Low Heat-Leak, High-Temperature Superconducting Current Leads for Space Applications

Science.gov (United States)

Rey, Christopher M.

2013-01-01

NASA Goddard Space Flight Center has a need for current leads used in an adiabatic demagnetization refrigerator (ADR) for space applications. These leads must comply with stringent requirements such as a heat leak of approximately 100 W or less while conducting up to 10 A of electric current, from more than 90 K down to 10 K. Additionally, a length constraint of leak leads currently to NASA's specs.

District space heating potential of low temperature hydrothermal geothermal resources in the southwestern United States. Technical report

Energy Technology Data Exchange (ETDEWEB)

McDevitt, P.K.; Rao, C.R.

1978-10-01

A computer simulation model (GIRORA-Nonelectric) is developed to study the economics of district space heating using geothermal energy. GIRORA-Nonelectric is a discounted cashflow investment model which evaluates the financial return on investment for space heating. This model consists of two major submodels: the exploration for and development of a geothermal anomaly by a geothermal producer, and the purchase of geothermal fluid by a district heating unit. The primary output of the model is a calculated rate of return on investment earned by the geothermal producer. The results of the sensitivity analysis of the model subject to changes in physical and economic parameters are given in this report. Using the results of the economic analysis and technological screening criteria, all the low temperature geothermal sites in Southwestern United States are examined for economic viability for space heating application. The methodology adopted and the results are given.

Measurement and analysis of SPS kicker magnet heating and outgassing with Different Bunch Spacing

CERN Document Server

Barnes, M J; Cornelis, K; Ducimetière, L; Mahner, E; Papotti, G; Rumolo, G; Senaj, V; Shaposhnikova, E

2010-01-01

Fast kicker magnets are used to inject beam into and eject beam out of the CERN SPS accelerator ring. These kickers are generally ferrite loaded transmission line type magnets with a rectangular shaped aperture through which the beam passes. Unless special precautions are taken the impedance of the ferrite yoke can provoke significant beam induced heating, over several hours, even above the Curie temperature of the ferrite. At present the nominal bunch spacing in the SPS is 25 ns, however for an early stage of LHC operation it is preferable to have 50 ns bunch spacing. Machine Development (MD) studies have been carried out with an inter-bunch spacing of 25 ns, 50 ns or 75 ns. For some of the SPS kicker magnets the 75 ns bunch spacing resulted in considerable beam induced heating. In addition the MDs showed that 50 ns bunch spacing could result in a very rapid pressure rise in the kicker magnet and thus cause an interlock. This paper discusses the MD observations of the SPS kickers and analyses the available d...

Energy efficiency policies for space heating in EU countries: A panel data analysis for the period 1990–2010

International Nuclear Information System (INIS)

Ó Broin, Eoin; Nässén, Jonas; Johnsson, Filip

2015-01-01

Highlights: • Space heating demand between 1990 and 2010 modelled using a panel of 14 EU countries. • The impacts of 260 efficiency polices affecting space heating demand are examined. • Regulatory policies found to have had a greater success than financial or informative. • High priority should be given to regulatory policies for space heating energy goals. - Abstract: We present an empirical analysis of the more than 250 space heating-focused energy efficiency policies that have been in force at the EU and national levels in the period 1990–2010. This analysis looks at the EU-14 residential sector (Pre-2004 EU-15, excluding Luxembourg) using a panel data regression analysis on unit consumption of energy for space heating (kWh/m 2 /year). The policies are represented as a regression variable using a semi-quantitative impact estimation obtained from the MURE Policy Database. The impacts of the policies as a whole, and subdivided into financial, regulatory, and informative policies, are examined. The correlation between the actual reductions in demand and the estimated impact of regulatory policies is found to be stronger than the corresponding correlations with the respective impacts of financial policies and informative polices. Together with the well-known market barriers to energy efficiency that exist in the residential sector, these findings suggest that regulatory policy measures be given a high priority in the design of an effective pathway towards the EU-wide goals for space heating energy

Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads

Directory of Open Access Journals (Sweden)

Monika Chmielowiec-Jablczyk

2018-02-01

Full Text Available A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the energy equation and the heat transfer equation are done iteratively with the finite volume method by considering a constant flow rate. Both effects—laminar/turbulent flow and centrifugal force—are considered. The calculation results are compared with measurements done for a flooded thrust bearing with nominal eight tilting pads with an outer diameter of 180 mm. The heat convection coefficients for the pad surfaces mainly influence the pad temperature field and are adjusted to the measurement results. In the following paper, the calculation results for variable space distances, influence of different parameters on the bearing behavior and operating condition at high load are presented.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Investigation of heat exchangers for energy conversion systems of megawatt-class space power plants

Science.gov (United States)

Ilmov, D. N.; Mamontov, Yu. N.; Skorohodov, A. S.; Smolyarov, V. A.; Filatov, N. I.

2016-01-01

The specifics of operation (high temperatures in excess of 1000 K and large pressure drops of several megapascals between "hot" and "cold" coolant paths) of heat exchangers in the closed circuit of a gasturbine power converter operating in accordance with the Brayton cycle with internal heat recovery are analyzed in the context of construction of space propulsion systems. The design of a heat-exchange matrix made from doubly convex stamped plates with a specific surface relief is proposed. This design offers the opportunity to construct heat exchangers with the required parameters (strength, rigidity, weight, and dimensions) for the given operating conditions. The diagram of the working area of a test bench is presented, and the experimental techniques are outlined. The results of experimental studies of heat exchange and flow regimes in the models of heat exchangers with matrices containing 50 and 300 plates for two pairs of coolants (gas-gas and gas-liquid) are detailed. A criterion equation for the Nusselt number in the range of Reynolds numbers from 200 to 20 000 is proposed. The coefficients of hydraulic resistance for each coolant path are determined as functions of the Reynolds number. It is noted that the pressure in the water path in the "gas-liquid" series of experiments remained almost constant. This suggests that no well-developed processes of vaporization occurred within this heat-exchange matrix design even when the temperature drop between gas and water was as large as tens or hundreds of degrees. The obtained results allow one to design flight heat exchangers for various space power plants.

A Data Analysis Approach for Diagnosing Malfunctioning in Domestic Space Heating

NARCIS (Netherlands)

Tabatabaei, S.

Around one third of worldwide energy usage is for the residential section and 60% of the energy consumption in this domestic area is for space heating. Therefore, monitoring and controlling this part of energy usage can have a major effect on the overall energy consumption and also on the emission

Competition in the market for space heating. District heating as the infrastructure for competition among fuels and technologies

International Nuclear Information System (INIS)

Grohnheit, Poul Erik; Gram Mortensen, Bent Ole

2003-01-01

None of the EU directives on liberalisation of the electricity and gas markets are considering the district heating systems, although the district heating networks offer the possibility of competition between natural gas and a range of other fuels on the market for space heating. Cogeneration of electricity and heat for industrial processes or district heating is a technology option for increased energy efficiency and thus reduction of CO 2 emissions. In the mid-1990s less than 10% of the electricity generation in the European Union was combined production with significant variations among Member States. These variations are explained by different national legislation and relative power of institutions, rather than difference in industrial structure, climate or urban physical structure. The 'single energy carrier' directives have provisions that support the development of combined heat and power (CHP), but they do not support the development and expansion of the district heating infrastructure. The article is partly based on a contribution to the Shared Analysis Project for the European Commission DG Energy, concerning the penetration of CHP, energy saving, and renewables as instruments to meet the targets of the Kyoto Protocol within the liberalised European energy market. The quantitative and legal differences of the heat markets in selected Member States are described, and the consequences of the directives are discussed. Finally, we summarise the tasks for a European policy concerning the future regulation of district heating networks for CHP, emphasising the need for rules for a fair competition between natural gas and district heating networks

Energy Efficiency and Sustainability Evaluation of Space and Water Heating in Urban Residential Buildings of the Hot Summer and Cold Winter Zone in China

Directory of Open Access Journals (Sweden)

Xiao Chen

2016-09-01

Full Text Available With the urbanization process of the hot summer and cold winter (HSCW zone in China, the energy consumption of space and water heating in urban residential buildings of the HSCW zone has increased rapidly. This study presents the energy efficiency and sustainability evaluation of various ways of space and water heating taking 10 typical cities in the HSCW zone as research cases. Two indicators, primary energy efficiency (PEE and sustainability index based on exergy efficiency, are adopted to perform the evaluation. Models for the energy and total exergy efficiencies of various space and water heating equipment/systems are developed. The evaluation results indicate that common uses of electricity for space and water heating are the most unsustainable ways of space and water heating. In terms of PEE and sustainability index, air-source heat pumps for space and water heating are suitable for the HSCW zone. The PEE and sustainability index of solar water heaters with auxiliary electric heaters are greatly influenced by local solar resources. Air-source heat pump assisted solar hot water systems are the most sustainable among all water heating equipment/systems investigated in this study. Our works suggest the key potential for improving the energy efficiency and the sustainability of space and water heating in urban residential buildings of the HSCW zone.

Decreasing of energy consumption for space heating in existing residential buildings; Combined geothermal and gas district heating systems

International Nuclear Information System (INIS)

Rosca, Marcel

2000-01-01

The City of Oradea, Romania, has a population of about 230 000 inhabitants. Almost 70% of the total heat demand, including industrial, is supplied by a classical East European type district heating system. The heat is supplied by two low grade coal fired co-generation power plants. The oldest distribution networks and substitutions, as well as one power plant, are 35 years old and require renovation or even reconstruction. The geothermal reservoir located under the city supplies at present 2,2% of the total heat demand. By generalizing the reinjection, the production can be increased to supply about 8% of the total heat demand, without any significant reservoir pressure or temperature decline over 25 years. Another potential energy source is natural gas, a main transport pipeline running close to the city. Two possible scenarios are envisaged to replace the low grade coal by natural gas and geothermal energy as heat sources for Oradea. In one scenario, the geothermal energy supplies the heat for tap water heating and the base load for space heating in a limited number of substations, with peak load being produced by natural gas fired boilers. In the other scenario, the geothermal energy is only used for tap water heating. In both scenarios, all substations are converted into heat plants, natural gas being the main energy source. The technical, economic, and environmental assessment of the two proposed scenarios are compared with each other, as well as with the existing district heating system. Two other possible options, namely to renovate and convert the existing co-generation power plants to natural gas fired boilers or to gas turbines, are only briefly discussed, being considered unrealistic, at least for the short and medium term future. (Author)

Field evaluation and assessment of thermal energy storage for residential space heating

Science.gov (United States)

Hersh, H. N.

1982-02-01

A data base was developed based on two heating seasons and 45 test and 30 control homes in Maine and Vermont. Based on first analysis of monitored temperatures and electrical energy used for space heating, fuel bills and reports of users and utilities, the technical performance of TES ceramic and hydronic systems is deemed to be technically satisfactory and there is a high degree of customer acceptance and positive attitudes towards TES. Analysis of house data shows a high degree of variability in electric heat energy demand for a given degree-day. An analysis is underway to investigate relative differences in the efficiency of electricity utilization of storage and direct heating devices. The much higher price of storge systems relative to direct systems is an impediment to market penetration. A changing picture of rate structures may encourage direct systems at the expense of storage systems.

Design package for a complete residential solar space heating and hot water system

Science.gov (United States)

1978-01-01

Information necessary to evaluate the design of a solar space heating and hot water system is reported. System performance specifications, the design data brochure, the system description, and other information pertaining to the design are included.

Practical versus theoretical domestic energy consumption for space heating

International Nuclear Information System (INIS)

Audenaert, A.; Briffaerts, K.; Engels, L.

2011-01-01

Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: → The energy advice procedure (EAP) calculates the energy use for heating in dwellings. → Calculations are compared with the real energy use for 5 dwellings. → A survey on the occupants' behaviour is used to interpret the observed differences. → Default values used in the EAP can be very different from the observed behaviour.

Practical versus theoretical domestic energy consumption for space heating

Energy Technology Data Exchange (ETDEWEB)

Audenaert, A., E-mail: amaryllis.audenaert@artesis.be [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium); Department of Environment, Technology and Technology Management, University of Antwerp, Prinsstraat 13, B-2000 Antwerp (Belgium); Briffaerts, K. [Unit Transition Energy and Environment, VITO NV, Boeretang 200, B-2400 Mol (Belgium); Engels, L. [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium)

2011-09-15

Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: > The energy advice procedure (EAP) calculates the energy use for heating in dwellings. > Calculations are compared with the real energy use for 5 dwellings. > A survey on the occupants' behaviour is used to interpret the observed differences. > Default values used in the EAP can be very different from the observed behaviour.

Large-size deployable construction heated by solar irradiation in free space

Science.gov (United States)

Pestrenina, Irena; Kondyurin, Alexey; Pestrenin, Valery; Kashin, Nickolay; Naymushin, Alexey

Large-size deployable construction in free space with subsequent direct curing was invented more than fifteen years ago (Briskman et al., 1997 and Kondyurin, 1998). It caused a lot of scientific problems, one of which is a possibility to use the solar energy for initiation of the curing reaction. This paper is devoted to investigate the curing process under sun irradiation during a space flight in Earth orbits. A rotation of the construction is considered. This motion can provide an optimal temperature distribution in the construction that is required for the polymerization reaction. The cylindrical construction of 80 m length with two hemispherical ends of 10 m radius is considered. The wall of the construction of 10 mm carbon fibers/epoxy matrix composite is irradiated by heat flux from the sun and radiates heat from the external surface by the Stefan- Boltzmann law. A stage of polymerization reaction is calculated as a function of temperature/time based on the laboratory experiments with certified composite materials for space exploitation. The curing kinetics of the composite is calculated for different inclination Low Earth Orbits (300 km altitude) and Geostationary Earth Orbit (40000 km altitude). The results show that • the curing process depends strongly on the Earth orbit and the rotation of the construction; • the optimal flight orbit and rotation can be found to provide the thermal regime that is sufficient for the complete curing of the considered construction. The study is supported by RFBR grant No.12-08-00970-a. 1. Briskman V., A.Kondyurin, K.Kostarev, V.Leontyev, M.Levkovich, A.Mashinsky, G.Nechitailo, T.Yudina, Polymerization in microgravity as a new process in space technology, Paper No IAA-97-IAA.12.1.07, 48th International Astronautical Congress, October 6-10, 1997, Turin Italy. 2. Kondyurin A.V., Building the shells of large space stations by the polymerisation of epoxy composites in open space, Int. Polymer Sci. and Technol., v.25, N4

User's manual for the Heat Pipe Space Radiator design and analysis Code (HEPSPARC)

Science.gov (United States)

Hainley, Donald C.

1991-01-01

A heat pipe space radiatior code (HEPSPARC), was written for the NASA Lewis Research Center and is used for the design and analysis of a radiator that is constructed from a pumped fluid loop that transfers heat to the evaporative section of heat pipes. This manual is designed to familiarize the user with this new code and to serve as a reference for its use. This manual documents the completed work and is intended to be the first step towards verification of the HEPSPARC code. Details are furnished to provide a description of all the requirements and variables used in the design and analysis of a combined pumped loop/heat pipe radiator system. A description of the subroutines used in the program is furnished for those interested in understanding its detailed workings.

Heat Transfer and Fluid Dynamics Measurements in the Expansion Space of a Stirling Cycle Engine

Science.gov (United States)

Jiang, Nan; Simon, Terrence W.

2006-01-01

The heater (or acceptor) of a Stirling engine, where most of the thermal energy is accepted into the engine by heat transfer, is the hottest part of the engine. Almost as hot is the adjacent expansion space of the engine. In the expansion space, the flow is oscillatory, impinging on a two-dimensional concavely-curved surface. Knowing the heat transfer on the inside surface of the engine head is critical to the engine design for efficiency and reliability. However, the flow in this region is not well understood and support is required to develop the CFD codes needed to design modern Stirling engines of high efficiency and power output. The present project is to experimentally investigate the flow and heat transfer in the heater head region. Flow fields and heat transfer coefficients are measured to characterize the oscillatory flow as well as to supply experimental validation for the CFD Stirling engine design codes. Presented also is a discussion of how these results might be used for heater head and acceptor region design calculations.

Main physical environmental drivers of occupant behaviour with regard to space heating energy demand

DEFF Research Database (Denmark)

Fabi, Valentina; Andersen, Rune Korsholm; Corgnati, Stefano Paolo

2012-01-01

Several studies have highlighted the significant gap between the predicted energy performance of buildings and their measured actual performance. Uncertainties regarding behaviour of building occupants are one of the key factors limiting the ability of energy simulation tools to accurately predict...... real building energy requirements . The paper focuses on the particular topics of space heating energy demand related to the occupants habits of adjusting heating set-points. The parameters influencing the user interaction with the heating control system are analyzed in literature for residential......) environmental conditions and the occupants’ heating set-point preferences. The paper aims at providing a reliable basis for a more accurate description of control action models in performance simulation applications....

Heating of large format filters in sub-mm and fir space optics

Science.gov (United States)

Baccichet, N.; Savini, G.

2017-11-01

Most FIR and sub-mm space borne observatories use polymer-based quasi-optical elements like filters and lenses, due to their high transparency and low absorption in such wavelength ranges. Nevertheless, data from those missions have proven that thermal imbalances in the instrument (not caused by filters) can complicate the data analysis. Consequently, for future, higher precision instrumentation, further investigation is required on any thermal imbalances embedded in such polymer-based filters. Particularly, in this paper the heating of polymers when operating at cryogenic temperature in space will be studied. Such phenomenon is an important aspect of their functioning since the transient emission of unwanted thermal radiation may affect the scientific measurements. To assess this effect, a computer model was developed for polypropylene based filters and PTFE-based coatings. Specifically, a theoretical model of their thermal properties was created and used into a multi-physics simulation that accounts for conductive and radiative heating effects of large optical elements, the geometry of which was suggested by the large format array instruments designed for future space missions. It was found that in the simulated conditions, the filters temperature was characterized by a time-dependent behaviour, modulated by a small scale fluctuation. Moreover, it was noticed that thermalization was reached only when a low power input was present.

Frosting characteristics and heating performance of a direct-expansion solar-assisted heat pump for space heating under frosting conditions

International Nuclear Information System (INIS)

Huang, Wenzhu; Ji, Jie; Xu, Ning; Li, Guiqiang

2016-01-01

Highlights: • Frosting and heating performance of DX-SAHP under frosting conditions is investigated. • The conditions when DX-SAHP frosts are studied. • The frosting process is observed during 360 min of operating. • The effect of ambient temperature, relative humidity and solar irradiation is analyzed. - Abstract: Direct expansion solar-assisted heat pump system (DX-SAHP) is promising in energy saving applications, but the performance of DX-SAHP under frosting conditions is rarely reported in the published literatures. In this paper, a DX-SAHP system with bare solar collectors for space heating is designed and experimentally investigated in the enthalpy difference lab with a solar simulator. The system is tested under a range of frosting conditions, with the ambient temperatures from 7 °C to −3 °C, the relative humidities of 50%, 70% and 90% and the solar irradiances of 0 W/m"2, 100 W/m"2, 200 W/m"2 and 300 W/m"2. The conditions when the DX-SAHP system frosts are studied. Results show that solar irradiance as low as 100 W/m"2 can totally prevent frosting when the ambient temperature is above −3 °C and the relative humidity is 70%. Besides, the frosting process is observed to be slower than that of fin-and-tube heat exchangers. The evaporator is not seriously frosted and the system performance is not significantly influenced after 360 min of continuous operating. Moreover the effects of ambient parameters, including the ambient temperature and the relative humidity, especially solar irradiation, on the system performance are studied and analyzed. Solar irradiation can effectively prevent or retard frosting, and also improve the heating performance of the DX-SAHP system. The DX-SAHP system is proved to be applicable under frosting conditions.

The potential reduction of household space heating CO2 emissions in the Netherlands

NARCIS (Netherlands)

Engelmoer, Wiebe

2011-01-01

SUMMARY Space heating is responsible for more than half of the total Dutch household energy demand, a large share is based on natural gas. With increasing concern about global warming and depleting gas reserves, energy saving has become an important topi

Solar space and water heating system at Stanford University Central Food Services Building. Final report

Energy Technology Data Exchange (ETDEWEB)

1980-05-01

This active hydronic domestic hot water and space heating system was 840 ft/sup 2/ of single-glazed, liquid, flat plate collectors and 1550 gal heat storage tanks. The following are discussed: energy conservation, design philosophy, operation, acceptance testing, performance data, collector selection, bidding, costs, economics, problems, and recommendations. An operation and maintenance manual and as-built drawings are included in appendices. (MHR)

Field measurement and estimate of gaseous and particle pollutant emissions from cooking and space heating processes in rural households, northern China

Science.gov (United States)

Chen, Yuanchen; Shen, Guofeng; Liu, Weijian; Du, Wei; Su, Shu; Duan, Yonghong; Lin, Nan; Zhuo, Shaojie; Wang, Xilong; Xing, Baoshan; Tao, Shu

2016-01-01

Pollutant emissions into outdoor air from cooking and space heating processes with various solid fuels were measured, and daily household emissions were estimated from the kitchen performance tests. The burning of honeycomb briquette had the lowest emission factors, while the use of wood produced the highest pollutants. Daily emissions from space heating were significantly higher than those from cooking, and the use of honeycomb briquette for cooking and raw coal chunk for space heating reduces 28%, 24% and 25% for CO, PM10 and PM2.5, compared to wood for cooking and peat for space heating. Much higher emissions were observed during the initial phase than the stable phase due to insufficient air supply and lower combustion temperature at the beginning of burning processes. However, more mass percent of fine particles formed in the later high temperature stable burning phase may increase potential inhalation exposure risks.

Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

International Nuclear Information System (INIS)

Pucker, Johanna; Zwart, Robin; Jungmeier, Gerfried

2012-01-01

In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO 2 -eq.) – carbon dioxide, methane and nitrous oxide – and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O 2 -blown entrained flow, O 2 -blown circulating fluidised bed and air–steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air–steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO 2 -eq. 32 kg MWh −1 of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O 2 -blown entrained flow and O 2 -blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO 2 -eq. 41 to 75 kg MWh −1 of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO 2 -eq. 57–75 kg MWh −1 of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59–2.13 MWh MWh −1 of heat output) than for the reference systems (in 1.37–1.51 MWh MWh −1 of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by 92% when air�

Combined Space and Water Heating: Next Steps to Improved Performance

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

2016-07-13

A combined space- and water-heating (combi) system uses a high-efficiency direct-vent burner that eliminates safety issues associated with natural draft appliances. Past research with these systems shows that using condensing water heaters or boilers with hydronic air handling units can provide both space and water heating with efficiencies of 90% or higher. Improved controls have the potential to reduce complexity and improve upon the measured performance. This project demonstrates that controls can significantly benefit these first-generation systems. Laboratory tests and daily load/performance models showed that the set point temperature reset control produced a 2.1%–4.3% (20–40 therms/year) savings for storage and hybrid water heater combi systems operated in moderate-load homes. The full modulation control showed additional savings over set point control (in high-load homes almost doubling the savings: 4%–5% over the no-control case). At the time of installation the reset control can be implemented for $200–$400, which would provide paybacks of 6–25 years for low-load houses and 3–15 years for high-load houses. Full modulation implementation costs would be similar to the outdoor reset and would provide paybacks of 5-½–20 years for low-load houses and 2-½–10 years for high-load houses.

Effect of Ducted HPWH on Space-Conditioning and Water Heating Energy Use -- Central Florida Lab Home

Energy Technology Data Exchange (ETDEWEB)

Colon, Carlos [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Martin, Eric [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Parker, Danny [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

2016-11-01

The purpose of this research is to investigate the impact of ducted heat pump water heaters (HPWHs) on space conditioning and water heating energy use in residential applications. Two identical HPWHs, each of 60 gallon capacity were tested side by side at the Flexible Residential Test facility (FRTF) laboratories of the Florida Solar Energy Center (FSEC) campus in Cocoa, Florida. The water heating experiments were run in each test house from July 2014 until February 2015.

Dry heat tolerance of the dry colony in Nostoc sp. HK-01 for useful usage in space agriculture

Science.gov (United States)

Kimura, Shunta; Tomita-Yokotani, Kaori; Yamashita, Masamichi; Sato, Seigo; Katoh, Hiroshi

Space agriculture producing foods is important as one of approach for space habitation. Nostoc sp. HK-01 is one of terrestrial cyanobacterium having a high dry tolerance and it has several ability, photosynthesis, nitrogen fixation and usefulness as a food, it is thought that it can be used for space agriculture. Besides, a study on each tolerance predicted at the time of introduction to space agriculture is necessary. Therefore, as one of the tolerance that are intended to space environment, dry heat ( 100(°) C, 10 h ) tolerance of dry colony in Nostoc sp. HK-01 has been investigated, but the detail function of them has not yet been elucidated. We focused on the extracellular polysaccharides ( EPS ) having the various tolerance, desiccation, low temperature, NaCl, and heavy particle beam. We will consider the function and useful usage of this cyanobacterum in space agriculture after the consideration of the results of contribution of the possibility that EPS improves dry heat tolerance under a dry condition.

Assessment of CFD Hypersonic Turbulent Heating Rates for Space Shuttle Orbiter

Science.gov (United States)

Wood, William A.; Oliver, A. Brandon

2011-01-01

Turbulent CFD codes are assessed for the prediction of convective heat transfer rates at turbulent, hypersonic conditions. Algebraic turbulence models are used within the DPLR and LAURA CFD codes. The benchmark heat transfer rates are derived from thermocouple measurements of the Space Shuttle orbiter Discovery windward tiles during the STS-119 and STS-128 entries. The thermocouples were located underneath the reaction-cured glass coating on the thermal protection tiles. Boundary layer transition flight experiments conducted during both of those entries promoted turbulent flow at unusually high Mach numbers, with the present analysis considering Mach 10{15. Similar prior comparisons of CFD predictions directly to the flight temperature measurements were unsatisfactory, showing diverging trends between prediction and measurement for Mach numbers greater than 11. In the prior work, surface temperatures and convective heat transfer rates had been assumed to be in radiative equilibrium. The present work employs a one-dimensional time-accurate conduction analysis to relate measured temperatures to surface heat transfer rates, removing heat soak lag from the flight data, in order to better assess the predictive accuracy of the numerical models. The turbulent CFD shows good agreement for turbulent fuselage flow up to Mach 13. But on the wing in the wake of the boundary layer trip, the inclusion of tile conduction effects does not explain the prior observed discrepancy in trends between simulation and experiment; the flight heat transfer measurements are roughly constant over Mach 11-15, versus an increasing trend with Mach number from the CFD.

Reducing residential solid fuel combustion through electrified space heating leads to substantial air quality, health and climate benefits in China's Beijing-Tianjin-Hebei region

Science.gov (United States)

Yang, J.; Mauzerall, D. L.

2017-12-01

During periods of high pollution in winter, household space heating can contribute more than half of PM2.5 concentrations in China's Beijing-Tianjin-Hebei (BTH) region. The majority of rural households and some urban households in the region still heat with small stoves and solid fuels such as raw coal, coal briquettes and biomass. Thus, reducing emissions from residential space heating has become a top priority of the Chinese government's air pollution mitigation plan. Electrified space heating is a promising alternative to solid fuel. However, there is little analysis of the air quality and climate implications of choosing various electrified heating devices and utilizing different electricity sources. Here we conduct an integrated assessment of the air quality, human health and climate implications of various electrified heating scenarios in the BTH region using the Weather Research and Forecasting model with Chemistry. We use the Multi-resolution Emission Inventory for China for the year 2012 as our base case and design two electrification scenarios in which either direct resistance heaters or air source heat pumps are installed to replace all household heating stoves. We initially assume all electrified heating devices use electricity from supercritical coal-fired power plants. We find that installing air source heat pumps reduces CO2 emissions and premature deaths due to PM2.5 pollution more than resistance heaters, relative to the base case. The increased health and climate benefits of heat pumps occur because they have a higher heat conversion efficiency and thus require less electricity for space heating than resistance heaters. We also find that with the same heat pump installation, a hybrid electricity source (40% of the electricity generated from renewable sources and the rest from coal) further reduces both CO2 emissions and premature deaths than using electricity only from coal. Our study demonstrates the air pollution and CO2 mitigation potential and

Renewable Heating And Cooling

Science.gov (United States)

Renewable heating and cooling is a set of alternative resources and technologies that can be used in place of conventional heating and cooling technologies for common applications such as water heating, space heating, space cooling and process heat.

Adaptive neuro-fuzzy based inferential sensor model for estimating the average air temperature in space heating systems

Energy Technology Data Exchange (ETDEWEB)

Jassar, S.; Zhao, L. [Department of Electrical and Computer Engineering, Ryerson University, 350 Victoria Street, Toronto, ON (Canada); Liao, Z. [Department of Architectural Science, Ryerson University (Canada)

2009-08-15

The heating systems are conventionally controlled by open-loop control systems because of the absence of practical methods for estimating average air temperature in the built environment. An inferential sensor model, based on adaptive neuro-fuzzy inference system modeling, for estimating the average air temperature in multi-zone space heating systems is developed. This modeling technique has the advantage of expert knowledge of fuzzy inference systems (FISs) and learning capability of artificial neural networks (ANNs). A hybrid learning algorithm, which combines the least-square method and the back-propagation algorithm, is used to identify the parameters of the network. This paper describes an adaptive network based inferential sensor that can be used to design closed-loop control for space heating systems. The research aims to improve the overall performance of heating systems, in terms of energy efficiency and thermal comfort. The average air temperature results estimated by using the developed model are strongly in agreement with the experimental results. (author)

Effect of Ducted HPWH on Space-Conditioning and Water Heating Energy Use -- Central Florida Lab Home

Energy Technology Data Exchange (ETDEWEB)

Colon, Carlos [Florida Solar Energy Center, Cocoa, FL (United States); Martin, Eric [Florida Solar Energy Center, Cocoa, FL (United States); Parker, Danny [Florida Solar Energy Center, Cocoa, FL (United States)

2016-11-01

The purpose of this research is to investigate the impact of ducted heat pump water heaters (HPWH's) on space conditioning and water heating energy use in residential applications. Two identical HPWH's, each of 60 gallon capacity were tested side by side at the Flexible Residential Test facility (FRTF) laboratories of the Florida Solar Energy Center (FSEC) campus in Cocoa, Florida. The water heating experiments were run in each test house from July 2014 until February 2015.

Heating of a fully saturated darcian half-space: Pressure generation, fluid expulsion, and phase change

Science.gov (United States)

Delaney, P.

1984-01-01

Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space. ?? 1984.

A study of upwind schemes on the laminar hypersonic heating predictions for the reusable space vehicle

Science.gov (United States)

Qu, Feng; Sun, Di; Zuo, Guang

2018-06-01

With the rapid development of the Computational Fluid Dynamics (CFD), Accurate computing hypersonic heating is in a high demand for the design of the new generation reusable space vehicle to conduct deep space exploration. In the past years, most researchers try to solve this problem by concentrating on the choice of the upwind schemes or the definition of the cell Reynolds number. However, the cell Reynolds number dependencies and limiter dependencies of the upwind schemes, which are of great importance to their performances in hypersonic heating computations, are concerned by few people. In this paper, we conduct a systematic study on these properties respectively. Results in our test cases show that SLAU (Simple Low-dissipation AUSM-family) is with a much higher level of accuracy and robustness in hypersonic heating predictions. Also, it performs much better in terms of the limiter dependency and the cell Reynolds number dependency.

Lunar Heat Flux Measurements Enabled by a Microwave Radiometer Aboard the Deep Space Gateway

Science.gov (United States)

Siegler, M.; Ruf, C.; Putzig, N.; Morgan, G.; Hayne, P.; Paige, D.; Nagihara, S.; Weber, R.

2018-02-01

We would like to present a concept to use the Deep Space Gateway as a platform for constraining the geothermal heat production, surface, and near-surface rocks, and dielectric properties of the Moon from orbit with passive microwave radiometery.

Heat exchanger optimization of a closed Brayton cycle for nuclear space propulsion

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Guilherme B.; Guimaraes, Lamartine N.F.; Braz Filho, Francisco A., E-mail: gbribeiro@ieav.cta.br, E-mail: guimarae@ieav.cta.br, E-mail: braz@ieav.cta.br [Instituto de Estudos Avancados (IEAV), Sao Jose dos Campos, SP (Brazil). Divisao de Energia Nuclear

2015-07-01

Nuclear power systems turned to space electric propulsion differs strongly from usual ground-based power systems regarding the importance of overall size and weight. For propulsion power systems, weight and efficiency are essential drivers that should be managed during conception phase. Considering that, this paper aims the development of a thermal model of a closed Brayton cycle that applies the thermal conductance of heat exchangers in order to predict the energy conversion performance. The centrifugal-flow turbine and compressor characterization were achieved using algebraic equations from literature data. The binary mixture of He-Xe with molecular weight of 40 g/mole is applied and the impact of heat exchanger optimization in thermodynamic irreversibilities is evaluated in this paper. (author)

Heat exchanger optimization of a closed Brayton cycle for nuclear space propulsion

International Nuclear Information System (INIS)

Ribeiro, Guilherme B.; Guimaraes, Lamartine N.F.; Braz Filho, Francisco A.

2015-01-01

Nuclear power systems turned to space electric propulsion differs strongly from usual ground-based power systems regarding the importance of overall size and weight. For propulsion power systems, weight and efficiency are essential drivers that should be managed during conception phase. Considering that, this paper aims the development of a thermal model of a closed Brayton cycle that applies the thermal conductance of heat exchangers in order to predict the energy conversion performance. The centrifugal-flow turbine and compressor characterization were achieved using algebraic equations from literature data. The binary mixture of He-Xe with molecular weight of 40 g/mole is applied and the impact of heat exchanger optimization in thermodynamic irreversibilities is evaluated in this paper. (author)

Miniature Heat Pipes

Science.gov (United States)

1997-01-01

Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-05-15

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

Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads

OpenAIRE

Monika Chmielowiec-Jablczyk; Andreas Schubert; Christian Kraft; Hubert Schwarze; Michal Wodtke; Michal Wasilczuk

2018-01-01

A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the ...

Regulation and Measurement of the Heat Generated by Automatic Tooth Preparation in a Confined Space.

Science.gov (United States)

Yuan, Fusong; Zheng, Jianqiao; Sun, Yuchun; Wang, Yong; Lyu, Peijun

2017-06-01

The aim of this study was to assess and regulate heat generation in the dental pulp cavity and circumambient temperature around a tooth during laser ablation with a femtosecond laser in a confined space. The automatic tooth preparing technique is one of the traditional oral clinical technology innovations. In this technique, a robot controlled an ultrashort pulse laser to automatically complete the three-dimensional teeth preparing in a confined space. The temperature control is the main measure for protecting the tooth nerve. Ten tooth specimens were irradiated with a femtosecond laser controlled by a robot in a confined space to generate 10 teeth preparation. During the process, four thermocouple sensors were used to record the pulp cavity and circumambient environment temperatures with or without air cooling. A statistical analysis of the temperatures was performed between the conditions with and without air cooling (p heat generated in the pulp cavity was lower than the threshold for dental pulp damage. These results indicate that femtosecond laser ablation with air cooling might be an appropriate method for automatic tooth preparing.

Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

Energy Technology Data Exchange (ETDEWEB)

Pucker, J.; Jungmeier, G. [JOANNEUM RESEARCH Forschungsgesellschaft mbH, RESOURCES - Institute for Water, Energy and Sustainability, Steyrergasse 17, 8010 Graz (Austria); Zwart, R. [Energy Research Centre of The Netherlands (ECN), Westerduinweg 3, 1755 LE Petten (Netherlands)

2012-03-15

In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO{sub 2}-eq.) - carbon dioxide, methane and nitrous oxide - and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O{sub 2}-blown entrained flow, O{sub 2}-blown circulating fluidised bed and air-steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air-steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO{sub 2}-eq. 32 kg MWh{sup -1} of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O{sub 2}-blown entrained flow and O{sub 2}-blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO{sub 2}-eq. 41 to 75 kg MWh{sup -1} of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO2-eq. 57-75 kg MWh{sup -1} of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59-2.13 MWh MWh{sup -1} of heat output) than for the reference systems (in 1.37-1.51 MWh MWh{sup -1} of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by

Reducing cell-to-cell spacing for large-format lithium ion battery modules with aluminum or PCM heat sinks under failure conditions

International Nuclear Information System (INIS)

Coleman, Brittany; Ostanek, Jason; Heinzel, John

2016-01-01

Highlights: • Finite element analysis to evaluate heat sinks for large format li-ion batteries. • Solid metal heat sink and composite heat sink (metal filler and wax). • Transient simulations show response from rest to steady-state with normal load. • Transient simulations of two different failure modes were considered. • Significance of spacing, material properties, interface quality, and phase change. - Abstract: Thermal management is critical for large-scale, shipboard energy storage systems utilizing lithium-ion batteries. In recent years, there has been growing research in thermal management of lithium-ion battery modules. However, there is little information available on the minimum cell-to-cell spacing limits for indirect, liquid cooled modules when considering heat release during a single cell failure. For this purpose, a generic four-cell module was modeled using finite element analysis to determine the sensitivity of module temperatures to cell spacing. Additionally, the effects of different heat sink materials and interface qualities were investigated. Two materials were considered, a solid aluminum block and a metal/wax composite block. Simulations were run for three different transient load profiles. The first profile simulates sustained high rate operation where the system begins at rest and generates heat continuously until it reaches steady state. And, two failure mode simulations were conducted to investigate block performance during a slow and a fast exothermic reaction, respectively. Results indicate that composite materials can perform well under normal operation and provide some protection against single cell failure; although, for very compact designs, the amount of wax available to absorb heat is reduced and the effectiveness of the phase change material is diminished. The aluminum block design performed well under all conditions, and showed that heat generated during a failure is quickly dissipated to the coolant, even under the

Characterization of dynamic thermal control schemes and heat transfer pathways for incorporating variable emissivity electrochromic materials into a space suit heat rejection system

Science.gov (United States)

Massina, Christopher James

The feasibility of conducting long duration human spaceflight missions is largely dependent on the provision of consumables such as oxygen, water, and food. In addition to meeting crew metabolic needs, water sublimation has long served as the primary heat rejection mechanism in space suits during extravehicular activity (EVA). During a single eight hour EVA, approximately 3.6 kg (8 lbm) of water is lost from the current suit. Reducing the amount of expended water during EVA is a long standing goal of space suit life support systems designers; but to date, no alternate thermal control mechanism has demonstrated the ability to completely eliminate the loss. One proposed concept is to convert the majority of a space suit's surface area into a radiator such that the local environment can be used as a radiative thermal sink for rejecting heat without mass loss. Due to natural variations in both internal (metabolic) loads and external (environmental) sink temperatures, radiative transport must be actively modulated in order to maintain an acceptable thermal balance. Here, variable emissivity electrochromic devices are examined as the primary mechanism for enabling variable heat rejection. This dissertation focuses on theoretical and empirical evaluations performed to determine the feasibility of using a full suit, variable emissivity radiator architecture for space suit thermal control. Operational envelopes are described that show where a given environment and/or metabolic load combination may or may not be supported by the evaluated thermal architecture. Key integration considerations and guidelines include determining allowable thermal environments, defining skin-to-radiator heat transfer properties, and evaluating required electrochromic performance properties. Analysis also considered the impacts of dynamic environmental changes and the architecture's extensibility to EVA on the Martian surface. At the conclusion of this work, the full suit, variable emissivity

Effects of Heating on Teflon(Registered Trademark) FEP Thermal Control Material from the Hubble Space Telescope

Science.gov (United States)

deGroh, Kim; Gaier, James R.; Hall, Rachelle L.; Norris, Mary Jo; Espe, Matthew P.; Cato, Daveen R.

1999-01-01

Metallized Teflon(Registered Trademark) FEP (fluorinated ethylene propylene) thermal control material on the Hubble Space Telescope (HST) is degrading in the space environment. Teflon(Registered Trademark) FEP thermal control blankets (space-facing FEP) retrieved during the first servicing mission (SM1) were found to be embrittled on solar facing surfaces and contained microscopic cracks. During the second servicing mission (SM2) astronauts noticed that the FEP outer layer of the multi-layer insulation (MLI) covering the telescope was cracked in many locations around the telescope. Large cracks were observed on the light shield, forward shell and equipment bays. A tightly curled piece of cracked FEP from the light shield was retrieved during SM2 and was severely embrittled, as witnessed by ground testing. A Failure Review Board (FRB) was organized to determine the mechanism causing the MLI degradation. Density, x-ray crystallinity and solid state nuclear magnetic resonance (NMR) analyses of FEP retrieved during SM1 were inconsistent with results of FEP retrieved during SM2. Because the retrieved SM2 material curled while in space, it experienced a higher temperature extreme during thermal cycling, estimated at 200 C, than the SM1 material, estimated at 50 C. An investigation on the effects of heating pristine and FEP exposed on HST was therefore conducted. Samples of pristine. SM1, and SM2 FEP were heated to 200 C and evaluated for changes in density and morphology. Elevated temperature exposure was found to have a major impact on the density of the retrieved materials. Characterization of polymer morphology of as-received and heated FEP samples by NMR provided results that were consistent with the density results. These findings have provided insight to the damage mechanisms of FEP in the space environment.

Development and preliminary assessment of the wall condensation heat transfer models for the SPACE code

International Nuclear Information System (INIS)

Park, Hyun Sik; Choi, Ki Yong; Moon, Sang Ki; Kim, Jung Woo; Kim, Kyung Doo

2009-01-01

The wall condensation heat transfer models are developed for the SPACE code and are assessed for various condensation conditions. Both default and alternative models were selected through an extensive literature survey. For a pure steam condensation, a maximum value among the Nusselt, Chato, and Shah's correlations is used in order to consider the geometric and turbulent effects. In the presence of non-condensable gases, the Colburn-Hougen's diffusion model was used as a default model and a non-iterative condensation model proposed by No and Park was selected as an alternative model. The wall condensation heat transfer models were assessed preliminarily by using arbitrary test conditions. Both wall condensation models could simulate the heat transfer coefficients and heat fluxes in the vertical, horizontal and turbulent conditions quite reasonably for a pure steam condensation. Both the default and alternative wall condensation models were also verified for the condensation heat transfer coefficient and heat flux in the presence of noncondensable gas. However, some improvements and further detailed verification are necessary for the condensation phenomena in the presence of noncondensable gas

A study on experiment and numerical simulation of heat exchanger in heating furnace

Directory of Open Access Journals (Sweden)

Z. C. Lv

2018-01-01

Full Text Available In this paper, air preheater is used the research object and its heat transfer law is studied by experiment and numerical simulation. The experimental data showed that with the increases of inlet air velocity, the comprehensive heat transfer coefficient and heat transfer efficiency increase, but the temperature efficiency decreases and the resistance loss on the air side increases. The numerical simulation results showed that the larger the diameter of the tube, the better the heat transfer effect. When horizontal spacing in the range of 290 - 305 mm and longitudinal spacing is 70 - 90 mm, the heat transfer effect is best. The optimized heat exchanger structure is that diameter is 60 mm, horizontal spacing is 300 mm, longitudinal spacing is 90 mm. As the inlet air flow rate increases, the heat transfer efficiency increases, but the temperature efficiency decreases and the resistance loss on the air side increases.

Thermal energy storage for electricity-driven space heating in a day-ahead electricity market

DEFF Research Database (Denmark)

Pensini, Alessandro

2012-01-01

Thermal Energy Storage (TES) in a space heating (SH) application was investigated. The study aimed to determine the economic benefits of introducing TES into an electricity-driven SH system under a day-ahead electricity market. The performance of the TES was assessed by comparing the cost...... of electricity in a system with a TES unit to the case where no storage is in use and the entire heat requirement is fulfilled by purchasing electricity according to the actual load. The study had two goals: 1. Determining how the size – in terms of electricity input (Pmax) and energy capacity (Emax...

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...

Feasibility of geothermal space/water heating for Mammoth Lakes Village, California. Final report, September 1976--September 1977

Energy Technology Data Exchange (ETDEWEB)

Sims, A.V.; Racine, W.C.

1977-12-01

Results of a study to determine the technical, economic, and environmental feasibility of geothermal district heating for Mammoth Lakes Village, California are reported. The geothermal district heating system selected is technically feasible and will use existing technology in its design and operation. District heating can provide space and water heating energy for typical customers at lower cost than alternative sources of energy. If the district heating system is investor owned, lower costs are realized after five to six years of operation, and if owned by a nonprofit organization, after zero to three years. District heating offers lower costs than alternatives much sooner in time if co-generation and/or DOE participation in system construction are included in the analysis. During a preliminary environmental assessment, no potential adverse environmental impacts could be identified of sufficient consequence to preclude the construction and operation of the proposed district heating system. A follow-on program aimed at implementing district heating in Mammoth is outlined.

Quantitative Analysis of the Principal-Agent Problem in Commercial Buildings in the U.S.: Focus on Central Space Heating and Cooling

Energy Technology Data Exchange (ETDEWEB)

Blum, Helcio; Sathaye, Jayant

2010-05-14

We investigate the existence of the principal-agent (PA) problem in non-government, non-mall commercial buildings in the U.S. in 2003. The analysis concentrates on space heating and cooling energy consumed by centrally installed equipment in order to verify whether a market failure caused by the PA problem might have prevented the installation of energy-efficient devices in non-owner-occupied buildings (efficiency problem) and/or the efficient operation of space-conditioning equipment in these buildings (usage problem). Commercial Buildings Energy Consumption Survey (CBECS) 2003 data for single-owner, single-tenant and multi-tenant occupied buildings were used for conducting this evaluation. These are the building subsets with the appropriate conditions for assessing both the efficiency and the usage problems. Together, these three building types represent 51.9percent of the total floor space of all buildings with space heating and 59.4percent of the total end-use energy consumption of such buildings; similarly, for space cooling, they represent 52.7percent of floor space and 51.6percent of energy consumption. Our statistical analysis shows that there is a usage PA problem. In space heating it applies only to buildings with a small floor area (<_50,000 sq. ft.). We estimate that in 2003 it accounts for additional site energy consumption of 12.3 (+ 10.5 ) TBtu (primary energy consumption of 14.6 [+- 12.4] TBtu), corresponding to 24.0percent (+- 20.5percent) of space heating and 10.2percent (+- 8.7percent) of total site energy consumed in those buildings. In space cooling, however, the analysis shows that the PA market failure affects the complete set of studied buildings. We estimate that it accounts for a higher site energy consumption of 8.3 (+-4.0) TBtu (primary energy consumption of 25.5 [+- 12.2]TBtu), which corresponds to 26.5percent (+- 12.7percent) of space cooling and 2.7percent (+- 1.3percent) of total site energy consumed in those buildings.

Natural convective flows in a horizontal channel provided with heating isothermal blocks: Effect of the inter blocks spacing

International Nuclear Information System (INIS)

Bakkas, M.; Hasnaoui, M.; Amahmid, A.

2010-01-01

A numerical study of laminar steady natural convection induced in a two dimensional horizontal channel provided with rectangular heating blocks, periodically mounted on its lower wall, is carried out. The blocks' surface temperature, T H ' , is maintained constant and the former are connected with adiabatic surfaces. The upper wall of the channel is maintained cold at a temperature T C ' H ' . Fluid flow, temperature fields and heat transfer rates are presented for different combinations of the governing parameters which are the Rayleigh number (10 2 ≤Ra≤2x10 6 ), the blocks' spacing (1/4≤C=l ' /H ' ≤1), the blocks' height (1/8≤B=h ' /H ' ≤1/2) and the relative width of the blocks (A=(L ' -l ' )/H ' =1/2). The results obtained in the case of air (Pr = 0.72) show that the flow structure and the heat transfer are significantly influenced by the control parameters. It is found that there are situations where the increase of the blocks' spacing leads to a reduction of heat transfer.

Flow and heat transfer in parallel channel attached with equally-spaced ribs, 2

International Nuclear Information System (INIS)

Kunugi, Tomoaki; Takizuka, Takakazu

1980-09-01

Using a computer code for the analysis of the flow and heat transfer in a parallel channel attached with equally-spaced ribs, calculations are performed when a pitch to rib-width ratio is 7 : 1, a rib-width to rib-height ratio is 2 : 1 and a channel-height to rib-height is 3 : 1. Assuming that the fluid properties and the heat-flux at the wall of this channel are constant, characteristics of the flow and heat transfer are analyzed in the range of Reynolds number from 10 to 250. The following results are obtained: (1) The separation region behind a rib grows downstream with the increase of Reynolds number. (2) The pressure drop of ribbed channel is greater than that of the smooth channel, and increases as Reynolds number increases. (3) The mean Nusselt number of ribbed channel is about 10 - 11 at the upper wall and about 7.5 at the lower wall in the range of Reynolds number from 10 to 250. (author)

Experimental determination of convective heat transfer coefficients in the separated flow region of the Space Shuttle Solid Rocket Motor

Science.gov (United States)

Whitesides, R. Harold; Majumdar, Alok K.; Jenkins, Susan L.; Bacchus, David L.

1990-01-01

A series of cold flow heat transfer tests was conducted with a 7.5-percent scale model of the Space Shuttle Rocket Motor (SRM) to measure the heat transfer coefficients in the separated flow region around the nose of the submerged nozzle. Modifications were made to an existing 7.5 percent scale model of the internal geometry of the aft end of the SRM, including the gimballed nozzle in order to accomplish the measurements. The model nozzle nose was fitted with a stainless steel shell with numerous thermocouples welded to the backside of the thin wall. A transient 'thin skin' experimental technique was used to measure the local heat transfer coefficients. The effects of Reynolds number, nozzle gimbal angle, and model location were correlated with a Stanton number versus Reynolds number correlation which may be used to determine the convective heating rates for the full scale Space Shuttle Solid Rocket Motor nozzle.

Marangoni convection radiative flow of dusty nanoliquid with exponential space dependent heat source

Directory of Open Access Journals (Sweden)

Basavarajappa Mahanthesh

2017-12-01

Full Text Available The flow of liquids submerged with nanoparticles is of significance to industrial applications, specifically in nuclear reactors and the cooling of nuclear systems to improve energy efficiency. The application of nanofluids in water-cooled nuclear systems can result in a significant improvement of their economic performance and/or safety margins. Therefore, in this paper, Marangoni thermal convective boundary layer dusty nanoliquid flow across a flat surface in the presence of solar radiation is studied. A two phase dusty liquid model is considered. Unlike classical temperature-dependent heat source effects, an exponential space-dependent heat source aspect is considered. Stretching variables are utilized to transform the prevailing partial differential system into a nonlinear ordinary differential system, which is then solved numerically via the Runge-Kutta-Fehlberg approach coupled with a shooting technique. The roles of physical parameters are focused in momentum and heat transport distributions. Graphical illustrations are also used to consider local and average Nusselt numbers. We examined the results under both linear and quadratic variation of the surface temperature. Our simulations established that the impact of Marangoni flow is useful for an enhancement of the heat transfer rate.

Pulsating Heat Pipes, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — An advanced heat transport technology is presented that can enable space nuclear power systems to transfer reactor heat, convert heat into electricity, reject waste...

Heat and mass transfer across gas-filled enclosed spaces between a hot liquid surface and a cooled roof

Energy Technology Data Exchange (ETDEWEB)

Ralph, J C; Bennett, A W [Atomic Energy Research Establishment, Harwell, Oxfordshire (United Kingdom)

1977-01-01

A detailed knowledge is required of the amounts of sodium vapour which may be transported from the hot surface of a fast reactor coolant pool through the cover gas to cooler regions of the structure. Evaporation from the unbounded liquid surfaces of lakes and seas has been studied extensively but the heat and mass transfer mechanisms in gas-vapour mixtures which occur in enclosed spaces have received less attention. Recent work at Harwell has provided a theoretical model from which the heat and mass transfer in idealised plane cavities can be calculated. An experimental study is reported in this paper which seeks to verify the theoretical prediction. Heat and mass transfer measurements have been made on a system in which a heated water pool transfers heat and mass across a gas-filled space to a cooled horizontal cover plate. Several cover gases were used in the experiments and the results show that, provided the partial density of the vapour is low compared with that of the gas, the heat transfer mechanism is that of combined convection and radiation. The enhancement in heat transfer due to the presence of the vapour is broadly consistent with assumption of a direct analogy between heat and mass transfer neglecting condensation in the interspace. The mass transfer measurements, in which water condensing on the cooled roof was measured directly, showed for low roof temperatures an imbalance between the mass and heat transfer. This observation is consistent with the theoretical predictions that heat transfer in the convecting system should be independent of the amount of condensation and 'rain-back' within the cavity. The results of tests with helium showed that convection was entirely suppressed by the presence of the water vapour. This confirms the behaviour predicted for gas-vapour mixtures in which the vapour density is of the same order as the gas density. (author)

Heat-pipe transient model for space applications

International Nuclear Information System (INIS)

Tournier, J.; El-Genk, M.S.; Juhasz, A.J.

1991-01-01

A two-dimensional model is developed for simulating heat pipes transient performance following changes in the input/rejection power or in the evaporator/condenser temperatures. The model employs the complete form of governing equations and momentum and energy jump conditions at the liquid-vapor interface. Although the model is capable of handling both cylindrical and rectangular geometries, the results reported are for a circular heat pipe with liquid lithium as the working fluid. The model incorporates a variety of other working fluids, such as water, ammonia, potassium, sodium, and mercury, and offers combinations of isothermal, isoflux, convective and radiative heating/cooling conditions in the evaporator and condenser regions of the heat pipe. Results presented are for lithium heat pipes with exponential heating of the evaporator and isothermal cooling of the condenser

Profiling Space Heating Behavior in Chilean Social Housing: Towards Personalization of Energy Efficiency Measures

Directory of Open Access Journals (Sweden)

Victor Bunster

2015-06-01

Full Text Available Global increases in the demand for energy are imposing strong pressures over the environment while compromising the capacity of emerging economies to achieve sustainable development. In this context, implementation of effective strategies to reduce consumption in residential buildings has become a priority concern for policy makers as minor changes at the household scale can result in major energy savings. This study aims to contribute to ongoing research on energy consumer profiling by exploring the forecasting capabilities of discrete socio-economic factors that are accessible through social housing allocation systems. Accordingly, survey data gathered by the Chilean Ministry of Social Development was used identify key characteristics that may predict firewood usage for space heating purposes among potential beneficiaries of the Chilean social housing program. The analyzed data evidences strong correlations between general household characteristics and space heating behavior in certain climatic zones, suggesting that personalized delivery of energy efficiency measures can potentially increase the effectiveness of initiatives aimed towards the reduction of current patterns of consumption.

Heat pipe nuclear reactor for space power

Science.gov (United States)

Koening, D. R.

1976-01-01

A heat-pipe-cooled nuclear reactor has been designed to provide 3.2 MWth to an out-of-core thermionic conversion system. The reactor is a fast reactor designed to operate at a nominal heat-pipe temperature of 1675 K. Each reactor fuel element consists of a hexagonal molybdenum block which is bonded along its axis to one end of a molybdenum/lithium-vapor heat pipe. The block is perforated with an array of longitudinal holes which are loaded with UO2 pellets. The heat pipe transfers heat directly to a string of six thermionic converters which are bonded along the other end of the heat pipe. An assembly of 90 such fuel elements forms a hexagonal core. The core is surrounded by a thermal radiation shield, a thin thermal neutron absorber, and a BeO reflector containing boron-loaded control drums.

Direct Heat

Energy Technology Data Exchange (ETDEWEB)

Lienau, P J

1990-01-01

Potential resources and applications of earth heat in the form of geothermal energy are large. United States direct uses amount to 2,100 MWt thermal and worldwide 8,850 MWt above a reference temperature of 35 degrees Celsius. Space and district heating are the major direct uses of geothermal energy. Equipment employed in direct use projects is of standard manufacture and includes downhole and circulation pumps, transmission and distribution pipelines, heat exchangers and convectors, heat pumps and chillers. Direct uses of earth heat discussed are space and district heating, greenhouse heating and fish farming, process and industrial applications. The economic feasibility of direct use projects is governed by site specific factors such as location of user and resource, resource quality, system load factor and load density, as well as financing. Examples are presented of district heating in Klamath Falls, and Elko. Further developments of direct uses of geothermal energy will depend on matching user needs to the resource, and improving load factors and load density.

Space chamber experiments of ohmic heating by high power microwave from the solar power satellite

Energy Technology Data Exchange (ETDEWEB)

Kaya, N.; Matsumoto, H.

1981-12-01

It is quantitatively predicted that a high power microwave from the Solar Power Satellite (SPS) nonlinearly interacts with the ionospheric plasma. The possible nonlinear interactions are ohmic heating, self-focusing and parametric instabilities. A rocket experiment called MINIX (Microwave-Ionosphere Nonlinear Interaction Experiment) has been attempted to examine these effects, but is note reported here. In parallel to the rocket experiment, a laboratory experiment in a space plasma simulation chamber has been carried out in order to examine ohmic heating in detail and to develop a system of the rocket experiment. Interesting results were observed and these results were utilized to revise the system of the rocket experiments. A significant microwave heating of plasma up to 150% temperature increase was observed with little electron density decrease. It was shown that the temperature increase is not due to the RF breakdown but to the ohmic heating in the simulated ionospheric plasma. These microwave effects have to be taken into account in the SPS Project in the future.

Evaluation and demonstration of decentralized space and water heating versus centralized services for new and rehabilitated multifamily buildings. Final report

Energy Technology Data Exchange (ETDEWEB)

Belkus, P. [Foster-Miller, Inc., Waltham, MA (US); Tuluca, A. [Steven Winter Associates, Inc., Norwalk, CT (US)

1993-06-01

The general objective of this research was aimed at developing sufficient technical and economic know-how to convince the building and design communities of the appropriateness and energy advantages of decentralized space and water heating for multifamily buildings. Two main goals were established to guide this research. First, the research sought to determine the cost-benefit advantages of decentralized space and water heating versus centralized systems for multifamily applications based on innovative gas piping and appliance technologies. The second goal was to ensure that this information is made available to the design community.

Solar Energy Gain and Space-Heating Energy Supply Analyses for Solid-Wall Dwelling Retrofitted with the Experimentally Achievable U-value of Novel Triple Vacuum Glazing

Directory of Open Access Journals (Sweden)

Saim Memon

2017-06-01

Full Text Available A considerable effort is devoted to devising retrofit solutions for reducing space-heating energy in the domestic sector. Existing UK solid-wall dwellings, which have both heritage values and historic fabric, are being improved but they tend to have meagre thermal performance, partly, due to the heat-loss through glazings. This paper takes comparative analyses approach to envisage space-heating supply required in order to maintain thermal comfort temperatures and attainable solar energy gains to households with the retrofit of an experimentally achievable thermal performance of the fabricated sample of triple vacuum glazing to a UK solid-wall dwelling. 3D dynamic thermal models (timely regimes of heating, occupancy, ventilation and internal heat gains of an externally-insulated solid-wall detached dwelling with a range of existing glazing types along with triple vacuum glazings are modelled. A dramatic decrease of space-heating load and moderate increase of solar gains are resulted with the dwelling of newly achievable triple vacuum glazings (having centre-of-pane U-value of 0.33 Wm-2K-1 compared to conventional glazing types. The space-heating annual cost of single glazed dwellings was minimised to 15.31% (≈USD 90.7 with the retrofit of triple-vacuum glazings. An influence of total heat-loss through the fabric of solid-wall dwelling was analysed with steady-state calculations which indicates a fall of 10.23 % with triple vacuum glazings compared to single glazings.

Experimental Space Shuttle Orbiter Studies to Acquire Data for Code and Flight Heating Model Validation

Science.gov (United States)

Wadhams, T. P.; Holden, M. S.; MacLean, M. G.; Campbell, Charles

2010-01-01

In an experimental study to obtain detailed heating data over the Space Shuttle Orbiter, CUBRC has completed an extensive matrix of experiments using three distinct models and two unique hypervelocity wind tunnel facilities. This detailed data will be employed to assess heating augmentation due to boundary layer transition on the Orbiter wing leading edge and wind side acreage with comparisons to computational methods and flight data obtained during the Orbiter Entry Boundary Layer Flight Experiment and HYTHIRM during STS-119 reentry. These comparisons will facilitate critical updates to be made to the engineering tools employed to make assessments about natural and tripped boundary layer transition during Orbiter reentry. To achieve the goals of this study data was obtained over a range of Mach numbers from 10 to 18, with flight scaled Reynolds numbers and model attitudes representing key points on the Orbiter reentry trajectory. The first of these studies were performed as an integral part of Return to Flight activities following the accident that occurred during the reentry of the Space Shuttle Columbia (STS-107) in February of 2003. This accident was caused by debris, which originated from the foam covering the external tank bipod fitting ramps, striking and damaging critical wing leading edge heating tiles that reside in the Orbiter bow shock/wing interaction region. During investigation of the accident aeroheating team members discovered that only a limited amount of experimental wing leading edge data existed in this critical peak heating area and a need arose to acquire a detailed dataset of heating in this region. This new dataset was acquired in three phases consisting of a risk mitigation phase employing a 1.8% scale Orbiter model with special temperature sensitive paint covering the wing leading edge, a 0.9% scale Orbiter model with high resolution thin-film instrumentation in the span direction, and the primary 1.8% scale Orbiter model with detailed

Ablative overlays for Space Shuttle leading edge ascent heat protection

Science.gov (United States)

Strauss, E. L.

1975-01-01

Ablative overlays were evaluated via a plasma-arc simulation of the ascent pulse on the leading edge of the Space Shuttle Orbiter. Overlay concepts included corkboard, polyisocyanurate foam, low-density Teflon, epoxy, and subliming salts. Their densities ranged from 4.9 to 81 lb per cu ft, and the thicknesses varied from 0.107 to 0.330 in. Swept-leading-edge models were fabricated from 30-lb per cu ft silicone-based ablators. The overlays were bonded to maintain the surface temperature of the base ablator below 500 F during ascent. Foams provided minimum-weight overlays, and subliming salts provided minimum-thickness overlays. Teflon left the most uniform surface after ascent heating.

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 2, technologies 1: Reactors, heat transport, integration issues

Science.gov (United States)

Wetch, J. R.

1988-01-01

The objectives of the Megawatt Class Nuclear Space Power System (MCNSPS) study are summarized and candidate systems and subsystems are described. Particular emphasis is given to the heat rejection system and the space reactor subsystem.

Heat transfer on HLM cooled wire-spaced fuel pin bundle simulator in the NACIE-UP facility

Energy Technology Data Exchange (ETDEWEB)

Di Piazza, Ivan, E-mail: ivan.dipiazza@enea.it [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone, Camugnano (Italy); Angelucci, Morena; Marinari, Ranieri [University of Pisa, Dipartimento di Ingegneria Civile e Industriale, Pisa (Italy); Tarantino, Mariano [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone, Camugnano (Italy); Forgione, Nicola [University of Pisa, Dipartimento di Ingegneria Civile e Industriale, Pisa (Italy)

2016-04-15

Highlights: • Experiments with a wire-wrapped 19-pin fuel bundle cooled by LBE. • Wall and bulk temperature measurements at three axial positions. • Heat transfer and error analysis in the range of low mass flow rates and Péclet number. • Comparison of local and section-averaged Nusselt number with correlations. - Abstract: The NACIE-UP experimental facility at the ENEA Brasimone Research Centre (Italy) allowed to evaluate the heat transfer coefficient of a wire-spaced fuel bundle cooled by lead-bismuth eutectic (LBE). Lead or lead-bismuth eutectic are very attractive as coolants for the GEN-IV fast reactors due to the good thermo-physical properties and the capability to fulfil the GEN-IV goals. Nevertheless, few experimental data on heat transfer with heavy liquid metals (HLM) are available in literature. Furthermore, just a few data can be identified on the specific topic of wire-spaced fuel bundle cooled by HLM. Additional analysis on thermo-fluid dynamic behaviour of the HLM inside the subchannels of a rod bundle is necessary to support the design and safety assessment of GEN. IV/ADS reactors. In this context, a wire-spaced 19-pin fuel bundle was installed inside the NACIE-UP facility. The pin bundle is equipped with 67 thermocouples to monitor temperatures and analyse the heat transfer behaviour in different sub-channels and axial positions. The experimental campaign was part of the SEARCH FP7 EU project to support the development of the MYRRHA irradiation facility (SCK-CEN). Natural and mixed circulation flow regimes were investigated, with subchannel Reynolds number in the range Re = 1000–10,000 and heat flux in the range q″ = 50–500 kW/m{sup 2}. Local Nusselt numbers were calculated for five sub-channels in different ranks at three axial positions. Section-averaged Nusselt number was also defined and calculated. Local Nusselt data showed good consistency with some of the correlation existing in literature for heat transfer in liquid metals

Heat transfer on HLM cooled wire-spaced fuel pin bundle simulator in the NACIE-UP facility

International Nuclear Information System (INIS)

Di Piazza, Ivan; Angelucci, Morena; Marinari, Ranieri; Tarantino, Mariano; Forgione, Nicola

2016-01-01

Highlights: • Experiments with a wire-wrapped 19-pin fuel bundle cooled by LBE. • Wall and bulk temperature measurements at three axial positions. • Heat transfer and error analysis in the range of low mass flow rates and Péclet number. • Comparison of local and section-averaged Nusselt number with correlations. - Abstract: The NACIE-UP experimental facility at the ENEA Brasimone Research Centre (Italy) allowed to evaluate the heat transfer coefficient of a wire-spaced fuel bundle cooled by lead-bismuth eutectic (LBE). Lead or lead-bismuth eutectic are very attractive as coolants for the GEN-IV fast reactors due to the good thermo-physical properties and the capability to fulfil the GEN-IV goals. Nevertheless, few experimental data on heat transfer with heavy liquid metals (HLM) are available in literature. Furthermore, just a few data can be identified on the specific topic of wire-spaced fuel bundle cooled by HLM. Additional analysis on thermo-fluid dynamic behaviour of the HLM inside the subchannels of a rod bundle is necessary to support the design and safety assessment of GEN. IV/ADS reactors. In this context, a wire-spaced 19-pin fuel bundle was installed inside the NACIE-UP facility. The pin bundle is equipped with 67 thermocouples to monitor temperatures and analyse the heat transfer behaviour in different sub-channels and axial positions. The experimental campaign was part of the SEARCH FP7 EU project to support the development of the MYRRHA irradiation facility (SCK-CEN). Natural and mixed circulation flow regimes were investigated, with subchannel Reynolds number in the range Re = 1000–10,000 and heat flux in the range q″ = 50–500 kW/m"2. Local Nusselt numbers were calculated for five sub-channels in different ranks at three axial positions. Section-averaged Nusselt number was also defined and calculated. Local Nusselt data showed good consistency with some of the correlation existing in literature for heat transfer in liquid metals for

Gas-operated heat pump for monovalent space heating and tap water heating. A seizable contribution to carbon dioxide emission control; Gasbetriebene Waermepumpe zur monovalenten Raumbeheizung und Trinkwassererwaermung. Ein greifbarer Beitrag zur Reduktion der CO{sub 2}-Emissionen

Energy Technology Data Exchange (ETDEWEB)

Heikrodt, K.; Heckt, R. [Viessmann Werke GmbH und Co., Allendorf (Germany)

1999-07-01

The project had the objectives to develop a Vuilleumier heat pump for space heating and make an experimental study testing it as a heat generator for a heating system for one- and multi-family houses. Apart from monovalent operation, the following boundary conditions were defined: provision for connection to existing heating systems, even radiator heatings with 75 C/60 C, tap water heating, and air-source heat. Performance constant, manufacturing cost, freedom from maintenance, and service life were taken into consideration in the design, rating and construction of the unit. (orig.) [German] Ziel des Vorhabens war die Entwicklung einer Vuilleumier-Waermepumpe zur Raumbeheizung und deren experimentelle Untersuchung als Waermeerzeuger fuer ein Heizungssystem in Ein- und Mehrfamilienhaeusern. Als Rahmebedingungen wurden neben einer monovalenten Betriebsweise auch die moegliche Anbindung an bestehende Heizungssysteme, sogar Radiatorheizungen mit 75 C/60 C, Trinkwassererwaermung und Luft als Waermequelle festgelegt. Leistungszahl, Herstellkosten, Wartungsfreiheit und Lebensdauer wurden in Konzeption, Auslegung und Konstruktion beruecksichtigt. (orig.)

Estimating end-use emissions factors for policy analysis: the case of space cooling and heating.

Science.gov (United States)

Jacobsen, Grant D

2014-06-17

This paper provides the first estimates of end-use specific emissions factors, which are estimates of the amount of a pollutant that is emitted when a unit of electricity is generated to meet demand from a specific end-use. In particular, this paper provides estimates of emissions factors for space cooling and heating, which are two of the most significant end-uses. The analysis is based on a novel two-stage regression framework that estimates emissions factors that are specific to cooling or heating by exploiting variation in cooling and heating demand induced by weather variation. Heating is associated with similar or greater CO2 emissions factor than cooling in all regions. The difference is greatest in the Midwest and Northeast, where the estimated CO2 emissions factor for heating is more than 20% larger than the emissions factor for cooling. The minor differences in emissions factors in other regions, combined with the substantial difference in the demand pattern for cooling and heating, suggests that the use of overall regional emissions factors is reasonable for policy evaluations in certain locations. Accurately quantifying the emissions factors associated with different end-uses across regions will aid in designing improved energy and environmental policies.

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

Directory of Open Access Journals (Sweden)

K. I. Denisova

2016-01-01

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

Future heat supply of our cities. Heating by waste heat

Energy Technology Data Exchange (ETDEWEB)

Brachetti, H E [Stadtwerke Hannover A.G. (Germany, F.R.); Technische Univ. Hannover (Germany, F.R.))

1976-08-01

The energy-price crisis resulted in structural changes of the complete energy supply and reactivated the question of energy management with respect to the optimum solution of meeting the energy requirements for space heating. Condensation power plants are increasingly replaced by thermal stations, the waste heat of which is used as so-called district heat. Thermal power stations must be situated close to urban areas. The problem of emission of harmful materials can partly be overcome by high-level emission. The main subject of the article, however, is the problem of conducting and distributing the heat. The building costs of heat pipeline systems and the requirements to be met by heat pipelines such as strength, heat insulation and protection against humidity and ground water are investigated.

Numerical simulations and analyses of temperature control loop heat pipe for space CCD camera

Science.gov (United States)

Meng, Qingliang; Yang, Tao; Li, Chunlin

2016-10-01

As one of the key units of space CCD camera, the temperature range and stability of CCD components affect the image's indexes. Reasonable thermal design and robust thermal control devices are needed. One kind of temperature control loop heat pipe (TCLHP) is designed, which highly meets the thermal control requirements of CCD components. In order to study the dynamic behaviors of heat and mass transfer of TCLHP, particularly in the orbital flight case, a transient numerical model is developed by using the well-established empirical correlations for flow models within three dimensional thermal modeling. The temperature control principle and details of mathematical model are presented. The model is used to study operating state, flow and heat characteristics based upon the analyses of variations of temperature, pressure and quality under different operating modes and external heat flux variations. The results indicate that TCLHP can satisfy the thermal control requirements of CCD components well, and always ensure good temperature stability and uniformity. By comparison between flight data and simulated results, it is found that the model is to be accurate to within 1°C. The model can be better used for predicting and understanding the transient performance of TCLHP.

Heat pump evaluation for Space Station ATCS evolution

Science.gov (United States)

Ames, Brian E.; Petete, Patricia A.

1991-01-01

A preliminary feasibility assessment of the application of a vapor compression heat pump to the Active Thermal Control System (ATCS) of SSF is presented. This paper focuses on the methodology of raising the surface temperature of the radiators for improved heat rejection. Some of the effects of the vapor compression cycle on SSF examined include heat pump integration into ATCS, constraints on the heat pump operating parameters, and heat pump performance enhancements.

Heat pipes to reduce engine exhaust emissions

Science.gov (United States)

Schultz, D. F. (Inventor)

1984-01-01

A fuel combustor is presented that consists of an elongated casing with an air inlet conduit portion at one end, and having an opposite exit end. An elongated heat pipe is mounted longitudinally in the casing and is offset from and extends alongside the combustion space. The heat pipe is in heat transmitting relationship with the air intake conduit for heating incoming air. A guide conduit structure is provided for conveying the heated air from the intake conduit into the combustion space. A fuel discharge nozzle is provided to inject fuel into the combustion space. A fuel conduit from a fuel supply source has a portion engaged in heat transfer relationship of the heat pipe for preheating the fuel. The downstream end of the heat pipe is in heat transfer relationship with the casing and is located adjacent to the downstream end of the combustion space. The offset position of the heat pipe relative to the combustion space minimizes the quenching effect of the heat pipe on the gaseous products of combustion, as well as reducing coking of the fuel on the heat pipe, thereby improving the efficiency of the combustor.

Improvements in or relating to heat exchangers

International Nuclear Information System (INIS)

Taylor, P.A.

1978-01-01

According to the present invention there is provided a method of producing superheated steam by use of the heat in liquid sodium, in which liquid sodium is caused to flow through a space having boundaries of which no part is common with the boundaries of a space in which vapour is produced, a fluid that is inert to sodium is heated by heat exchange at the boundaries of the space through which the liquid sodium flows and serves as the heating medium for the production of vapour, and the vapour is subsequently heated to the final degree of superheat by heat exchange with liquid sodium in a space that has a common boundary with a space through which liquid sodium is passed. (U.K.)

Solar air heating system for combined DHW and space heating

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S.; Bosanac, M.

2002-12-01

The project deals with the development and testing of a simple system for utilization of the summer excess heat from small solar air heating systems for preheating of fresh air. The principle of the system is to lead the heated air down around a domestic hot water tank letting the surface of the tank act as heat exchanger between the air and the water. In order to increase the heat transfer, coefficient fins into the air stream were mounted on the tank. A complete system with 3 m{sup 2} solar air collector, ductworks and a 85 litre storage were set up and extensively monitored. The air stream through the system was created by a fan connected directly to one or two PV-panels leading to a solar radiation dependent flow rate without the use of any other control. Based on monitoring results the system was characterized and a TRNSYS model of the system was developed and calibrated/validated. The monitoring and the simulations with the TRNSYS model revealed several interesting things about the system. The monitoring revealed that the system is capable of bringing the temperature of the water in the storage above 60 deg. C at warm days with clear sky conditions. The storage is very stratified, which is beneficial as usable hot water temperatures rather quickly are obtained. The performance was highly dependent on the airflow rate through the system. It can be concluded that the investigated system will have a performance in the order of 500 kWh during the winter, spring and autumn months and around 250 kWh during the four summer months - or in total a yearly performance of 750 kWh/m{sup 2}. A small traditional solar heating system for preheating of domestic hot water would have a higher performance during the four summer months, but no performance during the rest of the year if the system is installed in a summer house, which only is occupied during the summer. The parametric analysis further indicates that it is possible to further optimise the system when the thermal

Heat receivers for solar dynamic space power systems

Science.gov (United States)

Perez-Davis, Marla Esther

A review of state-of-the-art technology is presented and discussed for phase change materials. Some of the advanced solar dynamic designs developed as part of the Advanced Heat Receiver Conceptual Design Study performed for LeRC are discussed. The heat receivers are analyzed and several recommendations are proposed, including two new concepts. The first concept evaluated the effect of tube geometries inside the heat receiver. It was found that a triangular configuration would provide better heat transfer to the working fluid, although not necessarily with a reduction in receiver size. A sensible heat receiver considered in this study uses vapor grown graphite fiber-carbon (VGCF/C) composite as the thermal storage media and was designed for a 7 kW Brayton engine. The proposed heat receiver stores the required energy to power the system during eclipse in the VGCF/C composite. The heat receiver analysis was conducted through the Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA) software package. The proposed heat receiver compares well with other latent and advanced sensible heat receivers while avoiding the problems associated with latent heat storage salts and liquid metal heat pipes. The weight and size of the system can be optimized by changes in geometry and technology advances for this new material. In addition to the new concepts, the effect of atomic oxygen on several materials is reviewed. A test was conducted for atomic oxygen attack on boron nitride, which experienced a negligible mass loss when exposed to an atomic oxygen fluence of 5 x 10 exp 21 atoms/sq cm. This material could be used to substitute the graphite aperture plate of the heat receiver.

Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate.

Directory of Open Access Journals (Sweden)

Dustyn Roberts

Full Text Available A subject-specific model of instantaneous cost of transport (ICOT is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters-mass, height, (estimated maximum oxygen uptake, and (estimated maximum joint torques-are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90 inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326-0.348 of the experimental total COT (0.311-0.358 across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic energy pathway similar to that of steady-state walking.

Heat pipes and use of heat pipes in furnace exhaust

Science.gov (United States)

Polcyn, Adam D.

2010-12-28

An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

Thermal Performance of Solar Air Heater Having Absorber Plate with V-Down Discrete Rib Roughness for Space-Heating Applications

Directory of Open Access Journals (Sweden)

Rajendra Karwa

2013-01-01

Full Text Available The paper presents results of thermal performance analysis of a solar air heater with v-down discrete rib roughness on the air flow side of the absorber plate, which supplies heated air for space heating applications. The air heater operates in a closed loop mode with inlet air at a fixed temperature of 295 K from the conditional space. The ambient temperature varied from 278 K to 288 K corresponding to the winter season of Western Rajasthan, India. The results of the analysis are presented in the form of performance plots, which can be utilized by a designer for calculating desired air flow rate at different ambient temperature and solar insolation values.

Solar-assisted heat pump system for cost-effective space heating and cooling

Energy Technology Data Exchange (ETDEWEB)

Andrews, J W; Kush, E A; Metz, P D

1978-03-01

The use of heat pumps for the utilization of solar energy is studied. Two requirements for a cost-effective system are identified: (1) a special heat pump whose coefficient of performance continues to rise with source temperature over the entire range appropriate for solar assist, and (2) a low-cost collection and storage subsystem able to supply solar energy to the heat pump efficiently at low temperatures. Programs leading to the development of these components are discussed. A solar assisted heat pump system using these components is simulated via a computer, and the results of the simulation are used as the basis for a cost comparison of the proposed system with other solar and conventional systems.

Investigation of the thermal resistance of timber attic spaces with reflective foil and bulk insulation, heat flow up

Energy Technology Data Exchange (ETDEWEB)

Belusko, M.; Bruno, F.; Saman, W. [Institute for Sustainable Systems and Technologies, University of South Australia, Mawson Lakes Boulevard, SA 5095 (Australia)

2011-01-15

An experimental investigation was undertaken in which the thermal resistance for the heat flow through a typical timber framed pitched roofing system was measured under outdoor conditions for heat flow up. The measured thermal resistance of low resistance systems such as an uninsulated attic space and a reflective attic space compared well with published data. However, with higher thermal resistance systems containing bulk insulation within the timber frame, the measured result for a typical installation was as low as 50% of the thermal resistance determined considering two dimensional thermal bridging using the parallel path method. This result was attributed to three dimensional heat flow and insulation installation defects, resulting from the design and construction method used. Translating these results to a typical house with a 200 m{sup 2} floor area, the overall thermal resistance of the roof was at least 23% lower than the overall calculated thermal resistance including two dimensional thermal bridging. When a continuous layer of bulk insulation was applied to the roofing system, the measured values were in agreement with calculated resistances representing a more reliable solution. (author)

Anthropogenic Heat Flux Estimation from Space: Results of the second phase of the URBANFLUXES Project

Science.gov (United States)

Chrysoulakis, Nektarios; Marconcini, Mattia; Gastellu-Etchegorry, Jean-Philippe; Grimmond, Sue; Feigenwinter, Christian; Lindberg, Fredrik; Del Frate, Fabio; Klostermann, Judith; Mitraka, Zina; Esch, Thomas; Landier, Lucas; Gabey, Andy; Parlow, Eberhard; Olofson, Frans

2017-04-01

The H2020-Space project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of Copernicus Sentinels to retrieve anthropogenic heat flux, as a key component of the Urban Energy Budget (UEB). URBANFLUXES advances the current knowledge of the impacts of UEB fluxes on urban heat island and consequently on energy consumption in cities. In URBANFLUXES, the anthropogenic heat flux is estimated as a residual of UEB. Therefore, the rest UEB components, namely, the net all-wave radiation, the net change in heat storage and the turbulent sensible and latent heat fluxes are independently estimated from Earth Observation (EO), whereas the advection term is included in the error of the anthropogenic heat flux estimation from the UEB closure. The Discrete Anisotropic Radiative Transfer (DART) model is employed to improve the estimation of the net all-wave radiation balance, whereas the Element Surface Temperature Method (ESTM), adjusted to satellite observations is used to improve the estimation the estimation of the net change in heat storage. Furthermore the estimation of the turbulent sensible and latent heat fluxes is based on the Aerodynamic Resistance Method (ARM). Based on these outcomes, QF is estimated by regressing the sum of the turbulent heat fluxes versus the available energy. In-situ flux measurements are used to evaluate URBANFLUXES outcomes, whereas uncertainties are specified and analyzed. URBANFLUXES is expected to prepare the ground for further innovative exploitation of EO in scientific activities (climate variability studies at local and regional scales) and future and emerging applications (sustainable urban planning, mitigation technologies) to benefit climate change mitigation/adaptation. This study presents the results of the second phase of the project and detailed information on URBANFLUXES is available at: http://urbanfluxes.eu

46 CFR 108.213 - Heating requirements.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Heating requirements. 108.213 Section 108.213 Shipping... EQUIPMENT Construction and Arrangement Accommodation Spaces § 108.213 Heating requirements. (a) Each accommodation space must be heated by a heating system that can maintain at least 20°C. (68°F.). (b) Radiators...

Simulation and optimization study on a solar space heating system combined with a low temperature ASHP for single family rural residential houses in Beijing

DEFF Research Database (Denmark)

Deng, Jie; Tian, Zhiyong; Fan, Jianhua

2016-01-01

A pilot project of the solar water heating system combined with a low temperature air source heat pump (ASHP) unit was established in 2014 in a detached residential house in the rural region of Beijing, in order to investigate the system application prospect for single family houses via system...... optimization design and economic analysis. The established system was comprised of the glass heat-pipe based evacuated tube solar collectors with a gross area of 18.8 m2 and an ASHP with a stated heating power of 8 kW for the space heating of a single family rural house of 81.4 m2. The dynamic thermal...... with good building insulation were undertaken to figure out the system economical efficiency in the rural regions of Beijing. The results show that the payback periods of the solar space heating system combined with the ASHP with the collector areas 15.04-22.56 m2 are 17.3-22.4 years for the established...

Heat pipes in modern heat exchangers

International Nuclear Information System (INIS)

Vasiliev, Leonard L.

2005-01-01

Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 10 3 -10 5 W/m 2 K, heat pipe thermal resistance is 0.01-0.03 K/W, therefore leading to smaller area and mass of heat exchangers. Miniature and micro heat pipes are welcomed for electronic components cooling and space two-phase thermal control systems. Loop heat pipes, pulsating heat pipes and sorption heat pipes are the novelty for modern heat exchangers. Heat pipe air preheaters are used in thermal power plants to preheat the secondary-primary air required for combustion of fuel in the boiler using the energy available in exhaust gases. Heat pipe solar collectors are promising for domestic use. This paper reviews mainly heat pipe developments in the Former Soviet Union Countries. Some new results obtained in USA and Europe are also included

General-purpose heat source project and space nuclear safety and fuels program. Progress report

International Nuclear Information System (INIS)

Maraman, W.J.

1979-12-01

This formal monthly report covers the studies related to the use of 238 PuO 2 in radioisotopic power systems carried out for the Advanced Nuclear Systems and Projects Division of the Los Alamos Scientific Laboratory. The two programs involved are general-purpose heat source development and space nuclear safety and fuels. Most of the studies discussed hear are of a continuing nature. Results and conclusions described may change as the work continues

Combined Active and Passive Solar Space Heating and Solar Hot Water Systems for an Elementary School in Boise, Idaho.

Science.gov (United States)

Smull, Neil A.; Armstrong, Gerald L.

1979-01-01

Amity Elementary School in Boise, Idaho, features a solar space heating and domestic hot water system along with an earth covering to accommodate the passive aspects of energy conservation. (Author/MLF)

Generation of Domestic Hot Water, Space Heating and Driving Pattern Profiles for Integration Analysis of Active Loads in Low Voltage Grids

DEFF Research Database (Denmark)

Diaz de Cerio Mendaza, Iker; Pigazo, Alberto; Bak-Jensen, Birgitte

2013-01-01

at household level. Despite of the well-known flexible service that this kind of loads can provide, their flexibility is highly dependent of the domestic hot water and space heating demand and the driving habits of each user. This paper presents two methodologies employed to randomly generate thermal power......The changes in the Danish energy sector, consequence of political agreements, are expected to have direct impact in the actual power distribution systems. Large number of electric boiler, heat pumps and electric vehicles are planned and will cope large percentage of the future power consumption...... demand and electric vehicle driving profiles, to be used for power grid calculations. The generated thermal profiles relied on a statistical analysis made from real domestic hot water and space heating data from 25 households of a typical Danish residential area. The driving profiles instead were formed...

In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

Science.gov (United States)

Pohner, John A.; Dempsey, Brian P.; Herold, Leroy M.

1990-01-01

Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger.

The impact of consumer behavior on residential energy demand for space heating

Energy Technology Data Exchange (ETDEWEB)

Haas, R.; Auer, H.; Biermayr, P. [Vienna Univ. of Technology (Austria). Inst. of Energy Economics

1998-04-01

Besides technical parameters, consumer behavior is the most important issue with respect to energy consumption in households. In this paper, the results of a cross-section analysis of Austrian households are presented. The impact of the following parameters on residential energy demand for space heating have been investigated: (i) thermal quality of buildings; (ii) consumer behavior; (iii) heating degree days; (iv) building type (single- or multi-family dwellings). The result of this investigation provides evidence of a rebound-effect of about 15 to 30% due to building retrofit. This leads to the conclusion that energy savings achieved in practice (and straightforward the reduction in CO{sub 2} emissions) due to energy conservation measures will be lower than those calculated in engineering conservation studies. Straightforward, the most important conclusions for energy policy makers are: (i) Standards, building codes, respectively, are important tools to increase the thermal quality of new buildings; and (ii) Due to prevailing low energy prices, a triggering tool has to be implemented which may be rebates or loans. (orig.)

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

Energy Efficiency and Sustainability Evaluation of Space and Water Heating in Urban Residential Buildings of the Hot Summer and Cold Winter Zone in China

OpenAIRE

Xiao Chen; Yongquan Wen; Nanyang Li

2016-01-01

With the urbanization process of the hot summer and cold winter (HSCW) zone in China, the energy consumption of space and water heating in urban residential buildings of the HSCW zone has increased rapidly. This study presents the energy efficiency and sustainability evaluation of various ways of space and water heating taking 10 typical cities in the HSCW zone as research cases. Two indicators, primary energy efficiency (PEE) and sustainability index based on exergy efficiency, are adopted t...

Heat exchanger

Science.gov (United States)

Daman, Ernest L.; McCallister, Robert A.

1979-01-01

A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.

Performance of Space Heating in a Modern Energy System

DEFF Research Database (Denmark)

Elmegaard, Brian

2011-01-01

In the paper we study the performance of a number of heat supply technologies. The background of the study is the changes in the Danish energy systems over the last three decades which have caused integration of large shares of combined heat and power (CHP), renewable fuels and wind power....... These changes mean that there is a significant integration of electricity and heat supply in the system and that several technologies may be beneficial. In particular, heat pumps are under consideration and are often considered to be renewable energy. We study how to distribute fuel and emissions to the heat...... supply. We find that heat supply is low-efficient seen from an exergy viewpoint, between 1% and 26% utilization. As exergy is a quantification of primary energy, we conclude that far better utilization of primary energy is possible. We also find that combined heat and power and domestic heat pumps...

Heat roadmap China

DEFF Research Database (Denmark)

Xiong, Weiming; Wang, Yu; Mathiesen, Brian Vad

2015-01-01

District heating is regarded as a key element of energy saving actions in the Chinese national energy strategy, while space heating in China is currently still dominated by coal boilers. However, there is no existing quantitative study to analyse the future heat strategy for China. Therefore...

Exergy analysis of a two-stage ground source heat pump with a vertical bore for residential space conditioning under simulated occupancy

International Nuclear Information System (INIS)

Ally, Moonis R.; Munk, Jeffrey D.; Baxter, Van D.; Gehl, Anthony C.

2015-01-01

Highlights: • Exergy and energy analysis of a vertical-bore ground source heat pump over a 12-month period is presented. • The ground provided more than 75% of the heating energy. • Performance metrics are presented. • Sources of systemic inefficiency are identified and prioritized using Exergy analysis. • Understanding performance metrics is vital for judicial use of renewable energy. - Abstract: This twelve-month field study analyzes the performance of a 7.56 W (2.16-ton) water-to-air-ground source heat pump (WA-GSHP) to satisfy domestic space conditioning loads in a 253 m 2 house in a mixed-humid climate in the United States. The practical feasibility of using the ground as a source of renewable energy is clearly demonstrated. Better than 75% of the energy needed for space heating was extracted from the ground. The average monthly electricity consumption for space conditioning was only 40 kW h at summer and winter thermostat set points of 24.4 °C and 21.7 °C, respectively. The WA-GSHP shared the same 94.5 m vertical bore ground loop with a separate water-to-water ground-source heat pump (WW-GSHP) for meeting domestic hot water needs in the same house. Sources of systemic irreversibility, the main cause of lost work, are identified using Exergy and energy analysis. Quantifying the sources of Exergy and energy losses is essential for further systemic improvements. The research findings suggest that the WA-GSHPs are a practical and viable technology to reduce primary energy consumption and greenhouse gas emissions under the IECC 2012 Standard, as well as the European Union (EU) 2020 targets of using renewable energy resources

Well posedness and regularity for heat equation with the initial condition in weighted Orlitz-Slobodetskii space subordinated to Orlicz space like lambda (log lambda0alpha and the logarithmic weight

Czech Academy of Sciences Publication Activity Database

Kałamajska, A.; Krbec, Miroslav

2015-01-01

Roč. 28, č. 3 (2015), s. 677-713 ISSN 1139-1138 R&D Projects: GA ČR GAP201/10/1920 Institutional research plan: CEZ:AV0Z1019905 Keywords : evolution problems * heat equation * Orlitz-Slobodetskii spaces * Orlitz-Sobolev spaces Subject RIV: BA - General Mathematics Impact factor: 0.631, year: 2015 http://link.springer.com/article/10.1007%2Fs13163-014-0164-4

Experimental validation of the buildings energy performance (PEC assessment methods with reference to occupied spaces heating

Directory of Open Access Journals (Sweden)

Cristian PETCU

2010-01-01

Full Text Available This paper is part of the series of pre-standardization research aimed to analyze the existing methods of calculating the Buildings Energy Performance (PEC in view of their correction of completing. The entire research activity aims to experimentally validate the PEC Calculation Algorithm as well as the comparative application, on the support of several case studies focused on representative buildings of the stock of buildings in Romania, of the PEC calculation methodology for buildings equipped with occupied spaces heating systems. The targets of the report are the experimental testing of the calculation models so far known (NP 048-2000, Mc 001-2006, SR EN 13790:2009, on the support provided by the CE INCERC Bucharest experimental building, together with the complex calculation algorithms specific to the dynamic modeling, for the evaluation of the occupied spaces heat demand in the cold season, specific to the traditional buildings and to modern buildings equipped with solar radiation passive systems, of the ventilated solar space type. The schedule of the measurements performed in the 2008-2009 cold season is presented as well as the primary processing of the measured data and the experimental validation of the heat demand monthly calculation methods, on the support of CE INCERC Bucharest. The calculation error per heating season (153 days of measurements between the measured heat demand and the calculated one was of 0.61%, an exceptional value confirming the phenomenological nature of the INCERC method, NP 048-2006. The mathematical model specific to the hourly thermal balance is recurrent – decisional with alternating paces. The experimental validation of the theoretical model is based on the measurements performed on the CE INCERC Bucharest building, within a time lag of 57 days (06.01-04.03.2009. The measurements performed on the CE INCERC Bucharest building confirm the accuracy of the hourly calculation model by comparison to the values

Utah State Prison Space Heating with Geothermal Heat Third Semi-Annual Report for the Period January 1981 - July 1981

Energy Technology Data Exchange (ETDEWEB)

None

1981-11-01

Facing certain cost overruns and lacking information about the long term productivity of the Crystal Hot Springs geothermal resource, costs of construction for the geothermal retrofit, and the method of disposal of geothermal waste water, the Energy Office embarked on a strategy that would enable the project participants to develop accurate cost information on the State Prison Space Heating Program through the completion of Task 5-Construction. The strategy called for: (1) Completion of the resource assessment to determine whether test well USP/TH-1 could be used as a production well. If well USP/TH-1 was found to have sufficient production capacity, money would not have to be expended on drilling another production well. (2) Evaluation of disposal alternatives and estimation of the cost of each alternative. There was no contingency in the original budget to provide for a reinjection disposal system. Cooperative agreement DE EC07-ET27027 indicated that if a disposal system requiring reinjection was selected for funding that task would be negotiated with DOE and the budget amended accordingly. (3) Completion of the preliminary engineering and design work. Included in this task was a thorough net present value cash flow analysis and an assessment of the technical feasibility of a system retrofit given the production characteristics of well USP/TH-1 . In addition, completion of the preliminary design would provide cost estimates for the construction and commissioning of the minimum security geothermal space heating system. With this information accurate costs for each task would be available, allowing the Energy Office to develop strategies to optimize the use of money in the existing budget to ensure completion of the program. Reported herein is a summary of the work towards the completion of these three objectives conducted during the period of January 1981 through June 1981.

NUMERICAL ANALYSIS OF HEAT STORAGE OF SOLAR HEAT IN FLOOR CONSTRUCTION

DEFF Research Database (Denmark)

Weitzmann, Peter; Holck, Ole; Svendsen, Svend

2003-01-01

with the highest energy con-sumption. The reduction depends on the solar collector area, distribution of the insulation thickness, heat-ing demand and control strategy, but not on pipe spacing and layer thickness and material. Finally, it is shown that the system can also be used for comfort heating of tiled...

Infrared astronomy seeing the heat : from William Herschel to the Herschel space observatory

CERN Document Server

Clements, David L

2014-01-01

Uncover the Secrets of the Universe Hidden at Wavelengths beyond Our Optical GazeWilliam Herschel's discovery of infrared light in 1800 led to the development of astronomy at wavelengths other than the optical. Infrared Astronomy - Seeing the Heat: from William Herschel to the Herschel Space Observatory explores the work in astronomy that relies on observations in the infrared. Author David L. Clements, a distinguished academic and science fiction writer, delves into how the universe works, from the planets in our own Solar System to the universe as a whole. The book first presents the major t

Geothermal space/water heating for Mammoth Lakes Village, California. Quarterly technical progress report, 13 December 1976-12 March 1977

Energy Technology Data Exchange (ETDEWEB)

Sims, A.V.; Racine, W.C.

1977-01-01

During the second three months of this feasibility study to determine the technical, economic and environmental feasibility of heating Mammoth Lakes Village, California using geothermal energy, the following work was accomplished. A saturation survey of the number and types of space and water heaters currently in use in the Village was completed. Electric energy and ambient temperature metering equipment was installed. Peak heating demand for Mammoth Lakes was estimated for the years 1985, 1990 and 2000. Buildings were selected which are considered typical of Mammoth Lakes in terms of their heating systems to be used in estimating the cost of installing hydronic heating systems in Mammoth. Block diagrams and an order of magnitude cost comparison were prepared for high-temperature and low-temperature geothermal district heating systems. Models depicting a geothermal district heating system and a geothermal-electric power plant were designed, built and delivered to ERDA in Washington. Local input to the feasibility study was obtained from representatives of the State of California Departments of Transportation and Fish and Game, US Forest Service, and Mono County Planning Department.

Evaluation of Technical and Utility Programmatic Challenges With Residential Forced-Air Integrated Space/Water Heat Systems

Energy Technology Data Exchange (ETDEWEB)

Kingston, Tim [Partnership for Advanced Residential Retrofit, Des Plaines, IL (United States); Vadnal, Hillary [Partnership for Advanced Residential Retrofit, Des Plaines, IL (United States); Scott, Shawn [Partnership for Advanced Residential Retrofit, Des Plaines, IL (United States); Kalensky, Dave [Partnership for Advanced Residential Retrofit, Des Plaines, IL (United States)

2016-12-01

This multi-unit field demonstration of combined space and water heating (combi) systems was conducted to help document combi system installation and performance issues that needed to be addressed through research. The objective of the project was to put commercialized forced-air tankless combi units into the field through local contractors that were trained by manufacturers and GTI staff under the auspices of utility-implemented ETPs.

Building America Case Study: Effect of Ducted HPWH on Space Conditioning and Water Heating Energy Use - Central Florida Lab Home, Cocoa, Florida

Energy Technology Data Exchange (ETDEWEB)

C. Colon, E. Martin, and D. Parker

2017-04-01

The purpose of this research is to investigate the impact of ducted heat pump water heaters (HPWH's) on space conditioning and water heating energy use in residential applications. Two identical HPWH's, each of 60 gallon capacity were tested side by side at the Flexible Residential Test facility (FRTF) laboratories of the Florida Solar Energy Center (FSEC) campus in Cocoa, Florida. The water heating experiments were run in each test house from July 2014 until February 2015.

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

Science.gov (United States)

Pei, Guihong; Zhang, Liyin

2016-01-01

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

Facility with a nuclear district heating reactor

International Nuclear Information System (INIS)

Straub, H.

1988-01-01

The district heating reactor has a pressure vessel which contains the reactor core and at least one coolant conducting primary heat carrier surrounded by a heat sink. The pressure vessel has two walls with a space between them. This space is connected with a container which contains air as heat isolating medium and water as heat conducting medium. During the normal reactor operation the space is filled by air from the container with the aid of a blower, whereas in the case of a break-down of the cooling system it is filled by water which flows out of the container by gravity after the blower has been switched off. The after-heat, generated in the reactor core during cooling break-down, is removed into the heat sink surrounding the pressure vessel in a safe and simple way. 6 figs

Industrial furnace with improved heat transfer

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, M.; Lingle, T.M.

1993-07-20

A method is described for effecting improved heat transfer with in an industrial furnace having a cylindrical furnace section, a door at one end of the furnace section, an end plate at the opposite end of the section a circular fan plate concentrically positioned within the furnace section to define a cylindrical fan chamber between the plate and the end section with a fan there between and a heat treat chamber between the plate and the door, the fan plate defining a non-orificing annular space extending between the interior of the cylindrical furnace section and the outer edge of the plate, the plate having a centrally located under-pressure opening extending there through and a plurality of circumferentially spaced tubular heating elements extending through the annular space into the heat treating chamber, the method comprising the steps of: (a) heating the heating elements to a temperature which is hotter that the temperature of the work within the heat treating chamber; (b) rotating the fan at a speed sufficient to form a portion of the furnace atmosphere as a wind mass swirling about the fan chamber; (c) propagating the wind mass through the annular space into the heat treating chamber as a swirling wind mass in the form of an annulus, the wind mass impinging the heating elements to establish heat transfer contact therewith while the mass retains its annulus shape until contacting the door and without any significant movement of the wind mass into the center of the heat treating chamber; (d) drawing the wind mass through the under-pressure zone after the wind mass comes into heat transfer contact with the work in the heat treating chamber; and (e) thereafter heating the work by radiation from the beating elements at high furnace temperatures in excess of about 1,600 F.

Feasibility of using the water from the abandoned and flooded coal mines as an energy resource for space heating

OpenAIRE

Athresh, AP

2017-01-01

This research project aims to study the feasibility of using the water from the abandoned and flooded coal mines for space heating applications using a Ground Source Heat Pump (GSHP) in open loop configuration and take a conceptual idea to a commercial deployment level. The flooded coal mines are the legacy that has been left behind after the three centuries of continuous operations by the coal mining industry. The closure of all coal mines in the UK has led to the flooding of all those aband...

Remote control systems for space heating. Product overview 2010 and recommendations - Final report; Fernsteuerungen fuer Raumheizungen. Produktuebersicht 2010 und Empfehlungen - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Geilinger, E.; Bush, E. [Bush Energie GmbH, Felsberg (Switzerland); Venzin, T. [Hochschule fuer Technik und Wirtschaft (HTW) Chur, Chur (Switzerland); Nipkow, J. [Arena, Zuerich (Switzerland)

2010-09-15

Saving space heating energy by remote control: A remote-controlled space heating system allows a person to lower the room temperature in homes that go unoccupied for periods of time to the lowest temperature that's safe to keep the pipes from freezing while they're away. Comfort is guaranteed because the desired room temperature or mode can be activated in time before the guests arrive, via text message, phone or the internet. As most people simply leave unoccupied homes heated, the remote-controlled system saves up to 70% of heating energy when used actively. Market overview and product features: This report presents remote control devices that are currently available on the market. Their advantages and disadvantages are discussed as well as their technical features and function. Most of them are universal remote controls that have various uses, including temperature control. The report also discusses requirements that not all the examined products meet. Some lack an emergency power supply, the possibility for manual control or the ability to check the current temperature of the home from a remote location. Better planning for remote control: The critical issue proved not to be the remote control device itself, but the heating systems. Unfortunately, they often don't provide an option to be extended by remote control. We therefore call on the manufacturers to equip all new heating systems with options for remote control. It would also be helpful and desirable to provide information on the internet or in the technical documentation on how to connect a remote control device and which products are suitable - both for existing and new heating systems. If the system cannot be retrofitted, it should be described whether and how a central remote control with room thermostat can be installed. Improving communication: In this study, remote control and heating suppliers were interviewed as well as planners, installers and users of remote-controlled heating. Their responses

Heat kernel analysis for Bessel operators on symmetric cones

DEFF Research Database (Denmark)

Möllers, Jan

2014-01-01

. The heat kernel is explicitly given in terms of a multivariable $I$-Bessel function on $Ω$. Its corresponding heat kernel transform defines a continuous linear operator between $L^p$-spaces. The unitary image of the $L^2$-space under the heat kernel transform is characterized as a weighted Bergmann space...

Heat pipe and method of production of a heat pipe

International Nuclear Information System (INIS)

Kemp, R.S.

1975-01-01

The heat pipe consists of a copper pipe in which a capillary network or wick of heat-conducting material is arranged in direct contact with the pipe along its whole length. Furthermore, the interior space of the tube contains an evaporable liquid for pipe transfer. If water is used, the capillary network consists of, e.g., a phosphorus band network. To avoid contamination of the interior of the heat pipe during sealing, its ends are closed by mechanical deformation so that an arched or plane surface is obtained which is in direct contact with the network. After evacuation of the interior space, the remaining opening is closed with a tapered pin. The ratio wall thickness/tube diameter is between 0.01 and 0.6. (TK/AK) [de

Thermal design heat sinks, thermoelectrics, heat pipes, compact heat exchangers, and solar cells

CERN Document Server

Lee, H S

2010-01-01

The proposed is written as a senior undergraduate or the first-year graduate textbook,covering modern thermal devices such as heat sinks, thermoelectric generators and coolers, heat pipes, and heat exchangers as design components in larger systems. These devices are becoming increasingly important and fundamental in thermal design across such diverse areas as microelectronic cooling, green or thermal energy conversion, and thermal control and management in space, etc. However, there is no textbook available covering this range of topics. The proposed book may be used as a capstone design cours

Development of a coal fired pulse combustor for residential space heating. Phase I, Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

1988-04-01

This report presents the results of the first phase of a program for the development of a coal-fired residential combustion system. This phase consisted of the design, fabrication, testing, and evaluation of an advanced pulse combustor sized for residential space heating requirements. The objective was to develop an advanced pulse coal combustor at the {approximately} 100,000 Btu/hr scale that can be integrated into a packaged space heating system for small residential applications. The strategy for the development effort included the scale down of the feasibility unit from 1-2 MMBtu/hr to 100,000 Btu/hr to establish a baseline for isolating the effect of scale-down and new chamber configurations separately. Initial focus at the residential scale was concentrated on methods of fuel injection and atomization in a bare metal unit. This was followed by incorporating changes to the advanced chamber designs and testing of refractory-lined units. Multi-fuel capability for firing oil or gas as a secondary fuel was also established. Upon completion of the configuration and component testing, an optimum configuration would be selected for integrated testing of the pulse combustor unit. The strategy also defined the use of Dry Ultrafine Coal (DUC) for Phases 1 and 2 of the development program with CWM firing to be a product improvement activity for a later phase of the program.

Passive heat removal from containment

International Nuclear Information System (INIS)

Gou, P.F.; Townsend, H.E.

1990-01-01

This patent describes a heat removal system for removing heat from a containment of a nuclear reactor. It comprises: a sealed suppression chamber in the containment; means for venting steam from the nuclear reactor into the suppression chamber upon occurrence of an event requiring dissipation of heat from the nuclear reactor. The suppression chamber containing a quantity of water; the suppression chamber having a gas-containing space above the water; a heat exchanger disposed within the gas-containing space of the suppression chamber; the heat exchanger including an enclosed structure for holding a heat-exchange fluid; means for metering a supply of heat-exchange fluid to the heat exchanger to maintain a predetermined level thereof in the enclosed structure. The heat-exchange fluid boiling in the heat exchanger in consequence of heat transfer thereto from steam present in the suppression chamber; means for separating a heat-exchange fluid vapor in the heat exchanger from the heat-exchange fluid; and means for discharging the vapor immediately following its separation from heat-exchange fluid directly from the heat exchanger to a location exterior of the containment, whereby heat is discharged from the suppression chamber, and the containment is maintained at a temperature and pressure below its design value

46 CFR 72.20-50 - Heating and cooling.

Science.gov (United States)

2010-10-01

... 46 Shipping 3 2010-10-01 2010-10-01 false Heating and cooling. 72.20-50 Section 72.20-50 Shipping... Accommodations for Officers and Crew § 72.20-50 Heating and cooling. (a) All manned spaces must be adequately heated and cooled in a manner suitable to the purpose of the space. (b) The heating and cooling system...

Utah State Prison Space Heating with Geothermal Heat Second Semi-Annual Report for the Period June 1980 - December 1980

Energy Technology Data Exchange (ETDEWEB)

None

1981-04-01

Reported herein is a summary of work conducted during the six monty period June, 1980 through December, 1980 of the project under contract to develop the Crystal Hot Springs geothermal resource to provide space and hot water heating for the minimum security building at the Utah State Prison. Efforts during this reporting period have been directed towards the resource assessment phase of the program. Specifically, progress includes: (1) completion of the gravity modeling efforts to define the subsurface structural configuration in the vicinity of the Crystal Hot Springs area, (2) selection of the most promising production targets for a test drilling program, (3) completion of the test drilling program, and (4) testing and monitoring of test well USP/TH-1.

Direct utilization of geothermal energy for space and water heating at Marlin, Texas. Final report

Energy Technology Data Exchange (ETDEWEB)

Conover, M.F.; Green, T.F.; Keeney, R.C.; Ellis, P.F. II; Davis, R.J.; Wallace, R.C.; Blood, F.B.

1983-05-01

The Torbett-Hutchings-Smith Memorial Hospital geothermal heating project, which is one of nineteen direct-use geothermal projects funded principally by DOE, is documented. The five-year project encompassed a broad range of technical, institutional, and economic activities including: resource and environmental assessments; well drilling and completion; system design, construction, and monitoring; economic analyses; public awareness programs; materials testing; and environmental monitoring. Some of the project conclusions are that: (1) the 155/sup 0/F Central Texas geothermal resource can support additional geothermal development; (2) private-sector economic incentives currently exist, especially for profit-making organizations, to develop and use this geothermal resource; (3) potential uses for this geothermal resource include water and space heating, poultry dressing, natural cheese making, fruit and vegetable dehydrating, soft-drink bottling, synthetic-rubber manufacturing, and furniture manufacturing; (4) high maintenance costs arising from the geofluid's scaling and corrosion tendencies can be avoided through proper analysis and design; (5) a production system which uses a variable-frequency drive system to control production rate is an attractive means of conserving parasitic pumping power, controlling production rate to match heating demand, conserving the geothermal resource, and minimizing environmental impacts.

Applications of Radiative Heating for Space Exploration

Science.gov (United States)

Brandis, Aaron

2017-01-01

Vehicles entering planetary atmospheres at high speeds (6 - 12 kms) experience intense heating by flows with temperatures of the order 10 000K. The flow around the vehicle experiences significant dissociation and ionization and is characterized by thermal and chemical non-equilibrium near the shock front, relaxing toward equilibrium. Emission from the plasma is intense enough to impart a significant heat flux on the entering spacecraft, making it necessary to predict the magnitude of radiative heating. Shock tubes represent a unique method capable of characterizing these processes in a flight-similar environment. The Electric Arc Shock tube (EAST) facility is one of the only facilities in its class, able to produce hypersonic flows at speeds up to Mach 50. This talk will review the characterization of radiation measured in EAST with simulations by the codes DPLR and NEQAIR, and in particular, focus on the impact these analyses have on recent missions to explore the solar system.

Utes for space heating and cooling in North Africa

International Nuclear Information System (INIS)

Nordell, B.; Grein, M. a.

2006-01-01

The North Africa climate is dry and warm with annual mean temperature from 15 degree centigrade to 25 degree centigrade, with a temperature difference of 20 degree centigrade between the coldest and warmest month. Heating is needed during the short winter and there is a large cooling demand during the long summer. Since the undisturbed ground temperature is equal to the annual mean air temperature, the ground is warmer than the air during the winter and colder than air during summer. This is what is required for the direct use of the ground for heating and cooling. In such systems, ground coupled heating and cooling systems, and also in storage systems, Underground Thermal Energy Storage (UTES), some kind of underground duct (PIPE) system is used to inject or extract heat from the ground. Thermal energy is then stored and recovered by heating and cooling of the ground, while the ducts are the heat exchangers with the system. The duct system could be placed horizontally or vertically (e.g. in boreholes) in the ground. In many cases heat pumps or cooling machines are included in the systems but in favourable cases, such as in the North African climate, the ground can be used directly for heating and cooling. then, only a circulation pump is used to pump water through the underground duct system with high efficiencies. Such systems can also be used for thermal energy storage, during shorter periods (diurnal) or even between the seasons. In September 2005 Sebha University and Luleu University of Technology started a Libyan Swedish collaboration to develop and implement these systems for the North African climate. Sweden has considerable experience in ground coupled systems, theoretically and practically, and there are presently more than 300.000 systems in operation in Sweden, mainly for heating. Most of these are small-scale heating systems for singe-family houses but during the last decade several hundred large-scale systems have been built for heating and cooling of

Heat pipes with variable thermal conductance property for space applications

Energy Technology Data Exchange (ETDEWEB)

Kravets, V.; Alekseik, Ye.; Alekseik, O.; Khairnasov, S. [National Technical University of Ukraine, Kyiv (Ukraine); Baturkin, V.; Ho, T. [Explorationssysteme RY-ES, Bremen (Germany); Celotti, L. [Active Space Technologies GmbH, Berlin (Germany)

2017-06-15

The activities presented in this paper demonstrate a new approach to provide passive thermal control using heat pipes, as demonstrated on the electronic unit of DLR’s MASCOT lander, which embarked on the NEA sample return mission Hayabusa 2 (JAXA). The focus is on the development and testing of heat pipes with variable thermal conductance in a predetermined temperature range. These heat pipes act as thermal switches. Unlike standard gasloaded heat pipes and thermal-diode heat pipes construction of presented heat pipes does not include any additional elements. Copper heat pipes with metal fibrous wicks were chosen as baseline design. We obtained positive results by choosing the heat carrier and structural parameters of the wick (i.e., pore diameter, porosity, and permeability). The increase in the thermal conductivity of the heat pipes from 0.04 W/K to 2.1 W/K was observed in the temperature range between −20 °C and +55 °C. Moreover, the heat pipes transferred the predetermined power of not less than 10 W within the same temperature range. The heat pipes have been in flight since December 2014, and the supporting telemetry data were obtained in September 2015. The data showed the nominal operation of the thermal control system.

Evaluating energy, health and carbon co-benefits from improved domestic space heating: A randomised community trial

International Nuclear Information System (INIS)

Preval, Nick; Chapman, Ralph; Pierse, Nevil; Howden-Chapman, Philippa

2010-01-01

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A - assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B - assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1.

Evaluating energy, health and carbon co-benefits from improved domestic space heating. A randomised community trial

Energy Technology Data Exchange (ETDEWEB)

Preval, Nick; Pierse, Nevil; Howden-Chapman, Philippa [He Kainga Oranga/Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South (New Zealand); Chapman, Ralph [School of Geography, Graduate Programme in Environmental Studies, Environment and Earth Sciences, Victoria University, PO Box 600, Wellington 6140 (New Zealand)

2010-08-15

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A - assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B - assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1. (author)

Evaluating energy, health and carbon co-benefits from improved domestic space heating: A randomised community trial

Energy Technology Data Exchange (ETDEWEB)

Preval, Nick [He Kainga Oranga/Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South (New Zealand); Chapman, Ralph, E-mail: Ralph.chapman@vuw.ac.n [School of Geography, Graduate Programme in Environmental Studies, Environment and Earth Sciences, Victoria University, PO Box 600, Wellington 6140 (New Zealand); Pierse, Nevil; Howden-Chapman, Philippa [He Kainga Oranga/Housing and Health Research Programme, University of Otago, Wellington, PO Box 7343, Wellington South (New Zealand)

2010-08-15

In order to value the costs and benefits associated with improved space heating we analysed the Housing, Heating and Health Study, a randomised community trial involving installation of energy efficient and healthy heaters (heat pump, wood pellet burner or flued gas heater) in homes with basic insulation and poor heating, occupied by households which included a child with asthma. We compared the initial purchase and installation cost of heaters with changes in the number of visits to health professionals, time off work/school, caregiving, and pharmaceutical use for household members and changes in total household energy use and carbon emissions following the intervention. We used two scenarios to analyse the results over the predicted 12-year life-span of the heaters. The targeted approach (Scenario A - assuming high rates of household asthma throughout the period of analysis) produced enough health-related benefits to offset the cost of the heaters, and when total energy use and carbon emission savings were included in the analysis the ratio of benefits to costs was 1.09:1. The untargeted approach (Scenario B - assuming typical New Zealand asthma rates throughout the period of analysis) had a ratio of total benefits to costs of 0.31:1.

Non-parametric method for separating domestic hot water heating spikes and space heating

DEFF Research Database (Denmark)

Bacher, Peder; de Saint-Aubain, Philip Anton; Christiansen, Lasse Engbo

2016-01-01

In this paper a method for separating spikes from a noisy data series, where the data change and evolve over time, is presented. The method is applied on measurements of the total heat load for a single family house. It relies on the fact that the domestic hot water heating is a process generating...

Systems with a constant heat flux with applications to radiative heat transport across nanoscale gaps and layers

Science.gov (United States)

Budaev, Bair V.; Bogy, David B.

2018-06-01

We extend the statistical analysis of equilibrium systems to systems with a constant heat flux. This extension leads to natural generalizations of Maxwell-Boltzmann's and Planck's equilibrium energy distributions to energy distributions of systems with a net heat flux. This development provides a long needed foundation for addressing problems of nanoscale heat transport by a systematic method based on a few fundamental principles. As an example, we consider the computation of the radiative heat flux between narrowly spaced half-spaces maintained at different temperatures.

Heat transfer system

Science.gov (United States)

Not Available

1980-03-07

A heat transfer system for a nuclear reactor is described. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

Heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Harada, F; Yanagida, T; Fujie, K; Futawatari, H

1975-04-30

The purpose of this construction is the improvement of heat transfer in finned tube heat exchangers, and therefore the improvement of its efficiency or its output per unit volume. This is achieved by preventing the formation of flow boundary layers in gaseous fluid. This effect always occurs on flow of smooth adjacent laminae, and especially if these have pipes carrying liquid passing through them; it worsens the heat transfer of such a boundary layer considerably compared to that in the turbulent range. The fins, which have several rows of heat exchange tubes passing through them, are fixed at a small spacing on theses tubes. The fins have slots cut in them by pressing or punching, where the pressed-out material remains as a web, which runs parallel to the level of the fin and at a small distance from it. These webs and slots are arranged radially around every tube hole, e.g. 6 in number. For a suitable small tube spacing, two adjacent tubes opposite each other have one common slot. Many variants of such slot arrangements are illustrated.

Absorption heat pump for space applications

Science.gov (United States)

Nguyen, Tuan; Simon, William E.; Warrier, Gopinath R.; Woramontri, Woranun

1993-01-01

In the first part, the performance of the Absorption Heat Pump (AHP) with water-sulfuric acid and water-magnesium chloride as two new refrigerant-absorbent fluid pairs was investigated. A model was proposed for the analysis of the new working pairs in a heat pump system, subject to different temperature lifts. Computer codes were developed to calculate the Coefficient of Performance (COP) of the system with the thermodynamic properties of the working fluids obtained from the literature. The study shows the potential of water-sulfuric acid as a satisfactory replacement for water-lithium bromide in the targeted temperature range. The performance of the AHP using water-magnesium chloride as refrigerant-absorbent pair does not compare well with those obtained using water-lithium bromide. The second part concentrated on the design and testing of a simple ElectroHydrodynamic (EHD) Pump. A theoretical design model based on continuum electromechanics was analyzed to predict the performance characteristics of the EHD pump to circulate the fluid in the absorption heat pump. A numerical method of solving the governing equations was established to predict the velocity profile, pressure - flow rate relationship and efficiency of the pump. The predicted operational characteristics of the EHD pump is comparable to that of turbomachinery hardware; however, the overall efficiency of the electromagnetic pump is much lower. An experimental investigation to verify the numerical results was conducted. The pressure - flow rate performance characteristics and overall efficiency of the pump obtained experimentally agree well with the theoretical model.

Residential solar-heating system

Science.gov (United States)

1978-01-01

Complete residential solar-heating and hot-water system, when installed in highly-insulated energy-saver home, can supply large percentage of total energy demand for space heating and domestic hot water. System which uses water-heating energy storage can be scaled to meet requirements of building in which it is installed.

Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings

DEFF Research Database (Denmark)

Harrestrup, Maria; Svendsen, S.

2014-01-01

is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized......The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce...... the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper...

Development of a nonazeotropic heat pump for crew hygiene water heating

Science.gov (United States)

Walker, David H.; Deming, Glenn I.

1991-01-01

A heat pump system is currently under development to produce hot water for crew hygiene on future manned space missions. The heat pump uses waste heat sources and a nonazeotropic working fluid in a highly efficient cycle. The potential benefits include a reduction in peak power draw from 2 to 5 kW for electric cartridge heaters to just more than 100 W for the heat pump. As part of the heat pump development project, a unique high efficiency compressor was developed to maintain lubrication in a zero-gravity environment.

A solar combi-system based on a heat exchanger between the collector loop and space-heating loop (IEA task 26 generic system 2). A report of IEA SHC - task 26 solar combisystems

International Nuclear Information System (INIS)

Ellehauge, K.

2002-12-01

The most common Danish solar combi-system is theoretically investigated in the report. The principle in the system is that in a normal solar hot water system a heat exchanger is added to deliver solar energy from the collector loop directly to the space heating loop. In this way solar energy for space heating is not stored which is expected to decrease the performance. On the other hand the system is relatively inexpensive, which can compensate for a reduced performance. A TRNSYS model of the system is developed and sensitivity analyses of parameters are performed by simulation. The analyses show no major improvements of the system. Special emphasis has been put on investigating the control strategy and to investigate if the thermal mass of radiators of floor could act as buffer for the solar energy delivered to space heating and in this way improve the performance. The analyses show that this is possible and has advantages at larger collector areas. However the improvements are not as large as expected. An economic optimisation gives and optimum solar collector area of approximately 10 m 2 . However the optimum curve is quite flat for areas above 7 m 2 , and collector areas up to 15 m 2 are also feasible. The calculated performacnes have been the basis for comparisons with the other systems modelled in the task 26. The comparison shows that the performance is not among the best, but however probably not as bad as expected. Furthermore the inexpensive design compensates to some extent for the lower performance. Furthermore the material use of the system and the energy used to produce the materials has been estimated. The energy demand is in a range that gives energy pay back times of 1.9-2.5 years. (au)

What Is Heat? Inquiry regarding the Science of Heat

Science.gov (United States)

Rascoe, Barbara

2010-01-01

This lab activity uses inquiry to help students define heat. It is generic in that it can be used to introduce a plethora of science content across middle and high school grade levels and across science disciplines that include biology, Earth and space science, and physical science. Even though heat is a universal science phenomenon that is…

Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

Science.gov (United States)

Paul, Heather L.; Sompayrac, Robert; Conger, Bruce; Chamberlain, Mateo

2009-01-01

As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

Remote control systems for space heating. Product overview 2010 and recommendations - Final report; Fernsteuerungen fuer Raumheizungen. Produktuebersicht 2010 und Empfehlungen - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Geilinger, E.; Bush, E. [Bush Energie GmbH, Felsberg (Switzerland); Venzin, T. [Hochschule fuer Technik und Wirtschaft (HTW) Chur, Chur (Switzerland); Nipkow, J. [Arena, Zuerich (Switzerland)

2010-09-15

Saving space heating energy by remote control: A remote-controlled space heating system allows a person to lower the room temperature in homes that go unoccupied for periods of time to the lowest temperature that's safe to keep the pipes from freezing while they're away. Comfort is guaranteed because the desired room temperature or mode can be activated in time before the guests arrive, via text message, phone or the internet. As most people simply leave unoccupied homes heated, the remote-controlled system saves up to 70% of heating energy when used actively. Market overview and product features: This report presents remote control devices that are currently available on the market. Their advantages and disadvantages are discussed as well as their technical features and function. Most of them are universal remote controls that have various uses, including temperature control. The report also discusses requirements that not all the examined products meet. Some lack an emergency power supply, the possibility for manual control or the ability to check the current temperature of the home from a remote location. Better planning for remote control: The critical issue proved not to be the remote control device itself, but the heating systems. Unfortunately, they often don't provide an option to be extended by remote control. We therefore call on the manufacturers to equip all new heating systems with options for remote control. It would also be helpful and desirable to provide information on the internet or in the technical documentation on how to connect a remote control device and which products are suitable - both for existing and new heating systems. If the system cannot be retrofitted, it should be described whether and how a central remote control with room thermostat can be installed. Improving communication: In this study, remote control and heating suppliers were interviewed as well as planners, installers and users of remote-controlled heating

Comprehensive report of aeropropulsion, space propulsion, space power, and space science applications of the Lewis Research Center

Science.gov (United States)

1988-01-01

The research activities of the Lewis Research Center for 1988 are summarized. The projects included are within basic and applied technical disciplines essential to aeropropulsion, space propulsion, space power, and space science/applications. These disciplines are materials science and technology, structural mechanics, life prediction, internal computational fluid mechanics, heat transfer, instruments and controls, and space electronics.

Solar heat gain through vertical cylindrical glass

Energy Technology Data Exchange (ETDEWEB)

Kassem, M.A.; Kaseb, S.; El-Refaie, M.F. [Cairo Univ., Mechanical Power Engineering Dept., Cairo (Egypt)

1999-10-01

Spaces with nonplanar glazed envelopes are frequently encountered in contemporary buildings. Such spaces represent a problem when calculating the solar heat gain in the course of estimating the cooling or heating load; and hence, sizing of cooling or heating systems. The calculation, using the information currently available in the literature, is tedious and/or approximate. In the present work, the computational procedure for evaluating the solar heat gain to a space having a vertical cylindrical glass envelope is established, and, a computer program is coded to carry out the necessary computations and yield the results in a detailed usable form. The program is versatile and allows for the arbitrary variation of all pertinent parameters. (Author)

Solar heat gain through vertical cylindrical glass

International Nuclear Information System (INIS)

Kassem, M.A.; Kaseb, S.; El-Refaie, M.F.

1999-01-01

Spaces with nonplanar glazed envelopes are frequently encountered in contemporary buildings. Such spaces represent a problem when calculating the solar heat gain in the course of estimating the cooling or heating load; and hence, sizing of cooling or heating systems. The calculation, using the information currently available in the literature, is tedious and/or approximate. In the present work, the computational procedure for evaluating the solar heat gain to a space having a vertical cylindrical glass envelope is established, and, a computer program is coded to carry out the necessary computations and yield the results in a detailed usable form. The program is versatile and allows for the arbitrary variation of all pertinent parameters. (Author)

Solar heat gain through vertical cylindrical glass

Energy Technology Data Exchange (ETDEWEB)

Kassem, M.A.; Kaseb, S.; El-Refaie, M.F. [Cairo Univ., Mechanical Power Engineering Dept., Cairo (Egypt)

1999-07-01

Spaces with nonplanar glazed envelopes are frequently encountered in contemporary buildings. Such spaces represent a problem when calculating the solar heat gain in the course of estimating the cooling or heating load; and hence, sizing of cooling or heating systems. The calculation, using the information currently available in the literature, is tedious and/or approximate. In the present work, the computational procedure for evaluating the solar heat gain to a space having a vertical cylindrical glass envelope is established, and, a computer program is coded to carry out the necessary computations and yield the results in a detailed usable form. The program is versatile and allows for the arbitrary variation of all pertinent parameters. (Author)

Sterilization of space hardware.

Science.gov (United States)

Pflug, I. J.

1971-01-01

Discussion of various techniques of sterilization of space flight hardware using either destructive heating or the action of chemicals. Factors considered in the dry-heat destruction of microorganisms include the effects of microbial water content, temperature, the physicochemical properties of the microorganism and adjacent support, and nature of the surrounding gas atmosphere. Dry-heat destruction rates of microorganisms on the surface, between mated surface areas, or buried in the solid material of space vehicle hardware are reviewed, along with alternative dry-heat sterilization cycles, thermodynamic considerations, and considerations of final sterilization-process design. Discussed sterilization chemicals include ethylene oxide, formaldehyde, methyl bromide, dimethyl sulfoxide, peracetic acid, and beta-propiolactone.

Phase Change Material Heat Exchanger Life Test

Science.gov (United States)

Lillibridge, Sean; Stephan, Ryan

2009-01-01

Low Lunar Orbit (LLO) poses unique thermal challenges for the orbiting space craft, particularly regarding the performance of the radiators. The IR environment of the space craft varies drastically from the light side to the dark side of the moon. The result is a situation where a radiator sized for the maximal heat load in the most adverse situation is subject to freezing on the dark side of the orbit. One solution to this problem is to implement Phase Change Material (PCM) Heat Exchangers. PCM Heat Exchangers act as a "thermal capacitor," storing thermal energy when there is too much being produced by the space craft to reject to space, and then feeding that energy back into the thermal loop when conditions are more favorable. Because they do not use an expendable resource, such as the feed water used by sublimators and evaporators, PCM Heat Exchangers are ideal for long duration LLO missions. In order to validate the performance of PCM Heat Exchangers, a life test is being conducted on four n-Pentadecane, carbon filament heat exchangers. Fluid loop performance, repeatability, and measurement of performance degradation over 2500 melt-freeze cycles will be performed.

Optimization of Solar Water Heating System under Time and Spatial Partition Heating in Rural Dwellings

Directory of Open Access Journals (Sweden)

Yanfeng Liu

2017-10-01

Full Text Available This paper proposes the application of time and spatial partition heating to a solar water heating system. The heating effect and system performance were analyzed under the continuous and whole space heating and time and spatial partition heating using TRNSYS. The results were validated by comparing with the test results of the demonstration building. Compared to continuous and whole space heating, the use of time and spatial partition heating increases the solar fraction by 16.5%, reduces the auxiliary heating by 7390 MJ, and reduces the annual operation cost by 2010 RMB. Under time and spatial partition heating, optimization analyses were conducted for the two system capacity parameters of the solar collector area and tank volume and the one operation parameter of auxiliary heater setting outlet temperature. The results showed that a reasonable choice of the solar collector area can reduce the dynamic annual cost, the increased tank volume is advantageous to heat storage, and the auxiliary heater setting outlet temperature have greater influence on the indoor heating effect. The advanced opening of solar water heating system and the normal opening of passive air vents are recommended. Based on the comparison of the two modes, the time and spatial partition heating technology is a better choice for rural dwellings.

Deep freezers with heat recovery

Energy Technology Data Exchange (ETDEWEB)

Kistler, J.

1981-09-02

Together with space and water heating systems, deep freezers are the biggest energy consumers in households. The article investigates the possibility of using the waste heat for water heating. The design principle of such a system is presented in a wiring diagram.

Lab-scale experiment of a closed thermochemical heat storage system including honeycomb heat exchanger

International Nuclear Information System (INIS)

Fopah-Lele, Armand; Rohde, Christian; Neumann, Karsten; Tietjen, Theo; Rönnebeck, Thomas; N'Tsoukpoe, Kokouvi Edem; Osterland, Thomas; Opel, Oliver

2016-01-01

A lab-scale thermochemical heat storage reactor was developed in the European project “thermal battery” to obtain information on the characteristics of a closed heat storage system, based on thermochemical reactions. The present type of storage is capable of re-using waste heat from cogeneration system to produce useful heat for space heating. The storage material used was SrBr 2 ·6H 2 O. Due to agglomeration or gel-like problems, a structural element was introduced to enhance vapour and heat transfer. Honeycomb heat exchanger was designed and tested. 13 dehydration-hydration cycles were studied under low-temperature conditions (material temperatures < 100 °C) for storage. Discharging was realized at water vapour pressure of about 42 mbar. Temperature evolution inside the reactor at different times and positions, chemical conversion, thermal power and overall efficiency were analysed for the selected cycles. Experimental system thermal capacity and efficiency of 65 kWh and 0.77 are respectively obtained with about 1 kg of SrBr 2 ·6H 2 O. Heat transfer fluid recovers heat at a short span of about 43 °C with an average of 22 °C during about 4 h, acceptable temperature for the human comfort (20 °C on day and 16 °C at night). System performances were obtained for a salt bed energy density of 213 kWh·m 3 . The overall heat transfer coefficient of the honeycomb heat exchanger has an average value of 147 W m −2  K −1 . Though promising results have been obtained, ameliorations need to be made, in order to make the closed thermochemical heat storage system competitive for space heating. - Highlights: • Lab-scale thermochemical heat storage is designed, constructed and tested. • The use of honeycomb heat exchanger as a heat and vapour process enhancement. • Closed system (1 kg SrBr 2 ·6H 2 O) able to give back 3/4 of initial thermal waste energy. • System storage capacity and thermal efficiency are respectively 65 kWh and 0.77. �

Experimental results of acetone hydrogenation on a heat exchanger type reactor for solar chemical heat pump; Solar chemical heat pump ni okeru acetone suisoka hanno netsu kaishu jikken

Energy Technology Data Exchange (ETDEWEB)

Takashima, T; Doi, T; Tanaka, T; Ando, Y [Electrotechnical Laboratory, Tsukuba (Japan); Miyahara, R; Kamoshida, J [Shibaura Institute of Technology, Tokyo (Japan)

1996-10-27

With the purpose of converting solar heat energy to industrial heat energy, an experiment of acetone hydrogenation was carried out using a heat exchanger type reactor that recovers heat generated by acetone hydrogenation, an exothermic reaction, and supplies it to an outside load. In the experiment, a pellet-like activated carbon-supported ruthenium catalyst was used for the acetone hydrogenation with hydrogen and acetone supplied to the catalyst layer at a space velocity of 400-1,200 or so. In the external pipe of the double-pipe type reactor, a heating medium oil was circulated in parallel with the flow of the reactant, with the heat of reaction recovered that was generated from the acetone hydrogenation. In this experiment, an 1wt%Ru/C catalyst and a 5wt%Ru/C catalyst were used so as to examine the effects of variation in the space velocity. As a result, from the viewpoint of recovering the heat of reaction, it was found desirable to increase the reaction speed by raising catalytic density and also to supply the reactant downstream inside the reaction pipe by increasing the space velocity. 1 ref., 6 figs., 1 tab.

High temperature heat pipe experiments in low earth orbit

International Nuclear Information System (INIS)

Woloshun, K.; Merrigan, M.A.; Sena, J.T.; Critchley, E.

1993-01-01

Although high temperature, liquid metal heat pipe radiators have become a standard component on most high power space power system designs, there is no experimental data on the operation of these heat pipes in a zero gravity or micro-gravity environment. Experiments to benchmark the transient and steady state performance of prototypical heat pipe space radiator elements are in preparation for testing in low earth orbit. It is anticipated that these heat pipes will be tested aborad the Space Shuttle in 1995. Three heat pipes will be tested in a cargo bay Get Away Special (GAS) canister. The heat pipes are SST/potassium, each with a different wick structure; homogeneous, arterial, and annular gap, the heat pipes have been designed, fabricated, and ground tested. In this paper, the heat pipe designs are specified, and transient and steady-state ground test data are presented

Solar-Heated and Cooled Office Building--Columbus, Ohio

Science.gov (United States)

1982-01-01

Final report documents solar-energy system installed in office building to provide space heating, space cooling and domestic hot water. Collectors mounted on roof track Sun and concentrate rays on fluid-circulating tubes. Collected energy is distributed to hot-water-fired absorption chiller and space-heating and domestic-hot-water preheating systems.

Heat recovery in industry

Energy Technology Data Exchange (ETDEWEB)

Steimle, F; Paul, J [Essen Univ. (Gesamthochschule) (Germany, F.R.)

1977-05-01

The waste heat of industrial furnaces and other heat-consuming installations can be utilized by recuperative processes in the furnace and by energy cascades. Economy and the need for an external supply of energy are closely connected. Straight cascades can hardly be realized and if the required temperature gradient is too great such heat should be utilized repeatedly if possible by recycling through heat pumps. The possibilities depend on the relevant temperature since the technology available for this differs in its state of development. The low-temperature waste heat from the final stage can be used for space-heating and water heating by heat exchangers and heat pumps and thus be put to a useful purpose.

Simulation of the impact of financial incentives on solar energy utilization for space conditioning and water heating: 1985

Energy Technology Data Exchange (ETDEWEB)

Petersen, H C

1979-01-01

Financial incentives designed to accelerate the use of solar energy for heating, cooling, and water heating of buildings have been proposed by both state and federal legislative bodies in the U.S.A. Among the most frequently mentioned incentives are sales and property tax exemptions, tax deductions and credits, rapid amortization provisions, and interest rate subsidies. At the present time there is little available information regarding the ability of such incentives to advance the rate of solar energy utilization. This paper describes the derivation and use of a computer simulation model designed to estimate solar energy use for space conditioning and water heating for given economic, climatic, and technological conditions. When applied to data from the Denver, Colorado metropolitan area, the simulation model predicts that sales tax exemptions would have little impact over the next decade, interest rate subsidies could more than double solar energy use, and the other proposed incentives would have an intermediate impact.

Marangoni convection in Casson liquid flow due to an infinite disk with exponential space dependent heat source and cross-diffusion effects

Science.gov (United States)

Mahanthesh, B.; Gireesha, B. J.; Shashikumar, N. S.; Hayat, T.; Alsaedi, A.

2018-06-01

Present work aims to investigate the features of the exponential space dependent heat source (ESHS) and cross-diffusion effects in Marangoni convective heat mass transfer flow due to an infinite disk. Flow analysis is comprised with magnetohydrodynamics (MHD). The effects of Joule heating, viscous dissipation and solar radiation are also utilized. The thermal and solute field on the disk surface varies in a quadratic manner. The ordinary differential equations have been obtained by utilizing Von Kármán transformations. The resulting problem under consideration is solved numerically via Runge-Kutta-Fehlberg based shooting scheme. The effects of involved pertinent flow parameters are explored by graphical illustrations. Results point out that the ESHS effect dominates thermal dependent heat source effect on thermal boundary layer growth. The concentration and temperature distributions and their associated layer thicknesses are enhanced by Marangoni effect.

Compact seasonal PCM heat storage for solar heating systems

DEFF Research Database (Denmark)

Dannemand, Mark

Space heating of buildings and preparation of domestic hot water accounts for a large part of the society’s energy consumption. Solar radiation is an abundant and renewable energy source which can be harvested by solar collectors and used to cover heating demands in the built environment....... The seasonal availability of solar energy does however not match with the heating demands in buildings which typically are large in winter periods when limited solar energy is available. Heat can be stored over a few days in water stores but continuous heat losses limits the storage periods. The possibility...... of storing heat from summer where solar energy is widely available to winter periods where the heating demands are large, allows for implementing more renewable energy in our energy system. The phase change material (PCM) sodium acetate trihydrate (SAT) melts at 58 °C. The melting process requires...

Monitoring of Danish marketed solar heating systems

International Nuclear Information System (INIS)

Ellehauge, K.

1993-01-01

The paper describes the monitoring of manufactured solar heating systems for domestic hot water combined with space heating and systems for domestic hot water only. Results from the monitoring of 5 marketed combined systems for domestic hot water and space heating are presented. The systems situated at one family houses at different sites in Denmark have been monitored from January/February 1992. For the detailed monitoring of manufactured systems only for domestic hot water a test facility for simultaneous monitoring of 5 solar heating systems has been established at the Thermal Insulation Laboratory. (au)

Solar systems and heat pumps in operation in Carinthia: results 1994 - 1997

International Nuclear Information System (INIS)

Faninger, G.

1998-04-01

Solar systems and heat pumps in operation in Carinthia: results 1994 - 1997. Test results from solar systems for swimming pool heating, hot water preparation and space heating as well as heat pumps for hot water preparation, space heating and heat recovery will be reported and assessed collectively. (author)

Cold local heating. Agrothermal heat supply of an ecovillage; Kalt Nahwaerme. Agrothermische Waermeversorgung einer Plusenergiesiedlung

Energy Technology Data Exchange (ETDEWEB)

Pietruschka, Dirk [Hochschule fuer Technik Stuttgart (Germany). Forschungszentrum fuer Nachhaltige Energietechnik; Kluge, Juergen [Doppelacker GmbH, Petershagen-Eggersdorf (Germany)

2013-03-01

An ecovillage with highly efficient residential buildings is arisen in the Swabian community Wuestenrot. The power generation in these residential buildings by means of photovoltaic power plants is greater than the energy consumption. Decentralized heat plants supply thermal energy for the space heating and industrial waste. Central agrothermal collectors provide the necessary low-temperature heat for the effective operation of heat pumps over a so-called cold heat grid.

Combination solar photovoltaic heat engine energy converter

Science.gov (United States)

Chubb, Donald L.

1987-01-01

A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

Heat exchangers

International Nuclear Information System (INIS)

1975-01-01

The tubes of a heat exchanger tube bank have a portion thereof formed in the shape of a helix, of effective radius equal to the tube radius and the space between two adjacent tubes, to tangentially contact the straight sections of the tubes immediately adjacent thereto and thereby provide support, maintain the spacing and account for differential thermal expansion thereof

Thermal-Flow Code for Modeling Gas Dynamics and Heat Transfer in Space Shuttle Solid Rocket Motor Joints

Science.gov (United States)

Wang, Qunzhen; Mathias, Edward C.; Heman, Joe R.; Smith, Cory W.

2000-01-01

A new, thermal-flow simulation code, called SFLOW. has been developed to model the gas dynamics, heat transfer, as well as O-ring and flow path erosion inside the space shuttle solid rocket motor joints by combining SINDA/Glo, a commercial thermal analyzer. and SHARPO, a general-purpose CFD code developed at Thiokol Propulsion. SHARP was modified so that friction, heat transfer, mass addition, as well as minor losses in one-dimensional flow can be taken into account. The pressure, temperature and velocity of the combustion gas in the leak paths are calculated in SHARP by solving the time-dependent Navier-Stokes equations while the heat conduction in the solid is modeled by SINDA/G. The two codes are coupled by the heat flux at the solid-gas interface. A few test cases are presented and the results from SFLOW agree very well with the exact solutions or experimental data. These cases include Fanno flow where friction is important, Rayleigh flow where heat transfer between gas and solid is important, flow with mass addition due to the erosion of the solid wall, a transient volume venting process, as well as some transient one-dimensional flows with analytical solutions. In addition, SFLOW is applied to model the RSRM nozzle joint 4 subscale hot-flow tests and the predicted pressures, temperatures (both gas and solid), and O-ring erosions agree well with the experimental data. It was also found that the heat transfer between gas and solid has a major effect on the pressures and temperatures of the fill bottles in the RSRM nozzle joint 4 configuration No. 8 test.

Pulse-echo ultrasonic inspection system for in-situ nondestructive inspection of Space Shuttle RCC heat shields.

Energy Technology Data Exchange (ETDEWEB)

Roach, Dennis Patrick; Walkington, Phillip D.; Rackow, Kirk A.

2005-06-01

The reinforced carbon-carbon (RCC) heat shield components on the Space Shuttle's wings must withstand harsh atmospheric reentry environments where the wing leading edge can reach temperatures of 3,000 F. Potential damage includes impact damage, micro cracks, oxidation in the silicon carbide-to-carbon-carbon layers, and interlaminar disbonds. Since accumulated damage in the thick, carbon-carbon and silicon-carbide layers of the heat shields can lead to catastrophic failure of the Shuttle's heat protection system, it was essential for NASA to institute an accurate health monitoring program. NASA's goal was to obtain turnkey inspection systems that could certify the integrity of the Shuttle heat shields prior to each mission. Because of the possibility of damaging the heat shields during removal, the NDI devices must be deployed without removing the leading edge panels from the wing. Recently, NASA selected a multi-method approach for inspecting the wing leading edge which includes eddy current, thermography, and ultrasonics. The complementary superposition of these three inspection techniques produces a rigorous Orbiter certification process that can reliably detect the array of flaws expected in the Shuttle's heat shields. Sandia Labs produced an in-situ ultrasonic inspection method while NASA Langley developed the eddy current and thermographic techniques. An extensive validation process, including blind inspections monitored by NASA officials, demonstrated the ability of these inspection systems to meet the accuracy, sensitivity, and reliability requirements. This report presents the ultrasonic NDI development process and the final hardware configuration. The work included the use of flight hardware and scrap heat shield panels to discover and overcome the obstacles associated with damage detection in the RCC material. Optimum combinations of custom ultrasonic probes and data analyses were merged with the inspection procedures needed to

Effects of Green Space and Land Use/Land Cover on Urban Heat Island in a Subtropical Mega-city in China

Science.gov (United States)

Qiu, G. Y.; Li, X.; Li, H.; Guo, Q.

2014-12-01

With the quick expansion of urban in size and population, its urban heat island intensity (UHII, expressed as the temperature difference between urban and rural areas) increased rapidly. However, very few studies could quantitatively reveal the effects of green space and land use/land cover (LULC) on urban thermal environment because of lacking of the detailed measurement. This study focuses on quantifying the effects of green space and LULC on urban Heat Island (UHI) in Shenzhen, a mega subtropical city in China. Extensive measurements (air temperature and humidity) were made by mobile traverse method in a transect of 8 km in length, where a variety of LULC types were included. Measurements were carried out at 2 hours interval for 2 years (totally repeated for 7011 times). According to LULC types, we selected 5 different LULC types for studying, including water body, village in the city, shopping center (commercial area), urban green space (well-vegetated area) and suburb (forest). The main conclusions are obtained as follows: (1) The temperature difference between the 5 different urban landscapes is obvious, i.e. shopping center > village in the city > urban water body > urban green space > suburb; (2) Air temperature and UHII decreases linearly with the increase of green space in urban; (3) Green space and water body in urban have obvious effects to reduce the air temperature by evapotranspiration. Compared to the commercial areas, urban water body can relieve the IUHI by 0.9℃, while the urban green space can relieve the IUHI by 1.57℃. The cooling effect of the urban green space is better than that of the urban water body; (4) Periodic activity of human being has obvious effects on urban air temperature. The UHII on Saturday and Sunday are higher than that from Monday to Friday, respectively higher for 0.65, 0.57, 0.26 and 0.21℃. Thursday and Friday have the minimum air temperature and UHII. These results indicate that increase in urban evapotranspiration

Review of liquid metal heat pipe work at Los Alamos

International Nuclear Information System (INIS)

Reid, R.S.; Merrigan, M.A.; Sena, J.T.

1990-01-01

A survey of space-power related liquid metal heat pipe work at Los Alamos National Laboratory is presented. Heat pipe development at Los Alamos has been on-going since 1963. Heat pipes were initially developed for thermionic nuclear-electrical power production in space. Since then Los Alamos has developed liquid metal heat pipes for numerous applications related to high temperature systems in both the space and terrestrial environments. Some of these applications include thermionic electrical generators, thermoelectric energy conversion (both in-core and direct radiation), thermal energy storage, hypersonic vehicle leading edge cooling, and heat pipe vapor laser cells. Some of the work performed at Los Alamos has been documented in internal reports that are often little-known. A representative description and summary of progress in space-related liquid metal heat pipe technology is provided followed by a reference section citing sources where these works may be found. 53 refs

General-purpose heat source project and space nuclear safety fuels program. Progress report, February 1980

International Nuclear Information System (INIS)

Maraman, W.J.

1980-05-01

This formal monthly report covers the studies related to the use of 238 PuO 2 in radioisotopic power systems carried out for the Advanced Nuclear Systems and Projects Division of the Los Alamos Scientific Laboratory. The two programs involved are: General-Purpose Heat Source Development and Space Nuclear Safety and Fuels. Most of the studies discussed here are of a continuing nature. Results and conclusions described may change as the work continues. Published reference to the results cited in this report should not be made without the explicit permission of the person in charge of the work

Advanced radioisotope heat source for Stirling Engines

International Nuclear Information System (INIS)

Dobry, T.J.; Walberg, G.

2001-01-01

The heat exchanger on a Stirling Engine requires a thermal energy transfer from a heat source to the engine through a very limited area on the heater head circumference. Designing an effective means to assure maximum transfer efficiency is challenging. A single General Purpose Heat Source (GPHS), which has been qualified for space operations, would satisfy thermal requirements for a single Stirling Engine that would produce 55 electrical watts. However, it is not efficient to transfer its thermal energy to the engine heat exchanger from its rectangular geometry. This paper describes a conceptual design of a heat source to improve energy transfer for Stirling Engines that may be deployed to power instrumentation on space missions

Refrigerant charge management in a heat pump water heater

Science.gov (United States)

Chen, Jie; Hampton, Justin W.

2014-06-24

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.

46 CFR 32.40-50 - Heating and cooling-T/ALL.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Heating and cooling-T/ALL. 32.40-50 Section 32.40-50... REQUIREMENTS Accommodations for Officers and Crew § 32.40-50 Heating and cooling—T/ALL. (a) All manned spaces must be adequately heated and cooled in a manner suitable to the purpose of the space. (b) The heating...

Solar water heater for NASA's Space Station

Science.gov (United States)

Somers, Richard E.; Haynes, R. Daniel

1988-01-01

The feasibility of using a solar water heater for NASA's Space Station is investigated using computer codes developed to model the Space Station configuration, orbit, and heating systems. Numerous orbit variations, system options, and geometries for the collector were analyzed. Results show that a solar water heater, which would provide 100 percent of the design heating load and would not impose a significant impact on the Space Station overall design is feasible. A heat pipe or pumped fluid radial plate collector of about 10-sq m, placed on top of the habitat module was found to be well suited for satisfying water demand of the Space Station. Due to the relatively small area required by a radial plate, a concentrator is unnecessary. The system would use only 7 to 10 percent as much electricity as an electric water-heating system.

Heat Roadmap Europe 1

DEFF Research Database (Denmark)

Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg

2012-01-01

Heat Roadmap Europe (Pre-study 1) investigates the role of district heating in the EU27 energy system by mapping local conditions across Europe, identifying the potential for district heating expansion, and subsequently simulating the potential resource in an hourly model of the EU27 energy system....... In 2010, approximately 12% of the space heating demand in Europe is met by district heating, but in this study four alternative scenarios are considered for the EU27 energy system: 1. 2010 with 30% district heating 2. 2010 with 50% district heating 3. 2030 with 30% district heating 4. 2050 with 50......% district heating These scenarios are investigated in two steps. Firstly, district heating replaces individual boilers by converting condensing power plants to combined heat and power plants (CHP) to illustrate how district heating improves the overall efficiency of the energy system. In the second step...

Cyro Power and Heat Transfer

National Research Council Canada - National Science Library

Chow, L

1998-01-01

.... The heat generated from a 9x9-heater array was removed by liquid nitrogen pool boiling. The orientation and space limitation of the array were varied to explore their effects on the critical heat flux (CHF) value...

Measuring space radiation shielding effectiveness

Directory of Open Access Journals (Sweden)

Bahadori Amir

2017-01-01

Full Text Available Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

Measuring space radiation shielding effectiveness

Science.gov (United States)

Bahadori, Amir; Semones, Edward; Ewert, Michael; Broyan, James; Walker, Steven

2017-09-01

Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

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

Directory of Open Access Journals (Sweden)

V. I. Solonin

2014-01-01

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

Solar thermal heating and cooling. A bibliography with abstracts

Science.gov (United States)

Arenson, M.

1979-01-01

This bibliographic series cites and abstracts the literature and technical papers on the heating and cooling of buildings with solar thermal energy. Over 650 citations are arranged in the following categories: space heating and cooling systems; space heating and cooling models; building energy conservation; architectural considerations, thermal load computations; thermal load measurements, domestic hot water, solar and atmospheric radiation, swimming pools; and economics.

Electron velocity-space diffusion in a micro-unstable ECRH [electron cyclotron resonance heated] mirror plasma

International Nuclear Information System (INIS)

Hokin, S.A.

1987-09-01

An experimental study of the velocity-space diffusion of electrons in an electron cyclotron resonance heated (ECRH) mirror plasma, in the presence of micro-unstable whistler rf emission, is presented. It is found that the dominant loss mechanism for hot electrons is endloss produced by rf diffusion into the mirror loss cone. In a standard case with 4.5 kW of ECRH power, this loss limits the stored energy to 120 J with an energy confinement time of 40 ms. The energy confinement time associated with collisional scattering is 350 ms in this case. Whistler microinstability rf produces up to 25% of the rf-induced loss. The hot electron temperature is not limited by loss of adiabaticity, but by rf-induced loss of high energy electrons, and decreases with increasing rf power in strong diffusion regimes. Collisional loss is in agreement with standard scattering theory. No super-adiabatic effects are clearly seen. Experiments in which the vacuum chamber walls are lined with microwave absorber reveal that single pass absorption is limited to less than 60%, whereas experiments with reflecting walls exhibit up to 90% absorption. Stronger diffusion is seen in the latter, with a hot electron heating rate which is twice that of the absorber experiments. This increase in diffusion can be produced by two distinct aspects of wall-reflected rf: the broader spatial rf profile, which enlarges the resonant region in velocity space, or a reduction in super-adiabatic effects due to randomization of the electron gyrophase. Since no other aspects of super-adiabaticity are observed, the first mechanism appears more likely. 39 refs., 54 figs

A Computational Fluid Dynamic and Heat Transfer Model for Gaseous Core and Gas Cooled Space Power and Propulsion Reactors

Science.gov (United States)

Anghaie, S.; Chen, G.

1996-01-01

A computational model based on the axisymmetric, thin-layer Navier-Stokes equations is developed to predict the convective, radiation and conductive heat transfer in high temperature space nuclear reactors. An implicit-explicit, finite volume, MacCormack method in conjunction with the Gauss-Seidel line iteration procedure is utilized to solve the thermal and fluid governing equations. Simulation of coolant and propellant flows in these reactors involves the subsonic and supersonic flows of hydrogen, helium and uranium tetrafluoride under variable boundary conditions. An enthalpy-rebalancing scheme is developed and implemented to enhance and accelerate the rate of convergence when a wall heat flux boundary condition is used. The model also incorporated the Baldwin and Lomax two-layer algebraic turbulence scheme for the calculation of the turbulent kinetic energy and eddy diffusivity of energy. The Rosseland diffusion approximation is used to simulate the radiative energy transfer in the optically thick environment of gas core reactors. The computational model is benchmarked with experimental data on flow separation angle and drag force acting on a suspended sphere in a cylindrical tube. The heat transfer is validated by comparing the computed results with the standard heat transfer correlations predictions. The model is used to simulate flow and heat transfer under a variety of design conditions. The effect of internal heat generation on the heat transfer in the gas core reactors is examined for a variety of power densities, 100 W/cc, 500 W/cc and 1000 W/cc. The maximum temperature, corresponding with the heat generation rates, are 2150 K, 2750 K and 3550 K, respectively. This analysis shows that the maximum temperature is strongly dependent on the value of heat generation rate. It also indicates that a heat generation rate higher than 1000 W/cc is necessary to maintain the gas temperature at about 3500 K, which is typical design temperature required to achieve high

Phase-space resolved measurement of 2nd harmonic ion cyclotron heating using FIDA tomography at the ASDEX Upgrade tokamak

DEFF Research Database (Denmark)

Weiland, M.; Bilato, R.; Geiger, B.

2017-01-01

Recent upgrades to the FIDA (fast-ion D-alpha) diagnostic at ASDEX Upgrade allow to reconstruct the fast-ion phase space at several radial positions with decent energy and pitch resolution. These new diagnostic capabilities are applied to study the physics of 2nd harmonic ion cyclotron heating, w....... Furthermore, comparisons to other fast-ion diagnostics (neutron yield and neutral particle analyzers) are discussed....

The effect of heat generation in inclined slats on the natural convective heat transfer from an isothermal heated vertical plate

International Nuclear Information System (INIS)

Oosthuizen, P.H.; Sun, L.; Naylor, D.

2003-01-01

Natural convective heat transfer from a wide heated vertical isothermal plate with adiabatic surfaces above and below the heated surface has been considered. There are a series of equally spaced vertical thin, flat surfaces (termed 'slats') near the heated surface, these surfaces being, in general, inclined to the heated surface. There is, in general, a uniform heat generation in the slats. The slats are pivoted about their centre-point and thus as their angle is changed, the distance of the tip of the slat from the plate changes. The situation considered is an approximate model of a window with a vertical blind, the particular case where the window is hotter than the room air being considered. The heat generation in the slats in this situation is the result of solar radiation passing through the window and falling on and being absorbed by the slats of the blind. The flow has been assumed to be laminar and steady. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces. The governing equations have been written in dimensionless form and the resulting dimensionless equations have been solved using a commercial finite-element package. The solution has the following parameters: (1) the Rayleigh number (2) the Prandtl number (3) the dimensionless heat generation rate in the slats per unit frontal area (4) the dimensionless distance of the slat center point (the pivot point) from the surface (5) the dimensionless slat size (6) the dimensionless slat spacing (7) the angle of inclination of the slats. Because of the application that motivated the study, results have only been obtained for a Prandtl number of 0.7. The effect of the other dimensionless variables on the mean dimensionless heat transfer rate from the heated vertical surface has been examined. (author)

Solar heating for an electronics manufacturing plant--Blue Earth, Minnesota

Science.gov (United States)

1981-01-01

Partial space heating for 97,000 square foot plant is supplied by 360 flat plate solar collectors; energy is sorted as heat in indoor 20,000 gallon water tank. System includes all necessary control electronics for year round operation. During December 1978, solar energy supplied 24.4 percent of building's space heating load.

The space heating market and the big customers; Vaermemarknaden och storkunderna

Energy Technology Data Exchange (ETDEWEB)

Maardsjoe, Olle

2007-07-01

This report focuses on the cost of heating in multiple-occupancy buildings, commercial premises and industrial premises. A summary has been created of the development of heating, primarily in the 2000s, for as long as statistics are available (essentially 2004). Total heating has seen a reduction over the period as regards both total usage and specifically in kWh/sq. m. District heating, on the other hand, has seen an increase in total turnover, now accounting for around two-thirds of demand - or about 42 TWh - as well. The increase in district heating has come about partly as a result of property renovation and people exchanging their sources of heating. A reduction in oil consumption has been the primary cause of this transition. There has also been a slight increase in the number of heat pumps in use. In total, heat pumps account for a small proportion of the heating of the properties in question. Heating costs account for a large proportion of operating expenses for property owners, in fact up to 40-50 percent of ongoing operating expenses. Reducing the cost of heating is very important, as this directly affects the property owners' bottom lines. Contractors are offering services to help property owners to optimise their energy-saving measures. The price of district heating, where this is available, is being used as a basis. This is why the structure of the price of district heating affects what measures are implemented. In price constructions with too high a flexible element, there is plenty of incentive to make savings on energy. District heating suppliers' coverage of set costs is reduced once the measures to ensure savings have been implemented, and so they have to increase their prices retrospectively. In price constructions with a high set element, there is little incentive to make savings, with a subsequent increase in demand for heating in extreme cases. District heating suppliers can be forced to make investments in both generation and

Radiation effects on heat transfer in heat exchangers, (2)

International Nuclear Information System (INIS)

Mori, Yasuo; Watanabe, Kenji; Taira, Tatsuji.

1980-01-01

In a high temperature gas-cooled reactor system, in which the working fluid exchanges heat at high temperature near 1000 deg C, the heat transfer acceleration by positively utilizing the radiation heat transfer between solid surfaces should be considered. This paper reports on the results of experiment and analysis for the effects of radiant heat on the heat transfer performance at elevated temperature by applying the heat transfer-accelerating method using radiators to the heat exchanger with tube bundle composed of two channels of heating and heated sides. As the test heat exchangers, a parallel counter flow exchanger and the cross flow exchanger simulating helical tubes were employed, and the results studied on the characteristics of each heat exchanger are described. The plates placed in parallel to flow in every space of the tube bundle arranged in a matrix were used as the heat transfer accelerator. The effects of acceleration with the plates were the increase of heat transmission from 12 to 24% and 12 to 38% in the parallel flow and cross flow heat exchangers, respectively. Also, it was clarified that the theoretical analysis, in which it was assumed that the region within pitch S and two radiator plates, with a heat-transferring tube placed at the center, is the minimum domain for calculation, and that the heat exchange by radiation occurs only between the domain and the adjacent domains, can estimate the heat transfer-accelerating effect and the temperature distribution in a heat exchanger with sufficient accuracy. (Wakatsuki, Y.)

Half-Space Temperature Field with a Movable Thermally Thin-Coated Boundary Under External Heat Flux

Directory of Open Access Journals (Sweden)

P. A. Vlasov

2014-01-01

Full Text Available In engineering practice analytical methods of the mathematical theory of heat conduction hold a special place. This is due to many reasons, in particular, because of the fact that the solutions of the relevant problems represented in analytically closed form, can be used not only for a parametric analysis of the studied temperature field and to explore the specific features of its formation, but also to test the developed computational algorithms, which are aimed at solving real-world application heat and mass transfer problems. Difficulties arising when using the analytical mathematical theory methods of heat conduction in practice are well known. Also they are significantly exacerbated if the boundaries of the system under study are movable, even in the simplest case, when the law of motion is known.The main goal of the conducted research is to have an analytically closed-form problem solution for finding the orthotropic half-space temperature field, a boundary of which has thermally thin coating exposed to extremely concentrated stationary external heat flux and uniformly moves parallel to itself.The assumption that the covering of the boundary is thermally thin, allowed to realize the idea of \\concentrated capacity", that is to accept the hypothesis that the mean-thickness coating temperature is equal to the temperature of its boundaries. This assumption allowed us to reduce the problem under consideration to a mixed problem for a parabolic equation with a specific boundary condition.The Hankel integral transform of zero order with respect to the radial variable and the Laplace transform with respect to the temporal variable were used to solve the reduced problem. These techniques have allowed us to submit the required solution as an iterated integral.

Heat transfer characteristics of a helical heat exchanger

International Nuclear Information System (INIS)

San, Jung-Yang; Hsu, Chih-Hsiang; Chen, Shih-Hao

2012-01-01

Heat transfer performance of a helical heat exchanger was investigated. The heat exchanger is composed of a helical tube with rectangular cross section and two cover plates. The ε–Ntu relation of the heat exchanger was obtained using a numerical method. In the analysis, the flow in the tube (helical flow) was considered to be mixed and the flow outside the tube (radial flow) was unmixed. In the experiment, the Darcy friction factor (f) and convective heat transfer coefficient (h) of the radial flow were measured. The radial flow was air and the helical flow was water. Four different channel spacing (0.5, 0.8, 1.2 and 1.6 mm) were individually considered. The Reynolds numbers were in the range 307–2547. Two correlations, one for the Darcy friction factor and the other for the Nusselt number, were proposed. - Highlights: ► We analyze the heat transfer characteristics of a helical heat exchanger and examine the effectiveness–Ntu relation. ► Increasing number of turns of the heat exchanger would slightly increase the effectiveness. ► There is an optimum Ntu value corresponding to a maximum effectiveness. ► We measure the Darcy friction factor and Nusselt number of the radial flow and examine the correlations.

Decreasing of energy consumption for space heating in existing residential buildings

International Nuclear Information System (INIS)

Stamov, S.; Zlateva, M.; Gechkov, N.

2000-01-01

An analysis is for the technical possibilities for reducing the energy consumption in existing buildings by means of the heat control and measurement. The basic performances of the heat capacity control methods, of the hierarchy structure of the control and of the heat measurement technologies are presented. This paper also presents the results from the long-term investigation of energy consumption for heating. The results area consist of three typical and uniform buildings in the city of Kazanlak (Bulgaria). The outcome of the investigation provides a valuable basis for future decisions to be made concerning reconstruction of heating installations and enables the results to be transferred. (Authors)

General-purpose heat source project and space nuclear safety and fuels program. Progress reportt, January 1980

International Nuclear Information System (INIS)

Maraman, W.J.

1980-04-01

This formal monthly report covers the studies related to the use of 238 PuO 2 in radioisotopic power systems carried out for the Advanced Nuclear Systems and Projects Division of the Los Alamos Scientific Laboratory. The two programs involved are the general-purpose heat source development and space nuclear safety and fuels. Most of the studies discussed here are of a continuing nature. Results and conclusions described may change as the work continues. Published reference to the results cited in this report should not be made without the explicit permission of the person in charge of the work

Rational energy use and the gas utility. An economic analysis of energy efficiency strategies on the space heating market

International Nuclear Information System (INIS)

Helle, C.

1994-01-01

Apart from the political authorities, also the supply utilities may contribute to a more widespread rational energy use. This investigtion focuses on the gas utilities, which have a wide range of options for higher energy efficiency, especially on the space heating market. These options are analyzed in the framework of the process of company straategy planning. Particular interest is taken in the product-political strategy of forward integration. (orig.) [de

Enhancement of combined heat and mass transfer in a vertical-tube heat and mass exchanger

International Nuclear Information System (INIS)

Webb, R.L.; Perez-Blanco, H.

1986-01-01

This paper studies enhancement of heat and mass transfer between a countercurrent, gravity-drained water film and air flowing in a vertical tube. The enhancement technique employed is spaced, transverse wires placed in the air boundary layer, near the air--water interface. Heat transfer correlations for turbulent, single-phase heat transfer in pipes having wall-attached spaced ribs are used to select the preferred wire diameter, and to predict the gas phase heat and mass transfer coefficients. Tests were run with two different radial placements of the rib roughness: (1) at the free surface of the liquid film, and (2) the base of the roughness displaced 0.51 mm into the air flow. The authors hypothesize that the best heat/mass transfer and friction performance will be obtained with the roughness at the surface of the water film. Experiments conducted with both roughness placements show that the authors' hypothesis is correct. The measured heat/mass transfer enhancement agreed very closely with the predicted values. A unique feature of the enhancement concept is that it does not require surface wetting of the enhancement device to provide enhancement

Performance of a Solar Heating System with Photovoltaic Thermal Hybrid Collectors and Heat Pump

DEFF Research Database (Denmark)

Dannemand, Mark; Furbo, Simon; Perers, Bengt

2017-01-01

. When the solar collectors are unable to supply the heat demand an auxiliary heat source is used. Heat pumps can generate this heat. Liquid/water heat pumps have better performance than air/water heat pumps in cold climates but requires installation of a tubing system for the cold side of the heat pump....... The tubes are typically placed in the ground, requires a significant land area and increase the installation cost. A new system design of a solar heating system with two storage tanks and a liquid/water heat pump is presented. The system consists of PVT collectors that generate both heat and electricity......The energy consumption in buildings accounts for a large part of the World’s CO2 emissions. Much energy is used for appliances, domestic hot water preparation and space heating. In solar heating systems, heat is captured by solar collectors when the sun is shining and used for heating purposes...

Analysis of fluid flow and heat transfer in a double pipe heat exchanger with porous structures

International Nuclear Information System (INIS)

Targui, N.; Kahalerras, H.

2008-01-01

A numerical study of flow and heat transfer characteristics is made in a double pipe heat exchanger with porous structures inserted in the annular gap in two configurations: on the inner cylinder (A) and on both the cylinders in a staggered fashion (B). The flow field in the porous regions is modelled by the Darcy-Brinkman-Forchheimer model and the finite volume method is used to solve the governing equations. The effects of several parameters such as Darcy number, porous structures thickness and spacing and thermal conductivity ratio are considered in order to look for the most appropriate properties of the porous structures that allow optimal heat transfer enhancement. It is found that the highest heat transfer rates are obtained when the porous structures are attached in configuration B especially at small spacing and high thicknesses

Fuel savings with conventional hot water space heating systems by incorporating a natural gas powered heat pump. Preliminary project: Development of heat pump technology

Science.gov (United States)

Vanheyden, L.; Evertz, E.

1980-12-01

Compression type air/water heat pumps were developed for domestic heating systems rated at 20 to 150 kW. The heat pump is driven either by a reciprocating piston or rotary piston engine modified to operate on natural gas. Particular features of natural gas engines as prime movers, such as waste heat recovery and variable speed, are stressed. Two systems suitable for heat pump operation were selected from among five different mass produced car engines and were modified to incorporate reciprocating piston compressor pairs. The refrigerants used are R 12 and R 22. Test rig data transferred to field conditions show that the fuel consumption of conventional boilers can be reduced by 50% and more by the installation of engine driven heat pumps. Pilot heat pumps based on a 1,600 cc reciprocating piston engine were built for heating four two-family houses. Pilot pump operation confirms test rig findings. The service life of rotary piston and reciprocating piston engines was investigated. The tests reveal characteristic curves for reciprocating piston engines and include exhaust composition measurements.

The adjoint space in heat transport theory

International Nuclear Information System (INIS)

Dam, H. van; Hoogenboom, J.E.

1980-01-01

The mathematical concept of adjoint operators is applied to the heat transport equation and an adjoint equation is defined with a detector function as source term. The physical meaning of the solutions for the latter equation is outlined together with an application in the field of perturbation analysis. (author)

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

Directory of Open Access Journals (Sweden)

Ірина Геннадіївна Шитікова

2016-11-01

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

Compact heat exchanger for power plants

International Nuclear Information System (INIS)

Kinnunen, L.

2001-01-01

Vahterus Oy, located at Kalanti, has manufactured heat exchangers since the beginning of 1990s. About 90% of the equipment produced are exported. In the PSHE (Plate and Shell) solution of the Vahterus heat exchanger the heat is transferred by round plated welded to form a compact package, which is assembled into a cylindrical steel casing. The heat exchanger contains no gaskets or soldered joints, which eliminates the leak risks. Traditional heat exchanges are usually operated at higher temperatures and pressures, but the heat transfer capacities of them are lower. Plate heat exchangers, on the other hand, are efficient, but the application range of them is narrow. Additionally, the rubber gasket of the heat exchange plates, sealing the joints of the heat exchanging plates, does not stand high pressures or temperatures, or corroding fluids. The new welded plate heat exchanger combine the pressure and temperature resistance of tube heat exchangers and the high heat exchange capacity of plate heat exchangers. The new corrosion resisting heat exchanger can be applied for especially hard conditions. The operating temperature range of the PSHE heat exchanger is - 200 - 900 deg C. The pressure resistance is as high as 100 bar. The space requirement of PSHE is only one tenth of the space requirement of traditional tube heat exchangers. Adjusting the number of heat exchanging plates can change the capacity of the heat exchanger. Power range of the heat exchanger can be as high as 80 MW. Due to the corrosion preventive construction and the small dimension the PSHE heat exchanger can be applied for refrigerators using ammonia as refrigerant. These kinds of new Vahterus heat exchangers are in use in 60 countries in more than 2000 refrigerators

A novel design method for ground source heat pump

Directory of Open Access Journals (Sweden)

Dong Xing-Jie

2014-01-01

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

In-Space Manufacture of Storable Propellants

Data.gov (United States)

National Aeronautics and Space Administration — Many deep-space, missions, especially those that return material or crews to near-Earth space, are severely limited by the need to carry propellants and heat shields...

Development of space heating and domestic hot water systems with compact thermal energy storage. Compact thermal energy storage: Material development for System Integration

NARCIS (Netherlands)

Davidson, J.H.; Quinnell, J.; Burch, J.; Zondag, H.A.; Boer, R. de; Finck, C.J.; Cuypers, R.; Cabeza, L.F.; Heinz, A.; Jahnig, D.; Furbo, S.; Bertsch, F.

2013-01-01

Long-term, compact thermal energy storage (TES) is essential to the development of cost-effective solar and passive building-integrated space heating systems and may enhance the annual technical and economic performance of solar domestic hot water (DHW) systems. Systems should provide high energy

Fluid-cooled heat sink for use in cooling various devices

Science.gov (United States)

Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth; Narumanchi, Sreekant

2017-09-12

The disclosure provides a fluid-cooled heat sink having a heat transfer base, a shroud, and a plurality of heat transfer fins in thermal communication with the heat transfer base and the shroud, where the heat transfer base, heat transfer fins, and the shroud form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop of the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.

Electric space heating scheduling for real-time explicit power control in active distribution networks

DEFF Research Database (Denmark)

Costanzo, Giuseppe Tommaso; Bernstein, Andrey; Chamorro, Lorenzo Reyes

2015-01-01

This paper presents a systematic approach for abstracting the flexibility of a building space heating system and using it within a composable framework for real-time explicit power control of microgrids and, more in general, active distribution networks. In particular, the proposed approach...... is developed within the context of a previously defined microgrid control framework, called COMMELEC, conceived for the explicit and real-time control of these specific networks. The designed control algorithm is totally independent from the need of a building model and allows exploiting the intrinsic thermal...... inertia for real-time control. The paper first discusses the general approach, then it proves its validity via dedicated simulations performed on specific case study composed by the CIGRE LV microgrid benchmark proposed by the Cigré TF C6.04.02....

A model predictive control strategy for the space heating of a smart building including cogeneration of a fuel cell-electrolyzer system

DEFF Research Database (Denmark)

Sossan, Fabrizio; Bindner, Henrik W.; Madsen, Henrik

2014-01-01

The objective of this paper is to analyze the value of energy replacement in the context of demand response. Energy replacement is dened as the possibility of the consumer to choose the most convenient source for providing space heating to a smart building according to a dynamic electricity price....... In the proposed setup, heat is provided by conventional electric radiators and a combined heat and power generation system, composed by a fuel cell and an electrolyzer. The energy replacement strategy is formulated using model predictive control and mathematical models of the components involved. Simulations show...... that the predictive energy replacement strategy reduces the operating costs of the system and is able to provide a larger amount of regulating power to the grid. In the paper, we also develop a novel dynamic model of a PEM fuel cell suitable for micro-grid applications. The model is realized applying a grey...

14 CFR 25.833 - Combustion heating systems.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Combustion heating systems. 25.833 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.833 Combustion heating systems. Combustion heaters must be approved. [Amdt. 25-72, 55 FR 29783, July 20, 1990...

14 CFR 23.1326 - Pitot heat indication systems.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Pitot heat indication systems. 23.1326... Instruments: Installation § 23.1326 Pitot heat indication systems. If a flight instrument pitot heating system... provided to indicate to the flight crew when that pitot heating system is not operating. The indication...

14 CFR 125.206 - Pitot heat indication systems.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Pitot heat indication systems. 125.206... Equipment Requirements § 125.206 Pitot heat indication systems. (a) Except as provided in paragraph (b) of... flight instrument pitot heating system unless the airplane is equipped with an operable pitot heat...

14 CFR 25.1326 - Pitot heat indication systems.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Pitot heat indication systems. 25.1326....1326 Pitot heat indication systems. If a flight instrument pitot heating system is installed, an indication system must be provided to indicate to the flight crew when that pitot heating system is not...

The Swiss heating reactor (SHR) for district heating of small communities

International Nuclear Information System (INIS)

Burgsmueller, P.; Jacobi, A.Jr.; Jaeger, J.F.; Klaentschi, M.J.; Seifritz, W.; Vuillemier, F.; Wegmann, F.

1987-01-01

With fossil fuel running out in a foreseeable future, it is essential to develop substitution strategies. Some 40-50 % of the heat demand in industrial countries is below 120 degrees C, for space heating and warm water production, causing a corresponding fraction of air pollution by SO 2 and to a lesser extent NO x if fossil fuels are used. Yet, contemporary LWR technology makes it feasible to supply a district heating network without basically new reactor development. Units in the power range 10-50 MW are most suitable for Switzerland, both in respect of network size and of the democratic decision making structure. A small BWR for heating purpose is being developed by parts of the Swiss Industry and the Swiss Federal Institute for Reactor Research (EIR). The economic target of 100-120 SFr/MWh heat at the consumer's seems achievable. (author)

Earliest Deadline Control of a Group of Heat Pumps with a Single Energy Source

NARCIS (Netherlands)

Fink, J.; van Leeuwen, Richard Pieter

2016-01-01

In this paper, we develop and investigate the optimal control of a group of 104 heat pumps and a central Combined Heat and Power unit (CHP). The heat pumps supply space heating and domestic hot water to households. Each house has a buffer for domestic hot water and a floor heating system for space

14 CFR 135.158 - Pitot heat indication systems.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Pitot heat indication systems. 135.158... Equipment § 135.158 Pitot heat indication systems. (a) Except as provided in paragraph (b) of this section... instrument pitot heating system unless the airplane is also equipped with an operable pitot heat indication...

Nuclear power plant with improved arrangements for the removal of post fission and emergency heating

International Nuclear Information System (INIS)

Buescher, E.; Vinzens, K.

1977-01-01

This is concerned with additional equipment for emergency heat removal in a sodium cooled reactor, which operates on failure of the post fission heat removal system. The space for pressure relieving spaces and concrete masses as heat sinks within the reactor cell is no longer required. In this nuclear power plant, a heat exchanger chain transmits heat and power: There is a first sodium circuit between pressure vessel and the first heat exchanger, a second one between the first and second heat excahngers, and a third (Steam) circuit with turbine, condenser and return pump. A fourth circuit connects the secondary side of the condenser with a cooling tower. There is a threee component heat excahgner in the primary circuit after the first heat exchanger, which is built around the first heat exchanger, and is sealed into an unloading space. This space is situated next to the reactor cell and is above the operating level of the sodium in the pressure vessel. It is connected to the cell by an upper duct, normally closed by a bursting disc, and by a lower duct. In the three comopnent heat exchanger, a liquid lead-bismuth eutectic mixture transmits the heat from sodium pipes to water pipes. In normal operation it is used for steam superheating or feedwater preheating. The three component heat exchanger bridges the first and second heat exchangers as an emergency heat exchanger. If in such a case the post fission heat removal has failed, the sodium evaporating in the pressure vessel flows into the unloading space and condenses on the ribs of the emergency heat exchanger. The post fission heat is fed by the water secondary medium directly into the tertiary circuit. The sodium condensate flows back from the unloading space via the lower duct into the reactor cell and maintains the emergency level there. (RW) 891 RW [de

Solar heating and cooling of buildings

Science.gov (United States)

Bourke, R. D.; Davis, E. S.

1975-01-01

Solar energy has been used for space heating and water heating for many years. A less common application, although technically feasible, is solar cooling. This paper describes the techniques employed in the heating and cooling of buildings, and in water heating. The potential for solar energy to displace conventional energy sources is discussed. Water heating for new apartments appears to have some features which could make it a place to begin the resurgence of solar energy applications in the United States. A project to investigate apartment solar water heating, currently in the pilot plant construction phase, is described.

Hybrid Heat Pipes for High Heat Flux Spacecraft Thermal Control, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Grooved aluminum/ammonia Constant Conductance Heat Pipes (CCHPs) are the standard for thermal control in zero-gravity. Unfortunately, they are limited in terms of...

Ventilation with heat recovery

DEFF Research Database (Denmark)

Tommerup, Henrik M.; Svendsen, Svend

2005-01-01

This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...

Champagne Heat Pump

Science.gov (United States)

Jones, Jack A.

2004-01-01

The term champagne heat pump denotes a developmental heat pump that exploits a cycle of absorption and desorption of carbon dioxide in an alcohol or other organic liquid. Whereas most heat pumps in common use in the United States are energized by mechanical compression, the champagne heat pump is energized by heating. The concept of heat pumps based on other absorption cycles energized by heat has been understood for years, but some of these heat pumps are outlawed in many areas because of the potential hazards posed by leakage of working fluids. For example, in the case of the water/ammonia cycle, there are potential hazards of toxicity and flammability. The organic-liquid/carbon dioxide absorption/desorption cycle of the champagne heat pump is similar to the water/ammonia cycle, but carbon dioxide is nontoxic and environmentally benign, and one can choose an alcohol or other organic liquid that is also relatively nontoxic and environmentally benign. Two candidate nonalcohol organic liquids are isobutyl acetate and amyl acetate. Although alcohols and many other organic liquids are flammable, they present little or no flammability hazard in the champagne heat pump because only the nonflammable carbon dioxide component of the refrigerant mixture is circulated to the evaporator and condenser heat exchangers, which are the only components of the heat pump in direct contact with air in habitable spaces.

Solar space heating for the Visitors Center, Stephens College, Columbia, Missouri

Science.gov (United States)

1980-01-01

The solar energy system located at the Visitors' Center on the Stephens College Campus, Columbia, Missouri is discussed. The system is installed in a four-story, 15,000 square foot building. The solar energy system is an integral design of the building and utilizes 176 hydronic flat plate collectors which use a 50 percent water ethylene blycol solution and water-to-water heat exchanger. Solar heated water is stored in a 5,000 gallon water storage tank located in the basement equipment room. A natural gas fired hot water boiler supplies hot water when the solar energy heat supply fails to meet the demand. The designed solar contribution is 71 percent of the heating load.

Heat exchanger

International Nuclear Information System (INIS)

Leigh, D.G.

1976-01-01

The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

An integrated heat pipe-thermal storage design for a solar receiver

Science.gov (United States)

Keddy, E.; Sena, J. T.; Woloshun, K.; Merrigan, M. A.; Heidenreich, G.

Light-weight heat pipe wall elements that incorporate a thermal storage subassembly within the vapor space are being developed as part of the Organic Rankine Cycle Solar Dynamic Power System (ORC-SDPS) receiver for the Space Station application. The operating temperature of the heat pipe elements is in the 770 to 810 K range with a design power throughput of 4.8 kW per pipe. The total heat pipe length is 1.9 M. The Rankine cycle boiler heat transfer surfaces are positioned within the heat pipe vapor space, providing a relatively constant temperature input to the vaporizer. The heat pipe design employs axial arteries and distribution wicked thermal storage units with potassium as the working fluid. Performance predictions for this configuration have been conducted and the design characterized as a function of artery geometry, distribution wick thickness, porosity, pore size, and permeability.

Prediction of temperature variation in a rotating spacecraft in space environment

International Nuclear Information System (INIS)

Gadalla, Mohamed A.

2005-01-01

This paper presents a closed-form prediction model for the temperature distribution of a thick-walled cylindrical space vehicle subjected to solar heating in deep space. The model is based on the coupling between dynamics and solar radiation. Since solar radiation is, in general, incident from a fixed direction, one side of the space vehicle will be shone bright, and the other side dark. Thus the space astronauts, instruments, and cryogenic-fuel tanks are gaining heat on the bright side and losing heat from the dark side. This radiative heat gain and loss become equally significant as the conductive heat transfer through the interior of the space vehicle. Thermal analysis is carried out to predict the effect of the spinning speed and angular position on the temperature variation and gradients attained by speed vehicles outside the Earth's atmosphere. This analysis is based on the non-linearity of the radiative heat dissipation, the significant conductive heat transfer role, and combined boundary conditions that involve the temperature and angular position of the vehicle. An exact analytical solution is obtained inspite of the non-linearity and non-homogeneity in the boundary conditions. The results indicate that the temperature distribution on the outer surface of the space vehicle is nearly independent of the angular position; at sub-cylindrical surface, this independence is achieved at low angular velocity

The exploitation of biomass for building space heating in Greece: Energy, environmental and economic considerations

International Nuclear Information System (INIS)

Michopoulos, A.; Skoulou, V.; Voulgari, V.; Tsikaloudaki, A.; Kyriakis, N.A.

2014-01-01

Highlights: • The oil substitution with biomass residues for heating buildings is examined. • Primary energy consumption from biomass results increased by 3–4% as compared to diesel oil. • CO 2 and SO 2 emissions are significantly higher with biomass than with diesel oil. • The examined substitution is economically attractive for the final consumers. - Abstract: The exploitation of forest and agricultural biomass residues for energy production may offer significant advantages to the energy policy of the relevant country, but it strongly depends on a number of financial, technological and political factors. The work in hand focuses on the investigation of the energy, environmental and financial benefits, resulting from the exploitation of forest and agricultural biomass residues, fully substituting the conventional fuel (diesel oil) for building space heating in Greece. For this investigation, the energy needs of a representative building are determined using the EnergyPlus software, assuming that the building is located across the various climate zones of Greece. Based on the resulting thermal energy needs, the primary energy consumption and the corresponding emissions are determined, while an elementary fiscal analysis is also performed. The results show that significant financial benefits for the end-user are associated with the substitution examined, even though increased emissions and primary energy consumption have been derived

Residential space heating with wood burning stoves. Energy efficiency and indoor climate; Boligopvarmning ved braendefyring. Energieffektivitet og indeklima

Energy Technology Data Exchange (ETDEWEB)

Jensen, Ole Michael; Afshari, A.; Bergsoee, N.C.; Carvalho, R. [Miljoestyrelsen, Copenhagen (Denmark); Aalborg Univ.. Statens Byggeforskningsinstitut, Aalborg (Denmark))

2012-11-01

Two issues turn up concerning how to use wood-burning stoves in modern homes. The first is whether wood-burning stoves in future may still act as a genuine heat source, given that new and refurbished single-family houses retain the heat much better than older ones and therefore need less and less energy for space heating. The second issue is whether it will still be possible to use wood-burning stoves in modern houses where the air exchange is controlled by mechanical ventilation or possibly heat recovery. It is a question whether firing techniques can be developed that will work in airtight houses with mechanical ventilation and negative pressure, so that harmful particle emissions can be avoided. To illustrate the first issue, a field study was designed to look carefully at seven modern wood-burning stoves that were set up in six new houses and one older house and investigated, both in terms of firing and heat release. As a background for this part of the study, a heat balance calculation was made for each house. The question is, whether wood-burning stoves will also in the future have a role to play as a heating source. Modern houses grow ever tighter and only need to be supplied with a small quantity of heat. The new Danish Buildings Requirement, 2010 has resulted in a further reduction of 25 % of the energy demand, including the energy supply for heating. However, the new requirements imply that the heating season eventually become so short that a traditional central heating installation becomes superfluous. This means that by using the small amounts of wood cut in gardens and hedgerows of the neighbourhood, a wood-burning stove will, in principle, cover the heating demand. Therefore, the question is rather whether a wood-burning stove is manufactured that can successfully be adapted to new houses. As a consequence of this development, future stoves must be further scaled down in order to meet the heating demand of a modern low-energy house and the stoves must

Energy efficient heating and ventilation of large halls

CERN Document Server

Hojer, Ondrej; Kabele, Karel; Kotrbaty, Miroslav; Sommer, Klaus; Petras, Dusan

2011-01-01

This guidebook is focused on modern methods for design, control and operation of energy efficient heating systems in large spaces and industrial halls. The book deals with thermal comfort, light and dark gas radiant heaters, panel radiant heating, floor heating and industrial air heating systems. Various heating systems are illustrated with case studies. Design principles, methods and modeling tools are presented for various systems.

Three story residence with solar heat--Manchester, New Hampshire

Science.gov (United States)

1981-01-01

When heat lost through ducts is counted for accurate performance assessment, solar energy supplied 56 percent of building's space heating load. Average outdoor temperature was 53 degrees F; average indoor temperature was 69 degrees F. System operating modes included heating from solar collectors, storing heat, heating from storage, auxiliary heating with oil fired furnace, summer venting, and hot water preheating.

Geothermal Direct Heat Application Potential

Energy Technology Data Exchange (ETDEWEB)

Lienau, Paul J

1989-01-01

The geothermal direct-use industry growth trends, potential, needs, and how they can be met, are addressed. Recent investigations about the current status of the industry and the identification of institutional and technical needs provide the basis on which this paper is presented. Initial drilling risk is the major obstacle to direct-use development. The applications presented include space and district heating projects, heat pumps (heating and cooling), industrial processes, resorts and pools, aquaculture and agriculture.

Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003

International Nuclear Information System (INIS)

Hadorn, J.-C.; Renaud, P.

2003-01-01

In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD+D projects

Modelling and multi-scenario analysis for electric heat tracing system combined with low temperature district heating for domestic hot water supply

DEFF Research Database (Denmark)

Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

2016-01-01

Low temperature district heating (LTDH) is a cost-efficient way of supplying space heating and domestic hot water (DHW) for buildings in urban areas. However, there is concern that the potential hygiene problems (Legionella) might occur if LTDH is implemented, especially for large buildings...... performance on heat loss saving, and it also gave benefits to district heating network by sharing part of the heating load....

ZrH reactor lattice spacing (heat transfer considerations)

International Nuclear Information System (INIS)

Felten, L.D.

1970-01-01

Temperature calculations for a 295 element ZrH reactor at fuel element spacings from 0.010'' to 0.065'' showed a very small dependence of reactor temperature on element spacing. It was found that one variation in coolant channel area (2 zones) was sufficient to satisfactorily shape the radial flow profile for the core. (U.S.)

Distribution of heating costs in multi-story apartment buildings

DEFF Research Database (Denmark)

Rose, Jørgen; Kragh, Jesper

2017-01-01

Under current rules in the Danish Meter Order at least 40% of the total heating costs in multi-story blocks of flats should be distributed by metering the consumption in individual apartments. This fixed share is the result of a previous study that showed that 40% of the total heating costs were...... used for space heating, 35% for production and heat loss associated with hot water consumption and finally 25% of heat losses in the heating system. It is interesting to investigate whether this distribution remains representative in both existing buildings, where older buildings still dominate......, as in newer and future standard of blocks of flats. Intuitively, we would like to settle 100% of the costs attributable to space heating, by individual meters. Thereby, tenants will pay for their own consumption which encourages energy savings. This is an excellent method for electricity, gas and water...

Solar Heating and Cooling of Buildings (Phase O). Volume 1: Executive Summary.

Science.gov (United States)

TRW Systems Group, Redondo Beach, CA.

The purpose of this study was to establish the technical and economic feasibility of using solar energy for the heating and cooling of buildings. Five selected building types in 14 selected cities were used to determine loads for space heating, space cooling and dehumidification, and domestic service hot water heating. Relying on existing and…

Position paper -- Waste storage tank heat removal

International Nuclear Information System (INIS)

Stine, M.D.

1995-01-01

The purpose of this paper is to develop and document a position on the heat removal system to be used on the waste storage tanks currently being designed for the Multi-Function Waste Tank Facility (MWTF), project W-236A. The current preliminary design for the waste storage primary tank heat removal system consists of the following subsystems: (1) a once-through dome space ventilation system; (2) a recirculation dome space ventilation system; and (3) an annulus ventilation system. Recently completed and ongoing studies have evaluated alternative heat removal systems in an attempt to reduce system costs and to optimize heat removal capabilities. In addition, a thermal/heat transfer analysis is being performed that will provide assurance that the heat removal systems selected will be capable of removing the total primary tank design heat load of 1.25 MBtu/hr at an allowable operating temperature of 190 F. Although 200 F is the design temperature limit, 190 F has been selected as the maximum allowable operating temperature limit based on instrumentation sensitivity, instrumentation location sensitivity, and other factors. Seven options are discussed and recommendations are made

Thermo-Acoustic Convertor for Space Power, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In Phase Sunpower looked at Thermoacoustic Stirling Heat Engines (TASHEs). These ranged from a TASHE which was sized for the heat from a single General Purpose Heat...

Phase Change Material (PCM) Heat Exchanger Development

Data.gov (United States)

National Aeronautics and Space Administration — The primary focus of the project is to provide future space vehicles a reliable form of long duration supplemental heat rejection (SHREDs). SHREDs allow a vehicle to...

An analysis of geothermal heating and engineering cost in Tianjin, China

International Nuclear Information System (INIS)

Wang, W.

1990-01-01

Tianjin is a region with fairly rich low-temperature geothermal resources. Its climate and soaring price of raw coals have made geo heating in Tianjin develop rapidly over the past 5 years. The types of heating systems fall into 3 categories and the primary factors for using temperature drop are 5. According to economical analysis, the optimal discharge temperature in the space heating is about 43 degrees C and the minimum discharge temperature 35 degrees C approximately. This paper reports that an analysis of a typical engineering costs involved shows that the advantages of geo space heating are not notable when compared with burning coals. However, to reduce air pollution, the state and general public are ready to support the development of such geothermal wells as deep as 3,000 m for space heating irrespective of their sole engineering costs

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.

Optimizing a Small Ammonia Heat Pump with Accumulator Tank for Space and Hot Tap Water Heating

OpenAIRE

Lalovs, Arturs

2015-01-01

The heat pump market offers a wide variety of different residential heat pumps where most of them utilize refrigerant R-410A which has high global warming potential. Considering the fact that global policy starts to focus on issues related to energy efficiency and harmful impact to the environment, it is necessary to investigate over new refrigerants. As an alternative solution is to utilize natural refrigerants, such as ammonia, which has almost zero glob...

Forced convection heat transfer correlation for finned plates in a duct

International Nuclear Information System (INIS)

Chae, Myeong-Seon; Moon, Je-Young; Chung, Bum-Jin

2014-01-01

Forced convection heat transfer experiments were conducted for plate-fin in a duct using various fin spacing, fin height, duct width, Reynolds number for Prandtl numbers 2,014. Based upon analogy concept, mass transfer rate were measured instead of heat transfer rates. The heat transfer rates were enhanced with the increase of fin height and decrease of fin spacing as they increase the heat transfer area. Meanwhile, heat transfer rates were impaired with the increase of the duct width as the bypass flows increased to tip clearance region. Forced convection heat transfer correlations were developed for laminar and turbulent flow conditions and for narrow and wide ducts. The work draws attention to the tip clearance on the heat transfer of the finned plate in a duct. (author)

Subcooled flow boiling heat transfer of ethanol aqueous solutions in vertical annulus space

Directory of Open Access Journals (Sweden)

Sarafraz M.M.

2012-01-01

Full Text Available The subcooled flow boiling heat-transfer characteristics of water and ethanol solutions in a vertical annulus have been investigated up to heat flux 132kW/m2. The variations in the effects of heat flux and fluid velocity, and concentration of ethanol on the observed heat-transfer coefficients over a range of ethanol concentrations implied an enhanced contribution of nucleate boiling heat transfer in flow boiling, where both forced convection and nucleate boiling heat transfer occurred. Increasing the ethanol concentration led to a significant deterioration in the observed heat-transfer coefficient because of a mixture effect, that resulted in a local rise in the saturation temperature of ethanol/water solution at the vapor-liquid interface. The reduction in the heat-transfer coefficient with increasing ethanol concentration is also attributed to changes in the fluid properties (for example, viscosity and heat capacity of tested solutions with different ethanol content. The experimental data were compared with some well-established existing correlations. Results of comparisons indicate existing correlations are unable to obtain the acceptable values. Therefore a modified correlation based on Gnielinski correlation has been proposed that predicts the heat transfer coefficient for ethanol/water solution with uncertainty about 8% that is the least in comparison to other well-known existing correlations.

Performance investigations of liquid-metal heat pipes for space and terrestrial applications

International Nuclear Information System (INIS)

Kemme, J.E.; Keddy, E.S.; Phillips, J.R.

1978-01-01

The high heat transfer capacity of liquid-metal heat pipes is demonstrated in performance tests with mercury, potassium, sodium, and lithium working fluids and wick structures which serve to minimize liquid pressure losses and vapor/liquid interactions. Appropriate wicks for horizontal and vertical operation are described. It is shown that heat-transfer with these wicks is limited by vapor flow effects. Examples are given of particular effects associated with a long adiabatic section between evaporator and condenser and with a heat source of uniform temperature as opposed to a source of uniform power

New operational spaces for the electron cyclotron resonance heating at ASDEX upgrade

International Nuclear Information System (INIS)

Hoehnle, Hendrik Sebastian

2012-01-01

In this thesis, new electron cyclotron resonance heating (ECRH) scenarios were developed for an extension of the operational space at the tokamak ASDEX Upgrade in view of ITER compatibility. In the last years, the first wall material at ASDEX Upgrade was changed from graphite to tungsten, and the ECRH is needed to control the tungsten concentration in the plasma core. But, in ITER-like plasma discharges at ASDEX Upgrade, the usage of the ECRH in the typically used second harmonic extraordinary polarised mode (X2 mode) is limited. In these ITER-scenarios a small safety factor should be achieved, which implements an increase of the plasma current at ASDEX Upgrade. A higher plasma current and a high confinement lead to a raised density and for the ITER scenario to an electron density above the cutoff of the X2 mode at ASDEX Upgrade. Therefore, the X2 mode is reflected at the cutoff layer and cannot be used for central heating and the control of the tungsten concentration. One possibility to overcome this problem is to apply the third harmonic mode at reduced magnetic field. Here the cutoff is increased by 33% due to the dependence on the magnetic field. However, at the reachable plasma parameters at the reduced field the absorption of the X3 mode is incomplete (60-70 %) and the shine-trough power can destroy microwave sensitive components in ASDEX Upgrade. To solve this problem the magnetic field has to be optimized. A slightly increased magnetic field from 1.7 T to 1.8 T moves the second harmonic resonance in the region of confined plasma with high temperatures and density, so that this resonance can act as beam dump. The deposition in the plasma core is still central enough for the tungsten control ability of the ECRH. The benefit of the beam dump was verified in experiments with two different magnetic fields (1.7 T and 1.8 T). In case of the higher magnetic field, the stray radiation was reduced; simultaneously the electron temperature was increased. In addition

Boiling heat transfer in a flat slot between heating surface and perforated plate

International Nuclear Information System (INIS)

Kirichenko, Yu.A.; Rusanov, K.V.; Tyurina, E.G.

1987-01-01

The results are presented of the experimental study of heat transfer and crisis at nitrogen boiling in a flat gap between the horizontal heating surface and perforated plate. The gap width is 1.0 to 5.6 mm, diameter of holes is 1.0 to 2.0 mm, their spacing being 3.0 to 12.0 mm. The geometrical parameters dependence of the heat transfer coefficient and crisis characteristics is invesigated, the experimental data are compared with the results reported by other authors and calculations by some well-known formulas. 12 refs.; 3 figs.; 4 tabs

Central model predictive control of a group of domestic heat pumps, case study for a small district

NARCIS (Netherlands)

van Leeuwen, Richard Pieter; Fink, J.; Smit, Gerardus Johannes Maria; Helfert, Markus; Krempels, Karl-Heinz; Donnellan, Brian; Klein, Cornel

2015-01-01

In this paper we investigate optimal control of a group of heat pumps. Each heat pump provides space heating and domestic hot water to a single household. Besides a heat pump, each house has a buffer for domestic hot water and a floor heating system for space heating. The paper describes models and

Forced heat convection in annular spaces; Convection forcee de la chaleur dans les espaces annulaires

Energy Technology Data Exchange (ETDEWEB)

Pelce, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1960-02-15

This report deals with the experimental study of forced heat convection in annular spaces through which flow of air is passing when a uniform heat flux is dissipated across the inner wall. These observations took place chiefly in the region where thermal equilibrium are not yet established. Amongst other things it became apparent that, both in the region where thermal equilibrium conditions are on the way to establishment and where they are already established, the following relationship held good: the longitudinal temperature gradient, either on the wall or in the fluid stream, is proportional to the heat flux dissipated q, and inversely proportional to the average flow rate V: dT/dx = B (q/V). From this result the next step is to express the variations of the local convection coefficient {alpha} (or of the Margoulis number M) in a relationship of the form: 1/M = {psi}(V) + F(x). If this relationship is compared with the classical empirical relationship {alpha} = KV{sup n} (where n is close to 0.8), the relationship: 1/M = {xi}V{sup 1-n} + F(x) is obtained ({xi} is a constant for a given annular space); from this it was possible to coordinate the whole set of experimental results. (author) [French] Il s'agit precisement de l'etude experimentale de la convection forcee de la chaleur dans des espaces annulaires parcourus par de l'air en ecoulement turbulent, lorsqu'on dissipe a travers la paroi interieure un flux de chaleur uniforme. Ces observations ont eu lieu principalement dans la region ou le regime thermique n'est pas encore etabli. Il est apparu, entre autre, qu'il existait, tant dans la region ou le regime thermique est en voie d'etablissement qu'en regime etabli, la relation suivante: le gradient longitudinal des temperatures, que ce soit sur la paroi ou dans l'ecoulement fluide, est proportionnel au flux de la chaleur dissipee q, et inversement proportionnel a la vitesse moyenne V de l'ecoulement: dT/dx = B (q/V). Ce resultat a pour consequence de traduire

Theoretical study of heat pump system using CO2/dimethylether as refrigerant

Directory of Open Access Journals (Sweden)

Fan Xiao-Wei

2013-01-01

Full Text Available Nowadays, HCFC22 is widely used in heat pump systems in China, which should be phased out in the future. Thus, eco-friendly mixture CO2/dimethylether is proposed to replace HCFC22. Compared with pure CO2 and pure dimethylether, the mixture can reduce the heat rejection pressure, and suppress the flammability and explosivity of pure dimethylether. According to the Chinese National Standards on heat pump water heater and space heating system, performances of the subcritical heat pump system are discussed and compared with those of the HCFC22 system. It can be concluded that CO2 /dimethylether mixture works efficiently as a refrigerant for heat pumps with a large heat-sink temperature rise. When mass fraction of dimethylether is increased, the heat rejection pressure is reduced. Under the nominal working condition, there is an optimal mixture mass fraction of 28/72 of CO2/dimethylether for water heater application under conventional condensation pressure, 3/97 for space heating application. For water heater application, both the heating coefficient of performance and volumetric heating capacity increase by 17.90% and 2.74%, respectively, compared with those of HCFC22 systems. For space heating application, the heating coefficient of performance increases by 8.44% while volumetric heating capacity decreases by 34.76%, compared with those of HCFC22 systems. As the superheat degree increases, both the heating coefficient of performance and volumetric heating capacity tend to decrease.

Air Circulation and Heat Exchange under Reduced Pressures

Science.gov (United States)

Rygalov, Vadim; Wheeler, Raymond; Dixon, Mike; Hillhouse, Len; Fowler, Philip

Low pressure atmospheres were suggested for Space Greenhouses (SG) design to minimize sys-tem construction and re-supply materials, as well as system manufacturing and deployment costs. But rarified atmospheres modify heat exchange mechanisms what finally leads to alter-ations in thermal control for low pressure closed environments. Under low atmospheric pressures (e.g., lower than 25 kPa compare to 101.3 kPa for normal Earth atmosphere), convection is becoming replaced by diffusion and rate of heat exchange reduces significantly. During a period from 2001 to 2009, a series of hypobaric experiments were conducted at Space Life Sciences Lab (SLSLab) NASA's Kennedy Space Center and the Department of Space Studies, University of North Dakota. Findings from these experiments showed: -air circulation rate decreases non-linearly with lowering of total atmospheric pressure; -heat exchange slows down with pressure decrease creating risk of thermal stress (elevated leaf tem-peratures) for plants in closed environments; -low pressure-induced thermal stress could be reduced by either lowering system temperature set point or increasing forced convection rates (circulation fan power) within certain limits; Air circulation is an important constituent of controlled environments and plays crucial role in material and heat exchange. Theoretical schematics and mathematical models are developed from a series of observations. These models can be used to establish optimal control algorithms for low pressure environments, such as a space greenhouse, as well as assist in fundamental design concept developments for these or similar habitable structures.

Applications of nuclear-powered thermoelectric generators in space

International Nuclear Information System (INIS)

Rowe, D.M.

1991-01-01

The source of electrical power which enables information to be transmitted from the space crafts Voyager 1 and 2 back to Earth after a time period of more than a decade and at a distance of more than a billion miles is known as an RTG (radioisotope thermoelectric generator). It utilises the Seebeck effect in producing electricity from heat. In essence it consists of a large number of semiconductor thermocouples connected electrically in series and thermally in parallel. A temperature difference is maintained across the thermocouples by providing a heat source, which in the case of an RTG is a radioactive isotope, and the heat sink is space. The combination of an energy-conversion system, free of moving parts and a long-life, high energy-density heat source, provides a supply of electrical power typically in the range of tens to hundred of watts and which operates reliably over extended periods of time. An electric power source, based upon thermoelectric conversion by which utilises a nuclear reactor as a heat source, has also been deployed in space and a 100-kW system is being developed to provide electrical power to a variety of commercial and military projects including SDI. Developments in thermoelectrics that have taken place in the western world during the past 30 years are primarily due to United States interest and involvement in the exploration of space. This paper reviews US applications of nuclear-powered thermoelectric generators in space. (author)

Field Demonstration of Ground-Source Integrated Heat Pump - Final Report

Energy Technology Data Exchange (ETDEWEB)

Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gehl, Anthony C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-01

Reducing energy consumption in buildings is key to reducing or limiting the negative environmental impacts from the building sector. According to the United States (U.S.) Energy Information Administration (EIA), in 2013, commercial buildings consumed 18.1 quads of primary energy, which was 18.6% of the total U.S. primary energy consumption. The primary energy consumption in the commercial sector is projected to increase by 2.8 quads from 2013 to 2040, the second largest increase after the industrial sector. Further space heating, space cooling, and ventilation (HVAC) services accounted for 31% of the energy consumption in commercial buildings. The technical objective of this project is to demonstrate the capability of the new GS-IHP system to reduce overall energy use for space heating, space cooling, and water heating by at least 45% vs. a conventional electric RTU and electric WH in a light commercial building application. This project supports the DOE-Building Technologies Office (BTO) goals of reducing HVAC energy use by 20% and water heating by 60% by 2030.

Geothermal heat pumps - Trends and comparisons

Energy Technology Data Exchange (ETDEWEB)

Lund, John W

1989-01-01

Heat pumps are used where geothermal water or ground temperatures are only slightly above normal, generally 50 to 90 deg. F. Conventional geothermal heating (and cooling) systems are not economically efficient at these temperatures. Heat pumps, at these temperatures, can provide space heating and cooling, and with a desuperheater, domestic hot water. Two basic heat pump systems are available, air-source and water- or ground-source. Water- and ground-coupled heat pumps, referred to as geothermal heat pumps (GHP), have several advantages over air-source heat pumps. These are: (1) they consume about 33% less annual energy, (2) they tap the earth or groundwater, a more stable energy source than air, (3) they do not require supplemental heat during extreme high or low outside temperatures, (4) they use less refrigerant (freon), and (5) they have a simpler design and consequently less maintenance.

The embodiment design of the heat rejection system for the portable life support system

Science.gov (United States)

Stuckwisch, Sue; Francois, Jason; Laughlin, Julia; Phillips, Lee; Carrion, Carlos A.

1994-01-01

The Portable Life Support System (PLSS) provides a suitable environment for the astronaut in the Extravehicular Mobility Unit (EMU), and the heat rejection system controls the thermal conditions in the space suit. The current PLSS sublimates water to the space environment; therefore, the system loses mass. Since additional supplies of fluid must be available on the Space Shuttle, NASA desires a closed heat rejecting system. This document presents the embodiment design for a radiative plate heat rejection system without mass transfer to the space environment. This project will transform the concept variant into a design complete with material selection, dimensions of the system, layouts of the heat rejection system, suggestions for manufacturing, and financial viability.

46 CFR 190.20-50 - Heating and cooling.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Heating and cooling. 190.20-50 Section 190.20-50... CONSTRUCTION AND ARRANGEMENT Accomodations for Officers, Crew, and Scientific Personnel § 190.20-50 Heating and... the space. (b) Radiators and other heating apparatus must be so placed and shielded, where necessary...

A Liquid-Liquid Thermoelectric Heat Exchanger as a Heat Pump for Testing Phase Change Material Heat Exchangers

Science.gov (United States)

Sheth, Rubik B.; Makinen, Janice; Le, Hung V.

2016-01-01

The primary objective of the Phase Change HX payload on the International Space Station (ISS) is to test and demonstrate the viability and performance of Phase Change Material Heat Exchangers (PCM HX). The system was required to pump a working fluid through a PCM HX to promote the phase change material to freeze and thaw as expected on Orion's Multipurpose Crew Vehicle. Due to limitations on ISS's Internal Thermal Control System, a heat pump was needed on the Phase Change HX payload to help with reducing the working fluid's temperature to below 0degC (32degF). This paper will review the design and development of a TEC based liquid-liquid heat exchanger as a way to vary to fluid temperature for the freeze and thaw phase of the PCM HX. Specifically, the paper will review the design of custom coldplates and sizing for the required heat removal of the HX.

Generalized heat-transport equations: parabolic and hyperbolic models

Science.gov (United States)

Rogolino, Patrizia; Kovács, Robert; Ván, Peter; Cimmelli, Vito Antonio

2018-03-01

We derive two different generalized heat-transport equations: the most general one, of the first order in time and second order in space, encompasses some well-known heat equations and describes the hyperbolic regime in the absence of nonlocal effects. Another, less general, of the second order in time and fourth order in space, is able to describe hyperbolic heat conduction also in the presence of nonlocal effects. We investigate the thermodynamic compatibility of both models by applying some generalizations of the classical Liu and Coleman-Noll procedures. In both cases, constitutive equations for the entropy and for the entropy flux are obtained. For the second model, we consider a heat-transport equation which includes nonlocal terms and study the resulting set of balance laws, proving that the corresponding thermal perturbations propagate with finite speed.

Performance characteristics of a combination solar photovoltaic heat engine energy converter

Science.gov (United States)

Chubb, Donald L.

1987-01-01

A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

Thermal control system. [removing waste heat from industrial process spacecraft

Science.gov (United States)

Hewitt, D. R. (Inventor)

1983-01-01

The temperature of an exothermic process plant carried aboard an Earth orbiting spacecraft is regulated using a number of curved radiator panels accurately positioned in a circular arrangement to form an open receptacle. A module containing the process is insertable into the receptacle. Heat exchangers having broad exterior surfaces extending axially above the circumference of the module fit within arcuate spacings between adjacent radiator panels. Banks of variable conductance heat pipes partially embedded within and thermally coupled to the radiator panels extend across the spacings and are thermally coupled to broad exterior surfaces of the heat exchangers by flanges. Temperature sensors monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes in inverse proportion to changes in the temperature of the process fluid.

Thermal energy storage with geothermal triplet for space heating and cooling

Science.gov (United States)

Bloemendal, Martin; Hartog, Niels

2017-04-01

Many governmental organizations and private companies have set high targets in avoiding CO2 emissions and reducing energy (Kamp, 2015; Ministry-of-Economic-affairs, 2016). ATES systems use groundwater wells to overcome the discrepancy in time between the availability of heat (during summer) and the demand for heat (during winter). Aquifer Thermal Energy Storage is an increasingly popular technique; currently over 2000 ATES systems are operational in the Netherlands (Graaf et al., 2016). High temperature ATES may help to improve performance of these conventional ATES systems. ATES systems use heat pumps to get the stored heat to the required temperature for heating of around 40-50°C and to produce the cold water for cooling in summer. These heat pumps need quite a lot of power to run; on average an ATES system produces 3-4 times less CO2 emission compared to conventional. Over 60% of those emission are accounted for by the heat pump (Dekker, 2016). This heat pump power consumption can be reduced by utilizing other sources of sustainable heat and cooling capacity for storage in the subsurface. At such operating temperatures the required storage temperatures do no longer match the return temperatures in the building systems. Therefore additional components and an additional well are required to increase the groundwater temperature in summer (e.g. solar collectors) and decrease it in winter (e.g. dry coolers). To prevent "pollution" of the warm and cold well return water from the building can be stored in a third well until weather conditions are suitable for producing the required storage temperature. Simulations and an economical evaluation show great potential for this type of aquifer thermal energy storage; economic performance is better than normal ATES while the emissions are reduce by a factor ten. At larger temperature differences, also the volume of groundwater required to pump around is much less, which causes an additional energy saving. Research now

Thermoacoustic power systems for space applications

International Nuclear Information System (INIS)

Backhaus, S.N.; Tward, E.; Pedach, M.

2001-01-01

Future NASA deep-space missions will require radioisotope-powered electric generators that are just as reliable as current RTGs, but more efficient and of higher specific power (W/kg). Thermoacoustic engines can convert high-temperature heat into acoustic, or PV, power without moving parts at 30% efficiency. Consisting of only tubes and a few heat exchangers, these engines are low mass and promise to be highly reliable. Coupling a thermoacoustic engine to a low-mass, highly reliable and efficient linear alternator will create a heat-driven electric generator suitable for deep-space applications. Data will be presented on the first tests of a demonstration thermoacoustic engine designed for the 100-Watt power range.

Free-piston Stirling engine system considerations for various space power applications

International Nuclear Information System (INIS)

Dochat, G.R.; Dhar, M.

1991-01-01

The U.S. Government is evaluating power requirements for future space applications. As power requirements increase solar or nuclear dynamic systems become increasingly attractive. Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (AC, DC, high or low voltage, and fixed or variable load). This paper will review potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. Currently free-piston Stirling engine technology for space power applications is being developed under contract with NASA-Lewis Research Center. This paper will also briefly outline the program and recent progress

Study on thermal comfort, air quality and energy savings using bioenergy via gasification/combustion for space heating of a broiler house

Energy Technology Data Exchange (ETDEWEB)

Silva, Jadir Nogueira da; Zanatta, Fabio Luiz; Tinoco, Ilda de Fatima F.; Martin, Samuel [Universidade Federal de Vicosa (DEA/UFV), MG (Brazil). Dept. de Engenharia Agricola], E-mail: jadir@ufv.br; Scholz, Volkhard [Leibniz Institut fuer Agrartechnik- ATB, Potsdam (Germany)

2008-07-01

The annual production of chicken meat is increasing throughout the world and Brazil is the world leader regarding exportation, a prediction indicates about 2.7 millions tons to be exported in 2007. A key to this performance is the low production costs, however, the costs of space heating necessary during the first 3 weeks of the chick's life and is increasing significantly. For this reason, it is always necessary to search for most efficient systems for this purpose. In addition to that, the use of bioenergy is gaining importance since it is renewable and ecologically correct. A close coupled gasification/combustion system, using eucalyptus firewood (Eucalyptus grandis and/or Eucalyptus urophylla) as fuel, was tested with the objective of providing thermal comfort for the birds during their first 3 weeks after birth. An experiment was set up for this purpose in an industrial scale production facility. The results indicated that the gasification/combustion system is viable for space heating for chicks, does not alters significantly the air quality, regarding CO, CO{sub 2} and NH{sub 3} concentration inside poultry house, provides the best thermal comfort as compared to indirect fired furnaces and accounts for a 35% energy savings, leading to lower production costs. (author)

High temperature thermoacoustic heat pump

Energy Technology Data Exchange (ETDEWEB)

Tijani, H.; Spoelstra, S. [Energy research Centre of the Netherlands, 1755 ZG Petten (Netherlands)

2012-06-15

Thermoacoustic technology can provide new types of heat pumps that can be deployed in different applications. A thermoacoustic heat pumps can for example be applied in dwellings to generate cooling or heating. Typically, space and water heating makes up about 60% of domestics and offices energy consumption. The application of heat pumps can contribute to achieve energy savings and environmental benefits by reducing CO2 and NOx emissions. This paper presents the study of a laboratory scale thermoacoustic-Stirling heat pump operating between 10C and 80C which can be applied in domestics and offices. The heat pump is driven by a thermoacoustic-Stirling engine. The experimental results show that the heat pump pumps 250 W of heat at 60C at a drive ratio of 3.6% and 200 W at 80C at a drive ratio of 3.5 %. The performance for both cases is about 40% of the Carnot performance. The design, construction, and performance measurements of the heat pump will be presented and discussed.

High Temperature Thermoacoustic Heat Pump

Energy Technology Data Exchange (ETDEWEB)

Tijani, H.; Spoelstra, S. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

2012-07-15

Thermoacoustic technology can provide new types of heat pumps that can be deployed in different applications. Thermoacoustic heat pumps can for example be applied in dwellings to generate cooling or heating. Typically, space and water heating makes up about 60% of domestic and office energy consumption. The application of heat pumps can contribute to achieve energy savings and environmental benefits by reducing CO2 and NOx emissions. This paper presents the study of a laboratory scale thermoacoustic-Stirling heat pump operating between 10C and 80C which can be applied in domestics and offices. The heat pump is driven by a thermoacoustic-Stirling engine. The experimental results show that the heat pump pumps 250 W of heat at 60C at a drive ratio of 3.6 % and 200 W at 80C at a drive ratio of 3.5 %. The performance for both cases is about 40% of the Carnot performance. The design, construction, and performance measurements of the heat pump will be presented and discussed.

Performance demonstration of a high-power space-reactor heat-pipe design

International Nuclear Information System (INIS)

Merrigan, M.A.; Martinez, E.H.; Keddy, E.S.; Runyan, J.; Kemme, J.E.

1983-01-01

Performance of a 15.9-mm diam, 2-m long, artery heat pipe has been demonstrated at power levels to 22.6 kW and temperatures to 1500 0 K. The heat pipe employed lithium as a working fluid with distribution wicks and arteries fabricated from 400 mesh Mo-41 wt % Re screen. Molybdenum alloy (TZM) was used for the container. Peak axial power density attained in the testing was 19 kW/cm 2 at 1465 0 K. The corresponding radial flux density in the evaporator region of the heat pipe was 150 W/cm 2 . The extrapolated limit for the heat pipe at its 1500 0 K design point is 30 kW, corresponding to an axial flux density of 25 kW/cm 2 . Sonic and capillary limits for the design were investigated in the 1100 to 1500 0 K temperature range. Excellent agreement of measured and predicted temperature and power levels was observed

Space heating with ultra-low-temperature district heating - a case study of four single-family houses from the 1980s

DEFF Research Database (Denmark)

Østergaard, Dorte Skaarup; Svendsen, Svend

2017-01-01

. These benefits can be maximized if district heating temperatures are lowered as much as possible. In this paper we report on a project where 18 Danish single-family houses from the 1980s were supplied by ultra-low temperature district heating with a supply temperature as low as 45 degrees C for the main part...... of the year. The houses were heated by the existing hydraulic radiator systems, while domestic hot water was prepared by use of district heating and electric boosting. This paper evaluated the heating system temperatures that were necessary in order to maintain thermal comfort in four of the houses. First...... the four houses were modelled in the building simulation tool IDA ICE. The simulation models included the actual radiator sizes and the models were used to simulate the expected thermal comfort in the houses and resulting district heating return temperatures. Secondly measurements of the actual district...

Superconductor Particles As The Working Media Of A Heat Engine

Science.gov (United States)

Keefe, Peter D.

2011-12-01

A heat engine is presented in which the working media comprises a multiplicity of mutually isolated particles of Type I superconductor which are selectively processed through H-T phase space so as to convert a heat influx from a high temperature heat reservoir into a useful work output, wherein no heat is rejected to a low temperature heat reservoir.

Development of platform to compare different wall heat transfer packages for system analysis codes

International Nuclear Information System (INIS)

Kim, Min-Gil; Lee, Won Woong; Lee, Jeong Ik; Shin, Sung Gil

2016-01-01

System thermal hydraulic (STH) analysis code is used for analyzing and evaluating the safety of a designed nuclear system. The system thermal hydraulic analysis code typically solves mass, momentum and energy conservation equations for multiple phases with sets of selected empirical constitutive equations to close the problem. Several STH codes are utilized in academia, industry and regulators, such as MARS-KS, SPACE, RELAP5, COBRA-TF, TRACE, and so on. Each system thermal hydraulic code consists of different sets of governing equations and correlations. However, the packages and sets of correlations of each code are not compared quantitatively yet. Wall heat transfer mode transition maps of SPACE and MARS-KS have a little difference for the transition from wall nucleate heat transfer mode to wall film heat transfer mode. Both codes have the same heat transfer packages and correlations in most region except for wall film heat transfer mode. Most of heat transfer coefficients calculated for the range of selected variables of SPACE are the same with those of MARS-KS. For the intervals between 500K and 540K of wall temperature, MARS-KS selects the wall film heat transfer mode and Bromley correlation but SPACE select the wall nucleate heat transfer mode and Chen correlation. This is because the transition from nucleate boiling to film boiling of MARS-KS is earlier than SPACE. More detailed analysis of the heat transfer package and flow regime package will be followed in the near future

Atoms for space

Energy Technology Data Exchange (ETDEWEB)

Buden, D.

1990-10-01

Nuclear technology offers many advantages in an expanded solar system space exploration program. These cover a range of possible applications such as power for spacecraft, lunar and planetary surfaces, and electric propulsion; rocket propulsion for lunar and Mars vehicles; space radiation protection; water and sewage treatment; space mining; process heat; medical isotopes; and self-luminous systems. In addition, space offers opportunities to perform scientific research and develop systems that can solve problems here on Earth. These might include fusion and antimatter research, using the Moon as a source of helium-3 fusion fuel, and manufacturing perfect fusion targets. In addition, nuclear technologies can be used to reduce risk and costs of the Space Exploration Initiative. 1 fig.

Atoms for space

International Nuclear Information System (INIS)

Buden, D.

1990-10-01

Nuclear technology offers many advantages in an expanded solar system space exploration program. These cover a range of possible applications such as power for spacecraft, lunar and planetary surfaces, and electric propulsion; rocket propulsion for lunar and Mars vehicles; space radiation protection; water and sewage treatment; space mining; process heat; medical isotopes; and self-luminous systems. In addition, space offers opportunities to perform scientific research and develop systems that can solve problems here on Earth. These might include fusion and antimatter research, using the Moon as a source of helium-3 fusion fuel, and manufacturing perfect fusion targets. In addition, nuclear technologies can be used to reduce risk and costs of the Space Exploration Initiative. 1 fig

Synergies of wind power and electrified space heating: case study for Beijing.

Science.gov (United States)

Chen, Xinyu; Lu, Xi; McElroy, Michael B; Nielsen, Chris P; Kang, Chongqing

2014-01-01

Demands for electricity and energy to supply heat are expected to expand by 71% and 47%, respectively, for Beijing in 2020 relative to 2009. If the additional electricity and heat are supplied solely by coal as is the current situation, annual emissions of CO2 may be expected to increase by 59.6% or 99 million tons over this interval. Assessed against this business as usual (BAU) background, the present study indicates that significant reductions in emissions could be realized using wind-generated electricity to provide a source of heat, employed either with heat pumps or with electric thermal storage (ETS) devices. Relative to BAU, reductions in CO2 with heat pumps assuming 20% wind penetration could be as large as 48.5% and could be obtained at a cost for abatement of as little as $15.6 per ton of avoided CO2. Even greater reductions, 64.5%, could be realized at a wind penetration level of 40% but at a higher cost, $29.4 per ton. Costs for reduction of CO2 using ETS systems are significantly higher, reflecting the relatively low efficiency for conversion of coal to power to heat.

Heat-Pipe-Associated Localized Thermoelectric Power Generation System

Science.gov (United States)

Kim, Pan-Jo; Rhi, Seok-Ho; Lee, Kye-Bock; Hwang, Hyun-Chang; Lee, Ji-Su; Jang, Ju-Chan; Lee, Wook-Hyun; Lee, Ki-Woo

2014-06-01

The present study focused on how to improve the maximum power output of a thermoelectric generator (TEG) system and move heat to any suitable space using a TEG associated with a loop thermosyphon (loop-type heat pipe). An experimental study was carried out to investigate the power output, the temperature difference of the thermoelectric module (TEM), and the heat transfer performance associated with the characteristic of the researched heat pipe. Currently, internal combustion engines lose more than 35% of their fuel energy as recyclable heat in the exhaust gas, but it is not easy to recycle waste heat using TEGs because of the limited space in vehicles. There are various advantages to use of TEGs over other power sources, such as the absence of moving parts, a long lifetime, and a compact system configuration. The present study presents a novel TEG concept to transfer heat from the heat source to the sink. This technology can transfer waste heat to any location. This simple and novel design for a TEG can be applied to future hybrid cars. The present TEG system with a heat pipe can transfer heat and generate power of around 1.8 V with T TEM = 58°C. The heat transfer performance of a loop-type heat pipe with various working fluids was investigated, with water at high heat flux (90 W) and 0.05% TiO2 nanofluid at low heat flux (30 W to 70 W) showing the best performance in terms of power generation. The heat pipe can transfer the heat to any location where the TEM is installed.

Indoor unit for electric heat pump

Science.gov (United States)

Draper, R.; Lackey, R.S.; Fagan, T.J. Jr.; Veyo, S.E.; Humphrey, J.R.

1984-05-22

An indoor unit for an electric heat pump is provided in modular form including a refrigeration module, an air mover module, and a resistance heat package module, the refrigeration module including all of the indoor refrigerant circuit components including the compressor in a space adjacent the heat exchanger, the modules being adapted to be connected to air flow communication in several different ways as shown to accommodate placement of the unit in various orientations. 9 figs.

Solar-Heated Office Building -- Dallas, Texas

Science.gov (United States)

1982-01-01

Solar heating system designed to supply 87 percent of space heating and 100 percent of potable hot-water needs of large office building in Dallas, Texas. Unique feature of array serves as roofing over office lobby and gives building attractive triangular appearance. Report includes basic system drawings, test data, operating procedures, and maintenance instructions.

Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings: A case study of the Copenhagen district heating area in Denmark

International Nuclear Information System (INIS)

Harrestrup, M.; Svendsen, S.

2014-01-01

The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized heating plants that are too expensive to build in comparison with the potential energy savings in buildings. Long-term strategies for the existing building stock must ensure that costs are minimized and that investments in energy savings and new heating capacity are optimized and carried out at the right time. - Highlights: • We investigate how much heating consumption needs to be reduced in a district heating area. • We examine fossil-fuel-free supply vs. energy conservations in the building stock. • It is slightly cost-beneficial to invest in energy renovation from today for a societal point of view. • It is economically beneficial for district heating companies to invest in energy renovations from today. • The cost per delivered heat unit is lower when energy renovations are carried out from today

Logistics Reduction: Heat Melt Compactor

Data.gov (United States)

National Aeronautics and Space Administration — The Advanced Exploration Systems (AES) Logistics Reduction (LR) project Heat Melt Compactor (HMC) technology is a waste management technology. Currently, there are...

Multifunctional Hot Structure Heat Shield

Data.gov (United States)

National Aeronautics and Space Administration — This project is performing preliminary development of a Multifunctional Hot Structure (HOST) heat shield for planetary entry. Results of this development will...

Natural convection in an adiabatic vertical channel due to a dissipated heat element

International Nuclear Information System (INIS)

Ramos, M.A.M.S.

1986-01-01

An experimental study was perfomed on natural convection heat transfer to air in a vertical channel due to an isothermal heated element attached in one of the walls of the channel. The heated element dissipates heat due to the Joule effect. To determine the heat transfer coefficient, it is necessary to evaluate the heat transferred to air by natural convenction alone. Hence, the heat lost by the element due to conduction and radiation is evaluated in order to correct the measured heat transfer. The natural-convenction heat transfer coefficient is a function of the following parameters: the temperature difference between the element and the ambient air, the position of the element in the channel, and the channel spacing. An optimal value of the channel spacing, when the heat transfer coefficient attains its maximum value, was observed for each of the temperature difference investigated. These maximum values may be up to 25% higher than the value for the case of infinite spacing. Comparisons are made with results available in the literature for similar configurations, and the values found in this work are higher. (author) [pt

Heat Pipe-Assisted Thermoelectric Power Generation Technology for Waste Heat Recovery

Science.gov (United States)

Jang, Ju-Chan; Chi, Ri-Guang; Rhi, Seok-Ho; Lee, Kye-Bock; Hwang, Hyun-Chang; Lee, Ji-Su; Lee, Wook-Hyun

2015-06-01

Currently, large amounts of thermal energy dissipated from automobiles are emitted through hot exhaust pipes. This has resulted in the need for a new efficient recycling method to recover energy from waste hot exhaust gas. The present experimental study investigated how to improve the power output of a thermoelectric generator (TEG) system assisted by a wickless loop heat pipe (loop thermosyphon) under the limited space of the exhaust gas pipeline. The present study shows a novel loop-type heat pipe-assisted TEG concept to be applied to hybrid vehicles. The operating temperature of a TEG's hot side surface should be as high as possible to maximize the Seebeck effect. The present study shows a novel TEG concept of transferring heat from the source to the sink. This technology can transfer waste heat to any local place with a loop-type heat pipe. The present TEG system with a heat pipe can transfer heat and generate an electromotive force power of around 1.3 V in the case of 170°C hot exhaust gas. Two thermoelectric modules (TEMs) for a conductive block model and four Bi2Te3 TEMs with a heat pipe-assisted model were installed in the condenser section. Heat flows to the condenser section from the evaporator section connected to the exhaust pipe. This novel TEG system with a heat pipe can be placed in any location on an automobile.

Open Channel Natural Convection Heat Transfer on a Vertical Finned Plate

International Nuclear Information System (INIS)

Park, Joo Hyun; Heo, Jeong Hwan; Chung, Bum Jin

2013-01-01

The natural convection heat transfer of vertical plate fin was investigated experimentally. Heat transfer systems were replaced by mass-transfer systems, based on the analogy concept. The experimental results lie within the predictions of the existing heat transfer correlations of plate-fin for the natural convections. An overlapped thermal boundary layers caused increasing heat transfer, and an overlapped momentum boundary layers caused decreasing heat transfer. As the fin height increases, heat transfer was enhanced due to increased inflow from the open side of the fin spacing. When fin spacing and fin height are large, heat transfer was unaffected by the fin spacing and fin height. Passive cooling by natural convection becomes more and more important for the nuclear systems as the station black out really happened at the Fukushima NPPs. In the RCCS (Reactor Cavity Cooling System) of a VHTR (Very High Temperature Reactor), natural convection cooling through duct system is adopted. In response to the stack failure event, extra cooling capacity adopting the fin array has to be investigated. The finned plate increases the surface area and the heat transfer increases. However, the plate of fin arrays may increase the pressure drop and the heat transfer decreases. Therefore, in order to enhance the passive cooling with fin arrays, the parameters for the fin arrays should be optimized. According to Welling and Wooldridge, a natural convection on vertical plate fin is function of Gr, Pr, L, t, S, and H. The present work investigated the natural convection heat transfer of a vertical finned plate with varying the fin height and the fin spacing. In order achieve high Rayleigh numbers, an electroplating system was employed and the mass transfer rates were measured using a copper sulfate electroplating system based on the analogy concept

Sandwich Core Heat-Pipe Radiator for Power and Propulsion Systems

Science.gov (United States)

Gibson, Marc; Sanzi, James; Locci, Ivan

2013-01-01

Next-generation heat-pipe radiator technologies are being developed at the NASA Glenn Research Center to provide advancements in heat-rejection systems for space power and propulsion systems. All spacecraft power and propulsion systems require their waste heat to be rejected to space in order to function at their desired design conditions. The thermal efficiency of these heat-rejection systems, balanced with structural requirements, directly affect the total mass of the system. Terrestrially, this technology could be used for thermal control of structural systems. One potential use is radiant heating systems for residential and commercial applications. The thin cross section and efficient heat transportability could easily be applied to flooring and wall structures that could evenly heat large surface areas. Using this heat-pipe technology, the evaporator of the radiators could be heated using any household heat source (electric, gas, etc.), which would vaporize the internal working fluid and carry the heat to the condenser sections (walls and/or floors). The temperature could be easily controlled, providing a comfortable and affordable living environment. Investigating the appropriate materials and working fluids is needed to determine this application's potential success and usage.

Upright heat exchanger

International Nuclear Information System (INIS)

Martoch, J.; Kugler, V.; Krizek, V.; Strmiska, F.

1988-01-01

The claimed heat exchanger is characteristic by the condensate level being maintained directly in the exchanger while preserving the so-called ''dry'' tube plate. This makes it unnecessary to build another pressure vessel into the circuit. The design of the heat exchanger allows access to both tube plates, which facilitates any repair. Another advantage is the possibility of accelerating the indication of leakage from the space of the second operating medium which is given by opening the drainage pipes of the lower bundle into the collar space and from there through to the indication pipe. The exchanger is especially suitable for deployment in the circuits of nuclear power plants where the second operating medium will be hot water of considerably lower purity than is that of the condensate. A rapid display of leakage can prevent any long-term penetration of this water into the condensate, which would result in worsening water quality in the entire secondary circuit of the nuclear power plant. (J.B.). 1 fig

A numerical investigation of γ-Al2O3-water nanofluids heat transfer and pressure drop in a shell and tube heat exchanger

Directory of Open Access Journals (Sweden)

P. Shahmohammadi

2016-01-01

Full Text Available The effect of γ-Al2O3 nanoparticles on heat transfer rate, baffle spacing and pressure drop in the shell side of small shell and tube heat exchangers was investigated numerically under turbulent regime. γ-Al2O3-water nanofluids and pure water were used in the shell side and the tube side of heat exchangers, respectively. Since the properties of γ-Al2O3-water nanofluids were variable, they were defined using the user define function. The results revealed that heat transfer and pressure drop were increased with mass flow rate as well as baffle numbers. Adding nanoparticles to the based fluid did not have a significant effect on pressure drop in the shell side. The best heat transfer performance of heat exchangers was for γ-Al2O3-water 1 vol.% and higher nanoparticles concentration was not suitable. The suitable baffle spacing was 43.4% of the shell diameter, showing a good agreement with Bell-Delaware method.

Solar heating and cooling demonstration project at the Florida Solar Energy Center

Energy Technology Data Exchange (ETDEWEB)

Hankins, J.D.

1980-02-01

The retrofitted solar heating and cooling system installed at the Florida Solar Energy Center is described. Information is provided on the system's test, operation, controls, hardware and installation, including detailed drawings. The Center's office building, approximately 5000 square feet of space, with solar air conditioning and heating as a demonstration of the technical feasibility is located just north of Port Canaveral, Florida. The system was designed to supply approximately 70% of the annual cooling and 100% of the heating load. The project provides unique high-temperature, non-imaging, non-tracking, evacuated-tube collectors. The design of the system was kept simple and employs five hydronic loops. They are energy collection, chilled water production, space cooling, space heating and energy rejection.

Microplate Heat Exchanger, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple cooling...

General-purpose heat source project and space nuclear safety and fuels program. Progress report

International Nuclear Information System (INIS)

Maraman, W.J.

1980-02-01

Studies related to the use of 238 PuO 2 in radioisotopic power systems carried out for the Advanced Nuclear Systems and Projects Division of LASL are presented. The three programs involved are: general-purpose heat source development; space nuclear safety; and fuels program. Three impact tests were conducted to evaluate the effects of a high temperature reentry pulse and the use of CBCF on impact performance. Additionally, two 238 PuO 2 pellets were encapsulated in Ir-0.3% W for impact testing. Results of the clad development test and vent testing are noted. Results of the environmental tests are summarized. Progress on the Stirling isotope power systems test and the status of the improved MHW tests are indicated. The examination of the impact failure of the iridium shell of MHFT-65 at a fuel pass-through continued. A test plan was written for vibration testing of the assembled light-weight radioisotopic heater unit. Progress on fuel processing is reported

A numerical study of vorticity-enhanced heat transfer

Science.gov (United States)

Wang, Xiaolin; Alben, Silas

2012-11-01

The Glezer lab at Georgia Tech has found that vorticity produced by vibrated reeds can improve heat transfer in electronic hardware. Vortices enhance forced convection by boundary layer separation and thermal mixing in the bulk flow. In this work, we simulate the heat transfer process in a 3-dimensional plate-fin heat sink. We propose a simplified model by considering flow and temperature in a 2-D channel, and extend the model to the third dimension using a 1-D heat fin model. We simulate periodically steady-state solutions. We determine how the global Nusselt number is increased, depending on the vortices' strengths and spacings, in the parameter space of Reynolds and Peclet numbers. We find a surprising spatial oscillation of the local Nusselt number due to the vortices. Support from NSF-DMS grant 1022619 is acknowledged.

Heat pumps. Tax credit: repercussions in the profession; Pompes a chaleur. Credit d'impot: des retentissements dans la profession

Energy Technology Data Exchange (ETDEWEB)

Lux, C.

2005-04-01

The French by-law from February 9, 2005, which completes the 2005 finances law, precises the equipments concerned by a 40% tax credit. It takes into account only the geothermal and air/water heat pumps for space heating with a coefficient of performance (COP) {>=} 3. The air/air heat pumps are excluded from this purview while they were included in 2004. This article presents the contrasted reactions of some professionals in front of this measure. The tax credit concerns only the heat pumps for space heating purposes, while the air/air heat pumps can produce indifferently heat and coldness and sometimes with different COPs in space heating and in space cooling. (J.S.)

Space Shuttle Orbiter AFT heat shield seal

Science.gov (United States)

Walkover, L. J.

1979-01-01

The evolution of the orbiter aft heat shield seal (AHSS) design, which involved advancing mechanical seal technology in severe thermal environment is discussed. The baseline design, various improvements for engine access, and technical problem solution are presented. It is a structure and mechanism at the three main propulsion system (MPS) engine interfaces to the aft compartment structure. Access to each MPS engine requires disassembly and removal of the AHSS. Each AHSS accommodates the engine movement, is exposed to an extremely high temperature environment, and is part of the venting control of the aft compartment.

Recovering heat from waste air from stables

Energy Technology Data Exchange (ETDEWEB)

1983-01-01

A milk cow gives off 35.7 kW h/d via its body, excreta and urine. 68.4% of this is body heat. Part of this waste heat escapes with the waste air from the cowsheds. The heat can be recovered from the waste air by an air/air heat exchanger. The air is collected and taken to a heat exchanger. In the heat exchanger, fresh air is heated by the waste air, and is distributed over the cowshed by a system of ducts. The heated waste air escapes through a central chimney at the end of the heat exchanger. It is sensible to fit the heat exchanger above the cowshed roof, if there is sufficient space available and the chimney should run upwards from the cowshed. A double heat exchanger makes it possible to allocate each half of the cowshed to half of the heat exchanger.

Heat and fluid flow properties of circular impinging jet with a low nozzle to plate spacing. Improvement by nothched nozzle; Nozzle heibankan kyori ga chiisai baai no enkei shototsu funryu no ryudo dennetsu tokusei. Kirikaki nozzle ni yoru kaizen kojo

Energy Technology Data Exchange (ETDEWEB)

Shakouchih, T. [Mie University, Mie (Japan). Faculty of Engineering; Matsumoto, A.; Watanabe, A.

2000-10-25

It is well known that as decreasing the nozzle to plate spacing considerably the heat transfer coefficient of circular impinging jet, which impinges to the plate normally, increases remarkably. At that time, the flow resistance of nozzle-plate system also increases rapidly. In this study, in order to reduce the flow resistance and to enhance the heat transfer coefficient of the circular impinging jet with a considerably low nozzle to plate spacing, a special nozzle with notches is proposed, and considerable improvement of the flow and heat transfer properties are shown. The mechanism of enhancement of the heat transfer properties is also discussed. (author)

Residential gas-fired sorption heat pumps. Test and technology evaluation

Energy Technology Data Exchange (ETDEWEB)

Naeslund, M.

2008-12-15

Heat pumps may be the next step in gas-fired residential space heating. Together with solar energy it is an option to combine natural gas and renewable energy. Heat pumps for residential space heating are likely to be based on the absorption or adsorption process, i.e. sorption heat pumps. Manufacturers claim that the efficiency could reach 140-160%. The annual efficiency will be lower but it is clear that gas-fired heat pumps can involve an efficiency and technology step equal to the transition from non-condensing gas boilers with atmospheric burners to condensing boilers. This report contains a review of the current sorption gas-fired heat pumps for residential space heating and also the visible development trends. A prototype heat pump has been laboratory tested. Field test results from Germany and the Netherlands are also used for a technology evaluation. The tested heat pump unit combines a small heat pump and a supplementary condensing gas boiler. Field tests show an average annual efficiency of 120% for this prototype design. The manufacturer abandoned the tested design during the project period and the current development concentrates on a heat pump design only comprising the heat pump, although larger. The heat pump development at three manufacturers in Germany indicates a commercial stage around 2010-2011. A fairly high electricity consumption compared to traditional condensing boilers was observed in the tested heat pump. Based on current prices for natural gas and electricity the cost savings were estimated to 12% and 27% for heat pumps with 120% and 150% annual efficiency respectively. There is currently no widespread performance testing procedure useful for annual efficiency calculations of gas-fired heat pumps. The situation seems to be clearer for electric compression heat pumps regarding proposed testing and calculation procedures. A German environmental label exists and gasfired sorption heat pumps are also slightly treated in the Eco-design work

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.

Experimental investigation on Heat Transfer Performance of Annular Flow Path Heat Pipe

International Nuclear Information System (INIS)

Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol

2015-01-01

Mochizuki et al. was suggested the passive cooling system to spent nuclear fuel pool. Detail analysis of various heat pipe design cases was studied to determine the heat pipes cooling performance. Wang et al. suggested the concept PRHRS of MSR using sodium heat pipes, and the transient performance of high temperature sodium heat pipe was numerically simulated in the case of MSR accident. The meltdown at the Fukushima Daiichi nuclear power plants alarmed to the dangers of station blackout (SBO) accident. After the SBO accident, passive decay heat removal systems have been investigated to prevent the severe accidents. Mochizuki et al. suggested the heat pipes cooling system using loop heat pipes for decay heat removal cooling and analysis of heat pipe thermal resistance for boiling water reactor (BWR). The decay heat removal systems for pressurized water reactor (PWR) were suggested using natural convection mechanisms and modification of PWR design. Our group suggested the concept of a hybrid heat pipe with control rod as Passive IN-core Cooling System (PINCs) for decay heat removal for advanced nuclear power plant. Hybrid heat pipe is the combination of the heat pipe and control rod. In the present research, the main objective is to investigate the effect of the inner structure to the heat transfer performance of heat pipe containing neutron absorber material, B 4 C. The main objective is to investigate the effect of the inner structure in heat pipe to the heat transfer performance with annular flow path. ABS pellet was used instead of B 4 C pellet as cylindrical structures. The thermal performances of each heat pipes were measured experimentally. Among them, concentric heat pipe showed the best performance compared with others. 1. Annular evaporation section heat pipe and annular flow path heat pipe showed heat transfer degradation. 2. AHP also had annular vapor space and contact cooling surface per unit volume of vapor was increased. Heat transfer coefficient of

Space-time evolution of the power absorbed by creating and heating a hydrogen plasma column by a pulsed laser beam

International Nuclear Information System (INIS)

Pincosy, Philip; Dufresne, Daniel; Bournot, Philippe; Caressa, J.-P.; Autric, Michel

1976-01-01

Space-time measurements of light intensity are presented for the analysis of the processes involved in the creation and heating of an under-dense hydrogen plasma column by a pulsed CO 2 laser beam. The laser beam trapping due to the rapid development of a radial electron density gradient is specifically demonstrated. Time measurements of the changes in the laser power longitudinally transmitted through the plasma give evidence for a significant absorption of the incident power during the first 150 nanoseconds of the interaction [fr

Physical and Theoretical Models of Heat Pollution Applied to Cramped Conditions Welding Taking into Account the Different Types of Heat

Science.gov (United States)

Bulygin, Y. I.; Koronchik, D. A.; Legkonogikh, A. N.; Zharkova, M. G.; Azimova, N. N.

2017-05-01

The standard k-epsilon turbulence model, adapted for welding workshops, equipped with fixed workstations with sources of pollution took into account only the convective component of heat transfer, which is quite reasonable for large-volume rooms (with low density distribution of sources of pollution) especially the results of model calculations taking into account only the convective component correlated well with experimental data. For the purposes of this study, when we are dealing with a small confined space where necessary to take account of the body heated to a high temperature (for welding), located next to each other as additional sources of heat, it can no longer be neglected radiative heat exchange. In the task - to experimentally investigate the various types of heat transfer in a limited closed space for welding and behavior of a mathematical model, describing the contribution of the various components of the heat exchange, including radiation, influencing the formation of fields of concentration, temperature, air movement and thermal stress in the test environment. Conducted field experiments to model cubic body, allowing you to configure and debug the model of heat and mass transfer processes with the help of the developed approaches, comparing the measurement results of air flow velocity and temperature with the calculated data showed qualitative and quantitative agreement between process parameters, that is an indicator of the adequacy of heat and mass transfer model.

Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia

Science.gov (United States)

1981-01-01

A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

District heating

International Nuclear Information System (INIS)

Hansen, L.

1993-01-01

The environmental risks and uncertainties of a high-energy future are disturbing and give rise to several reservations concerning the use of fossil fuels. A number of technologies will help to reduce atmospheric pollution. In Denmark special importance is attached to the following: Energy conservation. Efficient energy conversion. Renewable energy sources. District heating, combined production of heat and power. Many agree that district heating (DH), produced by the traditional heat-only plant, and combined heat and power (CHP) have enormous potential when considering thermal efficiency and lowered environmental impacts: The basic technology of each is proven, it would be relatively simple to satisfy a substantial part of the energy demand, and their high efficiencies mean reduced pollution including greenhouse gas emissions. This is especially important in high population density areas - the obviously preferred sites for such energy generation. Compared with individual heating DH can provide a community with an operationally efficient and most often also an economically competitive heat supply. This is particularly true under the circumstances where the DH system is supplied from CHP plants. Their use results in very substantial improvements in overall efficiency. Further environmental improvements arise from the reduced air pollution obtainable in reasonably large CHP plants equipped with flue gas cleaning to remove particles, sulphur dioxide, and nitrogen acids. As a consequence of these considerations, DH plays an important role in fulfilling the space and water heating demand in many countries. This is especially the case in Denmark where this technology is utilised to a very great extent. Indeed, DH is one of the reasons why Denmark has relatively good air quality in the cities. (au)

Development of an air heating system for single family housing

DEFF Research Database (Denmark)

Afshari, Alireza; Gunner, Amalie; Nikolaisen, Christian Grønborg

2017-01-01

The initial objective of the project was to break with common thinking about Space heating and to document that air heating can be used as the sole source of heating in a single Family house. The basic idea is that the ventilation must be installed in any case and it may equally well form the heat...

Performance analysis of diesel engine heat pump incorporated with heat recovery

International Nuclear Information System (INIS)

Shah, N.N.; Huang, M.J.; Hewitt, N.J.

2016-01-01

Highlights: • Diesel engine heat pump with heat recovery. • Water-to-water source heat pump based on R134a. • Possibility for different flow temperature for heat distribution system. • Possible retrofit application in off-gas or weak electricity network area. • Potential to diversify use of fossil fuel, primary energy and CO_2 emission savings. - Abstract: This paper presents experimental study of diesel engine heat pump (DEHP) system to find potential as retrofit technology in off-gas or weak electricity network area to replace existing gas/oil/electric heating system in domestic sector. Test set-up of diesel engine driven water-to-water heat pump system was built which included heat recovery arrangement from the engine coolant & exhaust gas. The system was designed to meet typical house heating demand in Northern Ireland. Performance of DEHP was evaluated to meet house-heating demand at different flow temperature (35, 45, 55 & 65 °C), a typical requirement of underfloor space heating, medium/high temperature radiators and domestic hot water. The performance was evaluated against four-evaporator water inlet temperature (0, 5, 10 & 15 °C) and at three different engine speed 1600, 2000 & 2400 rpm. Experiment results were analysed in terms of heating/cooling capacity, heat recovery, total heat output, primary energy ratio (PER), isentropic efficiency, etc. Test results showed that DEHP is able to meet house-heating demand with help of heat recovery with reduced system size. Heat recovery contributed in a range of 22–39% in total heat output. It is possible to achieve high flow temperature in a range of 74 °C with help of heat recovery. Overall system PER varied in a range of 0.93–1.33. Speed increment and flow temperature has significant impact on heat recovery, total heat output and PER. A case scenario with different flow temperature to match house-heating demand has been presented to show working potential with different heat distribution system

Modelling of Thermal Behavior of Borehole Heat Exchangers of Geothermal Heat Pump Heating Systems

Directory of Open Access Journals (Sweden)

Gornov V.F.

2016-01-01

Full Text Available This article reports results of comparing the accuracy of the software package “INSOLAR.GSHP.12”, modeling non-steady thermal behavior of geothermal heat pump heating systems (GHCS and of the similar model “conventional” using finite difference methods for solving spatial non-steady problems of heat conductivity. The software package is based on the method of formulating mathematical models of thermal behavior of ground low-grade heat collection systems developed by INSOLAR group of companies. Equations of mathematical model of spatial non-steady thermal behavior of ground mass of low-grade heat collection system obtained by the developed method have been solved analytically that significantly reduced computing time spent by the software complex “INSOLAR.GSHP.12” for calculations. The method allows to turn aside difficulties associated with information uncertainty of mathematical models of the ground thermal behavior and approximation of external factors affecting the ground. Use of experimentally obtained information about the ground natural thermal behavior in the software package allows to partially take into account the whole complex of factors (such as availability of groundwater, their velocity and thermal behavior, structure and arrangement of ground layers, the Earth’s thermal background, precipitation, phase transformations of moisture in the pore space, and more, significantly influencing the formation of thermal behavior of the ground mass of a low-grade geothermal heat collection system. Numerical experiments presented in the article confirmed the high convergence of the results obtained through the software package “INSOLAR.GSHP.12” with solutions obtained by conventional finite-difference methods.

Solar heating systems for houses. A design handbook for solar combisystems

International Nuclear Information System (INIS)

Weiss, W.

2003-11-01

A handbook giving guidance on systems for providing combined solar space heating and solar water heating for houses has been produced by an international team. The guidance focuses on selection of the optimum combi-system for groups of single-family houses and multi-family houses. Standard classification and evaluation procedures are described. The book should be a valuable tool for building engineers, architects, solar manufacturers and installers of solar solar energy systems, and anyone interested in optimizing combined water and space heating solar systems

Sodium heat pipe module test for the SAFE-30 reactor prototype

International Nuclear Information System (INIS)

Reid, Robert S.; Sena, J. Tom; Martinez, Adam L.

2001-01-01

Reliable, long-life, low-cost heat pipes can enable safe, affordable space fission power and propulsion systems. Advanced versions of these systems can in turn allow rapid access to any point in the solar system. Twelve stainless steel-sodium heat pipe modules were built and tested at Los Alamos for use in a non-nuclear thermohydraulic simulation of the SAFE-30 reactor (Poston et al., 2000). SAFE-30 is a near-term, low-cost space fission system demonstration. The heat pipes were designed to remove thermal power from the SAFE-30 core, and transfer this power to an electrical power conversion system. These heat pipe modules were delivered to NASA Marshall Space Flight Center in August 2000 and were assembled and tested in a prototypical configuration during September and October 2000. The construction and test of one of the SAFE-30 modules is described

Initial tests of thermoacoustic space power engine

International Nuclear Information System (INIS)

Backhaus, S.N.

2002-01-01

Future NASA deep-space missions will require radioisotope-powered electric generators that are just as reliable as current RTGs, but more efficient and of higher specific power (Wikg). Thennoacoustic engines at the -1-kW scale have converted high-temperature heat into acoustic, or PV, power without moving parts at 30% efficiency. Consisting of only tubes and a few heat exchangers, thennoacoustic engines are low mass and promise to be highly reliable. Coupling a thennoacoustic engine to a low mass, highly reliable and efficient linear alternator will create a heat-driven electric generator suitable for deep-space applications. Conversion efficiency data will be presented on a demonstration thennoacoustic engine designed for the 1 00-Watt power range.

Free-piston Stirling technology for space power

Science.gov (United States)

Slaby, Jack G.

1989-01-01

An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA's new Civil Space Technology Initiative (CSTI). The overall goal of CSTI's High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed here is the completion of the Space Power Demonstrator Engine (SPDE) testing-culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engine (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding.

Solar assisted heat pump on air collectors: A simulation tool

Energy Technology Data Exchange (ETDEWEB)

Karagiorgas, Michalis; Galatis, Kostas; Tsagouri, Manolis [Department of Mechanical Engineering Educators, ASPETE, N. Iraklio, GR 14121 (Greece); Tsoutsos, Theocharis [Environmental Engineering Dept., Technical University of Crete, Technical University Campus, GR 73100, Chania (Greece); Botzios-Valaskakis, Aristotelis [Centre for Renewable Energy Sources (CRES), 19th km Marathon Ave., GR 19001, Pikermi (Greece)

2010-01-15

The heating system of the bioclimatic building of the Greek National Centre for Renewable Energy Sources (CRES) comprises two heating plants: the first one includes an air source heat pump, Solar Air Collectors (SACs) and a heat distribution system (comprising a fan coil unit network); the second one is, mainly, a geothermal heat pump unit to cover the ground floor thermal needs. The SAC configuration as well as the fraction of the building heating load covered by the heating plant are assessed in two operation modes; the direct (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but indirectly into the evaporator of the air source heat pump). The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, saving electrical power consumed by the compressor of the heat pump, and therefore, at optimizing the coefficient of performance (COP) of the heat pump due to the increased intake of ambient thermal energy by means of the SAC. Results are given for three research objectives: assessment of the heat pump efficiency whether in direct or indirect heating mode; Assessment of the overall heating plant efficiency on a daily or hourly basis; Assessment of the credibility of the suggested simulation model TSAGAIR by comparing its results with the TRNSYS ones. (author)