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06456 Performance of residential refrigerators with ternary blends
14
Heat pumps
Error rstimatlon In bin method energy calculations 95/06449 Hanby, V. I. Applied Energy, 1995, 52, (1). 35-45. The use of the bin method for energy calculations in heated and cooled buildings entails a compromise between the calculation time taken and the increased accuracy of using a larger numbers of bins. A deterministic expression has been developed which can be used to predict the error attributable to different degrees of discretixation. The expression was tested using two typical calculation problems, which were run using both binned input data and the parent time-series data files. The expression was found to give a satisfactory prediction of the error due to discretization. Hydronlc radlant cooling - Prellmlnary assessment 95/06450 Feustel, H. E. and Stetiu, C. Energy & Build., 1995, 22, (3), 193-205. A significant amount of the electrical ener y used to cool non-residential buildings equipped with all-air systems is %rawn by the fans that transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the b’itildingby separatmg the tasks of ventilation and thermal conditionmg.YDue to the phystcal properties of water, hydronic systems can transport a given amount of thermal energy and use less than 5% of the otherwise necessary fan energy. This improvement alone significantly reduces the energy consumption and peak-power requirements of the air conditioning system. Radiant cooling has never penetrated the US markets significantly. The scope of this survey is to show the advantages of radiant cooling in combination with hydronic thermal distribution systems, as compared to the commonly-used all-air systems. 95l66461 Linear programming applied to an lndustrlal bulldlng with several available hot refuse flows I Bojic, M. et al., Energy, Oct. 1995, 20, (IO), 1067-1074. The authors use a recovery heat exchanger (RHE) in an industrial building to heat incoming air for space heating by using the heat contents of some of the refuse hot-air flows (RAF). Several RAFs are often available with different flow rates and temperatures. A proper scenario for use of their heat contents is essential for efficient management of the energy system. Using a steady-state, bottom-up approach, they have obtained a set of equations that have linearized. Linear programming (LP) is then used and LINE software has been developed. This software has been used for an industrial building with three RAFs to obtain a use scenario corresponding to the highest energy-saving efficiency and minimum life-cycle costs of the RHE.
95/06455 Passlve heat transfer enhancement techniques applied to compact bubble absorber design Merrill, T. L. et al., J. of Enhanced Heat Transfer, 1995, 2. (3). 199-208. The aper presents performance results and analysis for three compact bubb Pe absorbers developed for generator-absorber heat exchange abso tion cycles. The absorbers em loy passive heat transfer enhancement tee?: niques, namely repeated roug Kness, spiral flutes, and internal spacers. The selectton of enhancement techniques was done after a controlling heat transfer resistance analysis of a baseline absorber was completed. 95106466 Performance of rssldsntlal rsfrlgsrators with ternary blends &ri3”; M. and Tulej, P. J. Inr. J. Energy Research, Sep. 1995, 19, (7), Comparative performance studies of ternary blends proposed as substitutes for CFC-12 are presented in this study. The experimental set-up includes a domestic refrigerator for evaluation of blend performance. Experimental data shows that the ternary blend NARM-12 consumed 35% less energy than CFC-12, and exhibits shorter cycles at comparable pressure ratios than CFC-12. 95106467 Testing and optlmlzlng the performance of a floorbased task condltlonlng system Bauman, F. S. er af., Energy & Build., 1995, 22, (3) 173-186. During recent years an increasing amount of attention has been paid to air distribution systems that individually condition the immediate environments of offtce workers within their workstations. As with task lighting systems, the controls for these ‘task conditioning’ systems are partially or entirely decentralized and under the control of the occupants. Among the primary types of task conditioning systems (floor-, desktop- and partitionbased), floor-based desi s are the most common, having been widely developed and used in s outh Africa and Europe, and are now gaining acceptance in the USA. The paper reports the results of recently completed laboratory measurements investigating the thermal performance of a floorbased task conditioning system.
14 HEAT PUMPS
EP”
Integrated
thermochemical
heat-pumpknergy-
95/66452 Measured air-condltlonlng and thermal performance of a Thal residential bulldlng Parker, D. S. Energy, Sep. 1995, 20, (9), 997-914. tttoning * and thermal performThe author describes the measured air-con &l. ante of a typical Thai single-family residence. Although the measurements represent a single case study, it is the first time that an analysis has been performed on a Thai house with typical modem construction. In such buildings, the lack of building thermal insulation, the utilization of nonducted au-conditioning equipment and the night-only usage patterns are quite different from conditions prevailing in Western-style buildings. Our results show that reduction to ceiling heat transfer in residential Thai buildings is fundamental to improving cooling energy efficiency.
Tahat, M. A. et al., Int. J. Energy Research, Sep. 1995, 19, (7) 603-613. The feasibility of employing activated alumina and water, as reversible reaction pairs, in an integrated thermochemical heat-pump/energy-store has been studied theoretically and experimentally. The use of such a heat pum for the provision of heating and cooling applications has been investigate If. With the activated alumina absorbing water by up to 45 +/- 1% of the dry alumina’s weight, a heat of adsorption of 2.92 +/- 0.1 MJ/kg of water has been achieved.
0 tlmlzatlon of the speclflc rats of refrigeration In 95166453 combined refrPgeratlon cycles Chen, L. et al., Energy, Oct. 1995, 20, (lo), 1049-1053. The optimization problem of a combined refrigeration cycle formed by two endoreversible Carnot refrigeration cycles m series without intermediate reservoirs has been studied using finite-time thermodynamics. The fundamental relation between cooling quantity and coefficient of erformance (COP) of the combined cycle is derived for a general physica Ymodel of a combined c cle. Relations are derived between the SROR (=optimal specific rate otyrefrigeration, i.e. the average rate of refrigeration per unit of total heat-transfer surface area) and the COP for a piston-type, stable flow model of combined cycles. The results may be extended to an endoreversible, combined refrigeration cycle formed by more than two endoreversible Carnot refrigeration cycles.
Enhanced nucleate boiling surfaces are currently used in refrigeration and orocess heat exchanaers. Enhanced boilinn surfaces offer ootential for other applications, i&ding cooling of elec;onic equi ment. ?‘he possibility that the performance of such enhanced boiling su Kaces may be further improved by surface oxidation is addressed in this work. Ahhough the mechanism is not fully understood the current results suggest an important industrial application. The paper describes an apparatus and procedures for expanding the current limited data base for the performance of enhanced surface in pool boiling. The results of this study and the related methodology should help others address key issues of the surface geometry, oxidation, roughness and contact angle effects on nucleate pool boiling.
95106459 Pool bolllng of R-11 refrigerant and water on oxldlzed enhanced tubes irnndIo&mu, H. E. et al., J. of Enhanced Heat Transfer, 1995, 2, (3), -
.
15 ENVIRONMENT 95106454 An overview of chlorine-free refrigerants for centrifugal chillers Goktun, S. Energy, Sep. 1995, 20, (9) 937-940. Criteria are described for ideal working substances in centrifugal chillers. Chlorine-free fluorinated ethers and hydrocarbons are being considered as potential replacement for R-11, R-12 and R-114. Corn arisons are made in terms of ecological and thermophysical properties anx standard air-conditioning parameters for working substances which can be used without change of system design. R-245ca and E245fa are promising alternatives to R-11 for the low-capacity range, and R-134a is the best retrofit refrigerant for R-12 in the medium-capactty range. R-236ea, R-236ca? R-236fa, R236cb, and E-134 are promising refrigerants for replacmg R-114 in centrifugal chillers for the high-capacity range.
456
Fuel and Energy Abstracts November 1995
Pollution,
Health Protection,
Safety
95lO6460 Activated coke technology for flue gss clsanlng In waste and special waste lnclnsratlon plants Cleve,U. Brennst.-Waerme-KraF, 1994, 46, (lo), V25-37. (In German) Discusses the various cleaning technologies for flue gases from waste and special waste incinerators, including safeguards, and experiences of activated coke technology. Reports on the spent activated coke disposal by desorption or combustion.
Heat pumps
Error rstimatlon In bin method energy calculations 95/06449 Hanby, V. I. Applied Energy, 1995, 52, (1). 35-45. The use of the bin method for energy calculations in heated and cooled buildings entails a compromise between the calculation time taken and the increased accuracy of using a larger numbers of bins. A deterministic expression has been developed which can be used to predict the error attributable to different degrees of discretixation. The expression was tested using two typical calculation problems, which were run using both binned input data and the parent time-series data files. The expression was found to give a satisfactory prediction of the error due to discretization. Hydronlc radlant cooling - Prellmlnary assessment 95/06450 Feustel, H. E. and Stetiu, C. Energy & Build., 1995, 22, (3), 193-205. A significant amount of the electrical ener y used to cool non-residential buildings equipped with all-air systems is %rawn by the fans that transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the b’itildingby separatmg the tasks of ventilation and thermal conditionmg.YDue to the phystcal properties of water, hydronic systems can transport a given amount of thermal energy and use less than 5% of the otherwise necessary fan energy. This improvement alone significantly reduces the energy consumption and peak-power requirements of the air conditioning system. Radiant cooling has never penetrated the US markets significantly. The scope of this survey is to show the advantages of radiant cooling in combination with hydronic thermal distribution systems, as compared to the commonly-used all-air systems. 95l66461 Linear programming applied to an lndustrlal bulldlng with several available hot refuse flows I Bojic, M. et al., Energy, Oct. 1995, 20, (IO), 1067-1074. The authors use a recovery heat exchanger (RHE) in an industrial building to heat incoming air for space heating by using the heat contents of some of the refuse hot-air flows (RAF). Several RAFs are often available with different flow rates and temperatures. A proper scenario for use of their heat contents is essential for efficient management of the energy system. Using a steady-state, bottom-up approach, they have obtained a set of equations that have linearized. Linear programming (LP) is then used and LINE software has been developed. This software has been used for an industrial building with three RAFs to obtain a use scenario corresponding to the highest energy-saving efficiency and minimum life-cycle costs of the RHE.
95/06455 Passlve heat transfer enhancement techniques applied to compact bubble absorber design Merrill, T. L. et al., J. of Enhanced Heat Transfer, 1995, 2. (3). 199-208. The aper presents performance results and analysis for three compact bubb Pe absorbers developed for generator-absorber heat exchange abso tion cycles. The absorbers em loy passive heat transfer enhancement tee?: niques, namely repeated roug Kness, spiral flutes, and internal spacers. The selectton of enhancement techniques was done after a controlling heat transfer resistance analysis of a baseline absorber was completed. 95106466 Performance of rssldsntlal rsfrlgsrators with ternary blends &ri3”; M. and Tulej, P. J. Inr. J. Energy Research, Sep. 1995, 19, (7), Comparative performance studies of ternary blends proposed as substitutes for CFC-12 are presented in this study. The experimental set-up includes a domestic refrigerator for evaluation of blend performance. Experimental data shows that the ternary blend NARM-12 consumed 35% less energy than CFC-12, and exhibits shorter cycles at comparable pressure ratios than CFC-12. 95106467 Testing and optlmlzlng the performance of a floorbased task condltlonlng system Bauman, F. S. er af., Energy & Build., 1995, 22, (3) 173-186. During recent years an increasing amount of attention has been paid to air distribution systems that individually condition the immediate environments of offtce workers within their workstations. As with task lighting systems, the controls for these ‘task conditioning’ systems are partially or entirely decentralized and under the control of the occupants. Among the primary types of task conditioning systems (floor-, desktop- and partitionbased), floor-based desi s are the most common, having been widely developed and used in s outh Africa and Europe, and are now gaining acceptance in the USA. The paper reports the results of recently completed laboratory measurements investigating the thermal performance of a floorbased task conditioning system.
14 HEAT PUMPS
EP”
Integrated
thermochemical
heat-pumpknergy-
95/66452 Measured air-condltlonlng and thermal performance of a Thal residential bulldlng Parker, D. S. Energy, Sep. 1995, 20, (9), 997-914. tttoning * and thermal performThe author describes the measured air-con &l. ante of a typical Thai single-family residence. Although the measurements represent a single case study, it is the first time that an analysis has been performed on a Thai house with typical modem construction. In such buildings, the lack of building thermal insulation, the utilization of nonducted au-conditioning equipment and the night-only usage patterns are quite different from conditions prevailing in Western-style buildings. Our results show that reduction to ceiling heat transfer in residential Thai buildings is fundamental to improving cooling energy efficiency.
Tahat, M. A. et al., Int. J. Energy Research, Sep. 1995, 19, (7) 603-613. The feasibility of employing activated alumina and water, as reversible reaction pairs, in an integrated thermochemical heat-pump/energy-store has been studied theoretically and experimentally. The use of such a heat pum for the provision of heating and cooling applications has been investigate If. With the activated alumina absorbing water by up to 45 +/- 1% of the dry alumina’s weight, a heat of adsorption of 2.92 +/- 0.1 MJ/kg of water has been achieved.
0 tlmlzatlon of the speclflc rats of refrigeration In 95166453 combined refrPgeratlon cycles Chen, L. et al., Energy, Oct. 1995, 20, (lo), 1049-1053. The optimization problem of a combined refrigeration cycle formed by two endoreversible Carnot refrigeration cycles m series without intermediate reservoirs has been studied using finite-time thermodynamics. The fundamental relation between cooling quantity and coefficient of erformance (COP) of the combined cycle is derived for a general physica Ymodel of a combined c cle. Relations are derived between the SROR (=optimal specific rate otyrefrigeration, i.e. the average rate of refrigeration per unit of total heat-transfer surface area) and the COP for a piston-type, stable flow model of combined cycles. The results may be extended to an endoreversible, combined refrigeration cycle formed by more than two endoreversible Carnot refrigeration cycles.
Enhanced nucleate boiling surfaces are currently used in refrigeration and orocess heat exchanaers. Enhanced boilinn surfaces offer ootential for other applications, i&ding cooling of elec;onic equi ment. ?‘he possibility that the performance of such enhanced boiling su Kaces may be further improved by surface oxidation is addressed in this work. Ahhough the mechanism is not fully understood the current results suggest an important industrial application. The paper describes an apparatus and procedures for expanding the current limited data base for the performance of enhanced surface in pool boiling. The results of this study and the related methodology should help others address key issues of the surface geometry, oxidation, roughness and contact angle effects on nucleate pool boiling.
95106459 Pool bolllng of R-11 refrigerant and water on oxldlzed enhanced tubes irnndIo&mu, H. E. et al., J. of Enhanced Heat Transfer, 1995, 2, (3), -
.
15 ENVIRONMENT 95106454 An overview of chlorine-free refrigerants for centrifugal chillers Goktun, S. Energy, Sep. 1995, 20, (9) 937-940. Criteria are described for ideal working substances in centrifugal chillers. Chlorine-free fluorinated ethers and hydrocarbons are being considered as potential replacement for R-11, R-12 and R-114. Corn arisons are made in terms of ecological and thermophysical properties anx standard air-conditioning parameters for working substances which can be used without change of system design. R-245ca and E245fa are promising alternatives to R-11 for the low-capacity range, and R-134a is the best retrofit refrigerant for R-12 in the medium-capactty range. R-236ea, R-236ca? R-236fa, R236cb, and E-134 are promising refrigerants for replacmg R-114 in centrifugal chillers for the high-capacity range.
456
Fuel and Energy Abstracts November 1995
Pollution,
Health Protection,
Safety
95lO6460 Activated coke technology for flue gss clsanlng In waste and special waste lnclnsratlon plants Cleve,U. Brennst.-Waerme-KraF, 1994, 46, (lo), V25-37. (In German) Discusses the various cleaning technologies for flue gases from waste and special waste incinerators, including safeguards, and experiences of activated coke technology. Reports on the spent activated coke disposal by desorption or combustion.