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04164 Thermodynamic optimization of the thermal process in energy storage using multiple phase change materials
13
Space heating and cooling
Clapeyron equation and optimizing by vapour pressure data. Included in the enthalpy-concentration chart were results of estimation using experimental data on the vapour pressure of refrigerant/absorbent mixtures. The method used here was based on the theory of activity coefficient. A UNIQUAC model was applied for determining the correlation between coefficients. With these two charts, it is possible to accurately and quantitatively evaluate the characteristics of potential working fluids of absorption type refrigeration machines. Practical experiences with IR-controlled supply 98104156 terminals in dwellings and offices Ducarme, D. et al. Energy and Buildings, 1998, 27, (3), 275-282. In order to achieve good indoor air quality, ventilation is necessary, but can be a major energy consumer. Results from two experimental studies carried out in several dwellings and office buildings show that the use of presence detection (infrared sensor) for controlling ventilation has a potential for substantial reductions in the heating energy consumption. A simulation study of the impact of infrared spectroscopy (IR) controlled ventilation on the yearly heating energy consumption was performed and it showed that reductions from 27% to 47% can be obtained in well insulated office buildings. Pricing residential load shedding as a call option 96104157 Geiss, C. G. Energy, 1998, 23, (4) 309-316. Simulated air-conditioner power-interruption programmes are shown to reduce the peaks of a utility load profile. The value of this load-shifting capability is determined by a financial call option pricing model. The airconditioner interruption option is determined to be worth about $0.65 per summer month to a representative utility; but this value varies widely with costs, volatility of demand, and the skill of implementation by utility managers. The interruption option is given an imputed value derived from the share prices of the utility. This imputed value approximates the value obtained by simulation. A reaction calorimeter with compensation heater 96/04156 and differential cooling Schlegel, M. and Lowe, A. Chemical Engineering and Processing, 1998, 37, (l), 61-67. The paper describes an attempt to combine and improve the advantages of different types of reaction calorimeters pursuing the main objectives of simple design and simple data treatment. Operated in the so-called heatbalance mode, the calorimeter features a jacket that can be operated as a once-through differential cooler at high flow rates. Modern methods of measurement, control and signal processing have been applied to solve the problem of accurately measuring differential temperatures of 0.1 K or below. A second new advantage is the strictly isothermal operation of both the reactor, by means of a compensation heater, and the jacket, through separate control loops. ‘Strictly isothermal’ means that the accumulation terms in the heat balances with their ill-defined heat capacities can safely be neglected and error-amplifying differentiation of sampled temperature data be avoided. Also described are some experimental runs to test the performance of this calorimeter. 96/04159 refrigeration
Refrigerant for carbon dioxide liquefaction or apparatus utilizing latent heat of liquefied natural
!!ikado, Y. et al. Jpn. Kokai Tokkyo Koho JP 09,279,132 [97,279,132] (Cl. CO9K5/04), 28 Ott 1997, Appl. 96/94,428, 16 Apr 1996, 5 pp. (In Japanese) Residential mechanical ventilation Systems: per96104160 formance criteria and evaluations Dorer, V. and Breer, D. Energy and Buildings, 1998, 27, (3), 247-255. Either as part of either a Swiss research or a P&D (pilot and demonstration) project, the performance of mechanical ventilation systems has been checked in several innovative residential houses. This paper gives a list of performance criteria for the ongoing comparison and evaluation of these mechanical ventilation systems. For some criteria, target values are proposed. In the second part, this paper briefly describes four residential buildings with mechanical ventilation systems where such evaluations were performed, and highlights interesting design features and results from the measurements. It then focuses on discrepancies between the design goals and what has been encountered in reality during the evaluation campaign. Problem items were, among others, commissioning, occupant acceptance and window opening behaviour as well as sealing of ducts and heat exchangers. Saturated liquid thermal conductivity correlations 9BlQ4161 for some new refrigerants Srinivasan, K. and Oellrich, L. R. Int. 1. Energy Res., 1998, 22, (6), 579590. A set of linear equations describing the temperature dependence of the saturated liquid thermal conductivity covering the region of engineering importance for the new hydrofluorocarbons (HFC) 32, 125, 134a, 143a, 152a and hydrochlorofluorocarbons (HCFC) 123, 124, 141b and 142b, is presented. Available experimental data in the literature have been considered to arrive at a correlation of the form X = A - BT. It is observed that there exists an appreciable discrepancy between various
388
Fuel and Energy Abstracts
September
1996
sources of data in spite of the same purity of samples used and the same measurement technique being adopted. The correlations obtained here could be useful in engineering design applications. 98/04162 Summer cooling with night ventilation for office buildings in moderate climates Kolokotroni, M. et al. Enera and Buildings, 1998, 27, (3), 231-237. In order to assess the suitability of night ventilation for cooling offices in moderate climates such as that of the UK, plots of summer weather data were presented on the bioclimatic chart for three locations within the country. Most of the external weather conditions were found to lie within the thermal mass and ventilation effectiveness areas of the charts. To confirm this, thermal simulations of a typical office module under a variety of internal conditions and summer weather data were performed. Predictions have shown that internal temperatures can be maintained below the external values for solar and internal gains of up to about 50 Wi m2 of the conditioned floor area. Field measurements in a refurbished office have confirmed that temperatures in night-ventilated spaces are generally lower during the following day, especially during the early hours of the working day. Finally, the development of a pre-design tool in the context of IEA Annex 28 on ‘Low-Energy Cooling Systems’ is discussed. The main aim of the tool is to increase the awareness of designers for the energy benefits and the range of parameters for the application of night ventilation as the first means of cooling, so that the need for artificial cooling is minimized or avoided altogether. Thermodynamic analyses of the performance of a 96lQ4163 thermal-storage system with water as its working fluid Chen, G. M. et al. Appl. Energy, 1997, 57, (4). 263-270. A proposal is put fonvard for a thermal storage system for air-conditioning with water as its working substance. The system has no environmental problems, owing to the use of water, a natural substance. The system consists of a steam compressor, a condenser, an expansion valve, a separator, two ejectors, an evaporator and a pump. The pump and ejectors mean the compression ratio and the swept volume of the compressor are much smaller than those of a traditional system at lower evaporation temperatures. The new system can be applied to ordinary air-conditioning, thermal storage or both. A numerical simulation was conducted to analyse the characteristics of the system under different working conditions, and traditional systems using water or R22 as the working medium were used for comparison. 98/04164 Thermodynamic optimization of the thermal process in energy storage using multiple phase change materials Gong, Z.-X. and Mujumdar, A. S. Appl. Therm. Eng., 1997, 17, (11) 10671083. A thermodynamic analysis of the energy charge/discharge processes in a latent heat thermal storage system using multiple phase change materials (PCMs) has been conducted. The basis for this analysis was a lumped model for the PCMs which assumes that a PCM is a thermal reservoir with a constant temperature of its melting point and a distributed model for the heat transfer fluid which assumes that the temperature of the fluid varies in its flow path. Thermal storage systems using two, three and five PCMs were analysed. The results show that the exergy efficiency can be dramatically enhanced using multiple PCMs compared with a single PCM. Illustrative results are presented and discussed in terms of their potential applications in efficient thermal storage devices. Thermodynamic properties of R 134, R 134-R 134a 9BlQ4165 and R 134-R22 Song, X. et al. Gaoxiao Huaxue Gongcheng Xuebao 1997, 11, (3) 238-243. (In Chinese) A comparison is made of some thermodynamic properties of refrigerants R 134, R 134-R 134a and R 134-R22 obtained, based on the Martin-Hou equation and other calculation formula. There are thermodynamic tables and charts of R 134 in the paper. A theoretical basis for R 134 application in refrigerating industry is provided by the data. Thermodynamic properties of two ternary refriger96i64166 ant mixtures-measurements and equations of state Kleemiss, M. Forrschr.-Ber. VDI, Reihe 19, 1997, 98, 1-151. (In German) For refrigerant mixtures R-134a/R-125/R-32 and R-134a/R-143alR-125 and for five binary limiting cases, the thermodynamic property data are tabulated. Measurement is described of liquid density, gas density, and phase equilibrium properties. An equation of state is provided for calculation of thermodynamic properties in similar concentration ranges. Calculations are shown for mixing volumes. 9BlO4167 Utilization of waste heat from the kitchen furnace of an enclosed campus Alkhamis, T. M. et al. Energy Cowers. Mgmt, 1998, 39, (lo), 1113-1119. This research aims to study the potential sources of waste heat recovery at the enclosed campus of Mu’tah University. Based on certain criteria, the kitchen of the students’ club was identified as a good source of waste heat recovery. A coil heat exchanger was designed, manufactured, installed and analysed to utilize the sensible heat contained in the exhaust gas stream out of the kitchen furnace. The research results indicate that over 60% of the kitchen furnace waste heat can be recovered and that the investment in such coil heat exchanger system is highly economical.
Space heating and cooling
Clapeyron equation and optimizing by vapour pressure data. Included in the enthalpy-concentration chart were results of estimation using experimental data on the vapour pressure of refrigerant/absorbent mixtures. The method used here was based on the theory of activity coefficient. A UNIQUAC model was applied for determining the correlation between coefficients. With these two charts, it is possible to accurately and quantitatively evaluate the characteristics of potential working fluids of absorption type refrigeration machines. Practical experiences with IR-controlled supply 98104156 terminals in dwellings and offices Ducarme, D. et al. Energy and Buildings, 1998, 27, (3), 275-282. In order to achieve good indoor air quality, ventilation is necessary, but can be a major energy consumer. Results from two experimental studies carried out in several dwellings and office buildings show that the use of presence detection (infrared sensor) for controlling ventilation has a potential for substantial reductions in the heating energy consumption. A simulation study of the impact of infrared spectroscopy (IR) controlled ventilation on the yearly heating energy consumption was performed and it showed that reductions from 27% to 47% can be obtained in well insulated office buildings. Pricing residential load shedding as a call option 96104157 Geiss, C. G. Energy, 1998, 23, (4) 309-316. Simulated air-conditioner power-interruption programmes are shown to reduce the peaks of a utility load profile. The value of this load-shifting capability is determined by a financial call option pricing model. The airconditioner interruption option is determined to be worth about $0.65 per summer month to a representative utility; but this value varies widely with costs, volatility of demand, and the skill of implementation by utility managers. The interruption option is given an imputed value derived from the share prices of the utility. This imputed value approximates the value obtained by simulation. A reaction calorimeter with compensation heater 96/04156 and differential cooling Schlegel, M. and Lowe, A. Chemical Engineering and Processing, 1998, 37, (l), 61-67. The paper describes an attempt to combine and improve the advantages of different types of reaction calorimeters pursuing the main objectives of simple design and simple data treatment. Operated in the so-called heatbalance mode, the calorimeter features a jacket that can be operated as a once-through differential cooler at high flow rates. Modern methods of measurement, control and signal processing have been applied to solve the problem of accurately measuring differential temperatures of 0.1 K or below. A second new advantage is the strictly isothermal operation of both the reactor, by means of a compensation heater, and the jacket, through separate control loops. ‘Strictly isothermal’ means that the accumulation terms in the heat balances with their ill-defined heat capacities can safely be neglected and error-amplifying differentiation of sampled temperature data be avoided. Also described are some experimental runs to test the performance of this calorimeter. 96/04159 refrigeration
Refrigerant for carbon dioxide liquefaction or apparatus utilizing latent heat of liquefied natural
!!ikado, Y. et al. Jpn. Kokai Tokkyo Koho JP 09,279,132 [97,279,132] (Cl. CO9K5/04), 28 Ott 1997, Appl. 96/94,428, 16 Apr 1996, 5 pp. (In Japanese) Residential mechanical ventilation Systems: per96104160 formance criteria and evaluations Dorer, V. and Breer, D. Energy and Buildings, 1998, 27, (3), 247-255. Either as part of either a Swiss research or a P&D (pilot and demonstration) project, the performance of mechanical ventilation systems has been checked in several innovative residential houses. This paper gives a list of performance criteria for the ongoing comparison and evaluation of these mechanical ventilation systems. For some criteria, target values are proposed. In the second part, this paper briefly describes four residential buildings with mechanical ventilation systems where such evaluations were performed, and highlights interesting design features and results from the measurements. It then focuses on discrepancies between the design goals and what has been encountered in reality during the evaluation campaign. Problem items were, among others, commissioning, occupant acceptance and window opening behaviour as well as sealing of ducts and heat exchangers. Saturated liquid thermal conductivity correlations 9BlQ4161 for some new refrigerants Srinivasan, K. and Oellrich, L. R. Int. 1. Energy Res., 1998, 22, (6), 579590. A set of linear equations describing the temperature dependence of the saturated liquid thermal conductivity covering the region of engineering importance for the new hydrofluorocarbons (HFC) 32, 125, 134a, 143a, 152a and hydrochlorofluorocarbons (HCFC) 123, 124, 141b and 142b, is presented. Available experimental data in the literature have been considered to arrive at a correlation of the form X = A - BT. It is observed that there exists an appreciable discrepancy between various
388
Fuel and Energy Abstracts
September
1996
sources of data in spite of the same purity of samples used and the same measurement technique being adopted. The correlations obtained here could be useful in engineering design applications. 98/04162 Summer cooling with night ventilation for office buildings in moderate climates Kolokotroni, M. et al. Enera and Buildings, 1998, 27, (3), 231-237. In order to assess the suitability of night ventilation for cooling offices in moderate climates such as that of the UK, plots of summer weather data were presented on the bioclimatic chart for three locations within the country. Most of the external weather conditions were found to lie within the thermal mass and ventilation effectiveness areas of the charts. To confirm this, thermal simulations of a typical office module under a variety of internal conditions and summer weather data were performed. Predictions have shown that internal temperatures can be maintained below the external values for solar and internal gains of up to about 50 Wi m2 of the conditioned floor area. Field measurements in a refurbished office have confirmed that temperatures in night-ventilated spaces are generally lower during the following day, especially during the early hours of the working day. Finally, the development of a pre-design tool in the context of IEA Annex 28 on ‘Low-Energy Cooling Systems’ is discussed. The main aim of the tool is to increase the awareness of designers for the energy benefits and the range of parameters for the application of night ventilation as the first means of cooling, so that the need for artificial cooling is minimized or avoided altogether. Thermodynamic analyses of the performance of a 96lQ4163 thermal-storage system with water as its working fluid Chen, G. M. et al. Appl. Energy, 1997, 57, (4). 263-270. A proposal is put fonvard for a thermal storage system for air-conditioning with water as its working substance. The system has no environmental problems, owing to the use of water, a natural substance. The system consists of a steam compressor, a condenser, an expansion valve, a separator, two ejectors, an evaporator and a pump. The pump and ejectors mean the compression ratio and the swept volume of the compressor are much smaller than those of a traditional system at lower evaporation temperatures. The new system can be applied to ordinary air-conditioning, thermal storage or both. A numerical simulation was conducted to analyse the characteristics of the system under different working conditions, and traditional systems using water or R22 as the working medium were used for comparison. 98/04164 Thermodynamic optimization of the thermal process in energy storage using multiple phase change materials Gong, Z.-X. and Mujumdar, A. S. Appl. Therm. Eng., 1997, 17, (11) 10671083. A thermodynamic analysis of the energy charge/discharge processes in a latent heat thermal storage system using multiple phase change materials (PCMs) has been conducted. The basis for this analysis was a lumped model for the PCMs which assumes that a PCM is a thermal reservoir with a constant temperature of its melting point and a distributed model for the heat transfer fluid which assumes that the temperature of the fluid varies in its flow path. Thermal storage systems using two, three and five PCMs were analysed. The results show that the exergy efficiency can be dramatically enhanced using multiple PCMs compared with a single PCM. Illustrative results are presented and discussed in terms of their potential applications in efficient thermal storage devices. Thermodynamic properties of R 134, R 134-R 134a 9BlQ4165 and R 134-R22 Song, X. et al. Gaoxiao Huaxue Gongcheng Xuebao 1997, 11, (3) 238-243. (In Chinese) A comparison is made of some thermodynamic properties of refrigerants R 134, R 134-R 134a and R 134-R22 obtained, based on the Martin-Hou equation and other calculation formula. There are thermodynamic tables and charts of R 134 in the paper. A theoretical basis for R 134 application in refrigerating industry is provided by the data. Thermodynamic properties of two ternary refriger96i64166 ant mixtures-measurements and equations of state Kleemiss, M. Forrschr.-Ber. VDI, Reihe 19, 1997, 98, 1-151. (In German) For refrigerant mixtures R-134a/R-125/R-32 and R-134a/R-143alR-125 and for five binary limiting cases, the thermodynamic property data are tabulated. Measurement is described of liquid density, gas density, and phase equilibrium properties. An equation of state is provided for calculation of thermodynamic properties in similar concentration ranges. Calculations are shown for mixing volumes. 9BlO4167 Utilization of waste heat from the kitchen furnace of an enclosed campus Alkhamis, T. M. et al. Energy Cowers. Mgmt, 1998, 39, (lo), 1113-1119. This research aims to study the potential sources of waste heat recovery at the enclosed campus of Mu’tah University. Based on certain criteria, the kitchen of the students’ club was identified as a good source of waste heat recovery. A coil heat exchanger was designed, manufactured, installed and analysed to utilize the sensible heat contained in the exhaust gas stream out of the kitchen furnace. The research results indicate that over 60% of the kitchen furnace waste heat can be recovered and that the investment in such coil heat exchanger system is highly economical.