ISSN:0363-907X    

DOI:10.1002/er.4440090402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper presents a thoermodynamic assessment of two stage absorption refrigeration and air‐conditioning systems. Two working fluids, namely water‐LiBr and NH3‐H2O as refrigerant‐absorbent combinations have been considered for the production of different cooling temperatures. Both the systems are assumed to be operated with hot water available from solar collectors. Thermal modelling and a parametric study of a two stage absorption system, based on thermodynamic analysis aided by computer, have been carried out in detail. It is found that the cascading of two stage absorption systems (in which the first stage evaporator produces cooling water to be circulated in the absorber of the second stage) can be easily operated to produce much lower temperatures suitable for refrigeration and air‐conditioning applications. The COP of a two stage absorption system is lower than that of a single stage; however, the second stage can be operated with lower generator temperatures than the first stage. However, there is an advantage for a two stage system because of the slow fall‐off in COP at higher generator t

ISSN:0363-907X    

DOI:10.1002/er.4440090403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe energy saving obtainable with active solar heating and heat pumps has been studied for several years in the Northern climate of Finland. The studies deal mainly with small houses. A computer program is developed which calculates hour by hour the annual energy balance of different heating systems. The performance, of the heating systems are also measured in inhabited houses.The calculations show that the useful solar energy obtainable from the collector is 50–400 kWh/m2annually depending on the system and the collector size. A heat pump in the system is very advantageous, because it keeps the heat losses low and the collector efficiency high. It approximately doubles the energy obtainable. The measurement results have not been as good as expected. The solar energy obtained from the collector has been 120–160 kWh/m2annually. The main reasons for the low solar energy are design and equipment faults and the shading effects.The best energy saving device is the earth heat pump. It is also therefore very advantageous that the peak power demand decreases markedly. When the area of the earth pipes is large enough, energy may be extracted from earth through the whole year. The annual coefficient of performance is 2–3. Also a heat pump which extracts heat from exhaust air in dwelling houses has been very prom

ISSN:0363-907X    

DOI:10.1002/er.4440090404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe decrease in the yield of biogas in winter months in the usual systems—fixed dome and floating dome types—can be checked by providing insulation on the inner surface of the gas holder. A mathematical model has been developed to study the effect of putting in such insulation. A novel concept of making a shallow solar pond water heater over the gas holder to reduce the heat losses and simultaneously provide water for hot charging is proposed and analysed. Calculations corresponding to a typical winter day at New Delhi have been made for a numerical appreciation of the developed analy

ISSN:0363-907X    

DOI:10.1002/er.4440090405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA behavioural study by Brundrett in 1977 indicated that in the U.K. a substantial number of persons slept with their bedroom windows open. Such a habit, if it prevailed during cold weather, could lead to considerable energy losses. However Brundrett's sample was small and the data, which were gathered in the summer, might reflect behaviour which varied with the seasons and so were biased. The present investigation questioned a larger sample during the winter. The questionnaire also invited respondents to cite the ill‐effects from which they might suffer if their bedroom window were closed all night. The results generally confirmed Brundrett's indications regarding the prevalence of window opening. The reasons for it appear to be related to beliefs regarding ventilation and health. These could have their origins in the writings of Florence Nightingal

ISSN:0363-907X    

DOI:10.1002/er.4440090406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractAn experimental study was conducted in Thailand to determine the thermal performance of twin glazed windows with dynamic insulation. The effects of blinds situated either between or outside the glazing were analysed. With an external blind, the heat transfer coefficient was 1–25 W/m2°C with natural convection and 0–6 W/m2°C for a flow of 20m3/h (glass area = 2–16m2).The solar flux transmitted was evaluated analytically and experimentally depending on the blind's position. An economic study was performed on a six‐sotrey air‐conditioned building in Thailand. It showed in tropical countries that it may be more economical to use air flow windows than to have tinted single or double gl

ISSN:0363-907X    

DOI:10.1002/er.4440090407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe exothermic reaction of acetaldehyde and methyl alcohol is suggested as a candidate for energy transport and upgrading. A temperature rise of up to 50°C could be obtained for this system. A lower heat source could also be upgraded by using two distillation columns working at different pressures; thus a low level heat source at 60°C could be delivered to a consumer centre at 70°C by this meth

ISSN:0363-907X    

DOI:10.1002/er.4440090408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA thermal analysis has been made of a number of viable solar systems, namely (i) a solar canopy, (ii) a shallow solar pond (SSP) water heater, (iii) insulation and (iv) an SSP with a solar canopy around the digester, to boost the biogas production in conventional KVIC biogas plants during the winter months. Numerical calculations for a typical sunny winter day (17 January 1984) in the climate of New Delhi show that an SSP water heater on the top of the gas holder, covered with a solar canopy, is a good option from thermal point of view.

ISSN:0363-907X    

DOI:10.1002/er.4440090409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractIn the present communication, the kinetics of diffusion of salt in a stacked layer solar pond has been investigated by using the step function for the initial state of salt distribution and a closed form solution for the salt concentration has been obtained with the boundary conditions of an operational solar pond. It has been predicted that the time required for a two layered solar pond with non‐convective zone of about 1 m depth to reach equilibrium concentration gradient is about 585 days, whereas that required for a ten layered pond is only 96 day

ISSN:0363-907X    

DOI:10.1002/er.4440090410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA simple pressure calibrator is described which is suitable for the routine on‐line calibration of pressure transducers in automatically recording data‐logging systems. The calibrator is based on a beam balance approach, and steps have been taken to ensure the stability of the system and the reproducibility of the resu

ISSN:0363-907X    

DOI:10.1002/er.4440090411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY