摘要:

AbstractThis review article presents an account of several investigations of heat and mass transfer in the field of magnetohydrodynamics which have been carried out during the last few years by several authors. If an article has been omitted, it is entirely by oversight and not by intention.

ISSN:0363-907X    

DOI:10.1002/er.4440150902

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

年代:1991

数据来源: WILEY

摘要:

AbstractSpray‐pyrolysed selective cobalt‐oxide (CoOx) coatings were prepared on the surface of a bright nickel‐plated copper tubular absorber (α = 0.89–0.91 and ϵ100°C= 0.18) for operation in conjunction with a prototype linear Fresnel reflector solar concentrator (LFRSC). Some preliminary tests were conducted to study the optical and thermal performance characteristics of the selective cobalt‐oxide coated absorber in the concentrated solar flux. The tests conducted included determination of the overall heat loss coefficientULof the absorber at temperatures from 50 to ∼ 120°C, and the optical efficiency ηoof the concentrator‐absorber system, and measurement of the stagnation temperature of the absorber with the prototype solar concentrator. Based on the results ofULand ηomeasurements, the thermal efficiency η of the concentrator‐absorber system at a working temperature of 115°C has been determined for a typical beam radiationIbof 600 W/m2. Further, comparison of the results of this study with those obtained using a dimensionally identical black‐painted absorber indicates that the performance of the selective cobalt‐oxide coated absorber is considerably superior to that of an ordi

ISSN:0363-907X    

DOI:10.1002/er.4440150903

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe paper describes the calculation of the beam solar radiation transmission across the uniform salinity upper convecting zone (UCZ) and the salinity stratified gradient zone (GZ), when the extinction coefficient is not only wavelength but also salinity‐concentration dependent, assuming that the effect of scattering to be negligible. The results are useful in determining the effects of dissolved salt ions on pure water transmission, at least according to the existing measured data in the literatur

ISSN:0363-907X    

DOI:10.1002/er.4440150904

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe paper describes the experimental development of an alternative regenerative refrigeration cycle. The cycle attempts to overcome the inefficiencies caused by flash gas entering the evaporator by a novel use of the main compressor. The system incorporates an extra vessel in place of the traditional expansion valve. The vessel is filled with high temperature, high pressure refrigerant from the condenser. The compressor is then switched from the evaporator, thus reducing the pressure. As the pressure is lowered, it is hoped that the flash gas is removed. The cycle is compared, both theoretically and practically, with the standard vapour compression cycle. The problems encountered and their solutions are also presented were possible.

ISSN:0363-907X    

DOI:10.1002/er.4440150905

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe thermal performance of a building fitted with an evaporative cooling tower has been evaluated in terms of discomfort index for two climates, namely, composite and hot‐dry, typified by New Delhi and Jodhpur, respectively. The effects of various evaporative cooling parameters (height and cross‐sectional area of the tower, packing factor, area of the pads, resistance offered to the air flow and local wind conditions) on the performance of the building have been analysed. It was found that, for given parameters of the tower and wind conditions, there is an optimum height of the tower for which the thermal discomfort condition in the building is minimum. The optimum values of the tower height for comfort conditions in the building for various other tower parameters have been obtained for each clim

ISSN:0363-907X    

DOI:10.1002/er.4440150906

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe paper outlines a simple method of obtaining a Bambach style formula for R22/paraffinic oil mixtures. The method could be applied for any refrigerant/oil mixture. The formula for R22/oil mixtures is presented.

ISSN:0363-907X    

DOI:10.1002/er.4440150907

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

年代:1991

数据来源: WILEY

摘要:

AbstractA mathematical model has been developed to predict the thermal performance of ann‐effect diffusion still which uses a flat‐plate solar collector as well as a conventional source as heat generator. The model is based on the numerical solution of various differential equations, and yields temperature ditributions in the direction of the feed flow. The model is validated against the experimental results of Elsayedet al.(1984) for a three‐effect still. In order to appreciate the model, numerical calculations have been made for studying the effect of different design/operational parameters on the performance of a three‐effect still. Results of the calculations show that a three‐effect still using a flat‐plate solar collector as the heat‐source produces a considerably higher distillate output in a climate corresponding to that of Delhi, India, then does a single‐effect basin t

ISSN:0363-907X    

DOI:10.1002/er.4440150908

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

年代:1991

数据来源: WILEY

摘要:

AbstractCooling loads during the peak period can be reduced if a building is subcooled a few degrees below its normal thermostat set‐point during the preceding night. During the day the thermostat must control the warm‐up in such a way that the stored energy is released when it brings maximum benefit. This strategy exploits the heat capacity of the building itself; it can be implemented at low cost and without sacrifice of comfort. To evaluate the strategy for a given building and to control the thermostat, one needs to know the thermal behaviour of the building. Building temperature, internal load and solar data are used to determine a small number of thermal parameters which characterize the building. Several thermostat control strategies, distinguished by their knowledge of the building dynamics, are described and simulated, with a data‐based dynamic model. Universal graphs for effective storage capacity and storage efficiency are developed. A simple economic analysis shows that subcooling is likely to be cost‐effective for many commercial buildings, with current electric rate sc

ISSN:0363-907X    

DOI:10.1002/er.4440150909

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

年代:1991

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440150910

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

年代:1991

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440150901

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

年代:1991

数据来源: WILEY