摘要:

AbstractIn this paper we discuss an inexpensive solar collector in which the heat storage material is sand or sand mixed with iron filings. The heat is absorbed by the blackened portion of the heat storage material. The heat is withdrawn from the system by water flowing through a network of plastic pipes buried in the heat storage material at an appropriate depth. The large efficiency is obtained when the material is sand mixed with iron filings. It is shown that the efficiency of the system can be judged from the glass cover temperature. As the glass cover temperature decreases, the efficiency of the system increases.

ISSN:0363-907X    

DOI:10.1002/er.4440060102

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

年代:1982

数据来源: WILEY

摘要:

AbstractThis paper presents an analytical study of a stationary plane mirror solar concentrator. It is composed of an array of East‐West oriented trapezoidal channels with two sided reflecting walls and a tubular absorber as a receiver at the base. We have analysed and identified the most practical design parameters for a trough like concentrator. The one‐ and two‐faceted plane side wall configurations with tubular receiver at the base of the trough have been studied in detail. It has been concluded that large savings in reflecting surfaces are possible while sacrificing some reduction in concentration. A theoretical prediction for the dependance of absorber efficiency on temperature has been obt

ISSN:0363-907X    

DOI:10.1002/er.4440060103

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe paper deals with the results of preliminary studies on the effect of surface area on the performance of a solar still. Results on the effects of floating coal, compartmentalization and stirring of raw water are reported with respect to a reference still in terms of percentage increase in distillate output. The results show an increase in distillate output in all these cases especially at low water depths and in the presence of solar radiation. The stirring of raw water gave interesting results during daytime which have been explained on the basis of increased aquation of air within the system.

ISSN:0363-907X    

DOI:10.1002/er.4440060104

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

年代:1982

数据来源: WILEY

摘要:

AbstractAn analysis of the oscillatory MHD channel flow of an electrically conducting, viscous, incompressible fluid under a transverse magnetic field is presented. The transient velocity and the transient temperature are exhibited graphically, whereas the numerical values of the amplitude, phase of the skin‐friction and the first and second harmonics of the rate of heat transfer are displayed in tabular form. Also discussed are the effects ofM(the Hartmann number),e(the loading parameter), ω* (the frequency), andE(the Eckert numbe

ISSN:0363-907X    

DOI:10.1002/er.4440060105

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

年代:1982

数据来源: WILEY

摘要:

AbstractFollowing a simplified approach, we derive an expression for the gas‐dynamic voltage drop in a finitely segmented Faraday‐type combustion MHD generator, taking into account the non‐uniform Hall parameter across the channel. Combining the electrical sheath voltage drop, discussed briefly, with the gas‐dynamic voltage drop, the effect of a non‐uniform Hall parameter on the electrode voltage drop is studied using the theoretical and experimental input parameters of the Indian MHD channel test. The condition for the validity of the usual assumption of uniform Hall parameter across the channel is pointed out. Analysis of the measured electrode voltage drop predicts the real gas conductivity in the core to be in the range of 60 to 75 per cent of the theoretically calculated core con

ISSN:0363-907X    

DOI:10.1002/er.4440060106

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

年代:1982

数据来源: WILEY

摘要:

AbstractDecision making under uncertainty is a further step in comparison with decision under risk in the more realistic approach to decision problems concerning, for instance, nuclear power system development. In this paper the theory developed is, however, based in a great measure on that of risk preference. The theory of decision making under uncertainty is applied to a nuclear power system NPS consisting of PHWRs and PWRs integrated with LMFBRs. Nine development alternatives of the system which evolves for a period of 40 years are considered. The fast reactor integration is accomplished beginning in year 15 with a variable time delay so that for every alternative, six final states are possible. An econometric model of the system offers the cost price of annual energy generated by the system at the end of the given time interval for every possible state of any alternative. Further, the complete ignorance case is considered, resulting from the principle of insufficient reason, and the risk preference theory is applied. Then the partial ignorance case is taken into account and finally it it shown how we can infer a plausible apriorioptimal probability distribution to have an optimal decision characterized by an optimal selected development alternative, for which a minimum certain equivalent of cost price of annual energy is realized with an accepted level of risk and a determined value of risk averter.

ISSN:0363-907X    

DOI:10.1002/er.4440060107

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

年代:1982

数据来源: WILEY

摘要:

AbstractThermochemical energy conversion is analysed on a thermodynamic basis with particular interest in obtaining guidance as to solar thermochemical absorber design at an early stage of development when technical and cost information is often unreliable. An earlier‐used thermodynamic equivalence technique which is equally applicable to both the endothermic and exothermic reactions has been developed to the point where it gives a clear insight into all sources of heat and work. The method is applied in particular to separating endothermic reactions of which ammonia dissociation is a prime example. A reversibility ratio is defined as the ratio of irreversible to reversible work and it is shown that in a practical solar thermochemical absorber design the reversibility ratio should be minimized, corresponding to reaction temperature minimization and therefore to tower energy losses and to potential for use of lower cost reactor materials and more active catalysts. Values of reversibility ratio are calculated for the ammonia system and are discussed in relation to solar thermochemical absorber design. In a final analysis employing the thermodynamic equivalence technique, it is shown that the apparent paradox between liquid and alternative gas pump work requirements in a liquid/gas thermochemical system is thermodynamically consistent with the internal generation of effective work from the heat source used to drive the endothermic reaction syste

ISSN:0363-907X    

DOI:10.1002/er.4440060108

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

年代:1982

数据来源: WILEY

摘要:

AbstractA portable solar conical concentrator of 1 metre aperture and consisting of 63 triangular plane mirror strips has been designed and fabricated. This device has been tested using cylindrical receivers having radii of 7.5 cm and 3 cm, respectively. It required 2 h for 8 kg of water in a large cylinder to reach boiling point, whereas it required only 20 min for 1.25 kg of water to boil in a smaller cylinder. The steam formed can be utilized to sterilize medical instruments or for other purposes as desired. The paper includes a detailed analytical treatment of heat exchange at the surface of the absorber, an evaluation of the appropriate heat transfer coefficients, and solutions of the energy balance equation for cylindrical absorbers of the sizes noted. Efficiencies as high as 60 per cent have been observed.

ISSN:0363-907X    

DOI:10.1002/er.4440060109

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

年代:1982

数据来源: WILEY

摘要:

AbstractA computer model is developed to simulate the performance of air‐to‐water heat pumps heating a house via a radiator system. The performance characteristics of the heat pumps are derived from laboratory measurements. Hourly weather observations are used to calculate the heat demand of the house and the performance of the heat pump. The effects of changes in heat pump characteristics, changes of radiator size, and changes in heat demand of the house due to insulation, are compared in terms of their effects on annual energy consumpt

ISSN:0363-907X    

DOI:10.1002/er.4440060110

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

年代:1982

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440060111

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

年代:1982

数据来源: WILEY