摘要:

AbstractA finite‐difference solution for unsteady free‐convection flow, taking into account mass‐transfer effects, is presented here. The concentrations of species, such as H, He, H2O, NH3, CO2are considered. The transient velocity, the transient temperature and the transient concentration profiles are shown on graphs. Also, the average and local Nusselt number, Sherwood number and skin‐friction are shown on graphs. The effects ofGr(Grashoff number) andSc(Schmidt number) for a fixed value ofN(buoyancy ratio parameter) are discussed. The stability and convergence of the implicit finite‐difference scheme are also es

ISSN:0363-907X    

DOI:10.1002/er.4440090102

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

年代:1985

数据来源: WILEY

摘要:

AbstractThree types of no‐salt solar ponds, which do not exhibit environmental or operational problems of the kind observed for salt ponds, are examined on a laboratory scale. The negative temperature gradient necessary for heat storage was obtained by using appropriate arrangements in such a way that narrow passages appear which reduce substantially the heated water currents, or by using two (or more) transparent immiscible liquids which constitute a density gradient serving the same purpose. The influence of the dissolved air in the water mass is discusse

ISSN:0363-907X    

DOI:10.1002/er.4440090103

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

年代:1985

数据来源: WILEY

摘要:

AbstractThis investigation reports a new type of solar water heating system without water pipes on the collector surface or a separate storage tank. The water to be heated continuously flows perpendicularly from an upper transparent cover to a porous absorber and is stored in a small volume beneath this assembly. Three different systems were designed, manufactured and tested but only one proved to be successful; this design indicated higher thermal efficiency compared to conventional collectors at high flow rates whereas at low flow rates the opposite is true.

ISSN:0363-907X    

DOI:10.1002/er.4440090104

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn Italy solar thermal energy and energy from biogas are two possible means of reducing dependence on energy imports. Using a multiperiod LP model (MARKAL) the authors assessed the likely potential of both technologies under various circumstances. The study covered the period 1980–2005, in five segments of five years. It focused only on the subsystem of the energy end‐uses which can be substituted for by solar thermal and biogas technologies.The overall non‐renewable sources which can be saved in 20 years by these technologies total 450 PJ (1 PJ = 101 5J) if the fuel prices rise at 0 per cent average annual, 1450 PJ if the fuel prices rise at 4.2 per cent average annual, 1860 PJ if the fuel prices rise at 7.2 per cent average annual and 3780 PJ if the fuel prices rise at 15 per cent average annual.However the most competitive technologies appear to be solar water heaters used mainly in the private and commercial sectors and biogas systems used mainly in the agricultural sector.The study was carried out by APRE under ENEA (formerly CNEN) contract and was intended to serve as an analytical basis for establishing an overall development and demonstration strategy for end‐use renewable technologies i

ISSN:0363-907X    

DOI:10.1002/er.4440090105

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe effect of solar radiation availability on the performance of different solar heating systems has been studied. The systems include a solar water heater, passive solar houses and district solar heating systems with seasonal heat storage. Also, different collector orientations and collector types have been investigated. The hourly radiation data were generated by a simple computational simulation procedure. It was found that district solar heating systems with concentrating collectors and passive solar houses showed the largest variations for the given conditions.

ISSN:0363-907X    

DOI:10.1002/er.4440090106

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe analyse the time and volume distributions for hot water consumption using data acquired from seven New Zealand households. This shows that there is a high proportion of low volume draws, 50 per cent yielding less than 2–31, depending on the household. In addition draws tend to be separated by relatively short intervals, 50 per cent following the previous draw by not more than 10–20 min. By use of a dynamic model of the hot water piping we estimate that thermal losses in the piping exceed 20 per cent of the heat energy supplied by the hot water cylinder for average households. We show that the use of pipe insulation may reduce these losses by 5–7 per

ISSN:0363-907X    

DOI:10.1002/er.4440090107

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe present results from a field study of a heat pump domestic hot water heater. The data demonstrate that the system was able to maintain a high standard of hot water service to all participants and in some cases actually improved the standard. The heat pump was able to realize annual average savings of 50–58 per cent when compared to conventional resistive water heaters. We also show that, in New Zealand, large scale application of this type of heat pump should become an economic alternative to the construction of new electrical generating capacity in the 1990

ISSN:0363-907X    

DOI:10.1002/er.4440090108

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe performance of the European Community Second Energy Research and Development Programme is reviewed and some of the important developments are highlighted. The contributions that have been made in the various areas of interest, energy conservation, solar energy, hydrogen, geothermal energy and energy systems analysis, are discussed and examples are given of the advances that have been made.

ISSN:0363-907X    

DOI:10.1002/er.4440090109

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe paper reports performance and testing of an improved solar water heater cum steam cooker. The efficiency of the system as a solar water heater is 51.5 per cent and as a solar steam cooker is 16.1 per cent.

ISSN:0363-907X    

DOI:10.1002/er.4440090110

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

年代:1985

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440090111

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

年代:1985

数据来源: WILEY