摘要:

AbstractA thermodynamic analysis of the vapour absorption heat pump (VAHP) cycle is made to study the performance of four fluorocarbon based working fluid pairs namely, R21‐DMETEG, R21‐DMF, R22‐DMETEG and R22‐DMF. The performance characteristics compared are total heat output per unit solution flow rate; heating coefficient of performance; second law efficiency and circulation ratio. Among the four combinations, R21‐DMETEG stands out as the most suitable solution for low temperature VAHP applications. Correlations are given for quick estimation of COP and limiting generator temperature. The effects of mass transfer effectiveness at generator and absorber on the performance are also inv

ISSN:0363-907X    

DOI:10.1002/er.4440130102

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe growing depositories of fine and discard coal, produced as a result of increasing beneficiation practice, as well as the problems associated with the disposal of timber and agricultural residues, have prompted an investigation of their use as briquetted and pelletized fuels for domestic application. More specifically, the viability of introducing such reconstituted fuels into areas of South Africa which have no access to electricity, and rely principally on fuelwood for energy supply, is assessed. The contribution which high calorific value reconstituted fuels could make to national energy supply is estimated at 224 peta joules (PJ) per annum, or roughly 10 per cent of total demand. This is in excess of 80 per cent of current consumption within underdeveloped areas and is equal to total fuelwood consumption. The cost of producing reconstituted fuels, at centralized facilities, is estimated for a number of processes, including coal briquetting with, and without, the addition of binding agents, extrusion of a coal/paper composite, and extrusion of wood waste. Their overall economic viability is assessed for eleven communities which are thought to cover the range of settlement patterns within the underdeveloed sector. If waste coal is made available at a price proportional to the cost of disposal and reclamation, rather than one linked to its inherent energy value, then, in most cases, the minimum ‘as delivered’ price of the waste derived fuel product is less than current energy expenditure. It is felt that the introduction of reconstituted fuels into the underdeveloped sector would be favourably met, particularly where it is seen to offer a clean burning alternative to current practice. Areas which produce high quality discard coal are identified, and its use discussed as part of a strategy for implementing a ‘waste‐to‐energy’ scheme. It is stressed that energy shortages in underdeveloped areas are largely the result of the existing socio‐political order, and that a national energy programme should consider the introduction of reconstituted fuels as only one, short‐term, way to ameliorate

ISSN:0363-907X    

DOI:10.1002/er.4440130103

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe evidence of the cycle stability of a latent heat storage unit is an important requirement of its technical application. In this paper an apparatus for investigation of Galisol (GLS) latent heat storage substance combinations is described. The stored heat and the heat transfer power are determined with an uncertainty of ± 5 per cent by means of the applied calibration. The results of the cycle stability of the Glauber salt in its substance combination confirm the stability behaviour of this salt hydrate under the dynamic conditions of the GLS storage unit

ISSN:0363-907X    

DOI:10.1002/er.4440130104

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

年代:1989

数据来源: WILEY

摘要:

AbstractVarious correlations available in literature for predicting two‐phase heat transfer coefficient in annular flow regime are reviewed. Accurate prediction of these coefficients effect not merely the efficient and economic design of equipment but also its safety in operation. Instabilities can result in boiling crises, disturb the control systems and cause mechanical damage. It is observed that applicability of these correlations for a multi‐tubular heat exchanger has not been investigated. Experimental studies on a heat pump assisted distillation unit have been conducted. Results show that the actual values of heat transfer coefficients are consistently higher than those predicted by Shah, Pierre and Guerrier's correlati

ISSN:0363-907X    

DOI:10.1002/er.4440130105

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

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper discusses the problems of using refuse‐recovered low Btu gases as fuel of high‐temperature regenerative gas turbines. First, it is briefly described that the system using refuse‐recovered fuels has a great possibility of being superior both in energy conservation and in solving refuse disposal problems in urban areas. Next, by taking a fermentation gas of the sewage sludge and a pyrolysis gas of the municipal refuse as examples, it is confirmed that a combustion gas with the high flame temperature required for a high efficiency gas turbine can sufficiently be obtained. Finally, through a case study in which no special condition is assumed, the system using these refuse‐recovered low Btu gases whose flame temperatures are low is shown to be excellent in the thermal NOxformation characteristics as compared to that using the conventional fuel with a high calorifi

ISSN:0363-907X    

DOI:10.1002/er.4440130106

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe cyclic decomposition of cupric oxide followed by the oxidation of cuprous oxide in air was studied, in order to investigate the potential use of this reaction cycle for chemical energy storage. Isothermal and non‐isothermal thermogravimetric method was used to study the kinetics of these reactions. The activation energy of the forward reaction (decomposition) is 313.0 kJ mol−1in the temperature range 760–910°C, while that for the backward reaction is 76.5 kJ mol−1in the temperature range 400–500°C. The reaction reactivity was found to be essentially unchanged for up to 20 cycles. This was explained as due to the swelling of the CuO particles and the development of a highly porous structure on repea

ISSN:0363-907X    

DOI:10.1002/er.4440130107

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

年代:1989

数据来源: WILEY

摘要:

AbstractA dynamic method is used to predict the liquid axial dispersion coefficient in cooling towers. A KCl tracer was employed on the water inlet on the top of the tower. Input and response signals were measured. Cooling tower parameters were determined by predicting the response tracer signal and curve fitting technique in the time domain.

ISSN:0363-907X    

DOI:10.1002/er.4440130108

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

年代:1989

数据来源: WILEY

摘要:

AbstractElementary and improved sorption‐compression heat pumps are defined and recent developments are reviewed. The merits of the most interesting type, i.e. the resorption‐compression (RC‐) heat pump, are discussed. The performance of an industrial pilot RC‐heat pump for production of process vapour is described. Some performance and cost examples for different applications ar

ISSN:0363-907X    

DOI:10.1002/er.4440130109

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

年代:1989

数据来源: WILEY

摘要:

AbstractWood is a major cooking fuel in rural areas of many developing countries and is burnt in vessel mounted stoves. Multipot chimney type cookstoves were introduced about forty years ago to overcome problems of smoke and to increase the conversion efficiency. Although widely propagated, there is still scope to improve the design of these stoves based on a critical evaluation of performance and an understanding of the basic principles of heat transfer, fluid mechanics and heat release. This paper describes in detail the results of thermal performance studies conducted on three widely propagated stove versions with respect to all operating variables. Based on the analysis, certain broad guidelines were arrived at for design of a proper stove. Another widely propagated version was taken up for detailed optimisation study in the light of such guidelines resulting in the development of a high efficiency design. The performance of the optimized unit is compared with the original version.This study leads to the conclusion that except for pot placement schemes and geometric shapes, the wide variety of stoves (over 60) being propagated under various trade names are not really different and the optimum parameters depend only on the fuel burning rate desired.

ISSN:0363-907X    

DOI:10.1002/er.4440130110

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe paper deals with an analysis in terms of production function of a simplified Beau de Rochas irreversible engine. The combustion reaction is the main source of irreversibility. The production function is concave. This property is an extension of similar behaviours for endoreversible heat engines.

ISSN:0363-907X    

DOI:10.1002/er.4440130111

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

年代:1989

数据来源: WILEY