摘要:

AbstractThis investigation is devoted a study of the heat transfer process below and adjacent to cold stores. Numerically, the cold store dimensions, temperatures, floor level, insulation thickness, and the initial soil temperatures were considered. Experimentally, a series of runs were assessed to verify the numerical model, and the outcome was acceptable. Finally, the study revealed an expression for both average floor heat flux, and the time required for the soil to achieve 0°C

ISSN:0363-907X    

DOI:10.1002/er.4440140602

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

年代:1990

数据来源: WILEY

摘要:

AbstractA numerical solution of the differential equations governing the stability of the wide‐gap flow between two concentric cylinders is presented, taking into account the presence of a radial temperature gradient between the two cylinders when they are maintained at different temperatures. The critical Taylor numberTcand the critical wavenumberacare shown graphically for different values of η (the ratio of the radii of two cylinders), μ≤O (the ratio of the angular velocities of the two cylinders) and the positive and negative temperature gradient given by a parameter ±N( =Ra/T, where Ra =Rayleigh number). The results are discussed in terms of the parameters η,

ISSN:0363-907X    

DOI:10.1002/er.4440140603

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

年代:1990

数据来源: WILEY

摘要:

AbstractCumulative exergy losses result from the irreversibility of the links of a technological network leading from raw materials and fuels extracted from nature to the product under consideration. The sum of these losses can be apportioned into partial exergy losses (associated with particular links of the technological network) or into constituent exergy losses (associated with constituent subprocesses of the network). The methods of calculation of the partial and constituent exergy losses are presented, taking into account the useful byproducts substituting the major products of other processes. Analyses of partial and constituent exergy losses are made for the technological network of lead metal production.

ISSN:0363-907X    

DOI:10.1002/er.4440140604

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

年代:1990

数据来源: WILEY

摘要:

AbstractAcetamide, as a phase‐change material for energy storage, is preferable to other organic materials because of its noncorrosive behaviour and the high storage capacity (264 MJ/m3). In the paper a possibility is offered for a considerable decrease of the supercooling tendency and for the prevention of the disturbing sublimation effects, by modifying the dynamic working function principle ‘Galisol’. For this purpose we have used a heat‐transfer liquid with a partial solubility for acetamide. The study reviews solubility data, investigations of the thermal behaviour by the DTA method with large samples, cloud point investigations, equilibrium surface tensions and heat‐storage investigations of combinations of acetamide and heat‐transfer liquids. A phase diagram of the acetamide‐trichloroethylene system is presented. The heat‐storage behaviour of acetamide in its combination with trichloroethylene and a surface active material is very promising and offers a high heat‐transfer power comparable to that of inorganic salt hydrates under ‘Galisol’ conditions. Nevertheless, the fact that water‐free acetamide, which is very expensive, has to be used must be t

ISSN:0363-907X    

DOI:10.1002/er.4440140605

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper describes the various methods that lead to the development of high efficiency woodstoves. The main design constraints that need to be adhered to are the reduction in fuel consumption, keeping the power output higher than, or the same as, that of the traditional system, and the incorporation of user friendly aspects such as low weight, low floor area, low cost, etc. The parameters that affect the stove performance most are the combustion chamber parameters, the fuel parameters and the self‐draught parameters. The effects of these are discussed in detail. Some design considerations, such as matching of the heat transfer coefficients, matching of the heat source and the heat exchanger, maximization of the area of contact between the vessel and the flame, and the choice of chamber diameter are also described. Discouraging the use of clay vessels and encouraging the use of grates in traditional stoves can alone decrease the fuel consumption to about half of the present consumption besides increasing the power output. The results of this study will provide working information for stove designers towards the development of high efficiency woodstove

ISSN:0363-907X    

DOI:10.1002/er.4440140606

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper presents a fast converging method for the optimal allocation of capacitors/inductors in a power system, which will minimize its energy losses and improve its voltage profile. The problem is decomposed into investment and operation subproblems and is solved by linear programming based on the Benders decomposition method. The revised simplex method is proposed for the solution of the investment subproblem, and the Dantzig‐Wolfe decomposition method is used to solve the operation subproblem. This procedure has been generalized to represent multiple load levels and contingencies. Potentials of the proposed model and its solution methods have been demonstrated by its application to a typical power syste

ISSN:0363-907X    

DOI:10.1002/er.4440140607

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe geometrical profile of a seasonally adjusted solar concentrator composed of plane mirror elements and employing a tubular absorber has been optimized. The procedure maximizes concentration for any specified number of mirror elements, and for acceptance angle, with the height of the concentrator or the reflector area as a constraint. The geometrical characteristics of the optimal concentrators have been analysed in detail. The results for a tubular absorber are compared with those for a flat horizontal absorber. Detailed results for a wide range of number of mirror elements, reflector heights, and reflector areas are provided as a design aid. Designs using a glazed tubular absorber are also considered.

ISSN:0363-907X    

DOI:10.1002/er.4440140608

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper describes a computer based technoeconomic model that can accurately predict the impact of coal quality and other key variables on the busbar cost of electricity generated by new power plants. The model, IMPACT, focuses on the four major cost sectors of the coal‐to‐electricity chain: transportation, power plant, post combustion particulate and SO2emission controls, and waste disposal. Technically and economically established technologies in each sector are included in the model to facilitate a comprehensive evaluation of possible strategies. The user can select any combination of these technologies and evaluate the consequent impact on the busbar cost of electricity. Different strategies can be examined by selecting different options or through sensitivity analyses by changing coal or system parameters. IMPACT is structured to reflect regional and national cost differences by the use of appropriate cost indexes and site‐specific cost parameters; it is, therefore, independent of location.IMPACT is a flexible and powerful decision making tool that can be used for a variety of purposes such as exploring the various avenues open to a utility in the selection of a coal supply, or evaluating various emission control and waste disposal strategies, energy supply alternatives and utility expansion options. The model can also be used to determine the realistic value of a coal and optimal beneficiation levels; it can therefore be used by coal producers in the preparation of competitive

ISSN:0363-907X    

DOI:10.1002/er.4440140609

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

年代:1990

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440140610

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

年代:1990

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440140611

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

年代:1990

数据来源: WILEY