摘要:

AbstractA theoretical and experimental study of transient heat transfer in the heating of an individual slab product, subjected to an air flow at a temperature of 50°C and a velocity of 1 m/s, is presented. Experimental temperature measurements at the centre of the slab product were made, and the experimental heat‐transfer rates were derived from the temperature data. A simplified analytical technique, using the boundary condition of the third kind in transient heat transfer, was used to predict the theoretical heat transfer rates for two cases, the first considering that the heat transfer coefficient is a convective heat transfer coefficient, and the second considering that heat transfer coefficient is the sum of the convective and radiative heat transfer coefficients. The experimental heat‐transfer rates were compared with the predictions for two cases, and a very good agreement was obta

ISSN:0363-907X    

DOI:10.1002/er.4440170502

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

年代:1993

数据来源: WILEY

摘要:

AbstractPreservation ofCalotropis procera(Ait.) R.Br. latex was studied in terms of changes in pH, colour and the extent of coagulation on using various preservatives. In addition, a comparison of synthetic and natural coagulating agents was made for coagulation ofC. proceralatex for biocrude production. Natural coagulant (bark extract) was found to be better than synthetic coagulants. A quick light‐scattering technique was developed to study the extent of coagulation and the yield of biocrud

ISSN:0363-907X    

DOI:10.1002/er.4440170503

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

年代:1993

数据来源: WILEY

摘要:

AbstractNitrilotriacetic acid (NTA) and Azur‐A were used as the reductant and photosensitizer, respectively, for the photo‐generation of electrical current. The photocurrent and photopotential generated by the cell were 60 μA and 362 mV, respectively. The effects of various parameters on the electrical output of the cell were also observed. The mechanism for the generation of photocurrent in this cell has been proposed. The maximum power obtained from this cell is 17.8

ISSN:0363-907X    

DOI:10.1002/er.4440170504

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

年代:1993

数据来源: WILEY

摘要:

AbstractIn this communication, an analytical expression for the thermal efficiency of an active regenerative solar distillation system has been presented in terms of the design parameters of the solar still, an effectiveness of the heat exchanger, a number of transfer unit (NTU) and the collectors. It is observed that there is a significant improvement (50%) in the overall thermal efficiency, owing to the regenerative effect, which is in an accordance with the experimental results.

ISSN:0363-907X    

DOI:10.1002/er.4440170505

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper deals with the transient analysis of rock bed air heaters in three different configurations. The analysis has been carried out for both summer and winter weather conditions to explore the feasibility of their use in summer for crop‐drying applications and in winter for space‐heating and water‐heating applications. A parallel study has also been performed on the conventional empty channel air heater to compare its performance with that of rock bed air he

ISSN:0363-907X    

DOI:10.1002/er.4440170506

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper will show some of the problems that may be encountered when using a compact plate exchanger as an evaporator in a refrigeration system which utilizes a thermostatic expansion valve as its controlling device.

ISSN:0363-907X    

DOI:10.1002/er.4440170507

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

年代:1993

数据来源: WILEY

摘要:

AbstractExisting calculation methods of the transient heat flow through walls for air‐conditioning applications, assume periodic outdoor conditions. Therefore, the effect of a temporary temperature rise on the indoor heat flow is usually neglected. In the present work an attempt is being made to model the related non‐periodic transient problem. The method of approach is based on a finite‐difference solution of the transient heat conduction equation within the wall. Outdoor air temperature deviation parameters are introduced, which characterize any temporary deviation of the outdoor air‐temperature from periodicity. Indoor heat flow deviation characteristics are defined, which describe the deviation of the indoor heat flow from periodicity, provoked by the corresponding outdoor air temperature deviation. A parametric study is conducted, where the effects of the temperature deviation parameters on the indoor heat flow deviation characteristics are examined. It has been found that (a) the maximum heat flow deviation varies linearly with the mean temperature difference, (b) the restoration ratio is practically independent of the temperature amplitude difference, and (c) an increase in the wall thermal diffusivity results in a decrease of the maximum heat flow deviation. The practical importance of the present analysis is that it helps towards the estimation of peak loads under non‐periodic outdoor c

ISSN:0363-907X    

DOI:10.1002/er.4440170508

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

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper examines the impact of the fluctuations in oil revenue on the import patterns of the GCC countries. The study is adisaggregatedanalysis of the relationship between imports of various commodity groups, using two‐digit SIT classifications and per capita income in each of the six members of the Gulf Cooperation Council (GCC). The research shows that the reduction in oil revenue since late 1982 has completely upset the import‐income relationship which was developed during the boom years, 1974

ISSN:0363-907X    

DOI:10.1002/er.4440170509

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

年代:1993

数据来源: WILEY

摘要:

AbstractScheduling methods, which reduce undesirable emissions from fossil‐fuel generating units, has been a matter of considerable interest to power utilities. This paper introduces the idea that overall emission‐reduction for a system can be achieved by optimizing the emissions at a few most emissive units, instead of doing so at all units. Such an approach becomes effective provided a sufficiently large cluster of the emissive units are subjected to the emission‐optimization process.One important aspect of the problem that is addressed in the paper concerns the development of a suitable objective function which takes into account the cost‐effectiveness of emission reduction. Both overall generation cost, as well as the emission at selected generating units, are taken relative to the respective base‐case (non‐optimal emission) values. The relative‐cost and relative‐emission terms are then included in a common ‘penalty function’, which is dimensionless. Minimization of this penalty function leads to an optimal operating point, at which a comparison of the reduction in overall relative‐emission to the increase in relative‐cost indicates the cost‐effectiveness of the corresponding generation schedule.The approach is tested for an existing three‐region scenario that forms part of the Indian power system. Results indicate the extent to which individual emissions can be reducedvis‐a‐visthe corresponding increas

ISSN:0363-907X    

DOI:10.1002/er.4440170510

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

年代:1993

数据来源: WILEY

摘要:

AbstractThe performance of a vapour‐compression system was examined with both R12/mineral oil and R134a/mineral oil charges. The mineral oil was then removed from the system using a multiple flushing method and the experiments repeated using a charge of R134a and an ester‐based lubricant to establish the effect of the oil on the performance of the system. Results were compared with theoretical data for R134a and R12 refrigera

ISSN:0363-907X    

DOI:10.1002/er.4440170511

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

年代:1993

数据来源: WILEY