摘要:

AbstractA mathematical model is presented for studying the techno‐economic performance of a hybrid solar air heating system. The configuration of the system consists of a collector‐cum‐storage system for solar heating of air, an adjuster unit for bringing down the higher air temperature to the desired limit by mixing fresh air in it, and an auxiliary energy source to provide the deficient amount of heat to the air to attain the desired temperature whenever required. In order to evaluate the performance of the system, numerical calculations have been made corresponding to the climatic data of Delhi and the cost parameters prevalent in the Indian market. Numerical results show that the cost of the useful energy obtained for optimized values of collector area and water‐depth is much less than the cost of electrical

ISSN:0363-907X    

DOI:10.1002/er.4440140702

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

年代:1990

数据来源: WILEY

摘要:

AbstractAn experimental study of an alkaline fuel cell test plant with a 0.5 kW fuel cell module is presented in this paper. The characteristics of the fuel cell module are measured in different steady state load conditions and with different electrolyte temperatures. The results are analysed by calculating the different efficiencies of the module.

ISSN:0363-907X    

DOI:10.1002/er.4440140703

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

年代:1990

数据来源: WILEY

摘要:

AbstractDimensional analysis was used to derive the physical properties for a small‐scale model building and its heating, ventilating, and air conditioning (HVAC) system. The model was built, and its thermal response was studied over a number of heating and cooling cycles. Temperature variation was recorded in the form of temperature/time plots. Experimental results showed the model to be capable of realistic behaviour. Detailed comparisons with full‐scale response could not be made, since an imaginary prototype was assumed. Recent computer simulation, however, produced results analogous to those obtained from the model tests. This suggests that small‐scale models can be used to quantitatively reproduce building energy response. Current efforts are being directed towards the modelling of an existing building, in which both air temperature and velocity will be measured. The aim is to validate small‐scale modelling as a viable tool in building‐energy

ISSN:0363-907X    

DOI:10.1002/er.4440140704

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper presents the results of some investigations to establish the validity of various correlations for estimating masstransfer rates in a solar still. For this purpose, the results of steady‐state experiments in a controlled environment are compared with the predictions of different correlations. It has been observed that the correlation leading to the widely used Dunkle's relation is valid only when the Grashof number is less than 2.51 × 105and needs modification for higher values of the Grashof numb

ISSN:0363-907X    

DOI:10.1002/er.4440140705

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe thermal performance of a room fitted with an evaporative cooler (desert cooler) has been analysed in terms of a ‘discomfort index’ for three different climates, namely hot dry, hot humid and composite typified by the Jodhpur, Madras and Delhi climates. The effects of different cooler parameters on the discomfort index of the room have been investigated to obtain the optimum values for each clim

ISSN:0363-907X    

DOI:10.1002/er.4440140706

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe addition of a heat pump to a conventional hot air drying system can enhance the efficiency of drying. To investigate the performance of heat pump assisted continuous drying system a detailed simulation model has been developed. The system modelled consists of a vapour compression heat pump coupled to a continuous cross‐flow dryer. The model takes account of detailed heat and mass transfer phenomena taking place in each component of the system and can be used to investigate many different system configuration

ISSN:0363-907X    

DOI:10.1002/er.4440140707

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe simulation model described in Part 1 (Jollyet al, 1990) is used to investigate the performance of heat pump assisted continuous drying. Several key system aspects, such as the evaporator air by‐pass ratio and the use of recuperators, are investigated. The criteria for evaluating system performance and comparing system options are the Specific Moisture Extraction Rate (SMER), the Coefficient of Performance (COP) and the product throughput. The simulations show that there has been some misunderstandings reported in the previous literature. In particular, the results show that the evaporator air by‐pass ratio is not as critical as previously indica

ISSN:0363-907X    

DOI:10.1002/er.4440140708

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

年代:1990

数据来源: WILEY

摘要:

AbstractHigh density polyethylene (HDPE), crosslinked by electron beams in air, is presented as a latent heat storage material for energy storage applications at a temperature level of about 120°C. The study includes thermal investigations before and after the irradiation, investigations of the form stability, gel content determinations and microscopic investigations of HDPE. An electron energy of 0.4 MeV and a radiation dosage of 200 kGy were found to be the optimum conditions for the irradiation of the investigated HDPE in air. The pellets obtained were form‐stable owing to the formation of a thin crosslinked surface layer (about 0.5 mm thickness). In spite of the presence of oxygen during irradiation, the melting enthalpy of the initial state was retained almost quantitatively. Apart from that, a quasicomplete irradiation of the pellets in volume in air, with a higher electron energy, is also possible. In this case about 95% of the initial melting enthalpy is obtained, providing a maximum gel content of 50%.Moreover, the paper offers a possibility of overcoming the low heat transfer power of HDPE by applying it in form of modified pellets in a ‘Galisol’ model storage unit with water as the heat transfer liquid. Owing to the large heat transfer area connected to boiling and condensation of water, excellent values of heat transfer power of 100–114 W/kg HDPE (ΔT=16 K) are obtained. These are comparable to those of salt hydrates, provided there is sufficient form stability. The significant influence of somewhat lower form stability on the heat output

ISSN:0363-907X    

DOI:10.1002/er.4440140709

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe heat transfer performance of Rijke combustors is experimentally studied for grade A and Grade B coals. It is found that the improvement in the heat transfer is more for grade A coal than for grade B coal. Furthermore, the location of the heat release region is found to be critical in obtaining the heat transfer improvement. It is also found that the mere presence of oscillatory combustion does not necessarily lead to improved heat transfer.

ISSN:0363-907X    

DOI:10.1002/er.4440140710

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.4440140711

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

年代:1990

数据来源: WILEY