摘要:

This paper presents experimental performance of an ejector refrigeration system using methanol as the working fluid. The work is part of a research project to investigate and develop passive ejector refrigeration using natural “environmentally friendly” fluids. The passivity could be achieved by utilizing either the capillary head of heat pipe devices or the gravity head of a vertical column of liquid to circulate the working fluid between the condenser and the steam generator. The system would be suitable for cooling buildings or use as a vehicle air conditioning system and would provide substantial economic and environmental benefits. The passivity of the system would give it a potential of long life and unlike vapour-compression units, it would produce no noise or vibration and require less frequent servicing. Results of the experiments are presented and compared with those for a water-based ejector refrigeration system. A coefficient of performance (COP) between 0.2 and 0.4 would be possible using low grade heat, such as solar energy and waste heat. Results also showed the possibility of achieving evaporator temperatures below the freezing point of water, which of course would not be possible with a water ejector refrigeration system.

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675348

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A dynamic computer simulation model has been developed to evaluate the energy performance of buildings cladded with Transparent Honeycomb Insulation (THI). The U-value of THI is dependent upon the honeycomb cell dimensions, thermal characteristics of the material and temperatures encountered across the honeycomb insulation. Solar transmittance of THI is also angle-dependent. Two new modules for TRNSYS have been developed to incorporate these two special characteristics of honeycomb insulation in the simulation model. The simulation model not only confirms convection suppression capability of the insulation but also facilitates the change in the design and material of THI during simulation. As an example a room with a transparently insulated thermal storage wall has been simulated and results show minimising the heat loss and maximising the solar gain potential of THI.

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675349

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The simplified methods for the heating requirement calculation used in the new standard proposals are based on the utilisation factor for counting the dynamic effect of the building envelope. The proposed correlations give results only partially in agreement with detailed dynamic simulations.

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675350

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Results of a questionnaire-based preliminary survey of biomass briquetting plants in India are briefly presented. Typical schedules for the repair and replacement of various components as arrived at in the study are also presented along with a summary of suggestions made by briquetting plant owners.

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675351

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This communication presents the Second Law analysis based on the exergy concept for the performance of Simple and Regenerative-Reheat Rankine heat engines generally used in Solar Thermal Power Systems. Basic energy and exergy analysis for the heat engine system components are carried out for evaluating the energy and exergy losses as well as the exergetic efficiencies for both the Simple and Regenerative-Reheat Rankine heat engines. Relevant energy and exergy flow diagrams are drawn to show the various thermodynamic and thermal losses. It is found from the results that most of the exergy losses occur in the boiler and these losses are significantly reduced by the incorporation of a regenerator and reheater, whereas the results of the energy analysis shows that the main energy loss takes place in the condenser. This is because in the boiler high quality energy is lost but in the condenser low quality energy is lost. The incorporation of the regenerator and reheater results in a reduction of the total irreversibility rate of the cycle by 28.77%. The corresponding improvement in the exergetic efficiency is 16.42%.

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675352

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675353

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675354

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.2000.9675347

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor