No abstract

Due to the low thermal performance of solar air heater, different methodologies are adopted to increase its performance namely fins, artificial roughness etc. Thermal performance is obtained for different values of Reynolds number, emissivity of a plate, tilt angle and by employing different kinds of artificial roughness.  There are numerous techniques which can be used on the absorber plate to increase the efficiency and Thermo-hydraulic performance of the solar air heater. We can use single roughness geometry or can combine two different roughness geometries also to get best output. By defining different correlations of heat transfer and friction factor in roughened ducts of solar air heater, we can get the best artificial roughness that can be utilized in the solar air heater. By selecting the coating material, we can improve the performance of solar air heater. As we must use our energy for future purpose, we have to store it and for that thermal energy storage materials are used. This is also one of the techniques to increase the effectiveness of solar air heater. In this article, focus has been given on study of methods of increasing the performance of solar air heater such as providing artificial roughness, increasing the collector aspect ratio etc.

This study conducts an experimental analysis of a vapor compression refrigeration system (VCRS) test rig on the basis of first and second laws of thermodynamics. Performance analysis of the VCRS was conducted in winter and summer climatic conditions. The results show that high coefficient of performance (COP) is achieved in winter under both first and second law of thermodynamics analysis.

Energy-Energy analysis of present vapour compression refrigeration system is done using isentropic fluid as refrigerants R134a.This thermodynamic analysis is carried out by 2nd law of thermodynamic approach in terms of COPII. The performance of the system both theoretical and actual experimental have been computed in summer condition. The results of proposed title explain the high-grade energy consumption by compressor with 1 TR of cooling effect. COPII indicates the actual energy output from the system in summer climate. Due to higher GWP and ODP of R22, R134a can be used for domestic / commercial and industrial applications.