Thermal and thermohydraulic performance evaluation of an evacuated tube collector solar air heater
Loading...
Date
2018
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Punjab Agricultural University, Ludhiana
Abstract
The thermal and thermohydraulic performance of an evacuated tube collector (ETC) solar air heater and flat plate collector solar air heater (FPC) were experimentally investigated and compared in the outdoor conditions at different mass flow rates of air. ETC collector having two square channels and 15 one ended tubes were used in the present study. The aperture area of ETC and FPC was 0.83 m2 and 1.33 m2 respectively. The mass flow rate was varied from 0.002 kg/s-m2 to 0.012 kg/s-m2 in six levels for both the collectors. A mathematical method was used to evaluate the daily collectible solar radiation on single tube of all glass ETC collectors. The maximum values of outlet air temperature and rise in temperature of ETC and FPC were observed to be 110.8 °C,71.8 °C, 68.8 °C and 30.3 °C respectively corresponding to mass flow rate of 0.002 kg/s-m2. The maximum thermal efficiency of ETC and FPC were found to be 86.47% and 39.33 % at mass flow rate of 0.012 Kg/s-m2. The maximum pressure drop across ETC and FPC collectors were observed to be 51.3 Pa and 2.7 Pa respectively, corresponding to mass flow rate 0.012 kg/s-m2. Whereas, the maximum thermohydraulic efficiency of ETC and FPC were obtained as 86.11 % and 39.31 % respectively corresponding to the mass flow rate of 0.012 Kg/s-m2. On the basis of thermal and thermohydraulic performance, ETC solar air heater has found to be better as compared to the FPC solar air heater.
Description
Keywords
null