Exergy Analysis of Flat Plate Solar Collectors

Entropy

Zhong Ge¹  Huitao Wang¹  Hua Wang¹  Songyuan Zhang¹ 

[1] Engineering Research Center of Metallurgical Energy Conservation and Emission Reduction, Ministry of Education Kunming University of Science and Technology, Kunming 650093, China; E-Mails:

关键词: flat plate collector;    heat loss coefficient;    exergy;    exergy loss;   

DOI  :  10.3390/e16052549

来源: mdpi

【 摘 要 】

This study proposes the concept of the local heat loss coefficient and examines the calculation method for the average heat loss coefficient and the average absorber plate temperature. It also presents an exergy analysis model of flat plate collectors, considering non-uniformity in temperature distribution along the absorber plate. The computation results agree well with experimental data. The effects of ambient temperature, solar irradiance, fluid inlet temperature, and fluid mass flow rate on useful heat rate, useful exergy rate, and exergy loss rate are examined. An optimal fluid inlet temperature exists for obtaining the maximum useful exergy rate. The calculated optimal fluid inlet temperature is 69 °C, and the maximum useful exergy rate is 101.6 W. Exergy rate distribution is analyzed when ambient temperature, solar irradiance, fluid mass flow rate, and fluid inlet temperature are set to 20 °C, 800 W/m², 0.05 kg/s, and 50 °C, respectively. The exergy efficiency is 5.96%, and the largest exergy loss is caused by the temperature difference between the absorber plate surface and the sun, accounting for 72.86% of the total exergy rate.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland