Keywords: energy analysis, entropy, exergy analysis, exergy efficiency, irreversibility, solar installation, air solar collectors, thermodynamics, fluid flow rate, air flow rate, Romania, solar energy, solar power, heating, exergy efficiency
Thermodynamic analysis of an air solar collector
The paper presents the experimental study of an air solar installation with a collecting area AC = 4.2m² and variable working fluid flow rate in the range 0.02÷0.06 kg/s. The experimental data are processed statistically through thermodynamic analysis, using energy (semi-empirical) and exergy methods. The aim of the paper is to establish the optimal air flow rate through this solar thermal system in order to ensure minimum irreversibility of the collecting-heating-cooling process under Romania's insolation conditions. The paper is also a demonstrative example of cost-effective and efficient use of solar energy for heating in Romania. It is experimentally proven that for this solar installation, the optimum air flow rate is of 0.04 kg/s. At a flow rate of 0.04 kg/s, irreversibility has the lowest values for all daytime hours with a maximum at noon (2640 W). For this flow rate the exergy efficiency reaches the highest value, ηex:max = 0:197.