STUDY ON THE THERMAL PERFORMANCE OF EVACUATED SOLAR COLLECTOR SYSTEM

Abstract

The experimental work was carried out in Faculty of Agriculture, Tanta University, Egypt, which located at latitude and longitude angle of 30.49°N and 30.59°E, respectively, during winter and summer seasons 2015. The experiments were designed to evaluate the thermal performance of evacuated tube solar water collector ETC with 20 evacuated tubes, tank capacity 150 liters and net surface area of 1.5 m2. The thermal efficiency for evacuated tube solar collector depends on the solar radiation, ambient temperature from sunrise to sunset. The obtained results showed that the maximum outlet water temperatures were 63 and 85.7°C during winter and summer seasons, respectively. Also, the differences between outlet water temperatures and ambient air temperatures were 46.2 and 50.1°C, and the temperature differences between outlet water temperature and inlet water temperature from sunrise to sunset were 17.09 and 17.30°C during two different seasons. While, the overall efficiency values were 77.20 and 79.90%. In addition, the linear regression analysis showed that the absorbed solar energy (Qa) was a function in available solar radiation (Q). Therefore, can be estimated the values of absorbed solar energy from the following equation: Qa = 0.818 Q ,( R2 = 0.999).