Simulation Analysis of Overall Heat Loss Coefficient of Parabolic trough Solar Collector at Computed Optimal Air Gap

Parabolic trough collectors (PTC) are the highly popular systems employed for electricity generation, industrial process heating, steam generation, refrigeration and air conditioning, hot water production and its thermal efficiency directly depends on the overall heat loss coefficient (OHLC) of receiver and its operating temperature. Thus, the present study evaluates OHLC of receiver and heat loss components at optimum air gap and various parameters by iterative method. Results show that OHLC of receivers increases with increase in ambient temperature, wind velocity, receiver emissivity and temperature and decreases with increase in diameter. Lowest and highest loss factor are found as 5.55 Wm-2K-1 and 10.97 Wm-2K-1 for 7.62 cm and 1.2 cm receiver diameter respectively and convection/conductive losses are higher than radiation across the receiver.