Comparative Optical and Thermal Analysis of Compound Parabolic Solar Collector with Fixed and Variable Concentration Ratio

Solar thermal collectors, such as flat plate and evacuated tube collectors, are used for maximum of 60–80 °C temperature and parabolic trough collectors are used for 700–900 °C temperature ranges. It is needed to develop and analyze solar collectors, such as compound parabolic collectors (CPC) which can operate in an intermediate temperature range from 50–300 °C for industrial and domestic applications. However, optical and thermal performance of CPC is strongly influenced by concentration ratio. The current study presents a comparative optical and thermal analysis of CPC with fixed (4) and variable (4.5 to 5.7) concentration ratio by using model-based transient simulation approach. Two profiles of compound parabolic collector are analyzed with fixed and variable concentration ratio for the subtropical climate of Taxila, Pakistan. 2D profiles of both collectors are modeled and designed in MATLAB and are then analyzed optically by using Monte Carlo ray tracing technique through TracePro. In addition, thermal analysis of both profiles is also performed through ANSYS. The resulting optical efficiencies with fixed and variable concentration are 72% and 79%, respectively. Whereas maximum temperature achieved with both profiles is 352 K and 367 K, respectively. Thus, it is concluded that performance of CPC with variable concentration ratio is much better compared to fixed value.