Performance evaluation of high concentration photovoltaic cells cooled by microchannels heat sink with serpentine reentrant microchannels

Efficient cooling is critical to reduce cell temperatures of high concentration photovoltaic (HCPV) cells to avoid the output electrical performance degradation and lifetime reduction. In this study, we develop a novel type of microchannel heat sink (MHS) with serpentine reentrant microchannels (SRM) for efficient cooling of HCPV cells. They feature serpentine flow passages with omega-shaped cross-sectional configurations, which contribute to promote fluid mixing and disrupt the normal development of thermal boundary layers. Thus they are able to provide excellent heat transfer characteristics and highly efficient cooling performance. By the comparison of a fin heat sink, both numerical and outdoor experimental studies were comprehensively conducted to explore the enhancement feasibility of thermal and electrical performance of HCPV cells. Results showed that the SRM reduced the cell temperatures and enhanced the temperature uniformity of HCPV cell module considerably, i.e., it presented cell temperatures of 25-31 degrees C, much smaller than that of 45-63 degrees C of the fin heat sink. The temper-ature differences of HCPV cell modules were reduced to be less than 4.4 degrees C. Besides, the output power increased by as high as 115%, and the electrical efficiency increased to 15-20% for the HCPV cell module with serpentine reentrant microchannels. Besides, the HCPV cell module with SRM was also found to induce smaller average cell temperatures and better electrical performance than a module with parallel reentrant microchannels (PRM). Moreover, the effects of flow rate and concentration ratio on the performance of HCPV cells with SRM were also assessed.