Volume 16: Low Carbon Cities and Urban Energy Systems: Part V

Numerical Study on Effects of Sudden Heat Flux Increase on Flow Pattern in Straight Microchannel for CPV Cooling Li Tongling, Yu Hao, Li Wenfei, Zhuang Jiaojiao, Meng Shuangshuang, Mao Ning

Abstract

Microchannel boiling was used for cooling concentrated photovoltaic (CPV) due to its promising heat transfer performance, to maintain the normal operating of CPV at a high efficiency. However, fluctuating and non-uniform heat fluxes of CPVs may lead to deterioration of flow boiling and heat transfer of microchannel, and then reduce the heat dissipation performance of CPV, and lead to damage of solar cells. To improve this key point, a rectangular straight microchannel with deionized (DI) water boiling was numerically simulated using VOF method, four sudden heat flux increase levels were set: 97.96, 199.64, 284.54 and 580 kW/m2. The effects of sudden heat flux increase on the two-phase flow pattern was studied. It was found the higher heat flux increase advanced the generation of water vapor phase and transition. The water vapor volume fraction was instantaneously increased and easily moved to instability under heat flux increase of 580 kW/m2.

Keywords CPV cooling, Microchannel flow boiling, Flow pattern, Sudden heat flux increase, Numerical study