Thermal management of high concentrator photovoltaic system using a novel double-layer tree-shaped fractal microchannel heat sink

Abstract

With the aim to overcome the excessive temperature and uneven temperature distribution on cells in high concentrator photovoltaic (HCPV) system, a novel cooling method based on double-layer tree-shaped fractal microchannel heat sink (FMCHS) is proposed. A three-dimensional heat transfer and flow model is established. The effects of four different flow modes and inlet velocity on thermal-hydraulic performance, cell surface temperature and electrical efficiency are investigated. The results show that compared with single-layer FMCHS, under unilateral, bilateral, inner and cross flow modes, the average temperature of cell surface (Tcell) are decreased by 2.14%, 1.65%, 1.61% and 1.41%, respectively; while the temperature difference of cell surface (ΔT) are decreased by 84.9%, 82.6%, 70.9% and 72.8%, respectively. For double-layer FMCHS, ΔT under four flow modes are all less than 3 K; the inner flow has the best cooling effect, which can minimize Tcell and ΔT to 339.2 and 2.1 K respectively, and maximize electrical efficiency (ηcell) to 41.68%. With increasing inlet velocity from 0.5 to 2 m s−1, for double-layer FMCHS under inner flow, Tcell is decreased by 11.7 K. The designed double-layer FMCHS has higher cooling performance than single-layer FMCHS, and can ensure the efficient and safe operation of HCPV system.