This paper presents a solar photovoltaic/thermal (PV/T) system with triple-junction solar cells. The essential components of the system are a concentrator of high concentration ratio, a PV/T module and a tracking device. Plane-mirrors array structure is applied to the concentrator, which can provide PV/T module with a uniform light intensity distribution and an adjustable concentration ratio. The PV/T module is an integration of triple-junction solar cells and a heat exchange device, where the heat from triple-junction solar cells is collected and transported for thermal applications by fluid passing through. Considering both photovoltaic and thermal conversion, the total solar utilization efficiency is greatly increased. The simulation results show that the thermal conversion efficiency of this high concentration PV/T system in hybrid operation can achieve about 52%, which is approximately in agreement with the experimental result of 48%, meanwhile the theoretical photovoltaic conversion efficiency can reach 26%. The simulation results also reveal the effect of fluid flow rate on the thermal efficiency of high concentration PV/T system, which is quite opposite to that in non-concentration PV/T system. (C) 2014 Elsevier Ltd. All rights reserved.