Direct liquid-immersion cooling of solar cells was adopted in a narrow rectangular channel receiver for linear concentrating photovoltaic (CPV) systems. Dimethyl silicon oil with viscosity of 2 mm(2)/s was used as working liquid. In order to obtain an optimized receiver channel height by computational fluid dynamics (CFD) simulation, effect of liquid thickness on silicon solar cell efficiency was investigated experimentally firstly, and then CFD models, which were validated by experimental data, were established. Performance of the optimized receiver was predicted. Force analysis of the receiver and heat transfer performance prediction of different immersion liquids were conducted. Experimental results show that silicon solar cell efficiency decreases with increasing thickness of immersion liquid, and silicon oil thickness on top of the cell should be lower than 12.0 mm in order to achieve a cell efficiency promotion by liquid immersion. Simulation results show that smaller channel makes for better heat transfer performance but larger flow resistance, and 10 mm is recommended as the optimal channel height. According to the force analysis result, the recommended cover glass thickness should not be less than 3.0 mm and the width should be within 85 mm. A general regression equation of Nu = 0.067Re(0.714)Pr(0.35) is obtained. (C) 2015 Elsevier Ltd. All rights reserved.