A liquid-immersion cooling method is proposed for efficient heat removal from densely packed solar cells in highly concentrating systems. The direct-contact heat transfer performance was investigated under different concentration ratios, liquid temperatures and flow velocities, Electrical performance of the immersed module was also measured. Experimental results show that the module temperature can be cooled to lower than 45 degrees C and the convective heat transfer coefficient can be higher than 3000W/m(2) degrees C. The module temperature decreases with higher flow velocity and lower medium temperature. The open circuit voltage of the immersed module drops about 0.3% per degrees C increase and the short circuit current increases with the light density. The Simulation results are in fairly good agreement with the experimental data. From the simulation it is found that a temperature difference of only 0.09 degrees C exists between the soldered base and the cell and that the main heat transfer resistance is a result of the laminar flow layer over the cell's Surface. (C) 2009 Elsevier B.V. All rights reserved.