An investigation of the heat transfer dependence for 3 DSSC (Dye Sensitized Solar Cells) modules in presence of Cocinia Indica, Eclipta Alba and Solanum Melongena Dye and 3 commercial microcrystalline flat type silicon solar cell, V-grooved Si-cell without Microlens and V-grooved Si-cell with Microlens have been carried out under controlled air mass conditions. The cell temperature has been varied with very good accuracy due to the mechanisms of the test setup. The operating cell temperature plays an essential role in the photovoltaic conversion process. The influence of operating cell temperature on cell performance is investigated by performing experiments where the cell is systematically varied. In order to create a base for comparison of the results achieved from the tests at any irradiance, linear regression on the results have been performed with respect to cell temperature for all cells. The various correlations have been proposed to represent simplified working equations which apply to modules mounted on free-standing frames. For specific cells tested, the influence was positive for DSSC with an increase up to 40 % of efficiency at standard test condition while a decrease in efficiency of approximately 16 % was seen for the silicon solar cells In this investigation, combined heat transfer in a photovoltaic panel/wall has been reported. The photovoltaic panel/wall is a model, which is composed of two pieces of PV panels and a rear side board, and part of the light of radiation energy from the indoor lamps can be converted into electricity. Through theoretical and experimental, the performance of such a photovoltaic panel/wall has been studied. For the convenience of the treatment of heat radiation, a model in terms of the integration of the absolute temperature has been proposed for the numerical simulation of the combined heat transfer in the test panel/wall. By comparison, it is found that with regard to the thermal radiation of lamp surface, good agreement between the results of simulation and experimental data is obtained.