Free standing photovoltaic module(s) were investigated, how the flow field and the heat transfer coefficients arise in this case. Free standing modules are used in many cases where big arrays are planted, and its very similar to modules mounted on large flat roofs. The efficiency of photovoltaic (PV) devices is decreasing as the modules temperature increasing thanks to that part of the solar irradiance which is not converted into electricity. The placement of the PV modules has a big affect on the natural cooling, due to wind flow-around and the buoyancy driven flows. The effect of the environmental parameters (temperature, irradiation, wind) on the performance on one type of PV module with dimensions 1245 × 637 × 10 mm in terms of the cell temperature and heat transfer coefficient has been determined numerically. In view of the flow field and the heat transfer, which was calculated numerically, the heat transfer coefficients can be determined. Five inflow rates were set up to let the trend of the heat transfer coefficient know, while this function can be used for the Matlab/Simulink model. It has been found that under a constant solar heat gain, the air velocity around the modules is increasing, proportionately to the wind velocities, and as result the heat transfer coefficient increases linearly, and can be described by a function.