Moreover, an active ventilation concept with fans assures air circulation inside the platform and keeps the inner temperature equal to the room temperature. A fan in the lower section blows air into the platform, another one takes air out from top of the platform. This configuration assures a continuous air circulation from bottom to top. Since the lighting sources are mounted on top of the platform, this direction of circulation minimizes the heat transfer from light sources to the PV cells and measuring devices which are in lower levels.