Technical-economic study of cooled crystalline solar modules

Methods of cooling monocrystalline and polycrystalline solar modules with water vaporizing are analysed in the paper regarding the effects of temperature on performance and its economic relations. Since water usage may present a significant cost the aim of the research was to create a cooling system that operates without loss of flowing water. Results are evaluated from technical and economic points of view in relation to several countries based on systems with 5 kW capacity. Ideal setting of spray heads at 2 bar pressure was achieved with a distance of 0.26 m between the spray heads. In our experiment, a temperature following procedure was tested manually. Due to this procedure, the surface of the module can be cooled with an average temperature value that is calculated after cooling, depending on the temperature of the control solar module. Analysing the daily data of monthly production the number of "ideal days" in a given month were estimated. Comparing the temperature decrease as a result of vaporization measured in summer and in autumn showed no significant difference. The results achieved confirm the connection between temperature change and efficiency change of monocrystalline and polycrystalline solar modules (0.5%/1 degrees C), discussed in previous scientific literature. Effective application of solar module cooling systems is around 10-15% more expensive than the cost of systems without cooling. In general, under current economic conditions the operation of cooled solar modules is viable mainly in South European countries. (C) 2016 The Authors. Published by Elsevier Ltd.