Comprehensive analysis and general economic-environmental evaluation of cooling techniques for photovoltaic panels, Part I: Passive cooling techniques

This paper deals with the analysis of passive based cooling techniques for photovoltaic panels (PVs). A comprehensive review and evaluation of the research activities and in general studies related to the development of passive cooling techniques for PVs was obtained. A major contribution to the herein reported research study is the provision of a general economic analysis for the passive cooling options as there is a gap in present research studies related to the economic aspect of the proposed cooling techniques (the same issue was also noticed for environmental aspects). Based on the comprehensive literature review, it was found that most of the examined passive cooling options are ones with an assumed application of PCM, then air based, liquid based (water, nanofluids, etc.) and finally radiative based. A 30 kW PV plant case study was considered in order to estimate the LCOE for each considered passive cooling technique, i.e. to examine the economic aspect (where general performance data were used with respect to the obtained analysis of the passive cooling techniques). Furthermore, LCA was also carried out in order to check the environmental aspects of the considered passive cooling techniques for PVs. Finally, according to the gained results and existing technical solutions, the currently most viable passive cooling option, both from a technical and economic point of view, is the air based cooling option with Al-fins mounted on the backside surface of the PV panel. The PCM based passive cooling technique for PVs could only be an option in future terms if a significant PCM material price drop were to occur. Therefore, the future development of passive cooling techniques could be focused on the research of hybrid cooling options. The hybrid passive cooling option assumes a mix of passive cooling techniques. Finally, the advantage of each cooling technique could be efficiently utilized in that manner.