Improvement of PV module optical properties for PV-thermal hybrid collector application

• Published in: Solar energy materials and solar cells Vol. 95; no. 8; pp. 2028 - 2036
• Main Authors: Dupeyrat, Patrick, Ménézo, Christophe, Wirth, Harry, Rommel, Matthias
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-08-2011; Elsevier
• Subjects: Accumulators; Applied sciences; Collectors; Crystalline silicon solar cell; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Encapsulation; Energy; Engineering Sciences; Exact sciences and technology; Hybrid solar collector; Mechanics; Miscellaneous; Modules; Natural energy; Optical properties; Photoelectric conversion; Photovoltaic conversion; Photovoltaic module; Photovoltaic/thermal; Physics; Solar cells. Photoelectrochemical cells; Solar collectors; Solar energy; Solar thermal conversion; Thermal efficiency; Thermics; Encapsulation; Hybrid solar collector; Photovoltaic/thermal; Photovoltaic module; Crystalline silicon solar cell; Performance evaluation; Silicon solar cells; Solar collector; Absorbent material; Thermal behavior; Photovoltaic system; Solar hybrid technology; Standards; Crystalline material; Thermal properties; Test facility; Optical properties; Solar energy; Photovoltaic array; Thermal efficiency; Stratification; Current density; Comparative study
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2011.04.036

Photovoltaic-thermal collectors (or PV-T collector) are hybrid collectors where PV modules are integrated as an absorber of a thermal collector in order to convert solar energy into electricity and usable heat at the same time. In most of the cases, the hybrid collectors are made by the superposition of a PV module on the thermal absorber of a solar collector. In this paper, the approach is different and is to analyze thermal and optical properties related to both PV and solar thermal functions in order to identify an optimum combination leading to a maximum overall efficiency. Indeed, although these two functions do not exploit the same range of radiation wavelengths, thermal and PV functions are not so complementary due to photo-conversion thermal dependency. In this context, an alternative PV cell lamination has been developed with increased optical and thermal performance. The improvements were evaluated around 2
mA/cm
2 in terms of current density in comparison to a standard module encapsulation. Based on this technique, a real size PV-T module has been built and tested at Fraunhofer solar test facilities. The results show a global efficiency of the PV-T collector above 87% (79% thermal efficiency plus 8.7% electrical efficiency, based on the absorber area).
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► PV-T collectors convert solar energy into heat and electricity. ► We developed an adapted solar cell encapsulation technique for PV-T. ► We measured 2
mA/cm
2 increase in current density in comparison to a conventional PV module encapsulation. ► We built a PV-T collector based on this improved technique and we tested it. ► The results show a global conversion efficiency of the PV-T collector above 87%.