Thermal Effects of Microinverter Placement on the Performance of Silicon Photovoltaics
The work was supported by NSF CBET (Grant No. 0853933), PSU Institute for Sustainable Solutions, Oregon BEST, Portland General Electric, and the City of Portland Bureau of Environmental Services. MKS was supported by an NSF REU summer fellowship (Grant No. 1004737) and a Portland State University Innovation Grant.
Typical installation of a microinverter in a plane parallel position on the back side of a monocrystalline silicon photovoltaic (PV) panel can lead to differential heating of the PV cells immediately above the microinverter by as much as 4 °C. Rotation of the microinverter to a perpendicular position allows the microinverter itself to run cooler by about 4 °C and completely removes the distinctive heat signature on the panels. Because the thermal effects of the microinverters are significant for only two of the 72 cells on the panel, changes in DC power output from the panels are not detectable. However, lower microinverter temperatures increase microinverter efficiency by about 0.65%, such that overall AC power production is increased by about 0.09%. In addition to these small improvements to be gained by the repositioning of microinverters, there are also potential long-term concerns that nonuniform heating may lead to accelerated degradation in the affected area of the panel.
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Day, N. U., Reinhart, C. C., DeBow, S., Smith, M. K., Sailor, D. J., Johansson, E., & Wamser, C. C. (2016). Thermal effects of microinverter placement on the performance of silicon photovoltaics. Solar Energy, 444-452.