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This content will become publicly available on January 9, 2019

Title: Reducing Operating Temperature in Photovoltaic Modules

Reducing the operating temperature of photovoltaic modules increases their efficiency and lifetime. This can be achieved by reducing the production of waste heat or by improving the rejection of waste heat. We tested, using a combination of simulation and experiment, several thermal modifications in each category. To predict operating temperature and energy yield changes in response to changes to the module, we implemented a physics-based transient simulation framework based almost entirely on measured properties. The most effective thermal modifications reduced the production of waste heat by reflecting unusable light from the cell or the module. Consistent with previous results and verified in this work through year-long simulations, the ideal reflector resulted in an annual irradiance-weighted temperature reduction of 3.8 K for crystalline silicon (c-Si). Our results illustrate that more realistic reflector concepts must balance detrimental optical effects with the intended thermal effects to realize the optimal energy production advantage. Methods improving thermal conductivity or back-side emissivity showed only modest improvements of less than 1 K. We also studied a GaAs module, which uses high-efficiency and high-subbandgap reflectivity to operate at an annual irradiance-weighted temperature 12 K cooler than that of a c-Si module under the same conditions.
ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [3] ; ORCiD logo [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States). National Center for Photovoltaics
  2. Univ. of Toledo, OH (United States). Wright Center for Photovoltaics Innovation and Commercialization (PVIC)
  3. Univ. of Minnesota, Minneapolis, MN (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2156-3381
Grant/Contract Number:
Accepted Manuscript
Journal Name:
IEEE Journal of Photovoltaics
Additional Journal Information:
Journal Volume: 8; Journal Issue: 2; Journal ID: ISSN 2156-3381
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
14 SOLAR ENERGY; computer simulation; optics; photovoltaic cells; photovoltaic systems; ray tracing; solar energy; solar panels; thermal conductivity; thermal management
OSTI Identifier: