Model for the thermal characteristics of flat-plate photovoltaic modules deployed at fixed tilt

The thermal characteristics of 11 flat-plate photovoltaic (PV) modules are investigated and modeled against meteorological elements: irradiance, angle of incidence, wind speed, plus air and sky temperatures. Above 500 W/m² irradiance, the ratio of the average difference between module and air temperatures divided by the incident irradiance is constant, and apparently preordained by module construction-ranging 27°-40°C/(kW/m²) in value-suggesting that these thermal characteristics are driven by the incident solar power. When low-irradiance conditions arise under clear-sky conditions, this ratio becomes small and can exhibit negative values. In this regime, the module´s greater reflectance-resulting from larger angles of incidence to the sun-coupled with radiant heat emission dominate the thermal behavior. A new model for the thermal characteristics is presented that accounts for low- and high-irradiance regimes and resolves wind-speed dependence