Effects of solar photovoltaic panels on roof heat transfer
Dominguez, A., Kleissl, J. and Luvall, J. C.
2011 Solar Energy, 85(9): 2244-2255
Building energy use; Cooling load; Photovoltaic; Roof heat flux; Thermal infrared camera
Dominguez, A., Kleissl, J. and Luvall, J. C., (2011), "Effects of solar photovoltaic panels on roof heat transfer", Solar Energy, 85(9): 2244-2255.
Abstract:
Indirect benefits of rooftop photovoltaic (PV) systems for building insulation are quantified through measurements and modeling. Measurements of the thermal conditions throughout a roof profile on a building partially covered by solar photovoltaic (PV) panels were conducted in San Diego, California. Thermal infrared imagery on a clear April day demonstrated that daytime ceiling temperatures under the PV arrays were up to 2.5 K cooler than under the exposed roof. Heat flux modeling showed a significant reduction in daytime roof heat flux under the PV array. At night the conditions reversed and the ceiling under the PV arrays was warmer than for the exposed roof indicating insulating properties of PV. Simulations showed no benefit (but also no disadvantage) of the PV covered roof for the annual heating load, but a 5.9 kWh m-2 (or 38%) reduction in annual cooling load. The reduced daily variability in rooftop surface temperature under the PV array reduces thermal stresses on the roof and leads to energy savings and/or human comfort benefits especially for rooftop PV on older warehouse buildings.
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