Solar Panels?

[JonathanRackham]

If solar panels are put on a building and convert that energy, do the cooling requirements of the building go down?

Have any studies been done?

Serious thermodynamic question.

[FBaggins]

1. Yep!

Solar panels can definitely reduce cooling needs by shading the building beneath them... just like trees that shade a home help reduce cooling costs.

Unlike deciduous trees (that fail to shade a home from the sun in winter), they would also reduce the amount of heat that the home picks up from the sun in winter, but the net effect should be positive.

Some solar installers used to claim that it was the equivalent of a 5% discount on the price of the solar panels... but of course your mileage will vary.

Here's a study that I found when looking for an example of that 5% claim:
http://inhabitat.com/study-discovers-that-solar-panels-have-a-cooling-effect-on-buildings/

[OKIsItJustMe]

2. Scientific study

http://dx.doi.org/10.1016/j.solener.2011.06.010

[font face=Serif][font size=5]Effects of solar photovoltaic panels on roof heat transfer[/font]
…
Received 19 July 2010, Revised 8 June 2011, Accepted 11 June 2011, Available online 6 July 2011

[font size=4]Abstract[/font]

[font size=3]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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