Solar Control

In 2005, the energy use from buildings accounted for 39.6 quads, or 39% of total U.S. primary energy consumption. Of that total, 20.5 quads (52%) were due to the three largest energy end uses: heating, cooling, and lighting. In California, not only does cooling represent 15 percent of the electricity use in commercial buildings, it is also the largest end-use component during periods of peak electric consumption—hot summer afternoons—according to the 2006 California Commercial End-Use Survey. Whether nationally or in California, judicious use of shading can reduce perimeter-zone energy use and peak electric demand. And for very low or zero net energy use that relies on radiant cooling systems or natural ventilation, shading systems can control perimeter zone loads below the maximum 4 watts per square foot floor load to ensure that comfort conditions are met.

If window and skylight systems were optimized for both solar control and daylighting, a significant fraction of this energy use could be reduced in perimeter zones and the top floors of buildings. LBNL researchers are working with industry to characterize, develop, and evaluate the performance of advanced solar control technologies that can provide an average annual, seasonal, or real-time response to the space conditioning and lighting demands at the perimeter zone while meeting occupants’ comfort and view requirements.