Energy-efficient solar shade system for skylights

Abstract

An energy saving skylight cover system operates selectively in summer and winter to optimize transfer of the sun's radiation through the skylight into an interior space. The skylight cover system comprises optical transmission modifying panels and radiation scuppers that make its functional characteristics responsive to the sun's incidence angle. In summer mode, with high average inclination of the sun, the skylight cover system absorbs or reflects back the undesirable solar heat. In winter mode, the skylight cover system permits majority of the sun's rays to enter the interior space, permitting desirable solar heat gain. The determination of rejecting or accepting solar heat gain is made by the skylight cover system according to a designed-in characteristic angle. The characteristic angle is a function of the orientation of the skylight and the roof, and the geographical location of the building. For manufacturing cost-effectiveness, a finite set of skylight cover pane designs with predetermined characteristic angles is selected. The radiation modifying panels consist of one or more diffraction gratings, with additional spectrally selective and angle-selective coatings and materials for selective rejection and transmission of ultraviolet, infrared and visible portions of the solar radiation to provide maximum energy efficiency combined with optimum thermal and optical comfort of the building occupants.