Control of heat transfer and radiant energy flow through building apertures is essential for maximizing thermal and daylighting benefits and minimizing undesired heating and cooling loads. Architectural solutions based on current technology generally add devices such as louvers, shutters, shades, or blinds to the glazing system. This paper outlines the objectives and accomplishments of a research program the goal of which is to identify and evaluate advanced optical and thermal technologies for controlling aperture energy flows, thus reducing building energy requirements. We describe activities in four program areas:
- low-conductance, high-transmittance glazing materials (e.g., low-emittance coatings, aerogels);
- optical switching materials (e.g., electrochromic, photochromic);
- selective transmitters; and
- daylight enhancement techniques.