Passive Solar Design

Passive solar design is an architectural approach in which a building's windows, walls, floors and overall form are configured to collect, store and distribute the sun's heat during cold periods and reject solar heat gain during warm periods, achieving thermal comfort without relying on mechanical or electrical equipment such as pumps or fans. Its scientific basis draws on climatology, thermodynamics, the three modes of heat transfer, fluid mechanics and thermal comfort research, and its practical execution requires attention to site latitude, sun path, thermal mass, glazing selection and shading. While sun-oriented building reaches back to antiquity, passive solar design became a formalised, intensively studied discipline following the 1970s energy crisis, when rising fuel costs drove architects, engineers and governments toward heating and cooling strategies independent of mechanical systems. Central to the approach is thermal mass, dense material that absorbs excess solar heat during the day and releases it gradually after sunset, smoothing a building's temperature swings across the full day-night cycle, and since 1979 the practice has been treated as a critical element of the drive toward zero-energy buildings.