ABSTRACT
Passive systems are deŽned, quite generally, as systems in which the thermal energy ¡ow is by natural means: by conduction, radiation, and natural convection. A passive heating systemis one in which the sun’s radiant energy is converted to heat upon absorption by the building. The absorbed heat can be transferred to thermal storage by natural means or used to directly heat the building. Passive cooling systems use natural energy ¡ows to transfer heat to the environmental sinks: the ground, air, and sky.
