ABSTRACT
Passive systems are dened, quite generally, as systems in which the thermal energy ow is by natural means: by conduction, radiation, and natural convection. Passive features increase the use of solar energy, ambient conditions, and earth and deep space to meet the heating, cooling, and lighting loads of buildings. For example, window placement can enhance solar gains to meet winter heating loads, provide daylighting, or do both. Using a solar chimney to draw air through a building directly or via an earth air tunnel is an example of passive cooling.
