13VAC5-200-110: Passive solar energy system defined

An assembly of natural and architectural components including collectors, thermal storage device or devices and transfer medium which converts solar energy into thermal energy in a controlled manner and in which no fans or pumps are necessary to accomplish the transfer of thermal energy. Fans may be used to assist the natural convective air flow in a passive air heating system. The prime element in a passive solar system is usually some form of thermal capacitance.