Solar Thermal Systems
Solar Thermal systems may be broadly split into three categories: Water heating, swimming pool heating, and space heating or cooling. Each utilizes variations on one simple technology: heating a thermal storage medium with solar energy. This storage medium may be used directly, as is the case with open-loop water heating, or indirectly, as in a heat exchanger.
Solar-thermal systems offer a very compelling economic rationale, with relatively low initial capital costs and relatively fast payback. There are two types of solar hot-water systems: Active Systems and Passive Systems.
Overview Active Systems Passive Systems Page 4