Solar Hot Water
One of the most cost-effective ways to include renewable technologies into a building is by incorporating solar hot water. Most systems can pay for themselves in 2 - 3 years. Solar water heaters use the sun to heat either water or a heat-transfer fluid in the collector. Heated water is then held in the storage tank ready for use, with a conventional system providing additional heating as necessary. The tank can be a modified standard water heater, but it is usually larger and very well insulated. Solar water heating systems can be either active or passive, but the most common are active systems.
Click here for a detailed document explaining the different systems and their applications.