Solar water heating is a reliable and renewable energy technology used to heat water. Sunlight strikes and heats an absorber surface within a solar collector or an actual storage tank. Either a heat-transfer fluid or the actual potable water to be used flows through tubes attached to the absorber and picks up the heat from it (systems with a separate heat-transfer-fluid loop include a heat exchanger that then heats the potable water.) The heated water is stored in a separate preheat tank or a conventional water heater tank until needed. If additional heat is needed, it is provided by electricity or fossil-fuel energy by the conventional water heating system.
- The avoided cost of energy is high (gas is not available, electricity rates are above $0.034/kWh)
- There is a dependable, consistent hot water requirement (such as enlisted quarters, laboratories, or hospitals)
- There is a reasonably high daily average solar radiation rate on a tilted surface (in excess of 4.5 kWh/m²/day—although if the avoided cost is high enough, solar water heating is effective in most climates)
- Energy security is important (such as on an international base where energy supplies could be interrupted).
Save 40 % on Fual Cost