Solar water heating systems

background

On average, 13% to 26% (17% overall) of energy in a US household is consumed heating water[1].

Heating water using conventional sources of heat contributes significantly to a household's utility bill and green-house-gas (GHG) emissions[2].

Solar water-heating systems significantly reduce the amount of utility power consumed in the process of heating water.

Using solar power to heat water significantly reduces GHG emmisions and saves water heating costs. The more water is heated by the sun, the less conventional energy is used to heat water.

system designs

Heating water by the sun can be as simple as painting a bucket black and leaving it in the sun.

Solar water heating systems work on the same basic principle and consist primarily of these designs:

• passive systems
• active systems
• closed-loop systems
• open-loop systems
• drainback systems - a hybrid that combines the best of open and closed loop designs

There are many variants that accomplish the same result. These may use parabolic troughs, concentrating mirrors, freon or oils as a heat transfer fluid, and vacuum tubes etc.

The majority of solar hot water heating systems installed in the United States are highlighted above. Their popularity is due to cost efficiency and proven performance over decades of use.

1 - according to the US Energy Information Administration (EIA) data.
2 - extrapolated from EIA data with GHG and co2e equivalents from The Climate Trust.