How Solar Heating Works

Radiant Energy from our sun is probably the worlds greatest potential source of unlimited, natural energy. Solar Power or photovoltaics is the science of capturing energy from the sun and converting it to practical uses. Even after sunlight penetrates our atmosphere and reaches the surface of the earth, each square meter receives about 4.2 killowatt hours of energy per day. That’s the equivalent of just over four barrels of oil!

Solar Heating Collectors

Generally, solar panels are installed on roofs, facing southward, in an area where sunlight is not blocked (solar panels are of course unable to perform in the shade). Generally, roof panels (also called ‘collectors’) are designed with dark, non reflective colors, and made of materials which maximize the efficiency of the unit, passing the heat from the sun, to the water. Pipes move the cold water into the collector (or solar panels), heating it, and then other pipes move the heated water into insulated storage tanks where the water may then be used on demand.

Below: A typical commercial solar hot water heating system.

Types of Fluids Used

In warm areas, water is the only liquid required, however in colder climes, where pipes are at risk of freezing, a water glycol mix (anti-freeze) is normally used to be sure the water may keep flowing, even in the coldest temperatures. In some cases, a heat-transfer fluid is used, which heats the water with methods very similar to that of either an electric or gas heater.

Solar Power Heating Costs

Generally, a solar water heating system costs between $1,500 and $3,000, not including installation. Although this is more expensive than a traditional water heater, there are still great potential cost savings, because a solar water heater can cut water heating costs anywhere from 20% to 40% (or even as much as 90% in some southwestern areas).

Tax Credits, and Water Cooling

Generally, there are many tax credits available for solar water heating systems (for example, EPA approved systems may be eligible for tax credits). Another interesting fact is that solar power can also be used to cool water in addition to heating it.

Below: this parabolic trough solar commercial solar hot water heating system provides 50% of the hot water needs for the Jefferson Country jail in Golden Colorado.

Conclusion

For many, preserving the environment and cutting down fossil fuel usage is more than enough reason to install a solar hot water system. In the long term, installing a Solar Hot Water system is also beneficial due to cost savings from reduced monthly water heating bills. Generally cost savings range from 20-40% monthly, although there are cases recorded where cost savings have reached as much as 90% monthly. The first solar panels had efficiency levels of just 1-2%, while modern day panels (as of 2009) have efficiency as high as 8% or more. Along with expected improvements in both production costs, and energy output, most likely Solar Hot Water Systems will become more popular in the years to come.

Find a Solar Hot Water contractor.