Solar water heaters
With all the talk of protecting the environment and conserving resources, many consumers are looking to the sun as a natural energy source. One way solar heat can effectively be used in the home is with a solar water heater. These systems, powered most often by flat panels on the roof, provide instant hot water, work in any climate, and can provide 50% to 80% of a home's hot water needs, depending on the season. There are two types of solar water heaters: active and passive. Passive systems use gravity, but more popular active systems use pumps to move heated water between a collector and storage tank. That insulated storage tank means when you turn on the shower in the morning, you'll have hot water right away, heated by the warmth of the sun.
Neville Williams founded Standard Solar, a solar installation company, and says the most common are active systems. They rely on pumps to move the liquid between the collector and the storage tank.
"And you circulate a heat exchanger fluid that goes to two heat exchangers and you have a second hot water tank which preheats your hot water," Williams says. "And these things run at such high temperatures that you'll actually have more hot water than you can use so the question is storing it overnight in a good insulated tank means in the morning you'll have hot water close to boiling so it's really efficient stuff and you can save a lot of money with solar hot water systems."
A well-designed system will provide 50-80% of a home's hot water needs, depending on the time of year. Flat panels on the roof are the typical way to collect the sun's rays. The panels need about six hours of good sunlight.
"You need a south-facing roof and somewhere you can stick it where it's south facing and no shade and that's about it," Williams says. "And sometimes people don't want it on a roof so they'll put it on a shed or even put it out in their yard. And that's a good idea too as long as it's not too far from the house."
Performance varies on how much solar energy is available, but also on how cold the water is coming in. The colder the water, the more efficiently the system operates.
However, don't throw out your conventional water heater. Many building codes require you to have one as a backup.
Radio interview source: Neville Williams, chairman, Standard Solar
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