Tuesday, October 5, 2010

Solar Hot water collector panels.

If you live in a rural area with severe frost should you choose a solar hot water system with water filled flat panels or evacuated tubes?

This is a commonly asked question by nearly every person looking to purchase a solar hot water system regardless of whether they live in town or out of town.

At 6 Star Hot Water and Plumbing Canberra our experience has shown that there is no real difference between the water filled flat panels and the evacuated tube solar hot water systems.

Both types of hot water systems have an electronic frost protection function. This function is set to automatically turn on the small solar pump which normally circulates water from the solar collectors into the solar storage tank. This is based on the principal that flowing water will freeze at a significantly lower temperature than static water.

This circulating water protects the collectors and the solar circulating pipes between the collectors and the solar storage tank from freezing.

The electronic frost protection system also allows the warmer water from the base of the solar hot water storage tank to circulate through the pipes and collectors.

Because evacuated tube systems only have electronic frost protection the solar circulating pipes between the collectors and the solar storage tank are more susceptible to freezing. Freezing in the solar circulating pipes will occur if any one of the circulating pump, solar control pad or sensors malfunction. In particular, cockatoos like chewing through the sensor wire connected to the collector sensor.

However, this does not mean that evacuated tubes are less suited to rural areas than water filled flat panel collectors.

Water filled flat panel connectors require a secondary frost protection system as a backup for the electronic frost protection system. Though, this is does not always help.

The secondary frost protection system on a water filled flat panelled system relies on water pressure to prevent the panels from freezing and cracking.

The secondary system required for a flat panelled system in frost prone areas is called an anti frost valve. The anti frost valve opens to let water, which is pressurised by your domestic pressure pump, to flow through the panels and onto the roof surface when the water in the panels drops below 2 degrees Celsius. This is likely to occur if the circulating pump, solar control pad or sensors malfunction. The anti frost valve’s purpose is the based on the same principles as the electronic frost protection function.

However, if you live in a rural location and you rely on an electric pump for your domestic pressurised water, you could find yourself in big trouble. Especially if you get a heavy frost and a blackout at the same time.

While the anti frost valve may open during a blackout, your electronic frost protection will not work and your domestic pressure pump will not supply pressurised water to the panels. Therefore the water in the panels will be static. Not only can your panels freeze and crack so can your solar circulating pipes.

If you would like more information to help you choose a solar hot water system you can contact 6 Star Hot Water and Plumbing.

Just follow the links for installing solar hot water systems within Canberra rural regions.

Ask us for a quote on line or speak to a qualified tradesman now by calling 61619417