TECHNOLOGY / 14 OCTOBER 2010, 10:09AM /
Consumers that are shopping around for a solar heating system in a bid to save money on their electricity bills should be careful to choose a system which is based on the right technology for South African conditions and is provided by a reputable supplier with a long track record in solar water heating.
That’s the word from Graham Mundy, founder and managing director at Solar Beam, a pioneer of South Africa’s solar water heating solutions market. He says that the South African market for solar water heating systems has exploded following the country’s 2008 power crisis and a pledge from Eskom to provide rebates to consumers who install accredited solar water heating systems.
Where there were once only eight or nine companies supplying solar water heating solutions in South Africa, there are now more than 500, many of them without the experience or technology needed to provide a sound solution to business and residential customers. Many of these organisations are importing products from Europe or Asia that are a poor fit with South African conditions, Mundy says.
Mundy recommends that consumers opt for a solution based on flat-plate technology, a proven technology that has a track record of more than 30 years in South Africa. Many companies are trying to sell solutions based on glass tubes into the market, which are not ideal for South African weather conditions, he adds.
Glass tube solutions were developed for European conditions and are most effective when temperatures above 70 degrees Celsius are required. Flat plate solar collectors are more robust than glass tube systems and can more easily withstand adverse weather conditions such as hail. Glass tubes are more fragile and may be damaged during the transport or installation process.
Mundy also cautions consumers against “retrofitted” solutions, where a solar panel is simply connected to an electric geyser. The quality and performance of a retrofitted solution will not be up to the level offered by a dedicated solar system.
According to Mundy, “There are so many reasons that connecting a solar panel to an electric geyser is such a bad idea that no one should even consider it. One of the major reasons is the lack of hot water storage volume. An electric geyser using its element, can cycle its contents every three hours, whereas a solar system needs to store the volume of hot water required over 24 hours for the family’s daily use.
“Therefore, the equivalent solar water heater for the same family should be double the volume, i.e. 300 litres. By using the 150 litre geyser as a solar geyser, once the 150 litres of solar heated water is finished, the retro-fitted system is now totally reliant on the electrical element input. The savings will therefore be vastly reduced in comparison to the use of a dedicated solar water heater.
“So the question arises, for the sake of a few thousand rand purchase saving, your long term performance loss far exceeds this saving. A standard geyser is also 25 percent less efficient in terms of insulation than a solar geyser.”
Mundy adds that problems with retrofitted solutions have given the solar industry a bad name because the insulation and volume problems produce such disappointing results.
“After having 35 years of industry experience, if this was a durable, long-term and cost effective solution, I would have advocated it. Unfortunately this is not the case”, says Mundy.
With the power crisis and electrical price hikes, there are numerous interventions offered by various companies claiming to reduce your electricity consumption. Of all these interventions, solar water heating is the only method that is not 100 percent electrically reliant, meaning that once the initial purchase price has been paid, most of your water heating bill will be free.
Mundy recommends that consumers work only with solar heating companies that have an SABS Mark of Approval and a track record in the market. An SABS Mark of Approval is quite different to an SABS Compliance Test Certificate and gives extra level of peace of mind.
Concludes Mundy: “With the ongoing electricity supply crisis in South Africa, we all have a part to play in conserving energy. Installing a good solar water heating system is an excellent way to conserve energy. Between the Eskom rebate solar water heating systems and estimated cost-savings of, in some cases in excess of 30 percent a year on electricity, installing a solar water heating system is also a smart way to save on your power costs into the future.”
As electricity prices soar, Eskom’s rebate programme makes the prospect of a solar water heating system even more attractive. The rebates are issued in cash to the consumer by Eskom once an SABS solar system has been installed, and are calculated according to the amount of power the system saves the user in heating water.