Solar water heating: an overview
Solar water heating systems generate hot water using energy from the sun. The sunshine in South Africa is ideal for solar water heating, and is capable of providing alternative energy solutions to millions of households, generating enormous savings in energy costs.
Solar water heaters
There are two categories of solar water heaters: indirect and direct systems. An indirect solar water heater uses a heat transfer liquid to transfer heat from the solar panels to the geyser. An indirect solar water heating system works well in South Africa as it is freeze-resistant and capable of withstanding frost and below zero temperatures. Direct solar water heating systems should only be used in frost-free regions, such as Cape Town in South Africa and other coastal areas. The advantage of a direct solar heater is that it requires very little maintenance.
Solar water heating systems are comprised of a solar geyser, solar panels, solar battery and heat transfer liquid or a pump.
Solar water geysers and panels
A solar geyser, as used in solar water heating systems, is well insulated, so hot water stays hotter for longer than in conventional geysers. You can get an Eskom rebate when you purchase a solar geyser from approved Eskom solar water heating suppliers. Kayema is an Eskom approved solar water heater supplier and offers professional solar geyser installation so that you don’t have to try the DIY route.
Two types of solar panels are recommended for use in residential solar water heating systems: flat plate solar panels and evacuated tubes. Flat plate collectors are more common in solar water heaters in South Africa and their lifespan can be counted in decades.
Active and passive solar water heating systems
Solar water heating systems can be either active or passive. Active solar water heating systems can be further sub-divided into direct and indirect circulation systems. Direct solar water heater systems use pumps to circulate water through the heating system; indirect systems use pumps to circulate a heat transfer liquid through the collectors and a heat exchanger and into the home.
A passive solar heating system may be less expensive than an active system, but that’s because passive systems are generally not as efficient as their active counterparts. Passive systems can also be sub-divided into integral collector-storage systems, which work best in temperate climates and thermosyphon systems, which rely on the principle that warm water rises and cooler water sinks. Thermosyphon solar water heater systems are efficient as long as the collectors are above the geyser, if not your water will never be hot enough.
There are DIY methods to build your own solar heater or solar heating system, but many people in South Africa have found to their detriment that DIY solar water heaters aren’t nearly as efficient as their professionally constructed competitors. The prices of do-it-yourself solar water heating systems may be friendlier but they also tend to be problem prone and you won’t benefit from the advice and service provided by expert solar geyser and panel installers.
Kayema’s solar water heaters
Kayema provides top-of-the-line solar water heaters and solar thermal systems that will efficiently heat your household’s water for decades to come. Kayema’s solar water heating products and services adhere to international standards and are recognised all across South Africa and around the world. In addition to qualifying for the Eskom solar rebate when you purchase your solar geyser, you can also rest assured that Kayema is an Eskom DSM partner and, as such, is dedicated to ensuring a greener, cleaner South Africa.
