Families and members at Air force Base Makhado, Limpopo, are reaping the benefits of yet another energy efficiency project – this time, solar geysers designed to reduce the damage of limescale build up and the amount of electricity used to heat water in domestic housing. Piloted as one of the projects implemented through a five-year partnership between the South African National Energy Development Institute (SANEDI) and the military, this installation is part of ongoing research to ensure sustainable energy as well as quantify energy, cost and emissions savings through energy efficient and renewable energy interventions.

Certain parts of South Africa are more prone than others to severe limescale build up on water heating systems, and many consumers are unaware that this raises the costs of heating (electricity) and significantly reduces energy efficiency as well as the lifetime of the hardware.

Parts of Limpopo’s natural environment contributes to this issue where “hard water”, containing high mineral content, builds up in geyser and piping hardware that then require more electricity to heat the water. In addition to affecting a geyser’s efficiency for example, the build up eventually damages the geyser and heating element and thus reduces their lifespan. “What you find is that a geyser that should last for five years, is now only lasting eighteen months or less. The SANDF are helping us build a business case for this technology in high lime scale water areas,” says Dr Karen Surridge who is Acting General Manager Energy Efficiency at SANEDI. The project has kicked off with the installation of 50 indirect high pressure solar water heating systems and seven artisan soldiers were trained to install and maintain these systems.

Surridge says the high pressure indirect system specifically deals with lime scale risks to household water heating systems. These indirect high pressure solar heating systems will be compared to other heating technologies viz. Instantaneous water heating and heat pumps. All these technologies are considered energy efficient over the traditional electrical geyser.

“If you put in a “normal” direct solar water heating system it will simply calcify with lime scale just like the electrical heating. Indirect systems work by heating a water-glycol mix (similar to antifreeze in your car) which runs alongside the normal water and heats it for use. In hot climates like Limpopo, solar water heaters can reach much higher temperatures than what the thermostat of a conventional geyser will allow, meaning that less hot water is needed for use,”