Solar water heating is efficient, eco-friendly and economical. It’s an investment that offers immediate costs savings and good long-term returns. Install a solar water heating system in your home, and you’re also guaranteed a consistent supply of hot water, round the clock and irrespective of Eskom power outages.
How solar water heating systems work
A solar water heating system consists of a roof-mounted solar panel containing a network of tubes that are filled with water and connected to a holding tank via an inlet and outlet valve.
As the cold water circulates through the tubes, it’s heated by the sun’s rays and flows back into a heavily insulated tank.
The best solar water systems have an electrical back-up that automatically kicks in on cold, cloudy days so that you’re guaranteed hot water even if there’s no sun.
Solar water geyser guide
Different types and configurations of solar water heating systems are available, and each has specific pros and cons. Below we offer a simple guide to solar water geysers and associated terms you might encounter when researching your options.
Direct solar heating systems
A direct or open-circuit solar heating system circulates water directly between the storage tank and the collectors. It’s the ideal solution if you live in an area of South Africa that has a moderate climate and a “soft” water supply – that is, water with a comparatively low concentration of calcium carbonate.
Best for: moderate conditions; soft water supply
Indirect solar heating systems
An indirect or closed-circuit system has a heat exchange system that transfers the heat from the collector circuit into the tank using a heat transfer fluid.
This is a robust system that prevents the build-up of lime scale in the tubes and can withstand freezing conditions. As a result, it’s the best system for homes supplied with “hard” water (water high in dissolved minerals) and those located in South Africa’s high-altitude interior, where frost occurs in winter.
Best for: extreme weather conditions; hard water
Flat-plate or evacuated solar collectors?
There’s a choice of two collector types – flat plate or evacuated solar collectors.
A flat plate collector consists of a cover made from hard-wearing toughened glass, a durable coated metal absorber plate and weatherproof casing. It’s flexible, resilient and affordable and can withstand extreme heat.
Best for: north-facing roof aspects with full sun
Evacuated or vacuum tube collectors are a network of connected tubes. As there’s no protective casing, the tubes can crack more easily. On the positive side, evacuated tubes generate more hot water, especially in cold conditions.
Best for: roofs with limited sun
Close-coupled or split solar system?
Last, you can select a close-coupled system, which has the tank located horizontally just above the collector panel, or opt for a split system and hide the tank under your roof.
A major benefit of a close-coupled solar system is that it circulates the water using the thermosiphon effect, a natural method of passive heat exchange that doesn’t require electricity to function.
A split system has advantages too – it retains heat more effectively and is more aesthetically pleasing. However, it’s more expensive to install and maintain.
Avoid the Eskom blues: get a solar heating system
The prospect of power outages, coupled with alarming increases in Eskom’s electricity tariffs, have prompted more and more South Africans to invest in solar water geysers.
Investing in a solar water geyser in South Africa can have these benefits:
- savings of roughly 25 percent on your monthly electricity bills
- for a four-person household using a 200-litre solar heating system, a real savings of R5,000 or more per year
- a system with a lifespan of 15 to 20 years; equal to that of an Eskom power station.
- access to consumer-friendly financing options
- a constant supply of hot water
- a full return on investment (ROI) within three to five years
- a better ROI than any other renewable energy generating or savings technology
- a very low carbon footprint.
Turbovent specialises in providing affordable, efficient heating and cooling systems – including solar water geysers and other solar systems – to South African homes and businesses. Contact us online or call 0860 266 537 to find out more or discuss your needs.