Water Heating

Solutions

water 
heating Solutions

The geyser is by far one of the biggest electricity guzzlers and installing a heat pump or solar water geyser can dramatically reduce your energy consumption, save you thousands of Rands over the years on your electricity bill and make a significant contribution to ‘greening’ your home or business. Furthermore, if you have plans to generate your own electricity by means of photovoltaic solar power (PV), you need to work towards getting your property ‘PV-ready’ and reducing your electricity usage – the geyser is a primary starting point.

There is no right or wrong answer and your decision will depend on a number of important considerations that One Energy will discuss with you based on your specific needs analysis. Both solar and heat pump technologies have vast energy efficiency and environmental benefits and are complementary technologies on saving energy.

Solar Geyser of Heat Pump

Your choice will depend on the projected savings and thus payback period you require, your motivation for updating your method of heating water, your usage as well as the site and technical aspects of the installation.

One Energy offers a range of products across both heat pumps and solar geysers and we’ll do a thorough needs analysis to help you to weigh up the alternatives and make the right choice.

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How does 
a Solar Geyser work?

Solar water heaters use the radiation from the sun to generate heat. The size of the solar panel will determine how much energy can be collected from the sun. For example if you have a 4sqm or bigger flat plat solar panel connected to a 300L geyser, this should give you 300L of 60°C water at the end of a sunny day. The same applies with an evacuated tube system, whereby the bigger your geyser, the greater the number of tubes you need to heat your water.

During cooler days with less sunshine you may still need a geyser element to supplement your hot water heating usage. Today, solar systems are installed with very smart timing systems which allow you to specify time zones for when you want to have hot water, for example at night between 6pm and 9pm when you take your bath, and again in the morning between 5am and 8am. Your system will work to ensure that you always have hot water during these times to the specific temperature.

If the temp drops to below your specified requirement and there’s no sunshine at that time to reheat it, your system will kick back to the geyser element to supplement your hot water. It will only do this if necessary, so the savings are significant. In fact, a properly-sized solar geyser can cut your monthly electricity bill by anywhere between 30-40% of your total monthly electricity cost.

When going solar, as a rule of thumb, each person in the household uses around 70 litres of hot water a day. Check with your supplier about the size and the power output of the system. An under-sized or low efficiency system will result in insufficient hot water and a poor realisation on electricity savings, defeating the whole purpose of why you bought the system.

How does 
a Heat Pump work?

The heat pump uses a small amount of electricity to extract a lot of the latent heat energy from the surrounding air. So a heat pump is also using the energy from the sun but only indirectly and so it can work day and night, winter and summer. The efficiency of a heat pump is called the Coefficient of Performance (COP). A COP value of 4 means that the heat pump produces four times as much thermal energy as what it uses electrically – in other words a 75% saving on the water heating bill. Using a COP value of 4, a high efficiency 4.7kW heat pump takes about 3 hours to re-heat a 200L geyser from a cold start. This enables you to always have hot water at a fraction of the cost no matter when or how much water you use. Unlike the solar option, a heat pump also requires virtually no change to your lifestyle and routine as it is not limited by the availability of the sun for heating.
Using a COP value of 4, a high efficiency 4.7kW heat pump takes about 3 hours to re-heat a 200L geyser from a cold start. This enables you to always have hot water at a fraction of the cost no matter when or how much water you use. Unlike the solar option, a heat pump also requires virtually no change to your lifestyle and routine as it is not limited by the availability of the sun for heating. The main advantage of a heat pump is the ability to re-heat a geyser a few times per day or night, rain or shine. Heat pumps are suited to facilities that have high-hot water usage where solar heating would not keep up with hot water demands, as well as areas with significant shading where solar panels would not be effective for heating.