The number of geysers to use is dependent on the following factors:
Solar ready geysers would replace the amount of electricity geysers normally used. If only one geyser is being used it is recommended to use a slightly larger geyser when using solar hot water heating. Use a 150 litre instead of a 100 litre and so on. This is done in order to have enough hot water at night and early morning without activating the thermostat and using electricity to heat the water when a day of sunshine should heat the water.
Should water underfloor heating be used as well, the capacity of the geysers will be increased. In order to utilize water to heat the floor approximately 5 litres of hot water must be stored for every 1 square meter of floor space. This will allow almost no electricity to be used, but is not cost effective as a large quantity of water is being heated during spring, summer and autumn that is not being used. The number of geysers being used is also dependant on the area being heated, and the number of geysers normally being used for domestic heating.
The positioning and installation of the geyser are best done as follows:
- Unlike electrical geysers which are normally installed in different areas in the house to cater for different bathrooms, kitchen etc, solar geysers are best installed in the same area close to the solar collectors.
- The geysers are also best installed in series with the hot water from the solar collectors flowing into the first geyser. The bottom of the first geyser is then connected to the top of the next geyser and so on with the last geyser feeding back to the solar collectors. The hot water inlet to the house is taken from the first geyser and the municipal cold water inlet is connected to the last geyser.
The advantages of the above are as follows:
- The first geyser will always be the hottest as the solar collectors first feed into this geyser and once hot will heat the next geyser in series. The water for the house is being drawn from this geyser.
- When hot water is being used in the house from the first geyser the water is being replenished from the next geyser in series with only the last geyser mixing with municipal cold water.
- A hot water ring feed may easily be added. This is recommended in a large house but can be used in any house.
The type of storage unit/geyser recommended for use:
Solar geysers vary from 80 litres, 100 and increments of 50 litres to 500 litres. We recommend using W.E. Geysers with a pex lining that cannot corrode, has no artificial anode, is SABS approved and has a 10 year guarantee, or an X-stream geyser, which is fibreglass, and has a 5 year guarantee.
Large houses may need large storage tanks for example 1200 litres or more, which are available and are specially constructed. Using 4 X 300 litre geysers are easily available and the system will still function should one geyser malfunction which is not the case with a single tank. There is very little price difference between using one large tank or 4 smaller tanks. The large tanks don't have an extended guarantee.