Greenergy Solutions

Solar Geysers

Why Solar Water Geysers

Solar Water Heaters systems are designed to deliver hot water for most of the year.
However, in winter there sometimes may not be sufficient solar heat gain to deliver sufficient hot water.
In this case an electric booster (element or heat pump) is used to assist in heating the water to the required temperature of 55 degrees C, which is the optimal temperature.

The type, complexity, and size

of a solar water heating system are mostly determined by:

  • Changes in ambient temperature and solar radiation between summer and winter.
  • The changes in ambient temperature during the day-night cycle.
  • The possibility of the potable water or collector fluid overheating.
  • The possibility of the potable water or collector fluid freezing.

    The minimum requirements of the system are typically determined by the amount or temperature of hot water required during winter, when a system's output and incoming water temperature are typically at their lowest.

Type of Solar Collectors:

Flat plate collectors:

  • They are an extension of the basic idea to place a collector in an 'oven'-like box with glass in the direction of the sun.
  • Most flat plate collectors have two horizontal pipes at the top and bottom, called headers, and many smaller vertical pipes connecting them, called risers. The risers are welded (or similarly connected) to thin absorber fins.
  • The type of glass used in flat plate collectors is almost always low-iron, tempered glass. Being tempered, the glass can withstand significant hail without breaking, which is one of the reasons that flat-plate collectors are considered the most durable collector type.

Evacuated tube collectors:

  • ETC are a way in which heat loss to the environment, inherent in flat plates, has been reduced.
  • Since heat loss due to convection cannot cross a vacuum, it forms an efficient isolation mechanism to keep heat inside the collector pipes.
  • Since two flat sheets of glass are normally not strong enough to withstand a vacuum, the vacuum is rather created between two concentric tubes.
  • Typically, the water piping in an ETC is therefore surrounded by two concentric tubes of glass with a vacuum in between that admits heat from the sun (to heat the pipe) but which limits heat loss back to the environment. The inner tube is coated with a thermal absorbent.
  • Life of the vacuum varies from collector to collector, anywhere from 5 years to 15 years.

Different types of High Pressure Solar Geysers Systems:

  • Thermo siphon systems: Closed couple and split, both can be direct or indirect. Indirect means glycol (heat transferring liquid) is in the flat plate panel and not water. 
  • Closed couple means geyser and panel on roof.
    Split means panel on roof outside, but lower than geyser in roof for the natural process of thermo siphoning to take place: The only moving “part” is the heat transferring liquid or glycol;
  • Pump system: Geyser lower than panel and thermo siphon cannot work. 220V or 12V pump installed to circulate the water/glycol between the panel and geyser, as the natural process of thermo siphon will not take place.
  • Integrated system: Evacuated tubes integrated with the geyser forming a unit. Geyser and evacuated tubes (collector/panel) on the roof;
  • Retrofit: An evacuated tube collector or direct flat plate collector is retrofitted to your existing geyser or a new conventional electrical geyser. The retrofit also needs a pump to circulate the water between the geyser and collector.

The larger the storage vessel (geyser) of any solar geyser, the more electricity you will save as the solar panel/collector heats the water while the sun is shining. The more hot water you store, the less are the chances that the electrical backup element will kick in and/or the element will be on for a shorter time. This will save you electricity. Work on 50 to 70 litres per person on a geyser depending on life style and shower roses (use water saving roses of 9 lt per min instead of the normal roses that allow from 15lt and more per min).


We have access to various products on the market.

Preferred brands of solar geysers installed by Greenergy Solutions :