Solar Water Heating has been used for hundreds if not thousands of years to heat water.
Various technologies have been employed in pursuit of the ideal system, balancing efficiency with low maintenance and long service life.
Flat plate systems have been in service for more than 40 years and have proved to befairly efficient in hot climates. They do however require specialist installation and regular maintenance such as regular anti freeze replacement. They are also very inefficient on cloudy and misty days
Evacuated Tube systems are even more efficient and work well in cold climates, but tend to overheat in our climate. They can be used in direct systems, ( where the hot water
used is circulated in the collector vs the indirect system where the water used is separated from the water that is heated) . However coupled with the mostly hard water occurring in Namibia and the propensity to overheat, the collector and pipes tend to calcify in a very short time. They are also prone to lose their efficiency in cloudy and misty weather.
Solar PV heating has been tried for some time , but the high cost of solar panels in the past has precluded serious research into the viability of this system.
However now that the price of panels has fallen dramatically this system is now a viable alternative.
However it does not work if you simply connect your electric geyser element to solar panels, as you will not obtain anything like the potential power output of the panels and also have no way of switching off the panels when the water has reached its desired temperature
In order to obtain the maximum solar energy from the panels a specialised electronic regulator and heating controller is required .
We have now developed a small efficient controller which can do this .
It incorporates an electronic thermostat and display unit which completely automates the heating function and limits the solar heating to the maximum set point and can also automatically switch to AC power if extra heating is required at night.
For more info on the system click on the Solar PV heating Tab under the water heating heading