subject: Solar Geyser FAQ for Home Installations [print this page] Solar Geyser FAQ for Home Installations Solar Geyser FAQ for Home Installations
How soon can I pay back my Green Power solar water heating system through my electricity savings?
Every client is unique with different energy consumption habits and water usage. Eskom claims that your water geyser consumes about 40 to 60% of your monthly energy bill.
From our experience, if your monthly electricity bill is R600 per month and electricity tariffs continue to rise by 15% per annum, you should pay back a 150L system in less than 5 years through accumulated savings.
What happens if the weather is very bad?
Vacuum tube solar water heating is the leader in solar heating technology, operating very effectively even in cloudy and overcast conditions. Vacuum tubes use the light radiation from the sun. For e.g. if you go to the beach and it's overcast you still burn, the same principle applies with the vacuum tube. If the weather is constantly "bad" there are electric backup elements installed in your geyser for those rare "weeks of continuous rain and poor weather".
How hot does the water get in a solar geyser?
This is dependent on the amount of light UVA/UVB radiation but the water can reach temperatures of up to 97o C in summer & 70o C in winter.
How do you install a solar geyser?
Solar elements can be installed on the face of any North-facing wall or preferably on the roof. Water is pumped from the ordinary 3-port internal geyser, in circulation, over the solar element and returned to the internal geyser. Tiled or corrugated roofs work fine, while flat concrete roofs are ideal. The system is mounted onto the roof with each leg bolted to the beams within. Water proofing by means of flashing and sealants is accomplished relatively easily, because the panels are relatively light.
Can I retrofit a Green Power Solar Water heating solution to my existing geyser?
Yes. There are various valves and fittings on the market to retrofit your existing geyser.
What happens when the power goes off?
Nothing. The water gets heated in the panel and as it's heated, the water pressure increases and pushes the hot water through to the geyser. Additional expansion from the hot water will be relieved by the pressure release valve (PRV). Green Power has researched other alternatives like battery back-up systems and also small PV panels to run the pump and controller. Both options are available on request.
How does a vacuum tube heat the water?
A vacuum in its very basic form is merely a natural insulator, providing for a heat-loss factor of merely 7%. In other words 93% of the radiation that enters the glass tube is retained and transferred to the water. The vacuum (similar to our ozone layer) assists in prevention of radiation and convection. Another example is a flask that you put your coffee in to keep warm. The vacuum tubes use the same principle except they keep the sun's radiation in.
Do the glass tubes break very easily?
According to South African Bureau of Standards (SABS) testing, the vacuum tubes resist hail up to 35mm in diameter. This is the largest hailstone that the SABS tests with! They might break as often as the windows in your home i.e. not very often! Should a vacuum tube break, the system continues to operate without interruption. An optional polycarbonate cover can be installed in heavy hail regions or where baboons are in the area. Replacement of a vacuum tube costs roughly R 220.00.
What is a 3-port geyser?
Most geysers currently manufactured by ordinary geyser manufacturers have three ports. One port is taken up by the temperature/pressure (T/P) safety valve and cannot be used thereafter. Solar water heating systems require the geyser to have one additional water outlet to allow them to be easily coupled together. This makes a 4-port geyser. The Cobra geyser solves the problem by way of a Banjo type t/p safety valve which also acts as an outlet.
Can the solar geysers handle urban water pressure?
