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Q: So how does it work?
A: A solar heating system uses a hot water storage tank and solar heat collector panels. The hot water moves between the collectors and the tank while the sun is shining, and is stored at the end of the day in an insulated storage tank. The system has an electrical heating element, controlled by a thermostat, for bad weather conditions.
Q: What type of temperature can I expect on a hot day?
A: Over 50 degrees. By the way, to give you an indication of what 50 degrees means – the hottest bath a man can tolerate generally is 41 degrees and a woman, 43 degrees.
Q: Will my system be damaged if I go away for 3 weeks in mid summer?
A: No, it won’t be damaged. Solar Beam systems are designed not to generate excessive, stagnant heat, so your system will not exceed 65 – 70 degrees, stagnating in mid-summer. We are very aware of the hazards of high temperature delivered water. Whilst this is possible using solar water heaters, it is definitely not the goal of a good solar system to get excessively hot. Now this might sound contradictory, but remember, along with possible safety hazards, it is a plain and simple fact that the higher the temperature, the more the losses and the less efficient the system!
Q: Will I have hot water at night?
A: The system is designed to supply hot water 24 hours a day, and that is why it is so important that the solar system is well insulated and is sized correctly for the hot water requirements of the whole family. (See question below). Hot water collected during the day is stored in the storage tank, which is very well insulated and designed to keep the water hot overnight.
Q: What size system will a family need?
A: The standard size solar water heating system needed for an average household, whether you are a large or small user of hot water, is 300 litres and for a really large home, two 300 litre systems. Choosing the correct size system is essential if you want to see large savings on your monthly electricity account. Any system smaller than this defeats the object of the exercise, as the electrical element will then be required to make up the extra hot water volume needed. Any hot water that is not used is carried over to the next day.
Q: Why is my solar system so much bigger than my existing geyser?
A: The heating element in the electric geyser can heat the contents of that geyser in a short period of time. It is therefore not necessary to have a normal geyser with a large volume. In a solar geyser, the sun has 6 hours on average to heat ALL the water your family is going to use in 24 hours. This is why the volume of the solar geyser must be much bigger than that of a normal geyser.
Q: Why do you use flat plate collectors and not the ‘new’ evacuated (glass) tube technology?
A: Quite simply because flat plate collectors are better for our application in South Africa. The history of glass tubes is that they were invented and developed by the Swiss for Swiss conditions – a far cry from our South African climate! Glass tubes have advantages ONLY when temperature above 70 degrees is required. As can be seen by a previous question and answer, high temperature in a domestic situation is not ‘clever’ at all, in fact it is downright dangerous!
Q: OK……….a dumb question! What happens on a cloudy day? Will we get any solar contribution at all?
A: Not a dumb question at all. On a cloudy day, there will still be solar radiation. To give you an example – if your car has been parked with the windows done up on a cloudy day, feel the dashboard. You will see that it is warm and sometimes even hot. This is an indication, albeit a bit of a ‘primitive’ one, of what you can expect from your water. Therefore the element will not have to work too hard on a cloudy day.
Q: Will I still be able to use my existing geyser? Is this now redundant?
A: Definitely not! We can pre-feed your existing geyser with the hot water from the solar system – (obviously it must be a pressure type geyser). We would then leave the element and thermostat on your existing geyser and disconnect them on the solar geyser. Because the geyser is being fed with the solar heated water, the element will hardly ever be used, and this is when you will see your large savings. You will now have added hot water storage for the times when you have guests, or if you would like to soak in a slightly deeper bath. However, this does not mean that you can now buy a smaller solar water heating system. It must still be sized as described above. When your geyser packs up, all you have to do is reconnect the element and thermostat on the solar geyser.
Q: Is my existing geyser insulated well enough to be included in this system?
A: In terms of the SABS 151, a standard geyser is 25% less efficient on insulation than a solar geyser. This is not necessarily a problem. The insulation of your existing geyser can be very cost effectively improved with the installation of a geyser blanket.
Q: Well, if this is the case, why can’t I use my existing geyser instead of a solar geyser?
A: Definitely not! It cannot be used for the following reasons:-
Besides the insulation factor just discussed, the basic design of your normal geyser is not conducive to connection to a solar collector.
The element in a normal geyser is in the wrong position, i.e. bottom of the tank. This means that every day you start with a tank full of electrically heated water………..so what job has the sun got to do???
The volume is too small as previously discussed.
There is also the factor that if you are in a frost area, you would not be able to run your system indirectly, i.e. closed loop. (See below)
We know there are people who advocate that geysers should be connected directly to solar panels. BEWARE!!! This is opportunistic and poor practice, and nothing more than a means of getting a sale. I have been in the industry for over 37 years, and if this was a durable, long term, cost effective solution, then I certainly would have advocated it.
Q. Can my solar system be damaged by hail or frost? What happens in winter?
A: Solar Beam systems are designed specifically for South African weather. So the short answer is no! Armour-plated glass is used on the panels, so hail is not a problem. In frost areas, and we consider a frost area to be anything below 3 degrees, we would use an indirect system (closed loop). This means that the solar collectors are filled with a non-toxic, anti-freeze liquid. This liquid is heated by the sun, and this heat is then transferred into the water of your solar storage via a patented Solar Beam heat exchanger. This means that your solar collectors will never have plain water in them, and thus will never freeze.
Q: What do I need in place to get up and running?
A: A roof that has a North facing pitch or a roof where a stand can be mounted.
Q: What about maintenance?
A: Maintenance is negligible, and merely entails hosing down the panels (flat plate collectors) occasionally to remove excess dust (DO NOT hose down the panels in the heat of the day – this is very important!). The system will work uninterrupted for years.
Q: What is the guarantee period?
A: The Solar Beam system carries a 5 year warranty on the collectors and storage tank. There is Solar Beam equipment that has been in use for well over 30 years.
Q: There are so many products on the market, I am confused. They all sound so plausible. Who do I believe?
A: OK….here are a few pointers to take into consideration when making this all important decision.
Ensure that the product you choose has a valid SABS Mark of Approval. This is essential to comply with the latest building regulations. Test reports do not constitute an SABS Mark. We have it on good authority from leading financial institutions, that they will not provide insurance cover for non SABS products, so insist on seeing a copy of the supplier’s SABS Certificate on their product, to prove that the system has a standard to which its performance can be measured. Do not be confused because a product has been endorsed by a particular organisation. This does not make it legal. SABS is the only yardstick to measure all products that are installed in houses today, in compliance with the National Building Regulations.
Do not be confused by salesmen telling you that their products have a European mark of quality which far exceeds SABS. This mark is fine for Europe, but we have extremely harsh weather conditions in South Africa, and these have been taken into consideration in the SABS testing.
Check the track record of the company. How long have they been in the solar business? Remember, many companies have been in business for a long time, but have only recently embraced solar water heating, and their experience is limited. Look at the track record of the company. Ask for more than one reference, preferably a client who has had a system for over 5 years. Remember, if the company does large industrial systems as well as household units, your home shouldn’t be any challenge to them at all.
Make sure that the company you choose has been in business long enough to carry the guarantee they offer. There has been an explosion of solar water heating suppliers. Be wary of extended guarantees. These are generally offered by these new companies, attempting to gain an advantage.