Oh...another thing I forgot to mention... Using an existing geyser with a solar geyser (as the example) also gives you another big plus point! By installing "by pass" valves/taps, you can isolate either the existing geyser or the solar geyser...IE if one packs up/starts leaking/bursts...you can isolate that geyser from the system using simple taps. This will enable your home to still have a hot water supply (either solar or Eskom) while you attend to the issue! As you know....geysers always fail at the worst times (middle of night or while on holiday!) so this will give you the ability for you or someone else to temporarily bypass the problem and fix later at your convenience. May save you R1000's in an after hours call out fee!Bundy wrote: No real full proof way to get off the grid completely (without massive cost), so I prefer to reduce the cost as much as possible using a technique that was suggested by an engineer (and proven) I did work for a few years back. He uses the solar geyser as a "pre heater" to his existing geyser located inside the ceiling. The existing geyser (in the ceiling) was put on a Geyser control system, which controls the temperature. It only switches on when the water inside gets to 40 degrees. He took the cold water supply away from the existing geyser and fed that up to the roof where he installed a std 150L geyser "indirect" system with two vaccume tube panel collectors. He then took the hot water outlet on the solar geyser (which would normally go to your taps) and fed that directly into his old geyser's cold water inlet. In effect, what happens is that the solar system on his roof feeds "pre heated" (solar and free) water into his existing geyser everytime he opens a hot water tap. Thus the existing geyser never really has to "turn on" the power unless there has been excessive overcast for a day or two. On a hot day he therefore has 300L capacity... even though he has only purchased one 150L geyser.
This type of installation works very well and you do not even have to have a "geyserwise" management system if you don't want one. Simply switch off the geyser at the DB and if you have a day or two of overcast then you can just manually operate the electricity supply by switching it on for a hour or two just to heat the 150L existing geyser. The advantage of this is that when the day is warm/sunny you will use no power...but should the need arise it is easy to quckly heat up the 150L with Eskom power. In Pta this will be maybe once a month or so? Great way to almost remove your heating cost. You must make sure though that the existing geyser is fitted with a geyser blanket and that all pipes leading to and from roof are well insulated to reduce any heat loss during water transfer between the two!!!
That's the advantage of solar...in this specific example....
) which gives warning of any maintenance requirements.
