Is it possible to get or make a hot water cylinder that is not made from metal? Around here they are usually copper. And thieves steal anything that's made of copper, and they have just done so, together with all the piping and taps. The water is heated using a solar panel, so there is no electric element or naked flames anywhere around the tank. The water can reach boiling point. I was thinking of some kind of plastic tank around 100 litres, in a box packed with fibreglass insulation.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Matty F saying something like:
I'm no plastics expert, but have looked into this briefly regarding using a large plastic tank for bulk hot water storage. From what I could see, most easily/cheaply available plastics aren't much good above
80degC and it could be quite catastrophic if it lets go of a hundred or a thousand litres of hot water. I was looking at HDPE primarily.
Your best bet might be to go for a stainless steel tank - it's worth less than copper, but you'd pay for the making of it.
On Thu, 9 Oct 2008 02:41:16 -0700 (PDT) someone who may be Matty F wrote this:-
Consolar make thermal stores out of plastic , though if thieves realised how much they cost they might steal them too. The cost is partly to do with the design to maximise stratification.
A DIY hot water cylinder might be possible, but I would place it where it cannot damage anyone if it fails. I assume you were considering direct heating of the contents. Despite the claims of some, indirect heating is best done with a coil designed for solar (a long finned coil) rather than any old length of pipe.
100l is not a great amount of water for solar heating.
Where was the old cylinder/pipes/taps? Presumably in some outbuilding.
You may be able to get a used galv steel tank. Add a big label saying galvanised steel tank, 1963 and even if they can steal it they wont. With a nice new shiny tank, once they've reached it they might take it anyway, ss is worth something after all.
This is getting a "big" problem on building sites. One job I advised, a renovation, I specced two combis with jigs avoiding cylinders. All hidden pipe to be plastic with brass compression joints. No pipes were shown. The pipes are just connected up to the combi jig and the combis safely locked up.
The two combis did a bathroom each and one combi one floor's CH and the other the other. The DHW outlets combine to fill the bath quickly. When the system was installed the combis were in safe storage. Two wireless room stat programmers were used and these removed (a simple 2 minute job) until the day of hand-over. The combis were fitted to commission and then taken away (a half days job), only being re-fitted on the day of hand-over.
I know of one job where the rads, cylinder and boiler were nicked. The cylinder is what attracts them though. If they know there is none there and pipes are plastic they will leave alone.
The two combis were cheaper than a system boiler, large cylinder, zone valves and control gear. It was far quicker to fit as well.
Unfortunately that will not help you with a solar installation. Also, even if you use the Consolar plastic cylinders (I think they have a range of them, so check) , you have to let the thieves know that the cylinder is not copper. They will not know that. Maybe a large sign on the cylinder saying something like "Caution this is a plastic cylinder". Also, plastic pipes are solar installations are not a good thing as they weaken dramatically when over 100C.
Galvanized, but then the pipework should be galvanized or plastic.
Stainless steel, as in many unvented cylinders, less scrap value I think but I haven't flogged any stainless so don't know. Many direct gas fired water heaters and some unvented ones are 'glass-lined', i.e., internally enamelled, with a sacrificial anode or electronic corrosion prevention device.
Water softener pressure vessels are made of spiral wrapped GRP tape (I think) but they mostly handle cold water. You can get softeners that will soften hot water but I'm not sure what the tanks' material. I also see a lot of commercial HWS storage cylinders abandoned in plant rooms where the system has been changed over to an instantaneous plate heat exchanger with a small storage vessel.
The thieves may cause most damage in smashing their way in and smashing off pipes and insulation before they find it to be of little scrap value. They are invariably intellectually challenged.
unless its pressurised, at 10 PSI water boils at 115C at 40psi its 141C not sure you could run a solar system in the UK at these temperature or pressures though
Well it would do, if you didn't have a Thermal Twin! Heatpipe systems can and _will_ destroy plastic pipes of all commonplace "plastic" materials short of the Aeroquip catalogue.
On Thu, 9 Oct 2008 17:54:21 +0100 someone who may be "Mary Fisher" wrote this:-
Water only boils at 100C under atmospheric pressure. Water can be liquid, rather than steam at over 100C, if it is pressurised sufficiently. The word water doesn't really convey the energy contained in this stuff, it is best to think of it as liquid steam. Systems of this type are in common use in industry and large scale heating systems.
A solar system can approach these sorts of conditions when it stagnates, though unless something is seriously wrong the water is likely to turn to steam at a relatively early stage. However, there is still a danger, though it is small due to the low volume of pressurised water.
Incidentally the term for the temperature ranges in "ordinary" heating systems is low temperature hot water. The term is as dangerous for the uninitiated as the term low voltage in electrical engineering. Low temperature hot water and low voltage electricity are both dangerous.
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