I made a box!

[Zech]

This is the third stage of my solar panels project, after stage 1, planning and design, and stage 2, plumbing.

panel nearly finished.jpg (30.15 KiB) Viewed 19554 times

One black-painted radiator in an insulated box with (almost-fitting) glass on top. This is currently plumbed (with only minor leaks) into my heating system, warming up water in the thermal store. The water that comes out of the hot tap is noticeably less cold than that coming out of the cold tap

The next stage is to add an automatic controller so we don't have to keep turning it on and off, though in this weather, having it running constantly seems about right.

[Green Aura]

Looks great - is it going to stay flat or will you angle it to the sun?

Our thermal store has points for solar PV. The plan is to build a greenhouse across the full length of the house (SW facing) with the panels built into parts of the roof. But, even building it ourselves, it's going to be a major expense so it'll have to wait a while and, in the meantime, we have no hot water unless we light the boiler.

Still it's much better than what we had before - a wheezy old boiler that spewed coal dust all over the kitchen. And a cylinder that was barely big enough to run a bath!

The weather's stifling just now so this morning I had a "cold" shower (we haven't lit the boiler since last Sunday) and it was still warmer than the cold tap water - thermal stores are fantastic, aren't they!

[boboff]

Looks ace.

I got round to painting the radiator once, now it lies abandoned in the grass, as a slow worm sun trap!

[Zech]

The radiator got painted some time ago - it's taken me ages to get round to the rest of the project. Once I'd done the plumbing, I connected up the radiator and laid the glass over the top of it. Even that was worth using in this weather, so we've been running it like that for a while.

The panels already more angled than it looks in the photo because it's sitting on a slope but yes, I am going to prop it up to a better angle. Working out what that angle should be will be an interesting exercise as we're shaded from the west, so no direct sunlight from about 4pm. I've noticed that when the sun's low, so the light has a lot of atmosphere to get through, and it's hitting the panel at a shallow angle as well, it doesn't heat up much at all. This makes me think it would be worth having the panel quite close to vertical, but then whether to point east or south becomes more of an issue. Of course, I'm not the first to face this problem, so the sensible thing would be just to look up what other people have done. I think my dad's suggestion of a rotating mount to track the sun may be a bit beyond me!

Maggie, I'm curious as to why you'd choose PV rather than solar thermal for heating water?

[Green Aura]

There were several reasons for our choice, Rachel. We wanted PV anyway, to cut down our energy bills and to provide some back-up in power cuts etc., so it made sense (to us) to extend that to the TS. Practically, the pipework will have to run straight through our living room so we didn't want hot pipes in summer, plus it's not pretty - even boxed in (you'd have to see our house to understand). Our plan is to build this greenhouse and pv panels will fit in with it much better - plus the solar gain in the house from the greenhouse+hot water pipes....you get the drill. But mainly the distance from the sunny side of the house, to the store! We figured that, even insulated, we'd not get much benefit from it where we actually wanted it - in the TS.

However, we're looking at installing another, small hot water cylinder (our old one actually ) at the other end of the house (shop area) which could very well take passive solar as well as the immersion heater. And we just happen to have a decent size radiator, for the job, plus there's a small lean-to outside the shop door which has a suitably angled pitch roof to put it on. We've talked about it in the past, but at the time didn't have the tank or radiator, so it got forgotten in favour of in-line water heaters. Your lovely box has reminded me, thanks.

[Zech]

That makes sense. Electric wires are not going to leak electricity in the same way pipes leak heat - I hope! My original plan had the panels at the opposite end of the house from the TS, but luckily my neighbour suggested putting them up on the bank, which is a much better location. Now, the pipes just have to cross the conservatory. If I paint them black and insulate them, they might even pick up some more heat on the way.

Glad to have reminded you of your radiator-on-a-roof plan