NEEPS

windyman

We've got a typical rural Aberdeenshire house (granite cottage at one end, new built block at the other end) - with heating from electric storage radiators running off-peak.

What we would like to do is generate enough hot water from solar panels to cover general use for 2 people, so we don't need a big system, and with concrete floors and granite walls in place we don't want to retro fit a wet heating system (we have separate plans to improve the insulation and burn wood to reduce our heating requirements).

So, we're asking if anyone has any recommendations for manufacturers, models, suppliers, installers etc who have done a good job?

We're willing to listen to any suggestions.

"WindyMan"

Ratchet · Mini-Neepster Joined: 23 Jul 2007 Posts: 42

Hi,

We have just taken delivery of 2 solar panels and in-roof (slate) fixing kit from ewf (earth, wind & fire), for little over £1100 inc del & vat. They are on eBay and the net. We're fitting them ourselves can't be bothered with the grants, for us they are not worth the hassle. The badly translated instructions initially provided were a scary laugh but all was well and obivous when we received the suppliers own very understandable instructions with photo's and we laid the pieces out on the ground. We haven't installed them yet nor have we bought the rest of the kit, as we are a the start of a complete renovation, so can't comment on efficiency etc. We went for flat plate collectors as they are cheaper and supposedly more robust/reliable than evacuated tubes. Any loss in efficiency by chosing flat plate, as opposed to tubes, can be overcome by installing more of them (if you have the space that is). A bonus for us is that we should avoid having to buy more slates to replace the breakages from re-roofing. The panels seem to be well made and there's not much to go wrong, so here's hoping, as by the time we get round to using them they'll be out of any garantee. We've got 2 more single panels on order, so that'll be four 2m x 1m on a 3/4/5 bed (6 persons) traditional Aberdeenshire Farmhouse that when finnished will be well insulated. We're doing things a**e aboot t*t by getting the panels first and then working out the specifications fo everything else so don't do it this way. There are people out there that can work out how much hot water you need/can expect etc and who can match the size of your panels/needs/cylinder size etc. I'll mention CAT yet again who do a couple of books on solar water heating that are supposedly good. I've just ordered them so I'll let you know in due course.

Good luck

Ratchete
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IainC · Posted: Mon Jun 15, 2009 11:31 pm Post subject:

I thought the evacuated tubes for hot water heating were far cheaper than the flat solar panels were?

Ratchet · Mini-Neepster Joined: 23 Jul 2007 Posts: 42

Hi again,

Just had a quick thought: I ken you say that you don't want a wet heating system, presumably because of the disruption caused by installing it, but have you considered skirting board radiators? We're putting them upstairs instead of normal radiators or wet ufh. Disruption isn't a concern of ours as we're not living in the house as it's bieng done up, but apparently these skirting radiators are good for retro fit situations as disruption is minimal. Thermaskirt is one of them, best to google them for more info.

Yours

Ratchet
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Lang may yer lumb reek!

Martin · Neepster Joined: 16 Sep 2007 Posts: 642

You can obtain very good tubed panels from Navitron for circa £450 for a 20 tube panel, 30 tubes £670 (complete kits from a whisker under £900). They also give free comprehensive instructions, and there's a very good forum for further help and advice, AND a very good after-sales service.
In midsummer there is little to choose in performance, but the tubed systems beat the pants off flatties early and late in the season, effectively extending the season by some weeks.
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JamesB · Posted: Tue Jun 16, 2009 8:34 pm Post subject:

we have a 4.4m2 flat collector one from AES at Findhorn. Its works very well and is very simple. I also didn't get a grant since too much hassle and did quite a bit ourselves. I can also recommend SolarScotia in Maud though, the bloke their (Stuart I think) helped us out with the final commissioning. Might be worth getting a quote from him.

the evac tubes will generally be more expensive and there is more to go wrong.

James
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JamesB
Mintlaw area

Ratchet · Mini-Neepster Joined: 23 Jul 2007 Posts: 42

Dear All,

This is what I was quoted from EWF.

2 x Solar Panels (1m x 2m each) T2 or T3 both @ £320 each

1 x In-roof kit double panel for slate @ £260

Delivery £90

Plus VAT @ 15%

I also approached AES but they said they had stopped doing in-roof installations. I would have like to go with them as they are 'local' manufacturer (the only one in Scotland - I think). There's a bloke (very friendly & informative) at Sonehaven, but he quoted me round about £700 per panel, his panels are imported (Europe - I think).

Navitron have had mixed press, they have been accused of using cheap (inference - lower quality) tubes fron China; that could just be sour grapes from more expensive European manufacturers. Generally flats are regarded as being more aesthetically acceptable; but I think that's quite subjective.

Tubes work better in cloudy conditions and early/late season when the sun is low in the sky but I did find them nore expensive/they don't come with in roof kits (you'd have to construct your own) and they alledgedly don't last as long (think blown double glazing units). On the plus side if a tube breaks then it can be individually replaced (providing they're still available or a standard size).

We're going to end up with 8msq of panels, probably over-kill in summer and we may all have to take showers every day to use up/dump the heat!! We have plans to connect our cold fill washing machine to a thermostatic mixer valve (same as for safe water temp in baths) to use up some more hot water if it comes to it. Thinking about it we may have too much heat in winter as well, what with 2 back boiler wood burners and very good insulation........mmmmm......... must do the calculations, there's not much point in over doing it.

Yours

Ratchet
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Lang may yer lumb reek!

Martin · Neepster Joined: 16 Sep 2007 Posts: 642

I'll stick up for Navitron - (they're friends of mine) - they are probably now the largest suppliers of solar hot water products in the country, and have a close relationship with the manufacturers of their products, in the UK, Germany and China, and have sufficient "clout" to insist upon, and get, quality at a cracking good price.
Nearly all of the "tubed" systems sold worldwide emanate from China - they are in fact a chinese invention, developed in one of their universities during the 70's, and there is a terrific difference in quality between products which may appear very similar (Fleabay is flooded with "el cheapo" copies). I know that Navitron now brand all their panels, and individual tubes too, so there is no mistake you're getting a pukka product.
Many of the "big name European" companies also source their tubed systems from China, but try to pass them off as European.
As for tubed systems v. flat plates, there is no doubt that performance-wise, good tubed systems are far more effective early and late in the season, yet for some odd reason, flatties tend to cost more.
Aesthetics? - that's obviously subjective - certainly some planners liken flatties to "velux" windows, and "prefer them" (can't see it myself).
Then we have the question of fragility/longevity of tubed systems - there is to be frank, a lot of guff talked - the only times we have encountered broken tubes have been when the mounting clips have been overtightened during installation, and one case where some bricks detached themselves from a chimney during a gale, and demolished a couple of tubes.
They're made from borosilicate glass (pyrex), and are incredibly tough
(someone I know wondered how tough, and clamped a tube securely, then bounced a full-weight football off it innumerable times, and was unable to break it).
Should you be sufficiently unfortunate to have a breakage, the system will carry on working regardless, just at slightly reduced efficiency (the heat is transmitted to the circulating water in the headers by sealed heat tubes, so there is no "leakage"). I would add that a new tube will cost circa £25, whereas if you get a brick on your flattie that breaks the selectively-coated covering*, that's a whole new panel that'll be needed..........
So, would I deal with Navitron? - most certainly, have done for some years, and know and trust them
Would I choose flatties or tubes? - tubes every time!

*selective coating is a coating placed on glass that acts as a sort of "one way valve" - one side appears black, the other silver, so that the sun's rays can get in, but the heat stays in thanks to the inside "mirror finish"
On flat plates, there is usually a glass panel covering a "box", each tube in a tubed system has the coatings "built in" to each tube - there are still some flat plates that are essentially just a metal radiator, -tough as old boots, but more than somewhat inefficient!
Hope that helps demystify it a bit.........
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Ratchet · Mini-Neepster Joined: 23 Jul 2007 Posts: 42

Hi there again

I haven't received my books yet but will post again when I do. In the meantime here's a couple of paragraphs from one of CAT's free info sheets which can also be found via the link below; it's worth looking at. I think their advice is more likely to be independent and trustworthy than anthing I or any manufacturer might claim.

"There are two main types of commercial solar water heating panel available - flat plate and evacuated tubes. Although evacuated tubes are more efficient they are also more expensive and if you spend too much installing a system you may not necessarily get your money back within its lifetime. (Though it would still have environmental benefits). You can compensate for the lower efficiency of flat plate collectors by installing a larger surface area. Evacuated Tube collectors

The cost of a commercial flat plate system, including installation, for an 'average' house ranges from about �2,000 to �4,000. Evacuated tube systems usually cost from �3,500 to �5,500. If the cost seems high check what it includes - for example, scaffolding can be expensive if your roof is hard to access (putting systems in to new buildings, or on new roofs obviously saves costs).

To work out if a solar water heating system is worth installing from a financial point of view, you need a rough idea of how much you spend on hot water throughout the year, and when you use it. You can then work out how long it would take to get back your investment in solar panels. As electric heating is more expensive than gas, a solar water heating system will recover its costs more quickly if you have electric water heating."

http://www.cat.org.uk/information...db&eqSKUdatarq=20020210164613

Yours

Ratchet

Sassinak · Posted: Wed Jul 01, 2009 4:14 pm Post subject:

Phil had solar panels on the roof of his Aberdeen house.
They were installed when solar first came out really 1980-81. They were still working fine when we sold the house in 2004 and had needed very little by way of maintenance apart from annual check and top up of antifreeze. The water in summer was too hot to put your hand under. Obviously they were flat tube.
The man from planning came and knocked on the door a few weeks after they had first gone up and demanded to know why Phil had installed velux windows without asking permission.
"I haven't got any Velux windows"
"yes you have I've seen them"
"No I haven't any Velux windows"
"What's on the roof then?"
"Solar panels and I've checked and didn't need permission"
"Ooh I've never deen any can I come look" LOL
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