[Closed] Tell me about your solar thermal installations.

Navitron kit is pretty good, have fitted a few systems. £5k really is steep!! Where in the country are you?
I should should have put the curtained design design production years ago when I realised it would be a solution to stagnation!

I put my experiences in a long thread here

http://singletrackmag.com/forum/topic/solar-water-thermal-panels-the-installation-w-pics

It's been an excellent system, with few issues.
I fitted some salvaged radiators underneath the collectors a few years ago so that the fluid can be valved through them as a heat dump /bypass when we go on holiday.

You were right a couple of years ago I'm afraid ...... PV is still where it's at as solar thermal is very much a one trick pony while electricity can be used for lots of stuff.

If you have an immersion in the tank then I'd still go PV with an Immersun type device.
Immersun themselves went bang last year but I think someone else may have revived the brand - I bought a reconditioned v2 a few months ago after my Solar Immersion went wrong. Plenty of other manufacturers though.

Seems you've already found the Navitron forum - tons of info available there.

Get PV, you won't regret it.

Edit: You'll have no issues with PV, no worries about it overheating/freezing/leaking and no pump required to keep the liquid moving 24x7.

Soz, but it's just better 😉

Cannyj, I live in Chippenham near Bath. I worry about the mechanical reliability of the curtain.

Hmmm, what you really need are solar tubes with an electrochromic layer so you can electrically control the opacity. No moving parts.

4 panels on the roof feeding into a Tisun 1000L thermal store via a variable input heat exchanger - in winter it heats the bottom of the store which feeds the underfloor heating, in summer it heats the top which provides hot water. We have a drying room with underfloor set at 22C which dries everything without needing the tumble dryer, and our hot water never runs out. This despite 2 teenage sons who have endless sports kit to wash and take long showers. As we're not on mains gas oil was a big expense, this has now reduced dramatically - so we're very happy we did solar thermal!

Shame Hoodoo, I'm In Nottingham electrochromic would be interesting. Lo tech always good fixable option IMO sometimes.

Water is cheap to heat, using oil 200L of water from 7c (winter temp) to 50c would cost about £0.50, less in the summer.

1Kw of power from oil costs about £0.05 as opposed to electricity which costs £0.16 - if you're gong to produce something from solar it makes more sense to produce electricity than hot water.

I built a system from scratch a few years back with pipes big enough to thermo-syphon so no pump or controls. You just have to put the tank above the panels. It only cost me 1100e to build and provides free hot water for 5 months of the year (SW France) then serves as a pre-heater for a conventional tank the rest of the year. It feeds the washing machine direct on the fill cycle.

Maintenance has been cleaning the panel (several times a year) and topping up fluid once a year. It'll pay for itself soon after eight years, it's hard to say exactly when as I don't know exactly how much it's contributing to energy savings we've made on several fronts.

I also fitted PV. It's already paid for itself and started to make a profit at 7.5 years.

At £5000 I'm not sure you'll ever save money with it. Get a cheaper quote or go with PV instead.

I have both pv, and thermal fitted. If you have limited roof space go for a thermal system, they work very well for around 6 months of the year, and on a good day will heat a 250l tank to 90 degrees by around 2pm. if you have lots of roof space go for pv first. If i were you i would buy a system from kotly (cheap), get a roofer to fit the roof mounts, plumber to attach piping, electrician, to attach electrics. You will struggle to spend 2.5k doing it this way.

Feeding the pv into a tank is all good at the mo, but when home batteries, and electric cars become the norm, there will be no spare pv capacity to heat a tank, so in the future, thermal will become a better altrernative.

thermal will become a better altrernative.

Are you presuming that there's space for both PV and thermal?
Given a thermal installation cost of, say, £2000 you could heat your 250L tank using oil every day for 9 years for the same money (gas would be longer still). This assumes a perma-summer with long sunny days, but the reality is that 6 months of the year it's not like that in the UK so the breakeven point actually increases to about 18 years.
If you only have space for one set of panels then thermal just doesn't make economic sense - [url= http://www.navitron.org.uk/forum/index.php/topic,25212.0.html ]but don't take my word for it[/url].
Although I have space for thermal as well as the PV I still can't bring myself to get it installed - I would def add a load more PV if I was allowed though.

I built my own system for £700, which included the cost of an unused 160 litre cylinder off Ebay. I got the 20 evacuated tubes from this chap near Bolton: http://www.solarproject.co.uk/

The system is very simple; I set the cylinder up in the attic resting on the studwork for the airing cupboard below, which also contains a twin-coil 160 litre cylinder. The attic cylinder is plumbed in tandem with the main house cylinder, so that water flows from the header tank, through the attic cylinder where it is pre-heated by the panel and thence down to the house cylinder where the combi boiler finishes the job. The transfer fluid is water with 25% car antifreeze and it's an open system with a small plastic header tank up it the apex of the roof. I set up the pipework so that it all slopes uphill so the system self-bleeds quickly. The pump is a small plastic job running off a 12v DC cellphone charger; it's amazingly vigorous for its size and you can just about hear it humming when it kicks in. The differential controller is also in the attic and there's a remote control panel down in the utility room, all the wiring is simple 12v stuff for which I used alarm cable. In eight or nine years it's never lost water and only broken down once when the pump motor got a bit tired and seized, blowing a fuse, so I've now fitted an inline 2a fuse in the supply to the pump. Peter at Solar Project is happy to chat, give advice and demonstrate the system to callers.

Fitting the panel to the roof was easy, just an SS frame held on by four SS straps that go up under the tiles and are attached to roof timbers. I used 10mm copper pipe, which I insulated with AC insulation. Later on I added a 12v diverter valve, which is supposed to open once the attic cylinder hits 60c and send excess heat downstairs straight into the second coil in the house cylinder, it works if you dip the attic cylinder sensor in a cup of boiling water but I've never been at home on the few occasions in June or July when we've hit 60c.

I reckon it's just about paid for itself by now, I've never calculated seriously but reckon it's saving us about £60-£70 a year in gas as it gives us all our daily shower water in summer. We are in Lancashire and the panel faces slightly south of west. Even now when the sun shines the controller is detecting usable heat in the panel manifold and the pump is kicking in occasionally.

I've got some pictures on Photobucket but can't link you to that now as I'm at work and that site is blocked. Can send you the link later if you're interested.

You are correct Sharkbait. However after 9 years, it becomes free, oil is going to go up in price, area of roof wise it is better for heating water, and most importantly you get that warm smug feeling of heating water for nothing (once installed). I cant stress how nice the feeling green energies give you.

However after [s]9[/s] 18 years, it becomes free, oil is going to go up in price

Actually the price of oil dropped last year 😉 - electricity on the other hand is always going up.
That was a pure comparison of heating water with oil and ST. If you had PV instead of ST you'd be getting free electricity after 6-7 years (our £10k installation will have paid for itself next year - and it's a lot cheaper to install now).
PV only needs daylight to work so it can still produce in the winter, but ST needs the heat from the sun.
For a given roof area PV outperforms ST.

For a given roof area PV outperforms ST

. Perhaps true in December, most definitely not the case in June. There's plenty of information about the relative efficiencies; solar thermal beats PV in terms of power/m2.

Sharkbait, read what i wrote, "if you have the room, install pv first". If you only have room for 2 panels, install thermals. I am generally agreeing with what you are saying.

most definitely not the case in June.

Maybe only in terms of heating water, but PV is still plenty efficient enough for heating domestic hot water.
The below image shows the water heating of our smaller 3Kw PV system at our [completely electric house] in N Wales... much further north than yourself. As you can see it happily heats a 250L tank from 26c to 64c in 6 hours and would have continued to heat it but the immersion thermostat cuts out at 64c. I'm not really sure how much more hot water you need in the summer!
[img] [/img]

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We're a family of 5, including 3 teenage girls, and from early May to the end of September we almost never have to boost the hot water heating - the PV deals with all of it plus it runs kettles, cookers, heaters, charges batteries, etc. which is obviously out of the scope of ST.
PV is just more useful.

... and this is what's been happening over the last 8 days, the house is unnoccupied at the moment.
Once the immersion thermostat trips (which I'm surprised it hasn't yet) the Immersun will send power to a simple convector heater.
[img] [/img]

But you probably have over 12 PV panels to do that and 2/3 thermal panels would do the same. I terms of cost per KwH of water heating without subsidies or referential feed-in tarifs solar is more efficient. Both is ideal, but I agree with LeeBaxter, if you have limited space then go solar thermal. If you have lots of space and only do one then go PV first. If you want the best bang for you buck then do both with thermal for heating/pre-heating water.

Edit;: and you really should have a heat pump hot water tank if you heat a lot of water with electricity. 😉

and you really should have a heat pump hot water tank if you heat a lot of water with electricity.

interesting ... could you explain?

[img] [/img]

[url= https://www.superachat.fr/ariston-chauffe-eau-thermodynamique-nuos-evo-110l-3603545-8593 ]Ariston[/url]

Interesting - never seen one of those before.

Have a Solartwin flat plate collecter at home - feeds straight into and out of the existing HW cylinder, flexible pipes that expand when frozen so no antifreeze required. 10 years old and has been really good. At the time PV was extortionate, and we only have a small roof - so thermal made a lot of sense - would do again now in the same circumstances. Get about 1MW of heat per year off it.

Installed the same at work 2 years ago - bigger roof area but we maxed out our PV allowance on the meters, then still had space for a thermal panel.

Just dug out this thread as I'm looking for a new boiler and did a bit of research from past experiences

Got to thinking about a thermal installation and a new tank. So just heat exchanger bits, connections, new tank and installation, rough figure, what are you looking at for this?

Damn my Apple generation plug and play mind...
I just want to chuck something on the roof to save some C02 and knock my bills down a bit!