Combined PV / Thermal Panels

Worcester · Nov 23, 2013

We've got a job to do where the client wants both PV and Thermal so we're looking either for a combined panel or matching ones

I know that Viridian do a matching pair, anyone had experience of either matching units or combined units and if so what is the performance and performance / cost ratio like?

Re Combined units the cost / performance ratio is important as the reduced output of either or both may mean the the Viridian (or others - hints please) matched approach may offer a better return for the £ invested. (reduce PV by a couple of panels and add in a couple of Thermal panels..)

Worcester · Nov 25, 2013

Bump!!! That's it 66 people viewed it and no-one got any other solutions? C'mon one of you (apart from GavinA) must have done something similar surely... Or there again maybe not

I reckon this will become more popular as the FiT goes down and the RHI goes up...

SpitfireW'sale · Nov 25, 2013

I doubt there are many installers that have done this. We have looked at supply of the combined units but concluded the market is unfortunately too small to invest in at the moment.

Manufacturer I looked at a while ago was New Form Energy and they looked pretty decent. I have read Romag are going to be manufacturing on behalf of a company called NTD. Not heard of NTD before but if they have impressed Romag they are probably good.

Regards matching panels - Schuco might be worth a call as they make both.

a1colly · Nov 25, 2013

Hi Worcester

We've fitted 'new form energies' product a PVT panel with a mini heat pump to boost performance but I have to say they have been disappointing in performance. They claim the pv produces better output due to the regulated temperature from the thermal defect but the real life figures after a year don't support it. They are also very fiddly to fit, one system is a push fit plumping system plumbed like a radiator system . The other panel is plumbed in series with flow gauges installed to balance the system and Is easier to install. The big issue is with the heat pump causing freezing on the pipes due to the compressor removing all of the heat from the fluid. Major headache if you can get every single mm of the pipe tightly lagged and glued.

whinmoor · Nov 25, 2013

Worcester said:
Bump!!! That's it 66 people viewed it and no-one got any other solutions? C'mon one of you (apart from GavinA) must have done something similar surely... Or there again maybe not
I reckon this will become more popular as the FiT goes down and the RHI goes up...

Sorry, not done anything like this. I remember having a discussion about a product like this with a rep from Solyndra - possibly at Ecobuild a couple of years ago. Unfortunately, they went bust...

Solyndra - Wikipedia, the free encyclopedia

whinmoor · Nov 25, 2013

Actually, reading that, I'm not sure it was a thermal system at all. Just PV using tubes.

logical · Nov 25, 2013

Hi Worcester, we offer a PVT panel from Fototherm. Have a look and if it is what you are looking for give us a call.
Logical Energy - Thermo-Photovoltaic Modules PVT

Worcester · Nov 25, 2013

Thanks all, we've got a roof space available of 13.3 m x 4.2m points just East of South, so pretty large area. The Newform Energy and Fototherm ones look interesting. - Newform's website though: No Downloads, No 'phone number, no company details, no address - it's all grand design stuff with no substance....

and a1colly, I read through the Newform site and your comments tie in with what I would have suspected. - I've seen frozen thermodynamic units (last week - should have got a photo

) and they have no defrost cycle and I guess these don't either, so just gotta accept a c**p CoP at that point or switch it off.

stanwaterman · Nov 26, 2013

Combined panels should be good eventually- keep watching. Remember PV is about 15% efficient so 85% of the incident solar energy ends up as heat. Ideally the PV cells need to have their rears washed by a cooling liquid which then goes into a heat exchanger, best of all a heat pump. The PV would work better too, being a bit cooled. The setup would be heavy for roof mounting I think but you'd collect nearly all the energy from the sun. I don't think anybody makes something this good yet, but they will! What would you do with all that heat in the summer? Heat your pool of course!

logical · Nov 26, 2013

You will find all the downloads on our site plus a telephone number!

That is a good sized roof. Room for a lot more than 4kWp. The Fototherm is based on a standard 250W Mono Bosch panel and are 50mm deep ( Newform are 100mm I believe). Would they want or are they able to exceed 4kWp?

What is the hot water demand? What type of heating does the building have? Is there room for a thermal store? (300 litre min).

In many cases it is more economic to opt for seperate PV and thermal systems. The thermal aspect of PVT will not work as efficiently as a good thermal system especially in the winter months.

PVT has it's place and in some instances it is the ideal solution. However it must be considered carefully and designed properly.

jerriais · Nov 26, 2013

I think Zen used to do a PVT panel. Belgian company but used to be quite active in the UK.

Gavin A · Nov 26, 2013

Worcester said:
Bump!!! That's it 66 people viewed it and no-one got any other solutions? C'mon one of you (apart from GavinA) must have done something similar surely...

fwiw, we've not installed PVT, though I did a lot of research into it a couple of years back, and almost went the new form energy route.. was planning to combine it with small GSHP ground loops to avoid the issues A1 colly mentions, but then the price drops in solar PV made the economics stop stacking up, specially when RHI got put back again and again.

I think the problem with the performance advantage claims for the PV side of things is that the cooling isn't uniform, and with maybe a 10 deg temp differential across the panels that'd be around a 4.5% difference in output from best to worst cells, with the entire system operating at the output of the worst performing cells, and feeding the excess power into them. I could even see that the performance difference could be enough to trigger bypass diodes depending on the layout... That's when used for hot water only, with a heat pump it'd be operating at a much lower temperature so should give some advantage, but would need a cut out and alternative heat source for when the temp drops towards the freezing point of the glycol.

the viridian solution seems to be a good reliable, well thought out solution which while not PVT, at least looks the part, and isn't a compromise between either technology.

The Solar King · Nov 26, 2013

Would definitely go the Viridian route. Known quantity, known performance.
Fitting is straight forward and they look really good.
You have plenty of room to play with.

Worcester · Nov 26, 2013

From all that I've read the performance of both is reduced. however the sum of the outputs even with the reduced performance is better than seperate systems occupying the same total area, i.e if you can get say 16 PVT panels versus 4 flat panel collectors and 12 PV panels, the 16PVT should outperform both the 4 flat AND the 12 PV

I'm maxed for a few days, so will have a look in the evenings... keep the info coming I am listening.

Need to look at the ££ side of things now to see if that works or wipes out the whole thing! and end up going for a lower output dual system with much better financials.

Heating will be underfloor and GSHP and a thermal store (all being redone at the moment here's a photo of the property (don't you just love my typical clients

) (thats 8 m to eaves, and artificial slate on a warm roof

)

@logical I dowloaded the stuff from your site, thanks, just need to know some prices - you can get my email address from the website in my siggy in the info one will work.

[ElectriciansForums.net] Combined PV / Thermal Panels

puddy · Nov 28, 2013

If only I could afford to live there

Combined PV / Thermal Panels

Worcester

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Worcester

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SpitfireW'sale

a1colly

whinmoor

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whinmoor

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logical

Worcester

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stanwaterman

logical

jerriais

Gavin A

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The Solar King

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Worcester

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puddy

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