Green Building Forum - Thermodynamic solar panels Sun, 06 Sep 2026 22:23:50 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115521#Comment_115521 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115521#Comment_115521 Thu, 25 Aug 2011 23:09:18 +0100 tullyfoyle at 55 centigrade for 6 people every day - guaranteed.
Ted]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115524#Comment_115524 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115524#Comment_115524 Fri, 26 Aug 2011 00:33:35 +0100 mike7 Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115624#Comment_115624 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115624#Comment_115624 Sat, 27 Aug 2011 18:22:50 +0100 Gavin_A
depending on the heat pump, it'll be better (better COP) than an ashp in sunlight, but probably worse at night unless there's much wind to move air across it, although it will have a bigger surface area than in most ASHP's which will compensate for this to some extent.

could be a good option for some though.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115625#Comment_115625 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115625#Comment_115625 Sat, 27 Aug 2011 18:55:59 +0100 JSHarris
It also has the advantage of not needing (potentially noisy) fans, which is one thing that has put me off using an ASHP.

The only potential problem I can see is the possible need for periodic recharging with refrigerant, although this is probably no worse than that needed for something like an air conditioning system.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115630#Comment_115630 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115630#Comment_115630 Sat, 27 Aug 2011 22:16:31 +0100 SteamyTea Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115637#Comment_115637 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115637#Comment_115637 Sun, 28 Aug 2011 10:22:42 +0100 Fred56 Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115642#Comment_115642 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115642#Comment_115642 Sun, 28 Aug 2011 12:18:52 +0100 SteveZ You might be interested in another idea I checked out a while ago. I found a couple of manufacturers of PV-T panels (Voltherm and an Italian company) where the photovoltaic panel is backed by a liquid-based cooling system, rather than the gas in the thermodynamic panel. There is a British company using these panels and their own heat pump to provide hot water (Newform Energy), although it may be still in development. You get a greater electrical output from the panel, as it operates at a lower temperature due to the cooling. You gain a large area of solar radiation collection on your roof, which, according to the literature and published results, will collect usable amounts of heat energy even at night with sub-zero temperatures. I thought at the time that the initial cost would probably be too high for me and wondered if there would be enough energy available from the roof panels to be useful (and the added complexity is to be considered too). If one gas-cooled panel can provide enough energy as claimed above, several liquid-cooled panels should not have a problem. In theory, you should get the FIT payments for the PV side and RHI for the Solar Heating and more for the Heat Pump function, although not yet definite.

http://www.newformenergy.com/hybrid-solar-solution]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115644#Comment_115644 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115644#Comment_115644 Sun, 28 Aug 2011 18:18:31 +0100 Gavin_A
I reckon these systems will work very well for use with either a small ground loop for the heat pump, plus a big buffer tank, and biomass boiler for the peak heat demands in the depths of winter, with the heat pump supplying most of the heat the rest of the time.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115646#Comment_115646 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115646#Comment_115646 Sun, 28 Aug 2011 18:57:29 +0100 JSHarris
What I will be very interested to see are the real-world performance figures, rather than the manufacturers claims.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115649#Comment_115649 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115649#Comment_115649 Sun, 28 Aug 2011 21:03:08 +0100 Gavin_A Posted By: JSHarrisI'll be very interested in seeing how this works out, although using a biomass boiler seems odd, in light of the non-sustainable nature of burning biomass for heat.
yeah, but that's only perceived wisdom according to this forum, rather than reality, so I'll not worry overly about that other than specifying high efficiency, low polluting gasifying log boilers.

anyway, let's keep at least one thread on topic eh.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115651#Comment_115651 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115651#Comment_115651 Sun, 28 Aug 2011 21:32:22 +0100 JSHarris Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115652#Comment_115652 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115652#Comment_115652 Sun, 28 Aug 2011 21:48:35 +0100 Gavin_A Posted By: JSHarrisHow many acres of woodland are needed to heat a single house, assuming that the wood is sustainably managed? Is it realistic for every home to own and manage such an area of woodland? No, is the simple answer.
you're making the same basic mistake that lots of people here seems to make.

nobody I'm aware of has ever seriously suggested trying to heat every home via biomass, and making that point on a thread where we're discussing solar/air sourced heat pumps as a source of heating is particularly odd.

UK heating is currently supplied by gas, oil, electricity direct and via heat pumps, and to a small extent coal and biomass. In future biomass will hopefully move up that list a bit, probably mostly replacing oil, and electric, and probably matched in varying degrees with solar water heating, and heat pumps, with the biomass providing top up heating.

Biomass is (or at least can be) a sustainable fuel source when used as a part of the overall mix of available lower carbon fuel sources, in situations where it is sensible to use it - ie mostly in the countryside in areas where local fuel supplies are available, and for the time being at least, where mains gas isn't.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115653#Comment_115653 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115653#Comment_115653 Sun, 28 Aug 2011 21:56:14 +0100 JSHarris
Biomass is viable only as a very small scale energy source where it is a waste product. The whole idea of wasting agricultural land by growing fuel for a tiny percentage of the population just doesn't make sense, no matter how anyone chooses to do the sums or try to justify their own view.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115657#Comment_115657 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115657#Comment_115657 Mon, 29 Aug 2011 09:08:17 +0100 owlman ]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115661#Comment_115661 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115661#Comment_115661 Mon, 29 Aug 2011 09:27:26 +0100 SteamyTea What I would like to see is an Instantaneous Power/Time chart and some data on when and power the HP is producing. Couple this with the energy demand of the HP would be interesting.
Have I mentioned burning on this thread yet :wink:]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115663#Comment_115663 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115663#Comment_115663 Mon, 29 Aug 2011 09:42:51 +0100 owlman Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115664#Comment_115664 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115664#Comment_115664 Mon, 29 Aug 2011 09:52:10 +0100 SteamyTea My gut feeling is that separating the systems will not be so bad even if it does take up more roof area, bit like driving around in an old VW Camper just for the occasional night away, a hotel and a small car would work out better (but then I hanker for an old split screen and want to depress prices, but then I saw a McGregor 26 and now want one of them instead)
http://www.macgregor26.com).]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115666#Comment_115666 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115666#Comment_115666 Mon, 29 Aug 2011 10:34:19 +0100 Phil.Chaddah-Duke
The statement "The chart above shows PowerVolt panels absorbing energy at -10°C in the dark, meaning that the system will perform at higher efficiencies than air-source heat pumps in similar sub-freezing overnight conditions.". Can someone explain this? Why will the panels provide anymore heat in the dark @ -10°C than an air source HP?

I don't like the idea of installing such a new technology, although I guess its just a combination of very established and proven technologies!]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115667#Comment_115667 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115667#Comment_115667 Mon, 29 Aug 2011 11:01:58 +0100 JSHarris
I'd have thought the same would happen to these panels whenever the outside temperature drops to a point where the panel surface ends up below freezing point. It's possible that they reverse the cycle to periodically defrost the panels, but this is even more wasteful on an open panel than it is with a fan-blown exchanger, as at least with the fan-blown unit the fan can be turned off during the defrost cycle to minimise heat loss and speed up defrosting. If they do use a periodic cycle reverse for defrost it will dramatically reduce COP I'd have thought. Given that we frequently seem to have winters where it's both cold and damp I suspect that panel icing must be a potential problem in our climate.

Having said that, if this system were used primarily during the day, to charge up a big thermal store, then it might not be necessary to run it at night when there would be a greater risk of icing up.

I'll be interested to see how they get around this potential problem, as it's the only downside that I can see in what looks to be a clever idea (other than maybe a high cost.....).]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115673#Comment_115673 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115673#Comment_115673 Mon, 29 Aug 2011 13:04:06 +0100 Gavin_A
Combining it with a heat pump will mean 55/60 deg water temps can be gained from 25 deg panels temps (or lower), meaning the PV panels can operate at or around their actual rated output in full sunlight rather than losing 15-20% of their output (due to ~0.45% per degree loss in performance of crystalline PV panels)

steamy tea - separating the systems out would mean the PV system didn't benefit from the cooling effect, so I'm not sure where you're coming from with that idea.

These systems will not be suitable for all situations, as apart from anything else, the amount of heat that can be delivered from them in summer is way in excess of a standard households hot water demand (depending on the size of the system of course). that said, if you use the uninsulated version it ought not to make much difference to the PV panel temp when not running, so it would still be beneficial for the time it's operating, just not as much so overall compared to situations with high levels of year round heat demand.

JSHarris - I agree that the benefits in minus outside air temps will be largely down to the no/minimal defrost cycle. In an ASHP the defrost cycle is needed more to prevent the air intake/exhaust actually freezing up, and the fan and other moving parts getting iced up. None of this applies the a PVT so long as it's above the glycol's freeze protection levels it'll be fine (though icing up of the heat fins will impact on the performance of the system).

The system's also not really being sold as something that's supposed to be capable of doing the houses entire heat load, more something that can do the bulk of it for much of the year, but will need a secondary heat source during the coldest periods. Hence matching with biomass, and / or a small ground loop for the heat pump (potentially with summer heat being pumped into it if ground conditions allow), or the existing oil / gas heating system.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115674#Comment_115674 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115674#Comment_115674 Mon, 29 Aug 2011 13:09:03 +0100 Gavin_A Posted By: owlmanPresumably installers would have to be MCS accredited in all three disciplines,- more upfront fees for the workers? I've only just nicely got the PV installed and about to start the ST and along comes this, and the goalposts start to move again, "C'est la vie".
yes, but then why would you want this not to be the case?

I'd not want a heatpump bod installing these without knowing anything about PV or solar thermal, similarly as a PV and solar thermal bod I'd not want to be installing the heatpump and heating side of things without being properly trained in it (although I'm sure I could sus it out).

These are ~£30k systems, so it's reasonable for a customer to expect the installer to be fully trained in all relevant disciplines.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115675#Comment_115675 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115675#Comment_115675 Mon, 29 Aug 2011 13:32:20 +0100 JSHarris
I still think it's a potentially good solution though, particularly if combined with good thermal storage. Pity about the price tag though, £30k is a heck of a lot of dosh and will put it out of reach for many, even with the current level of FITs subsidies.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115679#Comment_115679 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115679#Comment_115679 Mon, 29 Aug 2011 13:49:24 +0100 Gavin_A
It should be eligible for both FIT and RHI, and basically most of the heat generated during daylight hours will effectively be largely free of fuel costs.

I'm not entirely sure about the low temperature performance claims, it could also be they're also mainly referring to daytime situations when the outside air temp is below freezing, but the panels will be absorbing heat from the sun. I guess the other factor is the huge collector surface area - effectively around 50m2 if you include both sides of the panels.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115681#Comment_115681 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115681#Comment_115681 Mon, 29 Aug 2011 14:04:25 +0100 JSHarris Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115683#Comment_115683 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115683#Comment_115683 Mon, 29 Aug 2011 14:32:05 +0100 SteamyTea Posted By: Gavin_Asteamy tea - separating the systems out would mean the PV system didn't benefit from the cooling effect, so I'm not sure where you're coming from with that idea

Think JSH is really asking the same questions. But if the HP is not running much in the summer, then where is the advantage of cooling the panel in winter.
Don't get me wrong, I like the idea, just think it is a bit complex for little or no gain, and at that sort of money you could buy a lot of insulation.
I would have to see real operational data as well as manufacturers data before I could recommend that. Is there any real data yet?]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115687#Comment_115687 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115687#Comment_115687 Mon, 29 Aug 2011 15:06:55 +0100 tiimjp1
Maybe i'm wrong but all these stitch up regs are great for those who want to make money but not those who want to save it. I know there is a market for specialists but you don't have to use most of them if you don't want to throughout your build but some things you have no option and its mostly there to stop DIY people having fun.

Obviously the final connection to the Grid has to be correct but as long as the circuits are protected correctly against faults which after all can occur in specialist equipment, whats the difference.

What would happen if you got an MSC company to install 1Kw of solar PV and then you as a DIY man added your own home made panels to the curcuit to increase the output?

just a simple query lol]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115688#Comment_115688 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115688#Comment_115688 Mon, 29 Aug 2011 15:29:07 +0100 Gavin_A Posted By: tiimjp1It's such a shame that DIY projects cannot be taking advantage of FIT's have you all noticed how prices have skyrocketed through MSC accreditation requirements which is not good for those clever DIY people who want to save money and do things as cheap as possible.
erm actually, not really.

installed prices for 4kWp of pv have dropped from around £16-18k under clearskies to £10-12k now, 18 months later.

And the panel prices have also dropped accordingly, so anyone wanting to do it DIY has also benefitted, although they'd not be eligible for FIT's unless signed off by an MCS company.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115689#Comment_115689 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115689#Comment_115689 Mon, 29 Aug 2011 15:33:19 +0100 SteamyTea Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115690#Comment_115690 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115690#Comment_115690 Mon, 29 Aug 2011 15:34:11 +0100 JSHarris
What I would like to see is a means by which a competent amateur (as in someone not doing it as a business) can gain the required certification qualifications at a reasonable cost. I looked into this when Part P started to impact on DIY electrical work, but found that it was pretty tough for someone reasonably competent (but not in the trade) to get the required qualification. My idea was that I'd get qualified (one of my degrees is in EE anyway) then both look after my own electrical work and offer a free inspection service to any other competent DIY'er.

Similarly, I'd love to do the same for solar PV installations, and maybe wind systems too, but it seems that hurdles have been deliberately put in place to try and prevent people doing just this. There's no safety argument for this, as presumably all qualified individuals have to be deemed to work at the same level of safety awareness.]]> Thermodynamic solar panels https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115692#Comment_115692 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7740&Focus=115692#Comment_115692 Mon, 29 Aug 2011 15:46:07 +0100 Gavin_A Posted By: SteamyTea
Posted By: Gavin_Asteamy tea - separating the systems out would mean the PV system didn't benefit from the cooling effect, so I'm not sure where you're coming from with that idea


Think JSH is really asking the same questions. But if the HP is not running much in the summer, then where is the advantage of cooling the panel in winter.
Don't get me wrong, I like the idea, just think it is a bit complex for little or no gain, and at that sort of money you could buy a lot of insulation.
I would have to see real operational data as well as manufacturers data before I could recommend that. Is there any real data yet?
PV performance increases don't stop at 25 degrees, so a cooler panel in winter will still perform better than an uncooled panel (upto the point at which the cooling results in ice forming on the panel).

On days of full sun all day in summer, then I'd think the heat pump would only operate for a relatively small part of that time to supply hot water requirements for a house. However, these days are relatively rare, and the majority of the time in this country we only get a few hours of full sun, so I'd think that on average through the summer the heat pump would be operating maybe 50% of the full sunlight hours, during which time it will be improving output of the panels by 15-20%, and the heat pump efficiency will also be maximised even compared to an ASHP. For the rest of the year, the proportion of sunlight time the heat pump would be operating would increase.

Manufacturers are claiming around 20% increase in annual output from the PV panels, which I can see being possible in some circumstances (eg some of the systems seem to have either larger hot water requirements or goundloops for interseasonal heat storage. I'd expect somewhere in the 10-15% increase in annual output to be more likely for a family home.

The increases in performance of the PV is only one part of the story though, with another side being much higher COP's than ASHP, particularly for the water heating side of things, and the potential to be combined with a much smaller than usual ground loop to supply heat at night instead of/as well as the panels.

The 3rd aspect being that if combined with a decent sized thermal store, most of the heat energy can be produced when the panels are generating power, so you're not going to be paying for that energy source. Obviously you could achieve this with an air or ground sourced system combined with PV, but then you'd not be getting the additional 10-20% electrical output from the panels which alone could well supply maybe 1/3 of the heat pumps electrical requirements.]]>