Ferdinand

Solar Dynamic Panels for Water Heating

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I had not heard of these. The mechanism seems to be to circulate a cooling fluid, such that more heat is generated than used by the circulating pump.

 

A relatively new addition to the solar panels market, solar dynamic panels produce hot water in all weather conditions. Attached to the roof of the home, the panels do not require a backup system of gas or oil and a single solar dynamic panel can provide 55˚C hot water sufficient for a family of five every day throughout the year.

 

Has anyone used them, and are they still a thing? They seem to cost about as much as a big boiler.

 

http://thegreenhome.co.uk/heating-renewables/solar-panels/solar-dynamic-panels-overview/

https://www.thegreenage.co.uk/buy-thermodynamic-panels/

 

solar-dynamic-panels.jpg

 

Can @Onoff make one out of beer cans and an old fridge?

Edited by Ferdinand

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They are an air source heat pump without a fan.  I looked at fitting them, and even went so far as to visit a UK importer to see them working, but despite best endeavours, neither I nor the importer could obtain any independent test data as to their performance.  There are people in Ireland with them fitted who have reported that they work well, and they seem to be relatively popular in Spain and Portugal (which is where they come from), but the absence of any hard performance data put me off, as did the fact that one dubious UK importer was marketing them as a "Magic Box" and when I spoke to them at a show it was clear that the people selling them were snake oil sales people, who knew nothing about the things at all.

 

In principle they are a reasonably good idea, although they have no real icing control, and the panels will ice up badly in damp weather, and this must reduce their performance (but there's no data on this at all).

 

One thing that was clear, was that they aren't "solar" panels at all, and that the vast majority of the heat they extract comes from the air, not any solar radiation.  They were banned from being on the MCS register due to them being marketed as "solar" panels, some years ago.  They also seem to work well (some say better) when mounted vertically, which makes sense as that may then allow better convection and that in turn may help to reduce icing in damp weather.

 

Finally, they have to be installed by someone with an F gas ticket, as they are much the same as any other split ASHP, in that they need pumping out and gassing after installation.

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That sounds like a heat collector for a heat pump system?  I wish they would just say so rather than cloak and daggers "new idea" stuff.

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7 hours ago, JSHarris said:

They also seem to work well (some say better) when mounted vertically, which makes sense as that may then allow better convection and that in turn may help to reduce icing in damp weather.

 

Also, better thermal IR radiation from the general environment. Normally the ground is warmer than the sky, except the hot patch round that fusion reactor up there.

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As soon as I see 'works like a refrigerator in reverse' I get annoyed.

They work the exactly the same as a refrigerator, just that the cold bit is outside and the warm bit inside.

  • Haha 1

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They will probably have to drop the "solar" bit, too, as the last bunch to try and market these as being some form of solar collector system ended up being told to remove this from their advertising, I believe.  As I mentioned earlier, it's be nice to see some solid data on how well these work.  When mounted vertically on a wall they apparently work quite well, but no one (AFAIK) has been able to provide hard performance data under defined conditions so far, which seems a bit odd, given that they are quite popular in Portugal and Spain.

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4 minutes ago, JSHarris said:

popular in Portugal and Spain.

Like the UK, both those countries have different climate regimes.  So may work well in one part, and be rubbish in another.

There is nothing fundamentally wrong with them, and would suit my house quite nicely (I have a bit of space below the bedroom windows) and should be easy to fit.

But I really cannot see any advantage over a small ASHP to be honest, which would be even easier to fit as it sits on the ground.

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1 minute ago, SteamyTea said:

But I really cannot see any advantage over a small ASHP to be honest, which would be even easier to fit as it sits on the ground.

 

When I looked into them years ago, I went down to Southampton to visit a UK importer who was looking at selling them here, and who had a demonstration installation fitted to their industrial unit.

 

The main advantage they had for heating water is that the refrigerant heat exchanger is inside the water cylinder.  This improves the efficiency a bit, enough to be able to get hot water at around 55°C to 60°C without incurring a big hit on the COP.  They also have the advantage of lower power consumption overall, because there's no fan or water circulating pump.  Overall, there seems no doubt that they work well under the right conditions, the problem was that we couldn't get any hard data out of the Portuguese manufacturer at all, they just refused to provide it.  This was the reason the chap in Southampton pulled out of selling them in the end.

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