thermodymic panel for water heating

suffolkpumpkin

Good morning ALL!

Dear MSE, I was wondering if I can tap into your wast knowledge on everything for some advise :-)
Our water is heated by oil with an occasional top up on the economy 7 during summer months.
Yesterday we had a quote for the thermodynamic panel installation which will heat our water all year around
by one of the local companies. The cost of installation is around 9K (includes everything: panel, labour and 200l new water tank). But then under the proposed goverment schemes we'll get some money back on the annual basis (no less than £400 we were told). The panel's life is 20-25 years.
Does anybody out there is using one of these panels? How quickly it will heat the water in the winter? As we had last couple of winters really cold, my husband is very sceptical that we'll have enough hot water when we needed it most.
Any advise or experience on the thermodynamic panel use will be very much appreciated.

Many thanks!
P.S. We live in the listed building and it's tricky to install anything out of the "building character", solar panels etc.
But these things you can paint over, so they can blend in.

Fruit_and_Nut_Case

suffolkpumpkin wrote: »

But these things you can paint over, so they can blend in.

I'm pretty sure they could be painted but am also pretty sure that this would affect their heat-gathering efficiency*. Black=Good; White=Bad.



*Ye cannae beat the laws o' physics.

grahamc2003

suffolkpumpkin wrote: »

Good morning ALL!

Dear MSE, I was wondering if I can tap into your wast knowledge on everything for some advise :-)
Our water is heated by oil with an occasional top up on the economy 7 during summer months.
Yesterday we had a quote for the thermodynamic panel installation which will heat our water all year around
by one of the local companies. The cost of installation is around 9K (includes everything: panel, labour and 200l new water tank). But then under the proposed goverment schemes we'll get some money back on the annual basis (no less than £400 we were told). The panel's life is 20-25 years.
Does anybody out there is using one of these panels? How quickly it will heat the water in the winter? As we had last couple of winters really cold, my husband is very sceptical that we'll have enough hot water when we needed it most.
Any advise or experience on the thermodynamic panel use will be very much appreciated.

Many thanks!
P.S. We live in the listed building and it's tricky to install anything out of the "building character", solar panels etc.
But these things you can paint over, so they can blend in.

We had a quote for these panels last week - first time I'd heard of them. My quote (including new electric circuit, new tank, conversion to pressurised system (they only work that way), relocate tank to loft, and a single panel) turned out 25% less than yours (plus then there's the rhpp of £300 iirc to take off).

It's not like normal (passive) solar thermal. This is a heat pump system - the panel is just where the heat is gathered by the fluid being pumped around. So there are running costs to power a compressor. The advantage of that over normal solar thermal is the water in the tank gets hotter - to 55c (which is what my thermostat is set to), and it gets there quicker - they claim 1.7 to 2.9kW, with the top of the claim being almost as good as an immersion. I'd need more than their claim to believe it! At 7C, they claim a cop of 5ish, and running costs of £10 a month typically.

It works on radiant energy - and absorbs ambient heat above -20C, whatever the weather. There are questions though - whether it freezes over, and if it does, whether it matters,; also the cop values at lower temperatures aren't stated in the guff I got. If situated in the direct sun, I expect it heats the dhw for a very low cost. I wouldn't have the concern of your husband - I'd expect this system to always get the water hot (at least while the ambient temperature stays above minus 10C).

Whether you'll get £400pa rhi is still up in the air. My tank is on its last legs so I'll have to get some sort of new system, but for me, the jury's still out on this one. Go for it if you want to be a trailblazer. If you paint it, you'll lower the performance, since matt black is the ideal (lack of) colour.

On another point - no idea why you are heating your dhw with oil when you have e7, which is probably 1/3rd of the cost!

suffolkpumpkin

thank you, Fruit and Nut Case,
it's a good tip :-) I didn't think of that one!

but what I'm really after is the info about their performance through the winter months. Apparently, they work above -15C, but obviously their heat production correlates with ambient temperature. It is not advisable to install them inside the house, due to the condensation run off. But, if outside is 0C or say -5 C or below that at night, will these panels heat 200L of hot water to +55C overnight? We have five people household and everybody like their showers in the mornings....
I googled the technology as much as I could, but not much info from the actual users :-(
If anybody out there who has these thermodynamic panels can share their experience, it would be very helpful for us to make our minds up. With the energy prices going up and up, it makes sence to invest into green technologies, they just have to suit your needs...

Many thanks :-)

suffolkpumpkin

Thank you, it was very useful indeed.
We were quizzing this chap about the winter months. I don't think the panels themselves will freeze over: the chemicals inside the panel freezing T is 70C (I think). But, what matters to us how much they'll slow down heating the water. And this info I could not get in "black and white" neither from him or the internet. Unless I'll start digging really deep (i.e. name of the chemicals and hit the PubMed or similar :-(
It wouldn't be nice to get up on the frosty morning and find out that there is not enough hot water having paid all these moneys :-(

grahamc2003

suffolkpumpkin wrote: »

Thank you, it was very useful indeed.
We were quizzing this chap about the winter months. I don't think the panels themselves will freeze over: the chemicals inside the panel freezing T is 70C (I think). But, what matters to us how much they'll slow down heating the water. And this info I could not get in "black and white" neither from him or the internet. Unless I'll start digging really deep (i.e. name of the chemicals and hit the PubMed or similar :-(
It wouldn't be nice to get up on the frosty morning and find out that there is not enough hot water having paid all these moneys :-(

Dig as deep as you want - I simply think there's little or no experience of these things yet - they are really a new application of old technology. At lower ambient temperatures, the cop become lower, and somewher (guessing) about -5C the cop will go below 1, meaning it's better to turn the thing off, and simply use the built in immersion heater (which ensures you'll always have hot water, even if the ambient drops to -50C).

By freezing over, I meant getting a layer of ice. Obviously, with a big flat panel at about -20C (that's the working fluid temperature in it), there's a possibility of ice deposition on it when the temperature is below about 10C, or simply freezing any rain which falls on it. It may be that clear ice isn't much of a problem, but possibly a light layer of white frosty ice may well be. Problem is, we don't know because not many of these have been installed yet.

Unfortunately, these questions aren't ones you'll get currently sensible answers to from installers/system sellers since there's virtually no statistically significant data on them yet in the uk's climate.

suffolkpumpkin

thanks grahamc2003 for your comprehensive answers.

would you think you'll be installing one of these?

I simply can't make my mind up. On one hand, it seems straight forward thing to use, on the other, I feel I don't have complete info about performance in the past...

Oh, well, I'll think about it for a bit longer....

thanks again

Kernel_Sanders

Is anyone else having trouble using the 'quote' facility? It's just bringing up a blank reply window for me.

Sorry, I don't get this at all. The OP asks But, if outside is 0C or say -5 C or below that at night, will these panels heat 200L of hot water to +55C overnight?
So when it's freezing cold and the Sun is on the other side of the planet, you are expecting this panel to heat water overnight at all, let alone to 55 degC?

suffolkpumpkin

Kernel_Sanders wrote: »

Is anyone else having trouble using the 'quote' facility? It's just bringing up a blank reply window for me.

Sorry, I don't get this at all. The OP asks But, if outside is 0C or say -5 C or below that at night, will these panels heat 200L of hot water to +55C overnight?
So when it's freezing cold and the Sun is on the other side of the planet, you are expecting this panel to heat water overnight at all, let alone to 55 degC?

These thermodynamic panels operate on the different principle from solar panel. They use heat exhange rather than solar energy. It's a bit like a fridge but with the opposite effect. You can google "thermodynamic panels".

no Sun, freezing cold but +55C 200L water tank...that would be nice.. wldn't it? :cool: graham2003 was helpful, but I wish I could talk to somebody who's got them already :-( Wrote to my German friends, Germany is a bit ahead on all these things and it's cold there too!

jetski690

Hi Suffolkpumpkin, I can guess by your username where your from and as I'm from the same region I'm guessing the quote you had might be from the same company I had round, I was quoted £6965 for the same thing the lowest there allowed to sell it for so I was told, the technology is very much in it's infantsy especially here and although I can see how it works there's just too many unknown questions firstly if like me you were told the government incentive will pay you for 20 years like the solar tariff that seems to be untrue I've found from other sources it's likely to be set at only 7 years and I was also told the pricing should only be around the £3000 mark so be very careful before you proceed.

http://www.guardian.co.uk/environment/2012/sep/21/householders-green-heating-costs

1echidna

It is as well to note that in the event the outside temperature falls to -10C the system just won't work. It is an air source heat pump with a new name.