# ground source heat pumps - could you heat a swimming pool?



## goldeneyedmonkey (9 Jan 2011)

Hello all,

Just wondering, as I don't have any plans to build one (not until I win the lottery anyway ), would a ground source heat pump be able to heat a swimming pool? Just a thought I had whilst in the pub and me and a mate were chatting about it. It seems possible to us, what do you think?

Cheers _Dan.


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## 9fingers (9 Jan 2011)

Yes. Would be even more economical if you have economy 7 tariff.

Bob


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## RogerS (10 Jan 2011)

You could also consider a water bore hole to get the heat rather than digging up your garden.


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## Jonzjob (10 Jan 2011)

We have got solar to do our pool. 50 evacuated tubes from company called Navitron, www.navitron.org.uk. We really need another 10.

We investigated ground source heat for the central heating. We have under floor heating heated, now, by a condensing boiler, but when we were checking we had an old boiler (not the misses before anyone asks!). We decided to see if we could get ground source. We have 3000 sq metres of garden, but it is completely landscaped with a lot of mature trees so horizontal was out of the question. So we checked on vertical holes. We woud have needed 2 150 metre deep holes at a cost of about 16000€ :shock: :shock: :shock: :shock: Then we would have to buy the kit to fill the holes and convert the heat! So we got a new boiler. Vertical hole boring is bloody expensive!

If you want more info on heating then it's well worth having a look at the Navitron forum. There are a load of pro plumbers who do a lot of solar and ground source and, like here, are more than willing to help.

There's all sorts of interesting kit on there too. Nowt to do with me, I'm just a satisfied customer... 8) 8)


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## RogerS (10 Jan 2011)

Jonzjob":31kh3dsm said:


> ..... Vertical hole boring is bloody expensive!
> 
> .....)



It depends on the height of your water table. My neighbour who introduced me to the idea only has to drill 50m. He calcuated that at a flow rate of 1 l/sec and a 3 degree temperature difference that he'd get 110,000 kWh per year.

He's sticking in a solar voltaic array and so that makes it even more cost effective. if oil gets any more expensive (currently 67p a litre) then the cost-benefit starts to look even better.


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## dickm (10 Jan 2011)

I know that ground source heat pumps make _economic_ sense compared to using electricity directly, but they don't make much sense in energy terms. The best CoP you are likely to get is between 3 and 4, and in the UK, most electricity is generated with an efficiency of not much over 30%. So you are using 3 units of fossil fuel to generate one unit of electricity to give, at best, 4 units of heat. 
What I keep wondering is how far down into our granite rock it would be necessary to drill to get to where it is sensibly hot; given all the expertise in deep drilling up here, it ought to be a doddle to do


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## RogerS (10 Jan 2011)

But my neighbour is using photovoltaics to supply his electricity..


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## 9fingers (10 Jan 2011)

RogerS":3fm6e21j said:


> But my neighbour is using photovoltaics to supply his electricity..



I should get mine installed next week Roger

Bob


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## johnf (10 Jan 2011)

We have just installed a ground source heat pump commissioned two weeks ago 24 hour heating and hot water very happy with it at the moment. 
It also puts us in line for the RHI scheme later this year

Got to look into PV panels next


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## 9fingers (10 Jan 2011)

johnf":2nqvdup4 said:


> We have just installed a ground source heat pump commissioned two weeks ago 24 hour heating and hot water very happy with it at the moment.
> It also puts us in line for the RHI scheme later this year
> 
> Got to look into PV panels next




What sort of ground area did you need to provide enough energy for a house?

TIA
Bob


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## johnf (10 Jan 2011)

Bob 
we used three 200 mtr long loops flow and return min 1 mtr apart 2 mtr between loops so 600 mtrs of trench in total


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## 9fingers (10 Jan 2011)

Thanks John, 

I thought it would have to be quite extensive. I've not got that much space in the garden.
I'll have to stick with my PV panels.

Bob


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## RogerS (11 Jan 2011)

The other slight downside with ground source is that no matter how good they relay the soil, it will settle and you end up with a garden looking like a furrowed field!


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## misterfish (11 Jan 2011)

We looked at the possibility of using ground source heat pump technology a few years ago but at the time the received wisdom was that it was only effective/worthwhile for use with underfloor heating (as water temperature is not very high) installed in a new build with high levels of insulation. Has technology improved to make retrofit a worthwhile?

I do remember seeing a demo of heat pump technology where a building was heated using heat energy removed from a huge block of ice - working on the basis that the 'ice cube' was always being made colder by the heat pump but being warmed at the same time by the surrounding air. If this sort of thing was practical on a large scale then it could do away with the need for boreholes or large gound loops.

Also, what about air source heat pumps - there was a flurry of info about them a while ago but I've heard nothing recently. I assume this is similar to the 'window box' air conditioning units seen around the world.

Misterfish


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## RogerS (11 Jan 2011)

misterfish":1ai3wimo said:


> .....
> 
> Also, what about air source heat pumps - there was a flurry of info about them a while ago but I've heard nothing recently. I assume this is similar to the 'window box' air conditioning units seen around the world.
> 
> .....



Way way too noisy...


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## Jonzjob (11 Jan 2011)

On a warm day the air source units will give you about the same sort of gain as the ground source, but when the temp drops below about 5ºC it drops quite dramatically, 1 1/2 or 2 times. So it gives least when wanted most... We hear our neighbours motor running if we are in the garden near their house, so not too bad but it must sound in the house.

The other thing is that it blows warm air in the house. I don't know how many remember warm air heating that was all the rage in the 60/70s, but it was found that the temp of the air had to be 1 or 2º higher than the required air temp because of the 'wind chill' factor. I love our under floor heating. As said before, the water temp can get as high as 43ºC on a really cold spell and it gets down to -7 or so here. But normally it runs upto the high 30s to keep the house at about 20ºC. No hot spots from radiators, no wall space taken by radiators, just nice and comfortable everywhere. We also have a large open fire and that is lit most days when it's cold and/or miserable for the cosy factor..


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## johnf (11 Jan 2011)

We are using the existing radiators and are achieving a constant temperature of 20 c which is nice and comfortable .

we do have a good level of insulation

It has been -8 here at times indoors still 20 with the price of oil at 70p should be a good move 

They estimate an anual running cost of £900 thats for a 3000 ft2 property


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## SammyQ (11 Jan 2011)

I thought Mike Garnham was back? If he is, I'm surprised he hasn't weighed in on this...If I recall correctly, as a practicising architect, he was death on ground source heat pumps, describing them as glorified electrical C.H.??

Just my 2 pre-decimal pennies....


Sam


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## 9fingers (11 Jan 2011)

I don't think Mike visits here that often. He is mainly active in the 'new place'

GSHP works and can be cheaper to run in monetary terms than other fuels. Depending you your viewpoint about green issues, the simple running cost is not the only way to evaluate it.

Bob


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## RogerS (11 Jan 2011)

SammieQ":2p8nj2kw said:


> I thought Mike Garnham was back? If he is, I'm surprised he hasn't weighed in on this...If I recall correctly, as a practicising architect, he was death on ground source heat pumps, describing them as glorified electrical C.H.??
> 
> Just my 2 pre-decimal pennies....
> 
> ...



Here heat-pumps-t38424.html?hilit=ground%20source%20heat


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## SammyQ (12 Jan 2011)

Cheers Roger,  . 
Sam


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## Pond (12 Jan 2011)

AT LAST!

I know nothing about woodworking (yet :wink: )but I happen to be fully qualified in this field and have been an air conditioning and refrigeration engineer for the last 26 years.

OP: yes of course you could. Heat pumps have been the weapon of choice for swimming pool heating for a while. A ground source heat pump is just a heat pump which collects it's heat from the ground instead of the air. 
Heating a swmming pool is a little more complicated in this instance because by taking the heat from the ground around it and transferring it into an underground pool, you are putting the heat back to where it came from, sort of!! It would work though

Gonzjob is confusing air source heat pumps with air-to-air heat pumps. The information given by this person is wrong in every respect.

Ground source heat pumps are now (or will be very very shortly) obselete. Sorry to the person who has just had one commissioned, but it is a fact.

Air source heat pumps are the new 'in thing', as they are far more efficient than ground source and much much cheaper to install cos you don't have to run 3 miles of pipework under your garden!

The main problem with ALL this new technology is that, at present, any heat pump will not heat water to a high enough temperature to use on a standard radiator system, make retro-fitting impossible. Believe me, if retro-fitting was possible I would be a millionaire by now!! All heat pumps, except air to air with warm air fan/coils, are only used for underfloor radiant heating. 

I won't bore you anymore with this, as I'm starting to bore myself.


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## big soft moose (12 Jan 2011)

Pond":3r7xaqvv said:


> any heat pump will not heat water to a high enough temperature to use on a standard radiator system, make retro-fitting impossible. Believe me, if retro-fitting was possible I would be a millionaire by now!! All heat pumps, except air to air with warm air fan/coils, are only used for underfloor radiant heating.
> 
> I won't bore you anymore with this, as I'm starting to bore myself.



what sort of temperature water can you achieve ?

I'm shortly going to be looking after a campsite where the showers are currently supplied via solar heating , and one of the common complaints is that they are disapointingly luke warm - just wonderring if a GS or AS heat pump might be a realistic alternative.

Also what kind of cost are you looking at for an AS installation ?


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## Pond (12 Jan 2011)

You can use either GS or AS to heat domestic hot water, as the required temperature is only 45-60 deg c. They are usually fitted with a 'top up' heater, either PV, or immersion to reach higher temps. 

I don't know specific costs as we do not (at present) buy or install this technology. It is being targeted at plumbing and heating engineers at present, unfortunately. 

I do know that the government is shortly due to initialise a very generous grant based incentive scheme (all about being seen to be green). I've heard rumours that some companies are, or will be offering free issue equipment and installation if the customer signs over their grant, as this scheme is not going to be a once only payment, but an ongoing deal.

You would have to do some serious sums to find out if it would be cost effective to just heat domestic water, though.


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## johnf (13 Jan 2011)

Pond read this

Here at Ice Energy we've been huge advocates for Ground Source Heat Pumps because of their greater efficiencies over their air source heat pump cousins.

However the ground source solution is not appropriate for everyone, often due to space considerations, yet we have seldom recommended air source in the past because we couldn't find a product which came up to our exacting demands and was suitable for the British market - that was until Mitsubishi brought out their ground breaking air source heat pumps.
While admittedly still not quite as efficient as ground source, giving around 320% efficiencies rather than 400%, it is a huge advancement and a product which stands head and shoulders over its competition.


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## RogerS (22 Oct 2011)

stuartrivchun":2wds8tzb said:


> yes you can definitely heat a swimming pool using Ground Source Heat Pumps.Ground source heat pumps can be applied to a wide range of both domestic and commercial applications, ranging from heating a small residential property with a swimming pool to heating and cooling a large commercial building like a hotel. If a house, commercial property or swimming pool need heating or cooling, then a ground source heat pump can help to reduce running costs*. GeoPro Design *offer a wide range of heating and cooling solutions, from providing an environmentally friendly solution to your domestic hot water (DHW) requirements through to a fully integrated heating and cooling system that can be controlled remotely




*SPAM !!!!!!!*


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## angelboy (22 Oct 2011)

Jonzjob":mgj31wou said:


> We have got solar to do our pool. 50 evacuated tubes from company called Navitron, http://www.navitron.org.uk. We really need another 10.





What size is your pool?

Is it covered?


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## bosshogg (22 Oct 2011)

goldeneyedmonkey":3a6o1vga said:


> Hello all,
> 
> Just wondering, as I don't have any plans to build one (not until I win the lottery anyway ), would a ground source heat pump be able to heat a swimming pool? Just a thought I had whilst in the pub and me and a mate were chatting about it. It seems possible to us, what do you think?
> 
> Cheers _Dan.



The answer to your question is both yes and no. Yes if the ground conditions are right, and no if they are not. 
Replacing an inefficient boiler at Castle Howard, in Yorkshire, is well documented. The unusual angle employed, was connecting the pump connected to the heat exchange loops laid in a nearby lake, as opposed to excavating large areas of land, to what is an Historical Listed Building. 
For-by the upgrade of the heating, considerably upgrading generally, in line with conservation of heat loss, was undertaken. The investment, which wasn't cheap, was recovered fairly quickly in relevant terms, relevant that is to the longevity of the building.
Now I'm not by any stretch of the imagination, supportive of those privileged enough to live in such high echelons as this, but ground heat sources, have yet to be fully exploited.
Not only that, but heat exchange is another fundamental win win scenario, in the offing. Think about it, we continuously output, from buildings of all descriptions, heat, either in the form of spent air, steam from washing machines, tumble dryers and showers/baths, which i know is not steam, but could also be described as condensate'd steam :lol: :lol: :lol:, anyway, if these sources and any others not mentioned, could be intersected with a heat exchanger, the results would be a partial everlasting loop of heat saved. Oh I know this cannot be everlasting, but if it reduced energy consumption by 50%, it would be very beneficial. Now you won't see that in any of the energy companies so called sustainable programmes...why?
Cheers...bosshogg 


> Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment. Most people are even incapable of forming such opinions.
> Albert Einstein (hammer)


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## RogerS (22 Oct 2011)

Yebbut...don't all these heat-extraction systems require energy ...specifically electrical energy...and that the critical factor is the COP....ie how much heat you extract against how much you have to shell out in electricity. It's OK if, like my near neighbour, he has also installed a huge solar array that generates many kW to drive his vertical bore hole heat source .......


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## bosshogg (22 Oct 2011)

That leads to a bit of speculation on my part, Oh! and the amount of energy required from the pump is negligible compared to the heat gains. My speculation, is there any boffins out there, with an understanding of air pressure at roof levels, Archimedes screw compression, compressed air and theoretical modelling...I have a theory.
Cheers...bosshogg  


> [The important thing is not to stop questioning. Curiosity has its own reason for existing. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day. Never lose a holy curiosity.
> Albert Einstein (hammer) /quote]


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## RogerS (22 Oct 2011)

bosshogg":2ofmeyuk said:


> That leads to a bit of speculation on my part, Oh! and the amount of energy required from the pump is *negligible* compared to the heat gains. My speculation, is there any boffins out there, with an understanding of air pressure at roof levels, Archimedes screw compression, compressed air and theoretical modelling...I have a theory.
> Cheers...bosshogg
> .....



3 kilowatt out for 1 kilowatt in is hardly 'negligible', surely?


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## johnf (22 Oct 2011)

All I can say is that installing a ground source heat pump for our CH and hot water needs has cut our energy bill by 65% 

Also we have now got a 3,5 kwt solar panel array which will produce some of the power needed and more than enough 
FIT cash to pay for all of our energy bills for the next 25 years .

I rest my case 
PS and I haven't mentioned the renewable heat incentive that kicks in oct 2012 that we qualify for and will give us more cash for 20 years .


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## RogerS (22 Oct 2011)

That's precisely my point, John. To make ground source heat pumps become economic, you MUST provide the electricity yourself.


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## 9fingers (22 Oct 2011)

I cannot see why you say that Roger.

1Kwh of electricity (say12p) fed into a electric fire will give you 1kWh of heat, Feed 1kWh into a heat pump with say a COP of 3 and you will get 3kW out ( and possibly a bit more waste heat from the motor) so that is 4p per kWh of heating.

Bob


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## RogerS (23 Oct 2011)

It was the use of the word 'negligible' I was commenting on, Bob.


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## 9fingers (23 Oct 2011)

RogerS":v4gqzike said:


> It was the use of the word 'negligible' I was commenting on, Bob.



Roger, The part of your coment that I did not follow/agree with was this:-



RogerS":v4gqzike said:


> To make ground source heat pumps become economic, you MUST provide the electricity yourself.



Bob


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## bosshogg (23 Oct 2011)

Unfortunately Rodger has taken negligible out of the statement I made "the amount of energy required is negligible compared to the heat gains" 
Now all of life is a trade off you trade off work done to benefits achieved and that applies to all things apart from what we gain from nature. 
All the energy we use comes from the Sun, whether it's oil (hydro carbonation), oxygen (more correctly absorbing carbon and giving off oxygen - photosynthesis) or ground source heat (absorption of the Suns energy, in a heat collection mass - Earth) and electricity, whether produced from burning the oil or it's symbiont natural gas, wind - from turbines, nuclear fuel (to be fair, all the heavy elements found on Earth came from other stars - Supernova's), all are provided to us by the Sun. How we (Homo Sapiens) charge for these provisions, that's another matter...bosshogg


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## gregmcateer (23 Oct 2011)

goldeneyedmonkey":15xtw1nf said:


> Hello all,
> 
> Just wondering, as I don't have any plans to build one (not until I win the lottery anyway ), would a ground source heat pump be able to heat a swimming pool? Just a thought I had whilst in the pub and me and a mate were chatting about it. It seems possible to us, what do you think?
> 
> Cheers _Dan.



Dan,

Although a bore hole ground source heat pump will technically heat a pool, the problem is that if you use a pool year round, the ground around the bore hole doesn't get a chance to 'recover', so the heating gets less and less efficient.

Sorry about that!

Greg


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## johnf (23 Oct 2011)

RogerS":108f37xb said:


> That's precisely my point, John. To make ground source heat pumps become economic, you MUST provide the electricity yourself.


Roger the economics of my heat pump are that it is saving me a huge amount on my heating /hot water bill it doesn't matter where the power comes from 
The panels only make a good situation better


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