Air source heat pump - heat pool and cool house
Discussion
It's possible, but a waste of time and money in the UK.
When it's hot enough in the UK to need air conditioning, the pool will be warm enough from the sun (unless it's indoor) - and with an output of say 20kW it would be like living in a cold store when you want to heat the pool.
Depending on the size of the pool (and heat pump) a unit should be under three thousand pounds.
Post back if you need any more help.
When it's hot enough in the UK to need air conditioning, the pool will be warm enough from the sun (unless it's indoor) - and with an output of say 20kW it would be like living in a cold store when you want to heat the pool.
Depending on the size of the pool (and heat pump) a unit should be under three thousand pounds.
Post back if you need any more help.
I have a heat pump book updated in the early seventies (after the first oil price shock), and many very energy efficient systems were devised........and not implemented because the return on capital was too low.
With higher energy prices and lower capital cost (Chinese manufacturing), heat pumps or other forms of heat recovery can now be cost effective, but the same problems of overcapitalisation can still occur. ie spend too much for a small return.
On the face of it chucking hot water down the drain from a bath is throwing money away, but it's difficult to reclaim the energy. However there is an interesting device for a shower where the drain water is used to heat the incoming cold water, but have you ever come across anyone with one?
Edited by jaybkay on Saturday 20th March 21:47
jaybkay said:
but the same problems of overcapitalisation can still occur. ie spend too much for a small return.
Edited by jaybkay on Saturday 20th March 21:47
Very few houses in NZ hav oil or gas fired central heating. Most are log burner or Heat pump.
There pretty damned efficienct (4:1 or so) and now work OK down to about -15 if you get the right one, expensive to install especialy for multi room setups and eve a good one (ours i s 7kw) cant measure up to a nice log burner once its going
There pretty damned efficienct (4:1 or so) and now work OK down to about -15 if you get the right one, expensive to install especialy for multi room setups and eve a good one (ours i s 7kw) cant measure up to a nice log burner once its going
NoelWatson said:
jaybkay said:
but the same problems of overcapitalisation can still occur. ie spend too much for a small return.
Edited by jaybkay on Saturday 20th March 21:47
Hence a heat pump running at 300% will be something like 100% efficient overall when the power comes from a coal fired station (losses can be 66%). Under NZ conditions we can run underfloor heating at 500% efficiency, and even in the UK a swimming pool heat pump could be 5 or 6:1 efficient.
All heat pumps lose efficiency as the temperature gradient gets larger, so using them in the UK for radiators usually doesn't justify the expense.
NoelWatson said:
Was researching pool heating options and was wondering if people make a pool heater that uses the "waste" cool air to cool the house in the Summer?
The simple answer is no, I've never seen anything on the market that does exactly what you want.But, I have seen heat pumps in conservatories taking the heat from the conservatory and using that as a heat source, blowing to outside, so the HP was like an extract fan in the conservatory. Not ideal though.
You could possibly make up a duct system that could direct cold air from the heat pump into the house, but again not too good or easily controlled.
Maybe using an air conditioning system for the house with a water cooled condensor which you could run the pool water through, would be the best thing to consider, but they are pretty rare in this country too!
jaybkay said:
When it's hot enough in the UK to need air conditioning, the pool will be warm enough from the sun (unless it's indoor)
My inlaws had outside pool and the above is definitely not correct! And their pool was in a sun-trap. It takes many days of hot weather for the pool to get to 22C (which still feels cold) and that's with putting a cover on it at night too.
Some things to bear in mind for the UK:
Look carefully at Heat pump efficiency (what temperatures does it work well at?)
What about winter ?
Electricity prices are expensive during the day when efficiency is greatest
You can still get some fantastic deals on Economy 7 - simple electric heater works well heating the pool overnight and running the filter/pump on cheap rate as well
Look carefully at Heat pump efficiency (what temperatures does it work well at?)
What about winter ?
Electricity prices are expensive during the day when efficiency is greatest
You can still get some fantastic deals on Economy 7 - simple electric heater works well heating the pool overnight and running the filter/pump on cheap rate as well
Simpo Two said:
jaybkay said:
Under NZ conditions we can run underfloor heating at 500% efficiency
What on earth does '500% efficient' mean? I know NZ is a magical place but I didnt think they'd discovered perpeptual motion!Simpo Two said:
John MacK said:
500% effiiency means, for example, 1Kw of electricity to run the Heat Pump will give ~(up to) 5Kw of heat output.
Ah, so the other 4Kw is energy (heat)from the air?That seems like a good way to cut fuel bills by 80% - but I suppose it won't work in the UK...
http://www.altherma.co.uk/binaries/UKEPLEN09-724_D...
with solar panels:
http://www.altherma.co.uk/binaries/UKEPLEN09-726_S...
Simpo Two said:
I always think what a waste it is to empty a bath of hot water down the drain - I want to filter it and put it back in the HW cylinder! But I expect the kit to do it would cost about £2,000...
jaybkay said:
On the face of it chucking hot water down the drain from a bath is throwing money away, but it's difficult to reclaim the energy. However there is an interesting device for a shower where the drain water is used to heat the incoming cold water, but have you ever come across anyone with one?
Some kind of heat exchanger connected to your cold water inlet would make good sense, as jaybkay said. Snag is that fitting one retrospectively would probably be a real nuisance, as it would need to connect from the main drain outlet from the house (to recover the heat) to the main water inlet (to heat the incoming water). To do this could possibly involve replumbing large amounts of pipework, and it would be much easier to install on a new-build than an existing house. But if you could increase the incoming water temperature by only a couple of degrees, it would reduce energy bills.
A good idea, I'm sure. ROI would be the critical question.
Oli.
For those worried about heating in winter bear in mind that a lot of Scandinavian houses use this technology, air source heat pumps are the most affected and they operate down to -19. Not as efficiently of course and any heat pump system is only a part of the whole when it comes to efficiency (insulation, radiator efficiency etc).
Secondly, although electricity prices in UK are more expensive than NZ for example I can only foresee them getting more expensive, not cheaper. Add forthcoming 'green' taxes, offset costs of (re)developing Nuclear, buying in electricity from oil/coal fired stations with the expected long term rise in fossil fuel (it is finite, after all) and it'd be fairly safe to say fuel in whatever form isn't going to get much cheaper.
Now plan it out over the lifetime of the system (the air source heat pump technology in Scandinavia was developed towards local authority specs - 25yr lifespan etc) and take off the 30% govt, grant from the initial purchase price and in my case, it panned out that it would pay for itself in 7-10 years - and that's if fuel/electricity prices stayed the same. Of course, it's a long time to wait, but two things - firstly, if you sell your house I can see the installation of a system like this to be only beneficial to your sale in terms of both speed and price. Secondly, once those 'pay back' years have gone by then you're managing to heat your house and water for the cost of keeping a pump turning, not bad.
Leveraging the efficiencies in the form of insulation only makes it better, however spending 5K getting a wind turbine doesn't make much sense as thn you're looking at about 25-30 years payback time, so unless you want to go completely off-grid then best leave that option alone.
Secondly, although electricity prices in UK are more expensive than NZ for example I can only foresee them getting more expensive, not cheaper. Add forthcoming 'green' taxes, offset costs of (re)developing Nuclear, buying in electricity from oil/coal fired stations with the expected long term rise in fossil fuel (it is finite, after all) and it'd be fairly safe to say fuel in whatever form isn't going to get much cheaper.
Now plan it out over the lifetime of the system (the air source heat pump technology in Scandinavia was developed towards local authority specs - 25yr lifespan etc) and take off the 30% govt, grant from the initial purchase price and in my case, it panned out that it would pay for itself in 7-10 years - and that's if fuel/electricity prices stayed the same. Of course, it's a long time to wait, but two things - firstly, if you sell your house I can see the installation of a system like this to be only beneficial to your sale in terms of both speed and price. Secondly, once those 'pay back' years have gone by then you're managing to heat your house and water for the cost of keeping a pump turning, not bad.
Leveraging the efficiencies in the form of insulation only makes it better, however spending 5K getting a wind turbine doesn't make much sense as thn you're looking at about 25-30 years payback time, so unless you want to go completely off-grid then best leave that option alone.
Edited by andy_s on Monday 22 March 15:25
zcacogp said:
Simpo Two said:
I always think what a waste it is to empty a bath of hot water down the drain - I want to filter it and put it back in the HW cylinder! But I expect the kit to do it would cost about £2,000...
jaybkay said:
On the face of it chucking hot water down the drain from a bath is throwing money away, but it's difficult to reclaim the energy. However there is an interesting device for a shower where the drain water is used to heat the incoming cold water, but have you ever come across anyone with one?
Some kind of heat exchanger connected to your cold water inlet would make good sense, as jaybkay said. Snag is that fitting one retrospectively would probably be a real nuisance, as it would need to connect from the main drain outlet from the house (to recover the heat) to the main water inlet (to heat the incoming water). To do this could possibly involve replumbing large amounts of pipework, and it would be much easier to install on a new-build than an existing house. But if you could increase the incoming water temperature by only a couple of degrees, it would reduce energy bills.
A good idea, I'm sure. ROI would be the critical question.
Oli.
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