Air to Water heat pump; house and pool?

(Peter Whitfield) #1

Is it true that you can use a House Air to Water Heat pump to heat your pool too? Do they not run at different rates, etc.

Is the reverse true, also - using a Pool A to W Heat pump, to heat your home, as Pool Heat pumps are (I think) cheaper than House ones. Different outputs of course.

(John Withall) #2

Peter bigger size, less resistance, bigger surface area but slower transit with less resistance? probably about the same with the lower resistance, My calculator doesn't go that low with small pipes but I daresay I could find one but busy with some other stuff.

(Peter Whitfield) #3

Hi, John, Yes, I can feel the outlet into the pool is at a slightly higher temperature. The pipe is 16 mm polyethylene, but come to think of it, it could be better in a bigger size - less resistance, bigger surface area, and slower transit, at little extra cost.

(John Withall) #4

Thanks Peter sounds like your 1deg was a bit of an under estimate. Is that the narrow 5-6mm irrigation pipe or the larger 20-25mm one?

Liz, sorry a bit of a geek here so any more on offer than the one line to help look at your cover and what the pool is made from?

(Peter Whitfield) #5

John, 'Fraid I can't say with any certainty. The pool would be swimmable (26°) some time in July, but now, with the tubing, we would have already turned it down by the beginning of July. It is on a south-facing bank - the soil from the pool excavation, which also serves as a flower garden.

(Liz Prosser) #6

In an enclosed walled garden suntrap!

(John Withall) #7

Liz, expensive sun mat, any more to go on?

What is the pool made from as metal sided above ground pools can loose heat at an alarming rate but in a good situation can also gain it but they are usually un insulated so all gains are lost over night. Is it possibly to insulate it?

Mike, Yes

Peter, what was the normal solar gain without your pipe connected?

(Peter Whitfield) #8

Liz, I made a pool heater from the pipe that you use for garden irrigation. Each length is about 15m and there are about 20 of them. The trick is to make the manifold - I can send you a photo. They lie on that stuff you put on gardens to keep the weeds down, and are under plastic. The water comes from the pool pump. The pool (75m3) gains about 1°C per sunny day (in the Roussillon)

(Mike Kearney) #9

How about a reversible system?

You could heat your pool and cool your house in the summer.

Then in winter, you could heat your house and turn your pool into an ice rink.

Now there's a thought!

(Raymond John Fletton) #10

I hate spell check, that's diviner!

(Raymond John Fletton) #11

Water/water heat exchanger will give around 4,7 kw for 1 kw of electricity. If you have a well, you can ask a water divider (don't laugh, it works!) to estimate the flow rate, then you extract the heat from the water and re-inject the water away from the well so that it heats up to around 13 deg again.
Obviously more suited to underfloor heating but then it is reversible so cools the house in summer!

(Raymond John Fletton) #12

(Liz Prosser) #13

Anyone out there have advice on heating a 15ft diameter on-groud pool,we bought an expensive sun mat last year that was supposed to work but did not, would appreciate any good ideas please (sorry to but-in on your post Peter).

(John Withall) #14

It depends on the unit as some are higher operating temperature so can run usual radiators whereas the pool units and others are lower temperature larger like under floor heating. I am looking for the same reasons as yourself. There are also reversible units so they can cool a hot building in summer and put that into a pool potentially

If you spot any info please come back and discuss it.

(Peter Whitfield) #15

Thanks, John. I would be interested to know the results, as it would fit our situation, though I would most probably have to increase the total radiator surface area.

(John Withall) #16

Ahem, devil is always in the detail, I am looking into this on going as some units for pools work around 5m3/hour flow rate minimum but many are plumbed much faster. If necessary a heat exchanger could be used to take one flow rate available to a different rate for either the pool or home as required.

I am meeting with some manufacturers in march to discuss this very thing. Always interested in anyone who has done this and just because a manufacturer hasn't doesn't necessarily mean it can't be done they may not have thought about it as they would probably prefer to sell more units.