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rolandh
27-09-2008, 10:09 PM
Hi All
I hope somebody can help me in the design of a heat pump for my pool? I have got a 18000 Btu heat pump air conditioner. I would need some advice in connectin a heat exchanger onto the unit. I wasd thinking in using a PE4 unit from Onda heat transfer solutions. All help will be highly appreciated.

airefresco
27-09-2008, 10:40 PM
How big is the pool?

Personally I wouldnīt bother trying to make one. Just buy a proper one and be done with it.

If you really want to do it then, that PE4 is and evaporator and you need a condenser. Also it doesnīt say on there what thatīs made from. If you can, you want a titanium condenser. The pool chemicals will eat through copper. Youīll also need some sort of a safety, like a flow switch or something, so if your pool pump fails the heatpump stops. You could just use the HP switch in the air-con unit you have (assuming it has one), but itīs better to stop it before the pressures get high enough to trip it.

nevgee
27-09-2008, 11:03 PM
copper is ok with swim pool water so long as the ph is kept to 7.4 +/- 2 and the free chlorine and combined chlorines are kept in balance.

rolandh
28-09-2008, 08:01 AM
It is a small pool of +-12000 Litres andit is also a salt water pool. To buy a unit in South Africa ia very expensive. Also, why would I need a condenser I already have the condenser with compressor from the Ac unit? As far s I know , I wwill substitute the inside blower (evaporator) with a heat exchanger.

nike123
28-09-2008, 12:58 PM
Swimming pool heat exchangers should be from materials and cleaning ability like this one (http://www.ejbowman.co.uk/products/SwimmingPoolHeatExchangers.htm). Also, you need a flow switch to stop the compressor/heat-pump when there is no enough flow (diferential pressure).

nevgee
28-09-2008, 02:10 PM
Forgive me for seeming to be stupid here, but I think you'll need a condenser for the pool water heat exchanger ... not an evaporator. How else will you be able to reject heat into the pool water?
The evaporator will be at the air source.

Please retract my previous comment about using copper, which is ok with fresh water but not if the pool water is salt water. You'll need a cupro nickel heat exchanger or simillar if you're to limit corrosion problems.

nevgee
28-09-2008, 02:15 PM
you can get details of co axial heat exchangers at these sites

http://www.wieland.de/internet/index.jsp

http://www.coaxial-coils.com/Cupronickel-coaxial-heat-exchanger.htm

airefresco
28-09-2008, 10:50 PM
A company that used to be here were selling heat pumps made in South Africa for 1000€. I see if I can find out what make they were, iīm sure you would pay a lot less than that, as you are in South Africa. I donīt know if they were any good though.

hendry
29-09-2008, 02:17 AM
Hi All
I hope somebody can help me in the design of a heat pump for my pool? I have got a 18000 Btu heat pump air conditioner. I would need some advice in connectin a heat exchanger onto the unit. I wasd thinking in using a PE4 unit from Onda heat transfer solutions. All help will be highly appreciated.

as far as i remember, the heat loads come in 2 parts.
1. evaporation losses thru the surface which includes wind load;
2. circulation rate of the pool.

the circulation rate is practically governed by the desired turbidity level of the pool. there is 4 hrs, 8 hrs and so on.

next, you have to decide the temperature you want; that very much form the heat pump capacity in a nutshell.

i hope it helps you.

"it is very satisfying when you find crowds dip into the hot pool you designed." :D

Fire Fly
23-09-2010, 10:14 AM
why not just get your self a custom designed heat pump for your pool? it save you alot of time and effort

desA
23-09-2010, 10:50 AM
why not just get your self a custom designed heat pump for your pool? it save you alot of time and effort

Welcome, FireFly.

Are you a heat-pump designer operating in SA?