Using Pv To Heat Swimming Pool

A potential customer has  a small open air swimming pool in his garden. He shuts it down over winter, but was considering how to reduce the leccy bill for spring / early summer when he fires it up again. He was thinking of using battery storage charged up by PV over winter to take the sting out of bringing the pool upto temperatrure. But the pool which uses 4kW of heating and takes 10 days to get up to temperature running 24/7, would need some firkin big batteries!! So I'm looking for alternative ideas, of which there are 2 that spring to mind :-

1/ Use PV to run existing pool heating and pumps via solar PV immersun type gadget and a few relays etc , so that system continues to run through winter whenever there is sunshine

2/ Use Pv to power water heater dangled straight into pool, so we avoid wasting energy on the pumps. For this option I was considering finding 12/24v immersion heaters to avoid all the obvious nastiness of of 240V and water

Now I'm not particularly familiar with Swimming pools so I'm after a few opinions and good sources of further readings with regards to the following

a/ Suitable extra low voltage heating elements

b/ potential issues with the existing swimming pool controls should we go with plan 1

Use the solar PV to drive an air source heat pump. Plenty of them sold specifically for heating swimming pools.  The COP should be high as the output temperature needed is quite low.

A bigger (than needed 24/7) heater so it can heat more in the daytime and less or not at all at night.

that's a thought, thermodynamic is very popular aswell at the moment.

Not that I know anything about PV, but you would probably need an array 10 times the size of the pool to heat it ?

solar thermal?

that would be way more efficient for what you want,

thats how most of the pools I saw in NZ were heated,

Why not use a solar hot water system to heat the pool rather than a PV system?

septiclecky said:

Why not use a solar hot water system to heat the pool rather than a PV system?

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:C

Canoeboy said:

@Binky - You need to get solar thermal registered :slap

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I do solar thermal,

do you want a quote???  

have been looking at wood burning pool heaters, but customer isn't keen. promlem is he's on the edge of an AOAB, which is a shame cos he has a field big enough for 200kW. But planning is so tight they made him take down a shed and get rid of a vegtable plot (neighbours must have grassed). Personally I think solar thermal is the way to go, but he's keen on PV for some reason.

jaysus, with that amount of land he wants to go ground source, 

binky said:

...an AOAB, which is ...

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What is an AOAB when it's at home?

I read it as some form of

Area of Outstanding Natural Beauty or something like that,  :C

Still none the wiser!

http://goo.gl/maps/jh1Ag

in the map its the building site next to river, most of the land is field which due to location can't be touched.

Customer already had Ground source for house - put in by previous owner, but dozy twot didn't do swimming pool. In short house is all electric, with no gas supply, so customer is very keen to reduce leccy bills big time!

Would love to go thermal, just don't have the time.

PV really isn't the answer, not on it's own anyway. Sure use it to power a few pumps, filters etc....

Solar collectors is the best way. (someone else mentioned it earlier, the same as a solar hot water system)

I have a 20 tube system to heat a 180lt tank to 60c and I had to fit a bypass valve to a heat dump due to the amount of heat these things generate.

Obviously 180lt isn't much compared to a swimming pool but install 3 or 4 x 20 tube collectors and I'm sure it'll get to 26c pretty quickly. Plenty of tools out there to calculate it anyway..

Does your client know the difference? maybe someone just told him to heat it with solar and he immediately thinks PV?

The client has ambitions to go 'off-grid' but retrofitting enough systems to achieve that isn't really feasible. The really unfortunate thing is that he has the land, but AONB status means he can't use for a suitable array - thermal or PV. They even made him get rid of a small vegetable plot and shed that was just over the line into the AONB. He does have some good sized roof spaces, but just not in a handy spot to heat the pool without digging up garden paths, paving slabs etc etc.

One of my customers has the same problem with AONB, they have asked told them to remove the greenhouse and treehouse for the 9 year old son  

This is their back garden



You can see the greenhouse through the trees, with the treehouse to the left. Good news was they retro applied for planning permission for the greenhouse which has been allowed, but the treehouse has to be removed.



This is used to help heat the swimming pool



The other expense was filling the pool, it was costing over £1500 in water rates at their other properties so at this one (also due to the remote location) they had a bore hole sunk for fresh water, i know its about 100m deep as we had to calculate the supply for the pump.