Outdoor Swimming pool, looking for heating adivce?

yrag male

Iron giant. Sorry to hijack the thread. Where did you buy your black hose pipe from? Please and thank you

Gary

IronGiant

Sorry guys, I don't visit this section very often   I'll try and get something together today or tomorrow.  I use it to heat a 10 foot Intex Easy up pool.

IronGiant

Can't remember where I got the hose pipe from. I bought 50m to start with and then supplemented it with irrigation hose which is cheaper: e.g: http://www.amazon.co.uk/garden-outdoors/dp/B009Y3DVEQ

IronGiant

OK, I started off with two 50mm thick 2.4m by 600mm sheets of polystyrene, which I laid side by side and covered in foil.  These were then framed with 2" by 4" treated timber to box them in.  Two holes were drilled above the polystyrene at one end and the hose fed through and coiled up inside the box.  I'd like to claim it was a perfect flat spiral, but after a while I got fed up fighting its attempts to kink into random shapes and let it take it's own course. For a more professional finish I'd cover the polystyrene with a piece of marine ply covered in foil and clip the hose to that as I went along. Live and learn .  Two 700m sheets of 4mm polycarbonate were screwed at 20cm intervals using these screws  Toolstation > Screws & Fixings > Decking & Roofing Screws > Plastic Corrugate Screw
Polycarbonate fixings are a ridiculous price .

A small hole was drilled through the wood for a thermistor to measure the temperature of the air space.

One hose leads from the drainage hole of the pool to a 12v Pump : DC 12V 550L/H Brushless Magnetic Submersible Water Pump Koi / Fish Pond Garden | eBay
This then pumps cool water into the heater matrix and the return flow goes to the pool.  I have weighted the end of the return flow after it got knocked out of the pool one day which emptied it .  The pump is powered by a cool box transformer that I had lying around similar to this: Campingaz / Coleman Euro Transformer 230V - Camping and Caravan Direct - Camping Equipment Suppliers, Outdoor Gear, Caravan Accessories
And the pump is switched on and off by a digital temperature controller like this : Digital STC-1000 All-Purpose Temperature Controller Thermostat Aquarium w/Sensor | eBay.  All housed in a weatherproof enclosure like this: Toolstation > Electrical > Exterior Wiring Accessories > IP 64 Weather Enclosure

Pictures to follow.

Ideally I would have a second thermistor monitoring pool temperature and shutting off the pump if the temperature in the pool was higher than in the heater but I haven't bothered yet.

IronGiant

Control box, still sporting its winter bubble wrap The thin blue pipe is protecting the thermister cable.
                                                                                                                                               

"heater": my arms aren't quite long enough to get a shot from above

                                                                                                                                       

SteveCritten

Sounds like a great job IG, just out of interest did you do any calculations to work out how fast the pump needs to go for optimum temp. What temp does it get the pool water at say a 24degree day?

True Romance

Thanks IG, looks like a cheap and easy way to heat your pool . As my pool is a bit bigger I've decided to look into a heat pump for next year. At around £700 (for the size I'd need) with savings of 50-60% on my current heating it should pay back in 2-3 years. Sods law we'll have another 8 years of crap British weather once I buy one

IronGiant

No, I haven't, I wouldn't know where to start   

I'll do some measurements tomorrow unless it's peeing down.  My feeling was if I throttle it down so that the water comes in at 50 deg C the sun will go down before enough water goes through to make a difference, so that in this sort of system getting all the water 6 degrees warmer is more efficient than getting a small amount of it hot. If anyone knows better please chip in

On a good day I can get the overall pool temp up by 6 degrees.  I need to get a night cover on it really to try and retain those gains because at the moment I'm losing a fair bit of heat overnight.

True Romance

A good solar cover will make a massive difference not only in retaining heat but also adding heat.

IronGiant

Thanks, I keep meaning to order one, I'll get on to it.