new diy solar water heating project for above ground pool - advice please?

[Mike90250]

you have to look at the pump specs, flow & head.

[barnsley]

you have to look at the pump specs, flow & head.

thanks I found a .75 hp pool pump with 8.5m max head. So that should do the trick.

I probably had low flow because of back pressure from going from 32mm to 13mm pipes.
Maybe I should have tried using just the same size hosing throughout, but I thought it would be cheaper and more efficient to use smaller hosing.
I just hope that any back pressure created from reducing pipe sizes can't damage the pump..?

[Logan5]

you should probably plan this using a manifold, restricting water flow is not good for pumping energy efficiency, a manifold will allow you to split the large hose into smaller tubing for radiant collection, another manifold at the other end to combine back to common size pipe.

[barnsley]

you should probably plan this using a manifold, restricting water flow is not good for pumping energy efficiency, a manifold will allow you to split the large hose into smaller tubing for radiant collection, another manifold at the other end to combine back to common size pipe.

do you mean use something like a bypass valve into another pipe? And could this just go straight back into the pool?

[barnsley]

Maybe I could use a regular 32mm hose pipe splitter?
(- with a 20mm off shoot and my 13mm solar hose contraption) or would that just send most of the water down the path of least resistance?

[Logan5]

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something like this, I have also worked with brass models

[Logan5]

This is a good solar project, but unless you take your time, study fluid and thermodynamics, already posses some understanding of engineering and build planning, you are going to waste a lot of money and make a mess of your yard.

[barnsley]

Thanks. I could understand that for a bigger and better pool but this is just a 12ft (3.6m) above ground pool which is just seasonal. But yes I should learn more and I'm trying to

[Logan5]

yes that particular manifold may be a lil large, but it is similar to what you need to prevent wasted energy due to restricted water flow.

[barnsley]

What's the difference between a manifold and a t connector? As long as it adds up to the same width as the input?
Like 20mm & 12mm outlets from 32mm pool pipe

[Logan5]

pl10439200-2_street_x_2_slip_x_4_3_4_barb_style_plastic_water_manifold_for_home_spas.jpg maybe this.

[barnsley]

i think these manifolds are not readily available in the UK.
when i search on ebay - it just returns US results. But we do have available splitters like this:

http://www.ebay.co.uk/itm/380870719730?_trksid=p2057872.m2749.l2648&var=650228227640&ssPageName=STRK%3AMEBIDX%3AIT

and 3 way flow taps like this:

http://www.ebay.co.uk/itm/3-Way-Flow-Tap-Regulator-Flexi-Hose-Pipe-Control-Valve-Adjuster-Pond-Fitting-/191911006994?var=&hash=item2caec99312:m:mNCATqX2_elXbokrqth3s0A

Same idea in principle (so i suppose i could use something like these)

[barnsley]

I know I could have done things differently, such as the hose material;
I used PVC hose (oops), but in the UK rubber hose is 3 times more expensive and would have cost me almost £100 for 100 feet (30m) that's well over $100.
I did a test today, and ran the solar system with 2 hoses in parallel and it actually seems to flow nicely - not too fast to be useless and and not too slow to be a major proble to the pump (I hope). - This was on the ground though, and not on the shed roof where I'd like it to be, so I think I'll still upgrade my pump to a 800w Clarke's one with 60PSI and 40m max head:

http://www.ebay.co.uk/itm/252456666463?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I could just use the upgraded pump on sunny days and my old less powerful pump at night, on cloudy days and when pool is not going to be used (as it would be more efficient then).