Pool Solar Finished

[boston62]

That's a pool solar panel. We just call them solar panels. Not to be confused with photovoltaic solar panels. The fafco ones like you got usually run $160-190 each, so you bought $1800+ worth of panels for $50. We all kinda hate you right now. Well, we're envious anyway.


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I did have a few with one leak in them but simple plugging them..I had to rent a U haul truck to pick them up, that was a 100.00....The do work great, free heat.

 

[boston62]

I got mine used off of Craigslist.

Got mine there also.

 

[boston62]

I am trying to get my GPM down when running my solar, it's running at 50 gpm @ 2500 rpm, if I drop the speed down then I have to much air in the return when running. I did clean the filter. The panels are about 30 feet to the top of panels. Any ideas. The VRV is in the bottom. I have 7 4 x 10 panels. Thanks

 

[jblizzle]

If you are getting air (assuming it is not in the pump from the suction side), then likely the pressure is too low at the VRV. You would have to either lower the VRV or increase the speed.

You know that solar heating is most efficient at higher flow rate right?

 

[boston62]

No its not in the pump suction side, I have a jandy check valve on the return from solar, the check valve I put after the filter, I installed a FloVis, this where I have it. The only way air can enter solar is through the VRV, a panel leak would just squirt water, or would it suckered air also? Thanks

 

[boston62]

Where can I find solar panels for $50 a pop!?

Just saw 7 4 x 12 Fafco with hardware
$150.00 on Craigslist.

 

[tlevy]

If you are getting air (assuming it is not in the pump from the suction side), then likely the pressure is too low at the VRV. You would have to either lower the VRV or increase the speed.

You know that solar heating is most efficient at higher flow rate right?

Really? That is somewhat counter intuitive, since I would have assumed that lower flow would mean more time in the tubes, and more contact with the suns heat. Can you expand on that pls? Solar heating is definitely in my future for our pool....

Thanks!
Tom


90,000litre, IG vinyl, 1/2 HP Tristar pump, Sandfilter, Aquarite T-15 ASG

 

[tommyd123]

Somebody with more knowledge on the subject will come and provide a better answer than me, but this is the basic idea: Water absorbs heat more efficiently when the temperature differential is greatest. You are not just heating the water in the tubes, you are heating the whole pool.

 

[jblizzle]

You get more heat added to the pool by heating a lot of water a few degrees than by heating a little water more degrees.

In the extreme, if flow was very slow, you can imagine that the water heats up a lot and the pipes would feel warm. Well, if you can feel the pipe is warm, then you are losing heat back to the air. The solar panels should be cool to the touch indicating all the heat is transferred to the water.

 

[tlevy]

Thanks! That makes perfect sense. Presumably there is an "optimum" flow - not too fast, not too slow.


90,000litre, IG vinyl, 1/2 HP Tristar pump, Sandfilter, Aquarite T-15 ASG

 

[jblizzle]

Not really. The higher the flow rate the more heat to the pool. But, there is a pretty severe diminishing of returns. Most panels recommend around 1gpm per 10sqft of panel area.

 

[boston62]

Is the flow rate the same at the panels 25 ft up, as it would be right after the filter?

 

[jblizzle]

It has to be if all the flow is diverted to the solar.

 

[Isaac-1]

Flow rate will be the same 25 feet above the pump, but pressure will be about 10 psi lower (14.7 psi for every 34 feet of water column, you can do the exact math if you want), If pressure at the panel is below 0 then you will get a suction (siphon effect from the down spout) and suck air in through the Vacuum breaker valve. Remember this is pressure after your filter, your regular pressure gauge measures pressure before the filter.

 

[boston62]

Thanks everyone, that clears it up.

 

[boston62]

Is it possible to not have enough volume of water to feed the solar panels, I have just my skimmer open, but it seems if I open my main drain, the solar seems to run better. Thanks

 

[jblizzle]

Lower suction head by opening the floor also will certainly increase flow rate.

 

[Agent99]

I am trying to get my GPM down when running my solar, it's running at 50 gpm @ 2500 rpm, if I drop the speed down then I have to much air in the return when running. I did clean the filter. The panels are about 30 feet to the top of panels. Any ideas. The VRV is in the bottom. I have 7 4 x 10 panels. Thanks

You and I are in the same boat. I tried running at 2000 rpm and my returns got very noisy and had small bubbles coming out. As I slowly raised the rpm, the bubbles became fewer and fewer and the returns got quieter and quieter. I run mine at 2400-2500 rpm. My flow is around 60 (Flo-Vis) although I didn't pay attention to it as I played with the speed. One of these days I'm going to plot out a chart of GPM/Pressure/RPM/Watts with and without the solar on.

 

[boston62]

I installed a FloVis in after the filter, and that says 2 " at 70 gpm. I thinking of installing a shut off valve on the solar return, and try closing it a little and see if it keeps the panels full, at a slower speed.

 

[Agent99]

I look at it this way: It is much slower than my single-speed pump! I may never break even by electricity savings on this spendy pump but it is cool as all get-out being to vary the speed. Our local utility here helped by kicking back a c-note rebate so that helped some. In winter when I 'close' the pool, I can run it (solar off) at around 1500 rpm just a couple hours a day so I'll get some benefit then.

My FloVis is at the same spot: right after my filter.