Become a TFP Supporter Welcome to our new server and new forum software. Pool School
Results 1 to 9 of 9

Thread: Home made solar question

  1. #1
    Senior Member solarboy's Avatar
    Join Date
    Aug 2010
    Location
    Europe
    Posts
    338

    Home made solar question

    I'm almost finished building a home made solar collector. It is basically an oval lozenge shape on top of a poolside pergola. I've divided up the 2" feed into 20 x 5/8" irrigation pipes that spiral round 4 times before being "collected" together into a 2" pipe together. The spirals range in total length from 130' to 200'. The total collector area is 172sq.feet. The pool surface area is 193sq.feet. This is just under 90% of the pool surface. I understand that it would have been consistent to have had all the pipes the same length.
    I have a huge sand filter and currently my pressure there is 12psi with DE (Pool has 1 skimmer,1 main drain and 2 returns)
    My question is, I'm reasonably sure with the extra strength of the irrigation unions/clamp brackets/pipe I can run my currently 37 GPM all through the collector without any bypass to get a much higher efficiency than normal. Will the plumbing take this throughput without issue ?

    As a side note, it has been said that this type of home made solar isn't worth the effort is it's cheaper to buy retail collectors. These cost me around $2.80/sq.foot and I was able to fit 9 square feet per hour for a total of 20 hours.
    Attached Images Attached Images
    Self built 5500 gallon bare concrete (temporarily) pool with limestone coping, Pentair Swimmey 1/2 HP pump, Triton sand filter with DE, Simpool peristaltic muriatic acid pump with pH sensor and Monarch SWG. Home made solar heater with Pentair Compool control panel and 3 way valve. 1 skimmer, 1 main drain, 2 returns, 2" plumbing, Hayward auto fill valve.

  2. #2

    Re: Home made solar question

    Love the picture they always help one see what is going on. Can't help much with the questions but have one of my own.

    Have you calculated/thought about how much weight in water you will have on top of your Pergola? Can't see what the underside looks like in the pictures.
    Pool #1 IG 24k Diamond Brite plaster with spill-over spa. Jandy Aqua Link RS One Touch with built into pool floor cleaner. Jacuzzi Magnum pump/basket feeding Hayward top mount Zeosand filter. Jacuzzi Magnum pump/basket for Spa Jets. Heat Siphon pool heat pump. Dolphin Robotic pool cleaner.

    Pool #2 IG 35K 20X40 Vinyl. Hayward top mount Zeosand filter with Pentair 3 HP IntelliFlo VS+SVRS. Chemical Free pool using Water Doctor Copper Ion Generator, PoolSkim, Polaris 9300 Sport robotic pool cleaner, Heat Siphon pool heat pump, solar blanket, Ameri-Dome 50X30 dome enclosure during Winter.

  3. #3
    Senior Member solarboy's Avatar
    Join Date
    Aug 2010
    Location
    Europe
    Posts
    338

    Re: Home made solar question

    Thanks for the reply. The weight is 127lbs which isn't a problem as there are 5x3 joists on 24" centres underneath.
    Self built 5500 gallon bare concrete (temporarily) pool with limestone coping, Pentair Swimmey 1/2 HP pump, Triton sand filter with DE, Simpool peristaltic muriatic acid pump with pH sensor and Monarch SWG. Home made solar heater with Pentair Compool control panel and 3 way valve. 1 skimmer, 1 main drain, 2 returns, 2" plumbing, Hayward auto fill valve.

  4. #4
    Administrator JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    34,659

    Re: Home made solar question

    You should be fine at that flow rate as long as all your joints are good.

    Commercial panels on eBay seem to go for around $2/square foot in the US. I also suspect that they would be about twice as efficient as your setup, though that is just a rough estimate. None the less, you should get a significant amount of heat out of your rig.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  5. #5
    Senior Member solarboy's Avatar
    Join Date
    Aug 2010
    Location
    Europe
    Posts
    338

    Re: Home made solar question

    Thanks for that Jason. I'll be tightening those pipe clips a little bit extra. I think in Europe the panels must be overpriced, the retail price of quality panels is $9.50 ! The eBay ones are about $5.70. I'll be taking extensive measurements when they're up and running so I can get an idea of the inefficiencies.
    Self built 5500 gallon bare concrete (temporarily) pool with limestone coping, Pentair Swimmey 1/2 HP pump, Triton sand filter with DE, Simpool peristaltic muriatic acid pump with pH sensor and Monarch SWG. Home made solar heater with Pentair Compool control panel and 3 way valve. 1 skimmer, 1 main drain, 2 returns, 2" plumbing, Hayward auto fill valve.

  6. #6
    Senior Member
    Join Date
    Jul 2010
    Location
    Pt. Arthur, TX
    Posts
    163

    Re: Home made solar question

    Too cool.

    You guys are just way too cool.
    Custom Cloud shaped 19'x35' - Raised Spa 6' diameter
    Rainbow 320 Inline Chlorinator - Paramount Clear O3 Ozone Generator
    Hayward C4025 Cartridge Filter (Hayward CX880XRE) - Hayward Tristar 2 speed pump
    Hayward H400Fdn Heater, Hayward GVA-24 (valve actuators)

  7. #7
    Senior Member
    Join Date
    Mar 2009
    Location
    Huntsville, AL
    Posts
    156

    Re: Home made solar question

    Would it be a problem if the weight was between 550 and 700 lbs (or more)? My math, or assumptions, might be wrong but I think 127 lbs is on the low side.

    In round, easy to work with numbers you have 20 tubing loops of 150 feet (first assumption) for a total length of 3000 feet of tubing.
    If (2nd assumption) the tubing weight is 10 lbs per 100' it the weight is 300 lbs, if it is 15 lbs per 100' it is 450 lbs.

    If the inside diameter of the pipe is 1/2" (3rd assumption), the area is about 0.2". Multiply that area by the tubing length in inches and dividing by 231 gives you U.S. gallons. One U.S. gallon of water weights about 8.3 lbs. So 0.2 x (3000 x 12)/231 = 31.1 gallons *8.3 lbs/gal = 259 lbs (of water). Or about 250 lbs, to make it an easy number to work with.

    So that is how I came up with a combined weight of 550 to 700 lbs. I don't know the exact specs or length of the hose that you used, or what weight your pergola can carry, but I did want to let you know that I think your weight estimate is on the low side.

    I also want to say what a great idea it is! My wife saw the picture and is already thinking that she might want me to do something similar.

    Good luck with your project!
    Gordon
    27K gal, IG vinyl, 1.5 HP pump, 24" sand filter, Goldline Aqua Plus SWG

  8. #8
    Senior Member solarboy's Avatar
    Join Date
    Aug 2010
    Location
    Europe
    Posts
    338

    Re: Home made solar question

    You're right, it is more than I thought. I had to do it in metric and I got..
    6.5mm pipe radius at 1000m gives a volume of 132 liters or 291 lbs. Your estimate is amazingly close considering. The pipe itself weighs (very approximately) 110 lbs so probably a combined weight around 400 lbs. The joists spacing and size are the same as our house roof which was engineer calculated to carry 40kg of tiles per square meter which works out at 936 kg (2000 lbs) over the whole (258 square feet) pergola.
    Thanks for your input Gordon, it always makes me feel more confident to know someone else has also pondered.
    My granddad always said, "measure twice, cut once".
    Self built 5500 gallon bare concrete (temporarily) pool with limestone coping, Pentair Swimmey 1/2 HP pump, Triton sand filter with DE, Simpool peristaltic muriatic acid pump with pH sensor and Monarch SWG. Home made solar heater with Pentair Compool control panel and 3 way valve. 1 skimmer, 1 main drain, 2 returns, 2" plumbing, Hayward auto fill valve.

  9. #9
    Senior Member solarboy's Avatar
    Join Date
    Aug 2010
    Location
    Europe
    Posts
    338

    Re: Home made solar question

    Well I got bored of doing spirals and connected it all to the pump with only half the eventual pipe "just to see". I connected the 1/2" pipe to the manifolds with irrigation barbed angled connectors with hose clips but they leaked like crazy so I swapped them for 3 part pipe connectors (rubber o-ring,split clamping ring and pipe "nut") and the leaking stopped. In 3 days my end of day temperature has gone up from 73F to 80F while max. daytime temp has dropped 2 so it's obviously working. You can feel the heat at the returns so I'm a very happy bunny. Swimming is balmy ! Only 10 more spirals to go and then I'll post some detailed numbers and hopefully work out the efficiency compared to commercial panels.
    Self built 5500 gallon bare concrete (temporarily) pool with limestone coping, Pentair Swimmey 1/2 HP pump, Triton sand filter with DE, Simpool peristaltic muriatic acid pump with pH sensor and Monarch SWG. Home made solar heater with Pentair Compool control panel and 3 way valve. 1 skimmer, 1 main drain, 2 returns, 2" plumbing, Hayward auto fill valve.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •