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Homemade solar pool heating system with black pipe
By thebbqguy, Section Homebrewed Electricity Posted on Sun Aug 10, 2003 at 08:51:50 AM MST
Just thought I would post info about my solar system in case anyone is interested.

Hi all,
Just thought I would post info about my solar system in case anyone is interested.
http://www.powershotgraphics.com/pool
I currently have 3 separate systems running for my 18 foot above ground pool. The pool is 52" high and is has a lot of water, - don't know,
but somebody told me it holds 28,000 liters ( I live in Canada )
I know that 1 U.S. gallon = 3.8 liters.
anyway I have 3 systems, .... started out with one, but realized it would never work ...... as there's just too much water to heat up.
The first system I used black utility hose, - 1/2 " and have 500 feet of it. That worked so well, that I made another system and put that
on the roof of my child's play structure outside .... that one has 400 feet.
Then this past week I bought another 600 feet of black hose and now have that running as my 3rd solar system.
All system are 100 % independant of each other, and all are running off the 1.5 hp motor that came with my pool, there's no strain on the
motor by the way, which is great.
I push 8 liters of water every minute from each little 1/2 hose - and water is about 88-89 degrees, once the water has been running about a good 15 minutes.... when it first starts water is about 127 degrees F.
anyway let me do some math here:
8 liters of water from each hose per minute.
That's 24 liters total from the 3 black hoses per minute.
there are 3.8 liters in 1 U.S. gallon.... so.....
24 divided by 3.8 = 6.3 gallons per minute.
so, 6.3 gallons x 60 minutes = a total of : 378 gallons per hour .
That's enough to fight the battle..... the first 500 feet of tube I had installed - only one pipe - was beautiful, but I quickly realized that this
was just not enough to fight the pool, - when you have that much water in a pool it's just not doing much if not anything.
From what i have read, - if a solar heater is big enough for your pool, you should be getting about a 2 degree per hour rise - from the solar
heater alone, and another 1 degree per hour from the sun with its passive heating, -so that's 3 degrees per hour increase which is amazing.
anyway you can check out my images at : http://www.powershotgraphics.com/pool

Homemade solar pool heating system with black pipe | 12 comments (12 topical)

Temp of static water in solar exposed Black Pipe? (3.00 / 0) (#12)
by captainwiks on Fri Jun 05, 2009 at 01:07:28 AM MST

I am trying to make a very simple solar hot water system for a off the grid home in Honduras. I was simply just going to coil 1 1/2" black irrigation pipe on on the galvanized roof and feed it off the gravity tank into the hot water line of the house. My question is....Does anyone have any idea how hot the static water in the solar exposed pipe might get? Cpvc pipe (rated to 210 degrees) is not readily available in Honduras and pvc is only rated to 140 degrees. It rarely gets over 95 degrees, but can get pretty hot on the metal roof. I have only been able to find pvc connections to go from the black irrigation pipe into the house plumbing and I am wondering if it might get too hot........appreciate any input.

Re: Homemade solar pool heating system with black (none / 0) (#1)
by wooferhound on Sun Aug 10, 2003 at 09:33:16 AM MST

The temprature rise of 2 degrees an HOUR seems a bit too high. I'm pretty sure that if you are getting a 2 degree rise in a DAY that you would be fine. My Solar pool heater was getting a 1 degree rise per day which I thought was perfect.

Where are you getting your Black Tubing and what type of stuff is it (flexable / stiff).
W o o f -={(
Huntsville Alabama U.S.A.

Re: Homemade solar pool heating system (none / 0) (#2)
by drdongle on Sun Aug 10, 2003 at 10:41:27 AM MST

System looks great!

Dr.D
Carpe Vigor, Dr.D

Re: Homemade solar pool heating system (none / 0) (#3)
by sean on Sun Aug 10, 2003 at 04:54:27 PM MST

looks great but if it was under glass it should work even better and for more months of the year..........sean

[ Parent ]

Re: Homemade solar pool heating system (none / 0) (#4)
by thebbqguy on Mon Aug 11, 2003 at 07:06:46 AM MST

Hi Sean,

Thanks for the info about the glass. I will go price plexiglass for fun,
but a sheet of 4x8 sheet is over a $100 here in Canada.... I bought a small
section about 2 years ago for a coffee table - about 3 feet x 2 feet and it was $55.xx if memory serves me correctly.

Morning Tim,

With the professional solar collectors, you should be getting way higher temps than with homemade systems, I have read numerous posts that a system can lift your pool temp by a good 6 - 8 degrees in a day. -- This is totally normal, * if * your solar system is 100% that of the area of your pool.

My 18 foot above ground pool has 254 sq feet of area. In order for me to have
100% of that area, can you image how many 4x8 sheets of piping I would need to equal that area ? - my lawn would be full of sheets ( yikes ) !

My 4x8 sheet is not even totally full of pipe..... the middle of the sheet is empty because the black piping is not that pliable and started to kink when I got too tight of a circle in the inner part.....

Anyway in theory that 4x8 sheet of plywood = 32 sq feet ONLY !

My brother has a math "template" to figure out from the size of tube and the length of tube to tell you pretty bang on how much sq footage total you have in a certain length of pipe.

I originally started off my solar system with only one pipe running into the pool,
I had 500 feet of pipe ( 1/2" ) running on this system.

Anyway eventhough the temp was coming out rather nicely - about 89 degrees, - I quickly realized that there was just not enough flow for the temp to rise that much.

I then added another solar piping system, - installing it on my children's play structure roof... this one has 400 feet of pipe on it.

I then thought, ok if 1 is borderline, 2 must be better, so how about adding in another ? ... so I went out and bought another 600 feet of black pipe and have that just spread out over black roofing paper on the patio right now.
- heat coming off this 600 feet of pipe, eventhough not tacked down and evenly spread out so sun hits 100% of it, is quite amazing, temps coming out of it are really nice - about around that 88-89 degree mark - running at 2 liters per 15 seconds.... - that's 8 liters per minute.... ( 1 U.S. gallon = 3.8 liters )

anyway when I turn on those systems at the beginning the water coming out is naturally very hot - so hot you can almost scald yourself.

I know that even with 3 solar water tubes running into my pool, the sq footage that is coming out of my 3 systems is just not anywhere near what should be... in order for my pool to get a 3-4 degree temp increase per hour, I would need 20 of those tubes running into the pool - each running on an independant system... ( all my systems are NOT connected to the other systems) each is 100% independant of the other.

I did try running 2 solar systems together as one - meaning I connected the 500 feet of tubing on the 4x8 sheet, and the 400 feet on the children's play structure roof.... just connecting the tubes together.....

I noticed that the water temp was indeed higher, but the flow was not..... and from what i read, it's temp, but ALSO flow that makes a good system..... if flow is too low, then you don't achieve much..... so I broke them into 2, and get a much better heating system from that.... - a guy from one of the professional solar collector companies actually told me to do this, but I won't mention names.

Tim, that hose - it was $9.99 for 100 feet.... they also sell it in 400 foot lengths, - that was #39.99 ..... I bought it at my local hardware store.... the guy told me they use it for drainage at cottages and is a standard tubing that is found all over the place. - they use it in grocery stores also for certain parts of the plumbing.

Anyway the first 400 feet of it I bought , I bought 100psi rated tube, which was $10 more for the roll... so that was $49.99 .... but when I went back to get more, they only have the piping at 75psi, so I bought that, - it was cheaper, and I just don't see the need for the extra 25psi.... - if they had it, I would have bought it, but none was in stock.

The pipe is pretty pliable, but NOT as pliable as garden hose, but it is indeed pliable enough to work with totally fine.

anyway sorry if I went on like a broken record.

If you look at the professional solar collectors, you will see that they use huge piping that goes to and from the actual solar collector ( panel ) that sits on your roof for example.... each collector can push out a good 2-4 gallons per minute ! - so imagine when you have 8 of those collectors on your roof !

* good example *

My brother lives in Vancouver - they get a lot of rain there, and weather is nowhere near what it is like here in Ottawa ( we get much hotter summers)
he went to a friend's house about 2 weeks ago....... my brother said the guy's pool was 94 degrees !!!

How was this possible ? ... well when the guy bought the house, it came with the pool and a professional solar collector system - the roof is full of collectors, and the piping going to the pool pump motor is the standard 1-1/2 or 1-1/4 inch size..... anyway the guy told my brother that he has to turn the solar system off all the time because the pool gets too hot ! - anyway that day his wife had left the system on, and so the water was way too hot to be refreshing.

* I wish I had those problems :-) *

Anyway that goes to show you the power of solar collectors, if they equal the sq footage of your pool - you can get amazing water temps. - I've read some of the really high quality collectors available boast a temp increase in your pool of 10 degrees - provided you have 100% coverage in sq footage on your collector.

Right now I guess I have what... about 1/6th coverage in sq.footage, so I am nowhere near what i should be.

If I lived further out in town, had a large property, I would buy 10 sheets of 4x8 plywood, and coil 400 feet of black tubing on each one .... now imagine the solar energy that would come off something like that - wowie !

Mark.
http://www.powershotgraphics.com/pool

I'll take some new pictures today of the connections to my pump, as the website at this moment doesn't reflect the 3 seperate connections for each of my existing solar systems.... - I have installed "y" tubes onto the pool filter system, right near the pool, and each of the "y" connectors attaches to a black 1/2 tube ( the solar tubes) ... and each "Y" has a valve to turn off each and any of the tubes at any time.

[ Parent ]

Re: Homemade solar pool heating system with black (none / 0) (#5)
by wooferhound on Mon Aug 11, 2003 at 08:01:27 AM MST

The pipe is so small and it is so long. Pipe has resistance to water flow. This resistance is called `Head' and is measured in feet, as if the water were being pumped uphill for that number of feet which loads the pump down. Here is a link to a chart showing the friction Head for all pipe sizes and flow rates.

http://pump.net/frictiondata/fricofwater.htm

they don't list PVC pipe so scroll down the page and select 1/2 copper pipe then find your flow rate on the chart and you'll see the resistance to the water in feet. Also any fittings in the system (like 90 degree elboes) has head resistance. The chart for pipe fitting head resistance is at the top of the page linked to above.

..............................

The pool heater I built was raising the temprature of the water by about 1.7 degrees as I measured the difference between the pool water and the return water from the heater. Plus the temprature of my 2500 gallon pool was rising by about 1 degree per day. unfortunatly my pool developed a leak and drained itself, but before that happened we were swimming in 88 degree water, up from 76 degrees on the day I got it operational. We are planning to try and return the pool to Wal-Mart for replacement.
-
W o o f -={(
Huntsville Alabama U.S.A.

Hmmm (none / 0) (#6)
by Demetri on Mon Aug 11, 2003 at 11:28:52 AM MST

I know this would be an absolutely HUGE pain in the butt, you'd never drain your pool specifically for this(Geez, what would you do with all that water? And your water bill from refilling it? Assuming you don't have a well.), but if you ever have your pool drained sometime, you might consider painting the bottom of it black. Or maybe a cool picture in predominantly dark shades.

Demetri
Uncommon sense required.

Re: Hmmm (none / 0) (#8)
by wooferhound on Mon Aug 11, 2003 at 03:34:56 PM MST

The problem with a pool painted a dark color for heat is
that you can't turn it off if it gets too hot . . .

W o o f -={(
Huntsville Alabama U.S.A.

[ Parent ]

Re: (none / 0) (#7)
by thebbqguy on Mon Aug 11, 2003 at 11:45:32 AM MST

Hi Demitri,

I'm super lucky, where I live in Canada, - we have no water meter,
so you use as much water as you wish, and that's the end of story.

Lucky we live where there's never a shortage. We have so much water we sell it to many of the upper States in the U.S.A.

As for draining, it's as easy as pie, you just run your drain hose, which is a flexible baby blue hose out to the street and let it go, there are sewers in front of every house, so that's quite convienent.

Mark
http://www.powershotgraphics.com/pool

Re: Homemade solar pool heating (none / 0) (#9)
by Electric Ed on Mon Aug 11, 2003 at 08:08:53 PM MST

It is nice to see people making use of all that "free" solar energy.

However, I believe that for heating a large volume of water to a relatively low temperature, such as for pool heating, a collector with more parallel branches would be more efficient.

You described three "branches" of 400 ft, 500 ft, and 600 ft, using a total of 1500 ft of pipe.

I would recommend, say, fifteen branches of 100 ft each instead. Of course, the down side is that this involves more plumbing, and you would also need a higher volume pump.

There is a maximum water temperature that can be achieved with the pipe exposed to the air.
The problem with the longer run is, if the water gets up to that maximum temperature in the first 100 ft of the run, the remainder of the pipe in that run is wasted.

Electric Ed

Re: Homemade solar pool heating (none / 0) (#10)
by thebbqguy on Tue Aug 12, 2003 at 07:51:01 AM MST

Hi Ed,

Wow, well you bring up a good point.

I'm going to do a test today and try using a 100 foot piece of tubing
and take the temp of water flowing from it, once it has been flowing for about 10 mins.

The other day, I had a 400 piece of tubing running at 8 liters per minute,
the water was warm.

I stopped the flow, added on 2 other lengths of 100 foot tube, so I now
had 600 feet of tubing.

I turned the flow back on, and let it go for a good 5 minutes, and then checked the water temp - .... it was MUCH warmer than it was with the 400 feet.

This told me the longer the length the better ..... but you are right, there must be a happy medium.

I'm thinking of doing this, if your thoughts are correct about the tubes

I'll take a 1-1/2" black pipe ( used for bathrooms) ... the same size my pool filter is running on......

I'll take that tub, and cap one end of it, - the other end will be hooked up to the pool filter.

Ok now I want to drill holes all the way along the pipe and slide my existing 1/2" pipe into those holes and have each length of pipe say a length of 100 feet like you suggest.

I don't know, would it be more effecient ? ... I don't know how to attach the small 1/2" pipe into the larger pipe, maybe just PVC glue would do it.

Anyway, don't know if this would be more effecient, but would be a fun project.

Mark.
http://www.powershotgraphics.com

[ Parent ]

Re: Homemade solar pool heating (none / 0) (#11)
by Coolluke on Sun Feb 22, 2004 at 07:15:18 PM MST

Hi I came across this thread about a month ago and found it quite interesting, and thought I would put my design out there and see if anyone has comments, or suggestions. http://www3.telus.net/teeoff/solar

[ Parent ]

Homemade solar pool heating system with black pipe | 12 comments (12 topical)

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