Solar Would you do it again/Is it all that they advertise?

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QingGuy said:
@rick999 - unfortunately I'm about the least handy person you'll come across. 9 4x12 panels with all connectors, pipes, controller etc. is costing me $3,100 installed. Boy do I wish I was handy . . .


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Dont worry, there were times half way through it that I was wishing I spent the money. My Achilles heal is that I'm a cheap *** and grew up with a father a contractor. It is a fair amount of work especially when your up on the roof by yourself, its a bit ackward.

Botton line is that solar collectors are definitely worth it.
 
rick999 - apparently nobody told you that DIY coil solar heating doesn't work? :) That's what I've read and been told, time and time again. Glad to see that your system works good and does exactly what you want it to. Would love to see some pics.
 
Isaac-1 said:
Oh they work, but the commercial ones work MUCH better, this is coming from a been there and done that point of view
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How exactly do the commercial ones work better? I suppose the're are more efficient ones, but are they worth the cost if you can do it yourself, of course its got to be done properly, and while the materials are inexpensive, I don't deny it was a good deal of work especially doing the work on the roof. But I did this all on my own except for my wife helping me wind the second coil which is very difficult to do by yourself. Just AWKWARD!!! the first coil took me 4 hours to do on my own....very hard to stop from kinking. However with my wife to help on the second one, it took less than an hour to coil it.

I'm getting 30,000BTU out of my system and it cost less than 500$.

Of course I am not going to claim I know what the longevity is, but for me its sure doing the job right now. If I can get 3 years out of these without leaks I'll be happy. Keep in mind I dont have to worry about freezing where I am. Though I am wondering how they will stand up to 110 degree summers!

Here are the two "coils". This is 1000' of 1/2". I was getting a 4 - 5degree difference at 5GPM. However since this, I've added a zig zag of 300' of 1" PVC painted black. Now I'm getting 15 gallons per minute at 3 - 4 degree difference. Lower by one degree but that is not as important as the flow.

Kind of fun watching it start up at 10:30 am....temperature reading goes to 135 degrees then slowly comes down and settles 3 to 4 degrees above pool temp. On a slightly overcast day I get 2 - 3 degree difference, which is still quite amazing.

Not sure how this would work on the more northern regions but for my area its plenty. Been super rainy here the first part of the month, the pool was 74 degrees last Thursday and its 82 now, with no cover on at night. I loose a degree at night and gain 4 during the day. System runs from 10:30am to 4:30pm Nearly perfect clear sky conditions the past 4 days.

One coil is "second generation"...more "spokes" a lot easier to put it together that way. The hardest part is winding it on while the spool is unwinding. You have to continually "flip" it to untwist and prevent constant kinks. You

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really need two people to do this, very hard to do by yourself. The coil is 8 ' in diameter.

I feed the 2 coils with a 2" main line to the roof then breaking off feeding into a 3/4" then a reducer to the 1/2" coil pipe

I do have a small problem with the far coil not having the same output as the first one, I attribute that to it being higher on the roof and a further run of 3/4' pipe to it. Using a laser temp reader you can see a 10 degree difference between the two, so you know the water is moving slower on the higher one. I intend on fixing that by adjusting the position of the first one. Besides I made a booboo, and later discovered that the first one gets a shadow cast on it around 2pm from the second story roof DUH!!! Forgot to check that when I placed it.

The 1" pvc is fed from another valve opening with 1" painted PVC pipe running to the roof

The return plumbing is black 2" ABS ....lots of capacity for what I am running. From my research the black ABS was rated better for sun exposure. Wherever I used the white PVC I painted it with paint to protect it from UV.

I am returning it by a pipe coming over the side of the pool on my landscaping side with a 12" extension to direct the output under the water. Let me tell you it is quite a lot of flow at 15gpm. I tried to run it through the pipe where you would hook up the pool cleaner but it did not get the same outflow, thus I decided to go over the edge. For me this is really convenient where it comes down from the roof and does not look unsightly. Knowing this works now, I will disguise it with some landscaping rock and it will barely be noticeable.

In 6 hours Im getting about a 3 degree temperature change in the 8000 gallon pool.

I want to keep running this until I get up to around 88 degrees to give myself some buffer for cold rainy days. The last time it rained and was overcast I lost 3 degrees in one day!

Next step is to put electronic valve closer/openers to open and close the solar collector plumbing.
 
your right! but that is not a problem for me, rarely gets to freezing here and if we get a rare freeze warning, then I woudld just run water through them until it passes. But for northerners your right, you would have to blow them out really good or run anti freeze into them.
 
@rick999 First you claim you are getting 300,000 BTUs and then you claim to be getting 30,000 BTUs ... I am going to assume the first was a typo.

Solar heating is all about sqft of exposure to the sun and works more efficiently by heating a lot of water at a small 1-2 degree temp rise. Higher flow rates are better as the larger the temp differential, the more losses there are to the environment.

You have 1000' of 1/2" pipe ... that is generously 42 sqft (in your pictures looks like the tubes are smashed and overlapping). I will even give you credit for the 300' of 1" PVC which is another 25 sqft. So you have at best 67 sqft of exposure to the sun and if you are getting 30,000 BTU ... that is 447 BTU/sqft-day.

FYI, the commercial mats are are typically rated at least 900 BTU/sqft-day ...so, your setup is roughly 50% as efficient as the commercial mats.

You state to have $500 into your system of 67 sqft putting out 447 BTU/sqft-day giving you 30,000 BTU.

Looking at the inexpensive panels on Ebay, for $165 you can get a 4'x20' solar mat. But, you likely included some plumbing in your costs, so lets say this mat setup would be $250 to get up and running. For $250 you could have an 80 sqft panel setup that puts out 900 BTU/sqft-day for a total of 72,000 BTU.

So for 1/2 the price of your DIY setup, the commercial panel could be adding over 2x as much heat to the pool.

And THAT is exactly what we have been saying in this thread. Sure you can DIY a solar setup and it will certainly add heat to your pool and you can take pride in your creation, but you absolutely can NOT make it for less money and be as efficient as the commercially available panels.

I am happy your setup is providing you with the heat you desire, but I can not agree that a DIY setup is as "good" meaning amount of BTU per $ as the potential commercial panels.

FYI, I bought good Heliocol panels used on Craigslist and installed 500 sqft of heating myself for $1500, which includes all required plumbing, mounting, valves, and automation. New, my setup would have been around $5000 I expect. So for 3 times the cost of what you DIYed, I am getting around 15 times the amount of BTU added to my pool. This translates to earlier openings and later closings and not having to run the pump as long to maintain the desired temp.

Also, note, when I bought this house the previous owner had a DIY setup to the tune of 2500' of 3/4" black poly (granted it was not nicely coiled like yours). I was constantly battling it for leaks since it would not drain and water would get super-heated making the poly soft and kinking in the summer and in the winter, even here is Tucson, it would occasionally freeze and cause problems in the spring. I am MUCH happier with the setup I have now.
 
Jason, thanks for that detailed post and doing all the math. There are a couple of other issue I wish to comment on, first most people are limited by available roof space, which tends to lead to the round peg square hole problem with the DIY coils, even with creative stacking of multiple coils you still leave about 1/3 of your rooftop bare. Secondly that increased back pressure due to limited parallel water flow means you either limit water flow taking another hit on performance, or you are forced to use a larger pump which consumes more electricity.
 
I am getting 300,000 BTU out of this system. I was very careful in the calculations.

I left nothing to guesswork, I calculated exactly the GPM from the solar return. It was 15GPM. Using a digital thermometer very accurate, Temp of water from pool was 74. Temp after passing through the collectors and entering pool from solar collectors 78. That is a four degree change.

The calculations to determine BTU coincided perfectly with the temperature increase over a 6 hour period for an 8000 gallon pool thereby performing a cross check of the math.

If your doubtful still, I will look for my formula and inputs, I have it somewhere in a spreadsheet I put together.

Though some of the tubes look overlapping its a very small percentage, most lie flat.

More precisely ASIDE from the "infrastructure" the actual coils themselves were: 500' tubing $35 + wood framing $15 + misc 10$. Total cost per coil $60.00 Everything else is infrastructure costs to get water to and from the roof.....once done there is nearly zero cost to add additional coils.

I did try exactly what you were talking about the first go around. Not sure if it was the same brand but it was a 4'x20' collector fastened by straps every 4' and it promised 80,000BTU. The cost was $256 for the collector itself. Not only did it spring leaks the first 2 weeks I had it, but it nearly blew off the roof in a storm.

Again this was an experiment on my part.....I have a science background and from a contractor family so it was a natural fit especially since Im a cheapskate! it served its purpose, I proved to myself that solar is viable for what I want it for, and I will just add a small Nat Gas heater for the winter time to heat the pool from late Nov - Feb this coming fall.

Obviously this is not for everyone, but for a small investment, just about anyone who is handy can try it out for themselves to see what its like for a little bit of money. Not saying mine is better than the multi thousand dollar systems, but that anyone can do it no matter how small there budget is. My problem is when I go to spend $2000 on something, I ask myself...'could I save that money and buy another XXX shares of XXXX company for my retirement plan????" Often the answer is yes...and sometimes I regret it, and sometimes like this time it exceeds my expectations.

Glad I did it, when they fail, I will look at pro systems so long as it doesn't break the bank. Right now my hard earned money is gong into removing seven nasty 70' cypress trees which are a total SPOILER for this pool once we hit fall. Removal cost $6,000!!!!

I'm just saying to others, if you dont have a big budget you can do it too!
 
Sorry, there is absolutely no way you are getting 300,000 BTU in a day on 67 sqft. That would make your setup 4 time more efficient than the best commercial solar panels available.

Believe what you want, but there must be something wrong in your calculations. My guess is that the water is not being uniformly as one source of error.
 

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Measurements are uniform. I'll get my data and upload it when I get a chance. Never calculated BTUs before so unlike the Global warming crowd, I'm all ears to full "peer review".

If I'm wrong please show me where. If what you are saying is true....IM GOING TO PATENT IT!!!

In the end Im getting a 3 - 4 degree per day consistent rise in temp in the pool. I just checked it a second ago, and I'm up 3 degrees from this morning.

8000 gallon pool, how many BTUs would it take over a 6 hour period to raise the temp?

Also, wouldnt I be correct in saying that BTUs are also dependent on the solar exposure? ie....Im sure my BTU is much higher per sq foot here in New Orleans than it is right now in New York. Are you factoring that?

And what about the radiant energy from the roof itself. My roof at 10:30 am is 135 degrees.
 
Here is the Florida Solar Energy Center's data on pool solar water systems where they test the output of all the brands: Ratings Summary Page


I looked in the Heliocol PDF and it shows with inlet water temp at 86 degrees, the standard day output is 800 BTU/sqft-day. FYI at lower water inlet temps, that number is higher, which is why most panels state they are rated in the 900-1100 BTU/sqft-day.

This is a quote from one of their certificates about the standards:
Total solar energy available for the standard day is 5045 Watt-hour/m2 (1600 Btu/ft2) distributed over a 10 hour period.
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So at 100% efficiency, 1600 BTU/ft2 is possible in a given day (and like I said 900-1100 is typical of pool solar panels).

For your 67 sqft setup, at 100% efficiency in the Florida sun for 10 hours, you max out at 107k BTU/day.

It is not for me to say where your measurements or calculations are wrong, but, sorry to burst your patent dreams, 300k is just not possible. ;)

In your pool, it would take 8000*8.3*1 = 66.4k BTU to raise the temp by 1 degree. So if you thing you are uniformly heating 8k gallons of water by 4-5 degrees, I can see why you would think you are getting 300k BTU. But, physics states that is not possible.
 
Give me a day or two to put the numbers together. I'd like to know where I might have gone wrong.

But, if I am truly getting a 3 degree change in pool temp in a single day (I said 3 - 4 per day not 4 to 5...I think your referring to what I said I was getting for diff between the pool and collectors), isn't that by your calculations approx 180,000btu

Maybe that is the correct number and my memory is off from what I remember from the calcs....have a lot on my plate right now....could be my recollection was wrong from my formula. Would 180K btu be achievable? Because I am definately getting 3 degrees per day raise in pool temp.
 
If your system was as efficient as solar panels (which I KNOW is overly optimistic), then you could get 900 BTU/sqft-day.
67 sqft * 900 = 60k BTU/day which is about 1 degree in a 8k pool.
So there is a disconnect somewhere :D

Oh, one thing you are not taking into account is the heat that the sun is adding directly to the pool, unless ZERO sun is hitting the pool.
 
OK so I checked my numbers and I was off by a decimal point....you're right, 300,000 would be blistering!

The BTU calculation should be 30,000 btu per hour.

I have about 40% shade on the pool. Before I put the solar collector on I did not see any real change in pool temp from the sun, and with the solar cover I added about 1 degree per day but I hated that cover....cant see the beautiful pool and a pain in the you know what to remove and put back on especially since I have an irregular pool design.

What is fact is that I do get a 3 - 4 degree water temperature change between the input (water going up) and water coming back entering the pool at 15GPM. That gives you the 30,000 btu per hour.

This as I mentioned drastically changed the pool from cold to warm in a few days.

I was looking at some of the collectors that I had before and the one I purchased 4'x20' claimed 80,000BTU. But I dont know what that is...is that per day, per hour what? I can say however that it did not seem to have the output
that I have now. I'm sure the higher quality commercial ones will do much better.

In any event I am a happy camper and it cost next to nothing. When they fail, I'll look at commercial systems for a more professional look so long as I dont have to cover too much of the roof to get the same output. But at least now I know how early I can open up the pool and I expect that I can comfortably get into late November this year, leaving only a few months for a Nat Gas heater to kick in. I plan on putting an acrylic dome over the pool this winter, and adding 2 infra red heaters inside.
 
I love my solar system but I made a huge mistake when I installed them. I bought 12 fafco 4x20 panels off of ebay a few years ago and self installed. I used the included metal retaining straps like instructed but they ended up pinching most of the panels and created leaks in 4 of the 12 panels. I'm not a fan of the metal straps because the panels will sag as it expands and contracts over the straps, pinch the panels and create leaks. I should have gotten polyester straps instead. I ended up using straps on the larger plastic headers which won't pinch. Outside of that, I highly recommend solar.
 
Due to high winds and a personal event soalr hasn't been installed yet, scheduled for later this week.

Based on the fact that I don't use a cover and I'm not sure I want to (I have one still in the box) I'm wondering if I'm wasting my money as I won't see the full benefit of solar. Thoughts?
 

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