Solar Panel roof install

May 31, 2010
13
#1
I have been trying to find a good location to install my solar panels and the only spot that gets sun all day is the side of the roof which points north/east. I've read that I shouldn't bother doing the install for anything that doesn't point south or at least close to east/west. Does the fact that my roof is only a 4 pitch help offset the direction that its facing?


 

jblizzle

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May 19, 2010
41,197
Tucson, AZ
#2
The further the panels get from perpendicular to the sun's rays, the less efficient they are at heating ... putting on a nearly flat north slope will work just not as well.

Posted with Tapatalk ... sorry if I sound short ... hate typing on phone :)
 

jblizzle

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May 19, 2010
41,197
Tucson, AZ
#4
I do not know of any test. I do know that optimally, you want the panels toward the south at an angle close to your latitude. In Tucson, ideally it would be close to a slope of about 32 degrees.

Here is a blurb I just found online that sums it up:
To capture the maximum amount of solar radiation over a year, the solar array should be tilted at an angle approximately equal to a site's latitude, and facing within 15° of due south. To optimize winter performance, the solar array can be tilted 15° more than the latitude angle, and to optimize summer performance, 15° less than the latitude angle. At any given instant, the array will output maximum available power when pointed directly at the sun.
One option you have is adding a rack on the North side that brings the panels either flat or pointed toward the South.
Or put them out in the yard somewhere out of the shade (although less nice looking)

Are there trees that put shade on the South side of the house?
 

tphaggerty

LifeTime Supporter
Jun 27, 2007
218
Poughquag, NY
#5
My roof aims a bit more east than yours does (maybe ENE) and I have a relatively good pitch where my panels are installed. My roof gets about 8 hours of sun a day during most of summer, a bit less at either side. I compensated by adding panels, I have 8 1/2 on my 2nd story roof (the 1/2 is because I had to block out some of the panel to allow it to go around my radon vent) and 5 panels on my 1st story garage roof for a total of about 720 sq ft. In early spring, I can add 8 degrees or so a day (when the water is cold), so I can normally get my pool to the high 70s, low 80s by late May / early June (in New York). Depending on the weather (rain is really the only factor, cloudy days still produce heat), I have kept my pool open with the water into the low 70s into November. We have had the pool into the low 90s (sort of as a test). So, it can definitely be done.

And, just for good measure, I have about a 130 foot underground (uninsulated) pipe run from the pump pad to the house (and back). Not ideal, but it still works quite well!

I did the installation in 2 steps, so it cost me more than if I had done it all at once. I added the 5 garage panels, not to get more heat but to get quicker recovery when the pool gets cooled down (again, almost exclusively by rain). I put the panels on the back roof to hide them from the street, if I had to do it all over again, I probably would put them in the front and wouldn't have needed the garage panels. I have had 7 years of a wonderful, warm pool that stays open way past when everyone else in the neighborhood has closed for the season, all for about $7000 (and hopefully many more years without further investment, knock on wood).

I use a solar cover every night to retain heat (makes a huge difference for my pool).

If your main goal is to add heat during the "normal" season, I think you can get it done with no problem. If you are looking to extend your swimming season, that might be more problematic since your sun exposure only gets worse at the beginning and end of the season.

I agree that racking the panels to make them flat or pointing south would help, but in Tucson, I would think almost any direction would work!!
 

tphaggerty

LifeTime Supporter
Jun 27, 2007
218
Poughquag, NY
#6
I just noticed that you are planning on putting the panels on the SOUTH facing roof, if I'm looking at the picture and arrow correctly (my first take was that you were going to put them on the northern facing roof, at the top of your picture). If you are putting them on the southern facing roof, you have an almost ideal setup, flat roof or not!! You could rack them so they are somewhat tilted, but with the southern exposure, I'm not sure you would even need to do that.
 

jblizzle

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May 19, 2010
41,197
Tucson, AZ
#7
tphaggerty said:
I agree that racking the panels to make them flat or pointing south would help, but in Tucson, I would think almost any direction would work!!
The problem here is that you need the water almost in the 90s so it does not feel too cold :)

And even when it is over 100 degrees outside, when you get out of the pool and there is a breeze ... it is chilly since the evaporation works so well. Of course in about 2 minutes you are dry and hot and have to get back in the pool ;)
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
41,197
Tucson, AZ
#8
tphaggerty said:
I just noticed that you are planning on putting the panels on the SOUTH facing roof, if I'm looking at the picture and arrow correctly (my first take was that you were going to put them on the northern facing roof, at the top of your picture). If you are putting them on the southern facing roof, you have an almost ideal setup, flat roof or not!! You could rack them so they are somewhat tilted, but with the southern exposure, I'm not sure you would even need to do that.
Pretty sure the plan was the northern roof due to all the tree shadows on the south roof.
 
May 31, 2010
13
#10
I was also wondering about size piping for the pool. I have read some people using 1.5" and some using 2". I would like to switch everything over to PVC and if I do put the panels on the roof it will be about 70-80' to just get to the top of the roof with 30 - 35' of that run going up to the second story of the house. Would using 2" pipe help that?
 

linen

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Jul 30, 2010
8,649
Twin Cities, MN
#14
Cast0077 said:
Even for the runs from skimmer to pump and return to pool ?
Yes, espeically from the skimmer to the pump.

tphaggerty said:
I'm all 2" pipe as well. If you do that, make sure your panels have 2" headers, otherwise it doesn't make a whole lot of sense to do 2" in the rest.
Even if the headers are smaller, especially with long runs you would still benefit from 2" pipe.