Help With Solar

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snapped

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Apr 20, 2008
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Hi I have been reading all fo the solar heating panel posts here for over a week but have several questions I hope someone can answer. I always like to get answers from people who have been there and done that to compare with the manufacturers .

1st My pool is a 13 x 29 ( almost grecian shape but not quite )fiberglass pool in Tulsa OK. It has no shade whatsover and I would like to extend the season as much as possible. In July and August my pool water avgs 88 degrees but the fringe months are tough for everyone but the kids( I swear they will swim in 50 degree water)

I have a Hayward 1 HP single speed pump with a Hayward sand filter that is rated for 44 GPM. I have 2 returns( the farthest is about 40 feet from the pump. The skimmer is about 25 feet from the pump, but I also have a valve to draw water from the bottom

I will be placing the panels on my roof and the section I have chosen is my 1 and 1/2 story roof that faces west ( which is the hottest direction here in OK) . This roof is about 18 feet wide, but over 30 feet tall with a 35 degree slope.

I really like the idea of the 20 ft fafco panels however their instructions say only the 12 ft and unde rpanels can be mounted vertically and that I must mount the 20 ft panels horizontally which wont work for me.

this will be a DIY project and I am good with PVC plumbing .

questions :

1. Does anyone else have 20 ft panels mounted vertically? Have you had any problems?

2. What is the differnce between AGP and IGP solar panels? I really like the solar bear panels but they are marked AGP.

3. Will I need to replace my pump to a larger size?

4. Black PVC pipe is extremely difficult to find has anyone tried painting white PVC pipe black?

5. I am planning on starting out with either 2 or 3 (4*20) panels. thoughts? the west facing sun here in OK gets brutally hot between 4PM and 8PM ( I will have direct sun on the panels between 11am and dusk)

6. Anything I forget please let me know. I have been searching for answers and find a lot of conflicting advice and ideas


Thanks
 
I am no expert but vertical mount just sounds wrong for these panels - they are intended to have the water go in the bottom (when horizontal) and out the top. There is no way you can build 2-3' bracing off one end to accomadate the layout?

I am not aware of the specific difference between the specs for AG and IG on these panels.

Hopefully someone with experience in vertical mounts can give some advice to help you out. Very interesting question!
 
Thanks for responding- so you think the panels shoudl be installed left to right(horizontal) and not up and down? Most 12 ft and below panels I see are installed up and down (vertical)

I keep seeing tips that the water should enter thru the bottom and raise to the top for maximum efficiency, however mounting them side to side seems to negate that efficiency.

Sorry if I am confusing anyone, but I am confused myself :?


Thanks
 
My assumption for the 20ft panels has always been that the either the weight of the filled panel or the hydraulics involved in such a long lift within the panel was the issue with vertical mounting. I imaging a 20ft panel could be made that would allow vertical mounting, but that the available panels aren't designed for it. With your roof, you have room for two rows of 12ft panels.
 
Although it can be done, there are a couple of problems with mounting vertically. First, as John pointed out the weight of the panels makes mounting on a vertical surface challenging. When they lay on the roof, less structure and mounting is required to keep them in place.

The water lift should not be a problem since an IG pump has enough head for this.

The biggest problem in my mind is that the sun's energy is hitting the panel at more of an angle. The effective area of the panel decreases as the sine of the angle of incidence where 90 degrees is maximum. This is much less of a problem with panels flat on the ground or on a slightly angled roof.

So if your latitude is 40 degrees N, at the sun's highest angle, it would be hitting the panels at 17 degrees incidence (73 off normal) which would result in about 30% of the effective area.

Winter is a little bit better with 63 degrees incidence or about 89% of the effective area.

Depending on your latitude, an angled roof is ideal to maximize the efficiency of the panel when you need it.

Here is a good reference for the effect.
 
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