Solar heat panel mounting

[divinduck]

I have a garage next to my pool that has an east/west sloping roof , do I mount solar heater panels on the east side for morning sun or the west for afternoon sun ?

 

[JasonLion]

Ideally you want to mount panels on both sides. If you are only doing one side, then think about possible shading from trees (bad) and check if either one points slightly more towards the south (good) than the other. And of course, would panels be unsightly on one side or the other?

 

[divinduck]

Thanks Jason, no trees, and building is dead due east/west. I was going with 1 4x20 but now I may go with 2 one on each side of the peak.

Also, my pool is an AG but piped with 2" PVC,do the Fafco panels have 2" headers ? as I don't want any loss by smaller pipe

 

[JasonLion]

If you are only using one or two panels the size of the headers makes no measurable difference. The maximum flow rate per panel is limited, so 1 1/2" is fine till you get up to several panels. There is only a tiny restriction in flow from having to step down to 1 1/2" pipe for a few feet. The longer the length of the 1 1/2" section of pipe the more important it becomes.

 

[divinduck]

Thanks for the reply, I am in New Orleans and want to start my swim season early, would 1 4x20 surfice or do I need 2 also my pump is 1hp 2 speed, will the low speed work with the panels mounted 14' high ?

And I still havn't decided on east or west slope

 

[Bama Rambler]

My opinion is that you need at least two of the 4x20 panels.

I think you'll just have to try the pump on low to see if it'll push enough water through the panels. I suspect it will but you never really know till you try. Maybe Mark (MAS985) or one of the other hydraulic experts will see this and can give some insight to it.

 

[mas985]

also my pump is 1hp 2 speed, will the low speed work with the panels mounted 14' high ?

Not well. Low speed would not have enough pressure to prime the panels so you would need to run on high speed for priming and then switch to low automatically which would require a controller. But even then, if the vacuum release valve is on top of the roof, the panels will lose prime when switching to low speed. Plus, the solar efficiency would probably not be very good on low speed. So overall, solar and low speed don't work very well together. You can make it work, but it is not easy. The following would be required:

Install the vacuum release ~6' above the pad.

Use an automated controller that would prime at high speed and then switch to low speed. However, if the controller also controls the solar valve, there could be a problem since most controllers will not allow low speed with solar engaged. So you would need two independent controllers, one for the pump and one for solar or simply have solar engaged all the time.

That is the only way I know of to get low speed to work on elevated panels.

 

[divinduck]

Thanks for the replys, I think I will just run the pump on high in the solar heat mode to heat the pool and adjust the timer for less runtime, and go back to low mode in summer and winter.