Solar plumbing

[Telemachus]

I am in the process of installing my own pool solar.

Pretty tight space on the outlet of my Pentair Quad DE filter.

The solar lines will run in the ground adjacent (closest to the camera) to the equipment.

Can I get some thoughts on how to plumb this tight space?

 

[ajw22]

I would rotate the filter 90 degrees to the left so the inlet/outlet points directly toward the pump and heater. And if you can, move the filter a step or two back to get some extra room.

That gets the pipes away from the blower pipe and gives you room to connect your solar pipe.

 

[BuffLosolja]

Is this a solar tube heating you are thinking of? I was just about to post and research this as well. Definitely will be following.

 

[ajw22]

Is this a solar tube heating you are thinking of? I was just about to post and research this as well. Definitely will be following.

You may find this helpful...

Solar Pool Heaters - Further Reading

www.troublefreepool.com

 

[Telemachus]

I would rotate the filter 90 degrees to the left so the inlet/outlet points directly toward the pump and heater. And if you can, move the filter a step or two back to get some extra room.

That gets the pipes away from the blower pipe and gives you room to connect your solar pipe.

I like the current orientation of the filter, because I have a drain right underneath the clean out port..

Pentair putting the outlet on the bottom sure complicates things.

I'm hoping that maybe I can get 2 tees into the output line

 

[ajw22]

Others have connected a pipe to the drain to divert it in a better direction.

 

[Telemachus]

Others have connected a pipe to the drain to divert it in a better direction.

Good point. Thanks

 

[Telemachus]

Could I just cut the output line and put 2 elbows there, and thread them up through the opening next to the pump? That would give me verticle to add the actuator and one way valves

 

[ajw22]

You can go vertical at some point to get some space.

I would reroute the pipe around your pump and figure out where to tap your solar into that routing. Someday that pipe over your pump will become a big problem when the pump needs to be replaced.

Might as well free the pump while you are putting in solar.

 

[Telemachus]

Brilliant idea. I can barely access the panel to the pump as it is.

Edit: unfortunately, the pool builder put all the fittings adjacent to each other. Redirecting around the pump will require replumbing all of the heater as well as there is a small bypass between the inlet and outlet of the gas heater...

 

[ajw22]

Brilliant idea. I can barely access the panel to the pump as it is.

Take the pipe back from the pump a good bit so you don’t crowd access to the pump.

 

[Telemachus]

Is there a reason why solar needs to be plumbed in right after the filter?

In my setup the pipe on the very bottom right (after the salt cell and spa/pool valve) is right by where my pipes for solar come up out of the ground. That pipe feeds the pool.

In theory, it should be lower pressure there than the water coming out of the filter because the gas heater and SWC each drop the pressure. That should help reduce barotrauma to the panels over time.

The downside is, the water overflowing to the spa through the red handle valve wouldn't be heated, but I would imagine that is negligible. If I want to heat the spa above the temp of the pool I would just use gas.

 

[ajw22]

See this discussion on the risks of hydrogen gas from the SWG into the solar panels…

SWG BEFORE the solar panels?

Looking at going to salt but would need to install the generator before the solar panels in order to avoid re-piping most/all of the return piping. I know all the SWG people say to install after a heater but I assume that's because gas heaters and heat pumps all have metal heat exchangers in...

www.troublefreepool.com

 

[Telemachus]

Ok so I'LL avoid plumbing in the panels after the SWG.

It's still going to be much easier to plumb it in after the gass heater. Any real reason people plumb it in before?

 

[magiteck]

You want the solar before the gas. Solar heating relies on temperature differential. If you heat the water before it enters the panels, you decrease that, and might even make the water warmer than the surface (effectively turning the panels into a radiator/cooler).

You want to get any potential solar heat gains, and then have the gas heater supplement that when needed.

Edit: removed misleading sentence.

 

[Telemachus]

You want the solar before the gas. Solar heating relies on temperature differential. If you heat the water before it enters the panels, you decrease that, and might even make the water warmer than the surface (effectively turning the panels into a radiator/cooler). The panels also reduce flow, which could impact the gas heater performance.

You want to get any potential solar heat gains, and then have the gas heater supplement that when needed.

I can't really imagine a scenario where I would run the gas heater and solar heater at the same time...

If the panels reduce flow, that is an argument to place them after the heater, correct?

 

[ajw22]

If the panels reduce flow, that is an argument to place them after the heater, correct?

No, the overall flow is the same regardless of before or after.

 

[magiteck]

If the panels reduce flow, that is an argument to place them after the heater, correct?

No, the overall flow is the same regardless of before or after.

ajw is correct, disregard that piece. I was reading something unrelated regarding flow and crossed mental streams.

Many folks like to run solar and gas at the same time to reduce gas cost. I.e. if your solar panels can increase the water by a couple degrees, then that’s less work for your gas heater to get to / maintain temp. Solar has to come first for this to make sense.

If you never run both at the same time, then the order is probably less important.

 

[Telemachus]

ajw is correct, disregard that piece. I was reading something unrelated regarding flow and crossed mental streams.

Many folks like to run solar and gas at the same time to reduce gas cost. I.e. if your solar panels can increase the water by a couple degrees, then that’s less work for your gas heater to get to / maintain temp. Solar has to come first for this to make sense.

If you never run both at the same time, then the order is probably less important.

Well... I'm talking hypotheticals here. All I've had for the last 14 years is a gas heater and a solar cover... meanwhile jealous of my neighbors who swim 9 months out of the year.

Maybe you can help me understand this conceptually.

Let's say on a warm SoCal day in February when it's 72' outside, I decide to turn both on at the same time to warm up my 50' water to 76' for President's day weekend.

The differential on the solar controller is going to keep it flowing through the panels until the water temperature is a few degrees lower than ambient. Then it will be bypassed.

The gas heater will get it to that setpoint sooner, and will keep going until it hits 76.

I don't see the mechanism if this changing depending on the order of the two heaters...

Maybe it depends on where the water temperature probe is?

 

[magiteck]

The temperature rise coming out of the gas heater is a lot more, and could be 10+ degrees.

Temperature of water exiting pool heater

Hello, I know there is a lot of variables like BTU, water temp in/out of heater and ambient temperature but does someone know what the temperature is that exits a gas water heater? Thanks, Joe

www.troublefreepool.com

For a properly functioning solar heater, it’s much lower, maybe just a couple degrees.

So pretend you have:
Air - 70
Water - 50

With solar first, the incoming water might get heated to 53, and then further heated by the gas heater to 65 (before mixing with the rest of the pool water).

If you go the other way, the gas heater might rise the temp from 50-62 (same BTUs added), but then because the differential is now lower for the solar it might only get you a 2 degree rise instead of 3, so the final output temperature is 64 instead of 65.

Tl;dr: the greater the difference between the surface temperature of the solar panels and the water flowing through, the more heat energy transferred to the water.