Florida 20x40 - Owner build

[mas985]

Sorry, TOTAL GPM from the pump should be the same.

But there is no good reason to plumb the panels as you have shown above. Simply connect the two sets at the headers and you have a better setup. No cross pipe necessary.

 

[Julianl50]

Sorry, TOTAL GPM from the pump should be the same.

But there is no good reason to plumb the panels as you have shown above. Simply connect the two sets at the headers and you have a better setup. No cross pipe necessary.

Halving the gpm seems worthy of investigation.

It would be great if there were more specifics about losses in passing to the next array.

Do you have any data?

Thanks

 

[mas985]

Halving the gpm seems worthy of investigation.

You are not really halving the GPM. The GPM in every part of the panel is exactly the same except the headers where it really doesn't matter. But the GPM is actually exactly the same in the scenario I suggested rather than the two you presented.

However, when you plumbing in series, you are basically doubling the head loss in the panels because when in series, head loss adds but when in parallel, it doesn't (for a constant flow rate through the panels. I can give you the extra cost for this in terms of running a VS pump with panels in series vs parallel but I still don't understand why you would this. There is only downside, no upside.

 

[Julianl50]

It would be a set of 8 panels in series with another set of 8. 384sf ea. group. Thanks

Also it looks like the 5gpm is the minimum.

 

[mas985]

But what are the panel dimensions?

 

[Julianl50]

I’m sorry but I just don’t get that. If the circuit is suction pump filter array array return. Doesn’t the gpm remain the same through each? Each item adds head loss?
The panels are 48sf ea.

 

[mas985]

Let me try explain this a different way and see if this help.

The reason they specify 5 GPM/panel is because that is where the efficiency of the panel levels out. It really is neither a minimum or maximum, just a recommendation. Higher flow rate does not gain much in efficiency so there is no point in going above that amount but you can always run at lower GPM/panel and take the efficiency hit which really isn't that much.



At half the flow rate, you only lose about 10% in efficiency.

If you target 5 GPM/panel, then yes, the series version requires half the flow rate as the parallel version. However, the temperature rise in the series version is twice as much because you have two panels in series at the same flow rate. This results in more heat loss (~10%).

But my point was that you can do exactly the same thing with the parallel version. If your goal is to reduce flow rate for pump energy savings, use a half flow rate per panel (i.e. 2.5 GPM/panel) so the total flow rate is exactly the same as the series version. Again, the consequence is double the temperature rise but it will be the same heat loss as the series panels and the same total flow rate as the series panels. Just implemented differently.

However, the big difference is in head loss. The series panels will have twice the head loss so pump efficiency will be less. This is why I was suggesting that if your goal is maximum heat transfer with minimum pump energy, then I would go the parallel route. It always wins in both categories no matter what the total flow rate may be when measured as dF/kwh.

 

[Julianl50]

Yes that makes sense.

I would appreciate the knowing the head loss for the series configuration.

Thank you.

 

[mas985]

What is the make/model of the panels?

Unless you have very restrictive panels, given that you have so many panels in both configurations, the head loss differences are probably not going to be very substantial. As long as you keep the total flow rate constant between the two configurations, both the thermal and electrical efficiencies should be about the same. There is a slight edge to the parallel configuration (~1%) but not all that much.

 

[Julianl50]

What is the make/model of the panels?

Unless you have very restrictive panels, given that you have so many panels in both configurations, the head loss differences are probably not going to be very substantial. As long as you keep the total flow rate constant between the two configurations, both the thermal and electrical efficiencies should be about the same. There is a slight edge to the parallel configuration (~1%) but not all that much.

I'm looking at these two. Swim joy for panels is 8k. vortex is 5k. Swim joy has 2" header and vortex 1.5" header.

 

[mas985]

The Vortex have about 3x the head loss of the SwimJoy but relative to the rest of the plumbing, it really doesn't make that much of a difference. The operating points for each configuration is as follows:

Vortex Series Fed (5 GPM/panel, 40 GPM total): 53.24' of total head, 273 watts, 1425 RPM
Vortex Parallel Fed (2.5 GPM/panel, 40 GPM total): 52.87' of total head, 270 watts, 1415 RPM

SwimJoy Series Fed (5 GPM/panel, 40 GPM total): 52.87' of total head, 270 watts, 1415 RPM
SwimJoy Parallel Fed (2.5 GPM/panel, 40 GPM total): 52.31' of total head, 266 watts, 1400 RPM

Again, since the total flow rate is the same at 40 GPM for all cases, the panel efficiencies should be close to identical.

 

[Julianl50]

The Vortex have about 3x the head loss of the SwimJoy but relative to the rest of the plumbing, it really doesn't make that much of a difference. The operating points for each configuration is as follows:

Vortex Series Fed (5 GPM/panel, 40 GPM total): 53.24' of total head, 273 watts, 1425 RPM
Vortex Parallel Fed (2.5 GPM/panel, 40 GPM total): 52.87' of total head, 270 watts, 1415 RPM

SwimJoy Series Fed (5 GPM/panel, 40 GPM total): 52.87' of total head, 270 watts, 1415 RPM
SwimJoy Parallel Fed (2.5 GPM/panel, 40 GPM total): 52.31' of total head, 266 watts, 1400 RPM

Again, since the total flow rate is the same at 40 GPM for all cases, the panel efficiencies should be close to identical.

That's great to know about the head loss and its impact between the two.

Is the series fed total head calculated with both arrays? 8 --> 8 --> .

What does the parallel Arrays run at the 5gpm/panel, 80gpm?

I really appreciate your support in this very interesting and complicated science. Thank you.

 

[mas985]

Total head is measured from the pump's perspective. It includes everything.

What does the parallel Arrays run at the 5gpm/panel, 80gpm?

Then it becomes an unfair comparison. Efficiency increases by only 10% but energy use goes up by almost 8x. You would be foolish to run at such a high flow rate. When comparing plumbing configurations, it only makes sense to compare at the same flow rates.

Head loss is proportional to GPM^2 and hydraulic HP by GPM^3.

 

[Julianl50]

Total head is measured from the pump's perspective. It includes everything.


Then it becomes an unfair comparison. Efficiency increases by only 10% but energy use goes up by almost 8x. You would be foolish to run at such a high flow rate. When comparing plumbing configurations, it only makes sense to compare at the same flow rates.

Head loss is proportional to GPM^2 and hydraulic HP by GPM^3.

Make sense about equivalent output either way.

My question about the parallel at 80gpm not so much as a comparison but if its cold and need/want the btus what's the cost and how loud is the pump going to be(rpms).

 

[mas985]

Instead of running at 80 GPM to get only 10% more heat, it would be far more cost effective to run 10% longer at 40 GPM to get the same amount of heat.

 

[Julianl50]

Instead of running at 80 GPM to get only 10% more heat, it would be far more cost effective to run 10% longer at 40 GPM to get the same amount of heat.

Got it.

Sometimes chasing the "most efficient" solution one can end up spending $$$$ to save $. Seems like even if I ran at 80 GPM it would only be at most $30 (over base circulation cost) per month on the coldest parts of the year.

I would like to know how many rpms it would take in the parallel mode to push 80 GPM. This is only for the noise factor. I'm assuming nearly 3k.

New topic:
The other item I could use some advice is the water features. I'm starting to doubt the necessity of the second pump.
I have 3 bubblers and 3 deck jets. The bubblers are in 12". The specs say 40 gpm ea will provide 20". Can't imagine wanting more height - Probably less.

I love tinkering with stuff so have two pumps and all that would be fun but do I need to invest $3200 extra into the pool? Only problem is the pumps are already here.

Thanks

 

[mas985]

To double the flow rate, you need to double the RPM. RPM and GPM are directly proportional to one another.

The impact to energy use is quite significant. For the SwimJoy parallel case, energy use goes from 266 watts to 1290 watts. For the SwimJoy series, 270 watts up to 1326 watts.

But you really don't gain much in terms of deltaF. You have 768 sq-ft of panels. At most, you can expect about 1500 BTU/sq-ft per day or 1152000 BTU. For a 38k pool, that is a heat gain of 3.6F. 10% of that is only 0.36F. Not worth it IMHO.

If you really need more heat gain, the most effective thing to do is to use a pool cover. You can raise temperatures 5-10F with just a cover.

As for the second pump, if running the bubblers and deck jets at the same time, that may mean less water to the pool returns because the pump can only produce so much flow rate. Best efficiency point for the Intelliflo 3 is around 129 GPM. You don't usually want to go much more than about 15% above that or 148 GPM. But to get to that point requires very low head loss plumbing and equipment. It wasn't clear which filter you plan on using but that can be critical for the total flow rate. But using a typical cartridge filter with the plumbing you laid out before, at most, you will get about 110 GPM total.

 

[Julianl50]

To double the flow rate, you need to double the RPM. RPM and GPM are directly proportional to one another.

The impact to energy use is quite significant. For the SwimJoy parallel case, energy use goes from 266 watts to 1290 watts. For the SwimJoy series, 270 watts up to 1326 watts.

But you really don't gain much in terms of deltaF. You have 768 sq-ft of panels. At most, you can expect about 1500 BTU/sq-ft per day or 1152000 BTU. For a 38k pool, that is a heat gain of 3.6F. 10% of that is only 0.36F. Not worth it IMHO.

If you really need more heat gain, the most effective thing to do is to use a pool cover. You can raise temperatures 5-10F with just a cover.

As for the second pump, if running the bubblers and deck jets at the same time, that may mean less water to the pool returns because the pump can only produce so much flow rate. Best efficiency point for the Intelliflo 3 is around 129 GPM. You don't usually want to go much more than about 15% above that or 148 GPM. But to get to that point requires very low head loss plumbing and equipment. It wasn't clear which filter you plan on using but that can be critical for the total flow rate. But using a typical cartridge filter with the plumbing you laid out before, at most, you will get about 110 GPM total.

I see. I thought there was a “tax” for increasing rpm from pressure increase.

Regarding the deltaF - It’s interesting that Solar literature doesn’t clearly explain this.
Edit: I mean the graph is there but not in terms like 3.6F or 3.24F.

I’m planning on use the plf35000 from aqua star.

I’ve never had a pool with water features so I can’t
say how much I’ll use it.

I think you are saying that it might not be so great to starve the rest of the pool’s circulation if using the features for any extended periods.

 

[mas985]

I see. I thought there was a “tax” for increasing rpm from pressure increase.

I don't understand, there is a huge tax. >4x the energy use.

Regarding the deltaF - It’s interesting that Solar literature doesn’t clearly explain this.
Edit: I mean the graph is there but not in terms like 3.6F or 3.24F.

Right, people don't realize that solar doesn't really add that much heat unless you have a huge array. However, over the course of a few days, you can generally get 2x-3x of that heat gain and maintain it depending on conditions. Again, if you want maximum heat gain, a cover is necessary.

I think you are saying that it might not be so great to starve the rest of the pool’s circulation if using the features for any extended periods.

Circulation doesn't need much. 1 hr per day is sufficient. Plus you still get some circulation with the features running. So worst case, you need to shut off the main returns while using both the bubblers and deck jets. Most deck jets don't require much flow rate. Have you picked those out yet?

Also, you don't really want to run water features that much because of PH rise and water evaporation which cools the pool down.

 

[Julianl50]

I don't understand, there is a huge tax. >4x the energy use.

Ok - The tax is the increase in head loss. Which requires more energy.

The deck jets are A&A Aqua Arch.