# solar observations- incredible

#### Davegvg

How do you get 68 feet of head ?

Panels are one story up and the pump assembly is located 8 feet from the lift.

Plumbing is 2 inch.

My blue and white showed like (it bounces and is not ideally located) 65-70 gpm.

normal filtering pressure at 225 watts is 8lb.

Solar at 745 watts (1 hp) is 20lb.

Filtering at 745 watts (1Hp) is 15lb

UD

#### mas985

TFP Expert
28 PSI * 2.31 (return head) + 3 (filter height) + 1 (suction head)= 68 feet of head

But now you are saying it is 20 PSI w/solar and 3100 RPM?

Also, what is the difference between normal filtering at 8 PSI and filtering at 15 PSI?

What does (1 HP) mean in terms of RPM?

#### Davegvg

mas985 said:
28 PSI * 2.31 (return head) + 3 (filter height) + 1 (suction head)= 68 feet of head

But now you are saying it is 20 PSI w/solar and 3100 RPM?

Also, what is the difference between normal filtering at 8 PSI and filtering at 15 PSI?

What does (1 HP) mean in terms of RPM?

PSI is completely variable depending on my pump speed and the solar tap being open or closed.
Calculating head based on pressure, nets a different head # at every pump speed.

Im not saying its 20 PSI with solar and 3100 RPM. At 3100 RPM and solar on it was 28 PSI.
I was pointing out that under normal HP's and speed my filter pressure is actually very reasonable.

1 HP is about 2600 RPM.

I normally run the solar tap at around 2600 RPM (not the 3100 I was running Sunday) and the display shows around 740 watts of power consumption. (I wanted to get every degree out the panels I could on Sunday and "juiced it" at the highest RPM I thought safe hence the 3100 RPM)

Filtering at 1830 RPM nets me about 8PSI of pressure which is my normal filtering speed - Im using about 220-30 watts of power.
Filtering at 2600 RPM nets me about 15lb of pressure with the solar tap closed and it goes up about 5lb with it open.

Uncle Dave

#### mas985

TFP Expert
Davegvg said:
PSI is completely variable depending on my pump speed and the solar tap being open or closed.
Calculating head based on pressure, nets a different head # at every pump speed.
Thats correct, plumbing head loss is dependent on flow rate so it will change with RPM as does filter PSI. The pump's head curve also changes with RPM.

Unfortunately, I am still not able to make sense out of your numbers. 28 PSI relates to ~68' of head loss and at 3100 RPM, the flow rate of the JEP 2.0 would be only 35 GPM not 70 GPM so the filter pressure must be high for some reason. To get 70 GPM, I would expect filter pressure to be around 24 PSI for 3100 RPM. Is the pump below the waterline and if so, by how much? Are you sure the filter gauge is working properly and goes to zero when the pump is off?

For now, we can assume the pump is putting out 70 GPM at 3100 RPM and with a 4 degree rise, that is 140k BTU/hr which is reasonable and about what I would expect from panels that size. The maximum output the panels could possibly produce is about 154k BTU/Hr without other losses/gains which would create a 5.4 degree delta. Unfortunately, this is still much less than the 313k BTU/Hr that you had estimated.

I checked Sunday in the area you mentioned and the weather was shown to be this which is a little warmer than what I was assuming. The dew point was still quite low which means that evaporation should have been fairly high during the day. So unfortunately, there still isn't any reason why you could have possibly gotten a 15 degree rise in a single day. The most I can come up with is 1.2M BTU/Day for the panels and 341k BTU/Day for the pool so a total of 1.5M BTU/Day which should have raise the pool temperature by about 9 degrees. BTW, that is about the maximum I have seen out of my panels.

So bottom line is I still can't explain why you would get a 15 degree rise. It just doesn't seem possible.

#### Davegvg

....Yet 2 independent sensors measured the same thing.

Uncle Dave

#### Davegvg

Weve had a heat wave in La again-

Heres teh week so far I worked at home this week form Tuesday on

This is from the same 2 sensors, pump speed 1000 watts_+ and 3000 RPM.

Tuesday I got a 7 degree rise low 80's outside

Wednesday I got a 10 degree rise high 80's low 90's outside.

Today I got a 12 degree rise.mid -high 90's today.

Im pretty pleased with what Im getting.

Uncle Dave