144 BTUs per pound of ice, plus 64 BTUs (96-32) for raising the ice water to pool temp. 60lbs of ice will absorb 12600 BTUs. (210*60)

It take 1 BTU to change 1 pound of water 1 degree. A gallon of water weighs 8.4 pounds.

A 10,000 gallon pool has 84,000 pounds of water.

12,600/84000 = 0.15 degrees

However - The latent heat of vaporization of water is...970.4 btu/lb. If you buy a small cooling tower and sacrifice 100 gallons of water, you can cool the pool down a bit under 10 degrees.

https://www.poolsupplyunlimited.com/glacier-gpc-210-pool-cooler/20948p1

This engineering moment brought to you by... Mi-Grid Remote and Off-Grid Power Solutions l Renewable Power Management Systems l Solar Power Systems l Backup Storage l Solar Power Kits

BTW - I would really like a pool chiller. In the heat of summer, the water temp can get to the mid 90's. Right now, we've had 2 weeks of rain and the temp was down to 84. 2 days of sun and it's 89

Firstly, I know nothing about electric motors. Secondly, I'm looking at a 220-240V 5 hp two speed (3,450 RPM/1,725 RPM) pool pump that operates at 16.4A on high and 4.8A on low. Please riddle me this, Batman. Does the electric motor rate at 5 hp only at the higher RPM or does it rate at that level at the lower RPM, too? If the 5 hp rating is only at the higher RPM, what would its hp rating be at the lower RPM?

Gracias!

HP=Speed x Torque/5250

If you had the same torque at low speed the HP would be 2.5

There are 750 Watts/HP

High mode 230V * 16.4/750 is 5.03 HP

But you have 230V * 4.8/750 Amps on low speed, which is more like 1.5 HP on low.

speaking of 12.5 cents
 

I remember my old man telling me when he first started working and was starting a family he got 12.5 cents an hour. So an 8 hr day, $1.00

He thought he was doing great. But also he said when he moved into his first house, that he had built, it cost just over $300. That house is still standing.

My first job was $6,500/yr, I thought I had it made in the shade. A new Corvette at that time was $10,000

Thank you, 1990!

Sorry for resurrecting this thread, again, but I'm trying to figure out how to determine the kw/h consumption of electric pool pump motors. I think, maybe, M.D. gave me/us the formula, below, but I'm not sure. Currently, I'm looking at a 230V 2hp motor that draws 1.8 amps with a power consumption of 414 watts.

If I understand M.D.'s below formula, correctly, do I end up with a kw/h usage of .60949? And, if I'm incorrect, could somebody please hold my hand through the correct calculation? Thank you very much!

A 2HP pool pump will not draw 414 Watts/1.8 Amps. A regular 2HP pump.

1HP = 744 Watts
2HP = 1488 Watts

BUT

There is a service factor, typically 1.85.

So the pump will use 2750 Watts and draw 12.5 Amps.

IF it is a 2HP pump with a VFD (Variable Frequency Drive), you can program it to run at a lower speed and draw less current and use less Watts. On a 2HP Ecostar, this would occur at around 1900 RPM, and the pool would flow about 50GPM, depending on the back-pressure of your filter.

https://www.hayward-pool.com/shop/en/pools/EnergyCalculator

Here is the spec sheet for that 2HP pump/motor. What am I missing or not understanding, here? Ah, maybe what I'm not understanding is the spec sheet shows
the ratings under Efficiency Mode...

Thanks!




http://forums.pelicanparts.com/uploa...1475944616.jpg

red-beard: what do you use to switch speeds? A simple timer and a relay?

http://www.ecopoolpumps.com/Media/EcoPumpEP8Specs.pdf

It is a VFD. Not well explained, but it is a VFD. Seems to be "Phase modulation" instead of frequency modulation. The pump speed it reduced. The volume goes down with the speed of the pump, but the power goes down with the square of the speed.

EcoPump Specs | EcoPump

In the commercial section, they show an external VFD unit for controlling the motor.

Commercial Pool Pumps | EcoPump

Thank you, Red-beard!

I meant what tells the VFD to switch speeds? Does their VFD have a timer function? Or do you have some sort of external speed select?

The information on that site is scant.

On my pump, it has timers built in. Each setting has a speed and turn on time. Depending on the type of pool automation you have it can be controlled externally.

My Automation is older and can't interface for direct speed control. It does have relays which can be connected to run the pump at pre-programmed speeds. With the "spare" relays, I can run 7 speeds and "off".

On further reading, the Eco-pump is not computer controlled. It is similar to a two-speed pump and it operated that way with relays for two sets of windings. The thing that sets this pump apart from regular two speed pumps is that it is a seriously oversized pump and it is run at much lower speeds.

The "low speed" will produce about 65GPM, while the "high speed" will produce about 170GPM, depending on back-pressure. Low Speed = 414 Watts, my ESTIMATE on high speed is 3140 Watts. If full speed is 2.6HP@3600RPM, High speed is 3160 and low speed is 1225 RPM.

Variable Speed Pool Pumps | EcoPump

It is definitely less expensive and easier to implement for older automation than a traditional VFD. Where the traditional VFD excels is being able to adjust the speeds to the LOWEST settings necessary to keep the pool clean.

My pool is run like this:

6AM-7AM 2600RPM (fast skim)
7AM-Noon: 1200RPM (continuous clean)
Noon-12:30 2600RPM (Spa mode, 1/2 hour circulation)
Noon-5PM: 1200RPM (continuous clean)
5PM-6PM 2600RPM (fast skim)
6PM-10PM: 1200RPM (continuous clean)

My VFD@1200RPM=85 Watts, 13.5 hours/day=1147.5 Watt-hours
My VFD@2600RPM=638 Watts, 2.5 hours/day=1595 Watt-hours

VFD total = 2742.5 Watt-hours

Total operating cost per day = $.195/day, monthly cost $5.85
My old pump (1HP, 14 hours per day)=19,270 Watt Hours, or $1.37/day - $41.10/mth
Savings=$35.25, or $423.00/year

This is a little higher than my original post, but these speeds skim better than my original speeds.

My turnover per day is 51,450 gallons/day, Pool is 24,500 gallons -> just over 2 turns per day.

If I used the "2HP" pump, to get ~50000 gal/day, only using "low Speed", 13 hours per day, 5382 Watt Hours
Compare to 2742 Watt Hours with my VFD same flow per day.
My old 1HP pump, 75GPM, 11 hours per day, 15311 Watts (I used to run 14 hours, though)

Thank-you. Good info.

Your pump is completely off 10PM-6AM?

Yep, off from 10PM-6AM. I've considered reducing speed and running it 24 hours.

In fact, looking at my speeds and flow rates, I already reduced the rates to 2400/1000 RPM. Looking at the flows, for maximum efficiency, I could drop the high speed to 2050 and the low speed to 800 and increase time to 21.5 hours and cut electric usage to 1.5kWh/day. The problem is my stupid pressure side cleaner pump is 1500 Watts. It uses 3kWh/day.

Really good read here on VFD pool pumps.

http://www.nrel.gov/docs/fy12osti/54242.pdf

There is an article by someone on removing the pressure pump and using a diverter valve and calibrating the flow. If what they say would work, I could reduce my power down to about $3/month.

Update: It has been a year since I switched the pool pump. My electric usage is down $193.33 or 2788 kWh. Compared to 2 years ago, my savings is $302.06. This seems about right, since 2 years ago I was running a 1 hp pump and 6 months before I changed the pump, I swapped in a 1/2 hp pump.

Price for the VS pump $775 vs. $546 for straight replacement, for a delta of $229.

Next stop: re-plumbing and programming to eliminate the separate pressure side pool cleaner pump. Several people have used the VS pump to power the pool cleaner.

You remove all orifices on the line and plumb a valve connection from the pump discharge. The pool cleaner is calibrated by checking wheel speed. Change pump speed until you get proper cleaner wheel speed.

I estimate the 3/4hp pump uses almost as much energy as the new Variable Speed pump.

how much power is used in the VSD to convert 220v 1 phase
into 3 phase power ?
I assume the VS pump runs on 3 phase and speed is controlled by frequency
rather then a two/three speed motor windings that stay at 60Hz
without variable frequency like a common multi-speed fan

If it's an electrical type phenomenon then it's over my head and i know nothing about it and won't comment.

But if it's physical (mechanical) vibration that is of concern I am qualified*


1st critical speed of a motor is typically well above the potential running speed so that type of harmonic is not a problem with VFDs. (unless you start talking about really large motors (like in the thousands of HP).

But if you are talking about the natural frequencies of related equipment such as structures or piping etc. that is a potential problem with VFDs.

But it's so easy to correct.
The vibration responses to varying speeds can be easily mapped for each application and problem areas can be either addressed or avoided.

1) add or remove a little mass.
2) change the stiffness
3) raise or lower the rpm by 100.


But too often companies start installing these things and don't have properly trained engineers who know how to set them up correctly or deal with the differences.
That creates all sorts of headaches.







*Last time I checked there were 83 vibration analysts in the US certified to level III in accordance with ISO 18436-2.

My certification number is M-121262-01 :D




PS I have a VFD pool pump just like redbeard, and I have a higher pressure cleaner pump that runs 1 hour a day.