Save electricity with a 2 speed pool pump

[pinballlooking]

My brother is a pool guy so I was able to get this pump close to wholesale that helped.
Selling my old pump and getting this one at wholesale gave me a one year payback.
So I am very happy with it.
It also keeps my pool cleaner.

Our power cost .10 KWH fixed cost
We run it 10 hours a day 65 watts 30 days 19.5 KWH x .10 = $1.95 a month

[ICanHas]

Originally Posted by pinballlooking

My brother is a pool guy so I was able to get this pump close to wholesale that helped.
Selling my old pump and getting this one at wholesale gave me a one year payback. So I am very happy with it.
It also keeps my pool cleaner.

Our power cost .10 KWH fixed cost
We run it 10 hours a day 65 watts 30 days 19.5 KWH x .10 = $1.95 a month

So, how did you get a $100/month starting figure? I'm using my numbers here with your rate of 10c/kwh. Where it gets misleading is the decision to get the super expensive upgrade over the standard, more reliable two speed.

1.1kW = 11kWh/day, 330kWh/month. $33/mo energy bill.
230W = 2.3kWh/day, 69kWh/month $6.90/mo energy bill.
65W =0.65 kWh/day, 19.5kWh/month $1.95/mo energy bill.

$4.95/month saving compared to a two-speed pump that costs $500 less upfront. Using simple PBP (read: fictional) of 8.4 years, assume its as reliable as PSC (yeah...).

Why do I say fictional on PBP calculation? 99.5% of people do not live in the simple payback world where we'll let people borrow money with no additional return, or we can borrow without paying the cost of borrowing.

Assume you have no credit card bills. Assume there's no interest accruing accounts where you can shed interest cost by paying off $500 now.

Current best rate for 10 year CD is 3%. ($1K min deposit, not an unreasonable $25K minimum)
$500 spent now yields $648 at the ATM in 10 years.

Factoring this in, you'd be looking at 10 years. Probability of loss of deposit is far less than some power electronics drive parts going poof. Unlike gasoline or propane, electricity prices are not really volatile, so rate hike risk is lower.

This is why a lot of premium energy saving upgrades are a waste. You would be on track with using two speed pump with a decent real life ROI, but the incremental difference will never pay off. A 10 year PBP is unacceptable in the real world for something that doesn't have a 100 year lifespan.

Those embedded electronics have a pretty high risk of sudden failure.Before selecting "best" efficiency upgrade completely loaded with a whole bunch of proprietary electronic crap over "better" upgrade with less failure risk, you need to think like a lender.

If you're lending to people with poor credit, you have to charge a higher interest to account for risk of default or in this case, chance of loss due to circuit board frying. If you're lending to low risk borrower, or a low failure risk technology, the ROI rate does not need to be as high since the default rate is lower.

[pinballlooking]

The pump that came with my pool was costing me about $100 extra a month to run. It was just a 120v pump probably oversized for what was needed.

After selling my pump I was in this new pump about $400 so the payback is very quick.

Here is a example of one but mine only runs on high for 90 seconds not 2 hours.
http://www.inyopools.com/Products/18...FQQOaQod_ZkAmQ

For the record I did pay cash for the pump.

[ICanHas]

Originally Posted by pinballlooking

The pump that came with my pool was costing me about $100 extra a month to run. It was just a 120v pump probably oversized for what was needed.

Was the old setup a 1.5 hp pump running 24/7? You'd have to be running 1.39kW continuously to use 1,000kWh in a month. On 120v, that'll be 20A circuit maxed out around the clock (16A continuous allowed on 20A circuit by code).

I'm not arguing that going from A to B saves a lot, but B to C savings is de minimis despite the fact the cost to do A to C upgrade is dramatically more expensive than A to B upgrade. Just putting it up there, so people can consider this in making their upgrade decision.

For the record I did pay cash for the pump.

No, I meant, do you currently have existing credit card bills? If yes, making that one time $500 payment will save you on racking up interest by shedding what you already owe. Usually, credit card interest rates are very high, so the ROI from reducing high interest existing loan is quite strong.

If you have none, congrats!
Putting $500 in savings will let you withdraw $648 10 years later. If you prefer, some banks offer the option to pay out interest monthly and you withdraw $500 in 10 years.

[pinballlooking]

My old pump running cost was from a year over year est. So it would not be exact. This was before I got my TED 5000. It was 10-12 hour run time.

How much is does a B pump cost?

I totally agree if the pump cost is very big difference then B to C is not going to pay off at all.

[ICanHas]

Originally Posted by pinballlooking

My old pump running cost was from a year over year est. So it would not be exact. This was before I got my TED 5000. It was 10-12 hour run time.

How much is does a B pump cost?

I totally agree if the pump cost is very big difference then B to C is not going to pay off at all.

Looks like the Hayward SP15922S is $250-300 delivered, online retail price.
I didn't pick that model for any particular reason. I looked at a list of different pumps and that was just a good specs wise comparison with the one you bought.

It's just like buying a car. If you're replacing a 17mpg car, getting a 68mpg car rather than settling for a 34mpg (comparably equipped) typically do not make financial sense compared to the cost difference between the two.

There's a lot more to consider in selecting a car than transporting you between two points for x cost, but pool pump motor selection is all numbers game.

If a hybrid/electric gets a solo driving privilege in HOV lane like some states allow, the increased cost you paid for isn't for the gas. It's for the VIP pass. Looking at beyond YOUR money, someone else bought that pump to put it into service, so you're just passing on the inefficiency to someone else. This is why we have things like refrigerator trade-in credit program when you buy an Energy Star rated replacement one, so that the old one will not get put into service elsewhere.

I question the validity of real agenda behind "eco friendly" activities. The selling team obviously have great interest in taking old appliances out of circulation so that there's less competition to brand new equipment, which means $ $ $ $. People who talk carbon foot print, global warming whatever thinks they're doing a favor, but its the $ $ $ which motivates people to sell the old unit for $ $ $ to someone who will plug it in and use it rather than breaking it so that it can not be made functional economically and having it recycled for FREE. so the rebate's gotta be competitive with what they'll likely get if they were to dump it on Craigslist.

[Servicetech]

Residential demand charges are rare. Time of use rates are rapidly becoming common.

[NiHaoMike]

Multi speed PSC motors are an ugly hack. True multi speed (pole switching) motors are much better, but I imagine there must be some compromise in there to let it work with multiple pole numbers. Also, three phase motors are more efficient than single phase, which can easily offset the efficiency loss from a VFD.

That said, you could also consider multiple pumps either running different zones or combined with low restriction check valves.

[ICanHas]

Thing about three phase motor is that rotation field is provided by the power source from no load to full load.

For a single phase motor, the capacitor size needed is contingent on load. So, there is no magic bullet capacitor size that covers from 0 to full load.

Capacitor run motor gets nearly perfect power factor, less torque ripple and higher efficiency. It's not a huge difficulty to use two run caps, one for low and one for high.

Run capacitor improves efficiency and it's ideal for things like pump where load doesn't vary much. It's not really good for something like a table saw where it runs at zero load for a long time and load is applied rather suddenly.

ECM is not a regular three phase motor. It's a SYNCHRONOUS permanent magnet rotor 3ph motor. The permanent magnet rotor means the power isn't used to induce (hence the name induction motor) magnetic field in the rotor.

A synchronous motor will run at 1800 or 3600 PRM.
Look at page 5 here. A 0.75kW/1 hp synchronous motor will get close to 90% efficiency.
http://www2.schneider-electric.com/d...on_control.pdf

An induction motor REQUIRES a slip to run. A 3450RPM motor is really 3,600RPM with a 4.2% slip, so you know even if you took away bearing and resistive losses in the coil, you can't get better than 96%.

So, I dispute the claim that low THD VFD + 3 ph induction motor in 0.5 to 2.0 hp range can surpass the best available capacitor run single phase induction motor in 0.5 to 2 hp range to justify using reliability reducing, cost increasing electronic complication.

For something like a pump motor, one should keep up with the KISS principle and avoid introducing electronic drives into the system.

Assume 120v, or 208 to 240v single phase power source.

Compared to a high efficiency permanent magnet synchronous motor, I seriously doubt VFD + 3 ph PMDC will achieve the plug-to-shaft efficiency surpassing it.

Consider these requirements too:
MTTF under field conditions (extreme temperatures, power surges) not less than AC rotating machine.

THD not to exceed 10%.

[NiHaoMike]

A synchronous motor cannot be made to operate with different pole numbers. While a squirrel cage rotor will form as many pole pairs as the stator is providing, a permanent magnet rotor can only be built with a fixed number of poles.

Probably not applicable to a centrifugal pump or fan load, but induction motors can beat synchronous when driving widely varying loads.
Induction Versus DC Brushless Motors | Blog | Tesla Motors

And some motors don't mind 10% THD at all - in fact, the Prius motors are driven with square waves at high speed as it ends up more efficient overall. It should be noted that it's the current that really matters in motors, not the voltage.
VH boost

Interesting things happen in the 30 - 40 MPH region, especially in EV mode.
I know from some other observations that the inverter drive signals for MG2
move from a multiple-kilohertz PWM regime into simply switching 3-phase square
waves at the motor's native electrical rotation speed, because it's more
efficient and the motor is turning fast enough to smooth out any torque ripple
that would produce.