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scooper

join:2000-07-11
Youngsville, NC
kudos:2

Is there such a gadget ?

Scenario - Heat pump with pool pump.
I'm on a electric rate plan that hits a premium for highest 15 minutes of peak use for the month.

What I'd like to see is some gadget that when the heat pump is on, an interuptor is turned on for the pool pump, and conversely - when the heat pump turns off, said interuptor turns off to let the pool pump run.

Is such a gadget possible and /or available ?

If there could be 2 such high load sensors, if the second one would turn off the interuptor if power is available on the electric tank water heater (sort of reverse of the one on the heat pump).

So - ideally,

Pool pump can run when the tank water heater is on (regardless of state of the heatpump)

Pool pump can run when Heat pump is off (regardless of state of the water heater).

Oh - and this ideal device communicates over the powerline to the interuptor....



pike
Premium,MVM
join:2001-02-01
Washington, DC
kudos:3

How is your pool pump currently controlled? A timer? Where is the air handler located in regards to your main panel?

I don't think you really need to complicate it with any current sensors or powerline comms. I would run the pool pump's motor feed through a normally closed contactor and put the coil on the thermostat circuit. So whenever a call for HVAC is made, the contactor opens the circuit to the pump. I might also get a little fancy with time delays but not totally necessary.



John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to scooper

Simple relay logic and appropriately sized contactors would work fine.



mix

join:2002-03-19
Utica, MI
reply to scooper

You could basically wire the 24v from your heat pump thermostat to a contactor that controls the 240v (or whatever ac voltage) to your pool pump. This a very simple circuit. You could probably use a contactor designed for a HVAC applications and they cost around $25. Might need to be a normally closed type though.



tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
kudos:9
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reply to scooper

As other have posted what you are asking is pretty simple logic circuit. Doing it wired would be the easiest. If you really need wireless might be able to hack some key chain type RF remote controls but unless it it out of the question I'd run wires.

I understand you are trying to reduce peak power consumption but I don't understand the water heater logic? Is the heater electric, if so wouldn't you want the other loads to be off when water is being heated.

Are there other high power loads, Electric dryer or range may want to add them to the mix.

/tom


scooper

join:2000-07-11
Youngsville, NC
kudos:2

1 recommendation

reply to scooper

Ok -
The electric water heater is on a timer that permits it to power on only during off peak hours.

I do have a timer on the pool pump - but I would like to run it during the peak time of the hot afternoon to pickup and circulate heat from the sun. This is where having the contactor controlled by the heatpump 24VAC comes in. Naturally, the heat pump runs more the hotter it gets. The power for the pool pump flows from main breaker panel inside house, to breaker panel outside house then underground to shed power panel, where the timer for the pump is and also where the pump gets it's power.

Since we're talking about a different building - that;'s why I would want this to be wireless for the communication to the contactor (for the poolpump).

the more I verbalize this - the more it would just make more sense to just set the pool pump timer so it wouldn't come on during peak times and manually turn on pump when I want to swim (after setting the heatpump to not turn on while swimming). After all - the heat from the sun would still collect on the sunny part of the pool.

Thanks for your ideas. I'll revisit this idea later...


patcat88

join:2002-04-05
Jamaica, NY
kudos:1
reply to scooper

I've never seen TOU rate plans make sense unless you can say "shifts over, everybody go home [the rock crusher is until off until 9 PM]". Paying 25% less off-peak makes no sense when you will pay 300% more peak. To cut your power usage down enough for TOU to pay off, you will need to flip the main breaker to your house.

Highest 15 minute peak/"demand charge" sounds 100% commercial tarrif. Are you in an office building or strip mall? This doesn't sound like a house/residential tarrif.

Speaking about electric water heaters. All that I know of come with 2 heating elements and a 2 stage thermostat. You could disconnect one heating element if you are desperate to cut the peak amps. Yes, that is a code violation/UL violation.

Considered a water tank, a mini hydro dynamo, and a grid tie inverter to lessen your peak load?



StillLearn
Premium
join:2002-03-21
Streamwood, IL
Reviews:
·AT&T Midwest
reply to scooper

said by scooper:

Since we're talking about a different building - that;'s why I would want this to be wireless for the communication to the contactor (for the poolpump).

The rest of this presumes you are running 3 or more power wires (including neutral) to the pool house:

Is the pool pump 240 volt? If it is 120 volts, you could move the shedable load to one leg of the 3-wire AC, and put the lights etc on the always-on leg. Then you could do your switching inside the house.

If the pump is 240 volts, I have a weird one for you: In the house you use a SPDT relay to power one of the legs of the AC going to the pool house with either the same side of the AC as now, or from the other side of the AC service. Energize the relay near the fuse boxes, and 240 volt loads for the pool house go dead (same voltage both sides). The 120 volt loads all stay alive, although there would be a flicker for some loads during the switching. I am not saying that this is proper; let others determine that. I am saying it would work.

scooper

join:2000-07-11
Youngsville, NC
kudos:2
reply to scooper

Yes this is a residential tariff. I save $40 -$60 per month on my electric bill (and some summers as much as $80 - $100 / month) by following some easy to live with contraints. Not everyone can follow these - for example - a family will little ones on diapers would not find this convient at all.

Yes I have an electric clothes dryer - but we do laundry on the weekends (off peak) time. The oven/ microwave is electric, but we don't usually run the high wattage big oven during peak time. We are using a gas cooktop. Likewise - the 40 gallon tank is plenty for the 2 of us, and it does a fine job of keeping up with the laundry as well.

We do have an electric tankless water heater for the kitchen, but again - we're smart about using it during peak hours.

The things I don't "control" - heatpump / HVAC system, well pump (for house water) and lights/electronics. I do use a programmable thermostat for the HVAC, and it helps to some extent.



tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
kudos:9
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reply to StillLearn

said by StillLearn:

Is the pool pump 240 volt? If it is 120 volts, you could move the shedable load to one leg of the 3-wire AC, and put the lights etc on the always-on leg. Then you could do your switching inside the house.

That will have no effect on peak power.

The meter is measuring peak power consumption of the load, not peak current of either leg.

/tom


StillLearn
Premium
join:2002-03-21
Streamwood, IL
Reviews:
·AT&T Midwest

said by tschmidt:

The meter is measuring peak power consumption of the load, not peak current of either leg.

If there is the same in-phase voltage on both power wires for the pump, the pump will draw no power.


tschmidt
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join:2000-11-12
Milford, NH
kudos:9
Reviews:
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said by StillLearn:

If there is the same in-phase voltage on both power wires for the pump, the pump will draw no power.

Sorry about that I misunderstood what you were proposing.

Agree, feeding a 240v device from the same leg effectively turns the device off. 120 v devices remain on except for momentary switching transient.

/tom

antbhill2
Premium,MVM
join:2001-02-28
Northern VA
reply to StillLearn

said by StillLearn:

Is the pool pump 240 volt? If it is 120 volts, you could move the shedable load to one leg of the 3-wire AC, and put the lights etc on the always-on leg. Then you could do your switching inside the house.

If the pump is 240 volts, I have a weird one for you: In the house you use a SPDT relay to power one of the legs of the AC going to the pool house with either the same side of the AC as now, or from the other side of the AC service. Energize the relay near the fuse boxes, and 240 volt loads for the pool house go dead (same voltage both sides). The 120 volt loads all stay alive, although there would be a flicker for some loads during the switching. I am not saying that this is proper; let others determine that. I am saying it would work.

I suspect either of these approaches will not meet code. Don't have a code book to check, my understanding is that any disconnecting device needs to simultaneously open all hot poles of a circuit. Therefore, leaving one hot and interrupting the other could be an issue.

For the SPDT idea, depending on how it is done and the wiring fed from the subpanel, feeding both of the hot legs from a single source could cause overloading of neutral conductors.

Zach1
Premium
join:2006-11-26
NW Minnesota

1 edit
reply to scooper

Since no budget has been proposed and we have no idea how far outside the box you are willing to consider.....

How about figuring out a way to reduce power consumption while maintaining some circulation?

Here is a pump that integrates an EC motor and timer?

»www.pentairpool.com/pool-pro/pro···p-77.htm

Just did a job at a hotel where a commercial version was used. Pool pumps are usually ho hum but this thing was pretty amazing. A low speed circulation mode for a typical residential pool would draw 150-250 watts. On the hotel pool, full power runs 3.5 Kw and circulation mode was set at 0.75 Kw

Or you could use your current pump with a 3-phase motor and VFD. The problem here could be nuisance tripping of the GFCI feeding the drive. I know there isn't a problem with a class B 30 ma trip but a class A may prove to be a problem. An yes, they do make several that are designed for single-phase input. It's also possible to use a unit designed for a 3-phase input but you must derate the drive by 50%. Using this setup it's probable to reduce power consumption to around 200-300 watts while maintaining sufficient circulation to take advantage of daytime solar. A timer would still be required to control runtimes and speeds.

Last, you could plumb in a small bronze or SS calculator pump in parallel, using check valves and proper plumbing techniques to prevent back flow with your current pump. For picking up some solar heating, the smaller pump would run. For the off-peak heavy lifting your current pump would run as it does now. Still would require a timer and maybe a contactor or two.

Since industrial and commercial is what I do and I'm up to my eyeballs in industrial control stuff, PLCs and VFDs are staples and used for all kinds of off-the-wall stuff. It looks like an Allen-Bradley delivery truck exploded in my shop
--
Zach


theboz1419

join:2003-02-12
Elgin, IL

1 recommendation

reply to scooper

not sure if this would work with a heat pump or not. But, saw this on a This Old House

»www.hotspotenergy.com/pool-heater/



John97
Over The Hills And Far Away
Premium
join:2000-11-14
Spring Hill, FL
kudos:1
Reviews:
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reply to Zach1

said by Zach1:

Here is a pump that integrates an EC motor and timer?

»www.pentairpool.com/pool-pro/pro···p-77.htm

Coincidentally, I am looking at that exact model to replace my pool pump to save on the electric bill.
--
So put me on a highway, and show me a sign.
And take it to the limit one more time...

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel

1 recommendation

reply to patcat88

said by patcat88:

Speaking about electric water heaters. All that I know of come with 2 heating elements and a 2 stage thermostat. You could disconnect one heating element if you are desperate to cut the peak amps. Yes, that is a code violation/UL violation.

That would do nothing, as the two heating elements never operate simultaneously to begin with.


StillLearn
Premium
join:2002-03-21
Streamwood, IL
Reviews:
·AT&T Midwest
reply to Zach1

said by Zach1:

Since no budget has been proposed and we have no idea how far outside the box you are willing to consider.....

An electrician should be a person who tends to think in-the-box (pun intended).

We don't know if the pump is 120 or 240. We don't know what kind of circuits run to the pool house. We don't know if the wires are in conduit that could accept one or two more wires easily. We don't know the distances.

Home automation modules could carry the signal probably. Given the purpose, an expensive really high-reliability system is not needed. Still, running new wires can be easy enough, and he could have the highest reliability at a reasonable cost.


nunya
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
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reply to scooper

There's nothing magical or mystical about this. The OP is on a "peak" plan. Any additional load, without regard to the voltage, is included in the peak. Here is the US, we are billed in "kilowatt hours".
Personally, I would never put up with the inconvenience vs. savings on one of these plans.

Other than changing plans, here's how I would address the issue:
Forget wireless - too complicated. Use the LV A/C circuit to your advantage. Make sure the LV transformer in your furnace can handle the load of an additional contactor and on-delay timers (also the t-stat!).

I would have the pool pump wired to a locally powered line voltage NC contactor with a 24V on-and-off delay timer relay set to 5 seconds.
I'd install an on-delay module on the A/C condenser set to 10 seconds.

When the 24V kicks on for the A/C, it starts the 5 sec to open the NC contactor at the pool pump. It also starts the 10 second on delay timer at the A/C.
When off, there's a 5 second delay for the pool pump to start again.
There will always be a 5 second delay between the motors stopping / starting.

Seems like a lot of work and expense though.
--
If someone refers to herself / himself as a "guru", they probably aren't.



Jack_in_VA
Premium
join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
reply to John97

said by John97:

said by Zach1:

Here is a pump that integrates an EC motor and timer?

»www.pentairpool.com/pool-pro/pro···p-77.htm

Coincidentally, I am looking at that exact model to replace my pool pump to save on the electric bill.

Are you planning on pumping the same amount of GPM? A 1 hp load (746 watts) is the same regardless of what is supplying the power to it. Of course if the speed and capacity is reduced then there would be a savings.


StillLearn
Premium
join:2002-03-21
Streamwood, IL
Reviews:
·AT&T Midwest
reply to nunya

said by nunya:

I would have the pool pump wired to a locally powered line voltage NC contactor with a 24V on-and-off delay timer relay set to 5 seconds.
I'd install an on-delay module on the A/C condenser set to 10 seconds.

My interpretation is that the peak load is measured by the consumption in a given 15 minute period. So having the pool pump overlap the heat pump load for a few seconds would not increase the power consumption significantly. If my interpretation is correct, you would not need a timer.

scooper

join:2000-07-11
Youngsville, NC
kudos:2
reply to scooper

The poolpump is a Pentair 1.5 HP Superflo, (energy efficient model) running on 240V. Seems like it is drawing around 1000-1400 watts (running) . Comparable to a 3/4 HP Hayward Powerflo 2 that I used inbetween replacing pumps.

Yes - now that I spend time at TFP.com, I know about variable speed / 2 speed pumps. What I should have bought was a 1HP superflo 2 speed - but unless the motor goes out very short term - I don't see replacing it until it does. I'll revisit the 2 speed motor option at that time.

This whole idea was a see if other options are available - but it is probably for moot right now - got a text from the wife at work today that the heatpump (outside unit) is not working / making cold air. There is a buzz, and some of the sides are hotter than ambient, but the fan at the top is not turning. Calling HVAC company tomorrow to see what wore out (this is a 1997 Trane XE1100 4 ton unit). In any event - the easy way to prevent the peak is to simply use the existing timer so the poolpump is running during offpeak hours - and so the timer has been set.

So - rather than play with this - I have bigger fish to fry at the moment.

I thank you all for your ideas.



djrobx
Premium
join:2000-05-31
Valencia, CA
kudos:2
Reviews:
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reply to antbhill2

my understanding is that any disconnecting device needs to simultaneously open all hot poles of a circuit

Yes, but a timer (or in this case, a custom logic circuit) is not a disconnecting device. The disconnect is something separate that will definitively cut power to both legs, and must be within visual range of the pool pump.

"680.12 Maintenance Disconnecting Means. One or more means to simultaneously disconnect all ungrounded conductors shall be provided for all utilization equipment other than lighting. Each means shall be readily accessible and within sight from its equipment and shall be located at least 1.5 m (5 ft) horizontally from the inside walls of a pool, spa, or hot tub unless separated from the open water by a permanently installed barrier that provides a 1.5 m (5 ft) reach path or greater. This horizontal distance is to be measured from the water's edge along the shortest path required to reach the disconnect."
--
AT&T U-Hearse - RIP Unlimited Internet 1995-2011
Rethink Billable.


nunya
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join:2000-12-23
O Fallon, MO
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reply to StillLearn

They pick the 15 minute period with the highest load. You try an eliminate higher loads.
Picture a chart with usage and a 15 minute "slider" that goes over the top. The power company goes along with the 15 minute slider and picks the highest kW usage. It's not random.

Any additional load that could kick up the "peak" is bad. That's why it's called a "peak" plan.
--
If someone refers to herself / himself as a "guru", they probably aren't.



PSWired

join:2006-03-26
Annapolis, MD

That doesn't make sense to me. What's the sampling interval? Highest 15-minute load to me means 15 minute sampling interval and they pick the highest of them.



hipwr

@myvzw.com

Demand charge calculations seem to vary a little from utility to utility. On my utility in rural MS, they calculate demand using a 30 minute interval with 5 minute rolling blocks which yields 6 sampling periods in a 30 minute interval. Picture the slider nunya See Profile mentioned advancing every 5 minutes. With each advance, one 5 minute block drops off and the current one is added to the average. Demand is calculated by adding the registered demand of each 5 minute interval and dividing the result by 6. For instance, if 10Kw is recorded in one block with each of the next five blocks only recording 1 Kw. You'd end up with (10+1+1+1+1+1)/6 or 2.5Kw billing demand. It's up to the utility and the state PUC which method and timing is used.



John97
Over The Hills And Far Away
Premium
join:2000-11-14
Spring Hill, FL
kudos:1
Reviews:
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reply to Jack_in_VA

said by Jack_in_VA:

Are you planning on pumping the same amount of GPM? A 1 hp load (746 watts) is the same regardless of what is supplying the power to it. Of course if the speed and capacity is reduced then there would be a savings.

No.
--
So put me on a highway, and show me a sign.
And take it to the limit one more time...

laserfan

join:2005-01-14
Texas
reply to scooper

said by scooper:

the more I verbalize this - the more it would just make more sense to just set the pool pump timer so it wouldn't come on during peak times and manually turn on pump when I want to swim (after setting the heatpump to not turn on while swimming). After all - the heat from the sun would still collect on the sunny part of the pool.

You figured this out on your own. This is the best and easiest answer to your problem.

As brand-new pool owners some years ago now, we let the installation company set-up our timer to run the pool some 6-8 hours every day. We've long since learned that at least for our setup we can run the pool pumps manually, for a couple hours a day (we turn it on before we're about to use it and then Off after) and are able to still keep the water crystal clear in doing so.

Of course YMMV but your basic answer is "just leave it off during peak elec usage times".

scooper

join:2000-07-11
Youngsville, NC
kudos:2
reply to scooper

Good news on the heatpump - a contactor had burned the points on one side - $150 later and we're back in business. So much better than having to buy a new heatpump system.... It was my basic suspicion, and I'm glad that's all it was.

Question - what are the effects of ANTS on heat pump / AC outside units ? I'm thinking they could get into contactor,s etc.



54067323

join:2012-09-25
Tuscaloosa, AL

said by scooper:

Question - what are the effects of ANTS on heat pump / AC outside units ? I'm thinking they could get into contactor,s etc.

You want them out of there period.

They do no good.