# Energy Efficient Residential Shallow Well Pump - solutions?



## phil san (Feb 12, 2010)

Have a Flotec shallow well Jet pump encased in an outdoor pit connected to a basement pressure tank. Pump is 115 VAC or 240 VAC currentely set to 115 VAC.
Pressure and pump are fine.

Trying to save energy since I use it for lawn/garden watering as well as household needs.  Having difficulty finding a more energy efficient pump or possibly a 12 vdc transformer from stepdown 115 VAC.  Anyone know of any?  All I seem to find are for an RV or can be connected to solar. Their pressure rating seem adequate and $ reasonable.


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## pybyr (Feb 12, 2010)

I've seen off-grid people use piston pump well pumps- of the sort that used to be used in homes before the advent of jet pumps.  They're fitted with DC motors for that application, but this Canadian company still seems to make the 'classic' one for on-grid use- 

in iron:
http://www.pompco.com/default.aspx?idPage=13
or
in stainless:
http://www.pompco.com/default.aspx?idPage=14


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## LLigetfa (Feb 12, 2010)

A cycle stop valve would save energy.

http://www.cyclestopvalves.com/


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## phil san (Feb 12, 2010)

I do have a cycle stop valve installed.  In my opinion, it saves wear and tear on the pump more so than electricity. Maybe the product I'm looking for is not available. I want something i.e. that runs off a say 12 v transformer pluggd into 115 VAC, such as some pellet stove blowers are made.  Now that would be a great electricity saving if I ran the water sprinklers for hours.


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## Gooserider (Feb 16, 2010)

phil san said:
			
		

> I do have a cycle stop valve installed.  In my opinion, it saves wear and tear on the pump more so than electricity. Maybe the product I'm looking for is not available. I want something i.e. that runs off a say 12 v transformer pluggd into 115 VAC, such as some pellet stove blowers are made.  Now that would be a great electricity saving if I ran the water sprinklers for hours.



Not sure I see how going to a 12v pump is going to save you electricity, unless its a smaller pump...  To move a given amount of water at a given pressure, takes the same amount of power regardless of what form the power takes - with the possible caveat that a given motor be slightly more efficient, making more HP for a given amount of power input, but this is generally pretty minor.  Put the losses of the transformer on top of that, and I don't see how a DC pump will save you anything...    My understanding is that the reason the off-grid people prefer the DC units is that it allows them to run directly from the panels / batteries, and thus saves the losses of making 110AC power.  It is NOT because the pumps themselves are less efficient - Volts x Amps = watts, and if you need a given number of watts and lower the voltage, you increase the amps, and vice versa...

Gooserider


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## RobC (Feb 16, 2010)

Pumping water at volume and pressure requires horse power. No getting away from it like Goose said. If you were to change your watering equipment from sprinklers that require pressure to operate to drip irrigation you might have a solution. Some drip requires very little pressure. 
If you had a plastic storage tank on a slight hill above area to be watered, and a 12V pump run off a solar panel. You could pump from well up to storage tank and then water down hill from there. 
You really need to look at your demand for irrigation Gallons Per Day and flow charts for pipes, pumps and storage tank etc. 
Companies like Toro, Rain Bird, Netifim make drip equipment.
The only other way to save is to adjust your existing pump cut out pressure down a little, there by saving some electricity in the shut off stage of your pump cycle. 
Rob


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## LLigetfa (Feb 17, 2010)

Generally speaking, higher voltage means lower current and less loss to heat.


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## oldspark (Feb 18, 2010)

LLigetfa said:
			
		

> Generally speaking, higher voltage means lower current and less loss to heat.



As long as the resistance changes with the higher voltage because I=e/r.


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## Gooserider (Feb 18, 2010)

oldspark said:
			
		

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True for the entire circuit, but for the wiring, LL has it - if you take the same wiring, and run higher voltage through it, with a load that does the same amount of work (i.e. consumes the same amount of power) then the current in the wire will be less, and the amount of voltage / heat dropped across the wire will be less - i.e. a dual voltage motor being run on 110V vs. the same motor running on 220V The power / wattage will be the same, but the motor will draw fewer amps at 220V - with the result that it will run cooler, and allow the use of longer / lighter gauge wires.

To produce a given amount of work will take the same amount of power (assuming equal power use efficiency) and since W=IxE, the higher the E, the lower the I.  For a given size of wire, which will have a measurable amount of resistance, the lower the I, the less heat will be dissipated in conduction losses.  This can allow the use of lighter wiring in some cases, while keeping the electrical loss to an acceptable level.

This is also why high electrical load vehicles (large trucks, tractors, etc.) tend to be 24V or higher, rather than 12V as it cuts down on the size and weight of the electrical parts required. 

Gooserider


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## JustWood (Feb 18, 2010)

Collect water off roof in rain barrels or tank=no electric. You'd be surprised how much better your garden will like warm rain water instead of cold ground water.


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## oldspark (Feb 18, 2010)

Gooserider said:
			
		

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Very true, I was just pointing out that some times people get it turned around and think the amps get dropped with higher voltage automaticly, if all things are correct and you do not have a long run you do not lose much on a 110 motor vs a 220, but as you pointed out you can use smaller wire which for some applications is needed.


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## Gooserider (Feb 18, 2010)

oldspark said:
			
		

> Gooserider said:
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The reason you don't lose much on a 110 motor, or other loads, is because the electrical codes have strict requirements for wire sizing that are intended to keep the loss to a tolerable level (1% if I recall correctly) 

The amperage draw does go down sort of "automatically" with increasing voltage simply because the loads pretty much HAVE to change in order to deal with the different voltages, which increases their resistance, etc...  Even when you have a load that allows connecting to different voltages (like a power supply) there will be internal circuitry that changes it's electrical characteristics...

Gooserider


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## oldspark (Feb 18, 2010)

My point exactly, been an electrician for over 20 years and can not count the number of times people have got this wrong and still run in to it once in a while, In fact some times you can not get them to understand it.


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