tom.andersen
Software programmer
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- Location
- Meaford, Ontario, Canada
- Website
- www.ironicsoftware.com
I just installed a whole house energy monitor, and was surprised by the fact that my 1/2 hp franklin well pump uses 1400 watts. I never thought that the well pump would use so much electricity. 1/2 hp is after all only 746/2 watts. I guess the 1/2 hp is the 'output hp' of the pump, and it is ~25% overall efficiency?
It would not be a big deal, except that I am on an open loop geothermal system. I have read a few posts in here - great info - and I know that this is not ideal, but here is my system:
80 ft well, water level is about 40 ft down, lots of water. Some calcium in it - but I don't think that that is an issue, as over 90% of the load on the GSW 036 heat pump is heating our heated floors. I think that mineral release only occurs if you heat water up. I take in water at 11 C and dump it at 4 C. This is about the minimum water that I can get the heat pump to work with, any less and the freezing protection will trip in the heat pump. I change the floor water temperature a few times through the heating season to maximize efficiency (90 - 105F). The drain for the heat pump just goes into a wet field via buried big - o. (so no possibility to benefit from siphon effect for geothermal drain).
When the heat pump is operating, the well pump cycles at about 50% duty load, into a very large pressure tank here in the house. The water pressure is at 45 psi. The heat pump likely runs over 70% of the time from Nov 15 - Feb 15. I use my wood stove on cold nights, instead of letting backup kick in.
So after reading some posts in here: I come to the conclusion that I can reduce my electrical demand by lowering the water pressure in the house (not gonna pass), or - what I think is perhaps a doable plan - lower the pressure in the large pressure tank to ~20 psi, then have a small pump drive the house plumbing off of the 20 psi system.
1) Its bad for a pump to cycle. Mine runs for 5 min on then 5 min off. Perhaps this is OK? Its not cycling every 10 seconds. Its been cycling for 4 years now. (say 5 to 6 months/year like that)
2) Is 1.4 kW really the amount of electricity for a 1/2 hp pump driving up 40ft then into a 45 psi tank?
3) Are there any problems with having a separate pump in the house for domestic water? What is a really quiet dependable pump (two showers, 3 kids, not much lawn watering).
In the summer, I cool by making cold water with the water to water heat pump, then drive the cold water up to 3 'multiaqua' heads in the highest places in the house. Works fine.
I include a photo of energy use this morning - you can see the heat pump turn on 3 and half times, and the 1.4 kw well pump are the 3 ish bumps on top of each heat pump cycle. Its 5C outside, so its not running at full tilt today.
Thanks for any thoughts.
--Tom
It would not be a big deal, except that I am on an open loop geothermal system. I have read a few posts in here - great info - and I know that this is not ideal, but here is my system:
80 ft well, water level is about 40 ft down, lots of water. Some calcium in it - but I don't think that that is an issue, as over 90% of the load on the GSW 036 heat pump is heating our heated floors. I think that mineral release only occurs if you heat water up. I take in water at 11 C and dump it at 4 C. This is about the minimum water that I can get the heat pump to work with, any less and the freezing protection will trip in the heat pump. I change the floor water temperature a few times through the heating season to maximize efficiency (90 - 105F). The drain for the heat pump just goes into a wet field via buried big - o. (so no possibility to benefit from siphon effect for geothermal drain).
When the heat pump is operating, the well pump cycles at about 50% duty load, into a very large pressure tank here in the house. The water pressure is at 45 psi. The heat pump likely runs over 70% of the time from Nov 15 - Feb 15. I use my wood stove on cold nights, instead of letting backup kick in.
So after reading some posts in here: I come to the conclusion that I can reduce my electrical demand by lowering the water pressure in the house (not gonna pass), or - what I think is perhaps a doable plan - lower the pressure in the large pressure tank to ~20 psi, then have a small pump drive the house plumbing off of the 20 psi system.
1) Its bad for a pump to cycle. Mine runs for 5 min on then 5 min off. Perhaps this is OK? Its not cycling every 10 seconds. Its been cycling for 4 years now. (say 5 to 6 months/year like that)
2) Is 1.4 kW really the amount of electricity for a 1/2 hp pump driving up 40ft then into a 45 psi tank?
3) Are there any problems with having a separate pump in the house for domestic water? What is a really quiet dependable pump (two showers, 3 kids, not much lawn watering).
In the summer, I cool by making cold water with the water to water heat pump, then drive the cold water up to 3 'multiaqua' heads in the highest places in the house. Works fine.
I include a photo of energy use this morning - you can see the heat pump turn on 3 and half times, and the 1.4 kw well pump are the 3 ish bumps on top of each heat pump cycle. Its 5C outside, so its not running at full tilt today.
Thanks for any thoughts.
--Tom
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