I was watching the Dirty Jobs show with Mike Rowe the other day. He was helping well drillers sink wells for a heat pump system for something like an old folks home. It occurred to me that I haven't heard of any for plain houses. Too expensive? By the way he can sing.
Plenty out there. "Geothermal heat pump".
Problem is much higher upfront cost than traditional air to air for cooling, and a hefty chunk more than for natural gas or oil for heating.
I know two people that looked into it for houses they were building. Initial cost was the deciding factor for them. Don't know enough about the specifics and payback time.
There is a video of Mike explaining how he got into the business using opera to get a union card.
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We put in ground loop geothermal system in the house in TN to replace the original air-exchange heat pump. Not a well, but 7-8 ft trench with heat transfer loop tubing at bottom and about halfway.
NG not available and didn't want the big tank. With a thermal switch to ensure the aux electric heat didn't come on unless outside temp <20 F, it had great performance and payback compared to the older heat pump about 4 years.
That was retrofit so excavation costs were a fair amount more than would have been if had done when doing the excavations for basement and septic when the house was built.
I'm sold on concept...
Ours was Water Furnace brand/manufacturer. We were there 7-8 years after doing it and now been back to farm 20 years. Last I knew, it was still going strong although that's about 3 years now since we stopped in and met the folks after the folks after the folks we sold to.
We didn't do it because the layout inside the house wasn't amenable, but one can get much cheaper hot water during cooling season from the exit side waste heat as an additional payback mechanism.
Yes they do.
That’s certainly the reason that they arent common.
All-The-Rage here about 15 years ago - not the well-type as much as the ground loop. My neighbour had a system installed on 2 sides < side and back > of his ~ 3/4 acre lot. At that time the cost was about 20 grand but the government rebates would kick you back about 6 grand. helping greatly with the pay-back time. They work great 3 seasons here in Southern Ontario but the cold months require auxilliary heat. John T.
An old high school friend (Dave Hatherton) was one of the brains behind "water Furnace". His family was in the well drilling business (Hadco Well Drilling in Elmira Ontario)
He's done a LOT of business in Ontario and beyond - including a lot of residential sysetems
A lot of Water Fuenace installs here require aux heat only about 15 days a year for an "average" central Ontario winter. Last winter was a bit of an exception with several long stretches below -20C
I've been to a house in Dover, Del. with geothermal heating and cooling. Not a cheap h ouse but no mansion either. T hey seem to have removed two new AC compressors in the process of installing the geothermal.
I didn't see how evacuated tube panels worked by looking at pictures. It seemed like the tubes should've been connected in series with water running through them instead of parallel like they are. This guy gave a good explanation:
My housing development down here in south Mississippi is new, with everything either built last year or this year. Each house has the ground loop that you described. Down here, it almost never gets down to freezing, so the systems seem to work pretty well.
I have other concerns/complaints about the HVAC system in my house, but the heat pump aspect of it seems to be fine.
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Good on him...I've not looked since as we've got NG on farm from a tap off the main pipeline out in the pasture, but they built a quality product.
The local contractor who had franchise in E TN had done a lot of them down on the lakefront with the lake as the heat sink/source; ours was the first ground loop he had done.
That's been 30+ year ago now, incredibly it seems impossible to have been back on the farm 20 years already...
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You don't have the noisy outside compressors any more...one of the real pluses...unless the heat sink isn't sufficiently large like the heat source not sufficient to require aux heat.
I would think that in Mississippi it would be the oppsite. YOu do not need to worry too much about heating, but more so with cooling and humidity control. So better to have the coils in the cooler earth than in the much hotter air.
I often see and understand how the efficiency of the heat pumps go down when it gets cold and you need auxillary heat. I have never seen any refference as to how to get extra cooling from the normal air installed heat pumps. I am sure the gound loop system would be much more efficent than the air system even in hot weather.
We've done a lot on commercial buildings where I work in Virginia, none on residential.
Results have been good BUT if you don't install perfectly it's really hard to troubleshoot or fix. High quality installation is more critical here than on most systems I've run into.
Most of ours are well type systems because of space. Oh, and if you aren't careful to keep all the trash out including deburring PVC, expect to be cleaning strainers for months.
Air-exchange heat pumps are just conventional A/C units when reverse valves for A/C.
And of course it's much less efficient to discharge the waste heat from the A/C when ambient is 100F, just as it is harder to extract heat from <40 F air for heating.
The geothermal source/sink is much more nearly stable and if properly sized can handle both cycles. With ours, the aux heat controls by default would kick on with a >3 F setpoint mismatch to provide more rapid warmup after an overnight setback in the morning, but we included a cutout to prevent them from kicking on unless outside <20F and never missed them.
The geothermal systems also can be set up to use waste heat on cooling cycle as preheat for hot water that can cut that cost down noticeably in cooling season as well. That's better in warmer climates, obviously.
My office is in a building with water source heat pumps for each area.
There is a water loop for the whole building. That loop includes a cooling tower and a boiler. Then there are 20 or so individual water source heat pumps for the office areas that exchange heat with the water loop.
This type setup is new to me but the energy savings have been larger than we expected, and reliability is high. There is no outside chiller needed at all.
Heat pump compressors ARE AC compressors - the sycle is just reversed for heating. Matter of a rather simple valve
Make good pool heaters too - --
I don't know if they were AC or heatpump. We talked a lot more about the geothermal than what had been removed.
I actually needed a new compressor and thought about renting a truck and bringing it backto Baltimore. I wish I'd checked further if it would have worked. If so, I would have saved a bunch of money. (the cmpressor was free to me.)
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