Can a hole in my garage floor keep it warm in winter (geothermal heat)?

[KeithS]

If I was to bore a 4" or even 6" diameter hole into my garage floor drain and install a PVC pipe to a depth of 10 feet would the geothermal heat keep my garage warmer? I live in Northern Michigan and frost can reach depths of 7' or more. I am not looking to sweat in there, but could it allow some heat up, or would the colder temperatures overtake the grounds ability to transfer the heat? Thanks!

 

[berkeman]

and install a PVC pipe to a depth of 10"

10 inches or 10 feet?

 

[KeithS]

10 inches or 10 feet?

Thank you for the catch! 10 Feet

 

[Andrew Mason]

Not unless you have air circulating down into the hole. Better to drill two holes joined at the bottom and circulate air down one and up the other. But unless you have the right kind of soil such that heat flow will occur continually from surrounding warmer parts to the parts around the hole, all you will be doing is allowing the ground 7-10 feet down around the hole to freeze.

Heat pumps would be a better option, but these will not be effective unless you can draw energy from a large underground reservoir. This can be done by an array of pipes running through the ground. They are expensive and don't really save ghgs unless you are using renewable source electricity.

AM

 

[KeithS]

Not unless you have air circulating down into the hole. Better to drill two holes joined at the bottom and circulate air down one and up the other. But unless you have the right kind of soil such that heat flow will occur continually from surrounding warmer parts to the parts around the hole, all you will be doing is allowing the ground 7-10 feet down around the hole to freeze.

Heat pumps would be a better option, but these will not be effective unless you can draw energy from a large underground reservoir. This can be done by an array of pipes running through the ground. They are expensive and don't really save ghgs unless you are using renewable source electricity.

AM

Thank you, I was hoping to just take the bite out of the air, but it sounds a little more involved than my wishful thinking! :)

 

[Baluncore]

It is probable that the air in the garage is stratified, with cold air on the floor and warmest air up above your head.
Do a survey by measuring the outside air temperature and the temperature at various levels in the garage. It may be worth slowly venting the lowest stagnant air from the garage and replacing it with warmer external air.

 

[cjl]

Not unless you have air circulating down into the hole. Better to drill two holes joined at the bottom and circulate air down one and up the other. But unless you have the right kind of soil such that heat flow will occur continually from surrounding warmer parts to the parts around the hole, all you will be doing is allowing the ground 7-10 feet down around the hole to freeze.

Heat pumps would be a better option, but these will not be effective unless you can draw energy from a large underground reservoir. This can be done by an array of pipes running through the ground. They are expensive and don't really save ghgs unless you are using renewable source electricity.

AM

Modern heat pumps actually save GHGs even if powered by a pure natural gas generator. On a typical US grid mix, they are substantially lower emission than even a 97% ultra high efficiency gas furnace. If your local grid is almost entirely coal, you're probably better off with the furnace, but otherwise the heat pump is the way to go (even air source heat pumps, though ground source as you describe are more efficient). The heat pump also has the benefit that its emissions drop as the grid gets cleaner, so assuming you think the grid will continue trending in that direction, the lifecycle emissions will be even better than the current comparison would indicate (while a gas furnace will, of course, always be burning gas).

 

[Rive]

would the geothermal heat keep my garage warmer?

Unless your garage is well insulated you won't likely to notice the difference.

 

[Andrew Mason]

Modern heat pumps actually save GHGs even if powered by a pure natural gas generator.

If the waste heat from the 25% efficient natural gas generator was used to heat the garage and the electricity generated was used to run a properly installed heat pump, then you will be saving energy and ghgs over a gas heater, regardless of temperature difference. I'm not sure about cost effectiveness, though.

AM

 

[Rive]

For this application an active heat pump would be an overkill. Look into thermosiphons instead.

Though I still think the available heat won't be enough.