Loop temps and BTU capacity?

[The master plan]

Well, I now have both of my underground loops up and running. Just testing for now and purging the air out of the lines. It looks ghetto but, hey its just a test rig right now. Loops run into the bucket to be pumped back into the ground again.



Its been a really mild winter here, so I'm sure the ground isn't frozen very deep. The MNDOT has a website that lists the depth of frost and it shows about 18" now.

My loops are 2 x 600ft of 3/4" slinky coil about 6ft under the ground and run under the garage slab and driveway. Right now I get about 42F...how does that fair?




Short term use will be as an "air conditioner" during the summer and later maybe add a heat pump to it if I can determine the loops are sized big enough. I plan to run the loop water threw a heating coil. Its rated at 120,000BTU with 180 water. I figure if the water temp is low enough this summer I can use a fan to blow across the coil to cool my garage or home this next summer.

[AC_Hacker]

Originally Posted by The master plan

My loops are 2 x 600ft of 3/4" slinky coil about 6ft under the ground and run under the garage slab and driveway. Right now I get about 42F...how does that fair?

Well, it's pretty darn chilly... but there is heat down there that a heat pump can pull out. You need to be careful because as you draw heat out, the ground temperature will slowly decline. If it gets too cold, you could freeze your HX solid and ruin it. If you run an antifreeze that is appropriate for GSHP use, you can go lower in temperature. How low depends on the % of antifreeze.

When water in the ground goes from liquid form to solid, quite a bit of heat can be extracted in that process.

Personally, I am going with the idea that I would rather stay above freezing and avoid the antifreeze issue.

Straight water has lower viscosity and higher heat carrying capacity. I like both of those ideas.

Originally Posted by The master plan

Short term use will be as an "air conditioner" during the summer and later maybe add a heat pump to it if I can determine the loops are sized big enough. I plan to run the loop water threw a heating coil. Its rated at 120,000BTU with 180 water. I figure if the water temp is low enough this summer I can use a fan to blow across the coil to cool my garage or home this next summer.

Great going on your project!

Using your loops for both heating and cooling is a great idea.

• When you use your loops for cooling, you will be storing heat in the ground during the summer... for use in the winter.
• When you use your loops for heating, you will be storing cool in the ground during the winter... for use in the summer.

No need to apologize about your setup for purging. My setup for the same process was way more 'getto'.

Regarding your plan to cool your shop, one of the frequent posters to the 'Manifesto' thread also tried the same idea. You'll probably want to see how it worked out for him.

Here is the link to the post.

You'll probably want to read some of his posts that follow that post also... he had a lot of good information.


And if you haven't already seen this thread, this guy in Florida (his forum name is 'rhino') is putting in a system very much like yours, for cooling only. I believe he is going with a commercial GSHP unit to connect to his loop field.

There's a lot of very interesting work going on!

Regards,

AC_Hacker

[rhino 660]

Originally Posted by AC_Hacker

And if you haven't already seen this thread, this guy in Florida (his forum name is 'rhino') is putting in a system very much like yours, for cooling only. I believe he is going with a commercial GSHP unit to connect to his loop field.

There's a lot of very interesting work going on!

Regards,

AC_Hacker

i forgot to add in my thread im doing heating and cooling now that im going with a nice heatpump and it is really cold here right now it diped into the 30's

[AC_Hacker]

Originally Posted by rhino 660

i forgot to add in my thread im doing heating and cooling now that im going with a nice heatpump and it is really cold here right now it diped into the 30's

Actually, that should help your A/C efficiency come summer, and the A/C use should help your heating come winter.

-AC_Hacker