DIY Ground Source Heat Pump

Post image for DIY Ground Source Heat Pump

by Tim Fulton on August 18, 2009

For a while now, one of our forum members, AC Hacker has been working on a DIY solution for a ground source heat pump, or what he likes to call his Homemade Heat Pump Manifesto. Yes, a DIY solution for those incredibly efficient and incredibly pricey heating and cooling systems. He has been making some great progress, so I thought it would be a good thing to share with our blog readers that don’t always make it over to the forums.

AC Hacker started out making the smaller prototype unit (pictured above) to see if it was all possible.  This small unit actually turned out to be pretty efficient.  The initial calculations showed the prototype running over 400%.  Heat pumps are capable of exceeding 100% efficiency since you aren’t creating heat, you are simply moving it from one place to another.

With the prototype being a success,  he started planning for a full size system for his house.  He believes he can put an entire system together for under $2000!  Commercially installed systems start at $15,000 and go up from there.

There is a lot to this project, and we’ll be covering it as progress is made.  If you really want to jump into it you can check out AC Hacker’s forum thread here.


1 Tom Thompson October 19, 2009 at 1:14 pm

I could give my home up for testing. It is here in The hotest spot in the US PHOENIX, AZ. If it will work well here there should be a big market for it along side of a solar install!!!!!!

2 jonion December 1, 2010 at 10:09 am

Very interesting. I have been considering a similar project possibly using a used window AC unit to build a water-water heat pump to boost the temperature of my solar heated domestic water. Comments?

Any particular challenges in adapting the ac unit to this purpose?

3 Tim Fulton December 1, 2010 at 1:40 pm

I would suggest taking your comments to the forum. You’ll likely get much interest & replies there.

4 Greg Stamler July 22, 2011 at 10:31 pm

Very interesting.
Think I will start digging the hole by hand
in my basement this winter.
Lord knows I need the exercise !!

5 Jeff November 26, 2011 at 7:12 pm

Hi, I know your system is ground sourced, but I have a question about air sourced systems. I hope you can help. Since they get heat from the air, would it be better to install the outdoor unit inside something like a greenhouse? It would be protected from the elements and inside the greenhouse should be the same temp as outdoors (at night), and sunlight would provide heat for it to pump. Does this sound reasonable? Thanks for your help.

6 Rev. Leslie Allen Stelter September 23, 2014 at 11:05 pm

I want to insulate a wood burning chamber so the wood burns at 1800 degrees. Then I want the hot gases to enter a much larger insulated chamber, which I will call a heat storage box. Since the higher the temperature the more efficient a heat pump will work at. So my heat box will be 20 times larger than the insulated wood burning chamber. I want to put about 80 feet of 3/4 inch copper pipe in the heat storage box. I want to use a radient heating pump to pump the heated antifreeze to a heat excanger finned in the house to release the heat into the air. I want to line the heat storage box with concrete fiber board and control its temperature at about 180 degrees. Will a standard heat pump work in this temperature? Could I use 40 feet of copper pipe instead. I could make the walls of the heat box out of the same stuff I made for the burning chamber: vermiculite and portland cement and lime. They make a 2 inch wall that hold up the fire bricks. If I burn wood so I make 80,000 BTU’s of heat for the heat box, how long will it take the DIY heat pump to transfer it to the finned auter to air heat exchanger in the house? The exhaust gasses will leave the heat storage box at about 70 degrees at the far end. I want to burn wood this way at 98 percent efficiency. Fr. Les I will use two squirrel cage fans to burn wood, and pull the exhagust gases out of the heat storage box.

7 Rev. Leslie Allen Stelter September 23, 2014 at 11:13 pm

After burning 80000 btu’s of wood I want to store it in an insulated heat box and bring the temperature down to 180 degrees. Can heat pumps work in this high heat? The hotter it is, the more efficient the heat pump is. How long will a heat pump need to move this amount of heat? I will use a water to air heat exchanger in the house. Fr. Les The heat box will be fully insulated.

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