The Homemade Heat Pump Manifesto

DonT · 02-21-16, 12:42 PM

I’ve been reading this Manifesto for the past several weeks and I’m on page 58, (I’m a slow reader LOL). I’m thinking about putting in a GSHP this summer.
I’m a contractor doing new construction and remodels etc. so I know a couple of the HVAC, plumber, etc. I can do plumbing and electrical myself.
A bit about my current setup. I live on the MN-IA state line near I35, so my temperature are -30 in the winter to 100 in the summer. My home is build inside of a machine shed on an acreage. The machine shed is 64 x 42 with 16ft sidewalls. I built my loft in the back, 7ft off the ground. Its 18ft x 42ft with an entry 9ft x 12ft so total sq ft is about 864. I have ½ pex tubing hanging 3in down from the subfloor (that was a lot of holes to drill). I have a utility room on the ground floor that’s 12ft x 18ft cement slab with ½ pex tubing. I heat this entire area with a 6000w 10 gallon electric hot water heater, not a boiler. The water temp is set at about 175 deg. For the month of January it cost me $4.95 per day for my heat and hot water (potable). I do NOT have AC. I rig up a window AC that kind works.
So, 1st off would I save enough to make the GSHP pay off? It would add AC so that’s why I‘m thinking about doing it
I have a new 11350 btu R22 compressor a friend gave me, never used.
A friend has a mini-excavator I can rent for $100, so I can trenching in a ground loop about 8 to 10 feet deep.
My nephew works at a place that make stainless steel tanks and he can make my water tanks for me.
What I need to know is how much and what size copper tubing I need to make the Freon to water heat exchanger tanks.
For the ground loop, 1st HVAC guy said I need 300 ft per ton ground loop, the 2nd said 500 ft and the 3rd said 800 ft. So somewhere between 300 and 800 ft, big difference. I would like to narrow that down a bit.
So the big questions are the heat exchangers and the ground loop.
This is just the beginning of a lot of questions.
Don

02-21-16, 12:42 PM	#10
DonT Lurking Renovator Join Date: Feb 2016 Location: Northwood, Iowa Posts: 27 Thanks: 2 Thanked 5 Times in 5 Posts	I’ve been reading this Manifesto for the past several weeks and I’m on page 58, (I’m a slow reader LOL). I’m thinking about putting in a GSHP this summer. I’m a contractor doing new construction and remodels etc. so I know a couple of the HVAC, plumber, etc. I can do plumbing and electrical myself. A bit about my current setup. I live on the MN-IA state line near I35, so my temperature are -30 in the winter to 100 in the summer. My home is build inside of a machine shed on an acreage. The machine shed is 64 x 42 with 16ft sidewalls. I built my loft in the back, 7ft off the ground. Its 18ft x 42ft with an entry 9ft x 12ft so total sq ft is about 864. I have ½ pex tubing hanging 3in down from the subfloor (that was a lot of holes to drill). I have a utility room on the ground floor that’s 12ft x 18ft cement slab with ½ pex tubing. I heat this entire area with a 6000w 10 gallon electric hot water heater, not a boiler. The water temp is set at about 175 deg. For the month of January it cost me $4.95 per day for my heat and hot water (potable). I do NOT have AC. I rig up a window AC that kind works. So, 1st off would I save enough to make the GSHP pay off? It would add AC so that’s why I‘m thinking about doing it I have a new 11350 btu R22 compressor a friend gave me, never used. A friend has a mini-excavator I can rent for $100, so I can trenching in a ground loop about 8 to 10 feet deep. My nephew works at a place that make stainless steel tanks and he can make my water tanks for me. What I need to know is how much and what size copper tubing I need to make the Freon to water heat exchanger tanks. For the ground loop, 1st HVAC guy said I need 300 ft per ton ground loop, the 2nd said 500 ft and the 3rd said 800 ft. So somewhere between 300 and 800 ft, big difference. I would like to narrow that down a bit. So the big questions are the heat exchangers and the ground loop. This is just the beginning of a lot of questions. Don