The Homemade Heat Pump Manifesto

[mmech]

AC_Hacker and other contributors

Thanks for all the good info. I just finished reading p46 of the 193. Thanks for the link to the Geothermal Heat Pump Design Manual on that page. Lots of good info about the capabilities in different areas of the country. That is a big plus for me as I want to be in an area I can do eco-friendly projects and it be worthwhile without extreme costs.

Right now I'm just trying to learn about the stuff to be better informed when I do take on the projects.

[Rebuilder]

OMG! What an epic thread!
Thank you so much AC for your unbelievable commitment to this thread. I've never seen anything like that in any other forum.
I'm so eager to start my home made heatpump projects. I have tons(pun intended) of donor projects to choose from(a bit of a hoarder). First I think I'll try getting some heat going in my tool shed and barn after I do some "insulate, insulate, insulate".

[AC_Hacker]

Originally Posted by Rebuilder

OMG! What an epic thread!
Thank you so much AC for your unbelievable commitment to this thread. I've never seen anything like that in any other forum.
I'm so eager to start my home made heatpump projects. I have tons(pun intended) of donor projects to choose from(a bit of a hoarder). First I think I'll try getting some heat going in my tool shed and barn after I do some "insulate, insulate, insulate".

Rebuilder,

It takes a dedicated person to read through the thread. Congratulations!

You are correct to minimize heat loss (minimize infiltration & maximize insulation). When you feel that you have done what you can do, then take a look at what would be required to heat your structure(s). At that point, your heat loss will be smaller, so your heat pump that will do the heating will be smaller and easier and cheaper to build.

Good luck, keep us posted, and remember, we love photographs of projects.

Best,

-AC_Hacker

[Roostre]

It took me a long time, but it's done. Whew.

What a great thread and resource for the DIY experimenters out there.

I found that the "Closed-Loop/Ground-Source Heat Pump Systems - Installation Guide" can be found for a bit less and ordered a copy. It is from 1988 so I hope it's not too outdated.

The section on Heating and Cooling Degree Days led me to develop this chart based on a local weather station:


My heating bill from January of 2017 shows it to be an exceptionally cold month. By back calculating the Therms it looks like the house required about 25,000 BTU/hr to maintain.

The loop is going to be the most challenging aspect I can foresee; after researching local laws it turns out that you cannot drill deeper than 30 feet without a permit from the state AND you must be a certified driller.

For a horizontal loop install we do have a decent sized backyard at about 100 feet deep and 110 feet wide. The "installation Manual" should be of great help here.

I plan to make a fusion tool fashioned after your design and spend a good deal of time practicing until my joints are 100% solid.

Thanks again for this manifesto. It excites me that such leverage exists to be harnessed by all with a little education and effort.

[AC_Hacker]

Originally Posted by Roostre

It took me a long time, but it's done. Whew.

What a great thread and resource for the DIY experimenters out there.

I found that the "Closed-Loop/Ground-Source Heat Pump Systems - Installation Guide" can be found for a bit less and ordered a copy. It is from 1988 so I hope it's not too outdated.

The section on Heating and Cooling Degree Days led me to develop this chart based on a local weather station:
Attachment 8156

My heating bill from January of 2017 shows it to be an exceptionally cold month. By back calculating the Therms it looks like the house required about 25,000 BTU/hr to maintain.

The loop is going to be the most challenging aspect I can foresee; after researching local laws it turns out that you cannot drill deeper than 30 feet without a permit from the state AND you must be a certified driller.

For a horizontal loop install we do have a decent sized backyard at about 100 feet deep and 110 feet wide. The "installation Manual" should be of great help here.

I plan to make a fusion tool fashioned after your design and spend a good deal of time practicing until my joints are 100% solid.

Thanks again for this manifesto. It excites me that such leverage exists to be harnessed by all with a little education and effort.

Glad you want to get your project going. before you begin your loop, you should try to find out everything you can about soil conditions. Ask local well drillers and ask local GSHP installers. It really helps to know what's down there before you begin.

My lot size is very small, so I could only drill down. Sounds like you have more property and trenches would be easier to do. After I did mine I happened to look at the cost to rent equipment for digging serious trenches, and it was not so bad.

Also consider what the frost line is in your area, very important.

Vlad built an amazing drilling machine that totally kicked ***. If you think you might want to do this, I can give you some general information. Vlad is a very unusual guy with lots of skills. He drilled 50 foot holes I believe.

Renting a back hoe is way easier.

Regarding my pipe fusing tool, it worked very well. I used it to weld 'butt joints', where two molten pipe faces are welded directly together. A little practice and experimentation is called for. I would caution you that in my method, I made all of my 'U-Turns" at the bottom of the hole with three butt welds each. I had sixteen holes, plus a few extra welds. All together that was a lot of welds. Each weld had a bit of 'roll' inside the pipe, which causes some amount of friction. If you over-heat the pipe face, and use lots of pressure holding the two pipe faces together, the roll will be bigger (more friction). However if you practice and get just the right amount of heat & pressure you can make a good weld with very little roll. I did some testing and calculating on my loop, and the large number of butt welds cost me some friction loss.

If you go for trenches, you will not encounter very many welds, so a smaller number of butt welds won't make much difference in friction.

There is also another system called "Socket Welding". If you check it out, it leaves no rolled HDPE inside the pipe.

Vlad bought a socket welder from ebay, and it worked for him. I borrowed it and discovered that the Heating Sockets, which are coated with Teflon, would fit and function perfectly on my little home made paddle. The cost of a pair of those sockets was not too much. Might want to look into that. Maybe rent one local. I did check out rental, and was offended by the price, so I built my paddle-welder instead. I found out about socket welding after the fact. The butt welds are very strong, the equipment is cheaper. Your choice.

If you can tell me your Zip Code and the beginning and end of your worst heating month, and the therms used in that billing period, I will double check your numbers... couldn't hurt.

By the way, Ecorenovator "randen" dug trenches for his very successful system. He is probably watching this thread, but if he doesn't weigh in, please contact him, he has much GSHP lore to share. He built two heat pumps, one was fairly easy, it was 2.5 Tons, the other was three-phase and 3-Tons. He had problems on the second one, in part because a pre-used compressor failed.

Good luck on your project, you will have much support here.

Photographs of your undertaking always helps.

Best,

-AC_Hacker

[pr0cess0r]

Hello, i did not read all the thread yet but im very impressed with all information there is in it. Thank you for sharing.

Im wondering did you ever thinked about using pool heat pump has a starting point for your project. curently im fixing one to heat my pool it have a vracked heat exchanger that im patching.

When fixing it looked how everything is working ans this machine have those sensor
outside air temp (groud loop water temp)
inlet water temp (hot water tank temp)
outlet temp(water temp returned to hot water tank)
water flow that can be used to make sure the unit only run when water pump work

it also use a 3 wire control start is standard and im sure its possible to use themostart or other deives to talk to this protocol.

also its made for cooling and heating alredy and alredy have one side setup for water.

my unit is 50 000 btu it mean it would take less time to heat the water not take more power.

Anyways i whas just wondering if this could make less problem to solve when building a new systeme.

Thak you for all your detail about A/C equipment maybe i will be able to extract r410 myself when replacing my heat exchanger if epoxy path dont hold to pressur heat and chemicals.

[mejunkhound]

epoxy path dont hold to pressur heat and chemicals

wow, if you find and epoxy that will hold 410 apllied on external surfaces. let us in on the details of the type AND specific application procedure.
Even initially but especiall after a few months.

Would recommend 15% silphos if you cannot find an epoxy that works. Every DIY needs at least an oxy-propane setup

[pr0cess0r]

Originally Posted by mejunkhound

epoxy path dont hold to pressur heat and chemicals

wow, if you find and epoxy that will hold 410 apllied on external surfaces. let us in on the details of the type AND specific application procedure.
Even initially but especiall after a few months.

Would recommend 15% silphos if you cannot find an epoxy that works. Every DIY needs at least an oxy-propane setup

No its the water part that i fix made of pvc. Only one epoxy really work anything quick fail it need to be 24h curing. I tryed normal j-b weld and it failed and plastic j-b weld it also fail.

[dark84]

Hi!
Sorry for bad english.
I am from europe ( Serbia).
I have outdoor unit R22 18000btu.
I want to create air-water heat pump from this unit.
I want to use it for heating and cooling.
I have a copper tube 8mm and 30m lenght.
And have a tank of 125 litres. First variation is that i made a heat exchanger coil from tube in tank. How i do this? Its good that i make a spiral from copper tube and put in a tank?
If this not good i have a heat exchanger Alfa Laval CB52-22HX. I know that this exchanger is large, but i able to use it for 18000btu outside unit? And the last thing is i have a friend who repairs a refrigitation systems. He tells me that for that compressor (rotary) wich is in outside unit i must use just cappilary tube (wich is in outside unit) as metering device, because the txv will decrease a flow in system and this compressor don't tolerete that. Thanks for help, and again sorry because my bad english.

[mejunkhound]

made a tube in tube water to R22 exchanger

36mm inside diameter PVC plastic pipe carries water

Inside the PVC pipe have 18 mm diameter coper pipe with R22 inside.

25 meters length = 60,000 BTU/hr ( 17 kW)

for your 18,000 btu, 10 meters of tube in tube water to R22 is good for the evaporator.

my use is heat pump only, water to air, the tube in tube described may not work as well as condenser.