The Homemade Heat Pump Manifesto

[Ko_deZ]

Hi all.

Back with good news. That B3-32 unit is pretty much exactly what I ordered from this chinese factory. They take small orders, produce to specs (I did spec everything, from number of plates to sizes of connectors, where I did as I always do, oversized everything quite a bit, just to be sure). Prize was less than half of dudadiesel, and for what I can see, the units are really good quality. I got five of them, four gas->water and one water->water. Will be using these for different projects of course, but compared to local prizes here, I got 5 for half the prize of one. You guys have a better local prize, but you cannot beat these guys.

Anyway, it is very late here. I will get some pictures tomorrow if I can manage. There is a million projects going on around the house, making it winter ready, and my family is helping out, so I must prioritize this. Anyways, hold the HX orders for a little while, and you might save a bunch of money.

These 5 units weigh 21 kg btw. DHL sure had their work cut out.

Regarding the solutiong that RickReid (was that right) was looking at, getting cold from his well, this is how it is done here. No grout, and we use a normal plastic tubing like you use in slinkies and stuff. You can get high turbulence tubes that are corrugated inside to get higher efficiency. We just put it from top to bottom, U bend, and then back up, no fancy coil stuff. The longer the area, the more energy can be released/gained over long periods.
Would advice against a coil in the bottom. Also, depending on your geological situation, bottom of the well might be warmer than higher up due to heating from the magma below, radioactive rock (we have that here, gains a couple of degrees). Water is heaviest at 4C, so just above freezing, but the bottom is not always that temperature.
Also, why run it trough a heat pump? That water might be more than cold enough already. No reason to pump the compressor energy down into the well also, just run a direct heat exchanger on the water, then if you need more cooling, run the AC. As long as the water temperature is less than indoor, you will have "free" cooling energy.

[S-F]

Originally Posted by Ko_deZ

Hi all.
Also, why run it trough a heat pump? That water might be more than cold enough already. No reason to pump the compressor energy down into the well also, just run a direct heat exchanger on the water, then if you need more cooling, run the AC. As long as the water temperature is less than indoor, you will have "free" cooling energy.

People are doing that here but it only seems to work until the middle of the summer. After that the ground temp has risen to where it's no longer effective.

[AC_Hacker]

Originally Posted by S-F

People are doing that here but it only seems to work until the middle of the summer. After that the ground temp has risen to where it's no longer effective.

S-F,

Could you ask around to the folks who are doing this and find out what kind of loop field they are using?

I'd be very interested to know if they're using slinkys or boreholes.

-AC_Hacker

[S-F]

Where I live it's usually holes, but not always. Maybe 85% of the time. Just a guess. Apparently the cost of digging a trench deep enough rivals paying a well driller. It gets cold here so trenches need to be deep and the difference between digging a 6' trench and an 8' trench is apparently very very large. Also the cost of landscaping needs to be considered. If you tear up 1/2 acre for trenches you need to then deal with a torn up yard, which can be quite expensive if you aren't just throwing grass seed on the ground and hoping it will grow. I should also add that no special considerations for this method of cooling are taken when calculating the loop field. It's just a fringe benefit that some of the more thrifty and experienced HVAC guys use.

[Geo NR Gee]

Today the first borehole began for the ground loop. The Hydra-Drill fixture had some bent poles which stopped the drill from desending past halfway. After some odd size 1 3/8 O.D. pipes were acquired we were back at it. The drill made for a quick 15 feet, where it started jerking and bouncing. Had to stop for family issues.
The material that ended up in the first mud pit was mostly sandy material as pictured on the right. The material on the left of the picture is the material from the mud pit when it was made.

Tomorrow maybe if we start earlier, we can dig a little deeper.

Where do you get the fitting that goes on the bottom of the poly pipe at the bottom of the borehole?

[AC_Hacker]

Originally Posted by braebyrn

Today the first borehole began for the ground loop.

Very excellent news! I'm really excited for you and your loop field success.

Originally Posted by braebyrn

The drill made for a quick 15 feet, where it started jerking and bouncing.

Well, when mine did that jerking and bouncing thing, it meant that I had hit a rock. We may have very similar ground, you and I. You may be able to move your drill a few feet and try again with better success.

Originally Posted by braebyrn

Where do you get the fitting that goes on the bottom of the poly pipe at the bottom of the borehole?

Oh, you're talking about the "U-turn" aren't you?

No matter how tempting it may be to want to use brass or copper or steel, DO NOT DO IT! You want your entire loop filed to be plastic ALL THE WAY.

There are two methods that I know of...

One is to use socket fusion and to fuse two elbows. I have seen videos of this method, but I haven't done it, myself.

Socket Fusion for Geothermal - YouTube

The other way, is the way I did it... I have never heard of anyone else doing it the way I did it, but it worked.

Here's a link to the beginning posts of my homemade fusion tool. Here's a link to the final fusion paddle. Mine worked pretty well.

BTW, the paddle in the picture has everything exposed so that you can see it. But I made a cover to go over the HAZARDOUS VOLTAGE parts before I used it... I'm dumb, but not that dumb.

Here is a link to my fusion jig. I said that a bent soup can might work too as a jig, but I liked using my jig.

Here is a photo of a U-turn that I made with the paddle and jig. I also used a power miter saw to cut the angles.

I suspect that the socket fusion method is better, but I couldn't figure out a way to easily make a socket fusion tool that was teflon coated. It is possible to rent the equipment to do socket fusion.

BTW, if you're going to be fusing pipe, and believe me, you are going to be fusing pipe, be sure to pressure test before you bury it. Here's a link to how I did that.

Best regards,

-AC_Hacker

[Ko_deZ]

Allright guys. Having some issues with my camera, so no pictures of the HXs. I will provide contact details though:

www.hrale.com
zhuojq@hrale.com <-- Ask for Jason. Say Morgan referred you.

Good luck with your ordering!

Best regards
Morgan

[S-F]

Thought I'd toss this one in there.

I have met several geothermal folks out here over the while. The ones I have had the best rapport with have ALL told me they would lend me their socket fusion tools If I needed them. The folks who tried to push GSHP on me even though the ROI would be ∞ + didn't even think about such things.

The moral of the story is to get to know the HVAC guys who got into it back in the day because they were on the same train of thought we are on.

[AC_Hacker]

Originally Posted by S-F

...The ones I have had the best rapport with have ALL told me they would lend me their socket fusion tools If I needed them...

Being able to borrow fusion tools would be very useful.

On the other hand, for those who are not as lucky as you are, it is possible to bring your tubes inside where your heat pump is, and use metal manifolds, which can be purchased or made from copper parts. Soldering is ok for this because your pressure is low and your temperature excursions are not so bad.

Yeah, I feel pretty proud to have been able to make a fusion paddle out of thrift store parts, but making a fusion device that could do socket welding is beyond my skill set, I must admit. The issue was the teflon coating... you gotta be able to get the molten HDPE off of the heated surface without it sticking.

Howard, my machine processes guru did say that there is a shop here in town that can teflon coat things. If there's something like that here, it's available other places too.

I hadn't even thought about bringing the loop ends inside, before a few days ago.

I came across a training video the other day, it was a real goldmine of ideas. Will share soon.

-AC_Hacker

[Geo NR Gee]

Originally Posted by AC_Hacker

Yeah, I feel pretty proud to have been able to make a fusion paddle out of thrift store parts, but making a fusion device that could do socket welding is beyond my skill set, I must admit. The issue was the teflon coating... you gotta be able to get the molten HDPE off of the heated surface without it sticking.

Howard, my machine processes guru did say that there is a shop here in town that can teflon coat things. If there's something like that here, it's available other places too.

I hadn't even thought about bringing the loop ends inside, before a few days ago.

I came across a training video the other day, it was a real goldmine of ideas. Will share soon.

-AC_Hacker

So if you had access to a lathe, what would the dimensions be of the sockets? I thought about making my own and having them coated, but didn't know what the dimensions would be before the coating? Are most folks using 1" pipe down the boreholes?

Can't wait for the ideas on the training video?