The Homemade Heat Pump Manifesto

[Vlad]

AC_Hacker how did you grout your loops (it might be somewhere in your posts but I missed it somehow)? What did you use for grouting? This step was harder for me then drilling. I am still looking for solution how to pump grout 60 feet down through 1 1/2 hose. I know I can buy grout pump but for DIY they are too expensive.

[AC_Hacker]

Originally Posted by Vlad

AC_Hacker how did you grout your loops (it might be somewhere in your posts but I missed it somehow)? What did you use for grouting? This step was harder for me then drilling. I am still looking for solution how to pump grout 60 feet down through 1 1/2 hose. I know I can buy grout pump but for DIY they are too expensive.

Vlad,

Yeah, it's in there someplace.

Here's the story...

As far as I could determine, the purpose of the grout was two-fold:

1. To improve thermal transmission around the pipes.

2. To seal the bore-hole and prevent cross-aquifer contamination.

The method is to use a commercial grouting mix, or to make your own. The most often repeated was Mix-111

When I decided that I didn't want to punch through the hard-pan, I realized that I wasn't going to create the problem of cross-contamination, so that aspect of grouting didn't apply. Also while I was digging in August, the hottest and driest month, I noticed that I was digging through wet sand. I checked out the thermal transmissivity of wet sand and realized that it was as good or better than grout.

So, to answer your question, I didn't use grout, instead I put the sand & clay back in the hole (last out, first in) and flooded the hole with water as I did it to help the bore-hole settle as fast as possible. It's been about a year and there has been almost no visible settling of the boreholes. The trenches were a different matter.

I know that the 'best practice' industry procedure is to pump grout through a pipe starting at the bottom and working up to the top. I think that if you're going to grout, mixing your grout just a bit on the wet side and pouring it down from the top would get you there. You might get some voids, but I think they would be minor.

Regards,

-AC_Hacker

[Vlad]

AC_Hacker here is the link to one of Canadian refrigeration suppliers Refrigerative Supply
You can download their catalog. The catalog has a lot of information. We used it to design and build complete system from scratch starting from compressor and up. It has very nice tables for compressors coils heat exchangers etc.

[AC_Hacker]

Originally Posted by Vlad

The catalog has a lot of information. We used it to design and build complete system from scratch starting from compressor and up...

Vlad,

This is an excellent resource.

After I've looked it over more closely, I'm sure I'll have questions.

Thanks,

-AC_Hacker

[pachai]

AC,
You asked a question, I think I have the answer -
and I'll clarify where I stand/sit.

>>>Is there any way to have GFI for 240 volts?

On the Electric Vehicle Distribution List (EVDL),
someone pointed out that Home Desperate sells
a Hot Tub GFCI Circuit Breaker. I ordered it mail order,
have not even opened the box. Plan to put it
in my driveway for my electric car.
(It is sidelined by my addition, just like your heat pump
thanks to your remodel :-)

I'm reading your posts, on the edge of my seat.
I'm signing soon with a contractor to build an addition,
and I'm thinking the backhoe could do trenches
for me, and maybe even holes.

My thought is to dig the trenches, then drill...
so the trencher doesn't damage the pipes.

Has anyone tried pile-driving to make the holes?
If I follow your approach, it is only about 18' down....
(maybe you can't compact the dirt enough?)


Thanks
Seth

[pachai]

I had 2 ideas on blades for diggers - opposite
ends of the spectrum.

My neighbor has a heavy spade shovel.
It looks like it has a 1" Oak handle.
I was thinking it might be possible to
couple it to a 1.5" steel pipe.
Or maybe to couple 2 of them, back to back?
(it always depends on the soil, might not
work here in Northern NJ, with hard soil :-)
This would be a crude auger.

Other idea - I googled electric Auger.
The motor, etc are expensive, but the
blades are not terribly expensive
for a professionally engineered and
manufactured widget. 32" long.
And they have a 36" extension.
Maybe 2 extensions could be used,
with reinforcement?

Electric 12 Volt Earth Auger/Post Hole Digger


Seth

[AC_Hacker]

Originally Posted by pachai

I'm reading your posts, on the edge of my seat.
I'm signing soon with a contractor to build an addition,
and I'm thinking the backhoe could do trenches
for me, and maybe even holes.

My thought is to dig the trenches, then drill...
so the trencher doesn't damage the pipes.

Has anyone tried pile-driving to make the holes?
If I follow your approach, it is only about 18' down....
(maybe you can't compact the dirt enough?)


Thanks
Seth

pachai (AKA: Seth),

Welcome aboard!

Thanks for the 220V GFI find!.

I'm thinking the backhoe could do trenches
for me, and maybe even holes.

Currently, there are two popular ways to do the loop field;

• boreholes
• slinkies-in-trenches

There are advantages and disadvantages to each.

Boreholes require the greatest effort and/or expense, on the other hand, the average depth of pipe in a borehole installation is deeper, where the earth temp is more stable (greater efficiency).

Slinkies-in-trenches have a shallower average depth and the fluctuations in seasonal earth temperature is greater (less efficiency), on the other hand, they are considerably easier to put in.

Sizing and drilling your loop field is not a casual task, you need to devour all the information you can, before you begin.

Has anyone tried pile-driving to make the holes?

One of the most popular methods of borehole drilling is called percussion drilling AKA: cable drilling.

If I follow your approach, it is only about 18' down....
(maybe you can't compact the dirt enough?)

Please understand, my guess that 18 feet is sufficient is a guess, not yet proven, but an educated guess.

Here are the factors I took into consideration:

• Winters in Portland Oregon are fairly moderate, especially compared to Minnisota, or Finland, or upstate New York. Most temperatures during the winter reach the 40s during the day and fall back into the low to middle 30s at night.
• My house is small, about 700 square feet.
• My house is very well insulated. I have been packing thick slabs of styrofoam inside the exterior walls. It's expensive and very labor intensive, but it works.
• The loopfield in my yard is located in moist sand, which is a very good situation for extracting heat.

So please don't get the idea that 18 feet deep is some kind of magic number. I think it will work for me. It may or may not work for you. You need to do your homework.

Your 12 volt digger looks interesting. I should tell you that when the digger hits a rock, it can really throw you around, so having a scaffold to take the shocks rather than your body is a real plus.

You should check out some of the gasoline powered well drills, for some ideas.

The electric motor is a good idea if you are in an urban area because it is quiet and the power is easily available. But there is the real danger of shocks.

If you're having an addition put on your house, you might be best off to have them use a shovel attachment on a back-hoe and dig a trench about 80 feet long and 6 to 8 feet deep and put about 300 feet or so of slinky in it and bury it. This would get you about 12,000 BTU per hour*. So you'd need to know the typical heat loss of your house and divide that by 12,000 BTU to see how many trenches to put in. *By the way, that 12,000 BTU figure is what you could expect here in Portland. You need to ask around to find out what is the rule of thumb for the area in which you live.

So once again, welcome aboard. Don't forget to ask Vlad about your drilling questions, he's built a very serious and powerful unit. I hope he takes loads of photos to share with us all.

Good luck Seth!

Regards,

-AC_Hacker

[pachai]

>>>Thanks for the 220V GFI find!.

The exact info on the
"Inexpensive rainproof, GFCI, Disconnect"

Spa Disconnect GFCI Load Center, 240V - 30A to 60A

Sorry, sometimes "off the top of my head" is..... :-)

[pachai]

AC Hacker,
Thanks for the advice. I saw your original plan for 32 holes,
and that's what I would probably need.


I didn't mention, I won a lottery on EVDL for charity...
a motor...just the size to run a drill. It has been begging
for a project for a year or so. (It's a Jim Husted special :-)
I just need to find batteries, it takes about 48 volts DC

Did you metnion about how long it took you to do each hole?
(That might be the factor for me that would push
me to hire someone qualified with the right tools:-)

Seth
PS if you are looking for a DC motor up in the Pacific NW...
The EV community found Jim Husted and sort of claimed
his time, but I think his motors have lots of other uses...
Jimerico, Electric Motors, Controllers, Adapters, and more!

[AC_Hacker]

Originally Posted by pachai

Did you metnion about how long it took you to do each hole? (That might be the factor for me that would push
me to hire someone qualified with the right tools:-)

Seth,

(I know that the 'Manifesto' thread is long and winding... the information below is there to be found, in greater detail.)

If you attempt to do something like this, you will surely discover that not only is there a huge difference in different kinds of soil & rock formations, but there is a considerable learning curve involved...

The first hole I did was 14 feet deep and it was done with a manual post hole auger, with extensions. My son who is 32 did most of the work but I took turns too. It probably took 5 or 6 hours of serious work.

The next holes I did myself, as my son lost interest. The next holes were done with a combination of electric auger and hand digging and took maybe 6 to 12 hours each (sometimes more). The biggest problem was a surface clay layer that I hit on every hole at 2 thru 5 feet. I pretty much had to use a pointed iron bar, pounding relentlessly, to get through. then I used the hand auger head attached to the electric auger which had to be dumped every 10 inches or so. There was also the problem with stones that ranged in size between golf balls to hiking boot size that had to be dealt with. I made a grabber tool to pull them out. All very slow.

Then I discovered that I could use a very large shop vac, once I got down past the clay, which helped with sand removal and the end of the suction pipe was enough to get through the sand. Stone removal was still a problem. So the time was 6 to 8 hours (sometimes 12 hours or more) per hole. The biggest problem was getting through the clay... it was really tough.

Finally, toward the end, I discovered that if I used a water jet along with a specially made bit, I could get through the clay in about 4 to 6 minutes. Then I'd have to do a bit of work to get the mud out of the hole, then the shop vac for the sand, and still I had to deal with large stones. So at this stage, I'd say The holes were maybe 4 to 6 hours per hole.

Vlad has built a real monster of a rig, and he can grind through solid rock and anything else in his way. He says it doesn't take him very long for each hole, but I don't remember if he actually said how long he took.

Certain parts of the country had massive glaciers and rivers that accounted for the soil formations. It's that way where I live and I think it's the same for Vlad. Other parts of the country, like parts of the South East have maybe 60 to 80 feet of sandy loam, and tools like I made and used would have worked very well there. Tools like what Vlad made might be over-kill.

As I recall, you're somewhere in New Jersey, so my guess is that there was some glaciation several thousand years back... if there is sandy loam over the rocks, like to a depth of maybe 10 feet, trenches & slinky would seem like a good fit.

You should crack open the yellow pages and call up some well drillers. Call every one in the book. They're unappreciated and very knowledgeable about the very issue you are considering. They'll let you know what the soil conditions are likely to be, and what they would charge to do it for you.

Another thing you might try is to go and buy a hand powered post hole auger. They're about $45. Make sure you get one that uses 3/4" water pipe as a handle, that way it will be easy to add extensions. The 3/4 " extensions will maybe be $8 each. I found that 4 foot extensions worked out pretty well. But sometimes a 2 foot or 3 foot extension was pretty useful. Get at least two extensions, you can get more if you need more.

You'll gain tremendous insight by digging down 10 or 12 feet. You'll know for sure what you have in your yard. You'll definitely gain more than $60 worth of knowledge.

My contention all along is that it is possible for someone with gumption and time and limited tools to do their own loop field. I did it... but it was not a piece of cake.

The best price I got for a borehole was $7000 for 200 feet... grouted and all. That's serious money to me.

Now I now know that it's serious work drilling those holes too.

But it is possible.

Hope this helps.

Regards,

-AC_Hacker