Small and crude GSHP for a Michigan garage

[pick1e]

Originally Posted by Ron342

Great Work - But I think you will be limited in your depth if not by the rocks then by hitting water sand which will flow & sift out of your digger ears on the way up! That happened to me at ~ 22 ft Whats your water table at??

Thanks! That's a good point. I don't know exactly where our water table is but it shouldn't be very deep. I'm in the flats of Michigan that used to be lakebed. A friend told me his family had a 17ft water well on a farm half an hour from here.

If I ran into the flowing sand I wonder if I could throw some of the really sticky silty stuff I've dug up so far down the hole and mix it up in order to make it solid enough to bring up on the auger.

Whereabouts are you? Did you install a system or just experimenting? I'd love to know the details. Sounds like you went down pretty far but maybe for something else since you mention an air unit below?

Originally Posted by Ron342

You will also quickly find you need a 3 leg tripod with a pulley to pull out the digger as I did. Plan on having large hairy arms!

No doubt! I'm already thinking of a derrick apparatus at only 7 ft. My arms are puny so far.

Originally Posted by Ron342

I did find though that a 8-10 hp pump with 1 or 1 1/2 pipe ending with a nozzle at about 70 - 100 psi will jet down as far as 60-80 feet really quickly if you don't hit roots or rocks bigger that say 1 1/2 in.I hit marine clay there which ended it. Its a quick way to blow down some holes - dig a trench back from the hole to a pit for the return water to go and settle for the pump suction hose - fill it before you start and during as you'll loose some.

Can I borrow yours? Did it bring up the rocks or go around them? I'd like to try this but would hate to blow a couple hundred bucks if it didn't work. Did you use a pump made for a pressure washer or designed for a different purpose? How about the head?

Originally Posted by Ron342

I think copper is great if you have it around, 1" copper though will cost at least $25 per 10 ft - many times more that HDPE Copper is certainly easier to solder in a U joint and makes a nice straight drop - but I also think the critics are right that most soil has such low conduction that you will need more hole than you think - unless you can tap into a long strata of water with maybe some movement! I believe the conventional wisdom is 200 ft of hole per ton which I think is 12,000 btu

200ft per ton is what I hear with PE pipe. I'm shooting for half that with copper. I figure if soil is normally between 1 and 2 W/m-K and they are figuring 200ft with PE pipe which is about 0.5 W/m-K then at worst I should be able to double the heat extraction with copper instead of PE, thereby halving the required length to about 100ft per ton. We'll see though. I can always add more later.

Originally Posted by Ron342

I have wondered about running the cold refrigerant line of my outdoor heat pump (air) unit through a long trough in which the ground water is pumped to pick up ground heat (Just as a supplement) before it goes into the coil in my outside unit. This wouldnt require going into the refrigerant line - but haven't had the nerve to try it.

You mean basically running warm ground water over the evaporator? I think it would probably ice up like mine did pretty quickly. That wouldn't be much of a problem though if you made your own evaporator coil. As I recall the thermal conductivity of ice is actually higher than soil, just that if you ice up your current evaporator you eliminate the surface area of the fins.

Originally Posted by Ron342

Keep up the great work and posts - but damn its cold there.

Thanks! and yes.

[pick1e]

Originally Posted by RobertSmalls

This thread and ACHacker's have gotten me interested in boring. I've always assumed northeastern Buffalo has too shallow of soil for me to dig a borehole, but the USDA has done a soil survey on the area: Web Soil Survey

Thanks for the link I didn't even think to check there. *dopeslap*

Originally Posted by RobertSmalls

There's an underpass on an expressway about a mile from here that exposes bedrock (shale) at a depth of a few feet. There's no hope of boring through that, is there?

D'oh! I'm no expert but that doesn't sound very promising. Probably going to need professional drilling equipment for boreholes. You might look into a horizontal trench type loop instead for a DIY possibility.

Originally Posted by RobertSmalls

The floor of my basement is about four feet below ground level, so I'll assume bedrock (and the water table) is deeper than five or six feet, at least.

Again that doesn't sound too promising for boreholes There must be a reason why they don't go down any further. Basements around here are full depth, 7-8 feet.

Here's me:

99A—​Urban land-​Parkhill complex, 0 to 3 percent slopes
Map Unit Setting

* Elevation: 590 to 620 feet
* Mean annual precipitation: 32 to 32 inches
* Mean annual air temperature: 48 to 48 degrees F
* Frost-​free period: 137 to 189 days

Map Unit Composition

* Urban land: 58 percent
* Parkhill and similar soils: 35 percent
* Minor components: 7 percent

Description of Parkhill
Setting

* Landform: Till-​floored lake plains
* Landform position (two-​dimensional): Toeslope
* Landform position (three-​dimensional): Talf
* Down-​slope shape: Linear
* Across-​slope shape: Linear
* Parent material: Loamy till

Properties and qualities

* Slope: 0 to 2 percent
* Depth to restrictive feature: More than 80 inches
* Drainage class: Poorly drained
* Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.20 to 2.00 in/hr)
* Depth to water table: About 0 inches
* Frequency of flooding: None
* Frequency of ponding: Frequent
* Calcium carbonate, maximum content: 35 percent
* Available water capacity: High (about 10.5 inches)

Interpretive groups

* Land capability (nonirrigated): 2w

Typical profile

* 0 to 11 inches: Loam
* 11 to 20 inches: Clay loam
* 20 to 32 inches: Clay loam
* 32 to 80 inches: Clay loam

[RobertSmalls]

It is a full depth basement, for the 1920's. People were shorter back then, their expectations were lower, and digging and artificial lighting were both expensive. Hence, I have large basement windows, fully above ground.

If you can produce results from a 12' borehole, I might have to try it myself and see if I can bore an 8' hole here. I have modest heating and cooling needs, and a modest GSHP with a modest cold sink may be all I need.

Any thoughts on just using a ground source heat exchanger? If you could heat the garage to 45°F in the middle of winter, that would be a huge improvement with (hopefully) less electricity consumption.

[pick1e]

Originally Posted by RobertSmalls

It is a full depth basement, for the 1920's. People were shorter back then, their expectations were lower, and digging and artificial lighting were both expensive. Hence, I have large basement windows, fully above ground.

I didn't even think about you having an older house *dopeslap again* I suppose that's close to what we have around here in turn of the century farmhouses.

Originally Posted by RobertSmalls

Any thoughts on just using a ground source heat exchanger? If you could heat the garage to 45°F in the middle of winter, that would be a huge improvement with (hopefully) less electricity consumption.

Yea I thought about it briefly but then concentrated on the heat pump in order to be able to heat it up to working temperature when I wanted, especially for things like gluing or finishing where it should be above 60.

But definitely for baseline heat I will certainly try it. My plan is to build things so as not to pigeonhole myself into any particular system. I want to get a ground loop in and play with it in different configurations. For example supplementing with solar collectors for heat in the winter and heat storage in the summer.

[pick1e]

Iraq may not have had any weapons of mass destruction, but I do:



Larry made this for me today. Hatchet head welded to a 12ft pipe. Worked like a charm. Here's what was in my way:



It's not a boulder but enough to stop my manual auger. After that came up I easily continued past 8 ft.

[North_Pole_Guy]

[QUOTE=pick1e;10286]

He mentions some auto-convection heat pipes, which is cool. I wondered about that. I wonder if I could bury some before pouring a driveway to passively collect heat in the summer and melt the snow in the winter


On the Trans-Alaska Pipeline something similar is used only backwards to re-freeze the ground hard during the winter.
There is pipes at each pipe support that go down into the ground that have ammonia in them that boils off and gives the heat up on the fins mounted on the top. As the liquid re condenses and turns back to liquid it runs back down to the bottom of the device where the process starts all over again. Right now the ammonia is being slowly replaced with C02. The key is that it does not work until its really cold outside.

I have often thought about building a few scale ones that you could run through an exterior wall and into the back of your freezer to help reduce your freezer run time when it is cold outside. The cheaper fix that I go with is to just set the freezer outside, it does not run all winter..

http://faculty.virginia.edu/ribando/.../pipeline1.gif

http://faculty.virginia.edu/ribando/.../pipeline4.gif

[pick1e]

Originally Posted by North_Pole_Guy

On the Trans-Alaska Pipeline something similar is used only backwards to re-freeze the ground hard during the winter.

That's awesome! I had no idea. Thanks for posting that.

Now that I think about it for the driveway though, you could probably get away with a passive ground loop... just turn it on for a day to melt the snow. You could run it in the summer too to store heat for the winter.

[pick1e]

Before I left town for a week I received a gift from Larry:



He brought over a nice piece of 22ft x 2in pipe sharpened at one end and a nice big ram. This was great for pounding through the rocks that were giving the auger a hard time. We could pound it in maybe 4 to 6 inches at a time but it was pretty difficult to work it back out of the ground, especially with one person. 18" pipe wrench necessary.

At around 14ft we left the glacial till and went into the hard gray clay that was really tough. Ancient lake bed I guess. Oddly enough though it seemed less labor intensive to use the auger since there were very few stones. Even though it was very dense the auger seemed to cut through it nicely, I think because the particles are so fine and very few stones. Almost 2ft per hour unless I had to switch back to the ram. Maybe faster if I had a derrick built. Lots of good upper body workout just lifting the pipe out of the hole.

Here's that nice, tough, sticky clay:



So a few hours this weekend got me down past 18ft. At that point it was dusk and I seemed to be hitting rock again. I will try to hit it with the ram (a couple inches left before bottoming out) but it could very well be limestone. Either way I'd be happy with that depth. 25ft is my limit anyway since I don't intend to get well permits.




I'm happy to have been able to get this deep with only peanut-butter-and-jelly power, no help from fossil fuel or the grid... aside from the manufacturing of the pipes, hand tools, and a few minutes of welding... but who's counting?

[North_Pole_Guy]

Pick1e,
Have you ever given thought about just driving a 2" sand point with a jackhammer? That is what I drove my water well with a few years back. 40' deep in only a few hours with a borrowed 90 lb jack hammer. I would think that you might be able to run a loop Down and back up then grout it in inside a two inch case.

[pick1e]

Originally Posted by North_Pole_Guy

Have you ever given thought about just driving a 2" sand point with a jackhammer?

I know of the method but hadn't really looked into it much because I don't know anybody who has the equipment to borrow.

My guess is that it doesn't work very well in this area due to the highly compacted clay- the displaced soil wouldn't have anywhere to go. But that's just a guess. The end of that 2" pipe I used to get past stones was open (no point, just a sharpened tube, so less material to displace than with a point) and it had to be brought up to be cleaned out at least every 6in. Otherwise it would get increasingly hard to drive even with that huge driver.

Also it was interesting to dig down and bring up the soil to see what I was up against. Because of the history of glaciers here, what you find under the surface on your property can be totally different from what's under your neighbor's property.

You might have more sandy soil where you live? If I knew anyone with a jack hammer I'd give it a shot for my next hole. Coming to Michigan any time soon? :P