Geothermal heat pump install with crawlspace encapsulation

kenmac · Oct 1, 2014

Country Geek said:
1. Cave-ins: the trenches have been caving in. This is mainly because of the wet weather combined with my soil composition. Understandably, a man doesn't want to get down into a six foot trench to put in piping if it might cave in. .

If they are working in a trench that deep (I believe a 5' deep or deeper trench requires a trench box) without a trench box (a device used to keep a trench caving in and killing someone) And OSHA comes out or, someone is killed. That contractor is in trouble. When I have to dig that deep for plumbing. I have to rent a trench box

Country Geek · Oct 1, 2014

kenmac said:
If they are working in a trench that deep (I believe a 5' deep or deeper trench requires a trench box) without a trench box (a device used to keep a trench caving in and killing someone) And OSHA comes out or, someone is killed. That contractor is in trouble. When I have to dig that deep for plumbing. I have to rent a trench box

I thought about that, but I wondered how a trench box would work in a trench where you are attaching hoses to the sides?

kenmac · Oct 1, 2014

Country Geek said:
I thought about that, but I wondered how a trench box would work in a trench where you are attaching hoses to the sides?

I have no idea. There are several type trench boxes, but OSHA isn't concerned with that as much as they are with safety. I have some plumber friends that have paid hefty fines for not using trench boxes. It wouldn't be your problem. Compliance is the responsible of the contractor. Last month about 40 miles from me, a plumber's helper was killed when the trench /hole he was working in collapsed. They were working on the weekend trying to avoid permits / and safety regulations/requirements. I would make sure he (the contractor) has plenty liability insurance, incase something happens to 1 of his employees on your property

farmer2009 · Oct 2, 2014

kenmac said:
I have no idea. There are several type trench boxes, but OSHA isn't concerned with that as much as they are with safety. I have some plumber friends that have paid hefty fines for not using trench boxes. It wouldn't be your problem. Compliance is the responsible of the contractor. Last month about 40 miles from me, a plumber's helper was killed when the trench /hole he was working in collapsed. They were working on the weekend trying to avoid permits / and safety regulations/requirements. I would make sure he (the contractor) has plenty liability insurance, incase something happens to 1 of his employees on your property

I was thinking the same thing. Especially the insurance part. Seems like I have seen boxes with just legs for the bottom 2 feet or so.

cre10 · Oct 2, 2014

So is he charging you more for boring since they couldn't dig trenches and since there was debris in the loop field excavation area? Are they grouting?

What brand of heat pump?

cre10 · Oct 12, 2014

Any updates or are they still trying to dig?

Country Geek · Oct 16, 2014

Sorry I haven't been keeping up with the updates. I had some business travel and there have been some delays in the project.

They are still doing the boring. They started the boring and got two lines done when the boring machine had a hydraulic cylinder break. It took a few days to order a new one and get it installed. Then we had torrential rain for a few days and it was too wet to work. They just re-started the boring work today.

To answer the other question, they are not charging me more for the boring because it was their decision to switch to that. I realize that also might have something to do with why it's going kinda slow.

Re: grout they are not grouting because the boreholes are "self-grouting." The borehole isn't much larger than the line being pulled through and they are using high pressure water as part of the boring process so it muds up and settles around the line. I think that's right. It was explained to me a week or so ago and that's my memory of it.

I have some pictures that I will try to get up in a day or so.

dodge man · Oct 17, 2014

I had geo thermal installed last week. I'll share a little bit about my system. Its a 4 ton unit with the backup heat being electric. We had propane heat before and I wanted to do away with it altogether. We also have a wood fireplace for emergency heat during a power loss. I would also be worried about hooking up a generator since it seems like it has some sensitive electronics.

They did directional boring for the piping. There is a company that does nothing but geothermal and they came in and did it in a day. The even directional bored the piping into the middle of my basement where the furnace is installed. It took them about 3 days to install the furnace, hook up the duct work to the old ducts and install a hot water storage tank and a new electric water heater. Its my understanding that the water storage tank will preheat the water depending on if you geothermal is running or not.

Rough numbers, $20,000 total for the installation and equipment cost. We will get about $5500 back on tax rebates etc. A conventional LP and AC unit could have been installed for about $5000 to $7500 depending on the quality of the unit. We pay about 8 cents a KW hour for the geo while the normal rate is about 12 cents.

Rough numbers for energy usage, our house is 1900 sq ft with a full basement. Climate, we are about even north and south with Peoria Illinois. House has new windows and probably average insulation. $990 a year for heat, hot water, AC. The number that blows me away is the total AC cost for a year is less than $100. Other people told me this also, the AC part of the geo is almost, but not quite free. Roughly a third of the yearly bills is for making hot water. They are estimating the return on investment compared to a convential LP furnace and AC unit to be 3 years.

All and all I'm pretty happy with the unit. It hasn't been very cold here yet so the unit hasn't run much for heat and I ran the cold side of it one day just to see how it works and it seems good.

Country Geek · Oct 25, 2014

Finally have some down time with the computer to put up some pictures. As I said earlier, the ground loop contractor started with a plan to dig 7 trenches but abandoned that after the first trench because of cave-ins and running into junk that my clearing contractor buried 16 years ago so they switched to boring. They are boring 12 runs 150 feet long and 10 feet deep. It has been frustratingly slow work, they are getting about 1 to 1.5 bores done a day. This is mainly because of frequent equipment breakdowns and the distance from my place to parts stores or service that they can use. However in the end I think this will be better because it's must less ground disturbance, and the lines will be deeper (the original trench plan was 6 feet deep with lines at 6 feet and 4 feet.

I found out the plan had changed when the boring machine showed up at my place.

They dug two trenches, 3 feet deep, 150 apart, parallel to each other and the bore from one to the other.

Here is the boring machine in position to dig:

The borer, from the front:

This "aerial" shot (from the roof of my barn) shows the whole operation. The piles of dirt at the far end of the pasture are the far trench that they are boring toward, from the trench at near end. The dirt area to the left is the one trench they completed before switching to boring.

During the boring, one man operates the machine and another guides it using some pretty sophisticated electronics. The tip of the drill contains a precise transponder (they told me the transponder is costs $3K!) and his assistant uses this detector to keep track of where the bit is (laterally and depth) and give directions to the driller to keep it straight.

Once the drill pokes out of the far trench, they attach the geo line to it using "chinese fingers" and then pull it back through.

Here's a picture of the header trench with several of the lines completed. They aren't worried about the water, in fact wet soil conducts heat better than dry, apparently. My land does not perk, and this water is from rain over a week ago. They will pump it out when it's time to assemble the manifold.

That brings us to present day. 8 of 12 bore lines have been completed. Looks like at least another week of fieldwork to go.

Country Geek · Oct 31, 2014

They bored to the house today and got the supply and return lines into the crawlspace. There is still some fieldwork to do, need to finish testing the installed lines and then button the pasture back up. I talked to the field work contractor, he said my job was interesting because it turns out I have a layer of solid bedrock about 10 feet down. That holds water, which is why my trenches were so prone to cave-ins. But the good news is that the perpetually damp soil will conduct heat much better than dry soil would.

Ironically the propane tanker came today and made a delivery while they were working on the line to the house. Even more ironically, the gas was the cheapest price it's been in about 5 years... $1.91/gallon. Long term I know geo is still the way to go but interesting that gas is getting cheaper now. Well for now at least, I doubt that will last.