Geothermal - Wells

Phew, the wells for the geothermal ground-loops are drilled, the ground-loops themselves are installed, pressure-tested, and grouted in place for eternity, and the pump (not heat-pump) is installed in our basement.

The drilling was done by Colorado Geothermal Drilling, and we are happy to recommend them.

The drilling equipment started showing up on Wednesday, and we dismantled the fence to our backyard.

The Drilling Rig was actually a custom job mounted on a skid-steer. Pretty much the only way we could have fit a drilling rig onto our property, as it turned out.

The plan was to drill down to 300 feet three times, with the wells spaced twenty feet apart. This gives us 900 linear feet of vertical well, which exceeds the 200 feet per ton of heat pump capacity (we are going to have a 4-ton heat pump) rule of thumb used in Colorado. It turns out they drilled the well closest to the house 300 feet deep, moved over 20 feet and drilled the next well 280 feet deep, moved over another 20 feet and drilled the last well 260 feet. It still adds up to 900 linear feet, but I would have preferred we got the full 300 feet on each well. 

The driller hit substantial ground water about 70 feet below ground. That's great in the long-term, as it means our ground loops should have really good thermal conductivity to the surrounding earth. In the short-term, though, the extra water that came up while drilling meant an extra $3,000 in water disposal fees. These two temporary tanks lived in our driveway this week, and vacuum trucks came and emptied them several times as the water kept coming up.

After drilling each well, they ran HDPE pipe down hole. It came in these big reels:

Once the wells were drilled and the vertical pipe installed, tested, and grouted in place, the drilling crew used an excavator to dig a four-foot-deep trench to connect the wells to the house.

Of course, unknown to anyone, two of our lawn sprinkler lines AND OUR INTERNET CABLE crossed where the trench would be dug.

Sigh. I was able to do a temporary repair of the internet line so Brianna and I could continue to work from home, and the kids could continue to watch Disney Plus, but I'm not really sure how much longer that cable will last.

And here's where the pipes enter the house, and what the ground-loop pump looks like inside the house:

Those lines on the floor will be connected to the heat pump when it's installed. The lines are filled with a water/methanol mix. We still haven't gotten word from the electric utility about when they can upgrade our electrical service, so we have had to push off the actual heat pump instalation until June (hopefully).

Our front and back yards are completely trashed - we have no grass left. We were warned, but I don't think we really quite understood. We also have this giant pile of sand that came up from drilling through sandstone:

And one of our sprinkler boxes got smashed and the valve solenoids broke off.

Still, we are very happy to be making progress on this project, and thrilled we were able to get on the driller's schedule this quickly.