Category Archives: Geoexchange

Geothermal, Part 3: Finally!

The last phase of the geothermal installation is finally complete, starting last Sunday to the finishing touches on Friday.

The first part was done by me on Sunday afternoon, starting with a pristine hall closet door.

Which was ripped from the wall, along with the door frame and wall board.

Monday morning the crew started dismantling the old furnace.

Out with the old, shelf and all!

The first piece to be installed was the circulating pump (on the left hand side of the wall) which attaches to the ground loops. They also insulated below the old shelf, which apparently was essentially open to attic air. Now the closet is well sealed and will draw air from the house instead of the attic.

In with the new, all 350lbs of it! Then came the finicky parts. They’ve already installed the auxiliary heat coils above the blower, and now they’re installing all the pipe connections to the pump. As you can see the new one is quite a bit larger, so they didn’t have a lot of room to work.

Meanwhile outside, the pipes are connected to the pipe purger. Ten gallons of antifreeze is added to the big blue tank and enough water to top it off. Then the pump is started to circulate the fluid through the well, purge the air and top off the pipes.

The well loops are done separately from the furnace first. Then once he’s assured the pipes are purged, he added the furnace pipes into the loop and purged them as well.

Something’s missing here…Woo hoo, no air conditioner! It won’t stay that clean though.

The next day, they insulated the pipes and encapsulated the pipes and purge valves with this insulated chimney. It’s a bit of an eyesore, but it’s on the side of the house that is not often seen. Eventually I’ll be building a trellis to shade that side of the house and grow kiwi vines, and we can paint the top to blend it in better.

Most the day Tuesday was spent adding a sub-panel in the closet, wiring the furnace, building the conduit from the furnace to the original outflow pipe, installing the drain, installing the thermostat, and setting all the dip switches. Friday was just a touch up day, insulating the attic pipes and resecuring the pump to the wall, and that’s it! Simple as that! Seven full days over three weeks. The front lawn is still a mess but the water hasn’t receded yet to do the final landscaping. The closet door is on order and should arrive in a couple of weeks.

Now that it’s installed, we haven’t had to use it. The weather has been perfect, and we haven’t needed heating or cooling. We did test it of course and it was incredibly quiet. It’ll be even more quiet when we install the new door.

Geothermal, Part 2: The Red Rock

The work on the second phase of installation started in the attic on Tuesday morning, getting the pipes installed in the furnace closet.

That done, they drilled the holes to the exterior. Amazingly they were not bothered by the wasps that infest that wall. Of course I did spray the gap between the stone and wood facing the night before, hoping to reduce the population to a manageable level. Apparently it worked.

The pipes were pulled through the wall, cut to length, jointed with elbows so the pipe would lay flush against the wall, then capped.

Then the digging began, and to my surprise they found the house was sitting directly on some very hard sandstone. It turns out the red rock was a foot below the surface just about everywhere they had to dig and was at least 4 feet deep (the trenches needed to be 4 feet deep).

Needless to say, that slowed down the digging process considerably and they didn’t start attaching the well pipes until late afternoon.

The pipes were all connected using a combination of heat welding when the were attaching fittings…

…and heat splicing, when connecting the same sized pipes.

By midday on Wednesday, the pipes were all connected in one continuous loop. A good thing they finished when they did since the trench was slowly filling with water.

Once all the pipes were connected they did a pressure test for about 3 hours at 90-100 psi. During that time, they attempted repairs on the drill rig, that had suffered so much abuse when it was stuck in the mud.

No leaks were found, and the trenches were backfilled. Part 2 is complete.

Geothermal, still part 1 (sigh!)

The drilling crew arrived around noon on Monday to extricate the rig, which was not as easy as they’d hoped. It took roughly an hour of moving the truck in one direction or the other with the aid of the backhoe, then backfilling the trenches and tamping down a “roadbed”, then hand digging all the mud out from behind the fuel tanks before they were finally able to back the rig all the way up the hillside.

Leaving our front yard looking like this!

They were able to fit the rig between the Bradford pear and the hillside, to avoid getting stuck again when they inevitably hit water on the third well.

As they prepared to drill the third well, I tried to snap a shot of the drill head (to the left of Chris’ head), which is not very big. I haven’t quite figured out how all the drilled out material gets to the surface but obviously it does.

The pipe is ready to go. The pipe is precharged with water, which adds to its weight when it’s sent down the well.

The end of the pipe (or rather the bottom). This is the attachment that makes to loop in the pipe, and holds the weighted rod that pushes the pipe to the bottom of the well.

As I said, they’d inevitably hit water, and just past eighty feet, they did so. The water, of course, filled in the trenches the truck had left in the lawn, preventing them from being backfilled.

The drilling is done and only one casualty: a branch from the pear tree being dragged away.

Geothermal, Part 1: The RED MUD

After many months of dealing with contract proposals, we finally hired someone to install our new geothermal heat pump system. The first phase is the drilling of three wells and installing the vertical pipe loops.

The drill team arrived on Tuesday afternoon to set up the drill rig, an impressive sight at dawn the next morning. Wednesday started rainy , but cleared by the time the drill team showed up to start work.

The other piece of equipment left on our lawn is the pump for the bentonite clay used to seal the wells.

The drilling started around 9AM. The soil had enough moisture to keep down the dust, and it was fascinating to watch the different colors of the soil layers. The wells are 200 feet deep, using extension segments of 20 feet on the main drill driver. About 50 feet down the drill hit sandstone, but didn’t hesitate long before reaching the next layer.

…and then they hit the aquifer. The water must have been under a bit of pressure because it came gushing up…and headed towards the house. We had to scramble to make sure the house didn’t flood with that incredibly red water, and the only place for the water to go was out into the front yard.

truck in mud

When it came time to move the truck to the second drill site the soil was quite saturated.
This was the first set of ruts in the front yard which they’ll fix after the next phase of installation.

The second drilling went well, but of course they hit water again and even more of the front lawn was saturated. I should mention that our soil out front is mostly sand (75%) and clay (25%).

At this point in the operation, the crew is lifting all the extension segments out of the hole (photo left) which they’ve already sealed most of the way with bentonite.

There’s the hole! About eight inches wide and 200 feet deep.

Once the extension pieces are removed the piping is inserted. The pipe is prelooped and fitted with an attachment to hold a weighted bar (straight metal bar pictured left). The pipe is set on a reel and once the bar is released it, quite rapidly, pushes the pipe down to the bottom of the well.

Finally the wells are capped with more bentonite clay.

Then they tried to move the truck to the third drilling site.

You can see that didn’t go so well. The theory of rocking the truck back and forth is sound, unfortunately, as I said, our soil is mostly sand, 50 feet deep until you reach the sandstone. There is no bottom. The truck continued the dig deeper and deeper, until the mud started pulling pieces off the truck. One of the metal steps broke off and jammed into the mud, then broke the front tire hub cap. At that point they gave up.

And there is sits until Monday, when they can bring in their backhoe and extricate it from the mud and finish phase 1 (there’s still another well to dig) and phase 2 of the project.

While the man in the mud slowly dries.