Geothermal - Part 1

If you have ever thought of installing a geothermal (ground source) heat pump, this is the year to do it.  The federal goverment is giving you a 30% tax credit.  There is no limit on the geothermal tax credit like there is with installing energy efficient windows and doors where the maximum you can claim is $1500.  Also, if you are a rural electric coop member with Central Rural Electric Coop, then you can get $750/ton back provided you have the required amount of insulation in your attic and walls. 

The whole idea of a geothermal system is to use the constant temperature of the earth to heat and cool your home.  A good site for understanding this concept is this:  http://www.igshpa.okstate.edu/geothermal/geothermal.htm

In order for this to work, they either drill wells or dig trenches in the ground in which they insert tubing that is filled with water.  The water circulates and picks heat from your home and disperses it into the ground.  The opposite happens in the winter time.  (Honestly, I don't understand the "heating the house in the wintertime" part, but I've been assured that it works.)

Apparently, drilling is more expensive than trenching.  Fortunately, we have a large enough area out in front of the house that we were able to go the trenching route.  Air-O is the contractor we selected for our geothermal system.  They have a big, honking Ditch Witch trencher they brought out to do the trenching.  Here is a picture of it in action. 

Once the trenches were dug, tubing was laid in them.  Notice below there are 2 in each trench, one going in and one coming out.  They form a closed loop that is filled with a mixture of water and anti-freeze.  One tube brings the water mixture  from the house out to the ground where the heat exchange takes place and the other returns the water to the units inside the house.  Also, notice the water in the bottom of the hole.  It has been a very wet year!

Some of the trenching had to be done by hand.  We have buried electric, cable and telephone lines that were marked in advance by "Okie".  Then these 2 guys had to dig the trenches that were going to be in the vicinity of those lines.  I baked them some cookies because they worked so hard!  Way to go guys!!

That's about all I have time for tonight.  I'll finish up with pictures of the finished excavation and of the inside units later this week.  Stay tuned!