The GeoExchange

10 Months After Installing Our GeoExchange System

2008-10-29T09:13:00.000-07:00

It’s been a while since a post. Over the summer we were very impressed with the air conditioning provided by our GeoExchange system. In used very little electricity (much, much less than previous years with a traditional AC unit) and was able to dehumidify the air very, very quickly. Now that it’s cold we’re using the heat again. Once we have a complete year of bills we’ll post the numbers for the past two or three years to show the difference.

The yard has returned to normal and you can’t tell that two 300 foot wells were dug and geothermal ground loop was run across our yard. The photo below shows our yard before and after. So once the system is installed, everything is back to normal pretty quickly.

Yard Before Installation (Winter)

Yard Immediately After Installation

Yard Now (Later Fall)

First Day with AC

2008-06-07T10:40:00.001-07:00

We finally had a good reason to turn the air conditioning on today since the temperatures shoot up to 98 degrees. I was very impressed with how well the system cooled the house. We went from 80% humidity down to 50% in about three hours and the house if a very comfortable 78 degrees (where we set the thermostat). The system has been running but not continually. So we’re very pleased with how the house feels but will wait to see the electricity bill. My sense is that it won’t be too bad, probably less than the electricity used to heat with the geoexchange system.

In other news we added some images of the geoexchange system in our basement to www.thegeoexchange.org.

All Done! Geoexchange is up and running.

2008-04-27T16:37:00.000-07:00

Actually it was done in the cold of late January. The entire process with lots of photos can now be seen at www.thegeoexchange.org. So far we’re very happy with the system – it’s comfortable and efficient. We’ll be putting our electricity and gas bills online soon to provide an estimate of how much we are saving.

Note, the actual geothermal heat pump is not shown in this picture. It is now in the empty space in the picture and looks like a normal furnace.

Drilling Begins January 14, 2008

2008-01-05T08:50:00.000-08:00

After a lengthy wait for a drilling permit, we’re good to go. The drilling is scheduled to take place January 14th and 15th, 2008. During this time three wells will be drilled and tubing will be run down each hole and then into the house. It should take about two days to complete.

Once the drilling is complete then the hardware will be installed and tested. Hopefully after that we won’t have to think about it for another 25 years or so.

Picture, video, and descriptions will follow once things get started January 14th.

Contract Signed!

2007-10-13T08:42:00.000-07:00

We've signed the contract and our equipment has been ordered. The contractor will receive the equipment in three weeks and we should be set up by mid-November.

Financing : Energy Efficient Home Improvement Loans & Second Mortgages

2007-08-10T10:22:00.000-07:00

Today I was doing research on the types of loans available. There’s some information about something called an Energy Efficient Mortgage (for new homes) and an Energy Efficient Home Improvement Loan for existing homes.

I called my mortgage company but they didn’t know anything about it (they’ll get back to me). As I understand it, the whole idea is that you save the amount (or more) on your heating and cooling bills and use this money to pay off the loan.

Next I called the state of Maryland Energy Administration. They didn’t have much information and suggested I call back in a week when someone who might have some information will return from information.

One possibility would be to get a second mortgage to pay for the system. They advantage with doing this is that the interest on the loan is tax deductible. At the same time I get the feeling there may be some fees and a higher interest rate that may make it unattractive.

In addition to my mortgage company I spoke to another company. They said everything looked good in terms of my credit, home value, … but since the subprime mess they had suspended second mortgages for a while.

So the research continues.

A Rough Measure of Ground Temperature

2007-08-09T12:15:00.000-07:00

The idea came to me that I could get a very crude measure the temperature of the water coming out my sink as another measure of ground temperature. This water had been sitting in the pipes overnight and would be the temperature of its surroundings. I took the lowest temperature as water came out of the tap and found this to be 20.4C or 68.7F at 7:00 AM in the morning. This is impressive since the temperature the past few days has been close to or over 100F.

I’m not sure how deep the pipes are in the ground or how long the water needs to be in the pipes to match the ground temperature. However, the 68.7F is an interesting number.

Where are we?

2007-08-06T17:05:00.000-07:00

The summer is drawing to a close and school will start soon. I’ll be headed back August 20th and the first day of classes will be August 27th. That’s when things get busy with all the teaching, grading, setting up labs, etc. Before then I’d like to make a decision on the geothermal/geoexhange system.

The problem, of course, is money. Both bids came in higher than expected by about $4,000. So I’m hoping at least one of the contractors is willing to negotiate with us. This may include working out a time that is easier for them in terms of scheduling, being able to show them that we have the money, or being willing to serve as a reference (if they do a good job). I suppose I could wait until there are more tax incentives but at the same time that has its own inherent risks (my furnace dies, demand for geothermal systems go up as a result of this blog, …).

It’s all a bit frustrating but I suppose that’s one reason geothermal systems aren’t that common right now.

What to call it? Geoexchange or Geothermal?

2007-08-05T11:44:00.000-07:00

Often the two names are used synonymously, but for the ground loop heat pump, geoexchange seems more appropriate to me. While the heat (thermal energy) is coming from the ground (geological), geothermal has the connotation of tapping into volcanic like activity. The term geoexchange implies that you are exchanging the heat or cool in your house with the ground. It’s kinda difficult to cool your house with an active volcano. Despite what I think, both terms are used interchangeably. The most common being geothermal heat pump system. However, when I think of geothermal I think of the photo above, not something that would go in my front yard.

Photo by my Mom (no really, she took this picture in 2005)

Geoexhange Video

2007-08-03T05:05:00.000-07:00

Here's a nice video of how a geoexchange system works from the Geothermal Heat Pump Consortium. It explains several ways the loops can be installed in the ground.

Vertical Wells – How Many and How Deep?

2007-08-02T14:18:00.000-07:00

Contractor #1 would dig a very deep (about 400 feet) single well. Contractor #2 would dig three wells (about 175 feet). I'm more comfortable with the three wells since in my mind there is solid rock way down there (can you tell I don't each Earth Science?). You get a drilling estimate (usually from a different company but managed by your contractor) but if they hit something unexpected it can cost more.

Since they're drilling I'm expecting it to mess the yard up pretty bad but not as bad as with a horizontal loop system where they really dig the yard up.

Where will the geoexchange loops go?

2007-07-27T12:58:00.000-07:00

Our house was built in the 1950's so the yard has several large trees that we aren't willing to have removed. So we'll have to go with a vertical loop, which requires a drilling rig. If you have a large area you don’t mind having trenched you can have the loop buried below the frost line (about 4 feet or so). This is called a horizontal loop. Since we don’t have such a space we’ll dig straight down. Vertical wells supposedly cost more but can be put in almost any location without removing any trees.

The other cool thing is that once everything is in place nothing will be visible except where the loop tubing goes in the house. So there won't be anything above ground in the yard, not even an A/C unit. This is nice because or backyard is very small and it would be nice to see the A/C unit gone.

Bids $$$

2007-07-26T16:38:00.000-07:00

We found two contractors from a link Sheila found on the GeoExchange Consortium’s website. It has a search feature by state and listed two contractors in our area.

Contractor #1
We talked on the phone and they sent us a form to complete with all kinds of information about my house (square feet space, current AC and furnace systems, ...). They then gave us a bid via email.

They came in about 23K for everything including the hot water. For the drilling the price can go up if they encounter problems (rock, UFOs, underground civilizations, …).

Contractor # 2
My experience with the second contractor got my enthusiasm back. The guy came out and we looked at the house and talked about geoexchange for about a half hour. Later their bid came in somewhat higher than the first contractor (about 25K for everything). So that makes things more complicated.

How it Works According to Wayne

2007-07-07T12:05:00.001-07:00

About four feet down (below the frostline) the ground stays at a fairly constant temperature year-round. For our location, a suburb of Washington, DC, it's about 55 degrees Fahrenheit. Geoexchange systems run a long, long, tube filled with water, and maybe some antifreeze underground. A pump moves the water through the loop as it passes through your house.

In the summer the loop enters the house and the 55-degree water absorbs the heat. The water, now warmer, goes outside back into the ground and cools back to 55 degrees. So your house is cooler and the ground is warmer. You just moved the heat somewhere else.

In the winter it’s a bit more complicated. The 55-degree water comes into the house through the loop. But most people would rather not live in a 55-degree home. So they have a machine, called a heat pump, which squeezes the heat out of the water in the loop. The water is then colder as it leaves and heads back into the ground and the house is now warmer. The water warms back up to 55 degrees underground and is eventually cycled back into the house.

Fans circulate the cold or hot air through the existing ducts, just like a regular cooling/heating system. Once it’s installed it all works without you having to think about it anymore.

A journey ...

2007-07-03T17:36:00.000-07:00

Several months ago Sheila and I started looking at replacing our heating and air conditioning system with geoexchange. I'm a high school science teacher and I instantly became intrigued with technology. To my mind it is a elegant solution to the problem of heating and cooling a home.

The web has lots of information about geoexchange but not much for the little guy trying to get it for his three bedroom home. So that's what this blog is about, Sheila and I finding our way as we research and endeavor to get a geoexchange system installed in our home.