Geothermal Heat Systems

google is your friend.

It's a modified heat pump system, very simple, google a heat pump. The modification is that instead of having (or in addition to having) an outside cooling fan, it uses the ground as a cooler in the summer and a heater in the winter. The ground temp is very constant once you go down a few feet below frostline.

I have also been looking into these. I have been talking to a contractor that installs Water Furnace brand units. I have been told to expect the ground coil to last 100 years but the heat pump is only expected to last 10 to 15 years. He did tell me that his company removed an older Water Furnace (10 years old) and replaced it with a new one at the request of the customer. They took the old unit and installed it in the home of one of his employees and is still using it. The unit has about 16 years on it now and is still going. I was told the unit was replaced because of improvements in efficiency.

Put a Water Furnace unit in a house we built. 3500 sq ft, 3 zones on a single unit closed loop system. It was a 2 stage unit w/ a scroll compressor that reversed for the 2nd stage. Horrible design, compressor self destructed just past the warranty. Had bought a 10 year warranty but my dealer didn't send the money to water furnace so they wouldn't fix the unit. (On their way out of business) Replaced it with an American Standard unit, The coil was radial like Christmas tinsel instead of like a car radiator. It was more efficent than the geothermal unit.

Great advise thanks. I already have a forced air furnace does the system utilize an "A" coil in the furnace plenum just like my normal a/c unit? Where did you purchase your parts from for the install. I have not found a heating contractor that will allow me to do that in my area.

I used standard "climate master" unit. I had difficulty to find an AC guy to do the modification. Most of them don't know very much and are very afraid to modify anything. They only plug leaks and change parts until the system works... I was not impressed by their trade.

I found an inexperienced young AC contractor whom was only responsible to avoid freon leaks. I told him what to do, he did it properly, the system works well.

This system looks fairly straight forward to install and set up. I contacted my local "climate master" distributor and he will sell directly to me because our system falls under comercial use do to its size. I still will have to find a way to size my system properly. I would agree about the part slinging there are very few industries that actual understand things well enough to economicaly troubleshoot them.

The big expense is in the ground coupling. I am just finishing a commercial project here in Vegas that is approximately 350 tons. We have 200, 400ft deep thermal wells, each with 1-1/2 inch PE tubing for the ground couple. Each of the wells are injected with a special, thermally conductive grout to enhance the heat transfer. The wells are all manifolded together in a reverse return system to assure equal flow to all the wells. We are using Climate Master Heat Pumps and air to air heat recovery for ventilation. The building is going to end up with a LEED Gold level rating. Even though this system was more expensive then a conventional HVAC system, payback has been calculated at just over seven years. We are also in the process of installing 2 million dollars of PV's on the roof to make this one of the most energy efficient buildings in Nevada.

I have learned from the geothermal forum at greenbuildingtalk that it is important to have at least a couple bids to choose from. Also, I've also read literature stating the average life span is estimated to be 50 years, give or take depending on the system. Every manufacturer has a different warranty, so when you get estimates, make sure to find out detailed warranty info.

References from previous jobs are also very important. It easy to call oneself an expert but it is more difficult to prove it with installations that operated properly for many years. Without references, you are taking a risk. This should translate into a lower price.

The plastic pipes might last 50 years but we don't know because we don't have 50 years of history to look at.

The heat pump and components will not last much more than 20 years if that much. Anyway, you will then take advantage of the new higher performances available but you will have to pay for the new equipment.

When looking at these systems, one should look at a payback of 5 to 10 years. Anything more is too expensive for the increase in complexity.

Unfortunately, with the increase in energy cost that we are seeing it should be easier to hit five years of payback in the coming years.