Geothermal heat pump

[sunny h]

I'd like to know what sort of water heater those of you with geo systems are using with your desuperheaters and buffer tanks? I know a heater is needed to bring the water up the last bit, and for shoulder times of year when the system is not running a lot.

[gator37]

I believe the correct term from ARI is "Closed Loop Ground Coupled Heat Pump" (CLGCHP) unless they have changed it.

Originally (1991 or so) there was a problem with the correct configeration of desuperheaters in the hot water heater storage tank. You may want to check some of the manufacturers such as Climate Master and see what they provide or recommend.

[Angelb]

What's a Thermal Well Cookie?

Thermal well is use to control water cooling and heating system

[gregs1]

Hello,

I've been reading through the thread and cant imagine dealing with the wells and the iron or other things that could foul up a system.
I'm in a story and 1/2 cape here in PA with a 4 season oil set up with water baseboards. I originally started looking for a Central A\C system because the summers here can be down right soggy with humidity. What I found was for about 35% more money I could get a direct exchange geothermal system to do both heat and AC over the cost of a central AC system.
This system doesn't use wells or water/antifreeze loops. I have 6 earth taps that are 70 feet deep in a conical shape that all join at the manifold. Two lines run inside the house to the air handler and the system uses R22 refrigerant. I only had an area about 10 feet around disturbed in the front yard with a small trench running to the house for the installation. It cost me a bit more because I had no air ducts run in the house before the geo system. The money I saved in the cost of the oil we would have used in the last 5 years has paid for the system. It also makes all the domestic hot water and the only time it kicks into 2nd stage is when the other half takes an extra long shower right when the heat comes on. The system gives priority to the hot water and the stat will kick in the electric element after 45 minutes if the house doesn't hit the set temp.

Here is a link for more info on the Geo company.
http://www.advancedgeotech.com/techov.html

I had thought about a geothermal system, probably the cheapest, is a rectangular hole. You dig down 6 feet maybe 12 by 24 foot trench. You just layer the bottom with plastic piping, and fill her up with dirt. Done. I'm sure the the location and terrain will determine the efficiency.

[GeoffBoyes]

Hey I also have a geothermal hot water system, and I need to advise everyone who gets one to watch the installation. It uses the surplus heat from the air conditioning freon, to heat water, which is circulated through the heat exchanger. the problem was that the installer simply hooked it up to an 80 gallon electric hot water unit. Well the crazy fact is that when I shower at 5:30, and pull down the hot water, the cold water entering the unit is quickly heated by the electric element to 130 degrees, and by the time the air conditioner starts operating at 12:00 am and the afternoon, to provide all that good free hot water, the water entering the exchanger is 130 degrees. So the unit says, sorry, thats as hot as I am alowed to heat water, go back to the electric hot water tank. SO,,, you get NO effective heating unless you are pulling water when the air conditioner is operating, and even then the electric elements will heat much faster than the heat pump. So I got an old 80 gallon hotwater tank and installed it as a "storage tank". The cold water enters this tank, there is no electric elements in it, The water constantly circulates until the whole tank reaches 130 degrees. Now when I take a shower, the electric hot water unit is replenished by 130 degree water from the storage tank. I am looking forward to seeing how much my electricity bill will drop, as I have only just completed this project, I am totally amazed that the manufacturer would not insist that the unit be installed with a holding tank, as the system I had was totally useless. Needless to say I cool the house for under $200, and my neighbors are running up $400 bills for the same size house. Its maintenance free, had it 3 years now. No noisy compressors outside, greatest thing since sliced bread.

[gdgraham]

I agree with your setup as that is how we generally install our units unless space or money is an issue. Here in Canada they work great in the winter even with one tank as the desuperheater will generate heat while the heat pump is heating your house all through the frigid night.

[gdgraham]

Quote - "I had thought about a geothermal system, probably the cheapest, is a rectangular hole. You dig down 6 feet maybe 12 by 24 foot trench. You just layer the bottom with plastic piping, and fill her up with dirt. Done. I'm sure the the location and terrain will determine the efficiency."

There are a lot of factors when designing a ground loop. Six feet is typically sufficient for depth but you will need a lot more area unless you live in a shoebox. Typical sizing for equipment in Ontario is 2 tons of capacity for 1000 square feet of house (not counting basement) you might add a size if you have an old house, walk-out basement, or an extraordinary number of windows, or a leaky house. Based on that you would want 600 ft of 3/4 pipe for each ton of equipment capacity. Each roll needs about a thousand sqaure feet of space. As an example a newish 2000 sq ft house might have a four ton heat pump. This would require four 600 ft rolls of pipe. You could lay this out in a 40 by 100 ft area or perhaps a couple 300 foot trenches that are at least two feet wide, or a four foot plus wide 600 foot race track, you get the idea. Basically you don't want to undersize or underspace your loop, especially for heating, or it will not be able to pull enough heat from the ground. Then your equipment will work too hard and eventually go poof. (Or at least repeatedly shut off if it has good self-protection controls built in.)

Cheers,
Geoff