Has anyone used or research geothermal heating systems to heat their homes? I have a friend that is considering it and would love to hear from people who are using or have considered this type of heating.
"Geothermal" is heating with underground hot water. This is very rare, and usually requires very deep drilling, except in a few areas where there is hot water near the surface.
However, in many areas, you can drill down into the ground and take heat away and in the winter, and supply heat back into the ground using a "ground source heat pump" system. Or, sometimes horizontal trenches are dug and pipe laid in them for the heat sink. Or, sometimes a lake or the sea can be used - you arrange some coils of plastic pipe in the water, and do the same thing.
The cost is the key. Find out if the heat transfer characteristics are correct from a proper well-driller-installer of ground source heat pumps. If your area is OK for this, then go for it. There is a capital cost, and you have to decide if you like the idea and the long pay back.
If you decide to go ahead, then you need, a well(s), a pump system for the water, a heat pump, a buffer tank (usually), a peaking water heater (usually - an economic decision), then an air distribution or water distribution system.
Particularly interesting in the "slide show" are some unique small fan coil units that successfully operate. These are Canadian made and work well. These units will cool and heat. You can use a more common air distribution system for heating and cooling, or a common in-floor radiant for heating only - still all of these use the other basic heat pump equipment and ideas in the slide show for this project.
Boring (not for me) Calculations
The "heat transfer" Heat transfer calculations information I talked above are some of the terms shown in the typical calculations on this link. Your local supplier should make these calculations and you should ask for a copy to review.
There are installers who specialize in most areas in small (and larger) single family residential ground source heat pump systems and can help you figure out the cost and pay back. Or understand the cost connected with your desire to help use less electrical power and/or be more energy efficient.
I think using a GSHP is a good idea, and heat can usually be had for about 1/4 of the cost of electrical power (depending on several things).
Zero Energy Use
The idea of having zero net energy use is greatly helped by highly efficient system like these GSHP systems. Once we get our energy use very low, then with solar voltaic power generation (and other renewable ideas) we can have at least a zero-connected-to-the-grid-energy-use-house. The cost is more, maybe $18,000 for a big house, and the pay back is real long. I am not talking about not being connected to the grid - use the grid - just don't use ANY energy that you do not generate.
And, what about a granite counter top - every new place in Vancouver and San Diego HAS to have those tops. They are not "cost effective" - people pay a lot extra for them because they want them or MUST have them. What's the difference with just having to have a "net-zero-energy-use" house.
Most of us can live with zero energy use. Are we strong enough to do it? Will we pay for it? Even if it cost more than not doing it. Wouldn't it be great to live with zero net energy use, day in and day out, every day, everyone?
I agree with your vision Alex, "0 net energy use"...especially for those of us living in colder temps (or very hot temps for that matter).
I would be very interested in implementing a system as you said where you use a GSHP system and run the pump with solar energy.....possibly all energy use off the grid!
Bergere: Thanks for the offer, and any other resources would be of use for us all to learn. I find you never really hear about geo temp control when people talk about renewable energy sources? I personaly don't see a disadvantage other than the initial co$t.
I have a ground source heat pump and it is 14 years old. I have been extremely pleased with its performance. Heating and cooling are terrific but the best part is the low cost of operation. I have never done the calcutions as to its return on investment but I do hear my friends discuss their excessive heating and cooling expenses and I do not participate in the conversations since none of the discussion applies to me. They would not believe how cheaply the device works. The unit I have is a water exchange but I regret I did not go with a loop. The next one will be a loop. My costs to have the unit installed 14 years ago was cheaper than a conventional heat pump. I like the fact that there is no external condenser unit so there is no rusting of the cabinet and its contents. The exchange unit is also very small and is more like a refrigerator than a heat pump. It should easily have a 20 + year life.
I am palnning on using a closed loop geo heat pump in oue house when we build in spring of 05. I don't want the propane expense. I am a HUGE DIYer and therefore refused to pay 14000 or more for an installed system and that was with me doing the excavating. After exhaustive searches I finally found the answer to my prayers. A do it yourself set up available to the public @ www.arit.com This is what I will use.
We have been talking with an HVAC guy about installing this for our new home and it's going to cost us some where close to $20k for a five ton unit. (Average 1 ton per 800 sf) This will heat and cool our 2600 sf home for pennies compared to any other system out there. We were told that there will a series of five to six pipes installed six feet under ground, with a trench 3 feet wide, 135 feet in length. Each pipe needs to be a minimum of three feet apart. Pipes are filled with a fluid type material that won't freeze, under 5-10 pounds of pressure. Other details are too hard to explain with my pea brain!
It may be a more expensive unit to install, but over the life of the system, it will out perform any other conventional system for a fraction of the costs.
If you are a DIY'er, check out Ebay for heat pumps and plastic pipe. The last time I looked there were lots available. There were some systems complete except for water storage that were around $4K.
I'm going to install such a system about the same time as you. The biggest deterent to a closed loop system is the digging. Fortunately, where I plan to build, the previous house burned down leaving a basement that I plan to use instead of digging the trenches. Since the cinderblock is no longer structural, I plan to just lay the pipe and cover it up before I add a new foundation to the site.
I'm convinced you can beat the costs above by nearly a factor of 10!
I will be using something called 'ground tubes' in the house I'm renovating. It also involves pipes laid underground but the air is pulled in through one end, circulates underground (which cools it) and then comes in the house.
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