Geothermal Heat Pump

[tryan]

Jazz,

We went open loop on a lake front property we had built in 2005. Installer promised 7 year return ... year one, looks like ~10 years will be more accurate. My neighbor built at the same time and decided against geothermal (builder talked him out of it ... "won't work in Vermont") so we now compare heat bills every year. He ran around 3k for heat and electric. I ran around $1500. The added bonus is "free" central air. Had him in my house on a hot august day ... he was jealous.

Being open loop you need to wonder where the water goes. Into the lake for us. But don't let anybody tell you the ground will take it. You'll have a swamp. In the winter months it's like leaving a hose running 24/7.

The house has 3 independent pieces of geothermal equiptment: a water to water unit for hot water; a water to water unit for radiant heat for the basement slab; and a water to air unit for forced hot air and AC. Only the hot water unit runs year 'round.

Good Luck!

[travelover]

Quote:

Originally Posted by ERD50 ........Back On Topic: most of my yard is a septic field, the wells around here are getting drawn down and are very hard, iron heavy water - not sure I want to rely on that going forward (although I realize the water is being returned). Can they put these geothermal fields in and snake them through septic fields?-TIA - ERD50

If it works in a lake why not a cesspool?

[Texas Proud]

Quote:

Originally Posted by waltwill8 Texasproud, Forgot to mention, If you do wells, they need to be at least 15 to 20 feet apart to not interfere with each other. If you don't have at least 150 feet of easy drilling (no bedrock), it gets more expensive. If you go deeper, you need stronger pipe to take the extra pressure, and again, it gets more expensive. The only advantage to wells, is that the average temparature deeper is warmer (55 degrees where I live), so you need less pipe. Did I mention that as soon as the pipe is down the hole, they fill it back up with a grout around the pipes to enhance conductivity and prevent contaminating the aquifers?

Well, I have a 'standard' lot size... but not really, it is smaller because I am on the wrong part of a cul-de-sac... so, 125 x 65 or so... not enough ground... guess I will be going to the high efficiency unit when I replace...

[tryan]

I dodn't think your cess pool would generate enough "renewable energy" ... considering the source of the warmth.

My installers father is a builder in Canada. He explained a planned community he's designing which would be 100% geothermal. Miles and miles of tubes would be run in every conceivable space (no need to go too deep ... just run more tubing shallow). Then each house would tap into these common tubes and run a water to water and/or water to air unit; then pump the cold water back into the loop. Here's the kicker ... he charges a "utility fee" for access to the tubes. A timeless source of income and all he maintains is the tubes in the ground. WOW.

[waltwill8]

Jazz,

The ground loop was pressurized to 65psi when installed. My installer (he actually teaches electrician-ism and heat pumps at the local vo-tech school) mentioned that initially the systems had flow meters and pressure guages built in. Now there are sensors in the unit and it has a little led that blinks green if everything is OK. Otherwise, call him. It has blinked green for the last two years.

[ziggy29]

Quote:

Originally Posted by tryan Here's the kicker ... he charges a "utility fee" for access to the tubes. A timeless source of income and all he maintains is the tubes in the ground. WOW.

Well, the question is...how much is this "fee" relative to what one would normally expect to pay for "tube/loop maintenance" over the life of their unit if they had their own system? If the "markup" isn't too great, then the economies of scale could make it a good deal for everyone.

[Zathras]

No problem ERD, I also appologize, as I just continued the 'off trackedness'

Texas, most likely it could. However it would need to be vertical if you don't have room for horizontal trenches.
My contractor used the slinky method mentioned above. Each trench needs 100 ft in length for each ton of cooling and the trenches need to be about 8 feet apart.
The type of soil will tell you how efficient the system will be.
As for cost, my system cost about $8500 but my yard was in pretty much a perfect situation for geothermal.

ERD, I would guess serptic fields would be perfect as the temperature retention would be wonderful. I would want to talk to a couple of contractors first about doing it. My biggest concern would be the durability of the pipes/PEX used for the system in such an enviornment.

[waltwill8]

My system uses pipes of high density polyethylene rated 165psi and all joints heat fused together. The warranty is 55 years. The driller used these clips to spread the 3/4" pipes apart in the 4 3/4" bore for better efficiency. The grout tremie pipe holds everything in the center of the hole, and as the grout pipe is pulled out when filling, the geo pipes spread apart.
GBT Incorporated - Supplier to Geothermal designers, installers

[jazz4cash]

Went to the home show this weekend. Spoke to a guy selling the DX (direct exchange) type system mentioned by Samclem in post #4. Theoretically has some advantages including lower installation cost, but probably not cost effective untill current system needs to be replaced. Can't think of any disadvantages to this vs. the glycol type systems, unless you have a pond. I would be worried about glycol leaks. I downloaded 6yrs worth of utility bills and weather info and it seems our consumption has not increased as much as i thought, its the rate that are killing us. Our current system which is 8 yrs old was the last of the old tech systems with non-scroll compressors and SEER< 8. So hopefully when I am ready the technology will advance again. I also found an interesting technology at Welcome to Hallowell International: Home of the Acadia which is a sort of supercharged air-source heat pump that works in lower ambient temps. In the meantime, I am looking at dumping the electric hot water heater.

[tryan]

Update from VT ... my geothermal system had an R-22 LEAK in mid January. 10 days and a GRAND later the system was back up. The lesson learned: maintenance is NOT like a conventional system - down 10 days waiting for parts. Thanks to the wood stove, I didn't loose the pipes.

Guess it'll be 11 years before this thing pays for itself.

[cute fuzzy bunny]

The technology around now is pretty good, although the better stuff is really expensive.

The big problem you'll have is with installers. We put a new system in (not geothermal though) and it was a pain in the backside. A lot of hacks, scammers, part swappers and sleaze bags. And those were the guys leftover after I scrounged for recommendations, eliminated people with iffy BBB ratings and did a bunch of research.

I guess the good news is that some of the higher end systems, with the right control/thermostat (which these guys seem to want to fight tooth and nail to avoid installing) tell you about problems well before they cause problems. Mine uses a 4 wire serial bus communications net between the outside unit, the inside unit and the control panel and can detect refrigerant leaks, intermittent operation problems, increasing static pressure and temp levels at various points in the system like both coils.

The next controller up from what we got has a pager system built in and can call you and the maintenance company if it detects a problem.

[jazz4cash]

Quote:

Originally Posted by tryan Update from VT ... my geothermal system had an R-22 LEAK in mid January. 10 days and a GRAND later the system was back up. The lesson learned: maintenance is NOT like a conventional system - down 10 days waiting for parts. Thanks to the wood stove, I didn't loose the pipes. Guess it'll be 11 years before this thing pays for itself.

where was the link and what brand system are you using. I thought the freon side was pretty much conventional.

Don't forget you could have had a similar problem with an air source unit, but 10 days in not good.

[tryan]

Would have to pull the slip from the replacement part to get the exact part ... was seam that could not be re-soldered. So a replacement part was ordered. Came under warrantee ... but the installation and no-heat was mine.

Good news ... just spoke to my accountant. The Bush energy bill - passed a couple years ago - gives a 10% TAX CREDIT for geothermal systems. Looks like the return time just dropped to 8.5 years.

[cute fuzzy bunny]

Unfortunately that energy bills credits expired at the end of last year, and a filibuster stopped it from being renewed for this year. Might reappear by the end of the year, but I sort of doubt thats anywhere near the top of the political agenda right now...so I got bupkus for my install.

[tryan]

Wow ... that's a bummer. My install was done when the credits applied 2005-2006; wonder if that helps? Will see the accountant tomorrow.

[cute fuzzy bunny]

If its for last years taxes (year ending 12/31/07) then yes they should apply if your gear met the requirements.

They had a nice credit for tankless water heaters, high eff furnaces and high eff air conditioners. I got some kickbacks from Carrier that were about the same as the credits, so it seems the manufacturers are evening up the deal as required.

[tryan]

Ok, saw my accountant yesterday. $2400 (10%) tax credit will be rolled into next year. Didn't need it this year. This force me to file via paper (vice electronic); which is fine with me. Also said if I sell within 5 years a portion of the credit will be recaptured.

Pay back period is down to 8.5 years.