Geothermal heat pump: first winter results

[truckdiagnostics]

Lets run some numbers based on what has been mentioned here. I believe people are being up sold because of the rebates and with the rebates geothermal will be the same cost. Lets start with the heat pump that Mclawn put in, he has $6,000 into it, for a compressor and an air handler with evaporator and chances are back up electric grid already in the plenum. The 500R11 from water furnace i bought used for the shop 12 years ago paid $4,000, $2,000 to bury the loop, $1,000 for the load center and $1,000 labor to install. That is $8,000 that unit has never broken down! so you then throw in the $2,000 he has spent in repairs then count the rebates. It comes up to be cheaper. Now lets work his backwards based on what we know. we are going to leave the air handler there. Take the compressor out and evaporator out of plenum. now we have the space for the water coil, already has the back up electrical grid. Don't know what he has for space. He lives in Mississippi not below freezing that much. has space for the compressor and was able to run the AC lines. I am going to Put water furnaces 500RO11 outside where the compressor was, run the water lines same way AC lines where run. may have to run larger AWG wire to the 500RO11 sometimes don't have too. All done, there will be antifreeze in the water lines so it he looses power, everything fits. Should be able to do for $8 to 10 then take in the rebates..... However knowing what i know about Mitsubishi's mini splits for mclawn's area I would be looking long and hard at one of them!

 

[MacLawn]

Thanks again guys! Truckdiag, the place I want geothermal is Georgia, just a bit warmer than where we also live in Mississippi (don't try living in two places at one time!). Georgia place is where we will retire. My current Carrier heat pump (we have NO gas at our place) is 3 ton, geothermal man said a 3 ton Water Furnace 5 Series Dual Capacity (whatever that means) is what he would install. He showed me where to connect the pipes, one inlet, one outlet pipe on my current water heater since I told him I can do that plumbing work myself. I have plenty of room in my crawl space for the unit he said. The unit in the crawl space would be about 15' from the current plenum and coil that feeds into the ducts. House is 1,800 square feet of heated/cooled space, ducts already in bathrooms, closets, etc., so the mini split systems wouldn't be good to heat/cool like my current duct work does. I do want to talk to some local people who already have this in my area to see how they like it.

 

[truckdiagnostics]

Thanks, the info that I got pretty much collaborate what you just said. As for an open system, there are a few reason for going in that direction. The property is mostly solid rock so horizontal loop is out of the question and tests that were made not far from where I'm building has shown to have more than enough water at 125 feet. I like the close system as it should be less cost maintenance, but the open system should be a little more efficient which in my neck of the wood is important.[/QUOTE
Makes sense what is often over looked is the discharge side, they freeze up. I have seen it where they will take out of potable water well and dump into shallower well. If your using well water you will never have issues with loop sizing, long as unit sized correct it will work slick, be real effecent

 

[techman]

Thanks, the info that I got pretty much collaborate what you just said. As for an open system, there are a few reason for going in that direction. The property is mostly solid rock so horizontal loop is out of the question and tests that were made not far from where I'm building has shown to have more than enough water at 125 feet. I like the close system as it should be less cost maintenance, but the open system should be a little more efficient which in my neck of the wood is important.

If you have ground water at a reasonable depth, vertical bore holes with closed loop pipes can be a compromise between horizontal and open loop. Only negative is drilling costs may be higher since you may need 3 or 4 holes.

paul

 

[truckdiagnostics]

Mclawn, sound like what he is putting in is unit like what is in my shop, if that is the case it supliments current hot water when unit is running, your area with the ac running more would be good choice.

 

[fordmantpw]

Would you be kind enough to elaborate on this statement? We are planning are new house in a year or so with Geothermal, water well and a hydronic system ''slab on grade'', and of all the research I did in the last 3 years this is the first time I read someone suggesting that (geo in extended cold period would not be recommended.) Don't get me wrong, I am not challenging your statement, just want to learn more from experience people.

Really, it's just a hunch. I have no specific data to back it up.

In our current home, during really cold periods, the geo runs a lot. I mean, 20+ hours per day (our thermostat tells us how long it runs and at what level). Now, it does keep the house warm, and it does NOT cost a lot to run it. It just runs a lot. Part of that is the fact that we have 5 zones in our 2500 sq. ft (on the main level) home (2 zones in the basement, 3 zones on the main level with one being a 'sun room' with tons of windows). Geos are meant to run a lot to move lots of air, I just feel that it would not be preferable to have it running that long for extended periods of cold weather.

We have a WaterFurnace 7-Series (top of the line) with variable compressor and variable speed pump. On our thermostat, it will tell us the level that the heat runs in. It never ran above level H1 (the lowest level) then entire winter, and the aux heat never kicked in. Our highest electric bill was only about $50 more than our last bill which had essentially zero climate control expense on it.

Again, just a hunch. As others have noted, it's probably fine as long as it is set up correctly (and I feel ours is). I just think I would like to have wood or pellet for main heat in an area with regular sub-zero temps.

 

[Redneck in training]

Our geo HP also runs almost constantly during very cold sub zero days. Since we live in the sticks and might have power out even for a week every few years (due to ice storms) we have two propane fireplaces that we could use if the HP wouldn't be able to keep the house warm.

 

[Henri88]

Again, just a hunch. As others have noted, it's probably fine as long as it is set up correctly (and I feel ours is). I just think I would like to have wood or pellet for main heat in an area with regular sub-zero temps.

I had a chance to meet with one of the rep. from our New Brunswick Power Commission about a month ago (expert on energy saving) and I told him about the system I wanted to use including a pellet stove for back-up. He jump right in and told me that the geo system will cost a lot less to operate then the pellet, no matter if it was a stove or a furnace. I agree, with you guys,the trick is to have the right set-up and installation. Thanks!

 

[Henri88]

If you have ground water at a reasonable depth, vertical bore holes with closed loop pipes can be a compromise between horizontal and open loop. Only negative is drilling costs may be higher since you may need 3 or 4 holes.

paul

This is the exact reason why we decided to go with the open system and further more, I am looking at having the well directly inside my house garage where my geo pump will be install but I have to do a lot more due diligence on this.

 

[MacLawn]

Henri, I think ye man up there is right about geothermal costing less to operate than pellet stove, which also needs electricity. A friend bought a pellet stove 3 years ago, he's in south like me, and it costs him over $350.00 a winter, plus he uses heat pump and a fireplace insert too. And, you have to store the pellets in a dry place.

Anyway, from wha' I'm reading about what y'all boys say, it seems proper installation is the most important thing.