Undersized geothermal system?

[jab490]

So the final decision was to go with foam in the roof and 3rd floor but batt insulation everywhere else. This was to eliminate the need for mechanical ventilation. Hopefully this compromise will find the sweet spot between being tight enough to hold the comfort of the house but not so tight that we need a dehumidifier or mechanical air exchange. Also, with the mechanical air exchange, the cost of foam was getting prohibitive.

As for the water, it gets pumped back into the well and is used like any other well water (eg., bathing, drinking, washing). The water isn't contaminated by the HVAC system. Still, the state performs a yearly test of the well to confirm that the water is safe.

Does all of this sound reasonable? Thanks for your input.

[mikeweber3]

Jab,

I question the wisdom of using one system on a 3 story house. Are you putting in a zoning system?

Mike

[crash11]

So the final decision was to go with foam in the roof and 3rd floor but batt insulation everywhere else. This was to eliminate the need for mechanical ventilation. Hopefully this compromise will find the sweet spot between being tight enough to hold the comfort of the house but not so tight that we need a dehumidifier or mechanical air exchange. Also, with the mechanical air exchange, the cost of foam was getting prohibitive.

As for the water, it gets pumped back into the well and is used like any other well water (eg., bathing, drinking, washing). The water isn't contaminated by the HVAC system. Still, the state performs a yearly test of the well to confirm that the water is safe.

Does all of this sound reasonable? Thanks for your input.

You're pumping back into the same well?!?!?!

[merken1]

Jab,

I question the wisdom of using one system on a 3 story house. Are you putting in a zoning system?

Mike

I agree, you need two system in order to have a comfortable temperature range in side your home. If you go with the two systems approach you will elimate future headaches. Duct zoning system will work, but are complicated and you will need to have a good service company to handle your service. I never found a good zoning system or at least every time I did the company would go out of business and parts became scarce.
I'd talk to your contractor about putting in a condenser in the loop to allow the A/C unit to run on a closed loop system and the well water to run through the remote condenser on an open loop.
I had a Florida Heap Pump system in my home in Charleston SC and the condenser on the first floor would only last for 4 years before fouling up. I used the Copper Nickle condenser system but the problem was the fouling by the sediment in the well water. I was going to install a plate heat exchanger in the condenser loop, but sold the house instead. Good luck on the house

[merken1]

Jab,

I question the wisdom of using one system on a 3 story house. Are you putting in a zoning system?

Mike

I agree, you need two system in order to have a comfortable temperature range in side your home. If you go with the two systems approach you will elimate furture headaches. Duct zoning system will work, but are complicated and you will need to have a good service company to handle your service. I never found a good zoning system or at least every time I did the company would go out of business and parts became scarce.
I'd talk to your contractor about putting in a condenser in the loop to allow the A/C unit to run on a closed loop system and the well water to run through the remote condenser on an open loop.
I had a Florida Heap Pump system in my home in Charleston SC and the condenser on the first floor would only last for 4 years before fouling up. I used the Copper Nickle condenser system but the problem was the fouling by the sediment in the well water. I was going to install a plate heat exchanger in the condenser loop, but sold the house instead.

[Air Tight]

Original post was in March. The system is probly in already with the schedule he gave. I also wondered about the multi stories and single system not zoned. What really caught my attention was the difference in load cals from NC to ORE. His calcs were so close to even "lol" ours here are like 107k loss to 88K gain and we're way dry, no latent. Always learning on here.

[2nu2no]

Even the Bismarck sank! , Redundancy, beak it up 1st floor an independent zone, then 2nd & 3rd a zoned second system.

[2nu2no]

Phosphates in a Geo are you kidding

[Air Tight]

ROFL 2nu2no. I was lokking at your avitar and at 1rst thought it was black trash bags at 2nd look. I thought No, it looks more like black fish. Then I realized it was the mid section of a motor cycle. Time for an eye test I guess.

[2nu2no]

GSX1300BK it's 181.5 hp @ the crank or 163-165 hp @ the rear tire

[Air Tight]

Right on it sounds like a sweet bike. I told my wife I need to get a another bike. It's been awhile since I've had one. She said ok as long as it has a side car for our daughter and she rides on back. She almost killed me when I expressed, That would defeat the whole pupose of getting a bike and the one I get won't have a passenger seat.

[2nu2no]

the wife will never ride this one, she likes the Ultra Classic

[alex_in_fl]

I have been installing and servicing geothermal now for about three years. the company i work for is the biggest geothermal installers in central PA
A few questions i must ask:

Why are you going open loop?
What we have found is that the open loop system needs to have more flow then closed loop system due to the loop water and not being able to take advantage of an antifreeze. which brings up another problem what happens when temp. gets below freezing? even though the loop will be below the frost line (and since you are going with wells it is a better advantage) But pulling up ground water will bring in sediment which is going to plug your coaxle coil quicker then a closed loop would. and another problem with open loops or pump and dump is what happens when north carolina has a drought which occurs often in the southern climates. (i have a sister that lives in creedmore NC which is close tothe durham area.

Another good note to think about is each ton should have around 200 ft per ton or for every 1200 btu

First, if you are going open loop then you don't have to really worry about loop size. You simply need to insure that the inflow and return wells are as far a part as possible (at least 50 feet). If you can have them at different depths that helps also. Do make sure to go deep enough to avoid drought issues.

Redmontech: Your post confuses me on several fronts. You state open loops need more flow because they can not take advantage of antifreeze. Everything I ever see is that the antifreeze has less heat transfer than water and requires more pump power too. This should mean that an open source unti would require slightly less flow - not more. Can you explain your logic or why your company is seeing the reverse of what engineering predicts and most other companies have found? Thanks.