geothermal questions and possible DIY

[mikester]

Open loop is the cheapest and would be more efficient in the short term looking at day to day operational costs in kWhrs. My neighbor ran his well dry and had to spend $10K drilling a new deeper well with enough flow to keep up with the furnace requirements. Not saving any money at that point.

My cold climate ASHP's have been working for me down to -30oC. Thankfully we don't get that cold for long periods of time.

 

[Sigarms]

Never oversized if you want the cooling to actually do it’s job correctly. It is intended to dehumidify not cool. Dehumidifying is achieved by long run cycles

Biggest bunch of BS in all of HVAC. Especially when you consider modern 2-stage and variable-speed systems.

LD1, I agree 100%, the issue however isn't dehumidification, but the actual heating load.

Even west of 95 in NC, if you require 24k of cooling at 95F OAT, you will most likely need 24K of heating at 20F OAT.

I have single and two stage systems with variable speed blowers in my own home. You want lower humidity, the only good way to do that is with a whole house dehumidifier tied into your system.

 

[coolconnection]

Just be careful what unit type/brand you buy. If it has copper heating and cooling lines for the heat exchanger you will be replacing it in 5 years or so. Freon does not like copper and it will erode the copper eventually and put pin holes in the systems copper lines. Some manufacturers brag about they coat the copper inside now so it does not do this but I have my doubts. Mine did, HVAC guys couldn't believe my unit was 17 years old. Said I had one of the oldest Bryant units they've seen. 30 year units out there, I don't believe it maybe 10 to 15 year units unless they paid the big bucks and replaced the heat exchanger once or twice. My new unit (made more sense to replace with new vs fix old and I get gov't discount) has aluminum coils so freon shouldn't eat them up plus it has a 17 year warranty. It is made in the USA by American workers by a company that has very high quality ratings and not any more or less expensive than other brands out there. I looked at them all and compared their quality ratings and read customer reviews. Time will tell.

 

[LD1]

The whole open vs closed loop debate....can't say specifically one is better than the other because each situation is unique.

Open loop on wells cheaper.. depends if you already have a well. Depends on how deep you need to drill.

Same goes for efficiency. If you have a good aquifer at 30-40'......open source may indeed be a viable option.

If you have to drill a 300' well... Not only is that expensive.....but the energy required to pump water from that depth quickly start eroding any potential efficiency benefits vs closed loop.

And closed loop can control water quality so you don't start building scale inside the exchanger, further reducing efficiency

Personally, I'd never consider open loop in my area. And efficiency can be gained by simply oversizing the loops. (More loops ,or longer loops).

 

[dodge man]

Just my opinion, but I think closed loop is better. In my case they directional bored the underground lines in. In other words they were’t open cut, the ground was disturbed only where the lines went in the ground and where they looped back. The problem is you need space for this. I live on 3 acres so I had the room. I’m not sure the footprint in needed but roughly 300 feet long by 60 feet wide.

Humidity has never been a problem for me But I also run a dehumidifier in our basement which I assume helps.

 

[LD1]

Just my opinion, but I think closed loop is better. In my case they directional bored the underground lines in. In other words they were’t open cut, the ground was disturbed only where the lines went in the ground and where they looped back. The problem is you need space for this. I live on 3 acres so I had the room. I’m not sure the footprint in needed but roughly 300 feet long by 60 feet wide.

Humidity has never been a problem for me But I also run a dehumidifier in our basement which I assume helps.

If you strictly want to talk about efficiency......and not the other cons associated with other loop types, then DX is actually the most efficient loop type. No water, no heat exchange medium, and copper is exponentially more conductive of heat than plastic

 

[copytmpmzl]

Yes, This is actually my thread from 9 years ago when I was contemplating doing my own geothermal. Which I did end up doing.

To say that it uses around 25% of the power of a "regular" HVAC system all depends on how you define a "regular" system.
A system that heats with wood, propane, fuel, etc actually doesnt use much "power". And how the costs compare can vary widely year to year.

If you are talking about comparing geo to a regular air-source heat pump....then above 40 degrees outside temp there is actually little difference. Geo doesnt really start showing significant improvement over convention air-to-air until the temps start dropping. So if you live where there is mild winters....like TN or NC not much savings and longer payback. If you live in Michigan or Montana....big difference. An air-source will be limited and youd be relying on some other form of heat most of the winter.

Now if you are talking about electric resistance....like baseboard or radiant or electric furnace..... geothermal is indeed about 3x-4x more efficient epoxy flooring gold coast. Simply meaning that for each kwh of electricity you buy....you only get 3414btu's of heat out of electric. But if its geothermal....that same kwh of electricity can buy you ~12,000btu's of heat.

thank you so much for your suggestion

 

[buckeyefarmer]

If you strictly want to talk about efficiency......and not the other cons associated with other loop types, then DX is actually the most efficient loop type. No water, no heat exchange medium, and copper is exponentially more conductive of heat than plastic

I went to 1 job site where a company was installing a DX system, copper Freon pipes 40 ft on the ground.

 

[dodge man]

I know all the runs on mine are some kind of plastic pipe. I’m not sure what all the piping is inside the Water Furnace.

 

[LD1]

I know all the runs on mine are some kind of plastic pipe. I’m not sure what all the piping is inside the Water Furnace.

DX is is directly burying the copper freon lines in the ground. Rather than using water circulation to convey the heat into the furnace then transfer it to the freon via heat exchangers. The compressor directly circulates the freon outside. Basically making the ground outside be the best exchanger.

It's simpler, no water plumbing and water pumps. But concerns of the longevity of the burried copper....and overall the system holds more freon.