My question here is about Geothermal and specifically DX Vs Reqular

I have read the primary differances between them is that one circulates a water/anti-freeze mix thru a plastic type pipe and then exchanged into a refrigeration unit. The DX is basically an extension of the refridgeration unit into the ground

What are the benefits and disadvantages of either. I am finding it hard to get information about the DX system. I guess my primary concern is the life of the copper pipe in the ground..?

Which is the more commonly used system.?
which is the better system..?

Can any installer install either one..?

I would really appreciate any information on this topic as i need to make a decision pretty soon. Are there any sites that have more information on this topic..?

thanks in advance to everyone

Vin

SR

Assuming neutral PH, What is the expected life of the copper in the ground..?. Is this something that one should expect to replace after 10 or 20 years. ?

What is the impact of a refrigerant leak into the ground? is this of the same magnitude as an oil leak interms of impact to the envirnoment, or is the refridgerant less toxic. I have heard that it evaporates, however how can that happen 100ft down..?

Copper is still the ‘gold standard’ in plumbing. How often do the cold water mains into your house have to be changed, every 50 years, give or take? Why? Usually not because of corrosion, but because of restricted flow caused by a buildup of mineral deposits.
DX ground loops should last 50 – 75 years. Should the refrigerant leak it’s probably more of a hazard to the atmosphere than to the ground or ground water. The liquid anti-freeze in a conventional geothermal system would likely be more harmful to the ground and ground water than Freon. An oil leak, if sever enough, could be a catastrophe both environmentally and financially, which is why we moved away from our oil furnace.

I don’t loose any sleep over our DX ground loops. The whole system has been surprisingly and absolutely trouble free! I kind of view the whole controversy as somewhat akin to the debate of, ‘which do you prefer, PC or Mac?’ Personally I prefer the Mac.

In the link below, the top picture with the blue drill rig was taken in our front yard next to a flowerbed. The drill bit sticking up out of the ground is the size of the borehole, only 3 inches in diameter. The entire ‘bore field’ is not much larger than that patch of grass in the picture. This company did not do our installation, but ‘lifted’ the picture from elsewhere on the net.

SR

How does your system manage with the home hot water needs. Do you need an additional water heater? or will the system generate enough hot water for a family (Kids baths, showers etc etc)

thanks

The year before we installed the GSHP, we installed a stainless steel HW tank that has turned out to be incompatible with the HP desuperheater due to an internal cold water-mixing valve that reduces the tank’s stored water temperature from 175ºF to a nominal 120ºF at the tap.
The bottom line that anyone should be able to relate to is our home is 2400 Sq. Ft. with 4 people, in Montreal Canada (cold winters & warm, sometimes hot summers). Our only energy source is electricity and our total electrical consumption over the past full year was 18,038 Kwhrs.

SR

We are preparing to build our own home and have started looking into this DX system. It will be in Ottawa - so same as you, cold winters and hot summers (really humid days sometimes). Can the system actually cool your home during the summer? How good is it compared to a regular AC unit?

Thanks
Joseph

The system works very well in the A/C mode – even on the hottest days and is probably 40–45% more efficient than either a standard air-conditioner or air source heat pump. Imagine it this way; instead of dissipating the heat from your house into the hot, humid air that may be 28ºC or higher, you’re dissipating it into the cool ground, which is about 6ºC (close to what it’s been the past few days). Also, you do not require that big noisy fan found in heat pumps or air-conditioners; the cool ground is doing all that work - free! Instead of half your system sitting outside baking in the sun, the whole system operates indoors, in its own air-conditioned comfort. Putting you hand on the heat pump cabinet in the A/C mode is like opening you refrigerator door and touching an inside surface panel. It’s actually quite brilliant.

If you send me an e-mail through Garden Web, I’ll put you in contact with the right people in Ottawa.

SR

We are going to sell a green built condo. There is tons of development here but it is mostly driven by developers seeking to double their money and not interested in better building envelopes.

My realtor says no one cares about that sort of thing when they buy but I can't see building a place any other way.

Your realtor lacks the vision to see a future beyond his next commission check.

Are you going to sell one condo unit or many? Is this your first borehole that at 80 ft. you’re ‘running sand and boulders’? That sounds rather strange. I would expect you’d be into solid rock long before that. Scrutinize your driller’s credentials more closely if it’s not already too late.

Since you are having real difficulties or even perceived difficulties, I would suggest proceeding with caution. Consult detailed geological maps for your specific region, area and location to determine with as great a precision as possible just what exactly is down there. This information does exist and is worth seeking out; the US Geological Survey might be a good place to start.

I would go with a conservatively designed HDPE/liquid system. Something anyone specializing in geothermal can troubleshoot and service. The last thing you want to hear, should you later have any trouble is, ‘why didn’t you go with something more conventional?’

Last, but probably first, I would want to talk to an IGSHPA certified geo-exchange designer in your area. That’s the person who will likely have all your answers. They will likely be a professional engineer as well.

Good luck; keep us posted.

SR

I'm just now starting my research into this system (I had never heard about this before until recently).

Thanks
Joseph

Yeah it's 75 to 80' before you hit bedrock. Apparently it used to be the ocean here 65 million years ago. I could see the senario where there is kind of a water table on top of the bedrock.

I did do a little research and I even told the drillers before they showed up but did they listen? No. They just figured they would come out and see for themselves.