this is most energy effecient method of heating and cooling- just a bit pricy if you need to drill a well to bury the loop.

If you have a pond/lake that you can use a the heat sink, your're looking at a much cheaper install and maintance.

What's the project's location - are your mostly looking for cooling or heating? not much differences, but may impact the size of loop needed.

The location is in Canada.
I've got three options:
-lake loop
-ground loop
-drilled well loop

I'm now determining if the well has the flow required to piggy back this system on the domestic water system. If so, this will be the cheapest.
Either way, it will be up to the client, but she's shown interest in the possibility, and so far it looks like a 40-60% premium over a standard system (have to demo the existing furnace and ductwork anyway).

Whetever you've got to add, I'd love to hear it.

Thanks

The lake loop I thought would be the cheapest, but if you're drilling a well, then this provides a warmer source. The lake loop is great for cooling, but you may have issues with heating in the winter.

I've only read about ground loops/gotten presentations on the topic mostly for California cooling. Now with my move to Minneapolis, I need to read up on the heating potential. I've been discussing ground loops with one of my clients for a condo tower (plenty of shallow ground water on site that we'll be digging down to anyways) in LA- he has an interesting business patent on creating a private utility to spread the system's costs to all the condo owners ...

Now I'm fascinated by the idea of a cool beams for passive cooling (but the air needs to be dehumified first), this elimnates most ducts, and fans.

In Vancouver, Peter Busby has done some great projects with ground loops...

Does anyone have any experience using this system somewhere like Houston (hot & humid)?

What's your location in Canada? I've heard these residential systems (for heating) are gaining popularity and have shorter payback lead-times than down here in the states...at least in places like Winnipeg and Edmonton.

Treekiller - in MN the geo-thermal option is mostly an exotic thing where the cost outweighs the benefit. It just doesn't get cold enough and nat gas hasn't got expensive enough to make it popular.

The key to convection cooling (ie chilled beam, or chilled slab) is to dehumidify the air first so that condensation isn't an issue. Also, you don't cool the circulating water more then a few degrees below the desired temperature (same for heating only a few degrees above desired temp)- this is where half the savings come from, not having to over heat or over cool the air/water to impact the conditioned space.

In the SW, I've heard that often air heat exchangers are the primary method of heating since the number of cold days is too few to install a dedicated furnace, and the heat pump works great for cooling.

There are some great air/air heat exchangers that also deal with humidity through a descicant wheel (this has a really fancy technical name that I don't remember...).

Most of the installation cost is for digging/drilling the loop. with a water loop you don't have this labor- you just assemble the loop and float it out into the pond, once flooded, it sinks to the bottom. If you have any leaks or problems, fill the loop with air and it floats to the surface for easy retreval. Suprised this isn't cost effective in the land of 10K lakes!

I'm in Central Ontario. I've wanted to use this technology for a while, but until now the clients haven't been paying enough attention to the benefits. Of course, the additional cost is a hard lump to swallow, but long term savings are a good carrot.

Out of curiosity, in new construction, what is the difference in cost of a standard (forced air/radiant) heating system vs. geothermal heat pump for setup and install? Also, not mentioned was the maintinance associated with this technology. I've never worked with it myself, so I was wondering what was involved and what the costs were, versus a traditional heat source.

i'm working on a house in sanat fe that's going to have a ground loop system (hopefully).
We're in schematic right now and just got a rough pricing number that is about 50% over budget...urp.

I'll admit that I'm no expert on geothermal. Just every mech engineer I've worked with has said the payback just isn't there yet. Additionaly it is my reccolection that you need to have a back-up heat source in addition to geothermal - by code. So you don't eliminate the need for the gas/elec system. Can anyone verify?

System looks sound. I'd like it in my own house. No ponds though and not near the room for a horiz loop. How deep does the horiz loop need to go? Assume below the frost line, which would have me buring the things under 48" in MN. Imagine 60" in central Ontario. Much easier in the more mild climates.

Chili, based on my project, it looks like a 50% premium to go with the heat pump vs standard furnace. Add a small premium for the ductwork (higher velicities, I'm told).
The biggest difference, however is the source loop. Any of the options is expensive. In my case, we may be able to use the excess water capacity from the drilled well to source it. If the capacity is there, I expect the overall premium for the whole system will be about 25 to 40%.
In dollars, this probably represents about $6,000. Ofsetting the premium is the savings in fuel costs, which would likely be at least $100/month (5 years).
Admittedly, the payback is much slower if I need to do a dedicated source loop.

Note that all of this is from what I've gleaned from various online sources and my conversation with my supplier. I'd really love to hear from someone who's dealt with this on the design side to know what to look for.

Cheers

Freq - One more ?... Are you planning on using an open or closed loop in your system?

Chili
If the well has capacity, it will be drawn upon as the source. Once run through the system, it would be discharged (at a different temperature). I assume that means it's an open system.

Yes. And from what I understand, that is the cheaper route. A closed system requires antifreeze and water conditioners, and many chemicals are not allowed by state regulations.

We've used several applications of geo -- res and comm... You definitely need to get with an expert -- one that can show you several successful operational examples, so you can talk with a few owners. Payback is always an issue, but you can make it work FAR south of MN and Canada.
I'm always mazed how little water is in these systems.

If you do a well system.....you actually have to have two wells...one to pup out of and one to pump back into unless you have a creek or lake you can pump back into. Most of the time citys will not let you discharge into there storm sewer system nor their Sanitary Sewer System. You must have a certain distance between wells....think it is like a hundred feet. The Well depth and the well flow is also important to know before you jump into a project...and yup you only know what the well will produce once it it dug.....

I have an existing well with enough water flow to make it work but no where to discharge the water....it is a bummer.

Ground loop systems are used alot in Ohio....and it is cold there.

Oh... my well driller....has put in a system to heat a 35,000 sf house.
which in some parts of the house is calling for cooling (hand ball court)
while other parts of the house are calling for heat. Think they have 10 wells.

that's not a house- that's a cruise ship!