ICF house

Ken_40

Which is half ICF's and half SIP's, I'd urge total separation of heating and A/C.

This is very dependent on heating vs. cooling requirements. Where we built, there were five days when the inside temps this summer were in the mid 80's indoors at 9 p.m., that A/C would have been of some comfort.

Winter runs to 30 below zero too often to dismiss as "anomolies". Simple radiant, is not the answer. Slow response times are common, the major glaring weakness of radiant-only heating. A crefully designed HWBB AND radiant system is THE ultimate solution to comfort, energy savings and uncluttered designs.

We have never seen a geo-thermal system ever approach energy savings and comfort levels a well designed alternate system could deliver; with the sole exception of those geo systems installed in areas where it never freezes, and never goes above 90. Humidity control being the primary function of A/C, the need just isn't there as universally as the marketeers of geo suggest.

Or is it?

Heatman_2

ICF house

I'm bidding on a 2 story concrete house with walkout basement, 5,000 sq. ft. finished. Homeowner wants in-floor radiant throughout all 3 floors.Slab over grade in basement and gypsum overpour on other 2 floors. Air conditioning is a must(customer wants Unico). This house sits on 28 acres, so geo is an option, and homeowner has yet to be convinced on best heat source. What do you guys think would be the most comfortable, yet economical system

Brad White_120

You would need to know

which fuel/energy source is both the lowest in price and the most stable in price and availability for the area. This can vary widely with local distribution charges, wellhead charges for gas or oil, taxes and all of that.

Then whatever you choose, use it wisely and efficiently against a lifecycle cost analysis.

If you have electricity as your heating source then Geothermal with a high COP (4.0 or better) can be attractive if the rates are reasonable. Winter rates might be lower too. Gas for ModCon boilers is hard to beat for fossil fuel efficiency.

Too many variables. Talk to your local energy suppliers to establish rates, rebates, incentives too.

Heatman_2

ever installed a water to water ground source heat pump, providing radiant floor heat during the winter and cooling to a Unico water coil during the summer. I had planned on 2 Unico air handlers, is this possible?

Unknown

icf house

we did a similar project about 3 years ago: 3 floor home approx 3000 sq ft. total, geosource RIF, all concrete ICF walls, no cooling though i'm afraid.

owner reports $65 p/mo heating costs in middle of winter. (our elec rate here is .06 cents per KWH mind you) you can't beat the comfort of in-floor either. not much heat loss/gain with ICF blocks, perhaps radiant cooling is in the cards on your project?

Brad White_121

No installations

for I am on the design side of things, but have designed several similar systems. Too complicated to explain in a short forum but the short answer is to make sure your earth medium/area is sized for the worst case. Most of the systems I have designed or had experience with were deep bore well types but the principles are the same.

Yes, it can be done when producing conventional chilled water. The number of air handlers does not matter so much as your load. As for Unico/Spacepak though, I have never used those with chilled water, only DX. Not sure how cold a chilled water source you need to get the temperatures down to those ranges. If like refrigerant you need SST's in the mid 30's, you may be looking at brine if you go the water route. I do not really know.

Craig R Bergman

You're not looking then...

We did a 7,300 sqft home plus a three stall garage with radiant floor, chilled water coil Air Handler and twin Water to Water GeoThermal Heat Pumps. Last February it cost them $147.00 to heat the home and keep the garage at 55*. When properly designed and installed, there is no fossil fuel appliance that can compaire to GeoThermal.

We are located in Cedar Rapids, Iowa where it does freeze and it does get above 90*. The electric rates are about 9 cents/KwH.

Craig R Bergman

You're not looking then...

We are located in Cedar Rapids, Iowa where it does freeze and it does get above 90*. The electric rates are about 9 cents/KwH.

We did a 7,300 sqft home plus a three stall garage with radiant floor, chilled water coil Air Handler and twin Water to Water GeoThermal Heat Pumps. Last February it cost them $147.00 to heat the home and keep the garage at 55*. Up front costs were a little over $10,000 more than a Mod/Con & Outdoor Reset. Payback on the system is 4.6 years!! When properly designed and installed, there is no fossil fuel appliance that can compare to GeoThermal.

Bergy

John Mills_5

High Velocity?

Why do they want SEER killing Unico in new construction? For likely less money, they can go conventional with a variable speed air handler, have higher efficiency, low speed low cost constant fan, can have dehumidfy on demand, easy zoning...

Heatman_2

Is it possible to use panel rads in carpeted rooms with this kind of app. I didn't know if geo could generate hot enough water for the rads?

Craig Bergman

Best temps

I not sure about panel rads...
The best water temps with Geo are 120*. We can go higher but the system efficiency starts to tank (fast). Our worst case has been about 1,500 BTU/hr supplemental needed, so we ran some tubing in the walls.

Bergy

hvac-tech

back up unit

what is your back up heating unit?

Craig Bergman

Most radiant homes

we do, have twin Geo Water to Water units. One is heating and cooling the other is heating only. The H&C unit is second stage heat.
If something were to happen to the primary unit, the second unit takes over until the first is fixed.

In homes with one unit we wire the 50 gallon electric buffer tank to come on if needed.

Bergy

hvac-tech

back up heat

one ele. water heater to heat a home ?

How do you heat DHW with geo thermal?

Craig Bergman

Desuperheater

Rather than dump all the heat into the ground it is put into a buffer tank for domestic use. During the heating season the Geo will give some DHW in first stage. When the unit goes into second stage, the Desuperheater is shut down and all the heat goes to the home.

Bergy