water to water geo +staple up radiant

jimbo_7

This is what I figure too. Add some photovoltic panels and you can take fossil fuels out of the loop altogether, no pun intended. What type of geo system do you have?

jimbo_7

Water to Water GSHP

Greetings,

Any professionals out there care to weigh-in on the feasibility of a design idea I have? I appreciate any and all input.

Location southeast NY state, roughly 1 1/2 hrs NW of the city.

Is it be possible (or have any seen it done) to use a water-to-water GSHP in conjunction with staple-up PEX radiant loops? That is to say, can these systems approach the WTs necessary to keep up with this climate's heat loss given this installation method? (95*/-4 ODT Summer/Winter w/ 75*/70* IDT Summer/Winter). Most manufacturer's literature stipulates 120* LWT but I have always thought that staple-up loops demand higher temps than that.

Hi-velocity air handler containing both chilled water and hot water coils would serve cooling needs and emergency heat (for quick recovery as floors warm up) respectively.

2-stage GSHP compressor could compensate for the inherently over-sized cooling load given the climate, operating only in low speed.

Could the work?

Thanks and cheers

Jim Franklin

Do the heating system design first

In general, that idea "may" work, but the right first step is to do a proper heat loss to see what kind of staple-up temperature you'd need to get the floor surface temperature to deal with the heat loss. You may have to reverse engineer things a bit, and work backwards from a heating water temperature of 115F which will get a floor temp of "x", with a corresponding heat output of "y". Then go back and reduce the heat losses of the house (if it's new). If this is a retro-fit, you may be challenged by the maximum heating water temperature from the geo heat pump. In that case the standard approach is to use a supplementary boiler to boost the HWS temp during peak heating season to get the higher HWS temperature required as the outdoor temperature drops. The geo heat pump would carry you over the majority of the heating season at the lower HWS temperatures.

David Van Wickler_4

Invest in half the system?????

You're making a large investment in geo. And then installing 1/2 a radint system?

Use plates, drop the required supply water temperature a minimum 20F and you'll realize your payback in COP. Have Uponor or your local rep calculate the required water temperature for both staple-up and plates, and take those supply temperature and calculate the heatpump efficiency. The difference divided into the cost difference of the plates versus staple up is your simple payback.

Rich L.

Plates

I think David is right on. If you must go under floor, at the temps available with geo you'll want to do plates. I did a job just like this, without hi-velocity, 3 hydronic air handlers instead and used extruded plates and it works great. It has an electric boiler to help boost temps in the coldest weather (-5* design). The electric boiler runs probably less than 5% of the heating season but the design of the house required slightly higher temps than the geo provided at design temp but the home owner insisted on the geo anyway. His electric utility provides electricity at half price for heating. Such a deal!

Do a accurate heat loss, go with the manufacturers specs for the plates and you'll be in business. One other note, if you go high velocity go over the minimum required outlets per tons of cooling to avoid a noisey system. These systems work good with water to water geo but if you shoot for the minimums, it will be noisey. Don't ask me (or especially my wife!) how I know!!!

Good luck! Rich L

singh

Not in our area.

I have not installed any staple/suspended tube systems here that did not need some supplemental heat, or 140-150*.
I would take the advice given here and start with the heat load first. Then insulate above the norm.
Perhaps then. But you'll have better luck with extruded plates, better yet, look into Warmboard.
I would also look into Econar GSHP. They better suited for cold climates than other heat pumps, IMO. And N&S Supply has them locally, plus they brought in the manufacturer to certify us. Econar may help with loop and equipment design also.
They also have a DualTek combo unit, water to water for the radiant, and water to air for heat and cooling, saving you the need for the Hi-V system.

Good Luck


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Weezbo

alter Natives?

let me drop this new gizmos name one time RAZORS. ok i feel better now.

for decades i have really wanted to give Solar and GSHP a try here in Alaska however it is not an inexpensive proposition...

with a heat loss in hand you could crunch numbers...you would likely have plates, extremely fine attention to insulation details, ventilation ,a philosophical awakening and revision of floor types and coverings...to maintain a base temp throughout the year....the next thing is how do you supplement that temp? maybe it requires some Myson ,Dianorm, buderus type radiant panels ...to make up the difference in the base temp to room temp at design.

convective baseboard can also release the potential of heat with convective currents .i am not making this up it is doable...the thing is in the number crunching period, you will have to keep the eraser around real close...staple up is not my favorite...lowest water temp is ...staying focused on the pencil and paper part of the work will be your best investment.

jimbo_7

Water to water GSHP radiant heat

Thanks for the reply. I only envision the hydro coils coming on after the floor loops have been off for a while in a deeper set back; the hydro coils aren't heated by a separate source, just used here because the dispersal method is quicker at bringing a zone to temp, if not as effective or economical as keeping one at temp, like the radiant. It would switch over to strictly loop circulation once temps approached 1 - 2* of set point. In other words, if there were 3 radiant loops (zones), split between 3 floors (basement, first and second), then the 2 hi-velocity fan coils (which were ducted to cover a respective floor) would comprise the 4th and 5th loops (zones) and only energize if set points were 4-5* above ambient conditions, in that respective zone. Make sense?

Rich L.

Hi velocity

In my system Modman, I use my Hi-Velocity in the shoulder seasons to take the chill off the house and avoid the fly wheel effect of my radiant floor. I control it strictly off of outdoor temps. I'm sure it could be used as a second stage as you suggest for quicker air temp recovery.

David Van Wickler_4

subject of radiant products

Warm board is great sure, but you're increasing floor height and no matter what there is a lot of fill in. Plus, I can always access my system through the sheetrock.

Be aware of supply temperatures with constant speed fans like Hi-Vel.

For low supply temps I would have looked at VFD air handlers.

David Van Wickler_4

YES

Spend 2 weeks now and enjoy the best decision for 20 years. It's a no brainer. Weigh the cost now verus the cost later.

Remember 100+ a barrel can effect electricty costs as well.

Rich L.

Energy costs

You bring up a great point David. Take a look at natural gas, propane and oil prices over the last decade. Basicly a steady rise until the last few years and then right through the roof! Electric rates haven't changed in years in my area. I'm not naive enough to think they won't, however I am enjoying that stability that my geo system is providing for now.

David Van Wickler_4

stable electric rates

Yes, when powered by water. My brother lives in West Virginia and his KW/hr is cheaper than any other fuel.

Rich L.

My Geo

Hi Modman, I'm running a Hydron Module w-w gshp, open loop system. Hydron Module is made in North Dakota and claim they design their equipment to operate in harsher climates. (such as North Dakota!) I can attest here in Iowa it's doing great. I have all radiant floor heat with my tubes in gypcrete. My system runs on outdoor reset and stats, 8 zones. When I got up this morning it was 10* outside, my water temp was reading 103*, and I had warm, very comfortable floors everywhere! I have lots of tile. Man I love this stuff. Unfortunatly my employer doesn't want to go after this market. I've had thoughts of opening my own shop to specialize in radiant, hydronics and steam heating, How do you know when the time is right to do that? Nevermind, I'll save that for another thread!!!

Like I said in an earlier post, I have done under floor WITH PLATES on a geo system, but be sure to do your heat loss calcs so you know you can meet the building needs for heat.

I personaly think the GSHP market is going to grow exponentially in the coming years and we as contractors can choose to embrace it or stand back and watch it pass us by. Sure it costs more, but so do high quality mod-con boilers and people are selling those all the time. Poeple will pay more up front for quality and to save money over time. How many people out there are driving Yugo's? How many of you when it was time for a new work truck went to the dealer and said "I want to buy the cheapest truck you have on the lot"? Exactly, we all want something nice, especially if we see the quality and value in it and the benefit it will provide us and our families.

Whoo, sorry, I may have gotten a little carried away there. I'll get off my soap box now! Rich L