Geo-Thermal & Radiant

DaveC

Anyone doing this much?
I have been wanting to, and now have have a job coming up that may go that way. Any help?
Thanks Bill

Fred Harwood

Geothermal

What kind? Hot springs or just lots of pipe in the ground?

GMcD

Yes

We are currently designing, and have been involved in past projects locally that use geothermal water source heat pumps for radiant heating and cooling systems, both in residential buildings and other types of buildings. The Pacific NW climate where I am, while a heating dominated climate, still has some applications if the building energy balance is done right, and some economical geo-exchange method is employed (horizontal slinky coils, absorber piles, etc.) Geothermal heat pumps are a great match to radiant heating and cooling systems since properly designed radiant systems only need low temperature heating water and moderate temperature cooling water.

DaveC

Type

I'm looking at using water to water heat pumps, with ground loop exchange. Looking at Florida Heat Pump brand.

Ball Valve

Heat pumps are great. If you go with a FHP check it over carefully when you get it. Have seen new with broken piping from the factory. Larger units(over 2 ton) seem to be constructed better than the smaller(1 and 1.5 ton)units. Dont know why but suspect it has something to do with the speed and amount of the little units that are produced. I would also stay away from a rotary type compressor and get a scroll or recip. I service a college dorm with 200+ of these babies. Dorms are the small 1.5 ton and the halls and makeup air units are larger units 2-5 tons depending on the purpose. Hope this helps. This is all from first hand experience.

Paul Rohrs_2

Buffer Tanks are a must......

Do yourself a huge favor and add a buffer tank. I have seen some units not "extract" heat fast enought and trip the geo unit out on a "high pressure" switch.

Attached is a photo of the mech and elect of the job we did.
Slab on grade radiant, two zones with Tekmar 501's to control some ultra high mass slabs.

We used a Tekmar 150 for the buffer tank aquastat so that we could adjust the differential and setpoint temp. It is working great.

Regards,

PR

jw

7 ton job

Did a FHP "pump 'n dump" system with great success. Set it up with a "reverse" indirect tank for a buffer and used the potable side of tank to preheat the domestic before the electric water heater. Techmar 367 zone control on radiant side.

Interesting side note with the techmar. The control went nutz with blinking lights that were not normal when first fired up. Could get no ac or dc voltage on stat wires when disconnected from control, but could get a "buzz" off of 'em when I touched them. Turned out that we were close enough to an am radio station to get an RF signal that confused the heck out of the control. Fixed it by grounding one side of the stat wires from the RTU's. Live and learn, eh?

John

Floyd_5

Check this guy out....

http://www.ourcoolhouse.com/
He did what your thinking and has all the data right here for you to see.... even go into detail about what he did and had a forum for you to ask ????'s

Floyd

DaveC

Thanks

Thanks for the info guys. Everyone should check out Malone's home page http://www.ourcoolhouse.com/

Jimmy Gillies

Geo Thermal

Geoff.
We have been asked to get involved in a couple of Geo Thermal heat pump project here on the West Coast of Scotland. They are for small houses.
Can you give me any links to good web sites. I will try www.ourcoolhouse.com.
Thanks for your help.
Jimmy Gillies. Scotland.

Mark Eatherton1

We use Water Furnace...

and have found them to be a good responsible company with a great product line.

ME

Jimmy Gillies

Thanks

Thanks Mark.
I'm talking to their Rep here in Scotland.
Regards.
Jimmy

hr

I have one, under my belt

it's on winter number 3. The owners are very happy. It is a Hydro Temp from Pocohontas, Arkansas. They custom built it to the radiant load for the basement slab, while the upstairs is FA.

And yes, the buffer tank is critical. I used a 50 gallon electric water heater by using the upper and lower element holes (1") for my connection for the heat pump. The radiant pulled from the lower drain opening and upper HW outlet. This assures a good blend within the tank.

Paul's drawing is a good one as long as the HP to buffer connections allow good mixing in the tank. His drawing, while conceptual, shows both in and out at the same point.

My only complaint was the noise. Luckily this was on a basement slab and they built and insulated around 'er. It's an incredibly noisy piece of equipment. Compared to a boiler. Lots of recriprocating going on inside that sheet metal box!

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mark Eatherton1

And here I thought...

that was a BEER belly, then I remembered, you don't drink:-)

I agree with what you said about noise. You can't provide enough vibration isolation on these puppies. Especially when they're on the upper framed floors of multi storey'd homes.

Sounds like the worlds BIGGEST refrigerator. HUMMMMMMMMMMMM

ME

Mark Eatherton1

Get ready..

for some MUD!! Probably one of the biggest over looked factors to doing GSHP is the consumers reaction to having well drilling rigs in their front yard. Their initial reaction is generally "OH MY GAWD!!! I didn't know that you were going to be doing THIS in my yard!" To which you reply, "Don't worry, your grass will grow back, eventually..."

Fortunatley for this customer, it was new construction and the landscaping hadn't been started yet.

Here's some dirty pictures.

BTW, the telephone cable had been abandoned, thank God...

Enjoy!

ME

Earthfire_2

loop field

We have also used horizontal loop fields and the occassional slinky. Personally prefer horizontal since we can handle 100% of the install ourselves.But on small development or town lots,where space & run off was a issue, we have had the driller bring in a vacumn unit like the utility drillers use , to suck up the excess water from the drill work.

Jimmy Gillies

Oil

Mark. How deep do you drill down & as our North Sea oil fields are running low have you ever struck OIL ! !
Regards.
Jimmy Gillies

Mark Eatherton1

Not THAT deep...

typically 200 to 300 feet deep depending upon soil structure. I have heard of drillers drilling through abandoned coal mines. Makes it pretty difficult to grout the pipes in after the fact.

The drill rig has a large air compressor on it. This is what they use to force the cuttings to the surface. During one of his bores on this site, the soil, about 50 feet from where he was drilling, started blowing up like a balloon. Pretty soon, the bubble cut loose and there was water and mud flying everywhere. The driller just smiled and yelled "Crowd control!!" Sure got my attention:-)

ME

Michael Dilling

geothermal water heating for domestic and radiant panels

I'll wade into the fray by saying we've been doing these things very successfully for over 20 years. I agree the buffer tank is a must as it makes up for the difference between the capacity of the geothermal equipment and the load placed on the system. These two never match and you end up with serious control and performance problems if a buffer is not used. The other issues that need attention are flow rates of water and pump and pipe sizing. In a geothermal system, a wide temperature rise is bad, small is good. I usually design for a 7 to 10 degree rise maximum. The reason is that I'm looking for the buffer to hold BTU's and the higher the return water temperature, the more BTU's in storage. The small temp rise allows me to put more BTU's in storage without raising operating pressures to the edge of optimum limits and extends equipment life. I've done these systems with open loop, closed loop and DX system designs, all with great success if attention is paid to design. Good luck with your project.