Radiant cooling

[Tempted]

I Have a gshp with radiant infloor residentual project.

Looking for others with hands on experience, with radiant infloor cooling.

[Nuclrchiller]

Subscribing to this thread to watch and learn. How is dehumidification handled? Multiple options? Thanks. Also, what about effects of temperature variations on the flooring?

[SolarMike]

Cooling is tricky but doable. Some of the European companies (and maybe Tekmar) have controls that will measure RH, floor surface and air temps and mix the water temp to keep the surface just below air temp but not enough to cause condensation. As said above, you still have to de-humidify.

[motoguy128]

While I see the benefit of sharing the came set of loops. Cooling in not radiant. Cooling is best achieved through air movement since it's percieved by evaporation. Therefore air movement nd humidity levels have a greater effect than actual temeperature. Radaint heat is effective because we ca be effectively warmed with indirect infrared energy like a hot dog on rollers in a glass case.

It seems like it would be more efficient to use an air handler and get some air movement and moisture removal.

Besides, even in summer, who wants a cold floor. Heck, I could almost see using the radiant loop for dehumidification to heat the floors a little, which would increase sensible load for longer run times. Similar ot hot gas reheat, but putting heat in hte floor rather than tempering the air.

[SolarMike]

I've only been involved in a couple of radiant cooling jobs, one was a warehouse for grains and they had De-humidification by some desiccant wheels (I wasn't involved in that part). I put the tubing, sensors and other boiler equip in. I really don't know how well it worked but i do know they didn't want a lot of airflow.

[Tempted]

From what I have gleaned so far in researching it and without getting indepth with formulas.
The humidity control is the ongoing concern. So far the use of aqua a/h's to lower the RH is the method of choice in residentual apps. With testing they have found that use of a regular humidity control mounted at stat hieght works well as tests show no significant difference in humidity near the floor.
The combination of the the 2 systems, radiant and air has the lowest operating cost and better performance.
While most sites contain the same information, with a few relating to having experience installing. And the few with experience aren't giving out any relavant info.
I found 1 site that did testing and the results of the tests. It's from 2003 in Korea but good info with detail.

http://www.ibpsa.org/proceedings/BS2...3_0729_736.pdf

[SolarMike]

I use REHAU tubing almost exclusively for my floor heating so here is a link to their radiant cooling site.

http://www.rehau.com/cms/servlet/seg...diant_Cooling/

[Tempted]

Thanks Mike. I use Rehau also. They are going to help out on the tubing design.

[SkyHeating]

We have been quoting both Mitsubishi ductless units with ceiling cassettes(for the asthetics) or putting in a ducted system with something like a Synergy 3D WaterFurnace all in one unit with two stages of ducted heating/cooling and radiant infloor heating.

Your not to far away from me, we have two radiant geo projects going on right now that are adding cooling. One is ducted cooling, the other is 8 ductless wall ports.

[Tempted]

We have been quoting both Mitsubishi ductless units with ceiling cassettes(for the asthetics) or putting in a ducted system with something like a Synergy 3D WaterFurnace all in one unit with two stages of ducted heating/cooling and radiant infloor heating.

Your not to far away from me, we have two radiant geo projects going on right now that are adding cooling. One is ducted cooling, the other is 8 ductless wall ports.

Hi Travis, So your not actually doing radiant cooling, your just adding cooling to radiant infloor, right?

[SolarMike]

One thing I would look at is the tube spacing. Just as a 6" spacing will use a lower heating water temp than an 8" spacing, the 6" spacing will have a higher water temp needed for cooling.

Remember that the same rules about having a low enough output temp to reduce humidity don't apply in floor cooling. You may have to address it in another way for humidity removal but a lot of energy can be saved by keeping the tube spacing tight and keeping the water temp as high as possible for the conditions.

I know in Europe they are often using 4" spacing for heating with heat pumps just to get the approach temps as low as possible.

Also, inverter type heat pumps have a lot less value when you are using it to primarily heat/cool a slab vs a traditional air heating/cooling. There are no typical issues with cold air blowing during defrost for example.

[SkyHeating]

Hi Travis, So your not actually doing radiant cooling, your just adding cooling to radiant infloor, right?

Thats correct, I have not heard of a good way for Radiant Cooling that I would feel comfortable putting in a home. There is the condensation issue with slab cooling and its very hard to remove naturally rising heat out of the floor. There is also the issue of changing over your water storage from heating to cooling and I find that in our climate this could be very inefficient without two tanks and additional controls at which point it was cheaper and more effective to go with a ducted(off the geothermal) or ductless cooling solution.

If there is a way to do it I am certainly open to learning. But in a climate such as yours and mine that requires the possiblity of heating and night and cooling during the day it can potentially be very costly to switch back and forth daily.

[Nuclrchiller]

I would also be concerned about what happens to the flooring due to different rates of expansion between the subfloor and whatever is on top- hardwood, laminate, tile,... I think radiant infloor cooling would have to an extremely small niche. I expect to never see it myself- on the job or off.