Summer Cooling

Look HERE

Circular logic. The second entry is this CR4 thread.

Going to the Wikipedia entry we see the following:

http://en.wikipedia.org/wiki/Underfloor_heating

"With underfloor cooling, condensation may collect on the surface of the floor. To prevent this, air humidity is kept low, below 50%, and floor temperatures are maintained above the dew point, 19 °C (66F).^{[54] "}

So we can see that cooling with hydronic systems results in a delta T of about 14 F between the 66 F floor and the 80 F room.

Attempting to remove heat through the floor will not work as well as efforts to add heat through the floor..

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A warm floor can induce convection in a cool room. A cold floor in a warm room, does not induce convection.

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If the floor temperature is far enough below the room air temperature and you are in a humid area, there may be problems with condensation.

if you try that you're going to have a "sweaty" floor

GA. My first thought was moisture in places you don't want it. Just think of the mold possibilities. Now, if you were living in a very dry climate, perhaps not so bad. In a multistory dwelling, the upstairs floor would help keep the lower rooms a tad cooler, but I don't know how you would effectively cool the upper floors.

Also the heat transfer needs to be looked at. For hydronic heating, let's say you heat the water to about 120 F and the room is at 70 F, that's a delta T of 50 F. Comparatively, if you were cooling a room to 80 F, the same delta T would suggest you need water at 30 F to achieve similar heat transfer, convection issues not withstanding.

Cheers !!

While you are free to experiment, and recapitulate all the previous experiments, the ground to air heat / airconditioning sytems freely available solves the problem handily.

Visit the Yellow Pages for a local installer.

Tekmar 557 thermostat lists radiant floor cooling system:

http://www.tekmarcontrols.com/images/_literature/557_ul_01.pdf

http://www.taco-hvac.com/uploads/FileLibrary/Radiant_Floor_Cooling_Systems_-_ASHRAE_-_2008-9.pdf

Friends,

The first is a thermostat that includes the control logic for hydronic cooling--appropriate because the manufacturer is Watts Water Technologies.

The second is an ASHRAE technical paper--good reading. Yes, it is done successfully. However, the paper describes limits to the application, including minimum floor temperatures for personal comfort, the supplemental use of air cooling to remove latent heat (==humidity), and the advantages of this method for places where a significant portion of the heat load is radiant on a floor. This last, radiant heat load on a floor, is a direct contradiction of good solar design principles which have the solar heat load minimized in the summer.

All-in-all, it appears to me that this is a technology with a "track record". However, I believe that other ways to condition the space may be more cost effective in the vast majority of the cases.

--JMM

Yes. London Underground is considering/using the arrangement to cool tube stations during the summer.

Cold air tends to stay at floor level.Look at the open top freezer section in a supermarket.No lid required, because colder air is denser than warm air.The cold air ar floor level will require a lot of turbulent air flow to make it effective at at an effective level in the rooms.

Cold feet,hot head otherwise.

This is in addition to the caveats about moisture.

the idea with cooling is to "move heat" to a place you don't care about...move enough heat and you're left with "cool."so yes you could use ground water but not in a floor system. you'd have to pump the water to a chiller coil and use a fan to circulate warm air over the coil to pick up heat from the air...then return the now warmer water back to it's source. after you cost out all the coils, piping, solenoids, electrical pumping costs,etc. I think you'll find a conventional AC system makes far more sense., nice project, stay with the super insulation and a quality AC system and you'll be cool and happy