Two comments on the hydronic heat-- -It is more efficient (at least in theory) to have the pipes off the insulation because the concrete is going to be at a lower temperature than the pipes, so you have less heat loss. In practical terms though, you get to a steady state with the ground over time so I doubt it is a huge impact. -You can hydronically cool a concrete floor; it is done in the airport in Bangkok. For a home, you would just need to ensure that you never let the water temperature go below your dewpoint temperature. As you mention, you do need dehumidification still, and if you want to cool below the outside dewpoint then you need air conditioning. (The Bangkok airport uses very low temperature outside air cicrculation for dehumidification.) Cooling from the slab in a tall space has the advantage of creating a cool zone at the floor and allowing the heat to rise. Obviously though in a 2-story space you are going to need traditional cooling for upstairs and that displacement property will go away. Using a heat pump water heater is another option if you are all-electric, which in most places will net out about equal to a propane system.
Hydronic cooled slabs are a thing and they work... but generally only in places with low humidity unless you have a very tight building with good dehumidification. Radiant heat doesn't rise... warm air does. So it doesn't really matter that the slab is the cold part. However, cold ceilings are better than floors for a few reasons. They are closes to the hottest part of our bodies (our heads), they are less impacted by furnishings, and no one really wants to walk around barefoot on a cold floor, even in the summer. Also, with cooling, its better NOT to use a massive surface like a concrete slab because it cannot react fast enough to changes in humidity (say an open window), or when the sun goes down or clouds pass... a cool mass will continue to suck heat out of you (like being in a cave). I wouldn't recommend a DIY builder do much with radiant cooling... however you can still do hydronic cooling so you can use the same ground source heat pump to heat and cool your home. Instead of cooling the slab, you would add a few loops for hydronic cassettes like: th-cam.com/video/jcjTkU1tOfE/w-d-xo.html. There are some cool products in development for cool ceilings: th-cam.com/video/rPC0_LxlwIY/w-d-xo.html or more recently th-cam.com/video/fZUvuJpsq9U/w-d-xo.html
Can’t wait to hear about flooring options; concrete polishing vs. carpet/wood etc
Two comments on the hydronic heat--
-It is more efficient (at least in theory) to have the pipes off the insulation because the concrete is going to be at a lower temperature than the pipes, so you have less heat loss. In practical terms though, you get to a steady state with the ground over time so I doubt it is a huge impact.
-You can hydronically cool a concrete floor; it is done in the airport in Bangkok. For a home, you would just need to ensure that you never let the water temperature go below your dewpoint temperature. As you mention, you do need dehumidification still, and if you want to cool below the outside dewpoint then you need air conditioning. (The Bangkok airport uses very low temperature outside air cicrculation for dehumidification.) Cooling from the slab in a tall space has the advantage of creating a cool zone at the floor and allowing the heat to rise. Obviously though in a 2-story space you are going to need traditional cooling for upstairs and that displacement property will go away.
Using a heat pump water heater is another option if you are all-electric, which in most places will net out about equal to a propane system.
I’m still curious how to frost protect the columns. Don’t the inside radius of the concrete pillars reach the inside of the home or is it below grade?
Hydronic cooled slabs are a thing and they work... but generally only in places with low humidity unless you have a very tight building with good dehumidification.
Radiant heat doesn't rise... warm air does. So it doesn't really matter that the slab is the cold part.
However, cold ceilings are better than floors for a few reasons. They are closes to the hottest part of our bodies (our heads), they are less impacted by furnishings, and no one really wants to walk around barefoot on a cold floor, even in the summer. Also, with cooling, its better NOT to use a massive surface like a concrete slab because it cannot react fast enough to changes in humidity (say an open window), or when the sun goes down or clouds pass... a cool mass will continue to suck heat out of you (like being in a cave).
I wouldn't recommend a DIY builder do much with radiant cooling... however you can still do hydronic cooling so you can use the same ground source heat pump to heat and cool your home. Instead of cooling the slab, you would add a few loops for hydronic cassettes like: th-cam.com/video/jcjTkU1tOfE/w-d-xo.html.
There are some cool products in development for cool ceilings: th-cam.com/video/rPC0_LxlwIY/w-d-xo.html or more recently th-cam.com/video/fZUvuJpsq9U/w-d-xo.html
Do you use wire or fiber in the concrete?
Do you sale this insulation board?
Look into geothermal to cool the slab. It’s happpening
Water furnace synergy system
In floor radiant cooling already exists. Daikin Altherma
I thought the plastic was supposed to go on top of the foam...
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