Blazer retractable convertible top

[hgs_notes]

The water used can be mixed with glycol to lower the freeze point, but that is usually just used when the water is heating a slab outside the building, like to melt the snow off the driveway or sidewalk. Once the slab in the garage is warmed up it would take several days below freezing before it would freeze, and with the pex tubing incased in cement, it shouldn't ever expand enough to damage the tubing, which is also flexible. I've seen large old buildings go without heat for a few days with temps below 0 F and be comfortable.

I'm a boiler inspector by trade and see these systems all the time, but I have never seen one run with cooled water through it. Maybe I misunderstood what you are planning. A cold slab will end up absorbing a lot of moisture and seem damp all the time. Could end up with mold problems. Can't say I would recommend it.