A customer of mine from my old health food store invented a process he received on for "radiant" cooling. Of course cooling isn't radiant it is the opposite, but the concept is using the city water supply in a bldg somehow routed to pump through some way in the floors and walls. When it is hot, simply turn on the water through those areas and it should be about 55F (ground temp) of the city water and the warmth in the room or area will be drawn towards the cool water moving through walls and floors. Also, the water isn't really being used up. Or, it can be turned on an whenever water is used, that water will circulate accordingly pulling some heat away with it. Brilliant and simple and something so easy can be done now.

Just learned about city water supply temperature used also for heating and cooling in large industrial size. Will post links about it if I can get it. 100,000 square foot bldg costs about $100/month to heat or cool by this method.