Radiant cooling has actually been around for quite some time and works the same way as radiant heating, but in reverse.
In radiant heating, the thermal energy (heat) from the water within our radiant ceiling panels is transfered to the room. Whereas in radiant cooling, thermal energy is transferred from the warmth of the room to the cool water within the panels.
As the water heats up, it is pumped out of the panels and replaced with cold water again. This continues as needed to cool the space.
Radiant cooling is like walking into a cave on a warm day. The cave walls are colder than your body temperature. Therefore, you begin to radiate thermal energy to the walls of the cave and, as the cave absorbs your thermal energy, you begin to feel cool.