Put simply this type of system is more useful for large buildings comprising of a number of floors or area’s. It has the plant room where all the important equipment such as the evaporator is housed to chill the brine/water which is then pumped to the various air handling units installed at different floors or locations of the building.
The air handling units comprise the cooling coil through which the chilled brine/water flows, and the blower. The blower sucks hot return air from the room via ducts and blows it over the cooling coil. The cool air is then supplied to the space to be cooled through ductwork. The brine solution which has absorbed the room heat comes back to the evaporator, gets chilled and is again pumped back to the air handling unit.