All-Water Systems

All air-conditioning is achieved by water-air heat exchanger at terminal. Examples:

• Fan-coil

• Unit ventilator

• Radiant panels

All-Water Systems

Fan coil units do not provide ventilation.

Unit ventilators draw air in through walls (see schematic at right)

Outdoor air

This system may be only for heating: O

Fan coils have no OA, while unit ventilator has OA intake. Infiltration is a mechanism that provides fresh air in spaces with no OA.

Advantages: small/no plenum, individual control, and simple retrofit.

Disadvantages: high maintenance, condensate in occupied space, poor humidity control, and mediocre ventilation control.

120° MOIST AIR

Posted in Fundamentals of Heating. Ventilating, and Air-Conditioning