Chiller - fancoil system. From Wikipedia - the free encyclopedia

Chiller is a water-cooling machine which use vapor compression or absorption refrigeration cycle. Chilled water may be used with the fan-coil system or for equipment cooling.  During the cooling chiller generates excess heat that have to be abstracted in the environment.

Chiller - fancoil system is a centralized multi zone air-conditioning  system. This system use a liquid which circulates between chiller and heat exchangers (local fan-coils) with a relatively low pressure. As a liquid may be used water or water-glycol mix. Besides chiller and fan-coils this system consists of pump station and automatic control.

Terminology:

Translation for «chiller»  is missed in GOST 22270-76 «Equipment for air conditioning, ventilation and heating». For the «fan coil unit» - fan closer (the closer is worked with the built-in fan local recirculation and flow in the room is a mixture of indoor air with outdoor air which having passed pre-processing in the central air conditioner and also heating and/or cooling air)

Advantages:

Advantages in Advantages in comparison with split-systems.

• Scalability. Number of fan-coils is limited only by cooling capacity of chiller.
• The minimum volume and area. The air conditioning system of a large building may contain a single chiller, which occupies a minimum volume and area. Exterior of building staying the same.
• Practically  unlimited distance between chiller and fan coil units. Length of tracks may reach hundreds of meters. Heat losses per meter are much lower in comparison with a refrigerant gas system.
• The piping cost. For the piping uses standard water pipes and valves. Adjustment of water system much easier then  refrigerant gas system.
• Safety. Refrigerant gas uses only in chiller which usually placed outdoor. Water circuit has valves to prevent the accidents.

Disadvantages:

The system chiller-fan coil units are more effective  in electricity consumption than roof-mounted systems but less economy in comparison with systems with variable refrigerant flow (VRF). However maximum capacity VRF-system is limited.

Failures:

• Freon leak. Freon leakage may be caused by non-hermetic connections of the refrigerant circuit.
• Compressor breakdown. This may be caused by electrical reasons or mechanical damages of piston group.
• Moisture in the refrigeration circuit. Moisture in the refrigeration circuit may appears with damages in the evaporator.

Notes:

1. GOST 22270-76 (ST SEV 2145-80). USSR State standards.  76 «Equipment for air conditioning, ventilation and heating»pdf