What is a Chiller ?

A "chiller," for our purpose, is a refrigeration system that cools water.  Air conditioners and dehumidifiers condition the air while a chiller, using the same refrigerating operations, cools water, oil, or some other fluid.  This chilled solution can be used to cool a wide range of operations. To see a chiller system layout and the step by step path of the cooling cycle

 Chiller refrigeration cycle

Description of a basic chiller refrigeration system: 
Starting at the compressor; the refrigerant is compressed and sent out of the compressor as a high temperature, high pressure, superheated gas. The refrigerant travels to the condenser  (Which can be air cooled by fans or water cooled by tower or city water). 

The condenser changes the refrigerant from a high temperature gas to a warm temperature liquid. It then travels into a receiver (optional component). It continues to the Thermal Expansion valve or TXV. The TXV meters the proper amount of refrigerant into the evaporator. 

The TXV takes the high pressure liquid and changes it to a low pressure cold saturated gas. This saturated gas enters the evaporator  where it is changed to a cool dry gas (no liquid present). The cool "dry" gas then re-enters the compressor to be pressurized again.....

The hot gas by pass (unloader assembly)  is used to stabilize the cooling output of the refrigeration system by allowing hot gas to warm up the cool evaporator. This causes a reduction in to cooling efficiency and a stabilizing of the chilled water temperatures. 

There are a few other unloader concepts that are used in the refrigeration systems, but ideally accomplish the same outcome. There are also other specialized components that you may find on "your" chillers' refrigeration lines; such as solenoid valves, a liquid site glass, accumulators or subcoolers.

A few of the most common process chiller application examples:

1. The Plastics Industry -  Cooling the hot plastic that is injected, blown, extruded or stamped.  (There are other  types.)

2. The Printing Industry - Cooling warm rollers due to friction and ovens curing the ink, along with ultraviolet lamps also for curing purposes.

3.  The Medical Industry - MRI systems - The hospital MRI units need to be cooled to operate properly.

4.  The HVAC industry - Large scale air-conditioning systems pump this chilled water to coils in specific areas of, lets say, a high rise building. The air handling systems for each area open and close the water flow through it specific area keeping the air of the rooms at a desired temperature.

5.  The Laser Cutting Industry -  Technology has created machines that can cut out very specific steel products with the precise use of a laser cutting machine.  These lasers run at very high temperatures and must be cooled to run properly.

~Terence Choong~