What Is a Free-Cooling Chiller?

A free-cooling chiller uses cold ambient air as a cooling source for process fluids. It reduces the amount of compressor-based refrigeration required when outdoor conditions are suitable.

The term does not mean that the system uses no electricity. Fans, pumps and controls still operate, so free cooling is more accurately understood as low-cost cooling.

Main Components of a Free-Cooling Chiller

• Free-Cooling Coil
  The free-cooling coil uses cold outdoor air to remove heat directly from the returning process fluid. When ambient conditions are favorable, the fluid passes through this section before reaching the mechanical refrigeration circuit.
• Mechanical Refrigeration System
  When ambient air alone cannot provide the required cooling capacity, the refrigeration system supplies the remaining cooling load. The mechanical cooling circuit works together with the free-cooling section to maintain the required process-fluid temperature.
• Evaporator
  The evaporator provides additional cooling when mechanical refrigeration is required. During conventional or partial free-cooling operation, it removes the heat that cannot be handled by the free-cooling coil alone.
• Fans and Airflow Section
  Cooling fans move outdoor air across the heat-transfer surfaces. They support both heat rejection during mechanical refrigeration and heat exchange through the free-cooling coil when ambient conditions permit.
• Fluid Circulation and Controls
  The circulation system moves process fluid through the chiller and connected equipment. Integrated controls manage the operation of the free-cooling and mechanical refrigeration sections according to outdoor conditions and the required process-fluid temperature.

Applications with Year-Round Cooling Demand

Free cooling is most useful for applications with a year-round cooling load and sufficient periods of low outdoor temperature.

• Industrial process-fluid cooling
• Data centers
• Mission-critical facilities
• Grow facilities
• Power generation
• Plastic manufacturing with constant process loads