Free cooling
Free cooling is an economic method of using low external air temperatures to assist in chilling water, which can then be used for industrial process, or air conditioning systems in green data centers.
When the ambient air temperature drops to a set temperature, a modulating valve allows all or part of the chilled water to by-pass an existing chiller and run through the Free Cooling system, which uses less power and uses the lower ambient air temperature to cool the water in the system.