Free Cooling in Air Chillers                                    

Free Cooling is the ability of air compression chillers in industrial coolers or air conditioners to operate without the need for the compressed refrigeration cycle function of the existing chiller. In cold seasons of the year, the water circulating in the system can be cooled by separate air condensers that are installed outside the compressed chiller refrigeration cycle circuit in air chillers, and the cold air outside of buildings.

Free cooling is commonly used in industrial air conditioning systems.


Whenever the temperature of open spaces is lower than the building’s interior, this system functions as free cooling by using the cold air outside (without using a chiller refrigeration circuit compressor). In this state, this system replaces the chiller refrigeration circuit of air conditioning systems and therefore, the same result in temperature reduction can be achieved.


This technology is used in air conditioning (HVAC), in the interior of large commercial buildings (that, at the same time as heating in some spaces, may need cooling in others), or in industrial systems (for cooling perpetually-working devices) during the cold months of the year.

Free cooling generates cold water without using refrigeration and compressor-chiller cooling circuits, and can generally be used in late autumn, winter or early spring in regions with a temperate climate. Since the chiller is working in free cooling mode, the electricity cost is not completely eliminated, but free cooling reduces the load on the compressor and effectively reduces the air conditioning system’s electricity consumption and cost. Reducing the use of compressed air chiller refrigeration circuits brings about important savings in energy and cost.

In these conditions, the amount of electricity consumed by the chiller is limited to the function of the blower and fans, and removing the compressor reduces the electricity consumption considerably.


Free cooling is commonly used in air cooled chillers and its function, in chillers equipped with the free cooling system, is to separately feed the water into the free cooler coils that are installed on the chiller’s main condenser and cool the intended target by exchanging heat through absorbing the cold air of the environment and the building’s exterior (for cooling devices in industrial processes, and cooling the water of air handing unit coils or coil fans).



Free cooling is not commonly used in cold water chillers, since there is a possibility for the cooling tower water (the temperature of which has fallen due to the cold air outside) to be fed directly to the chillers’ water consuming coils. Also, if the cooling tower is an open tower, a strainer is required for physical treatment of the tower’s output water.