Air-cooled chillers for outdoor installation
With Free-Cooling function
Whenever cooling is required, even at low outdoor temperatures, year-round chillers with free-cooling capability are the right choice.
In relation to standard chillers, the Free Cooling units are equipped with an additional air-cooled heat exchanger. If the ambient temperature drops below the water inlet temperature into the unit, the free cooling function will be activated.
Water from the plant flows through the additional heat exchanger by switching over the internal number of water circuits. The water is coolved via the outdoor air, which reduces the compressor runtimes. If the ambient temperatures is low enough (round about 2 °C) the compressors are not used at all any more.
The whole cooling capacity can be achieved by the free cooling heat exchanger. The entire electrical power consumption of the compressors can be saved. Only the fans are in operation to cool down the water. The free cooling function allows you to ensure excellent energy efficiency throughout the whole year.
Method of operation of an air-cooled chiller with free cooling function:
Summer operation:
In summer operation the unit functions as a traditional air-cooled chiller. The free cooling function is not active.
Transitional mode:
As soon as the outside air temperature falls slightly below the water inlet temperature of the unit, the unit's internal water circuits are switched over and the additional free-cooling heat exchanger becomes active.
The missing cooling capacity is provided by the part-load mode of the compressor.
Already during transition seasons significant energy savings can be achieved by working in parallel mode.
Winter operation:
At sufficiently low outdoor temperatures, the entire compressor mode is not necessary.
All the required cooling capacity can be provided via the free-cooling heat exchanger.
If the outdoor temperatures continue to drop, the air flow rate is reduced in order to ensure constant medium outlet temperatures and to further lower the energy consumption.