Free Cooling Chillers
If a building requires a Cooling system which operate continuously throughout the year, it is energetically convenient to use Chillers which have been designed to exploit these conditions; Chillers with free-cooling are a typical solution. Not only do these units have a lower energy consumption than traditional systems, they also limit the quantity of indirect CO² emissions into the atmosphere. If the external temperatures are low enough, it is possible to reduce or even eliminate, the use of compressors.
For this reason, Flakt Woods Chillers are equipped with free-cooling devices allow operation even when the external temperature is able to guarantee only partial, rather than complete dissipation of the thermal load. In these cases, operation is referred to as mixed: the chiller uses external air to pre-cool the water in the system, allowing the compressors to work less and create energy savings.
There are, therefore, three operating modes:
Mechanical cooling
With temperatures higher than 15°C, the free-cooling unit operates as a traditional chiller, dissipating the thermal load of the evaporator with the compressors (fans and compressors operating);
Mixed cooling
When the external temperature is between 5 and 15°C, the air guarantees only partial, rather than complete, dissipation of the thermal load. At lower temperatures the control system activates the free-cooling pump at 15°C and the water is routed to the air/water exchangers which are placed in series in the evaporator, so that it has to dissipate a lower thermal load (fan operation, free-cooling pump and, in part, the compressors);
Free-cooling
When the external temperature is low enough, the air/water exchangers allow the complete dissipation of the thermal load without needing the compressors