Direct Free Cooling
With Direct Free Cooling, filtered outside air is used to keep the data center cool. This brings huge potential savings of up to 90%. If the outside temperature rises above the supply air set point, either an integrated DX system with compressors or a separate chiller assumes the task of cooling the data center.
Indirect Free Cooling
Direct Free Cooling brings challenges as well. With this cooling method, a large volume of outside air enters the rooms, so that extended temperature and humidity tolerances must be permitted. With Indirect Free Cooling, a system with a water/glycol mixture is used to cool the data center. Unlike with Direct Free Cooling, no outside air enters the data center with this cooling method. Air-conditioning systems with Indirect Free Cooling can be configured flexibly to suit requirements and are extremely efficient.
Indirect Dynamic Free Cooling
To further improve the efficiency of Indirect Free Cooling, STULZ has developed a dynamic control system for use with its own units. This system controls the mode in accordance with the current heat load in the data center and so considerably increases the number of operating hours in Free Cooling mode compared with other Indirect Free Cooling systems. Moreover, STULZ Indirect Dynamic Free Cooling has another operating mode – Extended Free Cooling – which further lengthens the time of Free Cooling mode and drastically reduces operating costs. The dynamic control cuts energy-intensive compressor cooling to a minimum.
