Free cooling
Standards
Free cooling consists of cooling a building by ventilation using the free energy of the external air or water when it is at a temperature below the required internal conditions. This system also reduces the need to use cooling units, which leads to a reduction in energy bills and improved eficiency of the whole installation (PUE and carbon footprint).
The class (A1 to A4) of a data centre, deined by the ASHRAE standard, is assigned according to the equipment in the data centre and its speciic environmental features.
Free cooling includes overall management solutions via the primary cooling circuit and targeted management solutions in the white room via the secondary cooling circuit. Air
Piping
Ambient air
Equipment (ASHRAE - 2011 Thermal Guidelines) 2011 classes
2008 classes
A1
1
A2
2
A3
NA
A4
NA
Applications
DATA CENTRES
IT Equipment
Environmental control
Enterprise servers, storage products
Tightly controlled
Volume servers, storage products, personal computers, workstations
Some control
Class A1: typically a data centre with tightly controlled environmental parameters (dew point, temperature and relative humidity) and mission critical operations. Classes A2/A3/A4: typically an information technology space or ofice or laboratory environment with some control of environmental parameters (dew point, temperature and relative humidity).
Secondary cooling circuit
Primary cooling circuit