Weatherite - Advantages of Direct Fresh Air Free Cooling of Data Centres

Advantages of Direct Fresh Air Free Cooling of Data Centres - Applications - Principles - Schematic

Free Cooling : Advantages

• Operating only the main supply fans for a large percentage of the time saves energy and money whilst reducing the systems carbon footprint.
• Free cooling freshens the room for occupants providing higher comfort levels.
• Pressurisation of Data Centre is improved, ensuring effective cooling distribution to server racks.
• Direct Free Cooling reduces wear and tear on expensive compressors and their accessories.
• With non-operation of mechanical cooling plant, free cooling reduces overall noise levels.

Free Cooling : Costs

• The resultant mechanical operating cost of free cooling is that of the supply fan, a damper and it’s actuator.
• Regular filter changes.

Cooling Unit Operation

The unit starts in fresh air mode delivering direct fresh air via the louvre and ductwork through the EC supply fan into the floor void. The air is discharged in to the room from the floor void via the floor grilles into the room or cold aisle containment, if installed.

The warm air from the Servers rises to high level and, due to the pressurisation in the room, flows to the Pressure Relief Ventilators (PRVs), where it is discharge to outside.

If PRVs are not deployed the condenser fan will operate, drawing the warm air back to the cooling units and discharging warm air to outside via ductwork and louvre.

If the outside air is too cold the unit will mix warm room air with the outside air to provide supply air at the required temperature to cool the Servers. As the outside temperature rises this mixing reduces to the point the unit is only supplying outside air.

As the outside temperature rises further and the room conditions cannot be maintained by direct fresh air, the damper will change position to divert the outside air to the condenser coil via the condenser fan. The refrigerant systems will start. The warm air from the Servers will return to the unit via the supply fan where it is drawn across the evaporator coil, cooled and then discharged back into the floor void.

Schematic Diagram

Typical Weatherite Outside Air Free Cooling DX Unit

The unit constantly reviews the internal and external temperature to determine if it can operate on direct fresh air cooling.