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Cooling

Free Cooling

Using outside ambient air or water temperature to cool a facility without mechanical refrigeration, reducing energy use.

Full Definition

Free cooling (economisation) uses cool ambient outdoor air or water to remove heat from a data centre without running mechanical refrigeration compressors. An air-side economiser draws in filtered outdoor air directly when ambient temperature is low enough; a water-side economiser uses a cooling tower or dry cooler to produce chilled water. Facilities in cooler climates (UK, Nordic countries) can run in free cooling mode for thousands of hours per year, dramatically reducing cooling energy and improving PUE. ASHRAE A2+ allows supply air temperatures up to 35 °C, expanding free cooling hours.

Also Known As

economisationeconomizerair side economiserwater side economiser

Source Reference

ASHRAE TC9.9 — Thermal Guidelines for Data Processing Environments (2021)

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