The Different Technologies for Cooling Data Centers

Overview

The paper is a taxonomy describing the basic ways to collect heat from the IT space and move it outdoors. It covers air-cooled DX, glycol-cooled, water-cooled and chilled-water systems, pumped refrigerant, self-contained and rooftop units, direct fresh-air evaporative cooling and indirect air economizers. Each method is shown as a simple loop diagram with its main components and a list of pros and cons. In total 13 basic heat-removal methods are identified, 11 of which rely on the refrigeration cycle as the primary means of cooling. This allows the options to be compared quickly.

Pumped refrigerant systems isolate the primary heat-removal loop (chilled water) from the IT equipment, keeping water out of the white space. Direct and indirect air methods depend on outdoor conditions as the primary cooling source and suit mild climates. The paper also states what the choice should follow: uptime requirement, power density, location and climate, size of the IT space, available building systems, and time and budget. It offers a conceptual comparison rather than capacity calculations, so current equipment efficiencies should be verified separately.

The taxonomy is a natural base for a cooling-plant catalogue: each type can carry attributes such as heat-rejection medium, water need, economizer capability and typical scale. A wizard should filter these types by climate and IT load scale; for example, air-side economizers should be offered only in mild or cool climates.

Key points

1. 13 basic heat-removal methods are identified; 11 rely on the refrigeration cycle as the primary means
2. Pumped refrigerant systems isolate the chilled-water loop from the IT equipment, keeping water out of the white space
3. Direct and indirect air methods depend on outdoor conditions and suit mild climates
4. Selection drivers: uptime, power density, location/climate, IT space size, building systems, time and budget
5. Systems covered: DX, glycol, water-cooled, chilled water, pumped refrigerant, self-contained, rooftop, direct fresh air, indirect economizer

Using it in design

• Use the 13 methods to seed the cooling-plant catalogue enum (dx_air, dx_glycol, dx_water, chw_crah, pumped_refrigerant, self_contained, rooftop, direct_fresh_air_evap, indirect_air_economizer)
• Give each type heat-rejection medium, water need, economizer capability and typical scale attributes
• In the wizard, filter types by climate (air-side economizers only for mild or cool climates)
• Also filter types by IT load scale

Who should read it

Designers selecting a cooling system type and engineers new to data-centre cooling.

Related standards

• ASHRAE TC9.9 Thermal Guidelines
• ASHRAE 90.4

Publication details

Authors

Tony Evans

Publisher

Schneider Electric

Year

2012

Document number

WP 59

Document language

English

Source type

Manufacturer

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation