Data Center Design Considerations (HVAC)

A data center design encompasses architectural (rack layout), structural, mechanical, electrical, fire protection, and cabling system. Sustainable design is essential because a data center can consume 40–100 times more electricity compared to a similar‐size office space.

Data Center HVAC

Design Guidelines

Since a data center involves 82–85% of initial capital investment in mechanical and electrical equipment, data center project is generally considered as an engineer‐led project. Areas to consider for sustainable design include site selection, architectural/engineering design, energy efficiency best practices, redundancy, phased deployment, etc. There are many best practices covering site selection and building design in the Leadership in Energy and Environmental Design (LEED) program. The LEED program is a voluntary certification program that was developed by the U.S. Green Building Council (USGBC).

Early on in the architecture design process, properly designed column spacing and floor elevation will ensure appropriate capital investments and minimize operating expenses. A floor plan with appropriate column spacing maximizes ICT rack installations and achieves power density with efficient cooling distribution. A floor‐to‐floor elevation must be carefully planned to include height and space for mechanical, electrical, structural, lighting, fire protection, and cabling system.

International technical societies have developed many useful design guidelines that are addressed in detail in other chapters of this handbook:

  • ASHRAE TC9.9: Data Center Networking Equipment
  • ASHRAE TC9.9: Data Center Power Equipment Thermal Guidelines and Best Practice
  • ASHRAE 90.1: Energy Standard for Buildings
  • ASHRAE: Gaseous and Particulate Contamination Guidelines for Data Centers
  • Best Practices Guide for Energy‐Efficient Data Center Design
  • EU Code of Conduct on Data Centre Energy Efficiency
  • BICSI 002: Data Center Design and Implementation Best Practices
  • FEMA P‐414: “Installing Seismic Restraints for Duct and Pipe”
  • FEMA 413: “Installing Seismic Restraints for Electrical Equipment”
  • FEMA, SCE, VISCMA, “Installing Seismic Restraints for Mechanical Equipment”
  • GB 50174: Code for Design of Data Centers
  • ISO 50001: Energy Management Specification and Certification
  • LEED Rating Systems
  • Outline of Data Center Facility Standard by Japan Data Center Council (JDCC)
  • TIA‐942: Telecommunications Infrastructure Standard for Data Centers

Chinese standard GB 50174 “Code for Design of Data Centers” provides a holistic approach of designing data centers that cover site selection and equipment layout, environmental requirements, building and structure, air conditioning (mechanical system), electrical system, electromagnetic shielding, network and cabling system, intelligent system, water supply and drainage, and fire protection and safety.

Reliability and Redundancy

“Redundancy” ensures higher reliability, but it has profound impacts on initial investments and ongoing operating costs:

Cause and effect diagram

Computational Fluid Dynamics

Whereas data centers could be designed by applying best practices, the locations of systems (rack, CRAC, etc.) might not be in its optimal arrangement collectively. Computational fluid dynamics (CFD) technology has been used in semiconductor’s cleanroom projects for decades to ensure uniform airflow inside a cleanroom. During the initial building and rack layout design stage, CFD offers a scientific analysis and solution to visualize airflow patterns and hot spots and validate cooling capacity, rack layout, and location of cooling units. One can visualize airflow in hot and cold aisles for optimizing room design. During the operating stage, CFD could be used to emulate and manage airflow to ensure the air path does not recirculate, bypass, or create negative pressure flow.

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Best Practices

Although designing energy‐efficient data center is still evolving, many best practices could be applied whether you are designing a small server room or a large data center. One of the best practices is to build or use ENERGY STAR servers and solid‐state drives.

The European Commission published a comprehensive “Best Practices for the EU Code of Conduct on Data Centres.” The U.S. Department of Energy’s Federal Energy Management Program published “Best Practices Guide for Energy‐Efficient Data Center Design.” Both, and many other publications, could be referred to when preparing a data center design specification.

Here is a short list of best practices and emerging technologies:

  • In‐rack‐level liquid cooling and liquid immersion cooling
  • Increase server inlet temperature and humidity adjustments (ASHRAE Spec)
  • Hot and cold aisle configuration and containment
  • Air management (to stop bypass, hot and cold air mixing, and recirculation)
  • Free cooling using air‐side economizer or water‐side economizer
  • High efficient UPS
  • Variable speed drives
  • Rack‐level direct liquid cooling
  • Fuel cell technology
  • Combined heat and power (CHP) in data centers
  • Direct current power distribution
  • AI and data analytics applications in operations control.

It is worthwhile to note that servers can operate outside the humidity and temperature ranges recommended by ASHRAE.