Absorptive Sound Barrier Walls & Fan Silencers

Data centers require large amounts of cooling to maintain reliable operation of servers and other critical equipment. Large data center campuses may utilize dozens of air-cooled chillers and condensing units operating continuously throughout the year, commonly grouped together in outdoor mechanical yards known as chiller farms.

The condenser fans, compressors and mechanical components associated with this equipment can create significant environmental noise. When multiple chillers are grouped together in a data center chiller farm, the combined sound level can affect nearby residential communities and property lines.

eNoise Control provides engineered data center chiller farm noise control systems including absorptive sound barrier walls, acoustical fan silencers and predictive acoustical modeling.

Data Center Chiller Farm Noise Sources

Air-cooled chillers and condensing units typically contain multiple condenser fans located on top of the equipment. These fans pull large volumes of air across the condenser coils and discharge the air vertically.

Condenser fan noise can be a significant contributor to the overall sound level of a data center cooling system. However, the fans are not the only noise source.

A chiller farm may generate noise from:

• Condenser fans
• Fan air intake
• Compressors
• Refrigerant piping
• Pumps and motors
• Mechanical vibration
• Multiple pieces of equipment operating simultaneously

For this reason, treating only the condenser fan discharge may not provide the most cost-effective solution for a large data center chiller farm.

Absorptive Sound Barrier Walls for Chiller Farms

An effective method of controlling data center chiller noise is an absorptive sound barrier wall installed around the chiller farm or between the cooling equipment and the noise-sensitive receiver. The sound barrier interrupts the direct line-of-sight sound path between the equipment and surrounding property.

Unlike an individual fan silencer, the barrier wall can reduce noise generated by the entire chiller or condenser unit. By surrounding the chiller farm — or positioning the barrier between the equipment and noise-sensitive property lines — a single system can help control:

• Condenser fan noise
• Compressor noise
• Fan intake noise
• Refrigerant and mechanical noise
• Multiple chillers and condensing units simultaneously

Absorptive Sound Barrier Construction

eNoise Control modular steel sound barrier panels are constructed with a solid exterior steel surface and a perforated interior surface facing the equipment, with acoustical absorption material inside the panel. The solid surface provides sound-blocking mass, while the absorptive equipment-side surface reduces reflected sound energy and captures sound generated inside the chiller farm.

This absorptive construction is especially important when chillers are located adjacent to buildings or other reflective surfaces, since it reduces sound reflections between the chillers, building walls and the sound barrier system itself.

Barrier walls can be engineered for the required height and length while maintaining appropriate clearances for equipment airflow, service and maintenance.

Sound Barrier Walls vs. Individual Fan Silencers

Acoustical fan silencers can provide very high attenuation when condenser fan discharge noise is the primary problem. Silencers are engineered around the airflow in CFM and available fan pressure to provide noise reduction while maintaining the required airflow.

However, a large data center may contain dozens or even hundreds of condenser fans. Installing individual silencers requires a silencer for each fan or fan group and may require additional structural steel, since the chiller casing is typically not designed to support the added weight.

An absorptive sound barrier wall can often provide a more economical and comprehensive solution. Instead of treating each fan individually, one sound barrier system can treat multiple chillers and multiple noise sources simultaneously. This can significantly reduce the amount of acoustical equipment and structural support required while addressing fan intake, compressor and mechanical noise that fan silencers alone do not treat.

The result is a durable outdoor noise-control solution that addresses both fan and compressor noise while still allowing the cooling equipment to remain open to the atmosphere for proper airflow and servicing.

When Are Condenser Fan Silencers Required?

Some data center projects require very aggressive sound reduction. In these applications, a combination of absorptive sound barrier walls and condenser fan silencers may provide the best solution.

The sound barrier controls noise radiating horizontally from the complete chiller farm, while acoustical silencers provide additional attenuation of vertically discharged condenser fan noise.

The appropriate solution depends on the equipment sound power levels, number of chillers, equipment arrangement, distance to the property line, surrounding buildings and required sound criteria.

Predictive Data Center Noise Modeling

Before constructing a sound barrier system, eNoise Control can use manufacturer octave-band sound power data and predictive acoustical modeling to estimate sound levels surrounding the proposed data center.

Noise modeling can evaluate the combined contribution of multiple chillers and condensing units and predict sound levels at nearby property lines, residential neighborhoods or other noise-sensitive receivers.

Different sound barrier heights, locations and configurations can then be modeled to determine the appropriate noise control system needed to meet the project’s acoustical objectives before construction begins.

Complete Data Center Chiller Farm Noise Control

Every data center cooling installation is different. The most effective approach is to evaluate the entire chiller farm as one acoustical system rather than simply treating individual condenser fans.

eNoise Control can provide:

• Predictive acoustical sound modeling
• Absorptive steel sound barrier walls
• Condenser fan silencers
• Acoustical louvers
• Compressor noise treatments
• Outdoor acoustical enclosures
• Complete engineered data center noise control systems

For large chiller farms, an absorptive sound barrier wall can provide a cost-effective solution by treating multiple chillers, condenser fans, compressors and mechanical noise sources with one integrated noise control system.

Call eNoise Control today at 888-213-4711 or email info@enoisecontrol.com to discuss your data center chiller farm noise control application.