Effective strategies to manage and minimise rooftop chiller noise

Rooftop chillers are essential for maintaining comfortable temperatures in large buildings. Yet their noise can often become a nuisance, for staff, customers, and the general public alike.

In this blog, the Flexshield team will explore the types of noise emitted by these units and provide practical strategies to control their sound emissions effectively.

What types of noise do rooftop chillers make?

Rooftop chillers generate a range of noises, each with different characteristics and frequency ranges. These include:

1) Mechanical noise

– Compressor noise: Often producing a low-frequency hum or rumble, compressor noise typically runs between 50 and 300 Hz.

– Fan noise: The fans responsible for expelling hot air create a whooshing or roaring sound from 500 to 2,000 Hz.

– Pump noise: Pumps circulating refrigerant or water can generate a droning or vibrating noise, usually between 100 and 500 Hz.

2) Airborne noise

– Airflow noise: This includes moving air, usually from 1,000 to 3,000 Hz, with a constant whoosh.

– Cavitation noise: Disturbances in refrigerant flow may produce bubbling or gurgling sounds, typically from 1,000 to 5,000 Hz.

3) Structural noise

– Vibration transmission: Low-frequency vibrations, ranging from 10 Hz to several hundred Hz, can be transmitted through building structures, causing rumbling or thumping noises. 

4) Operational noise

– Startup and shutdown sounds: During equipment operation changes, these noises can vary from low-frequency thumps (50 to 100 Hz) to higher-frequency clunks (up to 1,000 Hz).

– Cycling noise: Includes low and mid-frequency components, ranging from 50 to 2,000 Hz.

5) High-frequency noise

– Whining or hissing: High-speed components can produce high-pitched whining or hissing sounds from 2,000 to 10,000 Hz.

Common complaints about chiller noise

Businesses often receive several types of complaints regarding chiller noise. These include:

• Employee distraction: Chiller noise can be a major distraction for staff, affecting their concentration and reducing productivity.
• Customer discomfort: For businesses with customer-facing operations, chiller noise can detract from the overall customer experience.
• Building occupants: Noise may disrupt other building areas, such as conference rooms and offices.
• Health concerns: Prolonged exposure to high noise levels can raise health concerns, including potential hearing damage.
• Surrounding areas: External noise may affect nearby residential or public spaces.
• Equipment issues: Unusual or increased noise may signal mechanical problems or a need for maintenance.
• Event interference: Noise can disrupt events or activities held within the building.
• Regulatory compliance: Failing to meet local noise regulations can lead to legal and financial consequences.

Effective noise control strategies for rooftop chillers

To manage and reduce chiller noise, consider the following strategies:

1) Installing acoustic enclosures around the chiller units to contain and absorb noise. These enclosures can be customised for proper ventilation while minimising noise emissions.

2) Using acoustic louvres to control noise while maintaining necessary airflow around the chiller.

3) Erecting sound barriers made of soundproofing materials to block direct noise paths and minimise noise impact.

4) Attaching sound-absorbing acoustic panels to nearby surfaces to mitigate reflected noise and improve acoustic comfort.

Get expert advice on noise control solutions for chillers

By understanding the types of noise associated with rooftop chillers and implementing effective noise control measures, businesses can enhance comfort and compliance while ensuring a quieter environment for everyone involved. Proper noise management of chillers improves the overall experience and supports equipment longevity and operational efficiency.

For more information on reducing noise from your chiller unit, contact Flexshield on 1300 799 969.