Dynamic noise control for chillers

ACR Show 2014 Preview: Cool-Therm’s exhibits include the latest innovation in chiller sound attenuation technology, Dynamic Noise Control (DNC), a new range of AHUs and an HFO Turbomiser chiller.

Cool-Therm's Dynamic Noise Control unit mounted on a Turbomiser chiller
Cool-Therm’s Dynamic Noise Control unit mounted on a Turbomiser chiller

DNC actively controls the sound produced by air conditioning chillers, guaranteeing it will not exceed a pre-set noise limit, irrespective of ambient conditions.

DNC constantly monitors sound levels produced by a chiller. If a pre-set noise limit is reached, it actively controls and adapts chiller operation to reduce sound levels – while maintaining chiller output, to ensure cooling to the building is maintained.

Ken Strong, managing director of Cool-Therm, says: “Sensitivity over noise produced by externally-sited air conditioning plant is now a hot issue in many city centres and built-up areas. Dynamic Noise Control addresses the problem of noise produced by air conditioning chillers, and offers a cost-effective solution.”

The system consists of a microphone and sound processing system mounted on the chiller or at a suitable remote location from the chiller (say, in the direction of residential buildings), and is linked and integrated into the chiller controls.

Chiller noise levels are continuously measured and recorded on the chiller display. Readings can also be routed to an external BMS via Modbus, for real-time monitoring.

The maximum permitted noise level can be activated or deactivated for specific time-windows during the day, as in a time clock, to provide “noise assurance” for particularly sensitive times, for example at night.

When in noise-limiting mode, if chiller sound output reaches the set-point the DNC will automatically adapt and balance the speed control of (primarily) fans and (secondarily) the compressor, as needed, to keep the noise level below the set-point.

The algorithm controlling the operation of DNC is designed to deliver the predetermined sound levels as the priority, while reducing as far as possible the impact on cooling capacity (second priority) and energy performance (third priority).

Tests show that, in practice, sound levels can be delivered in most cases with only a tiny sacrifice in energy efficiency and no reduction in cooling capacity.

A Turbocor compressor on the new Turbomiser HFO chiller
A Turbocor compressor on the new Turbomiser HFO chiller

It has been developed as an accessory that can be factory-fitted or retrofitted to Turbomiser chillers, or indeed any chiller which has a compatible control system.

Cool-Therm will also be promoting its new range of high efficiency air handling units following an agreement with Austrian company Clima Tech.

The Clima Tech range joins Cool-Therm’s growing stable of high efficiency hvacr equipment, and complements its award-winning Turbomiser chiller to offer a complete chilled water and air handling solution.

The company will also promote the availability of an HFO version of the Turbomiser chiller, providing a very low GWP option for end users looking to “future-proof” their installations.

cooltherm-logoCool-Therm (UK) Ltd
Unit 5 Trubody’s Yard,
121 London Rd,
Bristol BS30 5NA
Tel: 0117 9610006
Fax : 0117 9478642
[email protected]

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