Dynamic Noise Control set to revolutionise chiller market as sound becomes key issue

Cool-Therm has launched a revolutionary new system for actively controlling the sound output from air conditioning chillers. Dynamic Noise Control (DNC) guarantees a chiller will not exceed a pre-set noise limit, irrespective of ambient conditions. It is designed to overcome the increasingly stringent requirements on noise produced by building services plant, imposed by local authorities, planners and end users, which can affect the siting and – in many cases – viability of chiller installations. 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 Dynamic Noise Control system 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. 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 Building Management system 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. 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. Ken Strong says: “Given the exceptional energy efficiency of the Turbomiser chiller, which is up to 60 per cent more efficient than conventional chillers, the slight energy penalty incurred with the DNC system is minuscule beside the substantial savings that continue to be delivered by the Turbomiser.” The system also manages all refrigerant safety devices, including high discharge pressure. In the event of high discharge pressure, which can occur if fan speed is reduced in very high load/ambient conditions, the system automatically reduces the compressor load in order to ensure continued safe operation within the noise level set-point. The first Turbomiser project to be equipped with DNC has just been installed in a new building in the heart of London. The 22-storey development houses retail units, offices, premium apartments and a penthouse suite. A key issue for the developer was to ensure that noise from the roof-top mounted chillers was controlled so as not to disturb residents. Two Turbomiser 400kW chillers have been installed on the building’s roof-top, both equipped with the DNC system. Tests conducted on working chillers at Geoclima’s factory proved the system is effective in limiting noise within the pre-set parameters. Ken Strong says: “The rise of noise as an issue for the industry is partly the result of growth in concern over noise pollution generally. It is also the result of people returning to live in city centres, often in apartments located side-by-side with commercial premises. A third factor is the growth in the use of air conditioning overall, with a steep increase in the proportion of commercial and residential buildings that have some form of mechanical cooling.” “We believe that as sensitivity over noise continues to grow, DNC provides the industry with a ready solution and that it will become widely used.” For more details, call 0117 9610006 or email: enquiries@cooltherm.co.uk