28 June 2022
Daikin Applied has extended its range of chillers with the introduction of the DWDC C series of centrifugal compressor water-cooled models.
Available in cooling capacities between 1,500 and 2,500kW, the range is said to have been developed to optimise energy efficiency and reduce operating costs. The chillers are designed for use with low global warming refrigerants R134a, R513A, or R1234ze in a single refrigerant circuit and are aimed at commercial cooling, district energy plants, and manufacturing applications.
The dual compressor design delivers impressive part-load efficiency along with system redundancy comparable to operating two separate chillers, but claims a lower total installed cost. The DWDC C can also be equipped with variable speed drives for additional efficiency.
Each chiller has two compressors, two lubrication systems, two control systems, and two starters connected to the evaporator and condenser. If one compressor fails, it can be removed or repaired without shutting down the other so providing an automatic backup with at least 60% of the chiller design capacity still available.
Redundancy is also built into the distributed control system. If a compressor controller is unavailable, the other compressor will operate normally and handle as much of the load as possible. Also, if the chillers are operating at 60% and below, Daikin has programmed the unit controls to allow just one compressor to run leading to lower run hours and reduced wear and tear that will extend the operating life of the equipment.
The flexible control logic of the inverter drive maps exact performance curves at every condition to minimize speed and still deliver the required cooling capacity. This allows the DWDC C chillers to take advantage of off-design conditions to save energy for comfort cooling applications with variable loads – even for data centres with constant heavy demand.
The new series is also supported by a ‘right-sizing’ selection feature so system designers can make best use of the multiple combinations of heat exchangers, gears, and semi-hermetic motors to closely match performance to required capacity and avoid costly over-sizing.
Daikin Applied has also developed a new type of heat exchanger ‘flood’ technology to improve the heat transfer performance and create the best balance between cost and performance. The new chillers can also be set up to take advantage of ‘free cooling’.
By offering refrigerant R1234ze as an option, Daikin Applied is combining low global warming potential (GWP) with high energy efficiency. As an HFO refrigerant its ozone depletion potential is zero and it has a GWP of just seven, as assessed under the European F-Gas Regulation. Therefore, R1234ze(E) is a long-term solution that is unaffected by the HFC phase down timetable.
The DWDC C range is also available with conventional refrigerants R134a and R513A, which will also remain available for use throughout the installed life of these chillers.