EUROPE: Daikin’s next generation EWAD-TZ B chiller is available as a single- or dual-circuit unit, with cooling capacities from 170kW up to 700kW.
Building on its predecessor – the EWAD-TZ launched in 2013 – the latest model combines a screw compressor design and integrated inverter technology with Variable Volume Ratio technology (VVR). This is said to allow compressors to modify their own geometry, varying the condenser pressure charge to maintain the highest compression efficiency.
Daikin says its compressor motors have been optimised to operate at different speeds, with selection of the most efficient motor according to the nominal frequency of the chiller, to ensure the highest unit performance. Improved control logic for the economiser cycle control offers even more advantages and greater reliability.
The advanced design of the heat exchangers uses the latest available technology to deliver a high heat transfer coefficient while minimising pressure drops.
A number of options and accessories allow end users to adjust the new system to their specific needs, says Daikin. Three efficiency levels are offered with ESEERs from 4.4 to 5.5 and three sound levels: standard; low, with special connections at the suction of each compressor to reduce vibration transmission; and reduced with the special compressor connections and the compressors enclosed in a soundproof cabinet.
The EWAD-TZ B chiller incorporates a new epoxy-coated microchannel condenser coil, using R134a and operating with a two-pass process. In the first pass, the high-pressure superheated refrigerant is de-superheated and condensed into a liquid. The second pass sub-cools the liquid refrigerant below its saturation temperature prior to entering an expansion device. This construction is said to provide a coil that is typically 50% lighter and uses, on average, 50% less refrigerant when compared to a traditional copper-tube/aluminium-fin coil design. Heat transfer is also enhanced.