The efficiency of the air-cooled chiller is dictated by the condensing temperature which may be decreased with increasing heat transfer performance of the condensing coil. Microchannel heat exchangers have become popular in chiller applications due to better thermo-hydraulic characteristics in comparison to conventional fin/tube heat exchanger designs. The most straightforward way to improve heat exchanger performance is to increase its face area by combining two microchannel coils in V form.
Field tests showed that the V-shaped microchannel heat exchangers used in Kaltra’s new ranges of the air-cooled scroll and centrifugal chillers increase the capacity of condensers by 20% at the same footprint. At the same capacity, the new heat exchanger resulted in around a 2K drop in the condensing temperature thereby increasing the chiller efficiency by more than 5%. Thin microchannel coil design translates into significantly lower airside pressure drops, resulting in about 10% reduction in fan power consumption.