Critique of the design and operation of sustainable air-cooled chillers in commercial buildings

Where water shortage is concerned, air-cooled chillers are typically installed to provide cooling energy in commercial buildings with significant electricity consumption. This study investigates performance data and technical specifications on a wide range of air-cooled chiller products. The coefficient of performance (COP) of the chillers at full load operation ranges from 2.4 to 3.7, with 2.9, 3.1 and 3.3 in the 25^th, 50^th and 75^th percentiles, respectively. A survey on national standards and guidelines for the energy performance of air-cooled chillers shows that the minimum required COPs lie between 2.4-3.1 at full load operation. This suggests that over 50% of the existing products can meet the requirement and more stringent control should be in place to boost the use of high efficiency chillers. Control algorithms should be further exploited to judge if the chillers operate with desirable performance under part load conditions. Advanced controls are seldom applied to optimize their performance at part load operation.