Performance evaluation of air-cooled screw chillers at low part load ratios and outdoor temperatures in Dubai and measures to improve the performance

Abstract

Air-cooled chillers are considered to be intensive energy consumers and account for over one-fourth of the energy consumption in air-conditioned buildings. In Dubai, for about 4-5 months, chillers operate at low part load ratios with a reduced coefficient of performance (COP) due to low outdoor temperatures. This paper evaluates the performance of air-cooled twin-circuit screw chillers serving a medium-scale commercial building in the month of January when the outdoor temperatures are low. The performance of the chillers is analysed in view of calculated parameters and optimal conditions obtained from the readings taken. The chillers are found to be operating poorly at low COPs. Measures to rectify the problems in the performance of the chillers and advanced chiller technologies that are currently under research are discussed.