capacity modulation, R410A scroll compressor, energy efficiency, two stage compressor, cycling, experiment
Rising cooling needs for the residential and commercial air conditioning sectors and the requirement of higher SEER values increased the focus on energy-efficient part load performance. Although several studies exist on the topic of capacity modulation, there is no comprehensive study that compares different modulation strategies in the same experimental facility. In a first step, this paper aims to experimentally compare two different capacity controls for scroll compressors (single speed vs two-stage compressor) using the same R410A water ethylene glycol (WEG) chiller having a nominal cooling capacity of 8kW. The tests were conducted according to AHRI Standard 551/591 (2018). The Integrated Part Load Value (IPLV.SI) was used to fairly compare all these capacity modulation strategies. Based on the experimental results, the difference in the order of 8% in IPLV.SI is found. While both compressors showed comparable capacities and COPs at the higher modulation conditions, two stage compressor has better COP at the lower condition because of its ability to operate at a lower stage and better meet the required load.