A Study to Improve Efficiency of a Variable Speed Scroll Compressor

A study using a 1D chamber model was done to improve isentropic efficiency of a variable speed scroll compressor and then testing was conducted to validate. It was noticed in the initial analysis that the economizer location, sizing, and timing optimization gave an efficiency improvement of 0.5–2.5% depending on the operating point. Since the economizer was optimized for location, area and timing or activeness, the back flow was reduced, hence the mass flow through the port and efficiency improved. A study with focus on speed resulted in an improvement in weighted efficiency to the tune of 4–6%. Investigating the effect on port delay showed, improvement was on a rising trend as the discharge port delay was increased until around 110° and then efficiency started to decline. The improvements for different operating conditions were in the range of 2–4%. An improvement in involute start angle also resulted in improvement in efficiency to the tune of 0.7–1.3% depending on the operating condition. Changing this parameter affected the structural integrity, hence not adapted. A new compressor was built with new economizer port geometry to understand the effect. The results were promising with variation in efficiency from − 0.6 to 5.1% for different operating conditions investigated. Speed sweeps showed there are peak efficiency points, which can be used to decide the speed for operating condition.