Comparison of energy-efficiency and size of portable oil-free screw and scroll compressors

Abstract

This paper presents test data and evaluates if conical screw compressors can become a preferred alternative to scroll compressors in small oil-free duties from 0.04 to 15kW. The conical screw compressor is a new modification of the conventional screw compressor. A 2kW water-injected conical compressor demonstrated a 34% better energy efficiency than a scroll compressor of similar capacity. At 8 bar(g) load, the conical machine used 13% more energy and produced 42% more flow. Size of the conical screw package is 46% of the scroll package. The miniature conical screw package, at 40W rated power, achieved a pressure of 8 bar(g) in water-injected operation. It can be concluded that the conical screw compressor would be an attractive alternative in micro and small oil-free applications.