High efficient 18-90 m3/h R744 compressor

A flexible compressor and heat exchanger test facility has been built and installed in the laboratories of SINTEF and NTNU in Trondheim. It enables a thorough investigation of higher capacity R744 components like compressors, heat exchangers, expansion and work recovery devices. The maximum electrical power input to the compressor is in the range of 100 kW. Various plate heat exchangers are applied as baseline equipment to be able to investigate real system operations from evaporation temperatures around the triple point of R744 to maximum discharge pressures of 130 bar. Single stage R744 compressors with variable volume flow rates in the range of 18 to 90 m3/h are not available in the market. Therefore a novel high efficient, 6 cylinder piston compressor has been developed in close cooperation between SINTEF and OBRIST Engineering. The paper describes briefly the design features of the compressor and the test facility. Initial experimental results show an overall efficiency significantly higher than state-of-the-art compressor concepts with ordinary asynchronous motors. Latest results will be presented and implemented in the paper.