Force assisted discharge valve for piston compressors

Abstract

Due to the enormous number of domestic refrigeration appliances worldwide and the associated high overall energy demand of the cooling sector, manufacturers are required to develop more efficient cooling devices. For this reason, variable speed compressors are increasingly being used in order to better match refrigeration demand and supplied cooling capacity. However, variable speed operation is associated with challenges concerning the valve dynamics. Valve oscillation as well as opening and closing delays reduce the energy efficiency (COP) of the compressor.The underlying study is about a simulation based potential analysis of a novel force assisted discharge valve to improve the valve dynamics of a small hermetic reciprocating compressor for domestic refrigeration. Discharge valve and valve support mechanism are modelled by a 1d-spring-damper-mass multi-body system and implemented in an existing in-house compressor simulation model.Systematic methods of statistical design of experiments (DOE) are applied not only to improve the COP but also to generate a robust valve behaviour which is largely independent of the operating conditions of the compressor. The findings of the force assisted discharge valve are basically transferable to any other piston compressor with flutter valves.