To develop new reciprocating compressors for air conditioning or refrigeration a new Fortran program was built inorder to compare different technical solutions. This program is adapted to any refrigerant cycle.The data include the refrigerant characteristics, the oil viscosity, the time step, the bore and stroke ratio, the deadvolume, the number of sealing rings, the friction coefficients, the rotation speed, the parts inertia, the spring andvalve characteristics, the shaft and bearing dimensions.The results cover the volumetric efficiency, the isentropic efficiency, the bearing loads, the friction losses and the oilfilm thickness for the bearings.The compressor is considered in terms of sub assemblies with a hierarchy. The first basic elements are the differentsealing rings which are fully described. Each cylinder is associated with a set of sealing rings, an axis, a connectingrod, whose mechanical characteristics are stored. The program processes each cylinder separately and takes intoaccount the positions of the cylinders on the crankshaft and the eccentric orientation. Finally, the loads on the mainbearings are determined knowing the position of the main bearings of the shaft.The valve stiffness and the thermal exchanges with the cylinder can be added to the parameters. The computation ispossible for any number of cylinders and any number of stages of compression, provided that the pistons areconnected to the same shaft.The program was based on a perfect gas model to obtain the efforts on the piston, from which the loads on allbearings were derived.The Fortran language has good portability and allows a subroutine architecture, which is useful to modify theprogram or to add new features. The data can be written into an Excel file and the results can be loaded into anotherExcel file. This program was used to select design criteria and to make decisions. The product development timewas reduced and many lab tests were avoided.
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