Development of Large Capacity And High Efficiency Rotary Compressor

The authors had studied some elemental technologies to realize the large capacity and high efficiency in rotary compressor in order to achieve energy and material resource savings as well as in weight reduction of heat pump systems. Those elemental technologies are the cylinder dimension optimization, the new discharge structure, the divided vane structure, and the compatibility between sliding loss reduction and securing reliability in journal bearings. The new discharge structure is a structure in which two discharge ports are installed per cylinder. The discharge ports are designed with different in cross-sectional area and the responsiveness of each discharge valve is also optimized. By applying the new discharge structure, discharge losses drastically reduced during compression process. The divided vanes structure which splits the vane in the axial direction to reduce force due to the pressure difference per each vane enables to avoid the increasing risk at local contact surface pressure on vane. The journal bearing designs are optimized by using structural analysis. Enhanced shaft stiffness and appropriate journal bearing design contribute to sliding friction reduction and high reliability assurance. By adopting those technologies, we succeeded in developing a new compressor that can increase to the maximum refrigeration capacity 20 HP [60kW]. Compared to our conventional large model, the new model has 1.7 times larger maximum capacity, and about 6 % higher COP ratio in most operation condition range. Moreover, by the more compact and lighter weight of 38.2 kg, the new one has contributed to resource saving and weight reduction of the heat pump unit system. We commercialized this developed compressor for our latest air-cooled module heat pump unit “Universal Smart X Edge Series” which expanded up to 70HP in rated cooling capacity and achieved “IPLV 6.0” at 60 HP heat pump unit systems