Hermetik pistonlu kompresörün tribolojik analizi

A hermetic reciprocating compressor is one of the most critical parts for the energy efficiency of a household refrigerator. The tribological performance of the compressor's piston-cylinder pair could be enhanced through introducing micro-texture on the compressor's piston surface. In this thesis, an experimental study is presented to tribologically assess the effect of the micro-textured piston on the performance of the hermetically sealed reciprocating compressor. Effects of the micro-dimples texture of the piston on the compressor's coefficient of performance was investigated. Refrigerant leakage from the piston-cylinder clearance was decreased by 35% and the compressor's cooling capacity was observed to be increased slightly. In addition, this thesis also presents a novel solution to the lubrication problem of an inverter-type hermetic reciprocating compressor used in household refrigerators during a low-speed (less than 2000 rpm) operation. The lubrication system is primarily based on an additively manufactured unibody pump. Moreover, the thesis also aims to discuss the development of a cermet material for the manufacturing of piston via a multi-material negative additive manufacturing approach. The suggested methodology entails the layer-by-layer 3D printing of a negative mold geometry. The cermet slurry is cast into the mold gradually as it is built up layer-by-layer simultaneously. The cermet green body is then demolded by dispersing the mold in an organic solvent such as DCM. The multi-material 3D printing approach eliminated the shape retention problem of the slurry-based additive manufacturing system. A piston produced from cermet material through this method is found to be 10 times lighter than a conventional piston.