Improvement manner null of efficiency of the refigerating plant and the refigerating plant which are improved

摘要

PURPOSE: To provide a close heat transfer system including a compressor incorporating a refrigerant-oil composition in which lubricating oil dissolves refrigerant gas facilely at a low pressure and temperature by using a specified refrigerant and a substrate- lubricating material. CONSTITUTION: Non-chlorinated fluorinated hydrocarbon is used as a refrigerant, and polyether polyhydric alcohol or monohydric alcohol is used as a substrate- lubricating material. In a miscibility graph showing solubility characteristics in an operable temperature region of a system, the line x in the upper graph shows the presence of complete immiscibility or insolubility at the upper part of the line, and the line y shows the presence of immiscibility or insolubility of the refrigerant in the oil at temperatures lower than those of compressor operation. For a rotary displacement compressor, ordinary operable temperatures are in the range of +30 deg.C to +90 deg.C, however, operation temperatures higher than those, e.g. even temperatures up to 121 deg.C, are practical and considered to be within the insolubility region of the upper part of the line x. For an evaporator operation ordinary operable temperatures are in the range of -40 deg.C to +20 deg.C, and a soluble region in oil concentration less than 5% enables desired operation of the system.