Operation control method null of the air conditioner and its air conditioner which use the non azeotropic mixed refrigerant

摘要

PROBLEM TO BE SOLVED: To avoid stop of operation due to pressure protection upon excessive rising of a pressure and continue the operation, by a method wherein a condensing temperature, whereat a high-pressure switch is not operated, is operated employing a circulating composition ratio obtained by a refrigerant composition ratio operating means to carry out the control of a pressure reducing device. ;SOLUTION: A refrigerant circulating composition ratio is obtained from a condensing temperature and the pressure of a high-pressure switch 9. Successively, saturating temperature of some pressure value, becoming lower than a pressure value set in the high-pressure switch 9, is operated by employing the obtained circulating composition ratio to specify the saturating temperature as a protective condensing temperature. When a given period of time has elapsed successively and a condition that the high- pressure switch is restored or whether an automatic restoring condition is satisfied or not is judged. In this case, when it is judged that the automatic restoring condition is satisfied, a compressor 1 is re-started. Upon this time, an electronic expansion valve 8 is kept in a condition that the same is opened in some degree. Then, the opening degree of an electronic expansion valve 8 is controlled while comparing a subcooling, obtained from condensing temperature-condensing outlet temperature, with an objective subcooling.;COPYRIGHT: (C)1999,JPO