Patent ID: 7146819

Claim:
A method of refrigerant level monitoring in a refrigerant circuit of an air-conditioning or heat-pump system having a compressor and a refrigerant which may, depending on the operating point, be operated in the supercritical range, the method comprising: at least in-operation level monitoring with the compressor switched on, measuring the refrigerant superheat (dTü) at the evaporator of the system, and determining whether the measured superheat (dTü) lies above a predetermined limiting value (dTü G ), as an indication of improper filling, wherein, the refrigerant superheat (dTü) at the evaporator is measured by using the difference between a temperature (T LVA ), measured on the evaporator outlet side, of a medium led over the evaporator for the purpose of cooling the medium, and the refrigerant temperature (T KVE ) measured on the evaporator inlet side.