Patent ID: 9568226
Date: 2017-02-14
CPC Classifications: F25B

Claim:
1. A method for indicating a level of refrigerant charge in a refrigerant vapor compression system having a compressor, a condenser coil, an expansion device and an evaporator coil connected in serial relationship in refrigerant flow circuit, comprising: sensing a pressure of the refrigerant leaving the condenser coil and generating a first signal indicative of a sensed refrigerant pressure; sensing a temperature of the refrigerant downstream of the condenser coil and upstream of the expansion device and generating a second signal indicative of a sensed refrigerant temperature; calculating in real-time a real-time value for the degrees of subcooling present based upon the sensed refrigerant pressure and the sensed refrigerant temperature; outputting an electrical signal indicative of the real-time value for the degrees of subcooling present; calculating an average value for the degrees of subcooling over a preselected time period of system operation; and outputting an indication of a refrigerant charge status over the preselected time period of system operation based on a step consisting of comparing the average value for the degrees of subcooling over the preselected time period to a threshold; wherein said outputting the electrical signal indicative of the real-time value for the degrees of subcooling present comprises outputting a milli-volt electrical signal indicative of the real-time value for the degrees of subcooling present.