Method of refrigeration case control
AssigneeNovar Electronics Corporation
InventorsJames H. Ott, Mark E. Anglin, James P. Henderson
Life of this patent
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Abstract
A method of controlling a refrigeration case of a refrigeration system including the steps of locating an expansion valve of a refrigeration case, moving the expansion valve of the refrigeration case out of a predetermined position, sampling temperature readings from an evaporator coil of a refrigeration case, calculating an adaptive proportional-integral-differential (PID) of the temperature of the evaporator coil for the refrigeration case, and moving the expansion valve to a second position closer to the predetermined position based on the calculated proportional-integral-differential until the temperature of the evaporator coil for the refrigeration case is within a predetermined temperature range.
Claims27
A method of controlling a refrigeration case of a refrigeration system, the method comprising the steps of:
- setting an expansion valve of a refrigeration case to a predetermined position;
- moving the expansion valve of the refrigeration case out of the predetermined position;
- sampling temperature readings from an evaporator coil of the refrigeration case;
- calculating an adaptive proportional-integral-differential (PID) of the temperature of the evaporator coil for the refrigeration case;
- and
- moving the expansion valve to a second position closer to the predetermined position based on the calculated proportional-integral-differential until the temperature of the evaporator coil for the refrigeration case is within a predetermined temperature range.
A method of controlling a refrigeration case of a refrigeration system, said method comprising the steps of:
- determining whether it is time to sample temperature readings from an evaporator coil of a refrigeration case;
- determining whether an expansion valve of the refrigeration case is forced to a predetermined position if it is not time to sample temperature readings;
- positioning the expansion valve of the refrigeration case if the expansion valve of the refrigeration case is forced to the predetermined position;
- calculating an adaptive proportional-integral-differential (PID) of the temperature of the evaporator coil for the refrigeration case if it is time to sample temperature readings;
- and
- positioning the expansion valve for the refrigeration case until the temperature of the evaporator coil for the refrigeration case is within a predetermined temperature range.
Dependencies are inferred from the claim text.