Patent ID: 9217592
Filing Date: 2015-12-22
Classification: F25B

Abstract:
1. A refrigeration system comprising: a compressor, a condenser, an expansion device, an evaporator, and an additional refrigerant vessel connected in a closed refrigerant loop; the additional refrigerant vessel connected to the condenser at a high pressure side by a first valve and to the evaporator at a low pressure side by a second valve; a controller to control operation of the first valve and the second valve, wherein only one of the first valve and the second valve is open at a time to allow additional refrigerant to be added to the closed refrigerant loop in response to the controller receiving a low refrigerant level indication of a refrigerant level in the evaporator, or to remove refrigerant from the closed refrigerant loop in response to the controller receiving a high refrigerant level indication of a refrigerant level in the evaporator, a chamber in fluid communication with the evaporator; and a fluid level sensor disposed within the chamber to provide a direct measurement of the refrigerant level to the controller; the controller configured to: count the number of surges occurring within a predetermined interval; increment a surge count when a surge is indicated; compare the surge count with a surge count threshold; and in response to the surge count exceeding the surge count threshold: observe a liquid refrigerant level in the evaporator with respect to a target refrigerant level; and in response to observing no change in the liquid refrigerant level over the predetermined interval, return to the step of monitoring a parameter associated with the compressor and monitor a motor current for surge indication.