Low charge detection method for supermarket refrigeration systems

Detection of low refrigeration charge is important to ensure food safety and avoid excessive energy consumption in a refrigeration system. Low charge detection in a supermarket refrigeration system can be achieved by utilizing data from the control system by creating a baseline model of the system dynamics. The work presented will show how a baseline model can be used to identify low refrigerant charge in a supermarket refrigeration system. The method uses fault detection techniques to detect a significant change in refrigeration charge. The method can provide early detection of low refrigeration charge before the refrigeration charge becomes critically low so that the desired temperature can be maintained in the display cabinets. The method has been validated using data from two different supermarkets that have experienced low charge situations.