Abstract: A fault detection and diagnostics (FDD) system is provided for a refrigeration circuit having an evaporator and a compressor configured to circulate a refrigerant through the evaporator. The FDD system includes a communications interface configured to receive a measurement of a thermodynamic property affected by the refrigeration circuit and a processing circuit having a processor and memory. The processing circuit is configured to use the measured thermodynamic property to determine an expected suction entropy of the refrigerant at a suction of the compressor, use the expected suction entropy to determine an expected thermodynamic discharge property of the refrigerant at a discharge of the compressor, determine an actual thermodynamic discharge property of the refrigerant at the discharge of the compressor, and detect a fault in the refrigeration circuit by comparing the expected thermodynamic discharge property with the actual thermodynamic discharge property.

Abstract: A method for detecting and cleansing suspect building automation system data is shown and described. The method includes using processing electronics to automatically determine which of a plurality of error detectors and which of a plurality of data cleansers to use with building automation system data. The method further includes using processing electronics to automatically detect errors in the data and cleanse the data using a subset of the error detectors and a subset of the cleansers.

Abstract: A controller for a building management system includes a first data interface configured to receive data from the building management system and a processing circuit including a processor and a memory device storing a fault detection rule having an initial threshold value. The processing circuit is configured to detect a first fault in the building management system using the stored fault detection rule having the initial threshold value and to use the data from the building management system to determine whether an adjustment to the stored fault detection rule is needed. In response to a determination that an adjustment to the stored fault detection rule is needed, the processing circuit is configured to calculate a new threshold value for the stored fault detection rule and update the stored fault detection rule by replacing the initial threshold value with the new threshold value.

Abstract: A controller for a building management system includes a system of rules for detecting faults in the building management system. The rules include content conditions and trigger conditions. The content conditions are not checked until one or more of the trigger conditions are met. A rule-based fault detection engine may be implemented by a low level building equipment controller. One or more thresholds for a rule may be automatically or manually adjusted.

Abstract: A controller for a building management system includes a system of rules for detecting faults in the building management system. The rules include content conditions and trigger conditions. The content conditions are not checked until one or more of the trigger conditions are met. A rule-based fault detection engine may be implemented by a low level building equipment controller. One or more thresholds for a rule may be automatically or manually adjusted.