Abstract: A refrigeration system includes a valve and a controller. The valve is configured to control the flow of refrigerant into an evaporator, the refrigerant having an associated liquid setting comprising a temperature and a pressure at which the refrigerant flows through the valve. The controller is operable to adjust the liquid setting, the adjusted liquid setting comprising a temperature and a pressure selected to improve energy efficiency under conditions currently being experienced by the refrigeration system, wherein the controller is operable to adjust the temperature and the pressure simultaneously such that the adjustment does not interfere with operation of the valve.

Abstract: A refrigeration system includes a valve and a controller. The valve is configured to control the flow of refrigerant into an evaporator, the refrigerant having an associated liquid setting comprising a temperature and a pressure at which the refrigerant flows through the valve. The controller is operable to adjust the liquid setting, the adjusted liquid setting comprising a temperature and a pressure selected to improve energy efficiency under conditions currently being experienced by the refrigeration system, wherein the controller is operable to adjust the temperature and the pressure simultaneously such that the adjustment does not interfere with operation of the valve.

Abstract: A method of generating an alarm based on temperature conditions within an enclosed space. The method includes receiving, by a processor of a heating, ventilation, and air conditioning (HVAC) system, operating-condition information of the HVAC system, determining, by the processor from the received operating-condition information, whether temperature within the enclosed space is approaching a setpoint temperature. Responsive to a determination that the temperature within the enclosed space has failed to approach the setpoint temperature, determining by the processor, whether anomaly conditions exist and responsive to a determination that the anomaly conditions do not exist, generating the alarm.

Abstract: A method of generating an alarm based on temperature conditions within an enclosed space. The method includes receiving, by a processor of a heating, ventilation, and air conditioning (HVAC) system, operating-condition information of the HVAC system, determining, by the processor from the received operating-condition information, whether temperature within the enclosed space is approaching a setpoint temperature. Responsive to a determination that the temperature within the enclosed space has failed to approach the setpoint temperature, determining by the processor, whether anomaly conditions exist and responsive to a determination that the anomaly conditions do not exist, generating the alarm.

Abstract: A heating, ventilation, and air-conditioning (HVAC) system comprises an outdoor unit with a fan and a coil, and a controller communicatively coupled to the fan and coil. The controller is operable to receive feedback data from the fan, where the feedback data from the fan corresponds to a power and a speed of the fan. The controller is further operable to store a fan model and a plurality of thresholds and determine a virtual sensor measurement, based at least in part upon the feedback data from the fan and the fan model. The controller is operable to determine that the virtual sensor measurement is greater than a frost threshold or a fouling threshold. The controller is finally operable to, in response to determining that the pressure difference is greater than the frost threshold or the fouling threshold, determine a blocked condition on the coil.

Abstract: A refrigeration system includes a compressor, one or more sensors, and a controller. The one or more sensors are operable to sense data associated with the operation of the refrigeration system. The controller is operable to receive the data associated with the operation of the refrigeration system from the one or more sensors, determine an ideal output value of the compressor based at least on data associated with the operation of the refrigeration system, and determine, based at least on the data associated with the operation of the refrigeration system and the ideal output variable, that the performance of the compressor is abnormal.

Abstract: A method for a refrigeration system includes receiving a temperature difference (TD) setpoint indicating a desired temperature difference between outside air and refrigerant and modifying the TD setpoint based on conditions currently being experienced by the refrigeration system. The modified TD setpoint is selected to cause a decrease in total power consumption, wherein the total power consumption comprises power consumed by a compressor to yield a discharge pressure and power consumed by a condenser fan to operate a fan speed.

Abstract: A refrigeration system includes a valve and a controller. The valve is configured to control the flow of refrigerant into an evaporator, the refrigerant having an associated liquid setting comprising a temperature and a pressure at which the refrigerant flows through the valve. The controller is operable to adjust the liquid setting, the adjusted liquid setting comprising a temperature and a pressure selected to improve energy efficiency under conditions currently being experienced by the refrigeration system, wherein the controller is operable to adjust the temperature and the pressure simultaneously such that the adjustment does not interfere with operation of the valve.

Abstract: A refrigeration system includes at least one compressor, a condenser, one or more sensors, and a controller. The one or more sensors are operable to sense data associated with the refrigeration system. The controller is operable to receive operating data associated a first control variable and a second control variable, the operating data received from the one or more sensors. The controller is further operable to determine, based on the operating data, that a control objective is not met, and operate the refrigeration system according to a configuration selected to cause the control objective to be met in response to determining that the control objective is not being met, wherein operating the refrigeration system according to the configuration selected to cause the control objective to be met comprises overriding control of the second control variable until the control objective is met.

Abstract: A refrigeration system includes compressors and a controller. The controller is operable to receive information associated with a load of the refrigeration system and information associated with the compressors. The controller is also operable to determine a first efficiency value and a second efficiency value based on the information associated with the compressors, wherein the first efficiency value is associated with allocating the load among one or more of the compressors according to a first compressor staging and the second efficiency value is associated with allocating the load among one or more of the compressors according to a second compressor staging. The controller is also operable to operate the compressors with the load allocated according to the compressor staging associated with the more efficient efficiency value.

Abstract: A method of initiating a defrost cycle using a controller of a heat pump system includes measuring a temperature of an evaporator coil and determining whether the temperature of the evaporator coil is less than a freezing temperature. Responsive to a determination that the temperature of the evaporator coil is less than the freezing temperature, determining whether a current dew point temperature of air is greater than the temperature of the evaporator coil. Responsive to a determination that the current dew point temperature of air is greater than the temperature of the evaporator coil, calculating a frost-collection rate. Determining whether the frost-collection rate is greater than a frost-collection-rate threshold, and, responsive to a determination that the frost-collection rate is greater than the frost-collection-rate threshold, initiating a defrost cycle.

Abstract: A heating, ventilation, and air-conditioning (HVAC) system comprises an outdoor unit with a fan and a coil, and a controller communicatively coupled to the fan and coil. The controller is operable to receive feedback data from the fan, where the feedback data from the fan corresponds to a power and a speed of the fan. The controller is further operable to store a fan model and a plurality of thresholds and determine a virtual sensor measurement, based at least in part upon the feedback data from the fan and the fan model. The controller is operable to determine that the virtual sensor measurement is greater than a frost threshold or a fouling threshold. The controller is finally operable to, in response to determining that the pressure difference is greater than the frost threshold or the fouling threshold, determine a blocked condition on the coil.

Abstract: A method of generating an alarm based on temperature conditions within an enclosed space. The method includes receiving, by a processor of a heating, ventilation, and air conditioning (HVAC) system, operating-condition information of the HVAC system, determining, by the processor from the received operating-condition information, whether temperature within the enclosed space is approaching a setpoint temperature. Responsive to a determination that the temperature within the enclosed space has failed to approach the setpoint temperature, determining by the processor, whether anomaly conditions exist and responsive to a determination that the anomaly conditions do not exist, generating the alarm.