Abstract: An control method includes obtaining measurements of a carbon dioxide (CO2) level of a zone and a temperature of the zone. The method includes determining, based on the CO2 level of the zone and the temperature of the zone, a combination if (i) control decisions for an air handling unit (AHU) and (ii) control decisions for a damper of a variable air volume (VAV) unit to satisfy both a ventilation control objective and a temperature control objective. The control decisions for the AHU include adjustments to a fresh air intake fraction of the AHU between multiple values over time, and the control decisions for the VAV unit include adjustments to a position of a damper of the VAV unit over time. The method includes operating the AHU according to the control decisions for the AHU and operate the VAV unit according to the control decisions for the VAV unit.

Abstract: An airflow sensor system for an air duct including a damper positioned therein is provided. The controller is configured to determine, via a first pressure sensor, a first airflow measurement based on a first one or more pressure measurements. The controller is further configured to determine, via a second pressure sensor and a damper position sensor, a second airflow measurement based on a second one or more pressure measurements and one or more damper position measurements. The first airflow measurement and the second airflow measurement have a first uncertainty value and a second uncertainty value associated therewith. The controller is further configured to determine an estimated airflow based on weighted values of the first airflow measurement and the second airflow measurement. The weighted values are based on the airflow measurements and the uncertainty values associate therewith.

Abstract: An airflow sensor assembly for an air duct is provided. The airflow sensor assembly includes the air duct having an interior wall and an exterior wall, a high pressure pickup device, a low pressure pickup device, a pressure redirection device, and a pressure sensor. The pressure redirection device is fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a low inlet, a high inlet, and a common outlet. The pressure sensor is selectively fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a first inlet and a second inlet. The second inlet is fluidly coupled to the common outlet of the pressure redirection device.

Abstract: An airflow sensor assembly for an air duct is provided. The airflow sensor assembly includes the air duct having an interior wall and an exterior wall, a high pressure pickup device, a low pressure pickup device, a pressure redirection device, and a pressure sensor. The pressure redirection device is fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a low inlet, a high inlet, and a common outlet. The pressure sensor is selectively fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a first inlet and a second inlet. The second inlet is fluidly coupled to the common outlet of the pressure redirection device.

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: An airflow sensor assembly for an air duct is provided. The airflow sensor assembly includes the air duct having an interior wall and an exterior wall, a high pressure pickup device, a low pressure pickup device, a pressure redirection device, and a pressure sensor. The pressure redirection device is fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a low inlet, a high inlet, and a common outlet. The pressure sensor is selectively fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a first inlet and a second inlet. The second inlet is fluidly coupled to the common outlet of the pressure redirection device.

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 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 refrigerated display case includes a base. A first wall extends from the base and has a first supply air duct defined therein. A second wall extends from the base and has a second supply air duct defined therein. The first wall and the second wall define a product area therebetween. A return air duct is disposed in the product area between the first supply air duct and the second supply air duct. An evaporator coil is disposed in an equipment space defined between the product area and the base. The equipment space is fluidly coupled to the first supply air duct, the second supply air duct, and the return air duct. A first circulation fan is disposed in the equipment space proximate the first supply air duct. A second circulation fan disposed in the equipment space proximate the second supply air duct.

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 for improving performance of an access triggered architecture for a computer implemented application is provided. The method first executes typical operations of the access triggered architecture according to an execution time, wherein the typical operations comprise: obtaining a dataset and an instruction set; and using the instruction set to transmit the dataset to a functional block associated with an operation, wherein the functional block performs the operation using the dataset to generate a revised dataset. The method further creates a pipeline of the typical operations to reduce the execution time of the typical operations, to create a reduced execution time; and executes the typical operations according to the reduced execution time, using the pipeline.

Abstract: In various implementations, frost in a vapor compression system may be controlled. A property of a fan may be determined. A determination may be made whether a frost event and/or a nonfrost event has occurred based at least partially on the determined fan property.

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: Methods and apparatus are provided for a controlled motor assembly for use in a reaction wheel assembly (RWA). The controlled motor assembly is optimized to work with an AC motor, and includes a filter configured to inhibit electrical and electromagnetic noise from being coupled between a spacecraft power bus and a power bus internal to the RWA, as well as an arrangement of power switch elements providing a path for motor phase currents associated with the AC motor. A digital control system is implemented to receive a command input, position sensor feedback and to retrieve parameters associated with the AC motor from a memory device. Based on the command input, the position sensor feedback and the parameters associated with the AC motor, the digital control system controls activation for the arrangement of power switch elements, and generates data output.

Abstract: The present invention provides for a control system for a compressor assembly of an heating, ventilation, and air conditioning (HVAC) system. A control assembly comprises a controller for varying the capacity of a compressor unit of the compressor assembly. The controller determines a first pressure of the compressor unit based on a first operating state of the compressor unit.

Abstract: In various implementations, frost in a vapor compression system may be controlled. A property of a fan may be determined. A determination may be made whether a frost event and/or a nonfrost event has occurred based at least partially on the determined fan property.

Abstract: A method for improving performance of an access triggered architecture for a computer implemented application is provided. The method first executes typical operations of the access triggered architecture according to an execution time, wherein the typical operations comprise: obtaining a dataset and an instruction set; and using the instruction set to transmit the dataset to a functional block associated with an operation, wherein the functional block performs the operation using the dataset to generate a revised dataset. The method further creates a pipeline of the typical operations to reduce the execution time of the typical operations, to create a reduced execution time; and executes the typical operations according to the reduced execution time, using the pipeline.

Abstract: In various implementations, frost in a vapor compression system may be controlled. A property of a fan may be determined. A determination may be made whether a frost event and/or a nonfrost event has occurred based at least partially on the determined fan property.