Abstract: A controller of a heating, ventilation, and air conditioning (HVAC) system, the controller comprising instructions that cause the controller to determine an air flowrate of an air blower of the HVAC system and calculate a threshold value based on a minimum required air flowrate. The controller further comprises instructions that cause the controller to send a notification to an operator of the HVAC system indicating that the air flowrate of the air blower is less than the threshold value in response to determining that the air flowrate of the air blower is less than the threshold value and shut down the HVAC system such that the refrigerant is no longer circulated by the componentry of the HVAC system in response to determining that the air flowrate of the air blower is less than the minimum required air flowrate.

Abstract: An HVAC system includes a controller communicatively coupled to a subcool sensor, an outdoor temperature sensor, a compressor, and a blower of the HVAC system. For a first period of time, the controller periodically determines subcool values. For each determined subcool value, a corresponding compressor speed, outdoor temperature, and blower speed are determined. A baseline database is generated with baseline values associated with normal operation of the HVAC system. Following the first period of time, subcool values are determined based on the subcool signal. For each subcool value, a corresponding compressor speed, outdoor temperature, and blower speed are determined. The controller determines whether each subcool value satisfies a criteria based on the baseline database. If the criteria are not satisfied for at least a threshold time, the system is determined to be operating under a fault condition, and a corresponding alert is transmitted.

Abstract: An HVAC system includes a pressure sensor is disposed in a suction line between a compressor and an indoor heat-exchange coil. The pressure sensor is electrically coupled to a compressor controller. An HVAC controller is electrically coupled to the compressor controller. The HVAC controller is configured to transmit a signal to the compressor controller to activate and de-activate the compressor. The compressor controller is configured to receive a signal from the HVAC controller to activate the compressor, determine a start speed of the compressor, monitor a run time of the compressor, and modulate a speed of the compressor.

Abstract: A controller of a heating, ventilation, and air conditioning (HVAC) system, the controller comprising instructions that cause the controller to determine an air flowrate of an air blower of the HVAC system and calculate a threshold value based on a minimum required air flowrate. The controller further comprises instructions that cause the controller to send a notification to an operator of the HVAC system indicating that the air flowrate of the air blower is less than the threshold value in response to determining that the air flowrate of the air blower is less than the threshold value and shut down the HVAC system such that the refrigerant is no longer circulated by the componentry of the HVAC system in response to determining that the air flowrate of the air blower is less than the minimum required air flowrate.

Abstract: In one embodiment, an HVAC system includes an indoor unit having a furnace, an outdoor heat pump unit having a compressor and an outdoor coil, a refrigerant line coupled to the indoor unit and the outdoor heat pump unit, and a valve coupled to the refrigerant line. The HVAC system further includes one or more controllers operable to determine that the outdoor heat pump unit is in operation during an air conditioning cycle. The controllers are further operable to determine an outdoor temperature and compare the outdoor temperature to a predetermined temperature. The controllers are further operable to initiate a closure of the valve coupled to the refrigerant line and initiate operation of the compressor at an end of the air conditioning cycle to pump down a refrigerant to the outdoor coil in response to comparing the outdoor temperature to the predetermined temperature.

Abstract: An HVAC system includes a controller communicatively coupled to a subcool sensor, an outdoor temperature sensor, a compressor, and a blower of the HVAC system. For a first period of time, the controller periodically determines subcool values. For each determined subcool value, a corresponding compressor speed, outdoor temperature, and blower speed are determined. A baseline database is generated with baseline values associated with normal operation of the HVAC system. Following the first period of time, subcool values are determined based on the subcool signal. For each subcool value, a corresponding compressor speed, outdoor temperature, and blower speed are determined. The controller determines whether each subcool value satisfies a criteria based on the baseline database. If the criteria are not satisfied for at least a threshold time, the system is determined to be operating under a fault condition, and a corresponding alert is transmitted.

Abstract: An HVAC system includes a pressure sensor is disposed in a suction line between a compressor and an indoor heat-exchange coil. The pressure sensor is electrically coupled to a compressor controller. An HVAC controller is electrically coupled to the compressor controller. The HVAC controller is configured to transmit a signal to the compressor controller to activate and de-activate the compressor. The compressor controller is configured to receive a signal from the HVAC controller to activate the compressor, determine a start speed of the compressor, monitor a run time of the compressor, and modulate a speed of the compressor.

Abstract: In one embodiment, an HVAC system includes an indoor unit having a furnace, an outdoor heat pump unit having a compressor and an outdoor coil, a refrigerant line coupled to the indoor unit and the outdoor heat pump unit, and an EEV coupled to the refrigerant line. The HVAC system further includes one or more controllers operable to determine an occurrence of a first event, initiate a closure of the EEV, initiate operation of the compressor at a completion of the air conditioning cycle to pump down a refrigerant to the outdoor coil, and cease operation of the compressor when a low-pressure switch is tripped.

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: An HVAC system includes a pressure sensor is disposed in a suction line between a compressor and an indoor heat-exchange coil. The pressure sensor is electrically coupled to a compressor controller. An HVAC controller is electrically coupled to the compressor controller. The HVAC controller is configured to transmit a signal to the compressor controller to activate and de-activate the compressor. The compressor controller is configured to receive a signal from the HVAC controller to activate the compressor, determine a start speed of the compressor, monitor a run time of the compressor, and modulate a speed of the compressor.

Abstract: In one embodiment, an HVAC system includes an indoor unit having a furnace, an outdoor heat pump unit having a compressor and an outdoor coil, a refrigerant line coupled to the indoor unit and the outdoor heat pump unit, and an EEV coupled to the refrigerant line. The HVAC system further includes one or more controllers operable to determine an occurrence of a first event, initiate a closure of the EEV, initiate operation of the compressor at a completion of the air conditioning cycle to pump down a refrigerant to the outdoor coil, and cease operation of the compressor when a low-pressure switch is tripped.

Abstract: A method of minimizing components of a heating, ventilation, and air conditioning (HVAC) system from malfunctioning, the method includes measuring, by an accelerometer associated with at least one component of the HVAC system, vibration of the at least one component and receiving, by a controller, actual vibration data reflective of the measured vibration. The method further includes determining, using the controller, whether the actual vibration data is greater than pre-defined acceptable baseline vibration data by more than a pre-defined acceptable amount and responsive to a positive determination in the determining step, adding, by the controller, as a deadband frequency, an operational frequency of the at least one component corresponding to the actual vibration data.

Abstract: In one embodiment, an HVAC system includes an indoor unit having a furnace, an outdoor heat pump unit having a compressor and an outdoor coil, a refrigerant line coupled to the indoor unit and the outdoor heat pump unit, and a valve coupled to the refrigerant line. The HVAC system further includes one or more controllers operable to determine that the outdoor heat pump unit is in operation during an air conditioning cycle. The controllers are further operable to determine an outdoor temperature and compare the outdoor temperature to a predetermined temperature. The controllers are further operable to initiate a closure of the valve coupled to the refrigerant line and initiate operation of the compressor at an end of the air conditioning cycle to pump down a refrigerant to the outdoor coil in response to comparing the outdoor temperature to the predetermined temperature.

Abstract: According to certain embodiments, operating an HVAC system comprises receiving zone temperature data from a temperature sensor, zone humidity-ratio data from a humidity sensor, a temperature set point from a user, and a relative-humidity set point from a user. A humidity-ratio set point is determined based on the temperature and relative-humidity set points. A first command to the HVAC system to perform a cooling operation is communicated upon determining that the temperature data exceeds a temperature threshold based on the temperature set point. Determining if the humidity data has reached a humidity-ratio threshold based on the humidity-ratio set point after determining that the temperature data has reached the temperature threshold. Operating the HVAC system according to a dehumidification-based cooling procedure upon determining that the humidity data has not reached the humidity-ratio threshold.

Abstract: A controller of a heating, ventilation, and air conditioning (HVAC) system, the controller comprising instructions that cause the controller to determine an air flowrate of an air blower of the HVAC system and calculate a threshold value based on a minimum required air flowrate. The controller further comprises instructions that cause the controller to send a notification to an operator of the HVAC system indicating that the air flowrate of the air blower is less than the threshold value in response to determining that the air flowrate of the air blower is less than the threshold value and shut down the HVAC system such that the refrigerant is no longer circulated by the componentry of the HVAC system in response to determining that the air flowrate of the air blower is less than the minimum required air flowrate.

Abstract: An HVAC system for a comfort zone includes a compressor, temperature sensor and controller. The controller is configured to receive a starting temperature from the temperature sensor, receive a desired temperature, and receive a desired time for the comfort zone to reach the desired temperature. The controller is further configured to determine a starting time to adjust cooling the comfort zone, the starting time determined based at least on the desired time, the desired temperature, the starting temperature, and a most-energy-efficient operating speed of the compressor. Once the starting time has been reached, the controller is further configured to communicate a command to the HVAC system to operate the compressor at the most-energy-efficient operating speed.

Abstract: An HVAC system for a comfort zone includes a compressor, temperature sensor and controller. The controller is configured to receive a starting temperature from the temperature sensor, receive a desired temperature, and receive a desired time for the comfort zone to reach the desired temperature. The controller is further configured to determine a starting time to adjust cooling the comfort zone, the starting time determined based at least on the desired time, the desired temperature, the starting temperature, and a most-energy-efficient operating speed of the compressor. Once the starting time has been reached, the controller is further configured to communicate a command to the HVAC system to operate the compressor at the most-energy-efficient operating speed.

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: According to certain embodiments, operating an HVAC system comprises receiving zone temperature data from a temperature sensor, zone humidity-ratio data from a humidity sensor, a temperature set point from a user, and a relative-humidity set point from a user. A humidity-ratio set point is determined based on the temperature and relative-humidity set points. A first command to the HVAC system to perform a cooling operation is communicated upon determining that the temperature data exceeds a temperature threshold based on the temperature set point. Determining if the humidity data has reached a humidity-ratio threshold based on the humidity-ratio set point after determining that the temperature data has reached the temperature threshold. Operating the HVAC system according to a dehumidification-based cooling procedure upon determining that the humidity data has not reached the humidity-ratio threshold.