Abstract: An HVAC system configured to regulate a temperature of a target space includes an air quality sensor circuit configured to sense a concentration of a contaminant in the target space, at least one room sensor circuit configured to measure a temperature of the target space, and a duct system having an outdoor ventilation inlet, a return air inlet, an exhaust air outlet, and a supply air outlet. A blower moves a return airflow across a first heat exchanger to produce a first conditioned airflow delivered to the target space. A memory stores a total capacity of the HVAC system and a contaminant concentration threshold.

Abstract: An HVAC system includes an evaporator coil, a compressor, and a sensor housing positioned upstream of the evaporator coil. The sensor housing contains a gas sensor configured to measure a concentration of total volatile organic compounds (TVOCs) in an airflow. A controller receives TVOC concentration measurements and operates the HVAC system in a normal operating mode that conditions air for a space. When the measured TVOC concentration exceeds a first threshold, the controller transitions the HVAC system to a ventilation mode in which air is introduced into and discharged from the system to reduce contaminant levels. If the TVOC concentration exceeds a second, higher threshold, the controller generates a notification indicating that an external source of TVOCs may be present. The system enables automated monitoring of indoor air quality and adaptive HVAC operation based on detected contaminant levels.

Abstract: The disclosure provides a method of operating a (HVAC) system. The method includes measuring a concentration of a gas in the target space, and determining that the concentration exceeds a gas concentration threshold. The method includes determining that operation of the HVAC system in a ventilation mode is indicated to reduce the concentration of the gas. The method includes determining a total capacity of the HVAC system, and determining a current capacity of the HVAC system. The method includes causing the HVAC system to operate in the ventilation mode after validating that the total capacity is greater than the current capacity during operation of the HVAC system in the ventilation mode.

Abstract: A controller is configured to operate a heating, ventilation, and air conditioning (HVAC) system based on a plurality of concentration measurements received from a gas sensor, wherein the gas sensor is disposed within a sensor housing upstream of an evaporator coil. The controller is configured to receive the plurality of concentration measurements and determine if a concentration of total volatile organic compounds (TVOCs) in an airflow exceeds a first threshold value. The controller is further configured to operate the HVAC system in a second mode of operation to increase ventilation in response to determining that the concentration of TVOCs in the airflow does exceed the first threshold value, wherein a volume of air is introduced into and discharged from the HVAC system during the second mode of operation.

Abstract: An air quality measuring device that includes a first chamber, a second chamber, a third chamber, and a fourth chamber. The first chamber includes a first inlet configured to receive a first airflow, a first outlet configured to receive a first portion of the first airflow, and a second outlet configured to receive a second portion of the first airflow. The second chamber includes a second inlet configured to receive the first portion of the first airflow and a first sensor disposed within the second chamber. The third chamber includes a third inlet configured to receive the second portion of the first airflow and a second sensor disposed within the third chamber. The fourth chamber includes a fourth inlet configured to receive the second portion of the first airflow and a third sensor disposed within the fourth chamber.

Abstract: An HVAC system includes one or more air quality sensors, each configured to measure an air quality and a thermostat communicatively coupled to the one or more air quality sensors. The thermostat receives indoor air quality measurements from the one or more air quality sensors. An indoor air quality score is determined based at least in part on the received indoor air quality measurements. The thermostat determines, based at least in part on the indoor air quality score, a mitigation action, wherein the mitigation action comprises one or more actions selected from the group of: (i) a filtering action comprising filtering air provided to the space using an air purification subsystem, and (ii) a ventilation action comprising ventilating the space using a ventilation subsystem. The mitigation action is executed, or implemented, by adjusting one or more components of the HVAC system.

Abstract: A heating, ventilating, and air conditioning (HVAC) system includes at least one indoor air quality monitor. The indoor air quality monitor is formed with an arrangement of chambers—intake chamber, low-flow chamber, and outlet chamber—such that a particulate sensor on an interior and another air quality sensor are neither overwhelmed nor underwhelmed by air flow to the sensors. The indoor air quality monitor may be arranged for attaching to a surface in a conditioned space for sampling air therein or may include a bypass chamber that fluidly couples to an HVAC duct.

Abstract: A controller is configured to operate a heating, ventilation, and air conditioning (HVAC) system based on a measurement of a detected quantity of particulate matter from an air quality sensor in relation to a threshold value.

Abstract: A controller is configured to operate a heating, ventilation, and air conditioning (HVAC) system based on a first plurality of particulate matter measurements and a second plurality of particulate matter measurements. The controller is configured to determine an air filter efficiency for an air filter based on the received first plurality of particulate matter measurements and the received second plurality of particulate matter measurements. The controller is further configured to determine if a quantity of particulate matter in an airflow exceeds a first threshold value based on the received second plurality of particulate matter measurements. In response to determining that the quantity of particulate matter in the airflow does exceed the first threshold value, the controller is configured to transmit a notification indicating an action to inspect the air filter.

Abstract: The disclosure provides a method of operating a (HVAC) system. The method includes measuring a concentration of a gas in the target space, and determining that the concentration exceeds a gas concentration threshold. The method includes determining that operation of the HVAC system in a ventilation mode is indicated to reduce the concentration of the gas. The method includes determining a total capacity of the HVAC system, and determining a current capacity of the HVAC system. The method includes causing the HVAC system to operate in the ventilation mode after validating that the total capacity is greater than the current capacity during operation of the HVAC system in the ventilation mode.

Abstract: An air quality measuring device that includes a first chamber, a second chamber, a third chamber, and a fourth chamber. The first chamber includes a first inlet configured to receive a first airflow, a first outlet configured to receive a first portion of the first airflow, and a second outlet configured to receive a second portion of the first airflow. The second chamber includes a second inlet configured to receive the first portion of the first airflow and a first sensor disposed within the second chamber. The third chamber includes a third inlet configured to receive the second portion of the first airflow and a second sensor disposed within the third chamber. The fourth chamber includes a fourth inlet configured to receive the second portion of the first airflow and a third sensor disposed within the fourth chamber.

Abstract: An indoor air quality monitor for an HVAC system includes a monitor body formed with a plurality of chambers defined at least in part by chamber walls. A bypass chamber allows for a majority of airflow entering the monitor to pass through. An intake chamber coupled to the bypass chamber allows for a portion of air to be removed for sampling by a particulate sensor. Air from the particulate sensor is discharged to an outlet chamber that is fluidly coupled to a downstream portion of the bypass chamber. The fluid requirements of the particulate sensor are maintained without overwhelming or underwhelming the particulate sensor.

Abstract: An air quality measuring device that includes a first chamber, a second chamber, a third chamber, and a fourth chamber. The first chamber includes a first inlet configured to receive a first airflow, a first outlet configured to receive a first portion of the first airflow, and a second outlet configured to receive a second portion of the first airflow. The second chamber includes a second inlet configured to receive the first portion of the first airflow and a first sensor disposed within the second chamber. The third chamber includes a third inlet configured to receive the second portion of the first airflow and a second sensor disposed within the third chamber. The fourth chamber includes a fourth inlet configured to receive the second portion of the first airflow and a third sensor disposed within the fourth chamber.

Abstract: A controller is configured to operate a heating, ventilation, and air conditioning (HVAC) system based on a first plurality of particulate matter measurements and a second plurality of particulate matter measurements. The controller is configured to determine an air filter efficiency for an air filter based on the received first plurality of particulate matter measurements and the received second plurality of particulate matter measurements. The controller is further configured to determine if a quantity of particulate matter in an airflow exceeds a first threshold value based on the received second plurality of particulate matter measurements. In response to determining that the quantity of particulate matter in the airflow does exceed the first threshold value, the controller is configured to transmit a notification indicating an action to inspect the air filter.

Abstract: A controller is configured to operate a heating, ventilation, and air conditioning (HVAC) system based on a plurality of concentration measurements received from a gas sensor, wherein the gas sensor is disposed within a sensor housing upstream of an evaporator coil. The controller is configured to receive the plurality of concentration measurements and determine if a concentration of total volatile organic compounds (TVOCs) in an airflow exceeds a first threshold value. The controller is further configured to operate the HVAC system in a second mode of operation to increase ventilation in response to determining that the concentration of TVOCs in the airflow does exceed the first threshold value, wherein a volume of air is introduced into and discharged from the HVAC system during the second mode of operation.

Abstract: A heating, ventilating, and air conditioning (HVAC) system includes at least one indoor air quality monitor. The indoor air quality monitor is formed with an arrangement of chambers—intake chamber, low-flow chamber, and outlet chamber—such that a particulate sensor on an interior and another air quality sensor are neither overwhelmed nor underwhelmed by air flow to the sensors. The indoor air quality monitor may be arranged for attaching to a surface in a conditioned space for sampling air therein or may include a bypass chamber that fluidly couples to an HVAC duct. Other systems and methods are presented.

Abstract: An indoor air quality monitor for an HVAC system includes a monitor body formed with a plurality of chambers defined at least in part by chamber walls. A bypass chamber allows for a majority of airflow entering the monitor to pass through. An intake chamber coupled to the bypass chamber allows for a portion of air to be removed for sampling by a particulate sensor. Air from the particulate sensor is discharged to an outlet chamber that is fluidly coupled to a downstream portion of the bypass chamber. The fluid requirements of the particulate sensor are maintained without overwhelming or underwhelming the particulate sensor. Other systems and monitors are presented; some include separate TVOC sensors.

Abstract: An HVAC system includes one or more air quality sensors, each configured to measure an air quality and a thermostat communicatively coupled to the one or more air quality sensors. The thermostat receives indoor air quality measurements from the one or more air quality sensors. An indoor air quality score is determined based at least in part on the received indoor air quality measurements. The thermostat determines, based at least in part on the indoor air quality score, a mitigation action, wherein the mitigation action comprises one or more actions selected from the group of: (i) a filtering action comprising filtering air provided to the space using an air purification subsystem, and (ii) a ventilation action comprising ventilating the space using a ventilation subsystem. The mitigation action is executed, or implemented, by adjusting one or more components of the HVAC system.

Abstract: An air quality measuring device that includes a first chamber, a second chamber, a third chamber, and a fourth chamber. The first chamber includes a first inlet configured to receive a first airflow, a first outlet configured to receive a first portion of the first airflow, and a second outlet configured to receive a second portion of the first airflow. The second chamber includes a second inlet configured to receive the first portion of the first airflow and a first sensor disposed within the second chamber. The third chamber includes a third inlet configured to receive the second portion of the first airflow and a second sensor disposed within the third chamber. The fourth chamber includes a fourth inlet configured to receive the second portion of the first airflow and a third sensor disposed within the fourth chamber.

Abstract: A pressure probe includes a tube having an output end, an internal passage, an axial run, and pressure orifices axially aligned along a downstream side of the axial run. The pressure orifices are in communication with the output end through the internal passage and an upstream side of the axial run that is opposite from the downstream side of the axial run and does not include a pressure orifice. The downstream side is perpendicular to airflow.