Thermostat with demand controlled indoor air quality
AssigneeTyco Fire & Security GmbH
InventorsSayan Chakraborty, Aaron D. Wagner
Life of this patent
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Abstract
A HVAC system includes an environmental sensor configured to provide an indoor air quality (IAQ) value indicative of at least one of a pollutant or a pathogen in a space in the building and a controller positioned in the space, the controller configured to receive the IAQ value from the environmental sensor, determine if the IAQ value is above a IAQ setpoint for the space, determine an occupancy status for the space, and control HVAC equipment to ventilate the space with outdoor air at a flowrate in response to determining that the IAQ value is above the IAQ setpoint, such that the flow rate when the occupancy status of the space is unoccupied is less than the flow rate when the occupancy status of the space is occupied.
Claims20
A heating, ventilation, or air conditioning (HVAC) system for a building, the HVAC system comprising:
- an environmental sensor configured to provide an indoor air quality (IAQ) value indicative of a concentration of at least one of a pollutant or a pathogen in a space in the building;
- and
- a controller positioned in the space, the controller comprising a processing circuit comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
- receive the IAQ value from the environmental sensor;
- determine if the IAQ value in the space is above an IAQ setpoint for the space;
- determine an occupancy status for the space;
- calculate a purge duration of a pre-occupancy purge mode or a post-occupancy purge mode based on an air exchange rate of the space and a number of air changes;
- and
- control HVAC equipment to ventilate the space with outdoor air at a flowrate in response to determining that the IAQ value is above the IAQ setpoint, such that the flowrate when the occupancy status of the space is unoccupied is less than the flowrate when the occupancy status of the space is occupied except during execution of the pre-occupancy purge mode or the post-occupancy purge mode.
A method for operating a heating, ventilation, or air conditioning (HVAC) system for a building, the method comprising:
- measuring an indoor air quality (IAQ) value indicative of a concentration of at least one of a pollutant or a pathogen in a space in the building;
- determining if the IAQ value in the space is above a IAQ setpoint for the space;
- determining an occupancy status for the space;
- calculating a purge duration of a pre-occupancy purge mode or a post-occupancy purge mode based on an air exchange rate of the space and a number of air changes;
- and
- controlling HVAC equipment in the HVAC system to ventilate the space with outdoor air at a flowrate in response to determining that the IAQ value is both (i) above the IAQ setpoint and (ii) above an outdoor air quality value by at least a threshold value, such that the flowrate when the occupancy status of the space is unoccupied is less than the flowrate when the occupancy status of the space is occupied except during execution of the pre-occupancy purge mode or the post-occupancy purge mode.
A heating, ventilation, or air conditioning (HVAC) system for a building, the HVAC system comprising:
- an environmental sensor configured to provide an indoor air quality (IAQ) value indicative of a concentration of at least one of a pollutant or a pathogen in a space in the building;
- and
- a controller positioned in the space, the controller comprising a processing circuit comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
- receive the IAQ value from the environmental sensor;
- determine if the IAQ value in the space is above an IAQ setpoint for the space;
- determine an occupancy status for the space during an occupancy period;
- receive a user input indicating the space should be purged based on the occupancy status;
- calculate a purge duration of at least one of a pre-occupancy purge mode or a post-occupancy purge mode based on an air exchange rate of the space and a number of air changes;
- and
- control HVAC equipment to ventilate the space with outdoor air for the purge duration during a pre-occupancy or post-occupancy period in response to determining that the IAQ value is above the IAQ setpoint, such that the HVAC equipment ventilates the space at a flowrate that is less during the occupancy period than during the pre-occupancy or post-occupancy period except during the purge duration of the pre-occupancy purge mode or the post-occupancy purge mode.
Dependencies are inferred from the claim text.