Thermostat with epidemic control ventilation

Abstract

A controller for controlling HVAC equipment in a building includes a processing circuit configured to receive an occupancy schedule indicating at least one of a first occupied period or a last unoccupied period for a space in the building for a schedule period and receive a user input indicating the space should be purged based on occupancy. The controller selects, based on the user input, at least one of a pre-occupancy purge mode or a post-occupancy purge mode. The controller is further configured to control the HVAC equipment to ventilate the space for a purge duration prior to the beginning of the first occupied period in response to selecting a pre-occupancy purge mode, and ventilate the space for the purge duration at the beginning of the last unoccupied period in response to selecting a post-occupancy purge mode.

What is claimed is: 
     
         1 . A controller for controlling heating, ventilation, or air conditioning (HVAC) equipment in a building, 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 a user input indicating a space should be purged and a damper setting and fan setting for a purge duration; 
 providing a carbon dioxide threshold and a purge schedule; and 
 control the HVAC equipment to ventilate the space for a purge in response to a carbon dioxide level being above the carbon dioxide threshold and in response to the purge schedule using the damper setting and the fan setting. 
   
     
     
         2 . The controller of  claim 1 , the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
 in response to selecting a pre-occupancy purge mode, calculate a pre-occupancy purge start time based on the purge duration and an occupancy schedule, wherein the pre-occupancy purge start time is a latest time ventilation can begin and the purge duration elapse before the beginning of a first occupied period;   control the HVAC equipment to ventilate the space for the purge duration starting at the pre-occupancy purge start time prior to the end of a first unoccupied period in response to selecting the pre-occupancy purge mode; and   control the HVAC equipment to ventilate the space for the purge duration starting at the beginning of the last unoccupied period in response to selecting a post-occupancy purge mode.   
     
     
         3 . The controller of  claim 1 , wherein the HVAC equipment comprises an air economizer including a damper configured to control a rate of outdoor airflow into the space, wherein the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to control the HVAC equipment to ventilate the space by modulating the damper. 
     
     
         4 . The controller of  claim 2 , wherein the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to control the HVAC equipment to ventilate the space by driving a damper to a 100% open position for the purge duration before returning the damper to a minimum ventilation position at the end of the purge duration. 
     
     
         5 . The controller of  claim 1 , the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
 receive outdoor air data indicative of at least one of temperature, pressure, or humidity of air outside the building from an outdoor environmental sensor;   determine, based on the outdoor air data, an outdoor air quality of outdoor air; and   control the HVAC equipment to ventilate the space based on an occupancy schedule and the outdoor air quality.   
     
     
         6 . The controller of  claim 2 , the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
 select either a purge mode or a normal mode based on outdoor air quality; and   control the HVAC equipment to ventilate the space based on the occupancy schedule, the outdoor air quality, and the selected mode,   wherein the HVAC equipment provides outdoor air to the space in response to selecting the purge mode, and   wherein the HVAC equipment provides return air to the space in response to selecting the normal mode.   
     
     
         7 . The controller of  claim 2 , the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
 receive occupancy data from an occupant sensor configured to detect a presence of an occupant in the space;   determine, based on the occupancy data, if the space is occupied at the beginning of the last unoccupied period indicated by the occupancy schedule; and   delay, until the occupancy data indicates the space is unoccupied, controlling the HVAC equipment to ventilate the space for the purge duration at the beginning of the last unoccupied period in response to selecting the post-occupancy purge mode.   
     
     
         8 . The controller of  claim 1 , the one or more memory devices are further configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to:
 receive an indoor air quality (IAQ) value indicative of a concentration of at least one of a pollutant or a pathogen in the space in the building;   determine if the IAQ value in the space is above an IAQ setpoint for the space;   determine an occupancy status for the space; and   control the HVAC equipment to ventilate the space with outdoor air at a flow rate 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.   
     
     
         9 . A method for operating a controller for heating, ventilation, or air conditioning (HVAC) equipment in a building, the method comprising:
 receiving an occupancy schedule indicating at least one of a first occupied period or a last unoccupied period for a space in the building for a schedule period;   receiving a user input indicating the space should be purged based on occupancy;   selecting, based on the user input, at least one of a pre-occupancy purge mode or a post-occupancy purge mode; and   controlling the HVAC equipment to ventilate the space for a purge duration prior to the beginning of the first occupied period in response to selecting the pre-occupancy purge mode.   
     
     
         10 . The method of  claim 9 , wherein the controller is communicably coupled to a building management system (BMS), the method further comprising receiving the occupancy schedule from the BMS. 
     
     
         11 . The method of  claim 9 , further comprising:
 in response to selecting the pre-occupancy purge mode, calculating a pre-occupancy purge start time based on the purge duration and the occupancy schedule, wherein the pre-occupancy purge start time is the latest time ventilation can begin and the purge duration elapse before the beginning of the first occupied period;   controlling the HVAC equipment to ventilate the space for the purge duration starting at the pre-occupancy purge start time prior to the end of a first unoccupied period in response to selecting a pre-occupancy purge mode; and   controlling the HVAC equipment to ventilate the space for the purge duration starting at the beginning of the last unoccupied period in response to selecting the post-occupancy purge mode.   
     
     
         12 . The method of  claim 11 , wherein the HVAC equipment comprises an air economizer including a damper configured to control a rate of outdoor airflow into the space, the method further comprising controlling the HVAC equipment to ventilate the space by modulating the damper. 
     
     
         13 . The method of  claim 11 , further comprising controlling the HVAC equipment to ventilate the space by driving a damper to a preset purge damper position for the purge duration before returning the damper to a minimum ventilation position at the end of the purge duration. 
     
     
         14 . The method of  claim 11 , further comprising:
 receiving outdoor air data indicative of at least one of temperature, pressure, or humidity of air outside the building from an outdoor environmental sensor;   determining, based on outdoor air data, an outdoor air quality of outdoor air; and   controlling the HVAC equipment to ventilate the space based on the occupancy schedule and the outdoor air quality.   
     
     
         15 . The method of  claim 9 , further comprising:
 selecting either a purge mode or a normal mode based on outdoor air quality; and   controlling the HVAC equipment to ventilate the space based on the occupancy schedule, the outdoor air quality, and the selected mode,   wherein the HVAC equipment provides outdoor air to the space in response to selecting the purge mode, and   wherein the HVAC equipment provides return air to the space in response to selecting the normal mode.   
     
     
         16 . The method of  claim 11 , further comprising controlling the HVAC equipment to ventilate the space by driving a damper to a purge position for the purge duration before returning the damper to a minimum ventilation position at the end of the purge duration, wherein the purge position is based on at least one of a temperature of the space in the building a temperature of outdoor air used to ventilate the space. 
     
     
         17 . The method of  claim 11 , further comprising:
 receiving occupancy data from an occupant sensor configured to detect a presence of an occupant in the space;   determining, based on occupancy data, if the space is occupied at the beginning of the last unoccupied period indicated by the occupancy schedule; and   delaying, until the occupancy data indicates the space is unoccupied, controlling the HVAC equipment to ventilate the space for the purge duration at the beginning of the last unoccupied period in response to selecting the post-occupancy purge mode.   
     
     
         18 . The method of  claim 11 , further comprising:
 measuring an indoor air quality (IAQ) value indicative of a concentration of at least one of a pollutant or a pathogen in the 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; and   controlling HVAC equipment to ventilate the space with outdoor air at a flow rate 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.   
     
     
         19 . A controller for controlling ventilation equipment in a building, 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 a user input indicating a space should be purged and a damper setting or fan setting for a purge duration;   provide a carbon dioxide threshold and a purge schedule; and   control the equipment to ventilate the space for a purge in response to a carbon dioxide level being above the carbon dioxide threshold and in response to the purge schedule using the damper setting or the fan setting.   
     
     
         20 . The controller of  claim 19 , wherein the purge schedule using the damper setting or the fan setting for a pre-purge mode and a post-occupancy purge mode.