Indoor volatile organic compound quantity control systems

Abstract

A heating, ventilation and air conditioning (HVAC) unit can flow conditioned air into an indoor space through a first flow pathway, and receive returned air from the indoor space through a second flow pathway. A sensor module is positioned in the second flow pathway to receive the return air from the indoor space and determine that a quantity of volatile organic compounds (VOCs) in the return air exceeds a threshold VOC quantity. In response, the HVAC unit can flow a quantity of the return air out of the second flow pathway and into the atmosphere, and draw, into the second flow pathway, an equal quantity of air from the atmosphere. The HVAC unit can flow a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space.

1 . A method comprising:
 flowing conditioned air into an indoor space through a first flow pathway;   receiving return air from the indoor space through a second flow pathway fluidically coupled to and separate from the first flow pathway;   flowing the return air through a sensor module positioned in the second flow pathway;   determining, by the sensor module, that a quantity of volatile organic compounds (VOCs) in the return air exceeds a threshold VOC quantity; and   in response to determining, by the sensor module, that the quantity of VOCs in the return air exceeds the threshold VOC quantity:
 flowing, out of the second flow pathway and into the atmosphere, a quantity of the return air, 
 drawing, into the second flow pathway, a quantity of air from the atmosphere equal to the quantity of the return air that was flowed into the atmosphere, and 
 flowing a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space. 
   
     
     
         2 . The method of  claim 1 , wherein, flowing, out of the second flow pathway and into the atmosphere, a quantity of the return air, comprises opening a first damper positioned in the second flow pathway upstream of a first outlet to the atmosphere. 
     
     
         3 . The method of  claim 2 , wherein opening the first damper comprises transmitting, by the sensor module and to a first damper controller operatively coupled to the first damper, a signal to open the first damper in response to determining, by the sensor module, that the quantity of VOCs in the return air exceeds the threshold quantity. 
     
     
         4 . The method of  claim 3 , wherein the sensor module comprises a VOC sensor and a damper actuator operatively coupled to the VOC sensor, wherein transmitting, by the sensor module and to the first damper controller, the instruction to open the first damper comprises transmitting, by the damper actuator, the instruction to the first damper controller. 
     
     
         5 . The method of  claim 1 , wherein, drawing, into the second flow pathway, a quantity of air from the atmosphere equal to the quantity of the return air that was flowed into the atmosphere comprises opening a second damper positioned in the second flow pathway upstream of a second outlet to the atmosphere. 
     
     
         6 . The method of  claim 5 , wherein opening the second damper comprises transmitting, by the sensor module and to a second damper controller operatively coupled to the second damper, a signal to open the second damper in response to determining, by the sensor module, that the quantity of VOCs in the return air exceeds the threshold quantity. 
     
     
         7 . The method of  claim 6 , wherein the sensor module comprises a VOC sensor and a damper actuator operatively coupled to the VOC sensor, wherein transmitting, by the sensor module and to the second damper controller, the instruction to open the second damper comprises transmitting, by the damper actuator, the instruction to the second damper controller. 
     
     
         8 . The method of  claim 1 , wherein the quantity of the return air flowed into the atmosphere in response to determining that the quantity of VOCs in the return air exceeds the threshold VOC quantity is a first quantity of the return air, wherein the method further comprises:
 determining, by the sensor module, that the quantity of VOCs in the return air does not exceed the threshold VOC quantity;   in response to determining, by the sensor module, that the quantity of VOCs in the return air does not exceed the threshold VOC quantity:
 flowing, out of the second flow pathway and into the atmosphere, a second quantity of the return air less than the first quantity of the return air, 
 drawing, into the second flow pathway, a quantity of air from the atmosphere equal to the second quantity of the return air, and 
 flowing a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space. 
   
     
     
         9 . A system comprising:
 a heating, ventilation and air conditioning (HVAC) unit configured to:
 flow conditioned air into an indoor space through a first flow pathway; and 
 receiving return air from the indoor space through a second flow pathway fluidically coupled to and separate from the first flow pathway; and 
   a sensor module positioned in and fluidically coupled to the second flow pathway, the sensor module configured to:
 receive the return air from the indoor space; and 
 determine that a quantity of volatile organic compounds (VOCs) in the return air exceeds a threshold VOC quantity, 
 wherein, in response to the sensor module determining that the quantity of VOCs in the return air exceeds the threshold VOC quantity, the HVAC unit is configured to
 flow, out of the second flow pathway and into the atmosphere, a quantity of the return air, 
 draw, into the second flow pathway, a quantity of air from the atmosphere equal to the quantity of the return air that was flowed into the atmosphere, and 
 flow a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space. 
 
   
     
     
         10 . The system of  claim 9 , wherein the system comprises a first damper positioned in the second flow pathway upstream of a first outlet to the atmosphere, wherein the first damper is configured to open to permit the quantity of the return air to flow out of the second flow pathway and into the atmosphere. 
     
     
         11 . The system of  claim 10 , wherein the system comprises a first damper controller operatively coupled to the sensor module, wherein the sensor module is configured to transmit a signal to the first damper controller to open the first damper, and wherein the first damper controller is configured to open the first damper in response to receiving the signal from the sensor module. 
     
     
         12 . The system of  claim 11 , wherein the sensor module comprises a VOC sensor and a damper actuator operatively coupled to the VOC sensor, wherein the damper actuator transmits the instruction to the first damper controller. 
     
     
         13 . The system of  claim 9 , wherein the system comprises a second damper positioned in the second flow pathway upstream of a second outlet to the atmosphere, wherein the second damper is configured to open to draw the quantity of the air equal to the quantity of the return air that was flowed into the atmosphere. 
     
     
         14 . The system of  claim 13 , wherein the system comprises a second damper controller operatively coupled to the sensor module, wherein the sensor module is configured to transmit a signal to the second damper controller to open the second damper, and wherein the second damper controller is configured to open the second damper in response to receiving the signal from the sensor module. 
     
     
         15 . The system of  claim 14 , wherein the sensor module comprises a VOC sensor and a damper actuator operatively coupled to the VOC sensor, wherein the damper actuator transmits the instruction to the second damper controller. 
     
     
         16 . The system of  claim 9 , wherein the quantity of the return air flowed into the atmosphere in response to determining that the quantity of VOCs in the return air exceeds the threshold VOC quantity is a first quantity of the return air, wherein the sensor module is configured to determine that the quantity of VOCs in the return air does not exceed the threshold VOC quantity,
 wherein, in response to the sensor module determining that the quantity of VOCs in the return air does not exceed the threshold VOC quantity, the HVAC unit is configured to:
 flow, out of the second flow pathway and into the atmosphere, a second quantity of the return air less than the first quantity of the return air, 
 draw, into the second flow pathway, a quantity of air from the atmosphere equal to the second quantity of the return air, and 
 flow a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space. 
   
     
     
         17 . A non-transitory computer-readable medium storing instructions executable by one or more computer systems to perform operations comprising:
 receiving a first signal representing a first quantity of volatile organic compounds (VOCs) in return air received from an indoor space into which conditioned air was flowed;   determining that the first quantity of VOCs in the return air does not exceed a threshold VOC quantity;   in response to determining that the first quantity of VOCs in the return air does not exceed the threshold VOC quantity:
 transmitting instructions to open a first damper to flow a first quantity of the return air into the atmosphere, and 
 transmitting instructions to open a second damper to draw a first quantity of air from the atmosphere equal to the first quantity of the return air flowed into the atmosphere, wherein the first quantity of the air from the atmosphere mixes with a remainder of the return air received from the indoor space, is conditioned and is flowed back into the indoor space; 
   after receiving the first signal, receiving a second signal representing a second quantity of the VOCs in the return air received from the indoor space;   determining that the second quantity of VOCs in the return air exceeds the threshold VOC quantity; and   in response to determining that the second quantity of VOCs in the return air exceeds the threshold VOC quantity:
 transmitting instructions to open a first damper to flow a second quantity of the return air into the atmosphere, wherein the second quantity of the return air is greater than the first quantity of the return air flowed into the atmosphere in response to receiving the first signal, and 
 transmitting instructions to open a second damper to draw a second quantity of air from the atmosphere equal to the second quantity of the return air flowed into the atmosphere, wherein the second quantity of the air from the atmosphere mixes with the remainder of the return air received from the indoor space, is conditioned and is flowed back into the indoor space. 
   
     
     
         18 . The medium of  claim 17 , wherein in response to determining that the first quantity of VOCs in the return air exceeds the threshold VOC quantity, transmitting instructions to open the first damper to flow the second quantity of the return air into the atmosphere comprises:
 determining a flow rate of the return air received from the indoor space; and   determining, based on the flow rate of the return air, a duration for which the first damper is to remain open to allow the second quantity of the return air to flow into the atmosphere,   wherein transmitting the instructions to open the first damper to flow the second quantity of the return air into the atmosphere comprises:
 opening the first damper for the determined duration, and 
 closing the first damper after the determined duration. 
   
     
     
         19 . The medium of  claim 17 , wherein in response to determining that the first quantity of VOCs in the return air exceeds the threshold VOC quantity, transmitting instructions to open the second damper to draw the second quantity of the air from the atmosphere comprises:
 determining a flow rate of the return air received from the indoor space; and   determining, based on the flow rate of the return air:
 a flow rate at which the second quantity of air is to be drawn from the atmosphere, and 
 a duration for which the second damper is to remain open to allow the second quantity of air to be drawn from the atmosphere, 
   wherein transmitting the instructions to open the second damper to draw the second quantity of air from the atmosphere comprises:
 opening the second damper for the determined duration, 
 drawing air from the atmosphere for the determined duration and at the determined flow rate at which the second quantity of air is to be drawn from the atmosphere, and 
 closing the second damper after the determined duration. 
   
     
     
         20 . The medium of  claim 17 , wherein the instructions to open the first damper to flow the second quantity of the return air into the atmosphere and the instructions to open the second damper to draw the second quantity of air from the atmosphere equal to the second quantity of the return air flowed into the atmosphere are transmitted simultaneously.