Method and system for human presence correlation using carbon dioxide

Patent metadata

Field	Value
Publication number	US-10145831-B2
Application number	US-201615293665-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Mar 14, 2013
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

Method and system for detecting and/or quantifying recent human presence in an environment using a calculated rate of decay of carbon dioxide concentration levels within that environment. A sensor measures the change in carbon dioxide levels over time to calculate the rate of decay to equilibrium and extrapolate recent human presence. Also provided is a method and system for quantifying recent human activity in an environment using the calculated rate of decay to equilibrium.

First claim

What is claimed is:

1. A method for detecting recent human presence in a space, the method comprising the steps of:
measuring, using a carbon dioxide sensor, the concentration of carbon dioxide within the space to obtain a first carbon dioxide measurement;
measuring, using a carbon dioxide sensor, the concentration of carbon dioxide within the space after a first period of time elapses to obtain at least a second carbon dioxide measurement;
calculating the carbon dioxide rate of decay using at least the first and second carbon dioxide measurements;
extrapolating, using the calculated rate of decay, the time at which the concentration of carbon dioxide in the space was approximately equivalent to a carbon dioxide concentration of interest; and
correlating the carbon dioxide rate of decay to a level of human presence in the space at the extrapolated time.

2. The method of claim 1 , wherein the space is a room.

3. The method of claim 1 , wherein the carbon dioxide concentration of interest is predetermined by a user.

4. The method of claim 1 , wherein the carbon dioxide sensor is an infrared gas sensor.

5. The method of claim 1 , wherein the carbon dioxide sensor is a chemical gas sensor.

6. The method of claim 1 , further comprising the step of estimating, based on the calculated rate of decay, a number of occupants of the space at the extrapolated time.

7. The method of claim 1 , further comprising the step of receiving, from a user, an estimate of a number of occupants of the space at the extrapolated time, and further wherein said correlating step is based at least in part on the received number of occupants.

8. A system for detecting recent human presence in a space, the system comprising:
a sensor configured to measure the concentration of carbon dioxide within the space to obtain a first carbon dioxide measurement and configured to measure the concentration of carbon dioxide within the space after a first period of time elapses to obtain at least a second carbon dioxide measurement; and
a processor configured to: (i) calculate the carbon dioxide rate of decay using at least the first and second carbon dioxide measurements; (ii) extrapolate, using the calculated rate of decay, the time at which the concentration of carbon dioxide in the space was approximately equivalent to a carbon dioxide concentration of interest; and (iii) correlate the carbon dioxide rate of decay to a level of human presence in the space at the extrapolated time.

9. The system of claim 8 , wherein the sensor is an infrared gas sensor.

10. The system of claim 8 , wherein the carbon dioxide sensor is a chemical gas sensor.

11. The system of claim 8 , wherein the carbon dioxide concentration of interest is predetermined by a user.

12. The system of claim 8 , further comprising a user interface.

13. The system of claim 8 , wherein the processor is further configured to estimate, based on the calculated rate of decay, a number of occupants of the space at the extrapolated time.

14. The system of claim 8 , wherein the processor is further configured to receive an estimate of a number of occupants of the space at the extrapolated time, and further wherein said correlation is based at least in part on the received number of occupants.

15. A computer program stored on a computer useable storage medium, the computer program configured to implement a method for detecting recent human presence in a space, the method comprising the steps of:
receiving, from a sensor, the concentration of carbon dioxide within the space to obtain a first carbon dioxide measurement;
receiving, from a sensor, the concentration of carbon dioxide within the space after a first period of time elapses to obtain at least a second carbon dioxide measurement;
calculating the carbon dioxide rate of decay using at least the first and second carbon dioxide measurements;
extrapolating, using the calculated rate of decay, the time at which the concentration of carbon dioxide in the space was approximately equivalent to a carbon dioxide concentration of interest; and
correlating the carbon dioxide rate of decay to a level of human presence in the space at the extrapolated time.

16. The computer program of claim 15 , wherein said space is a room.

17. The computer program of claim 15 , wherein said carbon dioxide concentration of interest is determined by a user.

18. The computer program of claim 15 , wherein the sensor is an infrared gas sensor.

19. The computer program of claim 15 , wherein the carbon dioxide sensor is a chemical gas sensor.

20. The computer program of claim 15 , further comprising the step of estimating, based on the calculated rate of decay, a number of occupants of the space at the extrapolated time.

Assignees

• Src Inc

Inventors

• Angeli Mark
• Durst John
• Liddil Garrett
• Distasio Marcello M

Classifications

• G01N33/0067 Primary

  by measuring the rate of variation of the concentration · CPC title

• G01V11/002

  Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant (means for transmitting well survey signals E21B47/12; signal transmission systems in general G08C; transmission in general H04B) · CPC title

• G01N2033/0068

  Physics · mapped topic

• G01N33/004

  CO or CO2 · CPC title

• Y02A50/20

  Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters · CPC title