Thermodynamic modeling for enclosures

• US 8,606,374 B2
• Filed: 09/14/2010
• Issued: 12/10/2013
• Est. Priority Date: 09/14/2010
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Nest Labs Incorporated (Alphabet Inc.)
• Inventors: Fadell, Anthony Michael, Rogers, Matthew Lee, Rogers, Kipp Avery, Ishihara, Abraham K., Ben-Menahem, Shahar, Sharan, Rangoli
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): LAUGHLIN, NATHAN L
• Application Number:
  US12/881,463
• Publication Number:
  US 20120065783A1
• Time in Patent Office: 1,183 Days
• Field of Search: 700 29- 31, 700276-278, 700299-300
• US Class Current: 700/31
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/64 using pre-stored data
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2110/20 Humidity
• CPC Class Codes: F24F 2130/00 Control inputs relating to environmental factors not covered by group F24F2110/00
• CPC Class Codes: F24F 2130/10 Weather information or forecasts
• CPC Class Codes: G05B 13/048 using a predictor
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G06F 2113/14 Pipes
• CPC Class Codes: G06F 30/13 Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

Systems and methods for modeling the behavior of an enclosure for use by a control system of an HVAC system are described. A model for the enclosure that describes the behavior of the enclosure for use by the control system is updated based on a weather forecast data. The weather forecast data can include predictions more than 24 hours in the future, and can include predictions such as temperature, humidity and/or dew point, solar output, precipitation. The model for the enclosure can also be updated based on additional information and data such as historical weather data such as temperature, humidity, wind, solar output and precipitation, occupancy data, such as predicted and/or detected occupancy data, calendar data, and data from the one or more weather condition sensors that sense current parameters such as temperature, humidity, wind, precipitation, and/or solar output. The model for the enclosure can be updated based also on an enclosure model stored in a database, and/or on enclosure information from a user. The model can be updated based on active testing of the enclosure which can be performed automatically or in response to user input. The testing can include heating and/or cooling the enclosure at times when the enclosure is not likely to be occupied.

Claims

1. A method for modeling internal environmental behavior of an enclosure for use by a control system of an HVAC system installed in the enclosure comprising:

creating, over time, an occupancy model of the enclosure capable of predicting when there will be no occupants in the enclosure;

determining an error in a current environmental model for the enclosure, wherein the current environmental model describes behavior of the enclosure for use by the control system, by comparing (i) predicted HVAC system performance according the current environmental model, with (ii) actual HVAC system performance; and

updating the current environmental model, if the error exceeds a particular threshold, by;

predicting, from the occupancy model, a period of time when there will be no occupants in the enclosure;

accessing a weather forecast corresponding to the period of time; and

determining if an exterior temperature according to the accessed weather forecast is within a particular range, and if so;

actively inducing, during the period of time, a change in an internal environment of the enclosure;

measuring a response of the internal environment of the enclosure at least in part due to the induced change; and

updating with a processing system the current environmental model, the updating being based at least in part on the measurement of the response from the induced change.

2. A method according to claim 1 wherein the change is actively induced for purposes of updating the current environmental model for the enclosure.

3. A method according to claim 1 where the measured response of the internal environment of the enclosure is further based in part on exterior environmental conditions.

4. A method according to claim 1 wherein the induced change and the response are monitored by an excitation monitor that determines if the change and/or response is adequate to generate an updated environmental model for the enclosure.

5. A method according to claim 1 wherein the change is actively induced in response to input by a user.

6. A method according to claim 1 wherein the change is actively induced automatically by the processing system.

7. A method according to claim 6 wherein the change is actively induced due in part to a change of season.

8. A method according to claim 6 wherein the change is actively induced based at least in part on the type of enclosure.

9. A method according to claim 6 wherein the change is actively induced based at least in part on a difference between measurements made within the enclosure and values predicted by the current environmental model.

10. A method according to claim 6 wherein the processing system determines if the change will be actively induced based at least in part on a cost function.

11. A method according to claim 1 wherein the induced change is heating within at least a portion of the enclosure using the HVAC system.

12. A method according to claim 1 wherein the induced change is cooling within at least a portion of the enclosure using the HVAC system.

13. A method according to claim 1 wherein the induced change is changing the humidity within at least a portion of the enclosure.

14. A method according to claim 1 wherein the enclosure is a dwelling.

15. A system for modeling internal environmental behavior of an enclosure for use by a control system of an HVAC system installed in the enclosure comprising:

a processor; and

a non-transitory storage medium haying instructions stored thereon, the instructions executable by the processor to;

create, over time, an occupancy model of the enclosure capable of predicting when there will be no occupants in the enclosure;

determine an error in a current environmental model for the enclosure, wherein the current environmental model describes behavior of the enclosure for use by the control system, by comparing (i) predicted HVAC system performance according the current environmental model, with (ii) actual HVAC system performance; and

update the current environmental model, if the error exceeds a particular threshold, by;

predicting, from the occupancy model, a period of time when there will be no occupants in the enclosure;

accessing a weather forecast corresponding to the period of time; and

determining if an exterior temperature according to the accessed weather forecast is within a particular range, and if so;

actively inducing, during the period of time, a change in the internal environment;

measuring a response of the internal environment of the enclosure at least in part due to the induced change; and

updating the current environmental model for the enclosure based at least in part on the measurement of the response from the induced change.

16. A system according to claim 15 where the measured response of the internal environment of the enclosure is further based in part on exterior environmental conditions.

17. A system according to claim 15 wherein the instructions are further executable by the processor to monitor the induced change and the response and determine if the change and/or response is adequate to generate an updated environmental model for the enclosure.

18. A system according to claim 15 wherein the change is actively induced in response to input by a user.

19. A system according to claim 15 wherein the change is actively induced automatically by the processor.

20. A system according to claim 19 wherein the change is actively induced due in part to a change of season.

21. A system according to claim 19 wherein the change is actively induced based at least in part on the type of enclosure.

22. A system according to claim 19 wherein the change is actively induced based at least in part on a difference between measurements made within the enclosure and values predicted by the current environmental model.

23. A system according to claim 19 wherein the processing system determines if the change will be actively induced based at least in part on a cost function.

24. A system according to claim 15 wherein the induced change is heating within at least a portion of the enclosure.

25. A system according to claim 15 wherein the induced change is cooling within at least a portion of the enclosure.

26. A system according to claim 15 wherein the enclosure is a dwelling.

27. A system according to claim 15 wherein the processing system forms part of the control system of the HVAC system.