PRECONDITIONING CONTROLS AND METHODS FOR AN ENVIRONMENTAL CONTROL SYSTEM

• US 20140129034A1
• Filed: 01/14/2014
• Published: 05/08/2014
• Est. Priority Date: 09/30/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Nest Labs Incorporated (Alphabet Inc.)
• Inventors: Matsuoka, Yoky, Stefanski, Mark
• Granted Patent: US 9,470,430 B2
• Time in Patent Office: Days
• US Class Current: 700/278
• 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 11/52 Indication arrangements, e.g. displays
• CPC Class Codes: F24F 11/523 for displaying temperature data
• CPC Class Codes: F24F 11/58 using Internet communication
• CPC Class Codes: F24F 11/61 using timers
• 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 11/65 for selecting an operating mode
• CPC Class Codes: F24F 11/66 Sleep mode
• CPC Class Codes: F24F 11/88 Electrical aspects, e.g. circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2110/12 of the outside air
• CPC Class Codes: F24F 2120/00 Control inputs relating to users or occupants
• CPC Class Codes: G05B 19/0428 Safety, monitoring G05B19/0423 takes precedence
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control
• CPC Class Codes: G05D 23/1904 variable in time
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G06F 1/3293 by switching to a less power-consuming processor, e.g. sub-CPU
• CPC Class Codes: H05B 1/028 Airconditioning
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Embodiments of the invention describe thermostats that are configured to precondition an enclosure and methods for performing the same. According to one embodiment, a method of preconditioning an enclosure includes providing a thermostat and computing a set of preconditioning criteria information (PCI) with said thermostat. The computed PCI is typically representative of time and ambient temperature conditions for which preconditioning should be performed. The PCI may be stored in memory and used to compare against a current time and current ambient temperature condition of the enclosure to determine whether to enter the thermostat into a preconditioning state. If a determination is made that the PCI criteria are satisfied, the thermostat may be entered into the preconditioning state to heat or cool the enclosure. One or more of these processes may be performed while a processor of the thermostat is in a relatively high power mode or relatively low power mode.

Claims

1. An HVAC control device comprising:

a processing system that receives ambient temperature information for an enclosure and information from an HVAC schedule, the HVAC schedule including a first setpoint characterized by a first setpoint temperature and a first setpoint time, the HVAC schedule including a second setpoint characterized by a second setpoint temperature and a second setpoint time, the first setpoint time and second setpoint time defining a first time interval therebetween, said processing system being configured to control the HVAC system to precondition the enclosure during at least a part of said first time interval such that the ambient temperature reaches substantially said second setpoint temperature by said second setpoint time, wherein the processing system controls the HVAC system to precondition the enclosure by;

processing the second setpoint temperature in conjunction with first information derived from a historical record of previous heating and cooling cycles for said HVAC system as controlled by the HVAC control device to compute a set of preconditioning criteria information (PCI) representative of time and ambient temperature conditions for which the preconditioning should be performed;

during said time interval, comparing a current time and current ambient temperature against said PCI to determine whether to enter into a preconditioning state; and

when it is so determined, entering into said preconditioning state upon a determination that the PCI criteria are satisfied.

2. The HVAC control device of claim 1, wherein the set of PCI is computed based on a time to temperature for the enclosure that defines a change in temperature response for the enclosure when subjected to a heating or cooling operation.

3. The HVAC control device of claim 2, wherein the time to temperature for the enclosure is adjusted for a subsequent preconditioning operation based on a response of the enclosure to said preconditioning, said response being included in said historical record of said previous heating and cooling cycles.

4. The HVAC control device of claim 1, wherein the processing system comprises:

a first processor characterized by at least a relatively high electrical power-consuming first mode of operation and a relatively low electrical power-consuming second mode of operation, wherein said processing is performed by said first processor; and

a second processor characterized by a relatively low electrical power-consuming mode of operation, wherein said comparing is performed by said second processor.

5. The HVAC control device of claim 4, wherein said set of PCI is computed via said first processor, and wherein said set of PCI is communicated to said second processor for comparing said current time and current ambient temperature against said PCI.

6. The HVAC control device of claim 5, wherein communicating said set of PCI to said second processor comprises communicating a partial set of said set of PCI, said partial set covering a time interval extending to either of:

1) an anticipated or requested time of said first processor entering into said first mode of operation, and

     2) said second setpoint time.

7. The HVAC control device of claim 4, wherein comparing said current time and current ambient temperature against said PCI to determine whether to enter into said preconditioning state comprises:

determining an amount of time relative to said first processor entering into said second mode of operation;

determining an ambient temperature condition of said PCI associated with said amount of time, the ambient temperature condition representing a temperature for which preconditioning should be performed; and

comparing said current ambient temperature with said ambient temperature condition to determine whether said PCI criteria are satisfied.

8. The HVAC control device of claim 4, wherein processing said second setpoint temperature in conjunction with said first information to compute said set of PCI comprises:

determining a first time duration defined by said second setpoint time and a first time within said first time interval;

deriving from said historical record, a first ambient temperature condition associated with said first time duration that represents a temperature for which preconditioning should be performed;

determining a second time duration defined by said first time and a second time within said first time interval;

deriving from said historical record, a second ambient temperature condition associated with said second time duration that represents an additional temperature for which preconditioning should be performed; and

determining at least one addition time duration within said first time interval; and

deriving at least one additional ambient temperature condition representative of at least one additional temperature for which preconditioning should be performed.

9. The HVAC control device of claim 1, wherein said set of PCI comprises either or both an upper range representative of conditions for which preconditioning cooling should be performed and a lower range representative of conditions for which preconditioning heating should be performed.

10. The HVAC control device of claim 1, wherein said set of PCI comprise a step function, and wherein preconditioning is limited to a defined duration.

11. A method comprising:

providing an HVAC control device comprising;

a processing system that receives ambient temperature information for an enclosure and information from an HVAC schedule, the HVAC schedule including a first setpoint characterized by a first setpoint temperature and a first setpoint time, the HVAC schedule including a second setpoint characterized by a second setpoint temperature and a second setpoint time, the first setpoint time and second setpoint time defining a first time interval therebetween, said processing system being configured to control the HVAC system to precondition the enclosure during at least a part of said first time interval such that the ambient temperature reaches substantially said second setpoint temperature by said second setpoint time;

processing the second setpoint temperature in conjunction with first information derived from a historical record stored of previous heating and cooling cycles for said HVAC system as controlled by said HVAC control device to compute a set of preconditioning criteria information (PCI) representative of time and ambient temperature conditions for which the preconditioning should be performed;

during said time interval, comparing a current time and current ambient temperature against said PCI to determine whether to enter said HVAC control device into a preconditioning state; and

entering said HVAC control device into said preconditioning state upon a determination that the PCI criteria are satisfied.

12. The method of claim 11, wherein said set of PCI is computed based on a time to temperature for said enclosure.

13. The method of claim 12, wherein said time to temperature is adjusted for a subsequent preconditioning operation based on a response of said enclosure to said preconditioning.

14. The method of claim 11, wherein said processing system comprises:

a first processor characterized by at least a relatively high electrical power-consuming first mode of operation and a relatively low electrical power-consuming second mode of operation, wherein said processing is performed by said first processor; and

a second processor characterized by a relatively low electrical power-consuming mode of operation, wherein said comparing is performed by said second processor.

15. The method of claim 14, wherein comparing said current time and current ambient temperature against said set of PCI to determine whether to enter into said preconditioning state comprises:

determining an amount of time relative to said first processor entering into said second mode of operation;

determining an ambient temperature condition of said set of PCI associated with said amount of time, said ambient temperature condition representing a temperature for which preconditioning should be performed; and

comparing said current ambient temperature with said ambient temperature condition to determine whether said set of PCI criteria are satisfied.

16. The method of claim 14, wherein said set of PCI comprises a step function within said first interval of time.

17. The method of claim 16, wherein said set of PCI comprises either or both an upper step function representative of conditions for which preconditioning cooling should be performed and a lower step function representative of conditions for which preconditioning heating should be performed.

18. The method of claim 11, wherein preconditioning is limited to being performed up to one hour prior to the second setpoint time.

19. An HVAC control device comprising:

a processing system that receives ambient temperature information of an enclosure and information from an HVAC schedule, the HVAC schedule including a first setpoint characterized by a first setpoint temperature and a first setpoint time, the HVAC schedule including a second setpoint characterized by a second setpoint temperature and a second setpoint time, the first setpoint time and second setpoint time defining a first time interval therebetween, the processing system being configured to control the HVAC system to precondition the enclosure during at least a part of the first time interval such that the ambient temperature reaches substantially the second setpoint temperature by the second setpoint time, the processing system including a first relatively high power processor and a second relatively low power processor, wherein the processing system controls the HVAC system to preconditioning the enclosure by;

processing, via the first processor, the second setpoint temperature in conjunction with first information derived from a historical record of previous heating and cooling cycles for the HVAC system as controlled by the HVAC control device to compute a set of preconditioning criteria information (PCI) representative of time and ambient temperature conditions for which the preconditioning should be performed;

communicating the set of PCI to the second processor;

comparing, via the second processor, a current time and current ambient temperature against the set of PCI to determine whether to enter into a preconditioning state; and

entering the HVAC control device into the preconditioning state upon a determination that the PCI criteria are satisfied.

20. The HVAC control device of claim 19, wherein the set of PCI is computed based on a time to temperature for the enclosure that defines a change in temperature in a defined amount of time for the enclosure when subjected to a heating or cooling operation.

21. The HVAC control device of claim 19, wherein comparing the current time and current ambient temperature against the set of PCI comprises:

determining, via the second processor, an ambient temperature condition representing a temperature for which preconditioning should be performed; and

comparing, via the second processor, the current ambient temperature with the ambient temperature condition to determine whether the set of PCI criteria are satisfied.

22. The HVAC control device of claim 19, wherein processing the second setpoint temperature in conjunction with the first information to compute the set of PCI comprises:

calculating a step function having a plurality of time durations and a plurality of ambient temperature conditions, wherein each time duration is associated with a respective ambient temperature condition, and wherein the step function is calculated by;

determining the plurality of time durations, wherein each time duration is defined by a first time and a second time within the first time interval and measured relative to the second setpoint time; and

deriving from the historical record and for each time duration, an ambient temperature condition that represents a temperature for which preconditioning should be performed.

23. The HVAC control device of claim 19, wherein the set of PCI comprises either or both an upper range representative of conditions for which preconditioning cooling should be performed and a lower range representative of conditions for which preconditioning heating should be performed.

24. A method comprising:

providing an HVAC control device comprising;

a processing system that receives ambient temperature information for an enclosure and information from an HVAC schedule for the enclosure, the HVAC schedule including a first setpoint characterized by a first setpoint temperature and a first setpoint time, the HVAC schedule including a second setpoint characterized by a second setpoint temperature and a second setpoint time, the first setpoint time and second setpoint time defining a first time interval therebetween, the processing system being configured to control the HVAC system to precondition the enclosure during at least a part of said first time interval such that the ambient temperature reaches substantially the second setpoint temperature by the second setpoint time, the processing system including a first relatively high power processor and a second relatively low power processor;

processing, via the first processor, the second setpoint temperature in conjunction with first information derived from a historical record of previous heating and cooling cycles for the HVAC system as controlled by the HVAC control device to compute a set of preconditioning criteria information (PCI) representative of time and ambient temperature conditions for which the preconditioning should be performed;

communicating the set of PCI to the second processor;

comparing, via the second processor, a current time and current ambient temperature against the set of PCI to determine whether to enter the HVAC control device into a preconditioning state; and

entering the HVAC control device into the preconditioning state upon a determination that the PCI criteria are satisfied.

25. The method of claim 24, wherein the set of PCI is computed based on a time to temperature for the enclosure.

26. The method of claim 25, wherein the time to temperature is adjusted for a subsequent preconditioning operation based on a response of the enclosure to the preconditioning.

27. The method of claim 24, wherein the set of PCI comprises a step function within the first interval of time.

28. The method of claim 27, wherein the set of PCI comprises either or both an upper step function representative of conditions for which preconditioning cooling should be performed and a lower step function representative of conditions for which preconditioning heating should be performed.