Automated adjustment of an HVAC schedule for resource conservation

• US 9,298,197 B2
• Filed: 04/19/2013
• Issued: 03/29/2016
• Est. Priority Date: 04/19/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Matsuoka, Yoky, Malhotra, Mark, Fisher, Evan J.
• Primary Examiner(s): PATEL, RAMESH B
• Application Number:
  US13/866,578
• Publication Number:
  US 20140316584A1
• Time in Patent Office: 1,075 Days
• US Class Current: 1/1
• 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 11/526 giving audible indications
• 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 11/63 Electronic processing
• 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 2110/00 Control inputs relating to air properties
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2120/20 Feedback from users
• CPC Class Codes: F24F 2140/60 Energy consumption
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05D 23/1917 using digital means

Abstract

Apparatus, systems, methods, and related computer program products for optimizing a schedule of setpoint temperatures used in the control of an HVAC system. The systems disclosed include an energy management system in operation with an intelligent, network-connected thermostat located at a structure. The thermostat includes a schedule of setpoint temperatures that is used to control an HVAC system associated with a structure in which the thermostat is located. The schedule of setpoint temperatures is continually adjusted by small, unnoticeable amounts so that the schedule migrates from the original schedule to an optimal schedule. The optimal schedule may be optimal in terms of energy consumption or some other terms.

Claims

1. A method of optimizing energy consumption of a heating, ventilation, and air conditioning (HVAC) system, comprising:

identifying a schedule of temperature setpoints, the schedule of temperature setpoints defining a number of temperature setpoints over a time period;

beginning with the schedule, for each of a succession of periodic time intervals that are each relatively short in comparison to an overall optimization time period, generating an incrementally adjusted version of the schedule as part of an automated schedule adjustment process executed by a thermostat, the incremental change being directed to a setpoint temperature of the number of temperature setpoints and causing less energy usage during one of the periodic time intervals as compared to a previous one of the periodic time intervals, wherein causing less energy usage comprises having a heating system of the HVAC system or an air conditioner of the HVAC system activated less than if the identified schedule was used for controlling the HVAC system; and

for each of the succession of periodic time intervals, controlling the HVAC system according to the incrementally adjusted version of the schedule generated for the periodic time interval.

2. The method of claim 1, further comprising:

identifying a subset of temperature setpoints within the schedule of temperature setpoints, the subset of temperature setpoints corresponding to a sub-interval of the time period over which the schedule of temperature setpoints is defined, wherein generating an incrementally adjusted version of the schedule includes adjusting the subset of temperature setpoints differently than temperature setpoints other than those in the subset.

3. The method of claim 2, further comprising:

generating an occupancy probability profile that indicates a probability that a structure associated with the HVAC system will be occupied at various time; and

determining time boundaries of the sub-interval based on the occupancy probability profile.

4. The method of claim 1, further comprising:

receiving, during one of the periodic time intervals, a user selection of a current temperature setpoint that is different than a corresponding temperature setpoint of the incrementally adjusted version of the schedule generated for the periodic time interval; and

controlling the HVAC system, for at least a certain time period within the one of the period time intervals, according to the user selected current temperature setpoint rather than the corresponding temperature setpoint of the incrementally adjusted version of the schedule.

5. The method of claim 4, wherein the HVAC system is controlled according to the user selection of the current temperature setpoint from the time of receiving the user selection to a time when a subsequent temperature setpoint of the incrementally adjusted version of the setpoint schedule generated for the one of the periodic time intervals is reached.

6. The method of claim 1, further comprising:

receiving, for one of the periodic time intervals, a user modification to a temperature setpoint of the incrementally adjusted version of the schedule generated for the one of the periodic time intervals;

incorporating the user modification into incrementally adjusted versions of the schedule generated for subsequent periodic time intervals; and

for the subsequent periodic time intervals, controlling the HVAC system based on the incrementally adjusted versions of the scheduled that incorporate the user modification.

7. The method of claim 6 wherein for each periodic time interval following the one of the periodic time intervals, the incrementally adjusted version of the schedule is generated by incrementally adjusting the temperature setpoint as defined by the user modification rather than the temperature setpoint as defined by the schedule of temperature setpoint.

8. An intelligent network-connected thermostat for controlling an operation of an HVAC system in a smart home environment, the thermostat comprising:

HVAC control circuitry operable to actuate one or more elements of the HVAC system;

one or more sensors for measuring characteristics of the smart home environment; and

a processor coupled to the HVAC control circuitry and the one or more sensors and operable to cause the thermostat to perform operations including;

identifying an schedule of temperature setpoints;

beginning with the schedule, for each of a succession of periodic time intervals that are each relatively short in comparison to an overall optimization time period, generating an incrementally adjusted version of the schedule as part of an automated schedule adjustment process, the incremental change being directed to a setpoint temperature of the number of temperature setpoints and causing less energy usage during one of the periodic time intervals as compared to a previous one of the periodic time intervals, wherein causing less energy usage comprises having a heating system of the HVAC system or an air conditioner of the HVAC system activated less than in accordance with the identified schedule; and

for each of the succession of periodic time intervals, controlling the HVAC system according to the incrementally adjusted version of the schedule generated for the periodic time interval.

9. The thermostat of claim 8, wherein generating an incrementally adjusted version of the schedule includes, for each periodic time interval, offseting a temperature of at least one temperature setpoint of the schedule in a direction that reduces energy consumption by the HVAC system.

10. The thermostat of claim 9, wherein the processor is further operable to cause the thermostat to perform operations including:

receiving, during one of the succession of periodic time intervals, a user modification to a current temperature setpoint or to a temperature setpoint of the incrementally adjusted version of the schedule.

11. The thermostat of claim 10, wherein in response to receiving a user modification to a current temperature setpoint, the offset for subsequent periodic time intervals is at least temporarily reduced.

12. The thermostat of claim 11, wherein in response to receiving a user modification to a temperature setpoint of the incrementally adjusted version of the original schedule, the offset for subsequent periodic time intervals is at least temporarily reduced by an amount greater than the reduction resulting from a user modification to a current temperature setpoint.

13. The thermostat of claim 10, wherein in response to receiving a user modification to a current temperature setpoint or to a temperature setpoint of the incrementally adjusted version of the schedule, the offset for subsequent periodic time intervals is reduced by an amount that decreases over time.

14. A tangible non-transitory computer-readable storage medium including instructions that, when executed by a computer processor, cause the computer processor to perform operations including:

identifying an schedule of temperature setpoints, the original schedule of temperature setpoints defining a number of temperature setpoints over a time period;

beginning with the schedule, for each of a succession of periodic time intervals that are each relatively short in comparison to an overall optimization time period, generating an incrementally adjusted version of the schedule as part of an automated schedule adjustment process, the incremental change being directed to a setpoint temperature of the number of temperature setpoints and causing less energy usage during one of the periodic time intervals as compared to a previous one of the periodic time intervals, wherein causing less energy usage comprises having a heating system of the HVAC system or an air conditioner of the HVAC system activated less than in accordance with the identified schedule; and

for each of the succession of periodic time intervals, controlling the HVAC system according to the incrementally adjusted version of the schedule generated for the periodic time interval.

15. The storage medium of claim 14 further including instructions that, when executed by the computer processor, cause the computer processor to perform additional operations including:

identifying a first subset of temperature setpoints within the schedule of temperature setpoints, the first subset of temperature setpoints corresponding to a first sub-interval of the time period over which the original schedule of temperature setpoints is defined, the first sub-interval corresponding to a time period during which a structure associated with the HVAC system is likely to be occupied; and

identifying a second subset of temperature setpoints within the schedule of temperature setpoints, the second subset of temperature setpoints corresponding to a second sub-interval of the time period over which the schedule of temperature setpoints is defined, the second sub-interval corresponding to a time period during which a structure associated with the HVAC system is unlikely to be occupied;

wherein generating an incrementally adjusted version of the schedule includes adjusting the first subset of temperature setpoints differently than the second subset of temperature setpoints, the second subset being adjusted to reduce energy usage by a greater amount than an amount resulting from adjustments made to the first subset.

16. The storage medium of claim 14 further including instructions that, when executed by the computer processor, cause the computer processor to perform additional operations including:

identifying a first subset of temperature setpoints within the schedule of temperature setpoints, the first subset of temperature setpoints corresponding to a first sub-interval of the time period over which the schedule of temperature setpoints is defined;

wherein for a first set of the succession of periodic time intervals, generating an incrementally adjusted version of the schedule includes modifying temperature setpoints of the first subset of temperature setpoints.

17. The storage medium of claim 16 further including instructions that, when executed by the computer processor, cause the computer processor to perform additional operations including:

identifying a second subset of temperature setpoints within the schedule of temperature setpoints, the second subset of temperature setpoints corresponding to a second sub-interval of the time period over which the schedule of temperature setpoints is defined;

wherein for a second set of the succession of periodic time intervals following the first set of periodic time intervals, generating an incrementally adjusted version of the schedule includes modifying temperature setpoints of the second subset of temperature setpoints while simultaneously modifying temperature setpoints of the first subset of temperature setpoints.

18. The storage medium of claim 17 further including instructions that, when executed by the computer processor, cause the computer processor to perform additional operations including:

identifying a third subset of temperature setpoints within the schedule of temperature setpoints, the third subset of temperature setpoints corresponding to a third sub-interval of the time period over which the schedule of temperature setpoints is defined;

wherein for a third set of the succession of periodic time intervals following the second set of periodic time intervals, generating an incrementally adjusted version of the schedule includes modifying temperature setpoints of the third subset of temperature setpoints while simultaneously modifying temperature setpoints of the first subset of temperature setpoints and temperature setpoints of the second subset of temperature setpoints.

19. The storage medium of claim 18 wherein the temperature setpoints of the first subset, second subset, and third subset that are modified are all modified at the same rate of change.

20. The storage medium of claim 18 wherein the temperature setpoints of at least one of the first subset, second subset, and third subset that are modified are modified at a different rate of change in response to a user input.