Facilitating ambient temperature measurement accuracy in an HVAC controller having internal heat-generating components

• US 9,360,229 B2
• Filed: 04/26/2013
• Issued: 06/07/2016
• Est. Priority Date: 04/26/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Modi, Yash, Matsuoka, Yoky, Filson, John B.
• Primary Examiner(s): Kasenge, Charles
• Application Number:
  US13/871,734
• Publication Number:
  US 20140324232A1
• Time in Patent Office: 1,138 Days
• Field of Search: 700/276, 700/278, 700/299, 700/300, 713/300, 713/320, 713/321, 236/91.F
• 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 11/523 for displaying temperature data
• CPC Class Codes: F24F 11/56 Remote control
• CPC Class Codes: F24F 11/58 using Internet communication
• 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 11/66 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 15/02 electric
• CPC Class Codes: G05D 23/1931 to control the temperature of one space
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A thermostat may include one or more temperature sensors, and a processing system configured to be in operative communication with an HVAC system. The processing system may be configured to operate a first operating state characterized by relatively low power consumption and a corresponding relatively low associated heat generation, and a second operating state characterized by relatively high power consumption and a corresponding relatively high associated heat generation. During time intervals in which the processing system is operating in the first operating state, the processing system may process the temperature sensor measurements according to a first ambient temperature determination algorithm to compute the determined ambient temperature. During time intervals in which the processing system is operating in the second operating state, the processing system may process the temperature sensor measurements according to a second ambient temperature determination algorithm to compute the determined ambient temperature.

Claims

1. A thermostat, comprising:

a housing;

a user interface;

one or more temperature sensors, each of the one or more temperature sensors being configured to provide temperature sensor measurements, wherein said one or more temperature sensors includes a first temperature sensor, a second temperature sensor, and a third temperature sensor, each being positioned at different locations relative to the housing; and

a processing system disposed within the housing, the processing system being configured to be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements, in operative communication with one or more input devices including said user interface for determining a setpoint temperature, and in still further operative communication with a heating, ventilation, and air conditioning (HVAC) system to control the HVAC system based on a comparison of a determined ambient temperature and the setpoint temperature, wherein said processing system is configured to;

(i) operate in a plurality of operating states including a first operating state characterized by relatively low power consumption and a corresponding relatively low associated heat generation and a second operating state characterized by relatively high power consumption and a corresponding relatively high associated heat generation;

(ii) during time intervals in which the processing system is operating in the first operating state, process the temperature sensor measurements according to a first ambient temperature determination algorithm based on readings from said first and second temperature sensors and not based on readings from said third temperature sensor to compute the determined ambient temperature; and

(iii) during time intervals in which the processing system is operating in the second operating state, process the temperature sensor measurements according to a second ambient temperature determination algorithm based on readings from said third temperature sensor to compute the determined ambient temperature.

2. The thermostat of claim 1, wherein the third temperature sensor is disposed on a portion of the thermostat such that the third temperature sensor is less susceptible to the heating by the processing system than the first temperature sensor.

3. The thermostat of claim 1, wherein the second ambient temperature determination algorithm calculates the determined ambient temperature using (i) temperature measurements provided by the third temperature sensor, and (ii) an offset calculated during the time intervals in which the processing system is operating in the first operating state.

4. The thermostat of claim 1, wherein the thermostat comprises a first modular section and a second modular section, the third temperature sensor being disposed in the first modular section, the first temperature sensor being disposed in the second modular section, and the second temperature sensor being disposed in the second modular section.

5. The thermostat of claim 1, wherein the second temperature sensor is disposed on a portion of the thermostat such that the second temperature sensor is more susceptible to the heating by the processing system than the first temperature sensor and the third temperature sensor.

6. The thermostat of claim 1, wherein the processing system comprises:

a low-power processor; and

a high-power processor, wherein the high-power processor is configured to calculate temperature thresholds to be stored by the low-power processor, the low-power processor being configured to wake the high-power processor from a sleep state when one or more of the thresholds are violated by the determined ambient temperature.

7. The thermostat of claim 1, wherein during the time intervals in which the processing system is operating in the second operating state, the processing system is further configured to:

(i) detect a change in the determined ambient temperature; and

(ii) switch from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after detecting said change in the determined ambient temperature.

8. The thermostat of claim 7, wherein the processing system is further configured to switch from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after determining that the processing system has been operating in the second operating state for a predetermined time interval.

9. A method of compensating for internal heating in a thermostat, the method comprising:

determining, using a processing system of the thermostat, a current operating state of the processing system, wherein the thermostat comprises;

a housing;

a user interface;

one or more temperature sensors, each of the one or more temperature sensors being configured to provide temperature sensor measurements, wherein said one or more temperature sensors includes a first temperature sensor, a second temperature sensor, and a third temperature sensor, each being positioned at different locations relative to the housing; and

a processing system disposed within the housing, the processing system being configured to be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements, in operative communication with one or more input devices including said user interface for determining a setpoint temperature, and in still further operative communication with a heating, ventilation, and air conditioning (HVAC) system to control the HVAC system based on a comparison of a determined ambient temperature and the setpoint temperature, wherein said processing system is configured to operate in a plurality of operating states including a first operating state characterized by relatively low power consumption and a corresponding relatively low associated heat generation and a second operating state characterized by relatively high power consumption and a corresponding relatively high associated heat generation;

during time intervals in which the processing system is operating in the first operating state, processing the temperature sensor measurements according to a first ambient temperature determination algorithm based on readings from said first and second temperature sensors and not based on readings from said third temperature sensor to compute the determined ambient temperature; and

during time intervals in which the processing system is operating in the second operating state, processing the temperature sensor measurements according to a second ambient temperature determination algorithm based on readings from said third temperature sensor to compute the determined ambient temperature.

10. The method of claim 9, wherein the third temperature sensor is disposed on a portion of the thermostat such that the third temperature sensor is less susceptible to the heating by the processing system than the first temperature sensor.

11. The method of claim 9, wherein the second ambient temperature determination algorithm calculates the determined ambient temperature using (i) temperature measurements provided by the third temperature sensor, and (ii) an offset calculated during the time intervals in which the processing system is operating in the first operating state.

12. The method of claim 9, wherein the thermostat comprises a first modular section and a second modular section, the third temperature sensor being disposed in the first modular section, the first temperature sensor being disposed in the second modular section, and the second temperature sensor being disposed in the second modular section.

13. The method of claim 9, wherein the second temperature sensor is disposed on a portion of the thermostat such that the second temperature sensor is more susceptible to the heating by the processing system than the first temperature sensor and the third temperature sensor.

14. The method of claim 9, wherein the processing system comprises:

a low-power processor; and

a high-power processor, wherein the high-power processor is configured to calculate temperature thresholds to be stored by the low-power processor, the low-power processor being configured to wake the high-power processor from a sleep state when one or more of the thresholds are violated by the determined ambient temperature.

15. The method of claim 9, further comprising, during the time intervals in which the processing system is operating in the second operating state:

detecting a change in the determined ambient temperature; and

switching from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after detecting said change in the determined ambient temperature.

16. The method of claim 15, wherein the processing system is further configured to switch from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after determining that the processing system has been operating in the second operating state for a predetermined time interval.

17. A thermostat, comprising:

one or more temperature sensors comprising a first temperature sensor, a second temperature sensor, and a third temperature sensor, each of the one or more temperature sensors being configured to provide temperature sensor measurements, the third temperature sensor being located such that it is less susceptible to internal heating effects than the first temperature sensor and the second temperature sensor; and

a processing system, the processing system being configured to be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements, and configured to be in operative communication with a heating, ventilation, and air conditioning (HVAC) system to control the HVAC system based on a comparison of a determined ambient temperature and a setpoint temperature, wherein said processing system is configured to;

(i) operate in a plurality of operating states including a first operating state characterized by relatively low power consumption and a corresponding relatively low associated heat generation and a second operating state characterized by relatively high power consumption and a corresponding relatively high associated heat generation;

(ii) during time intervals in which the processing system is operating in the first operating state, process the temperature sensor measurements according to a first ambient temperature determination algorithm to compute the determined ambient temperature; and

(iii) during time intervals in which the processing system is operating in the second operating state, process the temperature sensor measurements according to a second ambient temperature determination algorithm to compute the determined ambient temperature, wherein the second ambient temperature determination algorithm uses temperature sensor measurements from the third temperature sensor.

18. The thermostat of claim 17 wherein the first ambient temperature determination algorithm uses temperature sensor measurements from the first temperature sensor and the second temperature sensor.

19. The thermostat of claim 17 wherein the second temperature sensor is disposed such that the second temperature sensor is more susceptible to internal heating effects than the first temperature sensor and the third temperature sensor.

20. The thermostat of claim 17 wherein the processing system is further configured to switch from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after determining that the processing system has been operating in the second operating state for a predetermined time interval.