HVAC CONTROLLER CONFIGURATIONS THAT COMPENSATE FOR HEATING CAUSED BY DIRECT SUNLIGHT

• US 20130204442A1
• Filed: 03/15/2013
• Published: 08/08/2013
• Est. Priority Date: 11/19/2010
• Status: Active Grant

• Current Assignee: Nest Labs Incorporated (Alphabet Inc.)
• Original Assignee: Nest Labs Incorporated (Alphabet Inc.)
• Inventors: MODI, YASH, MATSUOKA, YOKY, FILSON, JOHN B.
• Granted Patent: US 9,714,772 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 11/62 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 2120/00 Control inputs relating to users or occupants
• CPC Class Codes: F24F 2130/20 Sunlight
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: G05D 23/1902 characterised by the use of a variable reference value
• CPC Class Codes: G05D 23/1928 sensing the temperature of one space
• CPC Class Codes: G06F 17/142 Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm

Abstract

A thermostat may include a housing, a user interface, temperature sensors providing temperature sensor measurements, and a processing system configured to control an HVAC system based on a comparison of a determined ambient temperature and a setpoint temperature. The thermostat may (i) determine time intervals in which direct sunlight is incident on the thermostat; (ii) during time intervals in which direct sunlight is not incident on the thermostat, 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 it is determined that direct sunlight is incident on the thermostat, process the temperature sensor measurements according to a second ambient temperature determination algorithm to compute the determined ambient temperature that compensates for a heating of the thermostat caused by the direct sunlight.

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; 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) determine time intervals in which direct sunlight is incident on said housing;

(ii) during time intervals in which direct sunlight is not incident on said housing, 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 it is determined that direct sunlight is incident on said housing, process the temperature sensor measurements according to a second ambient temperature determination algorithm to compute the determined ambient temperature, said second ambient temperature determination algorithm being characterized in that compensation is made for a heating of the thermostat caused by the direct sunlight that is incident on said housing.

2. The thermostat of claim 1, further comprising an ambient light sensor (ALS) that is in operative communication with the processing system, wherein the processing system is configured to receive ambient light measurements from the ALS in order to determine the time intervals in which direct sunlight is incident on said housing.

3. The thermostat of claim 2, wherein the processing system is further configured to construct an ALS profile of an enclosure in which the thermostat is installed using the ambient light measurements provided by the ALS, wherein the ALS profile is predictive of the time intervals in which direct sunlight is incident on said housing.

4. The thermostat of claim 1, wherein the one or more temperature sensors comprises a first temperature sensor, a second temperature sensor, and a third temperature sensor.

5. The thermostat of claim 4, wherein the third temperature sensor is disposed on a rear portion of the thermostat such that the third temperature sensor is less susceptible to the heating of the thermostat caused by the direct sunlight incident on said housing than the first temperature sensor or the second temperature sensor.

6. The thermostat of claim 5, wherein said second ambient temperature determination algorithm calculates said determined ambient temperature using temperature measurements provided by the third temperature sensor.

7. The thermostat of claim 4, wherein said first ambient temperature determination algorithm calculates said determined ambient temperature using temperature measurements provided by the first temperature sensor and the second temperature sensor.

8. 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 and ambient light 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 temperature sensor measurements received from the at least one temperature sensor or an ambient light sensor.

9. The thermostat of claim 1, wherein during the time intervals in which it is determined that direct sunlight is incident on said housing, the processing system is further configured to:

(i) detect an increase in the determined ambient temperature above a threshold amount; and

(ii) switch from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after detecting said increase in the determined ambient temperature above the threshold amount.

10. A method of compensating for direct sunlight heating in a thermostat, the method comprising:

determining, using a processing system of the thermostat, time intervals in which direct sunlight is incident the thermostat, wherein the thermostat includes;

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; and

the 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;

during time intervals in which direct sunlight is not incident on the thermostat, processing the temperature sensor measurements according to a first ambient temperature determination algorithm to compute the determined ambient temperature; and

during time intervals in which it is determined that direct sunlight is incident on the thermostat, processing the temperature sensor measurements according to a second ambient temperature determination algorithm to compute the determined ambient temperature, said second ambient temperature determination algorithm being characterized in that compensation is made for a heating of the thermostat caused by the direct sunlight that is incident on the thermostat.

11. The method of claim 10, wherein the thermostat further comprises an ambient light sensor (ALS) that is in operative communication with the processing system, wherein the processing system is configured to receive ambient light measurements from the ALS in order to determine the time intervals in which direct sunlight is incident on said housing.

12. The method of claim 11, further comprising constructing an ALS profile of an enclosure in which the thermostat is installed using the ambient light measurements provided by the ALS, wherein the ALS profile is predictive of the time intervals in which direct sunlight is incident on said housing.

13. The method of claim 10, wherein the one or more temperature sensors comprises a first temperature sensor, a second temperature sensor, and a third temperature sensor.

14. The method of claim 13, wherein the third temperature sensor is disposed on a rear portion of the thermostat such that the third temperature sensor is less susceptible to the heating of the thermostat caused by the direct sunlight incident on the thermostat than the first temperature sensor or the second temperature sensor.

15. The method of claim 14, wherein said second ambient temperature determination algorithm calculates said determined ambient temperature using temperature measurements provided by the third temperature sensor.

16. The method of claim 13, wherein said first ambient temperature determination algorithm calculates said determined ambient temperature using temperature measurements provided by the first temperature sensor and the second temperature sensor.

17. The method of claim 10, wherein the processing system comprises:

a low-power processor; and

a high-power processor, wherein the high-power processor is configured to calculate temperature and ambient light 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 temperature sensor measurements received from the at least one temperature sensor or an ambient light sensor.

18. The method of claim 10, wherein during the time intervals in which it is determined that direct sunlight is incident on said housing, the processing system is further configured to:

(i) detect an increase in the determined ambient temperature above a threshold amount; and

(ii) switch from the first ambient temperature determination algorithm to the second ambient temperature determination algorithm after detecting said increase in the determined ambient temperature above the threshold amount.

19. A method of compensating for sunlight heating a thermostat, the method comprising:

processing temperature measurements from one or more temperature sensors;

computing a determined ambient temperature using the temperature measurements;

detecting that the determined ambient temperature is being affected by the sunlight heating the thermostat; and

compensating for the sunlight heating the thermostat when calculating the determined ambient temperature while the determined ambient temperature is being affected by the sunlight heating the thermostat.

20. The method of claim 19 further comprising:

processing light measurements from a light sensor; and

using the light measurements and the temperature measurements to detect that the determined ambient temperature is being affected by the sunlight heating the thermostat.