System for determining ambient temperature

Patent metadata

Field	Value
Publication number	US-9335769-B2
Application number	US-201213447138-A
Country	US
Kind code	B2
Filing date	Apr 13, 2012
Priority date	Dec 4, 2007
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

A mechanism for indicating ambient temperature of an enclosure from temperatures determined within the enclosure. The temperatures may be obtained from two or more sensors at each of two or more locations within the enclosure. The enclosure may include heat generating components such as electronics. The enclosure may also incorporate one or more dynamic components that emanate sudden amounts of heat. The present mechanism compensates for such heat sources with a compensating scheme.

First claim

What is claimed is:

1. A thermostat that functions to provide control signals to temperature control equipment to maintain a desired temperature in a space, comprising:
a housing;
one or more heat generating elements in the housing, wherein during operation of the thermostat, the one or more heat generating elements cause a first region within the housing to be warmer than a second region within the housing;
a first temperature sensor for reporting a measure that is related to the temperature in the first region;
a second temperature sensor for reporting a measure that is related to the temperature in the second region;
a controller in communication with the first temperature sensor and the second temperature sensor, the controller determining a measure related to an ambient temperature outside of the housing based, at least in part, on the measure that is related to the temperature in the first region reported by the first temperature sensor and the measure that is related to the temperature in the second region reported by the second temperature sensor; and
wherein:
the thermostat uses the measure related to the ambient temperature outside of the housing to determine one or more control signals for controlling temperature control equipment;
the thermostat is powered, at least in part, by electrical energy;
the one or more heat generating elements generate heat by consuming the electrical energy;
a level of electrical energy needed to power the thermostat and/or the one or more heat generating elements changes over time ranging between a first non-zero amount to a second non-zero amount;
the first temperature sensor and/or the second temperature sensor report a measure that is related to the temperature in the first region or the second region, respectively, which changes over time in a rapid or slow manner, correspondingly, at least in part, to the changes of energy over time ranging between a first non-zero amount to a second non-zero amount needed to power the thermostat incorporating the heat generating elements; and
the changes over time in a rapid manner are compensated so as to avoid affecting determination of ambient temperature changes over time in a slow manner of the first temperature sensor and/or the second temperature sensor which reports a measure that is related to the temperature in the first region or the second region, respectively, wherein the controller is configured to compensate for the change over time when a rise of a measure of the first sensor or the second sensor is greater than a predetermined rate of X degrees Fahrenheit (F) per second.

2. The thermostat of claim 1 , wherein:
the one or more heat generating elements comprises a display backlight which is at certain times turned on resulting in one or more changes in a rapid manner.

3. The thermostat of claim 1 , wherein the controller compensates for the temperature in the first region or the second region, respectively, which changes over time in a rapid or slow manner, correspondingly, at least in part, to changes of energy needed over time to power one or more heat generating elements, to result in the controller determining the measure related to an ambient temperature outside of the housing, at least in part, on the measure that is related to the temperature in the first region reported by the first temperature sensor and the measure that is related to the temperature in the second region reported by the second temperature sensor.

4. The thermostat of claim 3 , wherein the measure related to the ambient temperature determined by the controller is relatively independent of the level of the electrical energy needed to power the thermostat.

5. The thermostat of claim 3 , wherein the controller determines the measure related to the ambient temperature outside of the housing based, at least in part, on a predetermined relationship between the measure related to the ambient temperature outside of the housing, the measure related to the temperature in the first region reported by the first temperature sensor and the measure related to the temperature in the second region reported by the second temperature sensor.

6. The thermostat of claim 5 , wherein the thermostat is powered by a level of electrical energy that changes over time, and wherein the measure related to the ambient temperature is relatively independent of the level of electrical energy powering the thermostat.

7. The thermostat of claim 3 , wherein a change over time in a rapid manner is a rise of a measure of the first sensor or the second sensor of greater than a predetermined rate of X degrees F. per second.

8. The thermostat of claim 3 , further comprising:
a third temperature sensor for reporting a measure that is related to the temperature in a third region within the housing;
the controller determining a measure related to an air flow direction and/or air flow magnitude about the housing that is based, at least in part, on the measure related to the temperature in the third region reported by the third temperature sensor; and
the controller using the measure related to the air flow direction and/or air flow magnitude about the housing when determining the measure related to the ambient temperature outside of the housing.

9. The thermostat of claim 3 , further comprising:
a third temperature sensor for reporting a measure that is related to the temperature in a third region within the housing; and
wherein:
the measure related to an ambient temperature outside of the housing based, at least in part, on the measure that is related to the temperature in the first region reported by the first temperature sensor, the measure that is related to the temperature in the second region reported by the second temperature sensor, and the measure that is related to the temperature in the third region reported by the third temperature sensor, is according to
T Ambient =( A*T 1 +B*T 2 +C*T 3 +E *(Final−(Final−Initial)* e ^(− t/tau ))+ D )/( A+B+C );

T 1 is the measure reported by the first temperature sensor;
T 2 is the measure reported by the second temperature sensor;
T 3 is the measure reported by the third temperature sensor;
E is a dynamic heat source factor;
Final is a new heat source level;
Initial is an old heat source level before a change;
t is time that lapsed since a change;
tau is a time constant;
A, B, C, D and E are constants;
a dynamic heat source is a heat generating element that is powered by changes of energy over time which results, at least in part, the temperature in the first, second and/or third region, changing over time in a rapid manner; and
the rapid manner is greater than a predetermined rate of X degrees F. per second.

10. A method for determining an ambient temperature outside an enclosure, comprising:
detecting a first temperature over a period of time at a first location in an enclosure;
detecting a second temperature over the period of time at a second location in the enclosure;
determining a first change of the first temperature over the period of time, from the first temperature over the period of time;
detecting a second change of the second temperature over the period of time, from the second temperature over the period of time;
selecting from the first change of the first temperature and the second change of the second temperature, a greatest change of temperature, over the period of time;
determining whether the greatest change of temperature is dynamic;
a change of temperature is dynamic when the change per period of time exceeds a predetermined rate of X degrees Fahrenheit (F) per second;
generating a relationship between an ambient temperature outside of the enclosure and th

Assignees

• Aljabari Mohammad
• Lunacek Michael
• Tauer Jeff
• Honeywell Int Inc

Inventors

• Aljabari Mohammad
• Lunacek Michael
• Tauer Jeff

Classifications

• F24F11/63

  Electronic processing · CPC title

• F24F11/52 Primary

  Indication arrangements, e.g. displays · CPC title

• G01K3/14

  in respect of space · CPC title

• G01K1/00

  Details of thermometers not specially adapted for particular types of thermometer (circuits for reducing thermal inertia G01K7/42) · CPC title

• G01K7/42

  Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature · CPC title