AUXILIARY STAGE CONTROL OF MULTISTAGE THERMOSTATS

• US 20070267508A1
• Filed: 12/28/2005
• Published: 11/22/2007
• Est. Priority Date: 12/28/2005
• Status: Active Grant

• Current Assignee: Ademco Inc. (Resideo Technologies, Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Leen, Cary, Hoglund, Steven, Tessier, Patrick, Kidder, Kenneth
• Granted Patent: US 7,644,869 B2
• Time in Patent Office: Days
• US Class Current: 236/49.100
• 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 11/52 Indication arrangements, e.g. displays
• 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 11/65 for selecting an operating mode
• CPC Class Codes: G05D 23/1902 characterised by the use of a variable reference value
• CPC Class Codes: G05D 23/1932 to control the temperature of a plurality of spaces

Abstract

Systems and methods for the auxiliary stage control of multistage thermostats are disclosed. An illustrative multistage thermostat for a multistaged HVAC system installed within a building or structure can include a processor having a control algorithm adapted to operate the thermostat in either a normal mode for achieving rapid temperature changes within the building or structure or an economy mode for conserving energy usage. In the economy mode of operation, the thermostat can be configured to determine a target time for achieving a temperature setpoint by either delaying or suppressing activation of the system'"'"'s auxiliary stage. The target time can be adjusted in part based on the past usage characteristics of the auxiliary stage, the behavior of the user, and/or the progress of the primary stage in achieving the setpoint change without operating the auxiliary stage.

Claims

1. A method of controlling an HVAC system installed within a building or structure, the HVAC system including a primary stage and an auxiliary stage, the method comprising the steps of:

providing a multistage thermostat controller having a normal mode of operation and an economy mode of operation;

receiving a temperature setpoint to adjust the temperature within the building or structure;

sensing the temperature within the building or structure and activating the primary stage if the sensed temperature is different than the temperature setpoint;

determining a target time to reach the temperature setpoint; and

achieving the temperature setpoint at or near said target time while delaying or suppressing activation of the auxiliary stage.

2. The method of claim 1, wherein said step of receiving a temperature setpoint to adjust the temperature within the building or structure includes the step of receiving an input or command from a user or another controller.

3. The method of claim 1, wherein said step of determining a target time to achieve the temperature setpoint is accomplished at least in part using a table of times versus temperatures stored within a memory unit of the thermostat controller.

4. The method of claim 1, wherein said step of determining a target time to achieve the temperature setpoint is accomplished at least in part using feedback from an exterior temperature sensor.

5. The method of claim 1, wherein said step of determining a target time to achieve the temperature setpoint is based at least in part on the past usage characteristics of the auxiliary stage.

6. The method of claim 1, wherein said step of determining a target time to achieve the temperature setpoint includes the steps of:

computing a setup amount parameter representing the difference between the temperature setpoint and the sensed temperature within the building or structure; and

computing an auxiliary ramp rate parameter representing an estimate of the heating or cooling capacity of both the primary and auxiliary stages.

7. The method of claim 6, further comprising the step of activating the auxiliary stage if the current sensed temperature within the building or structure is less than or equal to a crossover temperature point determined from the auxiliary ramp rate parameter.

8. The method of claim 1, further comprising the steps of:

activating the primary stage once the temperature setpoint is received;

sensing the temperature change within the building or structure over a period of time; and

comparing the temperature change parameter against a minimum progress parameter and activating the auxiliary stage if said temperature change parameter is less than said minimum progress parameter.

9. The method of claim 1, wherein the multistage thermostat controller is adapted to adjust the target time based at least in part on user input made subsequent to receiving said temperature setpoint.

10. The method of claim 1, further comprising the steps of:

determining whether at least one setback change has been made prior to achieving said temperature setpoint; and

adjusting the target time earlier or later based at least in part on said at least one setback change.

11. The method of claim 10, further comprising the step of adjusting the target time based at least in part on the number of setback changes made.

12. The method of claim 10, further comprising the step of adjusting the target time based at least in part on the time between two or more setback changes.

13. The method of claim 10, further comprising the step of adjusting the target time based at least in part on the magnitude or direction of said at least one setback change.

14. The method of claim 1, wherein said primary and auxiliary stages are each heating stages.

15. The method of claim 1, wherein said primary and auxiliary stages are each cooling stages.

16. The method of claim 1, wherein said multistage thermostat controller is a non-programmable thermostat.

17. The method of claim 1, wherein said multistage thermostat controller is a programmable thermostat.

18. A multistage thermostat for controlling an HVAC system installed within a building or structure, the HVAC system including a primary stage and an auxiliary stage, said thermostat controller comprising:

a processor including a control algorithm adapted to run the thermostat controller in either a normal mode of operation for achieving rapid temperature changes within the building or structure or an economy mode of operation for conserving energy usage of the auxiliary stage; and

a user interface for receiving temperature setpoint changes from a user or other controller;

wherein the thermostat controller in said economy mode of operation is adapted to determine a target time for achieving the setpoint changes while delaying or suppressing activation of the auxiliary stage.

19. The multistage thermostat of claim 18, wherein the thermostat controller in said normal mode of operation is adapted to immediately activate the auxiliary stage in response to a temperature setpoint change.

20. The multistage thermostat of claim 18, wherein the thermostat controller in said economy mode of operation is adapted to delay or suppress activation of the auxiliary stage in response to a temperature setpoint change.

21. The multistage thermostat of claim 18, further comprising a memory unit for storing data regarding the past usage characteristics of the primary and/or auxiliary stages and the temperature setpoint changes received.

22. The multistage thermostat of claim 18, wherein said multistage thermostat is a non-programmable thermostat.

23. The multistage thermostat of claim 18, wherein said multistage thermostat is a programmable thermostat.

24. The multistage thermostat of claim 18, wherein said primary stage comprises a heat pump.

25. The multistage thermostat of claim 18, wherein said auxiliary stage comprises an electrical resistance strip.

26. An HVAC system, comprising:

a heating or cooling device having a primary stage and one or more auxiliary stages;

a non-programmable multistage thermostat controller having a normal mode of operation and an economy mode of operation; and

a user interface for receiving temperature setpoint changes;

wherein the thermostat controller in said economy mode of operation is adapted to delay or suppress activation of the one or more auxiliary stages in response to a change in the temperature setpoint.