Controlled setpoint recovery

• US 5,454,511 A
• Filed: 09/22/1994
• Issued: 10/03/1995
• Est. Priority Date: 09/22/1994
• Status: Expired due to Term

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Shah, Rajendra K., Van Ostrand, William F., Werbowsky, Laurie L., Pierret, Peter G.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US08/310,525
• Time in Patent Office: 376 Days
• Field of Search: 236/46 R:47, 165/12, 165/29, 364/505, 364/557
• US Class Current: 236/46.00R
• CPC Class Codes: F24F 11/00 Control or safety arrangements
• 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 11/61 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 2110/10 Temperature
• CPC Class Codes: G05D 23/1904 variable in time

Abstract

A process is disclosed for controlling the operative setpoint of a thermostat during transition from a currently scheduled setpoint temperature to the next scheduled setpoint temperature. The operative setpoint is changed by small amounts at calculated time intervals. The time intervals are a function of the transition periods allocated for different types of systems for air conditioning air that may be operatively connected to the thermostat as well as the difference between the currently scheduled setpoint temperature and the next scheduled setpoint temperature.

Claims

1. A process for controlling the operative setpoint temperature of a thermostat when the currently scheduled setpoint temperature is to change to the next scheduled setpoint temperature at a predetermined time in the future, said process comprising the steps of:

determining whether the thermostat is to operate on the basis of a first or a second type of system for conditioning air being operatively connected to the thermostat;

selecting a predefined period of time during which the currently scheduled setpoint temperature is to change to the next scheduled setpoint temperature depending on whether the thermostat is to operate on the basis of a first or a second type of system for conditioning air being operatively connected to the thermostat;

determining when the current time is within the selected predefined period of time of the scheduled change time to the next scheduled set point temperature; and

changing the operative setpoint temperature of the thermostat by predefined amounts of temperature in calculated increments of time until the scheduled change time to the next scheduled setpoint temperature occurs whereby the operative setpoint of the thermostat gradually changes to the next scheduled setpoint during the selected predefined period of time.

2. The process of claim 1 wherein said step of changing the operative setpoint temperature by predefined amounts in calculated increments of time comprises the steps of:

calculating an increment of time that must elapse before the operative setpoint is to change; and

changing the operative setpoint each time the calculated increment of time elapses.

3. The process of claim 2 wherein said step of calculating an increment of time during which the operative setpoint is to change comprises the step of:

dividing a portion of the selected predefined period of time by the difference between the next scheduled setpoint and the currently scheduled setpoint so as to produce an increment of time that must elapse before each successive change in the operative setpoint temperature.

4. The process of claim 3 wherein said step of changing the operative setpoint each time the calculated increment of time elapses comprises the step of:

changing the operative setpoint by one-tenth of a degree each time the increment of time elapses.

5. The process of claim 3 wherein the portion of the predefined period of time is equal to one-tenth of the predefined period of time.

6. The process of claim 5 wherein the difference between the next scheduled setpoint and the currently scheduled setpoint must be at least two degrees of temperature change.

7. The process of claim 3 wherein the difference between the next scheduled setpoint and the currently scheduled setpoint must be at least two degrees of temperature change.

8. The process of claim 1 wherein said step of determining when the current time is within a predefined period of time of the scheduled change time for the next scheduled setpoint temperature comprises the step of:

determining when the current time plus the selected predefined period of time is equal to the scheduled change time for the next scheduled setpoint temperature.

9. The process of claim 8 further comprising the step of:

setting a control flag when the current time plus the selected predefined period of time is equal to the scheduled change time to the next scheduled setpoint temperature so as to authorize said step of changing the operative setpoint temperature of the thermostat by predefined amounts during the time in which the control flag is set.

10. The process of claim 9 further comprising the step of:

clearing the control flag when the current time equals the scheduled change time to the next scheduled setpoint temperature thereby terminating said step of changing the operative setpoint temperature of the thermostat by predefined amounts.

11. The process of claim 8 wherein said step of selecting a predefined period of time during which the currently scheduled setpoint is to change to the next scheduled setpoint comprises the steps of:

selecting a first period of time as the predefined period of time if the thermostat is to operate on the basis of a heat pump system being connected to the thermostat; and

selecting a second period of time as the predefined period of time if the thermostat is to operate on the basis that a system for conditioning air other than a heat pump is connected to the thermostat.

12. The process of claim 11 wherein said step of changing the operative setpoint of the thermostat by predefined amounts of temperature in calculated increments of time comprises:

dividing a portion of the first period of time by the difference between the next scheduled setpoint and the currently scheduled setpoint so as to define an increment of time that must elapse between successive changes in the setpoint temperature when it is determined that the thermostat is to operate on the basis of a heat pump system being connected to the thermostat; and

dividing a portion of the second period of time by the difference between the next scheduled setpoint and the currently scheduled setpoint so as to define an increment of time that must elapse between successive changes in the setpoint temperature when it is determined that the thermostat is to operate on the basis that a system for conditioning air other than a heat pump system is connected to the thermostat.

13. The process of claim 1 wherein said step of determining whether the thermostat is to operate on the basis of a first or second type of system for conditioning air being operatively connected to the thermostat comprises the step of:

checking the status of a switch indicating whether the thermostat is to operate on the basis of a first or second type of system for conditioning air being operatively connected to the thermostat.

14. The process of claim 1 further comprising the step of:

checking whether a recovery authorization continues to exist before changing the operative setpoint temperature of the thermostat.

15. The process of claim 1 further comprising the steps of:

determining if the current setpoint is within a predefined temperature range of the next scheduled setpoint; and

authorizing said step of changing the operative setpoint temperature of the thermostat by predefined amounts only when the current setpoint is outside the predefined temperature range.

16. A process for controlling the operative setpoint temperature of a thermostat when the currently scheduled setpoint temperature is to change to the next scheduled setpoint temperature at a predetermined time in the future said process comprising the steps of:

determining whether the thermostat is to operate on the basis of a first or second type of system for conditioning air being operatively connected to the thermostat;

determining when the current time is within a first predefined period of time of the next scheduled change time if the first type of heating or cooling system is indicated to be operatively connected to the thermostat;

determining when the current time is within a second predefined period of time of the next scheduled change time if the second type of heating or cooling system is indicated to be operatively connected to the thermostat;

changing the operative setpoint temperature of the thermostat by predefined amounts of temperature in calculated increments of time during the first predefined period of time if the first type of heating or cooling system is indicated to be operatively connected to the thermostat; and

changing the operative setpoint temperature of the thermostat by predefined amounts of temperature in calculated increments of time during the second predefined period of time if the second type of heating or cooling system is indicated to be operatively connected to the thermostat.

17. The process of claim 16 wherein said step of changing the operative setpoint temperature of the thermostat by predefined amounts of time during the first predefined period of time comprises the steps of:

dividing a portion of the first predefined period of time by the difference between the next scheduled setpoint and the currently scheduled setpoint so as to produce an increment of time that must elapse before each successive change in the operative setpoint temperature; and

changing the operative setpoint each time the calculated increment of time elapses.

18. The process of claim 17 wherein the portion of the first predefined period of time can be expressed as a fractional amount and wherein said step of changing the operative setpoint each time the calculated increment of time elapses comprises the step of:

changing the operative setpoint by a fraction of a temperature degree wherein the fraction of a temperature degree is equal to the fraction used in defining the fractional amount of the first period of time.

19. The process of claim 18 wherein said step of changing the operative setpoint temperature of the thermostat by predefined amounts of time during the second predefined period of time comprises the steps of:

dividing a portion of the second predefined period of time by the difference in the next scheduled setpoint and the currently scheduled setpoint so as to produce an increment of time that must elapse before each successive change in the setpoint temperature; and

changing the operative setpoint each time the calculated increment of time elapses.