Intelligent setpoint changeover for a programmable thermostat

• US 5,192,020 A
• Filed: 11/08/1991
• Issued: 03/09/1993
• Est. Priority Date: 11/08/1991
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Shah, Dipak J.
• Primary Examiner(s): Hepperle, Stephen M.
• Application Number:
  US07/789,503
• Time in Patent Office: 487 Days
• Field of Search: 236/46 R, 165/12, 62/231
• US Class Current: 236/46.00R
• 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 11/61 using timers
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: G05D 23/1904 variable in time
• CPC Class Codes: G05D 23/1919 characterised by the type of controller

Abstract

An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading the comfort level of the area of temperature modification. The apparatus prevents short-cycling of either a heating or a cooling system which can occur due to changes in the setpoint temperature. The apparatus operates by determining the length of time of "on" portion and"off" portion of the duty cycle of the air temperature conditioning plant. It then determines the time until the upcoming cycle of the temperature conditioning plant and either advances or delays the temperature changeover until the beginning of the upcoming "on" period or the upcoming "off" period of the upcoming duty cycle, or the last "on" period or the last "off" period of the last duty cycle of the air temperature conditioning plant.

Claims

1. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level comprising:

a programmable changeover thermostat;

an input means for programming said thermostat with changeover temperature settings at selectable time of day periods;

a clock means to determine time of day;

a timing means for determining the length of time of an "on" portion and an "off" portion of said duty cycle of said air temperature conditioning plant;

a comparison means to determine a time until an upcoming temperature conditioning plant cycle;

a means to advance or delay said temperature changeover until the beginning of the upcoming "on" period or upcoming "off" period of the upcoming duty cycle or the last "on" period or the last "off" period of the last duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle or less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

2. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover advances said temperature changeover by changing said changeover temperature setting to said upcoming changeover temperature setting until the upcoming time of day period for the upcoming changeover temperature setting when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

3. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover advances said temperature changeover by changing the upcoming pre-programmed temperature changeover setting time of day period to equal said time of day until the time of day equals said actual upcoming pre-programmed temperature changeover setting time of day when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

4. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover delays said temperature changeover by changing said upcoming changeover temperature setting to said current changeover temperature setting until the time of day equals the current time of day plus the length of time of an "on" portion of said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

5. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover delays said temperature changeover by changing said time of day for said upcoming changeover temperature setting to said current time of day plus said length of time of an "on " portion on said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

7. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover advances said temperature changeover by changing the upcoming pre-programmed temperature changeover setting time of day period to equal said time of day until the time of day equals said actual upcoming pre-programmed temperature changeover setting time of day when the time until the upcoming temperature changeover is less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

8. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover delays said temperature changeover by changing said upcoming changeover temperature setting to said current changeover temperature setting until the time of day equals the current time of day plus the length of time of an "off" portion of said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

9. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim 1, wherein said means to advance or delay said temperature changeover delays said temperature changeover by changing said time of day for said upcoming changeover temperature setting to said current time of day plus said length of time of an "off " portion on said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

6. An apparatus to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading comfort level of claim I, wherein said means to advance or delay said temperature changeover advances said temperature changeover by changing said changeover temperature setting to said upcoming changeover temperature setting until the time of day period equals the upcoming changeover time of day period when the time until the upcoming temperature changeover is less than the time of the last "off" period of said air temperature conditioning plant.

10. A method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level comprising the steps of:

presetting a programmable changeover thermostat with a sequence of changeover temperature and time of day settings for initiation of each changeover temperature;

determining the length of time of an "on" portion and an "off" portion of a duty cycle of said air temperature conditioning plant;

determining a time until an upcoming temperature conditioning plant cycle; and

advancing or delaying said temperature changeover until the beginning of the upcoming "on" period or upcoming "off" period of the upcoming duty cycle or the last "on" period or the last "off" period of the last duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle or less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

11. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, comprises the step of advancing said temperature changeover by changing said changeover temperature setting to said upcoming changeover temperature setting until the upcoming time of day period for the upcoming changeover temperature setting when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

12. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of advancing said temperature changeover by changing the upcoming pre-programmed temperature changeover setting time of day period to equal said time of day until the time of day equals said actual upcoming pre-programmed temperature changeover setting time of day when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

13. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of delaying said temperature changeover by changing said upcoming changeover temperature setting to said current changeover temperature setting until the time of day equals the current time of day plus the length of time of an "on" portion of said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

14. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of delaying said temperature changeover by changing said time of day for said upcoming changeover temperature setting to said current time of day plus said length of time of an "on " portion on said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "on" period duty cycle of said air temperature conditioning plant.

15. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of advancing said temperature changeover by changing said changeover temperature setting to said upcoming changeover temperature setting until time of day period equals the upcoming changeover time of day period the time until the upcoming temperature changeover is less than the time of the last "off" period of said air temperature conditioning plant.

16. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of advancing said temperature changeover by changing the upcoming pre-programmed temperature changeover setting time of day period to equal said time of day until the time of day equals said actual upcoming preprogrammed temperature changeover setting time of day when the time until the upcoming temperature changeover is less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

17. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of delaying said temperature changeover by changing said upcoming changeover temperature setting to said current changeover temperature setting until the time of day equals the current time of day plus the length of time of an "off" portion of said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "off" period duty cycle of said air temperature conditioning plant.

18. The method to match initiation of temperature changeover settings of a thermostat to a duty cycle of an air temperature conditioning plant without degrading occupant comfort level of claim 10, further comprises the step of delaying said temperature changeover by changing said time of day for said upcoming changeover temperature setting to said current time of day plus said length of time of an "off " portion on said duty cycle of said air temperature conditioning plant when the time until the upcoming temperature changeover is less than the time of the last "off" period duty cycle of said air temperature conditioning plant.