Duty-cycle controlling thermostat construction, system utilizing the same and method of making the same

• US 4,753,388 A
• Filed: 07/24/1987
• Issued: 06/28/1988
• Est. Priority Date: 07/24/1987
• Status: Expired due to Fees

• Current Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Original Assignee: Robertshaw Controls Company (Schneider Electric SE)
• Inventors: Rummage, Kenneth L.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/077,375
• Time in Patent Office: 340 Days
• Field of Search: 62/231, 165/12, 236/46 R, 236/78 D
• US Class Current: 236/46.00R
• CPC Class Codes: F23N 2223/08 Microprocessor; Microcomputer
• CPC Class Codes: F23N 5/203 using electronic means
• CPC Class Codes: G05D 23/1913 delivering a series of pulses
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

A thermostat construction for controlling the output effect of a heat exchanger means, a system utilizing such a construction and a method of making such a construction are provided, the thermostat construction having a unit for sensing room temperature that is the result of the output effect, having a set-point unit for selecting a desired room temperature to be provided by the heat exchanger, having a changing unit for changing the effective set-point setting of the set-point unit to change the duty-cycle of the heat exchanger, and having a unit for sensing the current duty-cycle of the heat exchanger and for causing the changing unit to change the effective set-point setting to a different temperature setting thereof as the duty-cycle approaches a peak duty-cycle of the heat exchanger so that the current duty-cycles is reduced.

Claims

1. In a thermostat construction for controlling the output temperature effect of a heat exchanger means, said thermostat construction having means for sensing room temperature that is the result of said output effect, said thermostat construction having a set-point means for selecting a desired room temperature to be provided by said heat exchanger means, said thermostat construction having changing means for changing the effective set-point setting of said set-point means to change the duty-cycle of said heat exchanger means, the improvement wherein said thermostat construction has means for sensing the current duty-cycle of said heat exchanger means and for causing said changing means to change said effective set-point setting to a different temperature setting thereof as said duty-cycle approaches a peak duty-cycle of said heat exchanger means so that said current duty-cycle is reduced.

2. A thermostat construction as set forth in claim 1 wherein said means for sensing the current duty-cycle of said heat exchanger means and for causing said changing means to change said effective set-point setting comprises a microprocessor.

3. A thermostat construction set forth in claim 2 wherein said thermostat construction has timing means for supplying time thereto.

4. A thermostat construction as set forth in claim 3 wherein said microprocessor has means for measuring said current duty-cycle of said heat exchanger means at the end of each cycle of operation thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, said microprocessor having means for combining such integrated error to the current set-point temperature to change the same and provide said different temperature setting thereof.

5. A thermostat construction as set forth in claim 4 wherein said reference duty-cycle is a fixed number that is smaller than 100%.

6. A thermostat construction as set forth in claim 5 wherein said fixed number is in the range of approximately 40% to approximately 60%.

7. A thermostat construction as set forth in claim 3 wherein said heat exchanger means comprises an air conditioner means and wherein said microprocessor has means for measuring said current duty-cycle of said air conditioner means at the end of each cooling cycle thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, said microprocessor having means for adding such integrated error to the current set-point temperature to change the same and provide said different temperature setting thereof as a higher temperature setting thereof.

8. A thermostat construction as set forth in claim 3 wherein said heat exchanger means comprises a heating means and wherein said microprocessor has means for measuring said current duty-cycle of said heating means at the end of each heating cycle thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, said microprocessor having means for subtracting such integrated error from the current set-point temperature to change the same and provide said different temperature setting thereof as a lower temperature setting thereof.

9. In a system for controlling the output temperature effect of a heat exchanger means, said system having means for sensing room temperature that is the result of said output effect, said system having a set-point means for selecting a desired room temperature to be provided by said heat exchanger means, said system having changing means for changing the effective set-point setting of said set-point means to change the duty-cycle of said heat exchanger means, the improvement wherein said system has means for sensing the current duty-cycle of said heat exchanger and for causing said changing means to change said effective set-point setting to a different temperature setting thereof as said duty-cycle approaches a peak duty-cycle of said heat exchanger means so that said current duty-cycle is reduced.

10. A system as set forth in claim 9 wherein said means for sensing the current duty-cycle of said heat exchanger means and for causing said changing means to change said effective set-point setting comprises a microprocessor.

11. A system as set forth in claim 10 wherein said system has timing means for supplying time thereto.

12. A system as set forth in claim 9 wherein said microprocessor has means for measuring said current duty-cycle of said heat exchanger means at the end of each cycle of operation thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, said microprocessor having means for combining such integrated error to the current set-point temperature to change the same and provide said different temperature setting thereof.

13. A system as set forth in claim 12 wherein said reference duty-cycle is a fixed number that is smaller than 100%.

14. A system as set forth in claim 13 wherein said fixed number is in the range of approximately 40% to approximately 60%.

15. A system as set forth in claim 9 wherein said heat exchanger means comprises an air-conditioner means and wherein said microprocessor has means for measuring said current duty-cycle of said air-conditioner means at the end of each cooling cycle thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, said microprocessor having means for adding such integrated error to the current set-point temperature to change the same and provide said different temperature setting thereof as a higher temperature setting thereof.

16. A system as set forth in claim 9 wherein said heat exchanger means comprises a heating means and wherein said microprocessor has means for measuring said current duty-cycle of said heating means at the end of each heating cycle thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, said microprocessor having means for subtracting such integrated error from the current set-point temperature to change the same and provide said different temperature setting thereof as a lower temperature setting thereof.

17. In a method of making a thermostat construction for controlling the output temperature effect of a heat exchanger means, said thermostat construction having means for sensing room temperature that is the result of said output effect, said thermostat construction having a set-point means for selecting a desired room temperature to be provided by said heat exchanger means, said thermostat construction having changing means for changing the effective set-point setting of said set-point means to change the duty-cycle of said heat exchanger means, the improvement comprising the step of forming said thermostat construction with means for sensing the current duty-cycle of said heat exchanger means and for causing said changing means to change said effective set-point setting to a different temperature setting thereof as said duty-cycle approaches a peak duty-cycle of said heat exchanger means whereby said current duty-cycle is reduced.

18. A method of making a thermostat construction as set forth in claim 17 and including the step of forming said means for sensing the current duty-cycle of said heat exchanger means and for causing said changing means to change said effective set-point setting to comprise a microprocessor.

19. A method of making a thermostat construction as set forth in claim 18 and including the step of forming said thermostat construction to have timing means for supplying time thereto.

20. A method of making a thermostat construction as set forth in claim 19 and including the steps of forming said microprocessor with means for measuring said current duty-cycle of said heat exchanger means at the end of each cycle of operation thereof and compare the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, and forming said microprocessor with means for combining such integrated error to the current set-point temperature to change the same and provide said different temperature setting thereof.

21. A method of making a thermostat construction as set forth in claim 20 wherein said reference duty-cycle is a fixed number, that is smaller than 100%.

22. A method of making a thermostat construction as set forth in claim 21 wherein said fixed number is in the range of approximately 40% to approximately 60%.

23. A method of making a thermostat construction as set forth in claim 19 and including the steps of forming said exchanger means to comprise an air-conditioner means, forming said microprocessor with means for measuring said current duty-cycle of said air-conditioner means at the end of each cooling cycle thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, and forming said microprocessor with means for adding such integrated error to the current set-point temperature to change the same and provide said different temperature setting thereof as a higher temperature setting thereof.

24. A method of making a thermostat construction as set forth in claim 19 and including the steps of forming said exchanger means to comprise a heating means, forming said microprocessor with means for measuring said current duty-cycle of said heating means at the end of each heating cycle thereof and comparing the same to a control reference duty-cycle with the difference term thereof being integrated with respect to time to produce an integrated error, and forming said microprocessor with means for subtracting such integrated error from the current set-point temperature to change the same and provide said different temperature setting thereof as a lower temperature setting thereof.