Self-optimizing device for controlling a heating system

• US 6,409,090 B1
• Filed: 05/18/2000
• Issued: 06/25/2002
• Est. Priority Date: 05/18/2000
• Status: Expired due to Fees

• Current Assignee: Microtherm Inc.
• Original Assignee: Microtherm Inc.
• Inventors: Gilvar, David L., Harter, Steven P., Landry, Steven G.
• Primary Examiner(s): Joyce, Harold
• Assistant Examiner(s): BOLES, DEREK
• Application Number:
  US09/572,878
• Time in Patent Office: 768 Days
• Field of Search: 237/2.A, 237/8.A, 122/448.1, 236/46.R
• US Class Current: 237/2.00A
• CPC Class Codes: G05D 23/1923 using thermal energy, the cost of which varies in function of time

Abstract

A self optimizing device for controlling a heating unit in a manner so as to improve the energy efficiency of the heating unit using an autocalibration processor. The heating unit employs a heating medium that is heated by the heating unit and which transfers the heat into an ambient atmosphere outside of the heating unit. The heating unit has an on-state initiated when a characteristic of the heating medium representative of the heating capacity of the medium decreases below a minimum level, and an off-state initiated when the characteristic of the heating medium reaches a maximum level. The controller includes an input element, an output element, a time-measuring element, and a processor. The input element receives a signal from a sensor, the signal indicating the heating medium characteristic representative of the heating capacity of the heating medium. The output element signals the heating unit to begin its on-state. The time-measuring element measures an off-time, the off-time being the length of time from initiation of the off-state of the heating unit until the characteristic of the heating medium decreases below the minimum level. The processor determines a delay time and for signaling the heating unit to delay initiation of the on-state by the delay time amount, the extension of the off-time resulting in an energy savings over an undelayed initiation. The processor further comprising an autocalibration processor for determining a delay time that results in optimum energy savings.

Claims

1. An apparatus for controlling a heating unit, the heating unit employing a heating medium that is heated by the heating unit and which transfers heat into an ambient atmosphere outside of the heating unit, the heating unit having an on-state initiated when a characteristic of the heating medium representative of the heating capacity of the medium decreases below a minimum level, and an off-state initiated when the characteristic of the heating medium reaches a maximum level, the apparatus comprising:

an input element for receiving a signal from a sensor, the signal indicating the heating medium characteristic representative of the heating capacity of the heating medium;

an output element for signaling the heating unit to begin its on-state;

a time-measuring element for measuring an off-time, the off-time being the length of time from initiation of the off-state of the heating unit until the characteristic of the heating medium decreases below the minimum level; and

a processor for determining a delay time and for signaling the heating unit to delay initiation of the on-state by the delay time amount, the delay resulting in an energy savings over an undelayed initiation, the processor further comprising an autocalibration processor which tests at least one delay time and calculates an energy savings index for each delay time tested, then calculates an optimum energy savings delay time.

2. The apparatus of claim 1, wherein the delay time is calculated as a function of the off-time.

3. The apparatus of claim 1, wherein the heating medium characteristic is selected from the group consisting of temperature and pressure.

4. The apparatus of claim 1, wherein the autocalibration processor calculates and tests a plurality of delay times and calculates and energy savings index for each delay time tested, then calculates an optimum energy savings delay time.

5. The apparatus of claim 1, wherein the autocalibration processor includes control logic for performing the steps of:

measuring on-time and off-time components of a first on-off cycle of the heating unit,

selecting a second on-off cycle for the heating unit, the second on-off cycle having an off-time similar to the off-time of the first on-off cycle of the heating unit;

applying a first delay time prior to initiating a subsequent on-state;

calculating an index corresponding to an energy savings for the first delay time;

selecting a third on-off cycle for the heating unit, the third on-off cycle having an off-time similar to the off-time of the first on-off cycle of the heating unit;

applying a second delay time prior to initiating a subsequent on-state;

calculating an index corresponding to an energy savings for the second delay time; and

calculating a delay time having an optimum energy savings index.

6. The apparatus of claim 5, wherein the off-time for each of the second and third on-off cycle is within about 15% of the length of the off-time of the first on-off cycle.

7. The apparatus of claim 5, wherein the delay time having an optimum energy savings index is calculated by selecting the off-time having the highest index.

8. The apparatus of claim 5, wherein the delay time having an optimum energy savings index is calculated by interpolation.

9. The apparatus of claim 1, wherein the calculation of an energy savings index comprises the steps of:

adding the on-time and off-time components for the on-off cycle to determine a total on-off time component;

selecting a predetermined time period;

dividing the predetermined time period by the total on-off time component to determine a total number of on-off cycles that would occur during the predetermined time period; and

multiplying the total number of on-off cycles by the on-time component to determine how long the heating unit would be in an on-state during the predetermined time period.

10. The apparatus of claim 1, wherein the apparatus is sized so as to be suitable for containment within a standard electrical junction box.

11. The apparatus of claim 1, wherein the apparatus is operable from a user interface associated with the processor.

12. The apparatus of claim 11, wherein the apparatus is operable from a computer network connected to the processor by a computer communication means.

13. An apparatus for controlling a heating unit, the heating unit employing a heating medium that is heated by the heating unit and which transfers heat into an ambient atmosphere outside of the heating unit, the heating unit having an on-state initiated when a characteristic of the heating medium representative of the heating capacity of the medium decreases below a minimum level, and an off-state initiated when the characteristic of the heating medium reaches a maximum level, the apparatus comprising:

an input element for receiving a signal from a sensor, the signal indicating the heating medium characteristic representative of the heating capacity of the heating medium;

an output element for signaling the heating unit to begin its on-state;

a time-measuring element for measuring an off-time, the off-time being the length of time from initiation of the off-state of the heating unit until the characteristic of the heating medium decreases below the minimum level; and

a processor for determining a delay time and for signaling the heating unit to delay initiation of the on-state by the delay time amount, the delay resulting in an energy savings over an undelayed initiation, the processor further comprising an autocalibration processor wherein the autocalibration processor is responsive to a thermal load on the heating unit to continuously calculate and apply a delay time that results in optimum energy savings, wherein a parameter corresponding to a thermal load is recorded comprising a moving average percentage of the thermal load over time as a function of burner on-time.

14. The apparatus of claim 13, wherein the moving average is taken over a period between 24 hours and one season.

15. The apparatus of claim 13, wherein the autocalibration processor includes control logic for performing the steps of:

selecting an initial economy factor for the processor;

recording a parameter of the heating system corresponding to a thermal load on the system;

calculating an optimum economy factor based on the parameter; and

incrementing or decrementing the processor economy factor in a direction toward the optimum economy factor.

16. The apparatus of claim 15, wherein the optimum economy factor is calculated as E−

(A×

(E÷

B));

where E is the maximum allowed economy factor, A is the parameter of the heating system corresponding to the thermal load on the system, and B is a maximum parameter of the heating system corresponding to the thermal load of the system.

17. The apparatus of claim 16, wherein A is a moving average.

18. An apparatus for controlling a heat transfer unit, the heat transfer unit employing a thermal medium whose thermal energy is affected by the heat transfer unit and which exchanges heat with an ambient atmosphere outside of the heat transfer unit, the apparatus comprising:

an input means for receiving a signal from a sensor, the signal indicating a thermal characteristic of the thermal medium;

a processor means for initiating an on-state and an off-state of the heat transfer unit based on the signal indicating a thermal characteristic of the thermal medium, the processor including;

a delay calculating means for calculating a delay time based on an economy factor for delaying the initiation of the on-state of the heat transfer unit; and

an autocalibration means for calculating an optimum economy factor applying the optimum economy factor to the delay calculating means, wherein the optimum economy factor comprises testing at least one delay time and determining an energy savings index for each delay time tested.

19. The apparatus of claim 18, wherein the heat transfer unit is an air conditioning unit.

20. The apparatus of claim 18, wherein the apparatus is operable from a user interface associated with the processor.

21. The apparatus of claim 18, wherein the apparatus is operable from a computer network connected to the processor by a computer communication means.

22. In a heating system employing a heating unit and a heating medium that is heated by a heating unit and which transfers heat into an ambient atmosphere outside of the heating system, the heating unit having an on-state initiated when a characteristic of the heating medium representative of the heating capacity of the medium decreases below a minimum level, and an off-state initiated when the characteristic of the heating medium reaches a maximum level, the heating system further comprising an input element for receiving a signal from a sensor, the signal indicating the heating medium characteristic representative of the heating capacity of the heating medium;

an output element for signaling the heating unit to begin its on-state;

a time-measuring element for measuring an off-time, the off-time being the length of time from initiation of the off-state of the heating unit until the characteristic of the heating medium decreases below the minimum level; and

a processor for determining a delay time based on an economy factor and for signaling the heating unit to delay initiation of the on-state by the delay time amount, the delay resulting in an energy savings over an undelayed initiation, the processor further comprising an autocalibration processor;

a method for operating at optimum efficiency comprising the steps of;

selecting an initial economy factor for the processor;

recording a parameter of the heating system corresponding to a moving average of the thermal load on the system taken over a period between 24 hours and one season;

calculating an optimum economy factor based on the parameter; and

incrementing or decrementing the processor economy factor in a direction toward the optimum economy factor.

23. The method of claim 22, wherein the parameter corresponding to the thermal load is a burner on-time percentage.

24. The method of claim 22, wherein the optimum economy factor is calculated as E−

(A×

(E÷

B));

where E is the maximum allowed economy factor, A is the parameter of the heating system corresponding to the thermal load on the system, and B is a maximum parameter of the heating system corresponding to the thermal load of the system.