Temperature controller

• US 5,718,372 A
• Filed: 03/17/1997
• Issued: 02/17/1998
• Est. Priority Date: 03/17/1997
• Status: Expired due to Fees

• Current Assignee: Carl Tishler
• Original Assignee: Carl Tishler
• Inventors: Tishler, Carl
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US08/819,588
• Time in Patent Office: 337 Days
• Field of Search: 236/49.31 F, 165/240, 392/349
• US Class Current: 236/11
• CPC Class Codes: F24D 19/1084 for air heating systems
• 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 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: G05D 23/1917 using digital means

Abstract

A supplementary thermal system controller for assisting a main system controller in retaining a desired temperature rise by monitoring the temperature in the return duct, wherein the supplemental controller comprises a microcontroller for reading and processing return duct temperature measurements, a signal conditioner circuit for preparing temperature related signals for processing by the microcontroller, processor readable medium of program code for determining the rate of temperature change in the return duct and providing control signals based on the rate of temperature change, and a supplemental thermal source driver for controlling a supplemental thermal source, such as electrical resistance heating elements, to cause the assisting temperature source to increase or decrease its thermal output.

Claims

1. A supplementary thermal system controller for assisting a main air temperature control system in maintaining a desired air temperature in at least one zone by communicating with at least one corresponding temperature sensor, wherein the main air temperature control system includes a duct system having a supply duct and a return duct for routing the air medium through the zone and situating the temperature sensors, a circulation means for circulating air through the ducts, a supplemental thermal source, in thermal communication with said circulation means and the air medium, for providing a secondary thermal output to the air medium to assist in maintaining the desired air temperature and a thermostat responsive to the temperature of the circulated air so as to activate the main air temperature control system when the air temperature passes a predetermined desired temperature setpoint, said controller comprising:

(a) a microcontroller for reading and processing a processor readable medium of program code and being in electrical communication with the thermostat for being activated by the thermostat together with the main air temperature control system;

(b) a signal conditioner circuit in electrical communication with said microcontroller and at least one temperature sensor for receiving and electrically communicating temperature related signals generated by the temperature sensor with said microcontroller, said signals providing successive temperature measurements of the air medium in the return duct;

(c) processor readable medium of program code in electrical communication with said successive return duct temperature measurements, said program code comprising;

processing means for reading said return duct temperature measurements and determining the rate of temperature change of the air medium in the return duct from said successive return duct temperature measurements;

comparison means, in communication with said processing means, for comparing said successive return duct temperatures with predetermined thresholds; and

energizing means, in communication with said comparison means, for selectively generating control signals based on the relationship of the return duct temperature measurements to said thresholds to selectively energize the supplemental thermal source while the desired temperature is being achieved; and

(d) a supplemental thermal source driver, in electrical communication with said energizing means, for adjusting the secondary thermal output of the supplemental thermal source in response to said control signals.

2. A controller as recited in claim 1, wherein said processing means further comprises:

difference means for deriving a return duct temperature difference between said successive return duct temperature measurements over a predetermined period of time, said difference means being in communication with said comparison means for comparing said return duct temperature difference to selected predetermined thresholds.

3. A controller as recited in claim 1, wherein said energizing means further comprises:

a first control signal means for generating a first control signal that adjustably increases the secondary thermal output of the supplemental thermal source; and

a second control signal means for generating a second control signal that adjustably decreases the secondary thermal output of said supplemental thermal source.

4. A controller as recited in claim 1, wherein said signal conditioner circuit comprises:

an amplifier means for amplifying said return duct temperature related signals; and

an analog-to-digital converter for converting said return duct temperature related signals from analog to digital for communicating with said microcontroller.

5. A controller as recited in claim 1, wherein said signal conditioner circuit comprises:

a differential amplifier means, in electrical communication with the temperature sensors, for receiving said return duct temperature related signals at a first input and a constant voltage at a second input and producing an output proportional to the difference between said first and second inputs, said constant voltage corresponding to said predetermined thresholds.

6. A controller as recited in claim 1, wherein said differential amplifier means is designed to saturate when said return duct temperature related signal exceeds a predetermined voltage.

7. A controller as recited in claim 1, wherein said program code further comprises:

recall means, in electrical communication with said supplemental thermal source driver, for automatically setting said supplemental thermal source driver at a last known setting when starting said controller after a predetermined period of time so that the supplemental thermal source produces the last known secondary thermal output.

8. A controller as recited in claim 7, further comprising a memory means, in electrical communication with said microcontroller and said recall means, for selectively storing said return duct temperature measurements and said last known setting secondary thermal output.

9. A controller as recited in claim 1, further comprising at least one temperature sensor in electrical communication with said signal conditioning circuit.

10. A controller as recited in claim 1, further comprising a quick response switch for automatically setting said supplemental thermal source driver to a predetermined position that causes the supplemental thermal source to provide a predetermined amount of secondary thermal output.

11. A supplementary heating system controller for assisting a main heating system in maintaining a desired air temperature in at least one zone by communicating with at least one corresponding temperature sensor, wherein the main heating system includes a duct system having a supply duct and a return duct for routing the air medium through the zone and situating the temperature sensors, a circulation means for circulating air through the ducts, a supplemental heating source, in thermal communication with said circulation means and the air medium, for providing a secondary heating output into the air medium to assist in maintaining the desired air temperature and a thermostat responsive to the temperature of the circulated air so as to activate the main heating system when the air temperature falls below a predetermined desired temperature setpoint, said controller comprising:

(a) a microcontroller for reading and processing a processor readable medium of program code and being in electrical communication with the thermostat for being activated by the thermostat together with the main heating system;

(b) a signal conditioner circuit in electrical communication with said microcontroller and at least one temperature sensor for receiving and electrically communicating temperature related signals generated by the temperature sensor with said microcontroller, said signals providing successive temperature measurements of the air medium in the return duct;

(c) processor readable medium of program code in electrical communication with said successive return duct temperature measurements, said program code comprising;

processing means for reading said return duct temperature measurements and determining the rate of temperature change of the air medium in the return duct from said successive return duct temperature measurements;

comparison means, in communication with said processing means, for comparing said rate of temperature change with a high limit and a low limit; and

energizing means, in communication with said comparison means, for selectively generating a first control signal when the rate of temperature change falls below said low limit to selectively increase the secondary heating output of the supplemental heating source, and for selectively generating a second control signal when the rate of temperature change exceeds said high limit to selectively decrease the secondary heating output of the supplemental heating source; and

(d) a supplemental heating source driver, in electrical communication with said energizing means, for adjustably energizing and deenergizing the supplemental heating source in response to said control signals.

12. A controller as recited in claim 11, wherein said processing means further comprises:

difference means for determining the rate of temperature change by deriving a return duct temperature difference between said successive return duct temperature measurements over a predetermined period of time, said difference means being in communication with said comparison means for comparing said return duct temperature difference to said high limit and said low limit.

13. A controller as recited in claim 12, wherein said signal conditioner circuit comprises:

an amplifier means, electrically communicating said microcontroller with said return duct temperature related signals, for amplifying said return duct temperature related signals; and

an analog-to-digital converter, electrically communicating said amplifier means with said microcontroller, for converting said return duct temperature related signals from analog to digital for communicating with said microcontroller.

14. A controller as recited in claim 12, wherein said signal conditioner circuit comprises:

a differential amplifier means, in electrical communication with the temperature sensors, for receiving said return duct temperature related signals at a first input and a predetermined constant voltage at a second input and producing an output proportional to the difference between said first and second inputs.

15. A controller as recited in claim 14, wherein said program code further comprises:

bypass means, in electrical communication with said differential amplifier means, for bypassing said comparison means and said difference means and jumping to said energizing means when said return duct temperature measurement falls outside a predetermined window, said window having a low temperature threshold and a high temperature threshold, said constant voltage corresponding to said low temperature threshold, said energizing means generating said first control signal when said return duct temperature measurement falls below said low temperature threshold to increase the secondary heating output, and generating said second control signal when said return duct temperature measurement exceeds said high limit to decrease the secondary heating output.

16. A controller as recited in claim 15, further comprising at least one temperature sensor in electrical communication with said signal conditioning circuit.

17. A controller as recited in claim 16, wherein said supplemental heating source driver causes the supplemental heating source to increase resistance heating in response to said first control signal and decrease resistance heating in response to said second control signal when the supplemental heating source comprises an electrical resisting heating element assembly.

18. A controller as recited in claim 17, further comprising an electrical resistance heating assembly wherein the supplemental thermal source comprises said electrical resistance heating assembly.

19. A controller as recited in claim 15, wherein said differential amplifier means is designed to saturate when said return duct temperature related signal exceeds a predetermined voltage, said predetermined voltage corresponding to said high temperature threshold.

20. A controller as recited in claim 15, wherein said program code further comprises:

recall means, in electrical communication with said supplemental heating source driver, for automatically setting said supplemental heating source driver at a last known setting when predetermined conditions are satisfied so that the secondary heating output initially starts at the last known setting.

21. A controller as recited in claim 20, further comprising a memory means, in electrical communication with said microcontroller and said recall means, for selectively storing said return duct temperature measurements and said last known setting.

22. A controller as recited in claim 11, further comprising a quick response switch for automatically setting said supplemental thermal source driver to a maximum position that causes the supplemental heating source to provide a maximum secondary heating output.

23. A method for assisting a main heating system in maintaining a desired air temperature in at least one zone by communicating with at least one corresponding temperature sensor, wherein the main heating system includes a duct system having a supply duct and a return duct for routing the air medium through the zone and situating the temperature sensors, a circulation means for circulating air through the ducts, a supplemental heating source, in thermal communication with said circulation means and the air medium, for providing a secondary heating output to the air medium to assist in maintaining the desired air temperature and a thermostat responsive to the temperature of the circulated air so as to activate the main heating system when the air temperature falls below a predetermined desired temperature setpoint, said method comprising the steps of:

(a) measuring the temperature of the air medium in the return duct to derive a return duct temperature measurement;

(b) comparing said return duct temperature measurement to a low temperature threshold and a high temperature threshold;

(c) increasing the secondary heating output when said return duct temperature measurement falls below said low temperature threshold and decreasing said secondary heating output when said return duct temperature exceeds said high temperature threshold;

(d) deriving a difference between successive return duct temperature measurements when said return duct temperature measurement falls between said low temperature threshold and said high temperature threshold; and

(e) comparing said difference to a high limit and decreasing the secondary heating output when said difference exceeds said high limit, and comparing said difference to a low limit and increasing the secondary heating output when said difference falls below said low limit.

24. A method as recited in claim 23, further comprising the step of storing the secondary heating output.