Adaptive optimization for dynamic room pressurization control

• US 10,352,578 B2
• Filed: 06/06/2017
• Issued: 07/16/2019
• Est. Priority Date: 06/09/2016
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Adkerson, Curtis D.
• Primary Examiner(s): McAllister, Steven B
• Assistant Examiner(s): Probst, Samantha A
• Application Number:
  US15/615,383
• Publication Number:
  US 20170356666A1
• Time in Patent Office: 770 Days
• Field of Search: 454255
• CPC Class Codes: F24F 11/0001 for ventilation F24F11/30 takes precedence
• 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 11/64 using pre-stored data
• CPC Class Codes: F24F 11/65 for selecting an operating mode
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: G01N 1/26 with provision for intake from several spaces
• CPC Class Codes: G05D 16/028 Controlling a pressure difference control of flow G05D7/00
• CPC Class Codes: G05D 16/2073 with a plurality of pressure sources
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

An apparatus and method controls an environmental control system to maintain a differential pressure between a room and one or more adjacent areas by (1) determining a differential pressure error based on the differential pressure and a differential pressure set point using a proportional-integral-derivative (PID) controller; (2) increasing an air change per hour set point whenever one or more first parameters are satisfied; (3) decreasing the air change per hour set point whenever one or more second parameters are satisfied; and (4) sending one or more control signals to the environmental control system that maintain the differential pressure between the room and the one or more adjacent areas by adjusting: (a) the leading airflow to be approximately equal to the air flow change set point multiplied by a volume of the room divided by 60, and (b) the tracking airflow to maintain a volume differential set point.

Claims

1. A method for controlling an environmental control system to maintain a differential pressure between a room and one or more adjacent areas, comprising the steps of:

monitoring a temperature in the room, the differential pressure, a leading airflow for the room and a tracking airflow for the room;

determining a differential pressure error based on the differential pressure and a differential pressure set point using a proportional-integral-derivative (PID) controller;

increasing an air change per hour set point whenever;

(a) the temperature exceeds a high temperature threshold, (b) the temperature falls below a low temperature threshold and the environmental control system is operating at approximately 100% of heating capacity, or (c) the differential pressure error is greater than a first percentage of a maximum delta between the leading airflow and the tracking airflow;

decreasing the air change per hour set point whenever the differential pressure error is less than a second percentage of the maximum delta between the leading airflow and the tracking airflow, and the temperature is above the low temperature threshold and below the high temperature threshold; and

sending one or more control signals to the environmental control system that maintain the differential pressure between the room and the one or more adjacent areas by adjusting;

(a) the leading airflow to be approximately equal to the air flow change set point multiplied by a volume of the room divided by 60, and (b) the tracking airflow to maintain a volume differential set point.

2. The method of claim 1, further comprising the step of obtaining the volume of the room, the high temperature threshold, the low temperature threshold, the differential pressure set point, the air change per hour set point, the volume differential set point and the maximum delta between the leading airflow and the tracking airflow.

3. The method of claim 1, wherein:

the step of increasing the air change per hour set point is not performed if the increased air change per hour set point would exceed a maximum air change per hour set point; and

the step of decreasing the air change per hour set point is not performed if the decreased air change per hour set point would be below a minimum air change per hour set point.

4. The method of claim 3, further comprising the step of obtaining the minimum air change per hour set point and the maximum air change per hour set point.

5. The method of claim 3, wherein the maximum air change per hour comprises a first maximum air change per hour when the environmental control system is in a heating mode and a second maximum air change per hour when the environmental control system is in a cooling mode, wherein the first maximum air change per hour is less than the second maximum air change per hour.

6. The method of claim 5, further comprising the step of obtaining the first maximum air change per hour and the second maximum air change per hour.

7. The method as recited in claim 1, wherein:

the first percentage is approximately 97%; and

the second percentage is approximately 93%.

8. The method as recited in claim 1, further comprising the step of changing the high temperature threshold, the low temperature threshold, the differential pressure set point, the air change per hour set point, the volume differential set point, the maximum delta between the leading airflow and the tracking airflow, the first percentage or the second percentage.

9. The method of claim 1, further comprising:

monitoring a humidity in the room;

increasing the air change per hour set point whenever the humidity exceeds a high humidity threshold; and

wherein the step of decreasing the air change per hour set point comprise decreasing the air change per hour set point whenever the differential pressure error is less than a second percentage of the maximum delta between the leading airflow and the tracking airflow, and the temperature is above the low temperature threshold and below the high temperature, and the humidity is below the high humidity threshold.

10. The method of claim 9, further comprising the step of obtaining the high humidity threshold.

11. An apparatus for controlling an environmental control system to maintain a differential pressure between a room and one or more adjacent areas, comprising:

a communications interface;

a memory; and

a processor communicably coupled to the communications interface and the memory, wherein the processor (1) receives a temperature in the room, the differential pressure, a leading airflow for the room and a tracking airflow for the room via the communications interface, (2) determines a differential pressure error based on the differential pressure and a differential pressure set point using a proportional-integral-derivative (PID) algorithm, (3) increases an air change per hour set point whenever;

(a) the temperature exceeds a high temperature threshold, (b) the temperature falls below a low temperature threshold and the environmental control system is operating at approximately 100% of heating capacity, or (c) the differential pressure error is greater than a first percentage of a maximum delta between the leading airflow and the tracking airflow, (4) decreases the air change per hour set point whenever the differential pressure error is less than a second percentage of the maximum delta between the leading airflow and the tracking airflow, and the temperature is above the low temperature threshold and below the high temperature threshold, and (5) sends one or more control signals to the environmental control system via the communications interface that maintain the differential pressure between the room and the one or more adjacent areas by adjusting;

(a) the leading airflow to be approximately equal to the air flow change set point multiplied by a volume of the room divided by 60, and (b) the tracking airflow to maintain a volume differential set point.

12. The apparatus of claim 11, wherein the processor further obtains the volume of the room, the high temperature threshold, the low temperature threshold, the differential pressure set point, the air change per hour set point, the volume differential set point and the maximum delta between the leading airflow and the tracking airflow from the memory.

13. The apparatus of claim 11, wherein:

the processor does not increase the air change per hour set point when the increased air change per hour set point would exceed a maximum air change per hour set point; and

the processor does not decrease the air change per hour set point when the decreased air change per hour set point would be below a minimum air change per hour set point.

14. The apparatus of claim 13, wherein the processor further obtains the minimum air change per hour set point and the maximum air change per hour set point from the memory.

15. The apparatus of claim 13, wherein the maximum air change per hour comprises a first maximum air change per hour when the environmental control system is in a heating mode and a second maximum air change per hour when the environmental control system is in a cooling mode, wherein the first maximum air change per hour is less than the second maximum air change per hour.

16. The apparatus of claim 15, wherein the processor further obtains the first maximum air change per hour and the second maximum air change per hour from the memory.

17. The apparatus as recited in claim 11, wherein:

the first percentage is approximately 97%; and

the second percentage is approximately 93%.

18. The apparatus as recited in claim 11, wherein the processor further receives a change to the high temperature threshold, the low temperature threshold, the differential pressure set point, the air change per hour set point, the volume differential set point, the maximum delta between the leading airflow and the tracking airflow, the first percentage or the second percentage via the communications interface.

19. The apparatus of claim 11, wherein the processor further receives a humidity in the room via the communications interface, increases the air change per hour set point whenever the humidity exceeds a high humidity threshold, and decreases the air change per hour set point whenever the differential pressure error is less than a second percentage of the maximum delta between the leading airflow and the tracking airflow, and the temperature is above the low temperature threshold and below the high temperature, and the humidity is below the high humidity threshold.

20. The apparatus of claim 19, wherein the processor further obtains the high humidity threshold from the memory.