HVAC system with automated flow direction detection

Patent metadata

Field	Value
Publication number	US-9952074-B2
Application number	US-201615349979-A
Country	US
Kind code	B2
Filing date	Nov 11, 2016
Priority date	Nov 2, 2012
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A heating, ventilation, or air conditioning (HVAC) system with automated flow direction detection is provided. The HVAC system includes one or more hoses configured to provide airflow from HVAC equipment, a bidirectional pressure sensor coupled to the hoses, and a controller coupled to the bidirectional pressure sensor. The controller is configured to receive a signal from the bidirectional pressure sensor, determine a direction of the airflow relative to the bidirectional pressure sensor based on the signal, correct the signal for a reversed hose polarity relative to the bidirectional sensor based on the direction of the airflow, and perform a control activity using the corrected signal.

First claim

What is claimed is:

1. A heating, ventilation, or air conditioning (HVAC) system with automated flow direction detection, the HVAC system comprising:
one or more hoses configured to provide airflow from HVAC equipment;
a bidirectional pressure sensor coupled to the hoses; and
a controller coupled to the bidirectional pressure sensor, wherein the controller is configured to:
generate a dynamic threshold based on one or more past pressure values measured by the bidirectional pressure sensor;
receive a signal from the bidirectional pressure sensor, the signal comprising a current pressure value measured by the same bidirectional pressure sensor;
determine a direction of the airflow relative to the bidirectional pressure sensor by comparing the current pressure value to the dynamic threshold, wherein the controller assigns a first flow direction to the airflow in response to a determination that the current pressure value is greater than the dynamic threshold, and assigns a second flow direction to the airflow in response to a determination that the current pressure value is less than the dynamic threshold;
correct the signal for a reversed hose polarity relative to the bidirectional pressure sensor based on the direction of the airflow; and
perform a control activity using the corrected signal.

2. The HVAC system of claim 1 , wherein the bidirectional pressure sensor is configured to measure pressure values over time and provide a plurality of pressure values to the controller.

3. The HVAC system of claim 1 , wherein the past pressure values comprise multiple past pressure values, wherein the controller is configured to:
calculate a range of the past pressure values measured by the bidirectional pressure sensor;
compare the current pressure value measured by the bidirectional pressure sensor to the range of past pressure values; and
determine the direction of the airflow based on the current pressure value relative to the range of past pressure values.

4. The HVAC system of claim 3 , wherein the controller is configured to:
assign the first flow direction to the airflow in response to a determination that the current pressure value is greater than the range of past pressure values; and
assign the second flow direction to the airflow in response to a determination that the current pressure value is less than the range of past pressure values.

5. The HVAC system of claim 1 , wherein the past pressure values comprise multiple past pressure values, wherein the controller is configured to:
identify a threshold range for the past pressure values measured by the bidirectional pressure sensor, the threshold range spanning from a negative threshold value to a positive threshold value;
compare the current pressure value measured by the bidirectional pressure sensor to the threshold range; and
determine the direction of the airflow based on the current pressure value relative to the threshold range.

6. The HVAC system of claim 5 , wherein the controller is configured to:
assign the first flow direction to the airflow in response to a determination that the current pressure value is greater than the positive threshold value; and
assign the second flow direction to the airflow in response to a determination that the current pressure value is less than the negative threshold value.

7. The HVAC system of claim 5 , wherein the controller is configured to dynamically expand the threshold range by adjusting at least one of the negative threshold value and the positive threshold value in response to a determination that the current pressure value is outside the threshold range.

8. The HVAC system of claim 5 , wherein the controller is configured to dynamically collapse the threshold range by adjusting at least one of the negative threshold value and the positive threshold value in response to a determination that the current pressure value is within a predetermined interval between the negative threshold value and the positive threshold value.

9. The HVAC system of claim 8 , wherein the predetermined interval spans from a first interval value to a second interval value;
wherein the controller is configured to set the first interval value equal to a percentage of the negative threshold value and set the second interval value equal to a percentage of the positive threshold value.

10. The HVAC system of claim 8 , wherein dynamically collapsing the threshold range comprises:
setting the positive threshold value equal to a positive multiple of the current pressure value; and
setting the negative threshold value equal to a negative multiple of the current pressure value.

11. A method for automatically detecting flow direction in a heating, ventilation, or air conditioning (HVAC) system, the method comprising:
providing airflow from HVAC equipment via one or more hoses;
measuring pressure values with a bidirectional pressure sensor coupled to the hoses, the pressure values comprising one or more past pressure values measured by the bidirectional pressure sensor and a current pressure value measured by the same bidirectional pressure sensor;
generating a dynamic threshold based on the one or more past pressure values measured by the bidirectional pressure sensor;
determining a direction of the airflow relative to the bidirectional pressure sensor by:
comparing the current pressure value to the dynamic threshold;
assigning a first flow direction to the airflow in response to a determination that the current pressure value is greater than the dynamic threshold; and
assigning a second flow direction to the airflow in response to a determination that the current pressure value is less than the dynamic threshold;

correcting the current pressure value for a reversed hose polarity relative to the bidirectional pressure sensor based on the direction of the airflow; and
performing a control activity using the corrected current pressure value.

12. The method of claim 11 , wherein measuring the pressure values comprises measuring a plurality of pressure values over time;
the method further comprising providing the plurality of pressure values to a controller.

13. The method of claim 11 , wherein the past pressure values comprise multiple past pressure values, the method further comprising:
calculating a range of the past pressure values measured by the bidirectional pressure sensor;
comparing the current pressure value measured by the bidirectional pressure sensor to the range of past pressure values; and
determining the direction of the airflow based on the current pressure value relative to the range of past pressure values.

14. The method of claim 13 , further comprising:
assigning the first flow direction to the airflow in response to a determination that the current pressure value is greater than the range of past pressure values; and
assigning the second flow direction to the airflow in response to a determination that the current pressure value is less than the range of past pressure values.

15. The method of claim 11 , wherein the past pressure values comprise multiple past pressure values, the method further comprising:
identifying a threshold range for the past pressure values measured by the bidirectional pressure sensor, the threshold range spanning from a negative threshold value to a positive threshold value;
comparing the current pressure value measured by the bidirectional pressure sensor to the threshold range; and
determining the direction of the airflow based on the current pressure value relative to the threshold range.

16. The method of claim 15 , further

Assignees

• Johnson Controls Tech Co

Inventors

• Freund Mark G
• Goldschmidt Troy A
• Gavin Gary W
• Sloat Brandon A
• Gamroth Timothy C

Classifications

• F24F11/04

  Mechanical Engineering · mapped topic

• Y10T137/7722

  Line condition change responsive valves · CPC title

• F24F2011/0042

  Mechanical Engineering · mapped topic

• G01F1/34 Primary

  by measuring pressure or differential pressure · CPC title

• F24F11/755

  for cyclical variation of air flow rate or air velocity · CPC title