Building control system using a control device position as a proxy for static pressure in a conduit

Patent metadata

Field	Value
Publication number	US-11859848-B2
Application number	US-202117362466-A
Country	US
Kind code	B2
Filing date	Jun 29, 2021
Priority date	Jun 30, 2020
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

An environmental control system for a building is shown. The system includes a control device operable affect a static pressure in a conduit, a building device operable to affect a flow rate of a fluid through the conduit, and a controller including a processing circuit configured to perform a volumetric control process to generate a control signal for the drive device. The processing circuit is further configured to receive an operating position signal of the control device. The processing circuit is further configured to determine an estimated static pressure level within the duct using the operating position signal of the control device and update the control signal based on the estimated static pressure level determined using the operating position. The processing circuit is further configured to operate the drive device based on the updated control signal to affect the flow rate of the fluid.

First claim

What is claimed is:

1. An environmental control system for a building, the system comprising:
a control device operable to affect a static pressure within a conduit;
a building device operable to affect a flow rate of a fluid through the conduit, the building device comprising a drive device that affects operation of the building device; and
a controller comprising a processing circuit configured to:
perform a volumetric control process to generate a control signal for the drive device;
receive an operating position signal of the control device indicating a current position of the control device within the conduit;
determine an estimated static pressure level within the conduit using the current position of the control device within the conduit without requiring a measurement of the estimated static pressure level, wherein determining the estimated static pressure level comprises (i) determining a first estimated static pressure level when the control device is in a first position within the conduit without requiring a measurement of the first estimated static pressure level and (ii) determining a second estimated static pressure level different from the first estimated static pressure level when the control device is in a second position within the conduit different from the first position without requiring a measurement of the second estimated static pressure level, wherein at least one of the first position or the second position is an intermediate position between a fully open position and a fully closed position;
update the control signal based on the estimated static pressure level within the conduit determined using the current position of the control device within the conduit; and
operate the drive device based on the updated control signal to affect the flow rate of the fluid.

2. The system of claim 1 , wherein:
the control device is a damper of a variable air volume unit or a valve;
the building device is an air handling unit or a pump; and
the fluid is a gas or a liquid.

3. The system of claim 1 , wherein the updating of the control signal based on the estimated static pressure level within the conduit further comprises:
establishing a plurality of static pressure ranges based on a plurality of open control devices, the plurality of open control devices comprising the control device;
determining whether the received operating position signal is indicative of the control device being open;
associating the indication of the control device being open with one of the plurality of static pressure ranges in which the building device operates; and
adjusting the control signal based on the building device operating in the one of the plurality of static pressure ranges.

4. The system of claim 1 , wherein the updating of the control signal based on the estimated static pressure level within the conduit further comprises:
a plurality of static pressure ranges based on a plurality of open control devices, the plurality of open control devices comprising the control device;
determining a percentage to which the control device has been opened based on the received operating position signal;
associating the percentage to which the control device has been opened with one of the plurality of static pressure ranges in which the building device operates; and
adjusting the control signal based on the building device operating in the one of the plurality of static pressure ranges.

5. The system of claim 1 , wherein the processing circuit is further configured to:
perform a regression to identify a relationship between a low input/output (I/O) pair and a high I/O pair associated with the building device, wherein the low I/O pair and the high I/O pair describe a minimum value and a maximum value of the control signal for the building device; and
update the control signal based on the relationship.

6. The system of claim 1 , wherein the processing circuit is further configured to:
increase a setpoint associated with the estimated static pressure level within the conduit in response to determining that a number of control devices opened above a predefined threshold exceeds a maximum limit;
decrease the setpoint in response to determining that the number of control devices is below a minimum limit; and
maintain the setpoint in response to determining the number of control devices is between the minimum limit and the maximum limit;
wherein the control signal is updated further based on the setpoint.

7. The system of claim 6 , wherein the processing circuit is further configured to operate the control device based on the setpoint to affect the estimated static pressure level within the conduit, wherein the current position of the control device within the conduit acts as a proxy for the estimated static pressure level within the conduit.

8. The system of claim 1 , wherein:
the control signal indicates at least one of a frequency value or a voltage value; and
the drive device provides the at least one of the frequency value or the voltage value to a component of the building device to affect a rotational speed of the component.

9. A method for affecting a flow rate of a fluid through a conduit, the method comprising:
performing a volumetric control process to generate a control signal for a drive device of a building device, the building device operable to affect the flow rate of the fluid through the conduit;
receiving an operating position signal of a control device indicating a current position of the control device within the conduit;
determining an estimated static pressure level within the conduit using the current position of the control device within the conduit without requiring a measurement of the estimated static pressure level, wherein determining the estimated static pressure level comprises (i) determining a first estimated static pressure level when the control device is in a first position within the conduit without requiring a measurement of the first estimated static pressure level and (ii) determining a second estimated static pressure level different from the first estimated static pressure level when the control device is in a second position within the conduit different from the first position without requiring a measurement of the second estimated static pressure level, wherein at least one of the first position or the second position is an intermediate position between a fully open position and a fully closed position;
updating the control signal based on the estimated static pressure level within the conduit determined using the current position of the control device within the conduit; and
operating the drive device based on the updated control signal to affect the flow rate of the fluid.

10. The method of claim 9 , wherein:
the control device is a variable air volume damper or a valve;
the building device is an air handling unit or a pump; and
the fluid is a gas or a liquid.

11. The method of claim 9 , wherein the updating of the control signal based on the estimated static pressure level within the conduit further comprises:
establishing a plurality of static pressure ranges based on a plurality of open control devices, the plurality of open control devices comprising the control device;
determining whether the received operating position signal is indicative of the control device being open;
associating the indication of the control device being open with one of the plurality of static pressure ranges in which the building device operates; and
adjusting the control signal based on the building device operating in the one of the plurality of static pressure ranges.

12. The method of claim 9 , wherein the updati

Assignees

• Johnson Controls Tyco IP Holdings LLP

Inventors

• Chauhan Amit

Classifications

• F24F11/65 Primary

  for selecting an operating mode · CPC title

• F24F3/02

  characterised by the pressure or velocity of the primary air · CPC title

• F24F11/64

  using pre-stored data · CPC title

• F24F2140/10

  Pressure · CPC title

• F24F11/74 Primary

  for controlling air flow rate or air velocity · CPC title