Flow device and control system and methods for HVAC system monitoring

Patent metadata

Field	Value
Publication number	US-10976069-B2
Application number	US-201816230422-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Dec 29, 2017
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

Flow device systems for use in an HVAC system (“HVAC”) are described. The system may include a controller receiving sensor signals including differential pressure, valve commands, fan/pump speed, and fan/pump motor power signal from the HVAC. The controller transmits override valve commands for multiple valve positions of the valve and multiple speeds of the fan and pump. A characteristic curve may be determined from the signals provided from the HVAC and the measured flow rate at each valve position or fan/pump speed during transmission of the plurality of override valve commands for the valve positions of the valve and fan/pump speed for fan/pump operation frequencies. Virtual flow rate through the valve, fan or pump is determined using the characteristic curve. In addition, valve dynamic behavior is determined using valve stiction and valve stiction plus deadband. Valve commands are updated based on valve dynamic behavior and a valve characteristic curve.

First claim

What is claimed is:

1. A flow device system for use in a heating, ventilation and air conditioning (HVAC) system, comprising:
a controller having one or more non-transitory computer readable medium storing a set of computer executable instructions for running on one or more processors that when executed cause the one or more processors to:
receive a plurality of signals from the HVAC system, the signals providing differential pressure across a first valve, multiple valve positions for the first valve and associated valve commands for each of said multiple valve positions;
receive a measured flow rate at at least a subset of said multiple valve positions from a sensor;
transmit a plurality of override valve commands for the multiple valve positions of the first valve;
determine a valve characteristic curve based on the signals provided from the HVAC system and the measured flow rate at at least the subset of said multiple valve positions;
determine a virtual flow through the first valve using the valve characteristic curve;
determine a valve dynamic behavior using valve stiction and valve stiction plus deadband;
update the override valve commands based on the valve dynamic behavior and the valve characteristic curve to generate updated override valve commands; and,
transmit the updated override valve commands to a building automation system of the HVAC system.

2. The flow device system of claim 1 , further comprising one or more pressure sensors for providing the signals providing differential pressure.

3. The flow device system of claim 2 , wherein the differential pressure is a valve differential pressure.

4. The flow device system of claim 2 , wherein the differential pressure is a fan/pump differential pressure.

5. The flow device system of claim 1 , wherein the computer executable instructions further comprise an instruction to determine a stiction curve comparing the override valve commands to the multiple valve positions.

6. The flow device system of claim 5 , wherein determining the valve dynamic behavior using valve stiction and valve stiction plus deadband includes determining an average valve stiction and valve stiction plus deadband using the stiction curve comparing at least the subset of the override valve commands to the multiple valve positions.

7. The flow device system of claim 1 , wherein the measured flow rate includes a measured water flow, wherein determination of the valve characteristic curve further includes determining a correlation between determined values of the measured water flow and the differential pressure across the first valve at the multiple valve positions and actual valve positions, and regressing such correlation.

8. A flow device system for use in a heating, ventilation and air conditioning (HVAC) system, comprising:
a controller having one or more non-transitory computer readable medium storing a set of computer executable instructions for running on one or more processors that when executed cause the one or more processors to:
receive a plurality of signals, the signals providing motor input power of a first motor of a fan, a fan head, and a motor efficiency;
determine a virtual flow rate of air flowing through the HVAC system using the plurality of signals;
obtain an in-situ measured flow rate of air through a duct within the HVAC system, the in-situ measured flow rate of air being obtained by a measuring probe extending through a hole in an exterior wall of the duct, the measuring probe supported by a holding bracket connected to the exterior wall of the duct with duct grippers;
determine a fan characteristic model using the determined virtual flow rate and the in-situ measured flow rate through the HVAC system; and,
calibrate the fan using the fan characteristic model.

9. The flow device system of claim 8 , further comprising one or more pressure sensors for providing differential pressure signals.

10. The flow device system of claim 8 , wherein signals for power of the first motor are received directly from a motor control panel of the first motor.

11. The flow device system of claim 8 , wherein the virtual flow rate of air is determined by dividing a fan differential pressure by a product of motor input power, pump efficiency and motor efficiency.

12. A heating, ventilation and air conditioning (HVAC) system, comprising:
a controller having one or more non-transitory computer readable medium storing a set of computer executable instructions for running on one or more processors that when executed cause the one or more processors to:
receive a plurality of signals from the HVAC system, the signals providing differential pressure across a first valve, multiple valve positions for the first valve and associated valve commands for each of said multiple valve positions;
receive measured flow rate at at least a subset of said multiple valve positions from a sensor;
transmit a plurality of override valve commands for multiple valve positions of the first valve;
determine a valve characteristic curve based on the signals provided from the HVAC system and the measured flow rate at the at least the subset of said multiple valve positions;
determine virtual flow through the first valve using the valve characteristic curve;
determine valve dynamic behavior using valve stiction and valve stiction plus deadband;
update the override valve commands based on valve dynamic behavior and the valve characteristic curve to generate updated override valve commands; and,
transmit the updated override valve commands to a building automation system of the HVAC system.

13. The HVAC system of claim 12 , wherein the controller further comprises one or more pressure sensors for providing the signals providing differential pressure.

14. The HVAC system of claim 13 , wherein the differential pressure is a valve differential pressure.

15. The HVAC system of claim 13 , wherein the differential pressure is a fan/pump differential pressure.

16. A method comprising:
receiving a plurality of signals from a HVAC system, the signals providing differential pressure across a first valve, multiple valve positions for the first valve and associated valve commands for each of said multiple valve positions;
receiving measured flow rate at at least a subset of said multiple valve positions from at least one sensor;
transmitting a plurality of override valve commands for the multiple valve positions of the first valve;
determining a valve characteristic curve based on the signals provided from the HVAC system and the measured flow rate at the at least the subset of said multiple valve positions;
determining a virtual flow through the first valve using the valve characteristic curve;
determining a valve dynamic behavior using valve stiction and valve stiction plus deadband;
calibrating the override valve commands based on valve dynamic behavior and the valve characteristic curve to generate calibrated override valve commands; and,
transmit the calibrated override valve commands to a building automation system of the HVAC system, wherein at least one of said multiple valve positions is caused to be adjusted.

17. The method of claim 16 , further comprising outputting information associated with the calibrated override valve commands in a form perceivable by a user and/or operator of the HVAC system.

18. The method of claim 17 , wherein the information is output on a computer monitor, a screen, a touchscreen, a speaker, a website, a television set, an augmented reality system, a smart phone, a PDA, a cell phone, a fax machine

Assignees

• Univ Oklahoma

Inventors

• Song Li
• Wang Gang

Classifications

• F24F11/84

  using valves · CPC title

• F24F2140/10

  Pressure · CPC title

• F24F2140/12

  Heat-exchange fluid pressure · CPC title

• F24F2110/30

  Velocity · CPC title

• F24F11/49 Primary

  ensuring correct operation, e.g. by trial operation or configuration checks · CPC title