Method and apparatus for balancing an air distribution system

• US 5,786,525 A
• Filed: 04/09/1996
• Issued: 07/28/1998
• Est. Priority Date: 04/09/1996
• Status: Expired due to Fees

• Current Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: Johnson Service Company
• Inventors: Freund, Mark G., Schram, Ronald
• Primary Examiner(s): Dombroske, George M.
• Application Number:
  US08/629,607
• Time in Patent Office: 840 Days
• Field of Search: 73/3, 73/118.2, 73/714, 73/722, 73/861.04, 73/861.66, 73/861.78, 236/49.1, 236/49.3, 236/49.4, 236/49.5
• US Class Current: 73/1.34
• 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 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: F24F 2110/00 Control inputs relating to air properties
• CPC Class Codes: F24F 3/044 Systems in which all treatment is given in the central station, i.e. all-air systems

Abstract

A flow measurement device and a VAV device are adapted to be directly coupled. The flow measurement device is adapted to automatically make and record flow measurements and to communicate the measurements to a VAV controller. The VAV controller is adapted to receive the flow measurements and self calibrate in response thereto. The VAV device is further adapted to report results of the calibration process to a system central and/or supervisory controller.

Claims

1. An apparatus for calibrating a variable-air-volume (VAV) device used in an air distribution system to control the flow of conditioned air from a conditioned air source through an air outlet into a zone within a building;

the VAV device being disposed between said conditioned air source and said air outlet and including a sensor for sensing a parameter related to the volume of air flowing through the VAV device and producing a sensor output signal related thereto, and a VAV controller responsive to a control signal from an external zone control device for controlling the VAV device in accordance with the sensor output signal;

said apparatus comprising;

a flow measuring assembly adapted to be coupled to said air outlet and having a flow measuring device for measuring the actual flow of conditioned air from said outlet into said zone and producing a flow output signal related thereto; and

a communication link for communicating said flow output signal to said VAV controller, said VAV controller being responsive to said flow output signal to calibrate said VAV device.

3. The apparatus of claim 1 wherein the flow measuring assembly is coupled via said external zone control device to the VAV controller.

4. The apparatus of claim 1 wherein the flow measuring assembly further includes a display operable for providing a calibration complete indication.

5. The apparatus of claim 1 wherein the VAV controller further includes a memory containing calibration procedures.

6. The apparatus of claim 1 wherein the VAV controller is coupled to a central controller.

7. The apparatus of claim 1 wherein said communication link comprises one of a wired link, a radio frequency link and an infrared link.

2. The apparatus 1 wherein the flow measuring assembly further includes a device controller adapted to receive flow output signal and to communicate the signal via said communication link to the VAV controller in accordance with a communication protocol.

8. A method of calibrating a variable-air-volume (VAV) device used in an air distribution system to control the flow of conditioned air from a conditioned air source through an air outlet into a zone of a building, comprising the steps of:

positioning a flow measuring device to receive the flow of conditioned air from said air outlet;

directing the VAV device to provide one of a plurality of flow conditions;

measuring the resulting actual flow of conditioned air from said air outlet with said flow measuring device and producing a first flow output signal;

communicating said first flow output signal to a controller for said VAV device via a communication link between said flow measuring device and said controller; and

determining a first calibration parameter for the VAV device from said first flow output signal.

9. The method of claim 8 further including the step of signaling to an operator completion of the calibration process.

10. The method of claim 8 further comprising the step of communicating the calibration parameter to a central controller.

11. The method of claim 8 wherein the step of directing the VAV device to provide one of a plurality of flow conditions comprises directing the VAV device to provide one of a zero flow condition, a minimum flow condition and a maximum flow condition.

12. The method of claim 8 further including the steps of:

directing the VAV device to provide a second of said plurality of flow conditions;

measuring the resulting actual flow of conditioned air from said air outlet with said flow measuring device and producing a second flow output signal;

communicating said second flow output signal to the controller for the VAV device; and

determining a second calibration parameter for said VAV device from said second flow output signal.