Methods and systems for active sound attenuation in an air handling unit
View Patent ↗A system and method for controlling noise produced by an air handling system is provided. The system includes a source microphone to collect sound measurements from the air handling system and a processor to define a cancellation signal that at least partially cancels out the sound measurements. The system also includes a speaker to generate the cancellation signal. The sound measurements are at least partially canceled out within a region of cancellation. Accordingly, the system further includes a response microphone to collect response sound measurements at the region of cancellation. The processor tunes the cancellation signal based on the response sound measurements.
1. A method for controlling noise produced by an air handling system, comprising:
collecting sound measurements from the air handling system, the sound measurements being defined by acoustic parameters,
determining values for the acoustic parameters based on the sound measurements collected;
calculating offset values for the acoustic parameters, the offset values defining a cancellation signal that at least partially cancels out the sound measurements;
generating the cancellation signal based on the offset values with an array of speakers positioned around a circumference of an inlet cone;
collecting response sound measurements at a region of cancellation; and
tuning the cancellation signal based on the response sound measurements.
2. The method of claim 1 , further comprising collecting sound measurements with a microphone positioned in a hub of a fan wheel.
3. The method of claim 1 , further comprising collecting sound measurements generated within a fan wheel.
4. The method of claim 1 , wherein the acoustic parameters include a frequency and amplitude of the sound measurements, and the calculating operation further comprises calculating an opposite phase and matching amplitude of the acoustic parameters.
5. The method of claim 1 , wherein generating a cancellation signal further comprises generating a cancellation signal in a direction opposite the sound measurements of the air handling system.
6. The method of claim 1 , wherein the cancellation signal destructively interferes with the sound measurements of the air handling system.
7. The method of claim 1 , wherein the noise of the air handling system includes a blade pass frequency of the air handling system.
8. The method of claim 1 , wherein collecting sound measurements further comprises filtering ambient noise from the sound measurements.
9. The method of claim 1 , wherein the generating the cancellation signal further comprises generating a cancellation signal from a plurality of speakers.
10. The method of claim 1 , wherein collecting sound measurements further comprises collecting sound measurements in an inlet cone of the air handling system.
11. A system for controlling noise produced by an air handling system, comprising:
a source microphone to collect sound measurements from the air handling system;
a module to define a cancellation signal that at least partially cancels out the sound measurements;
an array of speakers positioned around a circumference of an inlet cone of a fan unit to generate the cancellation signal;
wherein the sound measurements are at least partially canceled out within a region of cancellation, the system further comprising a response microphone to collect response sound measurements at the region of cancellation; and
wherein the module tunes the cancellation signal based on the response sound measurements.
12. The system of claim 11 , wherein the source microphone is positioned in a hub of a fan wheel.
13. The system of claim 11 , wherein the source microphone is supported on a boom that extends into a hub of a fan wheel.
14. The system of claim 11 further comprising a cover positioned over the source microphone to limit air flow to the source microphone.
15. The system of claim 14 , wherein sound waves pass through the cover.
16. The system of claim 11 , wherein the source microphone collects sound measurements from a fan wheel.
17. The system of claim 11 , wherein the speaker generates the cancellation signal in a direction opposite the sound measurements.
18. The system of claim 11 , wherein the response microphone includes a pair of microphones to filter ambient noise.
19. The system of claim 11 , wherein the source microphone is positioned within an inlet cone of the air handling system.
20. The system of claim 11 , wherein the speaker comprises an aerodynamic surface to reduce an effect of the speaker on the air handling system performance.
21. The system of claim 11 , further comprising a sound attenuating device to passively cancel the sound measurements.
22. A fan unit, comprising:
a source microphone to collect sound measurements from the fan unit;
a module to define a cancellation signal that at least partially cancels out the sound measurements;
an inlet cone and an array of speakers positioned around a circumference of the inlet cone to generate the cancellation signal;
wherein the sound measurements are at least partially canceled out within a region of cancellation, the fan unit further comprising a response microphone to collect response sound measurements at the region of cancellation; and
wherein the module tunes the cancellation signal based on the response sound measurements.
23. The fan unit of claim 22 , further comprising a fan wheel, the source microphone positioned in a hub of the fan wheel.
24. The fan unit of claim 22 , further comprising a fan wheel, the source microphone supported on a boom that extends into a hub of the fan wheel.
25. The fan unit of claim 22 , further comprising a cover positioned over the source microphone to limit air flow to the source microphone.
26. The fan unit of claim 25 , wherein sound waves pass through the cover.
27. The fan unit of claim 22 , further comprising a fan wheel, the source microphone collecting sound measurements from the fan wheel.
28. The fan unit of claim 22 , wherein the speaker generates the cancellation signal in a direction opposite the sound measurements.
29. The fan unit of claim 22 , wherein the response microphone includes a pair of microphones to filter ambient noise.
30. The fan unit of claim 22 , wherein the source microphone is positioned within an inlet cone of the fan unit.
31. The fan unit of claim 22 , wherein the speaker comprises an aerodynamic surface to reduce an effect of the speaker on the fan unit.
32. The fan unit of claim 22 , further comprising a sound attenuating device to passively cancel the sound measurements.
33. A method, comprising:
positioning a source microphone with respect to a fan unit, wherein the source microphone is configured to collect sound measurements from the fan unit;
positioning an array of speakers around a circumference of an inlet cone of the fan unit, wherein the speakers are configured to generate a cancellation signal;
operatively connecting the source microphone and the speakers to a module that is configured to define the cancellation signal that at least partially cancels out the sound measurements;
positioning a response microphone with respect to the fan unit, wherein the response microphone is configured to collect response sound measurements at a region of cancellation; and
tuning the cancellation signal based on the response sound measurements.
34. The method of claim 33 , wherein the positioning a source microphone operation comprises positioning the source microphone in a hub of a fan wheel of the fan unit.
35. The method of claim 33 , wherein the positioning a source microphone operation comprises supporting the source microphone on a boom that extends into a hub of a fan wheel of the fan unit.
36. The method of claim 33 , further comprising positioning a cover over the source microphone to limit air flow to the source microphone.
37. The method of claim 36 , wherein the positioning a cover operation comprises allowing sound waves to pass through the cover.
38. The method of claim 33 , wherein the positioning a source microphone, the positioning a speaker, and the operating connecting operations are repeated for an array of fan units.
39. The method of claim 33 , wherein the positioning a source microphone operation comprises positioning the source microphone within an inlet cone of the fan unit.
40. The method of claim 33 , further comprising positioning a sound attenuating device with respect to the fan unit, wherein the sound attenuating device is configured to passively cancel the sound measurements.
41. A system configured to be used in a fan array, the system comprising:
a source microphone configured to collect sound measurements from a fan unit of the fan array;
a module configured to define a cancellation signal that at least partially cancels out the sound measurements;
an inlet cone and an array of speakers positioned around a circumference of the inlet cone configured to generate the cancellation signal;
wherein the sound measurements are at least partially canceled out within a region of cancellation, the system further comprising a response microphone configured to collect response sound measurements at the region of cancellation; and
wherein the module is configured to tune the cancellation signal based on the response sound measurements.
42. The system of claim 41 , wherein the source microphone is configured to be positioned a hub of a fan wheel.
43. The system of claim 41 , wherein the source microphone is configured to be supported on a boom that extends into a hub of a fan wheel.
44. The system of claim 41 , further comprising a cover positioned over the source microphone to limit air flow to the source microphone.
45. The system of claim 44 , wherein the cover is configured to allow sound waves to pass therethrough.
46. The system of claim 41 , wherein the source microphone is configured to collect the sound measurements from a fan wheel.
47. The system of claim 41 , wherein the speaker is configured to generate the cancellation signal in a direction opposite the sound measurements.
48. The system of claim 41 , wherein the response microphone includes a pair of microphones configured to filter ambient noise.
49. The system of claim 41 , wherein the source microphone is configured to be positioned within an inlet cone of the fan unit.
50. The system of claim 41 , wherein the speaker comprises an aerodynamic surface configured to reduce an effect of the speaker on the fan unit.
51. The system of claim 41 , further comprising a sound attenuating device configured to passively cancel the sound measurements.