Adjustable Noise Attenuation Device for Use in Blow Through Air Handler/Furnace with Mixed Flow Blower Wheel

Abstract

An HVAC system comprises an air flow path, a heat exchanger in the air flow path, a blower in the air flow path to move air through the heat exchanger, and at least one Helmholtz resonator in the air flow path. The Helmholtz resonator may be placed in numerous places throughout the air flow path. The Helmholtz resonator may be adjustable. The Helmholtz resonator further may be automatically adjustable. The automatic adjustment may be based on a characteristic of at least one of the blower or the air in the air flow path. Characteristics of air moving through the air flow path may include airspeed, absolute pressure, a pressure change through a portion of the HVAC system, or an audio characteristic. The automatic adjustment may be based on a feedback pressure or an electrical signal from a sensor. The system may have multiple Helmholtz resonators.

What is claimed is: 
     
         1 . An HVAC system comprising:
 an air flow path;   a blower in the air flow path;   a heat exchanger in the air flow path; and   at least one Helmholtz resonator, operably connected to the air flow path.   
     
     
         2 . The HVAC system of  claim 1 , wherein the at least one Helmholtz resonator is positioned in the air flow path of the blower. 
     
     
         3 . The HVAC system of  claim 1 , further comprising a duct downstream or upstream of the heat exchanger, the duct comprising at least one wall, the at least one Helmholtz resonator operably connected to the wall. 
     
     
         4 . The HVAC system of  claim 1 , further comprising an air inlet orifice, wherein the at least one Helmholtz resonator is operably connected to the air inlet orifice. 
     
     
         5 . The HVAC system of  claim 1 , wherein the Helmholtz resonator is adjustable. 
     
     
         6 . An HVAC system comprising:
 an air flow path;   a blower in the air flow path;   a heat exchanger in the air flow path; and   at least one Helmholtz resonator, operably connected to the air flow path,   wherein the at least one adjustable Helmholtz resonator is configured to adjust automatically based on a characteristic of at least one of the blower or an air stream downstream of the blower.   
     
     
         7 . The HVAC system of  claim 6 , wherein the at least one characteristic of the air moving through the HVAC system comprises airspeed, absolute pressure, a pressure change through a portion of the HVAC system, or an audio characteristic. 
     
     
         8 . The HVAC system of  claim 6 , wherein the at least one adjustable Helmholtz resonator is configured to adjust based on a feedback pressure. 
     
     
         9 . The HVAC system of  claim 6 , wherein the at least one adjustable Helmholtz resonator is configured to adjust based on an electrical signal from a sensor. 
     
     
         10 . The HVAC system of  claim 6 , wherein the at least one adjustable Helmholtz resonator is configured to adjust based on a speed of the blower. 
     
     
         11 . The HVAC system of  claim 6 , wherein the air flow path further comprises an inner fan housing, the inner fan housing comprising at least one wall,
 wherein the Helmholtz resonator is positioned in a wall of the inner fan housing.   
     
     
         12 . A method of reducing noise in an HVAC system, the method comprising:
 moving air through an air flow path in the HVAC system using a blower, wherein the HVAC system comprises: the blower and a heat exchanger;   generating a noise signal having acoustic energy in response to the blower moving the air;   moving the air past a Helmholtz resonator operably connected to the blower; and   dampening the acoustic energy of the noise signal with the Helmholtz resonator in response to moving the air past the Helmholtz resonator.   
     
     
         13 . The method of  claim 12 , further comprising adjusting the Helmholtz resonator in response to changes in at least one audio characteristic of the air. 
     
     
         14 . The method of  claim 13 , wherein the step of adjusting is performed automatically. 
     
     
         15 . The method of  claim 13 , wherein the step of adjusting is based on a feedback pressure. 
     
     
         16 . The method of  claim 15 , wherein the feedback pressure is a pressure differential between a pressure downstream of the blower and a pressure upstream of the blower. 
     
     
         17 . The method of  claim 13 , wherein the step of adjusting is based on an electrical signal from a sensor associated with the blower. 
     
     
         18 . The method of  claim 13 , wherein the step of adjusting comprises changing a volume of the Helmholtz resonator. 
     
     
         19 . The method of  claim 12 , wherein the step of adjusting is based on a speed of the blower. 
     
     
         20 . The method of  claim 12 , wherein the Helmholtz resonator is built into a wall that is a portion of a duct ahead of the blower or in an air inlet orifice.