Abstract:
A system and method for generating electricity from acoustic energy from an aircraft on a runway. Acoustic wave collectors mounted along the runway collect the acoustic energy and direct such acoustic energy to an associated acoustic converter assembly. A vibrating element is mounted within a housing of the acoustic converter assembly. The vibrating element moves in response to the acoustic energy. This movement draws air into the housing below the vibrating element and then forces the air downward to form an output air flow. The output air flow is directed to an associated turbine assembly to cause a shaft to rotate at a rate proportional to the magnitude of the received output air flow. An associated generator that is coupled to the shaft generates electricity proportionally to the rate of rotation of the shaft. The electricity from each generator is converted and sent to a substation for distribution.

Description:
FIELD 
       [0001]    This disclosure relates to a method and system for producing electricity from acoustical energy at an airport. 
       BACKGROUND 
       [0002]    It is well recognized that airports are generate a great deal of noise during aircraft takeoffs and landings. This acoustic energy is left to dissipate and represents a lost energy resource. Heretofore, there has been no way to recycle the acoustic energy generated by aircraft during takeoffs and landings. 
         [0003]    Accordingly, there is a need for a method and system to harvest the free acoustic energies available at airport runways for electricity generation. 
       SUMMARY 
       [0004]    In one aspect, a system for generating electricity from acoustic energy. The system includes an acoustic wave collector configured to collect acoustic energy and to direct such acoustic energy in a predetermined direction. The system also includes an acoustic converter assembly positioned to receive the acoustic energy from the acoustic wave collector and configured to convert the received acoustic energy into an output air flow. The output air flow has a magnitude proportional to a magnitude of the received acoustic energy. The system further includes a turbine assembly positioned to receive the output air flow from the acoustic converter assembly so that a shaft rotates at a rate proportional to the magnitude of the received output air flow. The system finally includes a generator coupled to the shaft which generates electricity proportionally to the rate of rotation of the shaft. The turbine assembly may be a turbine blade coupled to the shaft. 
         [0005]    In one further embodiment, the acoustic converter assembly comprises a vibrating element mounted within an associated housing. The vibrating element is positioned within the associated housing to move along a first axis. The first axis is parallel to the predetermined direction. The vibrating element is moved back and forth along the first axis proportionally to the received acoustic energy. The movement of the vibrating element draws air into the associated housing below the vibrating element via apertures in a vertical wall of the associated housing and then forces the air downward to form the output air flow. The vibrating element may be a vibrating drum and the vertical wall of the associated housing may form a cylinder. The acoustic converter assembly may further include an acoustic waveguide mounted above the vibrating element. The acoustic waveguide has a wider inlet adjacent to the acoustic wave collector and a narrower outlet adjacent to the vibrating element. The acoustic waveguide may have a conical form. 
         [0006]    In another further embodiment, the acoustic converter assembly includes a plurality of converters. Each converter includes a vibrating element mounted within an associated housing. The vibrating element is positioned within the associated housing to move along a first axis. The first axis is parallel to the predetermined direction. The vibrating element is moved back and forth along the first axis proportionally to the received acoustic energy. The movement of the vibrating element draws air into the associated housing below the vibrating element via apertures in a wall of the associated housing and forces the air downward to form a portion of the output air flow. Each of the vibrating elements may be a vibrating drum. Each of the vertical walls of the associated housings may form a cylinder. Each converter may further include an acoustic waveguide mounted above the associated vibrating element. The acoustic waveguide has a wider inlet adjacent to the acoustic wave collector and a narrower outlet adjacent to the associated vibrating element. Each acoustic waveguide may have a conical form. 
         [0007]    In another aspect, a system for generating electricity from acoustic energy. The system includes a plurality of acoustic wave collectors configured to collect acoustic energy and to direct such acoustic energy in a predetermined direction. The system also includes an acoustic converter assembly positioned to receive the acoustic energy from the plurality of acoustic wave collectors and configured to convert the received acoustic energy into an output air flow. The output air flow has a magnitude proportional to a magnitude of the received acoustic energy. The system further includes a turbine assembly positioned to receive the output air flow from the acoustic converter assembly so that a shaft rotates at a rate proportional to the magnitude of the received output air flow. The system finally includes a generator coupled to the shaft which generates electricity proportionally to the rate of rotation of the shaft. The turbine assembly may be a turbine blade coupled to the shaft. 
         [0008]    In a further embodiment, the acoustic converter assembly includes a plurality of converters. Each converter is positioned adjacent to an associated one of the plurality of acoustic wave collectors. Each converter has a vibrating element mounted within an associated housing. The vibrating element is positioned within the associated housing to move along a first axis. The first axis is parallel to the predetermined direction. The vibrating element is moved upward and downward proportionally to the received acoustic energy. The movement of the vibrating element draws air into the associated housing below the vibrating element via apertures in a wall of the associated housing and forces the air downward to form a portion of the output air flow. Each of the vibrating elements may be a vibrating drum. Each of the vertical walls of the associated housings may form a cylinder. Each converter may further include an acoustic waveguide mounted above the associated vibrating element. The acoustic waveguide has a wider inlet adjacent to the acoustic wave collector and a narrower outlet adjacent to the associated vibrating element. Each acoustic waveguide may have a conical form. 
         [0009]    In yet another aspect, a method for generating electricity from acoustic energy. First, acoustic energy is collected in an acoustic wave collector and such acoustic energy is directed in a predetermined direction. The acoustic energy is received from the acoustic wave collector and converted into an output air flow, the output air flow having a magnitude proportional to a magnitude of the received acoustic energy. The output air flow is received from the acoustic converter and, via a turbine assembly, causes a shaft to rotate at a rate proportional to the magnitude of the received output air flow. Finally, a generator generates electricity proportionally to the rate of rotation of the shaft. The received acoustic energy may be converted to an output air flow by a vibrating element mounted within an associated housing. The vibrating element is positioned within the associated housing to move along a first axis. The first axis is parallel to the predetermined direction. The vibrating element is moved back and forth along the first axis proportionally to the received acoustic energy. The movement of the vibrating element draws air into the associated housing below the vibrating element via apertures in a vertical wall of the associated housing and then forces the air downward to form the output air flow. The vibrating element may be a vibrating drum. The vertical wall of the associated housing may form a cylinder. The acoustic converter assembly may further include an acoustic waveguide mounted above the vibrating element. The acoustic waveguide has a wider inlet adjacent to the acoustic wave collector and a narrower outlet adjacent to the vibrating element. 
         [0010]    The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The following detailed description, given by way of example and not intended to limit the present disclosure solely thereto, will best be understood in conjunction with the accompanying drawings in which: 
           [0012]      FIG. 1  is an illustration of an acoustical-to-electricity energy conversion system in accordance with an advantageous embodiment; 
           [0013]      FIGS. 2A and 2B  are partial and full illustrations of an upper portion of the acoustical-to-electricity energy converter assembly in accordance with an advantageous embodiment; 
           [0014]      FIG. 3  is an illustration of a lower portion of the acoustical-to-electricity energy converter assembly in accordance with an advantageous embodiment; 
           [0015]      FIG. 4  is a block diagram showing the electrical connection of the acoustical-to-electricity energy conversion system in accordance with an advantageous embodiment; and 
           [0016]      FIG. 5  is an illustration of an acoustical waveguide for use with the acoustical-to-electricity energy converter assembly in accordance with a further advantageous embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    In the present disclosure, like reference numbers refer to like elements throughout the drawings, which illustrate various exemplary embodiments of the present disclosure. 
         [0018]    Referring now to the drawings, and in particular to  FIG. 1 , a system for converting acoustical energy into electricity is shown. In particular, an aircraft  100  moving along a runway  130 , either during landing or takeoff, generates a great deal of acoustic energy, mostly from the engines mounted on aircraft  100 . The acoustic energy is shown schematically in  FIG. 1  as lines  105 . The system includes series of converter assemblies  115  coupled to generators  110 . The converters assemblies  115  are mounted along the sides of runway  130  with an associated generator  110  located adjacent to each converter assembly  115 . As aircraft  100  moves along runway  130 , each converter assembly  115  captures the acoustic wave energy  105  generated by the aircraft  100  as the aircraft  100  passes and converts it to an air current, as discussed below in more detail with respect to  FIGS. 2A and 2B . The generated air current drives a turbine blade coupled to an electrical generator, as shown in  FIG. 3 , to generate electricity. The output of the electrical generator is routed through a converter and then merged into underground power transmission lines  120  for distribution to the users, as shown in  FIG. 4 . 
         [0019]    Referring now to  FIGS. 2A and 2B , each converter assembly  200  ( FIG. 2B ) includes at least one acoustic wave collector  235  ( FIG. 2A ) shaped and sized for optimum collection of the incoming acoustic waves  105  from a passing aircraft and coupled to a converter  205 . The shape and size of the acoustic wave collector  235  may be the same for each converter assembly  200  or may be different depending on the location of converter assembly  200  along the runway  130  ( FIG. 1 ). Acoustic wave collector  235  has a curved internal surface and is positioned to collect the maximum possible acoustic radiations from the aircraft engines. As such, each of the converter assemblies  115  shown in  FIG. 1  has a slightly different orientation with respect to the runway  130 . As one of ordinary skill in the art will readily recognize, in other embodiments each converter assembly  115  may have the same orientation with respect to runway  130 .  FIG. 2A  shows the detail of a single converter  205  and single acoustic wave collector  235 , while  FIG. 2B  shows how four such converters  205  can be mounted within a larger assembly  200  (with the collector or collectors  235  not shown). Converter assembly  115  shown in  FIG. 1  corresponds to the entire assembly (i.e., either a single converter  205  and associated acoustic wave collector  235  or an assembly  200  of multiple converters  205  and, as discussed below, one or more associate acoustic wave collectors  235 ). 
         [0020]    Referring now to  FIG. 2A , acoustic wave collector  235  preferably has a curved internal surface that collects and guides the acoustic waves  105  from aircraft  100  to a converter  205  that includes a vibrating drum  215  mounted in a converter drum housing  255 . Vibrating drum  215  moves up and down, as shown by displacement line  250 , when acoustic waves are received via acoustic wave collector  235 . As one of ordinary skill in the art will readily recognize, converter drum housing  255  may be positioned in any orientation, e.g., horizontally instead of vertically, in which case the vibrating drum  215  will move back and forth along a central axis of drum housing  255 . Furthermore, although vibrating drum  215  and drum housing  255  are shown having a cylindrical cross-section in  FIG. 2B , one of ordinary skill in the art will readily recognize that other types of cross-sections may be employed, e.g., square, rectangular or oval. In  FIG. 2B , four adjacent converters  205  are shown, each consisting of a vibrating drum  215  mounted in a converter drum housing  255  (as detailed in  FIG. 2A ) to form converter assembly  200  (for clarity, the one or multiple acoustic wave collectors  235  are not shown in  FIG. 2B ). As one of ordinary skill in the art will readily recognize, the number of converters included is arbitrary and can range from a single converter to four or more, depending, at least in part, on the amount of acoustic energy collected at collector  235 . Further, converter assembly  200  may include a single acoustic wave collector  235  for all four converters  205  or a separate acoustic wave collector  235  for each of the converters  205 . The collected acoustic waves  105  pass through a converging path created by the acoustic wave collector  235  and enter a chamber within converter drum housing  255  above vibrating drum  215  as the directed acoustic waves  210 . 
         [0021]    Vibrating drum  215  vibrates within a fixed range of motion at the same frequency as the incoming directed acoustic waves  210 , with the magnitude of vibration proportional to the intensity of the incoming directed acoustic waves  210 . When excited by the incoming directed acoustic waves  210 , vibrating drum  215  moves up and down (in the orientation shown in  FIG. 2A ) within the cylindrical chamber of converter drum housing  255  (along displacement line  250 ). As it vibrates, vibrating drum  215  acts as an air pump to draw in ambient air through the air intake holes  220  in the wall of housing  255  and then push the drawn-in ambient air down though air flow guide channel  225 . The vibrating drum  215 , when excited by received acoustic waves, cause an air flow  230  that is pushed down along guide channel  225  and through exit hole  240 . 
         [0022]    As discussed above, converter assembly  200  preferably includes a cluster of multiple acoustic converters  205  (four are shown in  FIG. 2B ) to maximize the collection of acoustic energy. Each converter  205  generates an air flow through an associated exit hole  240  that is directed to a turbine chamber  355  ( FIG. 3 ) positioned below converter assembly  200 . As one of ordinary skill in the art will readily recognize, the positional relationship between converter assembly  200  and turbine chamber  355  is arbitrary and is preferably selected to minimize any air flow losses between converter assembly  200  and turbine chamber  355 . 
         [0023]    Referring now to  FIG. 3 , turbine chamber  355  is preferably positioned below converter assembly  200  and includes air inlet holes  305  that mate to the air exit holes  240  of converter assembly  200 . Air generated from the converters  205  in converter assembly  200  enters turbine chamber  355  as airflow  310  and drives turbine blades  320 , causing the shaft  325  coupled to turbine blades  320  to rotate proportionally to the magnitude of the received airflow. Turbine shaft  325  is coupled to a generator  110  via a pair of bevel gears  335 . As one of ordinary skill in the art will readily recognize, other types of couplings can be used to couple turbine shaft  325  to the generator  110  (e.g., a universal joint), depending on, at least in part, the selected orientation of generator  110  with respect to turbine shaft  325 . As the turbine blades  320  (and shaft  325 ) rotates, generator  110  produces electricity on an output  345 . The airflow  310 , after driving the turbine blades  320 , exits from the holes  330  located at the bottom of turbine chamber  355 . 
         [0024]    Referring now to  FIG. 4 , a block diagram is shown of a system  400  demonstrating how the generators  110  shown in  FIGS. 1 and 3  are coupled to provide utility grade power. In particular, each generator  401 ,  402 ,  403  . . .  404  is coupled to an associated converter  411 ,  412 ,  413  . . .  414 . Each converter  411 ,  412 ,  413  . . .  414  may, for example, convert the variable frequency input AC voltage from generator  401 ,  402 ,  403  . . .  404  to a fixed frequency output AC voltage via a rectifier, energy storage device and voltage inverter, as is known in the art. The output from each converter  411 ,  412 ,  413  . . .  414  is provided to a substation  420 , which may, for example, combine the power from each converter  411 ,  412 ,  413  . . .  414  via a three phase line filter and associated transformer to produce utility grade power on an output  430 . Output  430  may be coupled, on one embodiment, to local utility lines at the airport for internal use or via an appropriate interface to commercial utility lines for credit from the local power company. As one of ordinary skill in the art will readily recognize, there are numerous alternative methods available to convert the electrical output from each generator  401 ,  402 ,  403  . . .  404  into utility grade power. As one of ordinary skill in the art will readily recognize, the system disclosed herein may be used for other purposes. For example, the electricity generated by each generator  401 ,  402 ,  403  . . .  404  may be coupled to charge batteries that are part of airport back-up systems. 
         [0025]    Referring now to  FIG. 5 , in a further embodiment converter assembly  200  may include an acoustic waveguide  500  mounted within converter drum housing  255  above vibrating drum  215 . Acoustic waveguide  500  is fixed within converter drum housing  255  by couplings  510  and is preferably conical in form, with a wider inlet at an upper end  520  and a narrower outlet at a lower end  550 . Acoustic waveguide  500  amplifies the directed acoustic waves  210  received at the upper end  520 . Acoustic waveguide  500  may also include a spring  530  having an upper end mounted at the lower end  550 . A lower end of spring  530  is connected directly to vibrating drum  215 , preferably within a recess  540  in a top portion of vibrating drum  215 . Spring  530  further amplifies the received converted acoustic waves  210 , to further increase the movement of vibrating drum  215  and thus increase the amount of air directed downward to turn the turbine blades  320 . Acoustic waveguide  500  is shown with a conical form in  FIG. 5 . As one of ordinary skill in the art will readily recognize, other forms may be employed. The alternative form may depend, for example, on the cross-sectional form of converter drum housing  255 . In one alternative embodiment, for example, acoustic wave guide  500  may have an inverted pyramid form when converter drum housing  255  has a square cross section. 
         [0026]    Although the present disclosure has been particularly shown and described with reference to the preferred embodiments and various aspects thereof, it will be appreciated by those of ordinary skill in the art that various changes and modifications may be made without departing from the spirit and scope of the disclosure. It is intended that the appended claims be interpreted as including the embodiments described herein, the alternatives mentioned above, and all equivalents thereto.