Patent Publication Number: US-2013251526-A1

Title: System and Method for Generating Electricity from Aerodynamic Drag

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a system and method for producing electricity from the movement of a vehicle. More specifically, the present invention makes use of the aerodynamic drag created by the movement of a vehicle through a fluid medium and converts that drag into electrical energy. 
     2. Description of the Related Art. 
     Aerodynamic drag is the fluid drag force that acts on any moving solid body in the direction of the fluid freestream flow. From the solid body&#39;s perspective, the drag comes from forces due to pressure distributions over the body surface and forces due to skin friction, which is a result of viscosity of the fluid. 
     Aerodynamic drag is present in any system in which a solid body is in movement relative to the fluid, such as in the case of the movement of vehicles (e.g., a car or airplane) being propelled along a roadway or through air. The force may be used to create mechanical work that can subsequently be converted to electrical energy. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system for harnessing energy created by a region of aerodynamic drag of a moving vehicle. The system comprising at least one traveling surface (such as a road or runway) having an intended direction of travel, and at least one turbine assembly having a shaft, a plurality of air-engaging members fixed to the shaft, and an axis of rotation concentrically aligned with the shaft. The turbine assembly is positioned proximal to the at least one traveling surface to intersect the region of aerodynamic drag created by the moving vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-2  show an embodiment of the system in use at an airport. 
         FIGS. 3-4  show a second embodiment of the system in use along a section of roadway. 
     
    
    
     DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an embodiment of the present invention in use at an airport. A runway  20  built on a ground surface  22 , which runway extends in a first direction to provide a path for arriving and departing airplanes. A turbine assembly  24  is positioned proximal to one end of the runway  20 . The turbine assembly  24  includes a shaft  26  with a horizontal axis of rotation  28  and a plurality of air-engaging members  30  (e.g., blades). The shaft  26  is connected to an electrical generator  32 . Although only one turbine assembly  24  is shown, alternative embodiments of the system anticipate the use of a plurality of turbine assemblies located proximal to the end of the runway  20 . 
     Although the turbine assembly  24  shown in  FIG. 1  comprise blades  30 , such as those found in Darrieus-style turbines, alternative embodiments contemplate turbines having a plurality of scoops, such as those in used with Savonius-type turbines. Moreover, although the turbine assembly  24  shown in  FIG. 1  is horizontal-axis turbines, alternative embodiments contemplate the use of vertical axis turbines. 
     Still referring to  FIG. 1 , an airplane  34  is shown moving in the first direction and descending in elevation relative to the runway  20  in anticipation of landing. As the airplane  34  moves through the air, regions  36  of aerodynamic drag are created behind the airplane  34 . As the airplane  34  passes over, but proximal to, the turbine assembly  24  while landing, the aerodynamic drag regions  36  intersects with the blades  30  and exert a rotational force on the shaft  26 , causing the shaft  26  to rotate in a first rotational direction RD  1 . This rotation causes the generator  32  to create electricity, which may be transferred to an on-site electrical storage bank or provided to a power grid. 
     As shown in  FIG. 2 , after the airplane  34  touches down on, and travels along, the runway  20 , the aerodymanic drag regions  36 , while decreasing in volume with the decreasing speed of the airplane  34 , exert force on a plurality of turbine assemblies  24  positioned on either side of the runway  20 , causing rotation of the shafts  26  of the turbine assemblies  24  in the first rotational direction RD 1  and the subsequent generation of electricity by the associated generators  32 . In an alternative embodiment, a turbine assembly may also be positioned at the second end (not shown) of the runway  20  to harness the energy of the aerodynamic drag of a departing airplane. 
       FIG. 3  shows an alternative embodiment of the present invention, which comprises a plurality of vertical-axis turbine assemblies  38 , each with a vertical axis of rotation  40 , positioned between two opposing travel surfaces  42  (e.g., a road median  44 ), which are shown as highways built on a ground surface  46 . Each of the turbine assemblies  38  are identical to the turbine assemblies  24  shown in  FIGS. 1-2  except they are vertically oriented. In this embodiment, the turbine assemblies  38  comprise a plurality of inferior, or lower, turbine assemblies  48  and an aligned plurality of superior, or upper, turbine assemblies  50 . 
       FIG. 3  further shows the roadways  42  in use by a typical personal vehicle, such as a sport utility vehicle (SUV)  52 . The SUV  52  travels along the roadway  42  in a first direction, creating a region  54  of aerodynamic drag behind it. The region  54  of drag exerts its force on each of the lower turbine assemblies  48  as the SUV  52  moves along the roadway  42 , causing the shafts of the lower turbine assemblies  48  to rotate and cause generation of electricity. The generated electricity may then be stored in local power storage cells or transmitted remotely to a transmission grid. Because of the profile of the SUV  52 , the drag region  54  does not intersect the upper turbine assemblies  50 , resulting in more efficient generation of electricity. 
       FIG. 4  depicts a tractor-trailer  56  traversing the roadway  42  in the first direction, which creates a second region  58  of aerodynamic drag larger than the first region  54  shown in  FIG. 3  because of the larger aerodynamic profile of the tractor-trailer  56  relative to the SUV  52 . The second region  58  of drag operates on the both the lower and upper turbine assemblies  48 ,  50 . 
     The present invention is described in terms of preferred embodiments in which a specific system and method are described. Those skilled in the art will recognize that alternative embodiments of such system, and alternative applications of the method, can be used in carrying out the present invention. Other aspects and advantages of the present invention may be obtained from a study of this disclosure and the drawings, along with the appended claims. Moreover, the recited order of the steps of the method described herein is not meant to limit the order in which those steps may be performed.