EP2941971A1 - Footwear energy harvesting apparatus and method - Google Patents
Footwear energy harvesting apparatus and method Download PDFInfo
- Publication number
- EP2941971A1 EP2941971A1 EP15166787.0A EP15166787A EP2941971A1 EP 2941971 A1 EP2941971 A1 EP 2941971A1 EP 15166787 A EP15166787 A EP 15166787A EP 2941971 A1 EP2941971 A1 EP 2941971A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- footwear
- turbine
- reservoir
- energy harvesting
- pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
- A43B13/18—Resilient soles
- A43B13/20—Pneumatic soles filled with a compressible fluid, e.g. air, gas
- A43B13/203—Pneumatic soles filled with a compressible fluid, e.g. air, gas provided with a pump or valve
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B3/00—Footwear characterised by the shape or the use
- A43B3/34—Footwear characterised by the shape or the use with electrical or electronic arrangements
- A43B3/38—Footwear characterised by the shape or the use with electrical or electronic arrangements with power sources
Definitions
- the present invention relates to an apparatus set in footwear for the purpose of generating electricity for the purposes of powering electrical accessories carried by the wearer, and the method therefore.
- the problem relates to the generation of electricity by a person while walking, to provide electrical energy to drive personal electronic equipment carried by the person.
- an energy harvesting system for footwear comprising a first gaseous pump formed at the sole of the footwear and a second gaseous pump formed at the heel of the footwear.
- a reservoir is mounted to the upper of footwear in fluid communication with and downstream of the first and second pumps and adapted to receive pressurized gas exiting from the pumps.
- a turbine having an output shaft is mounted on the footwear upper, in fluid communication with and downstream of the reservoir.
- the turbine includes an inlet port section for receiving the pressurized gas from the reservoir, when a predetermined pressure threshold is attained in the reservoir, so as to activate the turbine; and an electrical generator mounted on the upper, downstream of the turbine and disengageably connected with the turbine output shaft so that the generator is engaged by the shaft when a predetermined shaft velocity threshold has been attained whereby electricity may be generated in order to energize or be stored by a device worn by the bearer of the footwear.
- the turbine inlet port section includes a diffuser and the rotor includes an input shaft coaxial with the output shaft.
- the turbine includes eight stages.
- a multistage, axial turbine for converting energy from a pressurized gas to mechanical energy which may be used within a footwear energy harvesting system.
- the turbine includes a casing having an inlet and an outlet at axially aligned opposite ends of the casing, and the casing houses a cylindrical hollow stator and an elongated rotor concentric with the stator.
- the rotor includes a plurality of stages of radially extending rotor blades spaced circumferentially in each stage, while the stator is provided with rows of radially extending stator vanes circumferentially spaced apart in each row and the rows are located inter-stage of the rotor blade stages.
- the casing includes a diffuser at the inlet provided to receive the pressurized gas and to direct it to the rotor and stator.
- the casing is provided with bearings at the inlet and the outlet and the rotor has an upstream shaft and an output shaft coaxial with the upstream shaft and the shafts rotating freely while being supported in the respective bearings.
- the turbine For use in footwear in order to harvest energy from walking the turbine must miniaturized in order to fit in a footwear.
- the axial turbine is miniaturized for use within a footwear energy harvesting system.
- the turbine may have around eight stages.
- the turbine might also have eight stages and the rotor blades increase in height from 0.692 mm at the upstream stage to 1.004 mm at the downstream 8 th stage.
- a method of harvesting energy from footwear comprising the steps of compressing a gas in a chamber at the sole of the footwear transferring the compressed gas to a second chamber at the heel of the footwear; further compressing the gas in the second chamber; transferring the compressed gas from the second chamber to a reservoir; repeating the compression steps until the pressure in the reservoir has reached a threshold level; once the pressure level in the reservoir has reached the threshold level, passing the pressurized gas through a turbine to convert the energy from the pressurized gas to mechanical energy by rotating the turbine rotor and dependent shaft to reach a speed threshold; once the speed threshold of the shaft has been reached, engaging the shaft with an electric generator; storing the electricity and/or driving a device carried by the bearer of the footwear.
- FIG. 1 there is shown a work boot 10 having a heel 12 and a sole 14 along with an upper 16.
- the heel 12 has a heel plate 13 that is hinged, at its forward portion, at 18 to the boot.
- the heel plate 12 can pivot in a vertical plane about an axis normal to the vertical plane at the hinge 18.
- a flexible, impermeable bellows wall 20 defines a bellows chamber 21 between the boot and the pivoting heel 12.
- a oneway air inlet valve 20a is defined in the flexible wall 20.
- outsole 14a pivots about a hinge 22 in the toe region of the boot 10.
- the outsole 14 can pivot in a vertical plane about an axis at the hinge 22 that is normal to the vertical plane.
- a flexible, impermeable bellows wall 24 is provided defining a bellows chamber 25 between the boot and the pivoting outsole 14a.
- a oneway air inlet valve 25a is provided in the bellows wall 24, which otherwise is airtight.
- An air conduit 32 communicates the bellows chamber 25 with the bellows chamber 21.
- a one-way check valve 31 interrupts the conduit 32 to prevent the air from returning into the chamber 25.
- the precompressed air is now compressed to between 25-30 psi (172 kPa - 207 kPa); partly because of the smaller heel area providing a smaller chamber 21.
- the compressed air from the bellows chamber 21 passes through the conduit 28 to the reservoir 26, interrupted by a one-way check valve 30.
- the reservoir 26, mounted on the side of the upper 16 of the boot 10, typically has a capacity of 12 in 3 (197 cm 3 ), in order to provide storage capacity for the compressed air before it is released to the turbine 34.
- An air conduit 36 communicates the reservoir 26 to the turbine 34.
- the air conduit 36 is interrupted by a pressure control valve 38. It was determined that the ideal pressure for delivering the air to the turbine 34 is between 30 and 40 psi, but the latter is preferred.
- a control panel 40 is mounted to the side of the upper 16 and preferably between inner-layers forming the upper 16.
- An air-line 42 extends between the valve 38 and a pressure regulator 43 on the control panel 40.
- the valve 38 is opened by the pressure regulator, when the pressure threshold e.g. 40 psi is attained.
- the turbine 34 may be approximately 51 mm long and less than 10 mm in diameter.
- the turbine is considered to be minituarised and other similar dimensions are considered to be equivalent.
- the criteria is that it must be able to be mounted to the upper 16 of boot 10.
- the turbine 34 is made up of a tubular casing 60 enclosing a cylindrical stator 70, in the form of a sleeve, with a concentric, elongated rotor 68.
- the rotor 68 includes a coaxial shaft 66 extending upstream and downstream thereof.
- An inlet cap 62 is threaded onto the external threads 61 of the tubular casing 60.
- an outlet cap 64 At the other end of the casing 60 is an outlet cap 64 with it external threads 82 adapted to engage the internal threads 63 of the tubular casing 60.
- the downstream or output portion of shaft 66 is supported by the inner race 80 of a bearing 81 mounted within the outlet cap 64.
- an inlet diffuser 72 At the other end of the casing 60, an inlet diffuser 72, in the form of a cylindrical housing, has an inner race 78, part of an integrated bearing 79, supporting the upstream end of shaft 66.
- the rotor 68 mounts several stages of rotor blades 84. Preferably eight stages are provided.
- the blades 84 extend radially outwardly from the core surface of the rotor 68 and are spaced apart circumferentially, equally in each stage.
- the stator 70 is fabricated in semi-cylindrical segments 70a and 70b, forming a sleeve which is mounted within the casing 60 and is concentric with the rotor 68. In certain conditions the stator may be in three segments. As shown in Figs. 6a and 6b , the stator 70 has a plurality of rows of vanes 86, each extending radially inwardly. The vanes 86 are spaced apart equally in each row and the rows are inter stage with the rotor stages. Back to Figs.
- the diffuser 72 includes an annular array of bores 74 arranged to pass the compressed air into the turbine 34.
- the rotor 68 and stator 70 will be described in more detail herein below.
- air entering the turbine 34 will cause the shaft 66 to rotate at an increasingly higher speed, when the shaft 66 is disengaged and rotating freely.
- the rotational speed of the shaft 66 is measured by an optical angular velocity sensor 50 located in the control panel 40.
- an optical fiber 52 is directed to a marker on the shaft 66.
- the marker may be a small bore through shaft 66.
- the shaft 66 is allowed to rotate freely until it reaches a threshold sufficient to allow it to be coupled to the generator shaft 46.
- the velocity will preferably attain 90,000 rpm when the air pressure is 40 psi.
- Generator 44 which is meant to convert the mechanical energy into electricity may also be used to start the rotation of the rotor. The generator would then be driven by battery 90.
- a multi-stage axial turbine 34 used to extract the available energy stored in the pressurized storage tank 26, is designed to transform the energy stored in terms of pressure and temperature into electrical energy.
- the tangential velocity of the airflow is a high value but is limited by the speed of sound at standard ambient temperature. It is also limited by the need to keep frictional losses as low as possible.
- the mass flow rate is assumed to be constant as the available mass of air stored in the tank 26 discharges very quickly through the turbine 34.
- the duration of the constant velocity period is very short and what is observed is rather a regime of acceleration followed by a deceleration time.
- Figure 5a and 5b show a schematic view of the preferred turbine geometry.
- the turbine geometry is characterized by the following elements: the number of stages, the blade section at each stage, the mid-radius, the angle of attack and the trailing-edge angle of the rotor blades and the stator vanes.
- the radius of the rotor hub is R1 while the rotor tip is R3.
- the radius of the inner rim of the stator is R4 while the stator vane tip is R2. It has been shown that clearances, defined by the distance between the stator vane tips and the rotor hub R2-R1 and the distance between the rotor blade tips and the stator rim R4-R3, should be kept as small as possible. Thus, the air leakage from one stage to another is minimized.
- the optimum design was manufactured with clearance R2-R1 of 0.120 mm and clearance R4-R3 of 0.100 mm.
- FIG. 5b The preferred rotor blade design and stator blade design is shown in figures 5b , 6a , 6b and 6c .
- the blade height of the rotor varies from 0.692 mm at stage 1 to 1.004 mm at stage 8.
- the number of stages should be as low as possible to limit the manufacturing difficulties, but high enough to limit tangential velocity of the air flow.
- the 8-stage turbine assembly 34 is shown in Fig. 6a, 6b and 6c .
- the rotor blades 84 are shown extending radially from the rotor 68 while the stator vanes 86 are shown extending radially inwardly from the inner periphery of the stator 70.
- the inlet temperature T i i and exit temperature T e i at stage i exhibits a temperature drop, such that there is, according to the above equation, a pressure drop and an air density drop across the stages of the turbine. This results in an increase of the turbine exit airflow.
- the turbine 34 has been manufactured by rapid prototyping using Multi Jet Modeling technique (MJM 3D printer from 3D Systems). CNC can also be used.
- MITM 3D printer from 3D Systems. CNC can also be used.
- Fig. 2 and 7 there is shown a diagram of the circuit.
- the air valve 38 is open and closed by an electronic switch 38a controlled by a CPU 88 in response to the pressure sensor 43.
- the pressurized air from the storage tank 26 is passed to the turbine 34 only when the pressure threshold has been met, as determined by the CPU 88.
- the threshold is determined to be 40 psi.
- the pressurized air enters the turbine 34 to rotate the rotor 68 to a high velocity, in the range of 100,000 rpm.
- the shaft velocity is measured by the optical angular velocity sensor 50 and the information is sent to the CPU 88.
- the shaft 66 of the turbine 34 is coupled to the generator 44 only when a shaft speed threshold has been attained e.g. 90,000 rpm.
- the CPU 88 sends a signal to ON switch 54 in order to engage the shaft 66 to the generator shaft 46.
- the generator 44 will generate electrical energy which can be stored in battery 90.
- the rotor 68 may be initially rotated by electrical current supplied from the battery 90. The inertia of the rotating rotor 68 facilitates the acceleration of the rotor to its threshold velocity by the compressed air.
- the generator shaft 46 causes a pulsing of the electrical current produced by the generator 44.
- a regulator 92 may be provided for averaging the current flow to the battery 90 by way of a charger.
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
Abstract
Description
- The present invention relates to an apparatus set in footwear for the purpose of generating electricity for the purposes of powering electrical accessories carried by the wearer, and the method therefore.
- The problem relates to the generation of electricity by a person while walking, to provide electrical energy to drive personal electronic equipment carried by the person.
- There has been a history of endeavors to harvest energy from footwear in order to produce electrical power for the purpose of energizing various accessories worn by a person, such as to operate "...an electric lamp, a heating coil, a small wireless outfit, a therapeutic appliance..." as described in
US patent 1,506,282 Barbieri in 1924 . Since then many attempts have been made as illustrated byLakic in US4,674,199 January 1987 ;US4,736,530 April 1988 ;US4,782,602, November 1988 ;US4,845,338 July 1989 andUS4,941,271, July 1990 ;Chen in US5,167,082 December 1992 ;US5,367,788 November 1994 and5,495,682 March 1996 . More recently there has beenLandry US6,201,314 March 2001 ;Le et al US6,255,799 July 2001 ;Sarich US6,281,594 August 2001 andYang US7,956,476 June 2011 . A paper entitled Parasitic Power Harvesting in Shoes by John Kymissis et al, from the MIT Media Laboratory, was presented at the Second IEEE International Conference on Wearable Computing in August, 1998. - With increased use of power-consuming portable electronics, the need for compact and lightweight power sources to replace batteries is becoming more urgent. Harvesting energy from walking such as from the force developed in compressing footwear soles and heels has been shown to generate anywhere from 1 to 7 W cap (continuous average power). However the challenge remains in converting this mechanical energy into useful electricity with miniaturize components.
- It is therefore an aim of the present invention to provide as a solution, an improved footwear energy harvesting apparatus and related method.
- Therefore, in accordance with the present invention, there is provided an energy harvesting system for footwear comprising a first gaseous pump formed at the sole of the footwear and a second gaseous pump formed at the heel of the footwear. A reservoir is mounted to the upper of footwear in fluid communication with and downstream of the first and second pumps and adapted to receive pressurized gas exiting from the pumps. A turbine having an output shaft, is mounted on the footwear upper, in fluid communication with and downstream of the reservoir. The turbine includes an inlet port section for receiving the pressurized gas from the reservoir, when a predetermined pressure threshold is attained in the reservoir, so as to activate the turbine; and an electrical generator mounted on the upper, downstream of the turbine and disengageably connected with the turbine output shaft so that the generator is engaged by the shaft when a predetermined shaft velocity threshold has been attained whereby electricity may be generated in order to energize or be stored by a device worn by the bearer of the footwear.
- More specifically the turbine inlet port section includes a diffuser and the rotor includes an input shaft coaxial with the output shaft.
- Preferably the turbine includes eight stages.
- In another aspect, there is provided a multistage, axial turbine for converting energy from a pressurized gas to mechanical energy which may be used within a footwear energy harvesting system. The turbine includes a casing having an inlet and an outlet at axially aligned opposite ends of the casing, and the casing houses a cylindrical hollow stator and an elongated rotor concentric with the stator. The rotor includes a plurality of stages of radially extending rotor blades spaced circumferentially in each stage, while the stator is provided with rows of radially extending stator vanes circumferentially spaced apart in each row and the rows are located inter-stage of the rotor blade stages. The casing includes a diffuser at the inlet provided to receive the pressurized gas and to direct it to the rotor and stator. The casing is provided with bearings at the inlet and the outlet and the rotor has an upstream shaft and an output shaft coaxial with the upstream shaft and the shafts rotating freely while being supported in the respective bearings. For use in footwear in order to harvest energy from walking the turbine must miniaturized in order to fit in a footwear.
- More specifically the axial turbine is miniaturized for use within a footwear energy harvesting system.
-
-
- The trailing edge of the stator vane may have a value α1 = 86° and the trailing edge of the rotor blade may have a value β2 = 35°. The turbine might also have eight stages and the rotor blades increase in height from 0.692 mm at the upstream stage to 1.004 mm at the downstream 8th stage.
- In yet another aspect there is a method of harvesting energy from footwear comprising the steps of compressing a gas in a chamber at the sole of the footwear transferring the compressed gas to a second chamber at the heel of the footwear; further compressing the gas in the second chamber; transferring the compressed gas from the second chamber to a reservoir; repeating the compression steps until the pressure in the reservoir has reached a threshold level; once the pressure level in the reservoir has reached the threshold level, passing the pressurized gas through a turbine to convert the energy from the pressurized gas to mechanical energy by rotating the turbine rotor and dependent shaft to reach a speed threshold; once the speed threshold of the shaft has been reached, engaging the shaft with an electric generator; storing the electricity and/or driving a device carried by the bearer of the footwear.
- Reference will now be made to the accompanying drawings, showing by way of illustration a particular embodiment of the present invention and in which:
-
Figure 1 is a schematic side elevation of a boot showing the location of the miniaturized components of one embodiment; -
Figure 2 is a block diagram illustrating the components shown inFig. 1 ; -
Figure 3a is an exploded view of a turbine in accordance with the embodiment; -
Figure 3b is a perspective view, showing various details of the turbine shown inFig. 3a ; -
Figure 4 is a schematic view of the storage tank and turbine of the embodiment; -
Figure 5a is a schematic view of the turbine in accordance with the embodiment; -
Figure 5b is a schematic view of a crossection of the stator vanes and rotor blades of the embodiment of the turbine; -
Figure 6a is a longitudinal cross section of the turbine in accordance with the embodiment; -
Figure 6b is a longitudinal crosssection of the stator shown inFig. 6a ; -
Figure 6c is a fragmentary perspective view of the rotor shown inFig. 6a ; and -
Figure 7 is a diagram showing the circuit of the control box. - Referring now to
figures 1 and2 there is shown awork boot 10 having aheel 12 and a sole 14 along with an upper 16. As shown in the drawings, theheel 12 has aheel plate 13 that is hinged, at its forward portion, at 18 to the boot. Theheel plate 12 can pivot in a vertical plane about an axis normal to the vertical plane at thehinge 18. A flexible,impermeable bellows wall 20 defines abellows chamber 21 between the boot and the pivotingheel 12. A onewayair inlet valve 20a is defined in theflexible wall 20. - Likewise the
outsole 14a pivots about ahinge 22 in the toe region of theboot 10. Theoutsole 14 can pivot in a vertical plane about an axis at thehinge 22 that is normal to the vertical plane. A flexible,impermeable bellows wall 24 is provided defining abellows chamber 25 between the boot and the pivotingoutsole 14a. A onewayair inlet valve 25a is provided in thebellows wall 24, which otherwise is airtight. - An
air conduit 32 communicates thebellows chamber 25 with thebellows chamber 21. A one-way check valve 31 interrupts theconduit 32 to prevent the air from returning into thechamber 25. When a person weighing 180 lbs places weight on theoutsole 14a, the air in the relativelylarge bellows chamber 25 is compressed to 10-13psi. Theoutsole 14a has an area of approximately 10 in2 (65 cm2). The air then passes throughconduit 32 to the relativelysmaller bellows chamber 21. - When the weight of the user is transferred to the
heel 12, the precompressed air is now compressed to between 25-30 psi (172 kPa - 207 kPa); partly because of the smaller heel area providing asmaller chamber 21. - The compressed air from the
bellows chamber 21 passes through theconduit 28 to thereservoir 26, interrupted by a one-way check valve 30. Thereservoir 26, mounted on the side of the upper 16 of theboot 10, typically has a capacity of 12 in3 (197 cm3), in order to provide storage capacity for the compressed air before it is released to theturbine 34. - An
air conduit 36 communicates thereservoir 26 to theturbine 34. Theair conduit 36 is interrupted by apressure control valve 38. It was determined that the ideal pressure for delivering the air to theturbine 34 is between 30 and 40 psi, but the latter is preferred. - A
control panel 40 is mounted to the side of the upper 16 and preferably between inner-layers forming the upper 16. An air-line 42 extends between thevalve 38 and apressure regulator 43 on thecontrol panel 40. Thevalve 38 is opened by the pressure regulator, when the pressure threshold e.g. 40 psi is attained. - As shown in
Figs. 3a and3b , theturbine 34 may be approximately 51 mm long and less than 10 mm in diameter. The turbine is considered to be minituarised and other similar dimensions are considered to be equivalent. The criteria is that it must be able to be mounted to the upper 16 ofboot 10. Theturbine 34 is made up of atubular casing 60 enclosing acylindrical stator 70, in the form of a sleeve, with a concentric,elongated rotor 68. Therotor 68 includes acoaxial shaft 66 extending upstream and downstream thereof. Aninlet cap 62 is threaded onto theexternal threads 61 of thetubular casing 60. At the other end of thecasing 60 is anoutlet cap 64 with itexternal threads 82 adapted to engage theinternal threads 63 of thetubular casing 60. The downstream or output portion ofshaft 66 is supported by theinner race 80 of abearing 81 mounted within theoutlet cap 64. At the other end of thecasing 60, aninlet diffuser 72, in the form of a cylindrical housing, has aninner race 78, part of an integrated bearing 79, supporting the upstream end ofshaft 66. Therotor 68 mounts several stages ofrotor blades 84. Preferably eight stages are provided. Theblades 84 extend radially outwardly from the core surface of therotor 68 and are spaced apart circumferentially, equally in each stage. - The
stator 70 is fabricated in semi-cylindrical segments 70a and 70b, forming a sleeve which is mounted within thecasing 60 and is concentric with therotor 68. In certain conditions the stator may be in three segments. As shown inFigs. 6a and 6b , thestator 70 has a plurality of rows ofvanes 86, each extending radially inwardly. Thevanes 86 are spaced apart equally in each row and the rows are inter stage with the rotor stages. Back toFigs. 3a and3b we see aspring 76, within theinlet cap 62, that ensures thediffuser 72 which includes bearing 79, is precisely located, once theinlet cap 62 is threaded onto theexternal thread 61 of thecasing 60. Thediffuser 72 includes an annular array of bores 74 arranged to pass the compressed air into theturbine 34. Therotor 68 andstator 70 will be described in more detail herein below. - Returning now to
figure 2 , air entering theturbine 34 will cause theshaft 66 to rotate at an increasingly higher speed, when theshaft 66 is disengaged and rotating freely. The rotational speed of theshaft 66 is measured by an opticalangular velocity sensor 50 located in thecontrol panel 40. In the present embodiment, anoptical fiber 52 is directed to a marker on theshaft 66. The marker may be a small bore throughshaft 66. As will be described, theshaft 66 is allowed to rotate freely until it reaches a threshold sufficient to allow it to be coupled to thegenerator shaft 46. The velocity will preferably attain 90,000 rpm when the air pressure is 40 psi. Once theturbine shaft 66 is engaged with thegenerator shaft 46 the velocity thereof will decelerate.Generator 44 which is meant to convert the mechanical energy into electricity may also be used to start the rotation of the rotor. The generator would then be driven bybattery 90. - Reference will now be made to
figures 4 ,5a and 5b . A multi-stageaxial turbine 34, used to extract the available energy stored in thepressurized storage tank 26, is designed to transform the energy stored in terms of pressure and temperature into electrical energy. - For a standard axial turbine with a rotor designed in such a way that the exit velocity at all stages is oriented in the axial direction, the ideal specific work per stage (work per unit mass) is given by wt = Ut Vθ1, Ut being the tangential velocity of the rotor at the mid-radius (Rt) and Vθ1 being the tangential velocity of the airflow at the blade leading edge. The energy extracted by a turbine equipped with Vθ1 stages is then (assuming, in this simplified case, that each stage produces the same amount of work):
-
- The tangential velocity of the airflow is a high value but is limited by the speed of sound at standard ambient temperature. It is also limited by the need to keep frictional losses as low as possible.
- The mass flow rate is assumed to be constant as the available mass of air stored in the
tank 26 discharges very quickly through theturbine 34. The duration of the constant velocity period is very short and what is observed is rather a regime of acceleration followed by a deceleration time. -
Figure 5a and 5b show a schematic view of the preferred turbine geometry. The turbine geometry is characterized by the following elements: the number of stages, the blade section at each stage, the mid-radius, the angle of attack and the trailing-edge angle of the rotor blades and the stator vanes. Moreover, one must consider the rotational speed N of the turbine as another important parameter. This parameter is related to the tangential velocity of the blade at the mid-radius by: - The radius of the rotor hub is R1 while the rotor tip is R3. The radius of the inner rim of the stator is R4 while the stator vane tip is R2. It has been shown that clearances, defined by the distance between the stator vane tips and the rotor hub R2-R1 and the distance between the rotor blade tips and the stator rim R4-R3, should be kept as small as possible. Thus, the air leakage from one stage to another is minimized. The optimum design was manufactured with clearance R2-R1 of 0.120 mm and clearance R4-R3 of 0.100 mm.
-
-
- The
turbine 36 has been manufactured with α1 = 86° and β2 = 35°. The blade height of the rotor varies from 0.692 mm atstage 1 to 1.004 mm at stage 8. - The number of stages should be as low as possible to limit the manufacturing difficulties, but high enough to limit tangential velocity of the air flow. The 8-
stage turbine assembly 34 is shown inFig. 6a, 6b and6c . Therotor blades 84 are shown extending radially from therotor 68 while thestator vanes 86 are shown extending radially inwardly from the inner periphery of thestator 70. - Other factors affecting the turbine performance is the temperature inside the
storage tank 26 as well as the pressure and density. There is a pressure drop across each stage as a result of a temperature drop across the stages. To evaluate the pressure drop at each stage, a polytropic expansion is considered. For an ideal gas, the exit pressure at a given stage i is determined by: - The inlet temperature Ti
i and exit temperature Tei at stage i exhibits a temperature drop, such that there is, according to the above equation, a pressure drop and an air density drop across the stages of the turbine. This results in an increase of the turbine exit airflow. -
-
-
- This determines the small flow area as a result of the small rotor radius parameters added to the high tangential velocity of the air flow and the small available mass of air.
- The
turbine 34 has been manufactured by rapid prototyping using Multi Jet Modeling technique (MJM 3D printer from 3D Systems). CNC can also be used. - Referring now to
Fig. 2 and7 there is shown a diagram of the circuit. Theair valve 38 is open and closed by an electronic switch 38a controlled by aCPU 88 in response to thepressure sensor 43. As previously described, the pressurized air from thestorage tank 26 is passed to theturbine 34 only when the pressure threshold has been met, as determined by theCPU 88. In one example, the threshold is determined to be 40 psi. The pressurized air enters theturbine 34 to rotate therotor 68 to a high velocity, in the range of 100,000 rpm. The shaft velocity is measured by the opticalangular velocity sensor 50 and the information is sent to theCPU 88. - The
shaft 66 of theturbine 34 is coupled to thegenerator 44 only when a shaft speed threshold has been attained e.g. 90,000 rpm. TheCPU 88 sends a signal toON switch 54 in order to engage theshaft 66 to thegenerator shaft 46. Thegenerator 44 will generate electrical energy which can be stored inbattery 90. As shown infigure 7 , therotor 68 may be initially rotated by electrical current supplied from thebattery 90. The inertia of therotating rotor 68 facilitates the acceleration of the rotor to its threshold velocity by the compressed air. - The nature of the pumping process and the need to constantly accelerate and decelerate, the
generator shaft 46 causes a pulsing of the electrical current produced by thegenerator 44. As shown infigure 7 , aregulator 92 may be provided for averaging the current flow to thebattery 90 by way of a charger. -
- cv
- = specific heat at constant volume [J/kg K]
- cp
- = specific heat at constant pressure [J/kg K]
- Ef
- = energy losses due to friction [J]
- ET
- = energy extracted by the turbine [J]
- Ia
- = moment of inertia [kg m2]
- mT
- = storage tank air mass [kg]
- N
- = rotational speed [rpm]
- PT
- = storage tank air pressure [Pa]
- patm
- = atmospheric air pressure [Pa]
- R
- = ideal-gas constant for air (R = cp - cv ) [J/kg K]
- Tatm
- = atmospheric air temperature [K]
- TT
- = storage tank air temperature [K]
- VT
- = storage tank volume [m3]
- W
- = work [J]
- W
- = power [W]
- ϕ
- = energy (useful energy) [J]
- ρ T
- = storage tank air density [kg/m3]
- ρ atm
- = atmospheric air density [kg/m3]
- ω
- = angular velocity [rad/s]
Claims (15)
- A footwear energy harvesting system comprising a first gaseous pump formed at the sole of the footwear; a second gaseous pump formed at the heel of the footwear; a reservoir mounted to the upper of footwear in fluid communication with and downstream of the first and second pumps and adapted to receive pressurized gas exiting from the pumps; a turbine having an output shaft, mounted on the footwear upper, in fluid communication with and downstream of the reservoir; the turbine including an inlet port section for receiving the pressurized gas from the reservoir, when a predetermined pressure threshold is attained, so as to activate the turbine; and an electrical generator mounted on the upper, downstream of the turbine and disengageably connected with the turbine output shaft so that the generator is engaged by the shaft when a predetermined shaft velocity threshold has been attained whereby electricity may be generated in order to energize or be stored by a device worn by the bearer of the footwear.
- The footwear energy harvesting system as defined in claims 1 wherein the pressurized gas from the first pump is communicated to the second pump to pre-pressurize the gas to the second pump and the second pump communicates the pressurized gas to the reservoir.
- The footwear energy harvesting system as defined in claims 1 or 2 wherein the first gaseous pump formed at the sole of the footwear includes an outersole hinged to the forward part of the sole and includes an impermeable bellows wall defining a first pump chamber, and an inlet one-way valve for allowing air into the first pump chamber; and, the second gaseous pump includes a heel portion hinged to the forward part of the heel and includes an impermeable bellows wall defining a second pump chamber, and an inlet one-way valve for allowing air into the second pump chamber.
- The footwear energy harvesting system as defined in claims 1, 2 or 3 wherein a one way valve is provided in a gas conduit providing fluid communication between the reservoir and the turbine inlet port section, the valve is controlled by a pressure regulator to open and close the valve to control the debit of pressurized gas to the turbine.
- The footwear energy harvesting system as defined in any one of claims 1 to 4 wherein the predetermined pressurized gas threshold is selected between 30 psi (207 kPa) and 40 psi (276) kPa).
- The footwear energy harvesting system as defined in any one of claims 1 to 5 wherein a rotary speed detector is provided to determine the speed of the turbine output shaft; the speed detector is in communication with an on/off switch means to engage or disengage the generator from the output shaft whereby the generator is engaged only when the output shaft speed is above a predetermined speed threshold.
- The footwear energy harvesting system as defined in claim 6 wherein the output shaft speed threshold is 90,000 rpm.
- The footwear energy harvesting system as defined in any one of claims 1 to 7 wherein the turbine is a miniaturised, multistage axial turbine with concentric rotor and stator.
- The footwear energy harvesting system as defined in any one of claims 1 to 8 wherein the turbine includes a casing with dimensions compatible with being mounted on the upper of a boot.
- The footwear energy harvesting system as defined in claims 4 wherein the pre-pressurized air from the first bellows pump enters the second bellows pump and is compressed to 25- 30 psi (172 kPa - 207 kPa) upon a person shifting its weight to the heel.
- The footwear energy harvesting system as defined in any one of claims 1 to 10 wherein the reservoir has a volume capacity of 12 in3 (197 cm3).
- A method of harvesting energy from footwear comprising the steps of compressing a gas in a chamber at the sole of the footwear; transferring the compressed gas to a second chamber at the heel of the footwear; further compressing the gas in the second chamber; transferring the compressed gas from the second chamber to a reservoir; repeating the compression steps until the pressure in the reservoir has reached a threshold level; once the pressure level in the reservoir has reached the threshold level, passing the pressurized gas through a turbine to convert the energy from the pressurized gas to mechanical energy by rotating the turbine rotor and dependent shaft to reach a speed threshold; once the speed threshold of the shaft has been reached, engaging the shaft with an electric generator; storing the electricity and/or driving a device carried by the bearer of the footwear.
- The method as defined in claim 12 wherein the pressure threshold is 40 psi and the speed threshold is 90,000 psi.
- The method as defined in claim 12 or 13 wherein the turbine is an axial turbine and the pressurized gas is fed through the inlet of the axial turbine to rotate an elongated rotor that is concentric with a cylindrical stator causing the rotor to rotate at speeds exceeding 100,000 rpm.
- The method as defined in claims 12, 13 or 14 wherein the gas is air.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201461990942P | 2014-05-09 | 2014-05-09 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2941971A1 true EP2941971A1 (en) | 2015-11-11 |
Family
ID=53188868
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15166787.0A Withdrawn EP2941971A1 (en) | 2014-05-09 | 2015-05-07 | Footwear energy harvesting apparatus and method |
Country Status (3)
Country | Link |
---|---|
US (1) | US20150320137A1 (en) |
EP (1) | EP2941971A1 (en) |
CA (1) | CA2890703A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10973276B2 (en) * | 2017-01-23 | 2021-04-13 | Massachusetts Institute Of Technology | Energy harvesting footwear comprising three compressible volumes |
KR101931026B1 (en) | 2017-10-17 | 2018-12-19 | 한양대학교 산학협력단 | Energy harvesting shoes comprising switch |
US10512297B2 (en) * | 2018-02-20 | 2019-12-24 | Vassilios Vamvas | Electrical power generation footwear |
Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1506282A (en) | 1924-08-26 | Joseph bapybieei | ||
US4674199A (en) | 1986-04-07 | 1987-06-23 | Nikola Lakic | Shoe with internal foot warmer |
US4736530A (en) | 1987-02-17 | 1988-04-12 | Nikola Lakic | Shoe with heat engine and reversible heat engine |
US4782602A (en) | 1987-05-26 | 1988-11-08 | Nikola Lakic | Shoe with foot warmer including an electrical generator |
US4845338A (en) | 1988-04-04 | 1989-07-04 | Nikola Lakic | Inflatable boot liner with electrical generator and heater |
US4941271A (en) | 1988-08-11 | 1990-07-17 | Nikola Lakic | Boot with frictional heat generator and forced air circulation |
US5167082A (en) | 1991-09-05 | 1992-12-01 | Chen Shi Hiu | Dynamoelectric shoes |
US5367788A (en) | 1993-12-16 | 1994-11-29 | Chen; Shi-Hiu | Shoe with a built-in cooling apparatus |
US5495682A (en) | 1995-03-01 | 1996-03-05 | Chen; Shi-Hiu | Dynamoelectric shoes |
US6201314B1 (en) | 1998-04-28 | 2001-03-13 | Norman Landry | Shoe sole with liquid-powered electrical generator |
US6239501B1 (en) * | 1998-05-26 | 2001-05-29 | Robert Komarechka | Footwear with hydroelectric generator assembly |
US6255799B1 (en) | 1998-12-30 | 2001-07-03 | The Johns Hopkins University | Rechargeable shoe |
US6281594B1 (en) | 1999-07-26 | 2001-08-28 | Ivan Marijan Sarich | Human powered electrical generation system |
WO2009048872A1 (en) * | 2007-10-08 | 2009-04-16 | University Of Connecticut | Method and apparatus for generating electricity while a user is moving |
US7956476B2 (en) | 2006-12-01 | 2011-06-07 | Honeywell International Inc. | Footwear energy harvesting system |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09310A (en) * | 1995-06-16 | 1997-01-07 | World Koopo:Kk | Insole for preventing stinking of shoes |
US5655315A (en) * | 1996-08-13 | 1997-08-12 | Mershon; Randolph J. | Shoe with inflatable height-adjustment cushion |
US6182378B1 (en) * | 1998-06-10 | 2001-02-06 | Musoke H. Sendaula | Low profile pneumatic electric generator integrated in a midsole of a shoe |
US6948919B2 (en) * | 2002-12-10 | 2005-09-27 | Ingersoll-Rand Energy Systems Corporation | Hermetic motor and gas booster |
US7005757B2 (en) * | 2003-02-18 | 2006-02-28 | Shunmugham Rajasekara Pandian | Pneumatic human power conversion system based on children's play |
US7409780B2 (en) * | 2003-07-21 | 2008-08-12 | Reebok International Ltd. | Bellowed chamber for a shoe |
US6897578B1 (en) * | 2003-12-08 | 2005-05-24 | Ingersoll-Rand Energy Systems Corporation | Integrated microturbine gearbox generator assembly |
US7409779B2 (en) * | 2005-10-19 | 2008-08-12 | Nike, Inc. | Fluid system having multiple pump chambers |
TR200706912A2 (en) * | 2007-10-08 | 2009-02-23 | �Zt�Rk T�Rketap | A hydromechanical shoe. |
CA2760690A1 (en) * | 2008-05-05 | 2009-11-12 | Joshua Waldhorn | Turbine driven by predetermined deflagration of anaerobic fuel and method thereof |
US8967590B2 (en) * | 2010-03-02 | 2015-03-03 | Westlock Controls Corporation | Micro-power generator for valve control applications |
TW201215765A (en) * | 2010-10-13 | 2012-04-16 | Nat Univ Tsing Hua | Micro turbine |
US8851839B2 (en) * | 2011-08-23 | 2014-10-07 | Charles Franklin ECKART | Wide blade multiple generator wind turbine |
US9752832B2 (en) * | 2012-12-21 | 2017-09-05 | Elwha Llc | Heat pipe |
US9359992B2 (en) * | 2013-03-08 | 2016-06-07 | Ologn Technologies Ag | Systems, methods and apparatuses for harvesting power generated in a footwear |
-
2015
- 2015-05-06 CA CA2890703A patent/CA2890703A1/en not_active Abandoned
- 2015-05-07 EP EP15166787.0A patent/EP2941971A1/en not_active Withdrawn
- 2015-05-08 US US14/707,020 patent/US20150320137A1/en not_active Abandoned
Patent Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1506282A (en) | 1924-08-26 | Joseph bapybieei | ||
US4674199A (en) | 1986-04-07 | 1987-06-23 | Nikola Lakic | Shoe with internal foot warmer |
US4736530A (en) | 1987-02-17 | 1988-04-12 | Nikola Lakic | Shoe with heat engine and reversible heat engine |
US4782602A (en) | 1987-05-26 | 1988-11-08 | Nikola Lakic | Shoe with foot warmer including an electrical generator |
US4845338A (en) | 1988-04-04 | 1989-07-04 | Nikola Lakic | Inflatable boot liner with electrical generator and heater |
US4941271A (en) | 1988-08-11 | 1990-07-17 | Nikola Lakic | Boot with frictional heat generator and forced air circulation |
US5167082A (en) | 1991-09-05 | 1992-12-01 | Chen Shi Hiu | Dynamoelectric shoes |
US5367788A (en) | 1993-12-16 | 1994-11-29 | Chen; Shi-Hiu | Shoe with a built-in cooling apparatus |
US5495682A (en) | 1995-03-01 | 1996-03-05 | Chen; Shi-Hiu | Dynamoelectric shoes |
US6201314B1 (en) | 1998-04-28 | 2001-03-13 | Norman Landry | Shoe sole with liquid-powered electrical generator |
US6239501B1 (en) * | 1998-05-26 | 2001-05-29 | Robert Komarechka | Footwear with hydroelectric generator assembly |
US6255799B1 (en) | 1998-12-30 | 2001-07-03 | The Johns Hopkins University | Rechargeable shoe |
US6281594B1 (en) | 1999-07-26 | 2001-08-28 | Ivan Marijan Sarich | Human powered electrical generation system |
US7956476B2 (en) | 2006-12-01 | 2011-06-07 | Honeywell International Inc. | Footwear energy harvesting system |
WO2009048872A1 (en) * | 2007-10-08 | 2009-04-16 | University Of Connecticut | Method and apparatus for generating electricity while a user is moving |
Also Published As
Publication number | Publication date |
---|---|
CA2890703A1 (en) | 2015-11-09 |
US20150320137A1 (en) | 2015-11-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2941971A1 (en) | Footwear energy harvesting apparatus and method | |
Peirs et al. | Development of an axial microturbine for a portable gas turbine generator | |
RU2462607C2 (en) | Assistance device for transient acceleration and braking phases | |
CN201062593Y (en) | Pump and liquid supplying apparatus | |
CN208474196U (en) | Turbo-compressor | |
EP2884047B1 (en) | Compressor or turbine with back-disk seal and vent | |
US7808158B1 (en) | Flow driven piezoelectric energy harvesting device | |
US9782881B2 (en) | Device for transmitting energy to a fastener | |
CN105829728B (en) | The pressure charging system of multi-stage motor centrifugal compressor and internal combustion engine | |
JP2009133310A (en) | Air-oil separator | |
EP1122441A3 (en) | Inline pump | |
TW201033469A (en) | Multiple inlet vacuum pumps | |
US10512297B2 (en) | Electrical power generation footwear | |
EP3848568A1 (en) | Oil supply device for aircraft gas turbine | |
CN107454927B (en) | Machines equipped with air compressors or water pumps | |
US20200102894A1 (en) | Anti-surge and relight system | |
JP6826598B2 (en) | A device for storing kinetic energy | |
JP2008069681A (en) | Side channel pump and fuel battery | |
EP3058182A1 (en) | Sealing clearance control in turbomachines | |
JP6442914B2 (en) | Turbo pump | |
KR102553634B1 (en) | Pumps and methods for pumping fluids | |
BRPI0617523A2 (en) | rotor for one rotary machine and one rotary machine | |
US20110041719A1 (en) | Inertial Accumulator (IA) for onboard power supply of spinning and non-spinning projectiles and Directed Energy Projectiles | |
ES2267033T3 (en) | COMPRESSOR FOR CARS. | |
US6558131B1 (en) | Liquid ring pumps with automatic control of seal liquid injection |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
17P | Request for examination filed |
Effective date: 20160511 |
|
RBV | Designated contracting states (corrected) |
Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
R17P | Request for examination filed (corrected) |
Effective date: 20160511 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20171201 |