WO2016137096A1

WO2016137096A1 - Device for harvesting hybrid energy of heat and vibration using smart material

Info

Publication number: WO2016137096A1
Application number: PCT/KR2015/013432
Authority: WO
Inventors: 이동건; 김윤철; 이동렬; 이승찬
Original assignee: 한국산업기술대학교산학협력단
Priority date: 2015-02-23
Filing date: 2015-12-09
Publication date: 2016-09-01
Also published as: KR20160102772A; KR101714368B1

Abstract

Disclosed is a device for harvesting hybrid energy, according to an embodiment of the present invention, comprising: a resilient beam that includes a piezoelectric member and a non-magnetic resilient material that are bonded to each other; a ferromagnetic body inserted into the resilient beam to deform the shape of the resilient beam while reciprocating between a heat source and a cooling source; a fixing support means provided on one side of the resilient beam to fix the resilient beam; and a simple support means provided on an opposite side of the resilient beam to support the resilient beam and to allow the resilient beam to rotate, wherein the piezoelectric member produces electrical energy when the shape of the resilient beam is deformed by the reciprocating of the ferromagnetic body. Further, the device for harvesting hybrid energy, according to the embodiment of the present invention, can produce electrical energy using external vibration by adjusting the natural frequency of the resilient beam using a proof mass member installed on the resilient beam.

Description

Heat and vibration hybrid energy harvesting device using smart material

The present invention relates to a thermal and vibration hybrid energy harvesting device using a smart material. More specifically, the present invention relates to a hybrid energy harvesting device for converting heat and vibration energy into electrical energy using a smart material.

Recently, the development of the Internet of Things (ioT) technology is expected to increase the use of the wireless sensor system (WSN). In order to improve the reliability of the wireless sensor, energy harvesting technology has attracted attention as a method of providing power to the wireless sensor.

Energy Harvesting is a technology that converts many types of unutilized microenergy sources in our natural environment, such as vibration, heat, temperature changes, and light, into useful electrical energy. In particular, heat energy harvesting technology converts waste heat generated in industrial sites, buildings, automobile engines, and the like to heat energy of portable electronic devices such as smartphones and laptops, and micro heat of the human body as energy sources.

In the future, the demand for wireless sensors is expected to increase significantly, and thus, an efficient hybrid type technology for converting multiple energy sources into electrical energy is required.

Heat and vibration hybrid energy harvesting apparatus using a smart material according to an embodiment of the present invention aims to improve the efficiency of thermoelectric conversion.

In addition, the heat and vibration hybrid energy harvesting apparatus using a smart material according to an embodiment of the present invention aims to convert not only thermal energy but also vibration energy into electrical energy.

Hybrid energy harvesting apparatus according to an embodiment of the present invention,

An elastic beam composed of a piezoelectric member and an elastic member joined to each other; A ferromagnetic material inserted into the elastic beam to reciprocate between a heat source and a cooling source and deform the shape of the elastic beam; Fixed support means for fixing the elastic beam at one side of the elastic beam; And simple supporting means for supporting the elastic beam on the other side of the elastic beam, wherein the piezoelectric member may produce electrical energy when the shape of the elastic beam is deformed by the reciprocating movement of the ferromagnetic material.

The heat source is located in the first direction of the elastic beam, the cooling source is located in the second direction of the elastic beam, the hybrid energy harvesting device, the magnet located in the first direction of the elastic beam It may further include.

The ferromagnetic material may be attached to the magnet when the temperature of the ferromagnetic material is less than or equal to a predetermined temperature, and may be separated from the magnet when the temperature of the ferromagnetic material exceeds the predetermined temperature.

The elastic beam is deformed by the magnetic attraction between the ferromagnetic material and the magnet, and can be restored to its original shape by the elastic force when the ferromagnetic material is dropped from the magnet.

The hybrid energy harvesting apparatus may further include a proof mass member positioned at an end of the upper surface of the elastic beam.

The hybrid energy harvesting apparatus further includes vibration force applying means for applying a vibration force to the elastic beam, wherein the piezoelectric member may produce electrical energy when the shape of the elastic beam is deformed by the vibration force. have.

The hybrid energy harvesting apparatus further includes a proof mass member positioned on an upper surface of the elastic beam, and the weight of the proof mass member is adjusted, so that the vibration force of the natural frequency corresponding to the external environmental frequency is adjusted. This may be applied to the elastic beam.

The ratio a / L of the length a between the fixed support means and the ferromagnetic material to the length L between the fixed support means and the simple support means may be between 0.5 and 0.65.

Heat and vibration hybrid energy harvesting apparatus using a smart material according to an embodiment of the present invention can improve the efficiency of thermoelectric conversion.

In addition, the heat and vibration hybrid energy harvesting apparatus using a smart material according to an embodiment of the present invention can convert not only thermal energy but also vibration energy into electrical energy.

1 is a view showing the configuration of a hybrid energy harvesting apparatus according to an embodiment of the present invention.

2 is a graph for explaining the characteristics of the ferromagnetic material.

3a and 3b are views for explaining the operation of the hybrid energy harvesting apparatus according to an embodiment of the present invention.

4 is a view for explaining another operation of the hybrid energy harvesting apparatus according to an embodiment of the present invention.

5 is a view for explaining another operation of the hybrid energy harvesting apparatus according to an embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

1 is a view showing the configuration of a hybrid energy harvesting apparatus 100 according to an embodiment of the present invention.

Referring to FIG. 1, a hybrid energy harvesting apparatus 100 according to an embodiment of the present invention includes an elastic beam 110, a ferromagnetic material 120, fixed support means 130, and simple support means 140. .

The elastic beam 110 is composed of a piezoelectric member 112 and a non-magnetic elastic member 114 bonded to each other. The piezoelectric member 112 produces electrical energy when stress or strain is applied. The piezoelectric member 112 may include, for example, PZT or PVDF. As will be described later, the elastic member 114 is changed in shape according to the reciprocating movement of the ferromagnetic material 120. The nonmagnetic elastic member 114 may include metal (CuBe, etc.), rubber, silicon, and the like, but is not limited thereto.

The ferromagnetic material 120 is inserted into the elastic beam 110. The ferromagnetic material 120 has a characteristic change around a predetermined temperature (Curie temperature). Specifically, as shown in FIG. 2, the ferromagnetic material 120 has a ferromagnetic property when the temperature of the ferromagnetic material 120 is less than or equal to a predetermined temperature, and has a paramagnetic property when the temperature of the ferromagnetic material 120 exceeds a predetermined temperature. . The ferromagnetic material 120 according to the present invention may include Gd (Gadolinium).

The fixed support means 130 fixes the elastic beam 110 at one side of the elastic beam 110. The fixed support means 130 may fix the elastic beam 110 under the elastic beam 110.

The simple supporting means 140 supports the elastic beam 110 at the other side of the elastic beam 110. Unlike the fixed support means 130, the simple support means 140 does not fix the elastic beam 110, but simply supports the elastic beam 110 under the elastic beam 110 so that the elastic beam 110 may rotate. To be able.

1, a cooling source 170 may be positioned in an upper direction of the elastic beam 110, and a heat source 150 may be positioned in a lower direction of the elastic beam 110. In addition, the magnet 160 is positioned in the downward direction of the elastic beam 110. In some embodiments, the cooling source 170 may be located in the lower direction of the elastic beam 110, and the heat source 150 may be located in the upper direction of the elastic beam 110. In this case, the magnet 160 may be located in the upper direction of the elastic beam 110. For example, the heat source 150 may include the skin of the human body, and the cooling source 170 may include an air-cooled cooling device.

The temperature of the cooling source 170 may be lower than the Curie temperature of the ferromagnetic material 120, and the temperature of the heat source 150 may be higher than the Curie temperature of the ferromagnetic material 120. The heat source 150 and the cooling source 170 according to the present invention may refer to a high temperature region higher than a predetermined temperature and a low temperature region lower than a predetermined temperature, rather than a separate device that applies heat or deprives heat.

The ferromagnetic material 120 is attached to the magnet 160 in accordance with the change in its temperature and then falls off and repeats the reciprocating movement between the heat source 150 and the cooling source 170, the piezoelectric member 112 is a ferromagnetic material 120 When the shape of the elastic beam 110 is deformed by the reciprocating movement of), electrical energy is produced.

In addition, the elastic beam 110 so that the distance that the ferromagnetic material 120 moves from the cooling source 170 to the magnet 160 and the distance that the ferromagnetic material 120 moves from the magnet 160 to the cooling source 170 are the same. The position or height of can be adjusted. This is because the displacement of the piezoelectric member 112 becomes constant when the gap distance is the same, so that the magnitude of the voltage generated accordingly may be substantially constant.

3A and 3B are views for explaining the operation of the hybrid energy harvesting apparatus 100 according to an embodiment of the present invention.

When the Curie temperature of the ferromagnetic material 120 is higher than room temperature, as shown in FIG. 3A, the ferromagnetic material 120 may be initially attached to the magnet 160 according to magnetic attraction with the magnet 160. In this case, the shape of the elastic beam 110 may be deformed to the maximum. When the ferromagnetic material 120 is heated from the heat source 150 so that the temperature of the ferromagnetic material 120 exceeds the Curie temperature, as shown in FIG. 3B, an elastic beam (rather than the magnetic attraction between the ferromagnetic material 120 and the magnet 160) may be used. As the elastic force of the 110 becomes stronger to separate the ferromagnetic material 120 and the magnet 160, the ferromagnetic material 120 is attached to the cooling source 170. Again, when the ferromagnetic material 120 is cooled by the cooling source 170 and the temperature of the ferromagnetic material 120 falls below the Curie temperature, the ferromagnetic material 120 is attached to the magnet 160 as shown in FIG. 3A.

As described above, the fixed support means 130 fixes the elastic beam 110, while the simple support means 140 simply supports the elastic beam 110, so that the elastic support 110 is elastic according to the reciprocating movement of the ferromagnetic material 120. The shape of the beam 110 can be easily modified.

Meanwhile, in order for the harvesting device 100 according to an embodiment of the present invention to produce a large amount of electrical energy, the reciprocating movement period of the ferromagnetic material 120 should be short. Power generated by the piezoelectric member 112 may be expressed by the following equation.

P denotes the amount of power produced by the piezoelectric member 112, C denotes the capacitance of the piezoelectric member 112, V denotes the voltage generated by the piezoelectric member 112, and f denotes the moving frequency of the ferromagnetic material 120.

Looking at the above equation, in order for the piezoelectric member 112 to produce a large amount of power, the moving frequency of the ferromagnetic material 120 must be large. In other words, the ferromagnetic material 120 has to move quickly between the heat source 150 and the cooling source 170. For this purpose, the energy harvesting device 100 according to an embodiment of the present invention is fixed support means 130 and The distance a between the ferromagnetic bodies 120 is adjusted, and a proof mass member is positioned at the end of the upper surface of the elastic beam 110.

Referring again to FIG. 1, when the distance between the fixed support means 130 and the simple support means 140 is L, and the distance between the fixed support means 130 and the ferromagnetic material 120 is a, The ratio of a may be 0.5 to 0.65. This is to contact the ferromagnetic material 120 in parallel with the magnet 160 or the cooling source 170. If the ferromagnetic material 120 and the magnet 160 or the ferromagnetic material 120 and the cooling source 170 are not in parallel contact (that is, the surface of the ferromagnetic material 120 and the surface of the cooling source 170 or the magnet 160) ) And only a part of the ferromagnetic material 120 comes into contact with the magnet 160 or the cooling source 170. As a result, the contact area is small so that heat transfer is efficient. Will not occur.

When the shape of the elastic beam 110 is not deformed, the ferromagnetic material 120 is ideally positioned at the intermediate point between the fixed support means 130 and the simple support means 140, as shown in Figure 3a, the elastic beam 110 ) Is deformed, the ferromagnetic material 120 is fixed support means 130 in this case because the actual length of the elastic beam 110 located between the fixed support means 130 and the simple support means 140 increases. It is preferred to be located away from the intermediate point of the simple supporting means 140 toward the simple supporting means 140. Therefore, when the ratio of a to L is 0.5 to 0.65, the power output can be greatly increased.

In addition, referring back to FIG. 1, the hybrid energy harvesting apparatus 100 according to an embodiment of the present invention may further include a proof mass member 180 positioned on an upper surface of the elastic beam 110. The proof mass member 180 also serves to increase the moving speed of the ferromagnetic material 120. As described above with reference to FIGS. 3A and 3B, at room temperature, the ferromagnetic material 120 and the magnet 160 are attached to each other, and the ferromagnetic material 120 has a higher temperature, so that the ferromagnetic material 120 is attached to the cooling source 170. When trying to be, the proof mass member 180 exerts a force in the downward direction, so that the moving speed of the ferromagnetic material 120 from the heat source 150 to the cooling source 170 can be increased.

Hybrid energy harvesting apparatus 100 according to an embodiment of the present invention by increasing the moving speed of the ferromagnetic material 120 in a variety of ways, it can significantly increase the production of electrical energy.

4 is a view for explaining another operation of the harvesting apparatus 100 according to an embodiment of the present invention.

Hybrid harvesting apparatus 100 according to an embodiment of the present invention may produce electrical energy using a vibration force applied from the external environment. 4, the harvesting apparatus 100 according to an embodiment of the present invention may further include a vibration force applying means 190. The vibration force applying means 190 may include, for example, a motor, but is not limited thereto.

The vibration force applying means 190 applies a vibration force to the elastic beam 110 to cause the elastic beam 110 to vibrate like R. In this case, the vibration force applying means 190 may apply the vibration force of the frequency corresponding to the natural frequency of the proof mass member 180 to the elastic beam 110 to maximize the shape deformation of the elastic beam 110 through resonance. Can be. When the shape of the elastic beam 110 is deformed by the vibration force, the piezoelectric member 112 may produce electric energy corresponding to the degree of deformation.

According to the embodiment, as shown in FIG. 5, the vibration force applying means 190 may not be included in the hybrid energy harvesting apparatus 100. The hybrid energy harvesting apparatus 100 included in the wireless sensor may generate electrical energy by using the generated vibration when vibration occurs according to the movement of the wireless sensor, and the proof mass member 180 may be elastic by vibration. The shape of the beam 110 may be better modified. In this case, by adjusting the weight of the proof mass member 180, the vibration force of the natural frequency corresponding to the external environmental frequency may be applied to the elastic beam 110.

Heat and vibration hybrid energy harvesting apparatus 100 using a smart material according to an embodiment of the present invention can improve the efficiency of thermoelectric conversion, it is possible to convert not only thermal energy but also vibration energy into electrical energy.

On the other hand, the embodiments of the present invention described above are implemented as a semi-permanent power supply of the wireless sensor for the Internet of Things or wearable equipment by utilizing the unutilized heat of industrial equipment, buildings, vehicles and human body and the abandoned vibration source by operating the device. Can be.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. You will understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

An elastic beam composed of a piezoelectric member and an elastic member joined to each other;

A ferromagnetic material inserted into the elastic beam to reciprocate between a heat source and a cooling source and deform the shape of the elastic beam;

Fixed support means for fixing the elastic beam at one side of the elastic beam; And

Simple support means for supporting the elastic beam on the other side of the elastic beam,

The piezoelectric member is a hybrid energy harvesting device, characterized in that for producing the electrical energy when the shape of the elastic beam is deformed by the reciprocating movement of the ferromagnetic material.
The method of claim 1,

The heat source is located in the first direction of the elastic beam, the cooling source is located in the second direction of the elastic beam,

The hybrid energy harvesting device,

And a magnet located in the first direction of the elastic beam.
The method of claim 2,

The ferromagnetic material,

And the ferromagnetic material is attached to the magnet when the temperature of the ferromagnetic material is less than or equal to a predetermined temperature, and falls from the magnet when the temperature of the ferromagnetic material exceeds the predetermined temperature.
The method of claim 3,

The elastic beam,

The shape is deformed by the magnetic attraction between the ferromagnetic material and the magnet, the hybrid energy harvesting device, characterized in that the ferromagnetic material is restored to its original shape by the elastic force when dropped from the magnet.
The method of claim 1,

The hybrid energy harvesting device,

And a proof mass member positioned on an upper surface of the elastic beam.
The method of claim 1,

The hybrid energy harvesting device,

Further comprising vibration force applying means for applying a vibration force to the elastic beam,

The piezoelectric member,

Hybrid energy harvesting device, characterized in that for producing the electrical energy when the shape of the elastic beam is deformed by the vibration force.
The method of claim 6,

The hybrid energy harvesting device,

Further comprising a proof mass member located on the upper surface of the elastic beam,

By adjusting the weight of the proof mass member, the vibration energy of the natural frequency corresponding to the external environmental frequency is applied to the elastic beam.
The method of claim 1,

The ratio (a / L) of the length (a) between the fixed support means and the ferromagnetic material to the length (L) between the fixed support means and the simple support means is between 0.5 and 0.65. Device.