JP4841240B2 - Lighting device - Google Patents

Description

  The present invention relates to a lighting device that generates electric energy from a thermoelectric generator using thermal energy such as geothermal heat and converts the electric energy into light energy by a light emitting element.

  General lighting devices (such as streetlights and garden lights) emit light using electrical energy transmitted from the power station. However, they are used in environments such as thermal power generation using fossil fuels and nuclear power generation that generates radioactive waste. The majority of power generation takes a load. The impact of the power generation on the global environment is becoming more serious every year, and how to reduce the amount of power generation that is burdened with the environment has become a global theme. In addition, there are problems such as energy shortage and power generation reduction due to fossil fuel depletion in the near future. Furthermore, the power transmission from the power plant has the problem of a power outage in situations such as power plant accidents, faulty transmission lines, and interruptions due to disasters.

  In order to avoid such problems of power shortage due to the future depletion of fossil fuels and global issues such as environmental destruction, we used natural energy that is friendly to the global environment rather than lighting equipment that generates power that requires current transmission lines. A self-powered lighting device is expected.

  As a power generation method using natural energy, forms using various energies such as hydropower, sunlight, tide level, wave power, and geothermal heat are known. Above all, because the Japanese archipelago is on the volcanic belt, it is easy to obtain geothermal energy.

In Patent Document 1, a thermoelectric generator such as a Peltier element that converts the temperature difference between the electrodes at both ends into electric power is installed at a place where geothermal heat is generated, and the heat absorption side electrode of the thermoelectric generator is heated to a higher temperature than the heat dissipation electrode by geothermal heat. A geothermal power generation method for obtaining electric power is disclosed.
JP 2005-137138 A

  The present invention has been made in view of the problem of power shortage due to the future depletion of fossil fuels and global issues such as environmental destruction, and an object of the present invention is to provide a self-powered lighting device using geothermal heat that is natural energy. It is said.

  In order to achieve the above object, a lighting device of the present invention includes a thermoelectric generator that generates electrical energy corresponding to a difference in thermal energy applied to both ends. One end of the thermoelectric generator is provided with a heating electrode heated by geothermal heat, and the other end of the thermoelectric generator is provided with a cooling electrode exposed to the outside air. A light emitting element that emits light upon receiving electric energy generated by the thermoelectric generator is mounted on the side of the heating side electrode opposite to the surface to be heated.

  In such a configuration, geothermal energy continuously supplied from the inside of the earth is converted into electric energy by the thermoelectric generator, and the light emitting element emits light by this electric energy.

  As the difference in thermal energy applied to both ends of the thermoelectric generator is larger, the electrical energy is larger. Therefore, a heat conductor that efficiently transmits the geothermal heat in the ground is provided on the heating side electrode, or water cooling is applied to the cooling side electrode. It is preferable to mount the cooling device.

  It is preferable to use an LED or an EL element as the light emitting element.

  The lighting device according to the present invention is self-powered / self-lighting lighting using geothermal heat, which is natural energy friendly to the global environment, and can cope with irregular situations such as power outages.

  Furthermore, the lighting device of the present invention preferably further includes a storage device that stores electrical energy generated by the thermoelectric generator, and a sensor switch that supplies the light source with the electrical energy of the storage device when dark. . According to such a configuration, the light is not emitted when the surroundings are bright such as during the day, but the electric energy generated by the thermoelectric generator is stored, and the surroundings are darkened such as at night, and light is emitted using the electrical energy. Is economical.

  Furthermore, if the heating side electrode of the thermoelectric generator is also heated by solar energy that is natural energy other than geothermal heat, an increase in illuminance can be expected.

  The effects of the present invention are as follows: 1) Current power generation can be reduced by the effective use of geothermal energy, and the lighting device according to the present invention does not require fuel, thereby reducing environmental problems such as environmental destruction and power shortage. ) Since it can always emit light without affecting power transmission from the power plant, it can be mentioned that it is effective lighting in areas where power transmission is difficult and in situations where power transmission is difficult (disasters, etc.).

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing an illumination apparatus according to Embodiment 1 of the present invention.

  The lighting device of the form shown in this figure includes an electrode A that is heated by geothermal heat. The light emitting element 1 is mounted in the center on the surface opposite to the surface to be heated of the electrode A, and one end of the thermoelectric generator 2 is connected around the light emitting element 1. An electrode B is connected to the other end of the thermoelectric generator 2 and is exposed to the outside air.

  As the thermoelectric generator 2, a semiconductor thermoelectric generator having a high thermoelectric conversion efficiency such as a Peltier element is used. Generally, a semiconductor thermoelectric generator has a structure in which an electric circuit is configured by sandwiching a semiconductor chip having P-type and N-type electrical characteristics between electrode plates having excellent heat conductivity and conductivity such as copper and nickel. In the thermoelectric generator 2 configured as described above, the heating-side electrode A is heated to a high temperature by geothermal heat, and the cooling-side electrode B is cooled to a low temperature by outside air, so that a DC thermoelectromotive force corresponding to the thermal gradient is generated. .

  The direct current voltage generated from the thermoelectric generator 2 is directly applied to the light emitting element 1. For this reason, when the thermoelectromotive force is generated by the thermoelectric generator 2, the light emitting element 1 emits light immediately.

  Since the electricity generated from the thermoelectric generator 2 is direct current, it is more efficient to use an element capable of direct current drive as the light emitting element 1, and an LED or EL (electroluminescence) element is used. In addition, by adding a circuit that controls the current of the DC drive element depending on the application, it is possible to realize additional functions such as blinking control, maintaining stable luminance, increasing the luminance peak value, and extending the element life. .

As described above, the lighting device of the present embodiment has a structure in which the thermoelectric generator 2 converts the thermal energy obtained from geothermal heat and the thermal energy difference between the outside air into a DC voltage, and can directly apply the DC voltage to the light emitting element 1. It is. The light emitting element 1 emits light with the DC voltage (electric energy). Therefore, since this lighting device uses geothermal heat, which is natural energy, it is a lighting that does not require fuel and can be said to be an ecological lighting that contributes to a reduction in CO ₂ emissions. In addition, geothermal energy is constantly supplied from the inside of the earth, so that irregular situations such as power outages are unlikely to occur.

  Further, the thermoelectric generator 2 generates larger electric energy as the difference in thermal energy applied to both ends of the thermoelectric generator 2 is larger. For this reason, a high-efficiency heat conductor is used for the heating side electrode A in order to efficiently transmit geothermal heat to the thermoelectric generator 2, or the cooling side electrode B is not only exposed to the outside air but also actively cooled by a cooling device such as water cooling. Then, the energy difference given to both ends of the thermoelectric generator 2 is changed according to the required illuminance.

  2 shows an example in which a high-efficiency thermal conductor is used for the heating side electrode A of the thermoelectric generator 2, and FIG. 3 shows an example in which a cooling device is used for the cooling side electrode B of the thermoelectric generator 2.

  In the form shown in FIG. 2, one end of the thermoelectric generator 2 is connected to the center of the surface of the electrode A opposite to the surface to be heated, and the light emitting element 1 is mounted around the thermoelectric generator 2. An electrode B is connected to the other end of the thermoelectric generator 2 and is exposed to the outside air. The DC voltage generated from the thermoelectric generator 2 is directly applied to the light emitting element 1. For this reason, when a thermoelectromotive force is generated by the thermoelectric generator 2, the light emitting element 1 emits light immediately. In this embodiment, in particular, the heat conductor 3 is bonded to the surface to be heated of the electrode A, and the portion corresponding to the thermoelectric generator 2 of the heat conductor 3 in order to efficiently transmit the geothermal heat to the thermoelectric generator 2. Protrudes in a convex shape and can be inserted into the ground.

  On the other hand, in the form shown in FIG. 3, one end of the thermoelectric generator 2 is connected to the surface opposite to the surface to be heated of the electrode A, and the electrode B is connected to the other end of the thermoelectric generator 2. The light emitting element 1 is mounted on the opposite side of the electrode B from the thermoelectric generator 2 via a cooling device 4 such as water cooling. The DC voltage generated from the thermoelectric generator 2 is directly applied to the light emitting element 1.

  2 and 3, it is possible to increase the temperature electromotive force generated by increasing the temperature gradient between the two end electrodes A and B of the thermoelectric generator 2.

  Since the lighting device of the present invention described with reference to each of the embodiments as described above is a lighting that self-powers and emits light using geothermal heat, which is natural energy, basically the installation location is not selected. However, since the lighting device according to the present invention can emit light with higher brightness as the geothermal energy is higher, it is more effective especially in hot springs, and excavation to the ground is necessary in places where geothermal energy is low. It becomes. The lighting device according to the present invention is expected to be used as auxiliary lighting in an area where energy generation as main lighting does not occur. As a specific example, an application as an embedded display board in a road or a foot auxiliary lighting in a park can be considered. In addition, since it emits light without any influence in the event of an emergency such as a lifeline shutdown that occurs in the event of a disaster, it can be effectively used as a guide light to an evacuation site. In addition, the illumination is effective even in environments where it is difficult to open commercial power (for example, mountain trails). In high geothermal energy areas (areas where the surface temperature is high), the energy conversion efficiency of thermoelectric generators generally increases, so it can be expected to be used as main lighting such as night lights.

(Other embodiments of the present invention)
Furthermore, another embodiment of the present invention will be described.

  As another embodiment, it is possible to turn on the discharge tube in place of the DC-driven light emitting element 1 such as an LED or an EL element by inputting electric energy generated in the thermoelectric generator 2 into the inverter circuit. .

  Moreover, the illumination device of each of the above embodiments may emit light when the surroundings are bright, such as during the day, and emit light when the surroundings are dark, such as at night. For example, in the lighting device of each of the above embodiments, a storage device (battery) that stores electrical energy generated by the thermoelectric generator 2 and a storage device that is less than a predetermined amount of incident light (when the surroundings become dark) It is conceivable to include a sensor switch that supplies stored electricity to the light emitting element 1. According to such an apparatus, the electrical energy obtained when it is bright can be effectively used as a drive source of the light emitting element 1 at night.

  Further, by integrating solar energy on the heating side electrode A of the thermoelectric generator 2 heated by geothermal heat during the daytime, the electric energy accumulated in the accumulator can be increased to improve the night illumination. Good.

It is a schematic diagram which shows the illuminating device of Embodiment 1 of this invention. It is a schematic diagram which shows the illuminating device of Embodiment 2 of this invention. It is a schematic diagram which shows the illuminating device of Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Thermoelectric generation element 3 Thermal conductor 4 Cooling device A Heating side electrode of thermoelectric generation element B Cooling side electrode of thermoelectric generation element

Claims (3)

A heating electrode heated by geothermal heat;
A thermoelectric generator that generates electrical energy in accordance with a difference in thermal energy applied to both ends, wherein one end is joined to one surface of the heating-side electrode ; and
A heat conductor that is bonded to the other surface of the heating side electrode and that conveys geothermal heat in the ground to the heating side electrode by projecting a portion corresponding to the thermoelectric generation element into a convex shape, and
A cooling-side electrode provided at the other end of the thermoelectric generator, exposed to the outside air, or mounted with a cooling device ;
A light emitting element that is mounted on the one surface of the heating side electrode and emits light by receiving electrical energy generated by the thermoelectric generation element;
A storage device for storing electrical energy generated by the thermoelectric generator;
A sensor switch for supplying electrical energy of the storage device to the light emitting element when darkened;
A lighting device comprising: The lighting device according to claim 1 , wherein the one surface of the heating side electrode is exposed so as to be heated by sunlight. The lighting device according to claim 1 or 2, wherein the light emitting element is an LED or an EL element.

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