Solar power generation system

Abstract

A solar thermal power generation system is constructed using thermoelectric conversion elements that do not require a temperature difference. [Solution] A power generation system is provided that includes a heat collection tube, the heat collection tube including a thermoelectric conversion element, the thermoelectric conversion element having a flat plate shape, and the thermoelectric conversion element being housed inside the heat collection tube.

Description

[Technical field]

[0001] The present invention relates to a power generation system that uses solar heat. [Background technology]

[0002] The use of solar energy has involved the use of hot water obtained by heating water with solar heat, or the use of steam generated by heating water with solar heat to turn a turbine and generate electricity. For example, see Patent Document 1.

[0003] In addition, solar panel power generation is the mainstream for generating electricity using sunlight. When generating electricity using solar heat, the boiler method, which uses solar heat to boil water and turn a turbine, and the method of directly converting it into electricity using a thermoelectric conversion element (Peltier element) are widely used. For example, see Patent Document 3.

[0004] On the other hand, thermoelectric conversion elements that do not require a temperature difference have been invented, as shown in Patent Documents 2 and 4, and may be applicable to a variety of power generation purposes. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2012 / 042639 [Patent Document 2] Patent No. 7011361 [Patent Document 3] JP 2007-166721 A [Patent Document 4] International Publication No. 2023 / 038103 Summary of the Invention [Problem to be solved by the invention]

[0006] According to one aspect of the present invention, an object is to construct a solar thermal power generation system using a thermoelectric conversion element that utilizes heat from the sun or the like and does not require a temperature difference. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a power generation system including a heat collection tube, the heat collection tube including a thermoelectric conversion element that does not require a temperature difference, the thermoelectric conversion element having a bendable flat plate shape, and the thermoelectric conversion element being stored inside the heat collection tube by being rolled or folded. Effect of the Invention

[0008] According to one aspect of the present invention, even on cloudy days when solar heat is difficult to reach or at night when solar heat does not reach, power generation can be continued by using the heat pre-heat stored inside the heat collection tube during the day.

[0009] Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 illustrates an example of a thermoelectric power generation system according to an embodiment of the present invention. [Diagram 2] FIG. 2 shows an example of a heat collection tube used in a thermoelectric power generation system according to an embodiment of the present invention, where (a) is a cross-sectional view of the heat collection tube, and (b) shows a thermoelectric conversion element with a conducting wire connected thereto. [Diagram 3] FIG. 3 shows another example of a heat collection tube used in a thermoelectric power generation system according to an embodiment of the present invention, in which (a) is a cross-sectional view of the heat collection tube, and (b) shows a thermoelectric conversion element connected to a conductive wire. [Figure 4] FIG. 4 shows an example of a configuration in which a plurality of thermoelectric power generation systems are arranged and connected in series (a) or in parallel (b). [Diagram 5] FIG. 5 shows an example of a thermoelectric conversion element used in an embodiment of the present invention. [Figure 6] FIG. 6 shows an example of an auxiliary sheet for a thermoelectric conversion element used in an embodiment of the present invention, where (a) shows an example of the auxiliary sheet when unfolded, and (b) shows an example of the auxiliary sheet when used.

[0011] 1 shows an example of a thermoelectric power generation system according to an embodiment of the present invention. In this embodiment, a system that generates power based on solar heat will be described.

[0012] The thermoelectric power generation system 1000 of this embodiment includes a heat collection tube 100. The thermoelectric power generation system 1000 of this embodiment may additionally include a heat collector 200.

[0013] The heat collection tube 100 has a function of collecting and storing solar heat inside the heat collection tube 100 .

[0014] The heat collector 200 is, for example, a reflector plate, and is composed of an upper plate 210, a lower plate 220, and a side plate 230. At least the side plate 230 is configured in a shape capable of collecting solar heat to the heat collection tube 100 installed in the thermal power generation system 1000. Specifically, the side plate 230 is made of a material that reflects solar heat, such as a mirror or a metal plate, and is disposed in a direction that reflects the solar heat and causes it to enter the heat collection tube 100. Note that, although the side plate 230 in this embodiment is composed of multiple flat plates, it may also be composed of a single curved plate.

[0015] The thermoelectric power generation system 1000 of this embodiment may further include a lid 310, and an upper fixture 330 and a lower fixture 320 for positioning the heat collection tube 100 at a position where it can efficiently receive solar heat. The lid 310 functions as a plug for an upper opening of the heat collection tube 100. The upper fixture 330 is attached to a part of the upper plate 210, and the lower fixture 320 is attached to a part of the lower plate 220, and fixes the heat collection tube 100. In addition, a through hole may be provided in the lid 310 of the heat collection tube 100, or the lid 310 may simply be removed, allowing the solution 140 inside the thermoelectric power generation system 1000 to evaporate to the outside.

[0016] The thermoelectric power generation system 1000 of this embodiment may be configured to obtain a desired high voltage by arranging a plurality of thermoelectric power generation systems 1000 and connecting them in series as shown in Fig. 4(a), or may be configured to obtain a desired high current by connecting a plurality of thermoelectric power generation systems 1000 in parallel as shown in Fig. 4(b).

[0017] FIG. 2 shows an example of a heat collection tube used in a thermoelectric power generation system according to an embodiment of the present invention.

[0018] As shown in FIG. 2( a ), the heat collection tube 100 of this embodiment includes an outer tube 111 , an inner tube 112 , a thermoelectric conversion element 120 , and a solution 140 .

[0019] The outer tube 111 is made of glass or the like, and has a structure that transmits solar heat to the inner tube 112 . The inner tube 112 is made of glass or the like, and is subjected to a silver plating process or the like, and has a structure that reflects heat radiation from inside the inner tube 112 and keeps the heat inside. Combining the outer tube 111 and the inner tube 112 forms a structure that can store solar heat inside the heat collection tube 100. Specifically, a double-tube structure is formed having a cylindrical outer tube 111 and an inner tube 112, and a vacuum is created between the outer tube 111 and the inner tube 112. This structure makes it difficult for solar heat taken into the inside of the heat collection tube 100 to escape to the outside due to the vacuum insulation effect.

[0020] The thermoelectric conversion element 120 is, for example, a thermoelectric conversion element that does not require a temperature difference. By using a thermoelectric conversion element that does not require a temperature difference, electricity can be collected directly from solar heat. The thermoelectric conversion element 120 has a bendable flat plate shape, and is stored in the heat collection tube 100 by rolling or folding it.

[0021] The solution 140 is an optional component, but is filled into the inner tube 112 of the heat collection tube 100. By filling the inner tube 112 with the solution 140, the heat storage effect is further enhanced compared to a state in which a gas such as air is filled, and the boiling point of the solution suppresses unintended temperature increases inside the heat collection tube 100, thereby preventing damage to the thermoelectric conversion element. Furthermore, since the solar heat obtained during the day can be stored inside the heat collection tube 100, the inside of the inner tube 112 can be maintained at a high temperature even if the amount of solar heat received by the heat collection tube 100 decreases. For example, even if the amount of solar heat decreases from the evening to the night, by filling the inside of the inner tube 112 with the solution 140, the temperature inside the inner tube 112 gradually decreases, and power generation can be continued for a long period of time that exceeds the hours of sunlight. The solution 140 is one that is difficult to volatilize, has a large heat storage effect, and is low in reactivity and harmful to living organisms and the environment, and examples of such solutions include water, ethylene glycol, polyethylene glycol, alcohol-based solvents such as ethanol, methanol, propyl alcohol, isopropyl alcohol, butanol, hexanol, octanol, nonanol, decanol, tridecanol, and isopropyl alcohol, aliphatic hydrocarbons such as paraffin, olefin, naphthene, lubricating oil, edible oil, glycerin, and silicone oil. In addition, fluorine-based solutions and the like may be used as long as their biological and environmental safety can be guaranteed.

[0022] In this embodiment, a flat thermoelectric conversion element 120 is housed inside the heat collection tube 100. Unlike a system in which the area receiving light determines the output, such as a solar panel, the thermoelectric conversion element 120 can be rolled or folded and housed inside the heat collection tube 100, which makes it possible to increase the amount of power generation per unit area and make the power generation system more compact.

[0023] 2(b) shows a thermoelectric conversion element 120 to which conductors 121 and 122 are connected. Conductor 122 and conductor 121 are attached to an arbitrary location of electrode 11 and an arbitrary location of electrode 12 of thermoelectric conversion element 120, respectively. In addition, a through hole is provided in lid 310, and generated electricity can be taken out by drawing out conductors 121 and 122 to the outside through the through hole.

[0024] 3 shows another example of a heat collection tube used in a thermoelectric power generation system according to an embodiment of the present invention. Here, the differences from the heat collection tube in FIG. 2 will be described. In the cross-sectional view of the heat collection tube in Fig. 3(a), the conductor wires 121 and 122 are drawn out from the center of the thermoelectric conversion element 120. In this case, Fig. 3(b) shows the shape of the thermoelectric conversion element to which the conductor wires are connected, and is configured so that the size (area) of electrode 12 is slightly larger than the size of electrode 11. In this way, by configuring the shape of electrode 11 to be different from the shape of electrode 12, it becomes possible to draw out the conductor wires 121 and 122 from one surface.

[0025] FIG. 5 shows an example of a thermoelectric conversion element 120 that does not require a temperature difference and is used in an embodiment of the present invention.

[0026] The thermoelectric conversion element 120 includes a first electrode 11, a second electrode 12, and an intermediate portion 14. The thermoelectric conversion element 120 may include, for example, a first substrate 15. The first substrate 15 is made of a material that is flexible and insulating. The first electrode 11 and the second electrode 12 are provided facing each other. The first electrode 11 and the second electrode 12 have different work functions. As the material of each electrode 11, 12, for example, a material made of a single element such as platinum, gold, palladium, copper, iron, chromium, cobalt, titanium, nickel, aluminum, zirconium, tungsten, or carbon may be used, or, for example, an alloy made of two or more elements, and an oxide, nitride, boride, or carbide thereof may be used. For details of the thermoelectric conversion element 120 used in one embodiment of the present invention, please refer to Patent Document 2 (Japanese Patent No. 7011361).

[0027] In addition, the power generation system of this embodiment can be applied not only to the thermoelectric conversion element 120 that does not require a temperature difference shown in Patent Document 2 (Patent Publication No. 7011361) and Patent Document 4 (WO 2023 / 038103), but also to other thermoelectric conversion elements that do not require a temperature difference.

[0028] FIG. 6 shows an example of an auxiliary sheet 600 for the thermoelectric conversion element 120 used in an embodiment of the present invention. The auxiliary sheet 600 of this embodiment is composed of a thermoelectric conversion element 610 (see thermoelectric conversion element 120 in Figure 5. Thermoelectric conversion element 610 has a first substrate with an insulating function corresponding to thermoelectric conversion element 120 in Figure 5), a spacer 640, a pair of electrodes 650, and a tube 660. The spacers 640 are arranged along the width direction (horizontal direction in FIG. 6(a)) of the thermoelectric conversion element 610 and on both the upper end side and the lower end side (in FIG. 6(a)) of the thermoelectric conversion element 610. The interval between the spacers 640 may be any length, and the number and shape of the spacers 640 may also be any, as long as the spacers 640 can maintain the rolled cylindrical shape in FIG. 6(b) described later and are configured to such an extent that the outside of the thermoelectric conversion element 610 on the inside does not come into contact with the inside of the thermoelectric conversion element 610 on the outside when rolled. Furthermore, the spacers 640 may have heat resistance and waterproof properties. Although the spacer 640 in this embodiment has a through hole therein, in another embodiment, the spacer 640 may not have a through hole. The pair of electrodes 650 are connected to the conductive wires 121, 122 of the thermoelectric conversion element 610 (see FIGS. 2 and 3. The thermoelectric conversion element 610 corresponds to the thermoelectric conversion element 120 in FIGS. 2 and 3). The tube 660 has a through hole, and is configured to pass the conductive wires 121, 122 and the pair of electrodes 650 through the inside of the through hole. The tube 660 may be configured to serve as a core (center) when the auxiliary sheet 600 is rolled up.

[0029] As shown in FIG. 6(b), the auxiliary sheet 600 of this embodiment can wrap thermoelectric conversion elements 610 around the heat collection tube while ensuring water permeability and preventing contact between the thermoelectric conversion elements.

[0030] By using the auxiliary sheet 600 of this embodiment, for example, it is possible to prevent contact between the thermoelectric conversion elements 610, and by bringing the solution into contact with both sides of the thermoelectric conversion elements 610, it is possible to suppress unintended temperature increases and avoid damage to the thermoelectric conversion elements 610.

Claims

1. A power generation system including a heat collection tube, The heat collection tube includes a thermoelectric conversion element, the thermoelectric conversion element has a flat plate shape, and the thermoelectric conversion element is housed inside the heat collection tube, A power generation system, characterized in that an auxiliary sheet having spacers arranged on a thermoelectric conversion element having a first substrate with an insulating function is stored inside the heat collection tube.

2. 2. The power generation system according to claim 1, wherein the thermoelectric conversion element is a thermoelectric conversion element that does not require a temperature difference.

3. 2. The power generation system according to claim 1, wherein a material with high heat storage capacity is used inside the heat collection tube, and heat generated by sunlight during the day is stored inside the heat collection tube, thereby enabling power generation to be performed at night as well.

4. 2. The power generation system according to claim 1, further comprising a heat collector arranged to reflect sunlight to be incident on said heat collection tube.

5. 2. The power generation system according to claim 1, wherein the thermoelectric conversion element comprises a first electrode, a second electrode, and an intermediate portion between the first electrode and the second electrode, and is configured so that one conductor is drawn from an arbitrary point of the first electrode and the other conductor is drawn from an arbitrary point of the second electrode.

6. 4. The power generation system according to claim 3, wherein the material having high heat storage capacity in the heat collection tube is a solution.

7. The power generation system according to claim 6, characterized in that a plug is provided in a part of the heat collection tube, and by providing a through hole in the plug or by removing the plug, the solution can be vaporized and evaporated to the outside through the through hole.

8. A power generation system having a heat collection tube, The heat collection tube includes a thermoelectric conversion element, the thermoelectric conversion element has a flat plate shape, and the thermoelectric conversion element is housed inside the heat collection tube, A material with high heat storage capacity is used inside the heat collection tube, and heat generated by sunlight during the day can be stored inside the heat collection tube, allowing electricity to be generated at night as well. The material having high heat storage capacity in the heat collection tube is a solution, A power generation system comprising: a plug provided in a portion of the heat collection tube; and a through hole provided in the plug or the plug being removed, so that the solution can be vaporized and evaporated to the outside through the through hole.

9. A power generation system including a heat collection tube, The heat collection tube includes a thermoelectric conversion element, the thermoelectric conversion element has a flat plate shape, and the thermoelectric conversion element is housed inside the heat collection tube, A power generation system characterized in that a plug is provided in a part of the heat collection tube, and by providing a through hole in the plug or removing the plug, the solution in the heat collection tube can be vaporized and evaporated to the outside through the through hole.

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