JP5752511B2 - Solar thermal collector and solar thermal power generation system - Google Patents

Description

  The present invention relates to a solar heat collector that collects sunlight and collects heat to heat a thermal refrigerant, and a solar thermal power generation system including the solar heat collector.

  Development of the use of renewable energy is being promoted as a countermeasure against global warming, and some have been put into practical use. One of them is a concentrating solar power generation system (CSP). Patent Document 1 is known as this solar thermal power generation system (CSP), and an example thereof is shown in FIG.

  This concentrating solar thermal power generation system 100 includes a condensing / heat collecting system 101 in which solar heat collectors 104 are arranged, a power generating system 102, and a heat storage system 103. In the condensing / heat collecting system 101, the solar heat collector 104 collects and absorbs sunlight and converts it into heat energy (that is, heat collection) to heat the heat medium to 400 ° C. This heat medium is supplied to the steam generator 105 and superheater 106 of the power generation system 102 to generate high-temperature and high-pressure steam, and by rotating the steam turbine 107, the generator 108 is driven to generate power.

  Patent document 2 etc. are known as the solar heat collector 104 used for the condensing and heat collecting system 101 of such a solar thermal power generation system 100, and an example of the structure is shown in FIG.

The cross section of the mirror 110 has a parabolic shape, and a heat collecting pipe 111 is disposed at the focal position of the mirror 110. A light absorption layer is formed on the surface of the heat collecting pipe 111. Further, the heat collecting pipe 111 is enclosed in a glass tube 112 and insulated by vacuum. Then, the mirror 110 collects sunlight, the collected sunlight is absorbed by the heat collecting pipe 111 and converted into heat energy (heat collection), and the thermal refrigerant flowing inside the heat collecting pipe 111 is converted into 400. Heat to ° C.

  In such a solar heat collector 104, the surface area of the heat collecting pipe 111 is large, and the amount of heat leakage from the heat collecting pipe 111 increases, so a measure for reducing the amount of heat leakage is necessary. In the solar heat collector 104 of Patent Document 2, the amount of heat leakage from the heat collecting pipe 111 is reduced by vacuum insulation.

JP 2008-39367 A US Pat. No. 6,705,311

  In general, the amount of radiant heat transfer from a high-temperature object increases depending on the fourth power of the temperature of each of the high-temperature object and the low-temperature object (see the following formula (1)). For this reason, when the temperature of a high-temperature object becomes high, the amount of heat leakage due to radiation from the high-temperature object increases rapidly.

  In the solar heat collector 104 shown in FIG. 10, as the temperature of the heat collection pipe 111 that is a high-temperature object rises, the amount of heat leakage due to radiation from the heat collection pipe 111 is, for example, as shown by a curve X3 in FIG. Increases rapidly. For this reason, in the conventional solar thermal power generation system 100 provided with the solar thermal collector 104, the heat collection piping 111 must be set to a low temperature of 400 ° C. and operation with low thermal collection efficiency must be performed. The system efficiency was decreasing. A curve Y3 in FIG. 11 indicates the amount of heat received by the heat collecting pipe 111.

  An object of the present invention is made in consideration of the above-described circumstances, and provides a solar heat collector and a solar power generation system that can improve the heat collection efficiency by increasing the temperature of the heat collection pipe and can suppress the amount of heat leakage. There is.

Solar solar heat collector according to the present invention, the sunlight collecting light, and the cross section is parabolic trough parabolic mirror, while being disposed opposite to the mirror, which is focused by the mirror The solar heat collector has a heat collecting pipe that absorbs heat and collects heat and heats a heat medium flowing inside, and a translucent translucent pipe that heats the heat collecting pipe in a vacuum state. In the vacuum space between the heat collecting pipe and the light transmitting pipe , the heat insulating means is provided in the entire area opposite to the area facing the mirror, away from the heat collecting pipe and the light transmitting pipe. Is arranged.

  Moreover, the solar thermal power generation system according to the present invention is heated by the condensing / heat collecting system including a solar heat collector that collects and collects sunlight and collects heat to heat the thermal refrigerant, and the solar heat collector. In a solar thermal power generation system comprising: a heat exchanger that exchanges heat with a thermal refrigerant to generate steam; and a power generation system that includes a steam turbine that rotates by the steam generated in the heat exchanger and drives a generator. The solar heat collector is the solar heat collector according to any one of claims 1 to 9.

  According to the solar heat collector and the solar power generation system according to the present invention, since the space between the heat collecting pipe and the light transmitting pipe in the solar heat collector is a vacuum space, heat conduction and convection transfer by gas from the heat collecting pipe. Heat can be suppressed. Furthermore, since the heat insulating means is disposed in the vacuum space, heat transfer due to radiation from the heat collecting pipe can be suppressed. As a result, the amount of heat leakage from the heat collection pipe can be suppressed, and the heat collection efficiency can be improved by increasing the temperature of the heat collection pipe.

1 is a pipeline diagram showing a first embodiment of a solar thermal power generation system according to the present invention. Sectional drawing of the direction orthogonal to the axis | shaft which shows the solar-heat collector of FIG. The graph which shows the relationship between the temperature of the heat collecting piping of FIG. 2, and the amount of heat leaks. Sectional drawing of the direction orthogonal to the axis | shaft which shows the solar heat collector in 2nd Embodiment of the solar thermal power generation system which concerns on this invention. The graph which shows the relationship between the temperature of the heat collecting piping of FIG. 4, and a heat leak amount ratio. Sectional drawing of the direction orthogonal to the axis | shaft which shows the solar heat collector in 3rd Embodiment of the solar thermal power generation system which concerns on this invention. The solar-heat collector in 4th Embodiment of the solar thermal power generation system which concerns on this invention is shown, (A) is sectional drawing of the direction in alignment with an axis | shaft, (B) is sectional drawing of the direction orthogonal to an axis | shaft. The pipeline diagram which shows 5th Embodiment of the solar thermal power generation system which concerns on this invention. The pipe line figure showing an example of the conventional solar thermal power generation system. Sectional drawing of the direction orthogonal to the axis | shaft which shows the conventional solar heat collector. The graph which shows the relationship between the temperature of the heat collecting piping of FIG. 10, and the amount of heat leaks.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
[A] First embodiment (FIGS. 1 to 3)
FIG. 1 is a pipeline diagram showing a first embodiment of a solar thermal power generation system according to the present invention. FIG. 2 is a cross-sectional view in a direction perpendicular to the axis showing the solar heat collector of FIG.

  A solar thermal power generation system 10 shown in FIG. 1 is a concentrating solar thermal power generation system (CSP), a condensing / heat collecting system 11 including a plurality of solar heat collectors 14, a steam generator 15 as a heat exchanger, and The power generation system 12 includes a superheater 16 and includes a steam turbine 17 (a high pressure steam turbine 17A and a low pressure steam turbine 17B), and a heat storage system 13 including a heat storage heat exchanger 18.

  Although the solar heat collector 14 will be described in detail later, the mirror 20 collects sunlight P, and the heat collection pipe 21 absorbs the collected sunlight P and converts it into heat energy (heat collection). The heat refrigerant R1 flowing inside the heat collecting pipe 21 is heated.

  In the condensing / heat collecting system 11, the plurality of solar heat collectors 14 are arranged in series with the respective heat collecting pipes 21 connected thereto, and the plurality of solar heat collectors 14 arranged in series are arranged in parallel. Arranged in columns. The heat collecting pipes 21 of the plurality of solar heat collectors 14 are connected to a heat refrigerant pipe 23 provided with a circulation pump 22, and the superheater 16 and the steam generator 15 of the power generation system 12 are connected to the heat refrigerant pipe 23. They are arranged sequentially.

  The power generation system 12 includes a steam / condensate pipe 24, and the steam / condensate pipe 24 includes a first circulation pump 25, a steam generator 15, a high-pressure steam turbine 17 </ b> A, a second circulation pump 26, a superheater 16, and a low-pressure steam turbine. 17, the condenser 27 is arrange | positioned one by one. The high-pressure steam turbine 17A and the low-pressure steam turbine 17B have the same turbine shaft, and a generator 28 is connected to the turbine shaft. Reference numeral 29 denotes a cooling tower.

  The steam generator 15 generates steam by exchanging heat with the thermal refrigerant R1 heated by the plurality of solar heat collectors 14 of the light collecting / heat collecting system 11, and guides this steam to the high-pressure steam turbine 17A. The second circulation pump 26 guides the steam that has finished its work in the high-pressure steam turbine 17 </ b> A to the superheater 16, and the superheater 16 exchanges heat with the thermal refrigerant R <b> 1 heated by the solar heat collector 14. Superheated and led to the low pressure steam turbine 17B as superheated steam. The high-pressure steam turbine 17A and the low-pressure steam turbine 17B are rotated by steam and superheated steam, respectively, to drive the generator 28 to generate power. The steam that has finished its work in the low-pressure steam turbine 17 </ b> B is cooled by the condenser 27 to become condensed water, and the first circulation pump 25 supplies this condensed water to the steam generator 15.

  The heat storage system 13 is a system for storing heat energy when excessive heat energy is generated in the solar heat collector 14 of the light collecting / heat collecting system 11. That is, in the steam system 13, the heat storage heat exchanger 18 is connected to the first heat storage pipe 31 having both ends connected to the thermal refrigerant pipe 23. Furthermore, the heat storage heat exchanger 18 is also disposed in the second heat storage pipe 32 to which the low temperature heat storage tank 33 and the high temperature heat storage tank 34 are connected at both ends and the heat storage refrigerant R2 flows.

  When excessive heat energy is generated in the solar heat collector 14 of the light collecting / heat collecting system 11, the heat refrigerant R1 in the heat refrigerant pipe 23 passes through the first heat storage pipe 31 and is used as the heat storage heat exchanger 18. The heat storage refrigerant R2 in the low-temperature heat storage tank 33 flows into the heat storage heat exchanger 18 so that the heat storage refrigerant R2 is heated by heat exchange in the heat storage heat exchanger 18, and the high-temperature heat storage tank. The excess energy is stored in 34.

  When the thermal energy generated in the solar heat collector 14 is insufficient, the heat storage refrigerant R2 in the high-temperature heat storage tank 34 flows to the heat storage heat exchanger 18, and the heat refrigerant R1 in the heat refrigerant pipe 23 stores heat. By flowing into the heat storage heat exchanger 18 via the first heat pipe 31, the heat refrigerant R <b> 1 is heated by heat exchange in the heat storage heat exchanger 18. The heated thermal refrigerant R1 sequentially flows to the superheater 16 and the steam generator 15 of the power generation system 12 to generate steam and rotate the steam turbine 17. At this time, the heat storage refrigerant R <b> 2 cooled by the heat dissipation in the heat storage heat exchanger 18 is stored in the low-temperature heat storage tank 33.

  Incidentally, as shown in FIG. 2, a plurality of solar heat collectors 14 of the light collecting / heat collecting system 11 includes a mirror 20, a heat collecting pipe 21, a glass tube 35 as a light transmitting pipe, and a radiation shield as a heat insulating means. 36, and heats the thermal refrigerant R1 flowing inside the heat collecting pipe 21 by solar heat.

  The mirror 20 is a parabolic trough type mirror having a parabolic cross section, and condenses sunlight P at a focal position. Further, the heat collecting pipe 21 is disposed at the focal position of the mirror 20 so as to face the mirror 20. A light absorbing material (not shown) is applied to the surface of the heat collecting pipe 21. Accordingly, the heat collecting pipe 21 absorbs the sunlight P collected by the mirror 20 and converts it into heat energy (that is, heat collecting), and heats the thermal refrigerant R1 flowing inside.

  The glass tube 35 is comprised with the translucent glass material, and encloses the heat collection piping 21 in a vacuum state. As described above, since the space between the heat collecting pipe 21 and the glass tube 35 is formed in the vacuum space 37 in a vacuum state, heat conduction and convective heat transfer by the gas from the heat collecting pipe 21 to the glass tube 35 is performed. It is suppressed.

  The radiation shield 36 is made of a metal such as aluminum that does not transmit sunlight P, aluminum alloy, copper, copper alloy, and the like, and covers the periphery of the heat collection pipe 21 so that the heat collection pipe reaches a high temperature of 500 ° C., for example. The radiation heat transfer from 21 is reflected, and the heat leakage by this radiation heat transfer is suppressed.

  Specifically, the radiation shield 36 is disposed in a region opposite to the region facing the mirror 20 in the vacuum space 37 between the heat collecting pipe 21 and the glass tube 35, and the heat collecting pipe 21 or glass. It is supported by the pipe 35 (preferably the heat collecting pipe 21). In the entire circumference of the heat collection pipe 21, the area facing the mirror 20 is about 1/3 of the whole circumference of the heat collection pipe 21, but the area opposite to the area facing the mirror 20 is the area of the heat collection pipe 21. It becomes about 2/3 of the entire circumference. Therefore, radiant heat transfer from about 2/3 of the entire circumference of the heat collection pipe 21 is reflected by the radiation shield 36, and the amount of heat leakage due to the radiant heat transfer from the heat collection pipe 21 is suppressed.

In general, the amount of radiant heat transfer Q from a high-temperature object is as follows: ε is the emissivity, σ is the Stefan-Boltzmann constant, _TH is the temperature of the high-temperature object (for example, the heat collecting pipe 21), and _TL is the low-temperature object (for example, a glass tube). The temperature of 35), A can be expressed by the following formula (1), where A is the heat transfer area.

  Here, since the space between the heat collecting pipe 21 and the glass tube 35 is the vacuum space 37, heat conduction and convective heat transfer by the gas from the heat collecting pipe 21 are extremely small. Accordingly, the temperature of the radiation shield 36 is a temperature in which the radiation from the heat collecting pipe 21 to the radiation shield 36 and the radiation from the radiation shield 36 to the glass tube 35 are balanced. For example, when the heat collecting pipe 21 is 500 ° C. and the glass tube 35 is 30 ° C., the radiation shield 36 is 350 ° C. (see the curve diagram Z1 in FIG. 3). As described above, the temperature difference between the heat collecting pipe 21 and the radiation shield 36 is reduced, and the temperature difference between the radiation shield 36 and the glass tube 35 is also reduced. Both the amount of radiant heat transfer to 36 and the amount of radiant heat transfer from the radiation shield 36 to the glass tube 35 are suppressed. As a result, the amount of radiant heat transfer from the heat collecting pipe 21 to the glass tube 35 as a whole is suppressed.

In addition, the emissivity ε between the high temperature object and the low temperature object in the equation (1) is calculated using the emissivity ε _H on the heat transfer surface of the high temperature object and the emissivity ε _L on the heat transfer surface of the low temperature object. Is represented by the following equation (2).

Here, when the high temperature object is the heat collection pipe 21 and the low temperature object is the radiation shield 36, the emissivity ε is the emissivity between the heat collection pipe 21 and the radiation shield 36, and the emissivity ε _H is the heat collection pipe. 21 is the radiation rate at the heat transfer surface, and the radiation rate ε _L is the radiation rate at the heat transfer surface of the radiation shield 36. When the high temperature object is the radiation shield 36 and the low temperature object is the glass tube 35, the emissivity ε is the emissivity between the radiation shield 36 and the glass tube 35, and the emissivity ε _H is transmitted through the radiation shield 36. The emissivity at the hot surface, and ε _L is the emissivity at the heat transfer surface of the glass tube 35.

From the above equation (2), if one of the emissivities ε _H and ε _L is small, the emissivity ε is small. Therefore, the heat collecting pipe 21 and the radiation can be reduced by reducing the emissivities ε _L and ε _H on the heat transfer surface of the radiation shield 36 without processing the surfaces of the heat collecting pipe 21 and the glass tube 35, which have many restrictions. Both the emissivity ε between the shields 36 and the emissivity ε between the radiation shields 36 and the glass tube 36 can be reduced. Thereby, both the amount of radiant heat transfer between the heat collecting pipe 21 and the radiation shield 36 and the amount of radiant heat transfer between the radiation shield 36 and the glass tube 35 can be suppressed.

For this reason, the surface of the radiation shield 36 of the present embodiment is configured as a metal polished surface, and the emissivities ε _L and ε _{H on the} heat transfer surface are set to small values of 0.1 or less. Further, the radiation shield 36 of the present embodiment is provided with an anti-oxidation film on the surface thereof so that the surface is not oxidized and the emissivities ε _L and ε _{H on the} heat transfer surface do not increase. The surface of the radiation shield 36 of the present embodiment is provided with at least one of the above-described metal polished surface and antioxidant film.

  With the configuration as described above, according to the present embodiment, the following effects (1) and (2) are obtained.

  (1) In the solar heat collector 14, since the space between the heat collecting pipe 21 and the glass tube 35 is a vacuum space 37, heat conduction and convective heat transfer by gas from the heat collecting pipe 21 to the glass tube 35 can be suppressed. . Further, in the solar heat collector 14, the radiation shield 36 is disposed in the vacuum space 37 between the heat collection pipe 21 and the glass tube 35, so that radiation heat transfer from the heat collection pipe 21 can be reflected by this radiation shield. The amount of radiant heat transfer can be suppressed. In addition, since the radiation shield 36 is disposed in the vacuum space 37 between the heat collection pipe 21 and the glass tube 35, between the heat collection pipe 21 and the radiation shield 36 and between the radiation shield 36 and the glass tube 35. Each temperature difference becomes small, and the amount of radiant heat transferred from each of the heat collecting pipe 21 and the radiation shield 36 can be suppressed based on the above formula (1).

  As a result of these (suppression of heat conduction by gas and suppression of radiant heat transfer amount), in the solar heat collector 14, the amount of heat leakage from the heat collection pipe 21 is indicated by a heat collection pipe as shown by a curve X1 in FIG. For example, the heat collecting efficiency can be suppressed by increasing the temperature of 21 to 500 ° C., for example. In this way, by using the solar heat collector 14 in which the amount of heat leakage is suppressed in the light collecting / heat collecting system 11, the heat collecting pipe 21 of the solar heat collector 14 is set to a high temperature of, for example, 500 ° C. to collect the solar heat. Even when the heat collection efficiency of the vessel 14 is improved, the solar thermal power generation system 10 with a small amount of heat leakage can be realized. A curve Y1 in FIG. 3 indicates the amount of heat received by the heat collecting pipe 24 after subtracting the amount of heat leakage, and a curve Z1 indicates a change in the temperature of the radiation shield 36.

(2) Since the surface of the radiation shield 36 of the solar heat collector 14 is a polished metal surface and an anti-oxidation film is applied to the surface, the radiation rate on the heat transfer surface of the radiation shield 36 ε _L and ε _H can be reduced. Therefore, the surface of the heat collecting pipe 21 and the glass tube 35 in the solar heat collector 14 is not subjected to processing for reducing the radiation rate, and the like, between the heat collecting pipe 21 and the radiation shield 36, and between the radiation shield 36 and the glass tube 35. The respective emissivities ε in between can be reduced. As a result, the amount of radiant heat transfer between the heat collecting pipe 21 and the radiation shield 36 and between the radiation shield 36 and the glass tube 35 in the solar heat collector 14 can be suppressed based on the formula (1). The amount of heat leakage due to radiation from 21 to the glass tube 35 can be suppressed.

[B] Second Embodiment (FIGS. 4 and 5)
FIG. 4: is sectional drawing of the direction orthogonal to the axis | shaft which shows the solar heat collector in 2nd Embodiment of the solar thermal power generation system which concerns on this invention. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The solar heat collector 41 of the present embodiment is different from the solar heat collector 14 of the first embodiment in that the radiation shield 36 is provided with two layers, thereby causing heat leakage from the heat collecting pipe 21. The amount of heat leakage due to radiation, particularly radiation, is suppressed as compared with the case of one layer.

  As shown in FIG. 5, the ratio of the amount of heat leakage to the amount of heat received by the heat collecting pipe 21 is the curve X2 when the radiation shield 36 is two layers, and the curve Y2 when the radiation shield 36 is one layer. The case of the conventional configuration shown in FIG. 10 in which the radiation shield 36 does not exist is the curve Z2.

  Therefore, according to this embodiment, in addition to the effects (1) and (2) of the first embodiment, the radiation shield 36 has two layers as shown in FIG. The amount of heat leakage from the heat pipe 21 can be further suppressed as compared with the case of the first embodiment.

  In the present embodiment, the case where the radiation shield 36 has two layers has been described. However, the amount of heat leakage from the heat collecting pipe 21 may be further suppressed by providing the radiation shield 36 with three or more layers.

[C] Third embodiment (FIG. 6)
FIG. 6: is sectional drawing of the direction orthogonal to the axis | shaft which shows the solar heat collector in 3rd Embodiment of the solar thermal power generation system which concerns on this invention. In the third embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The solar heat collector 45 of the present embodiment is different from the solar heat collector 14 of the first embodiment in that the region facing the mirror 20 in the vacuum space 37 between the heat collection pipe 21 and the glass tube 35. The heat insulating means arranged in the region opposite to the point is not the radiation shield 36 but the heat insulating material 46.

  The heat insulating material 46 is preferably a ceramic heat insulating material, and is further installed on the outer surface of the heat collecting pipe 21 by bonding or the like. Since the heat insulating material 46 is attached to the outer surface of the heat collecting pipe 21, heat conduction from the heat collecting pipe 21 occurs in the heat insulating material 46, and the temperature of the outer surface of the heat insulating material 46 is the temperature of the heat collecting pipe 21. It becomes lower than the temperature of the outer surface.

  With the configuration as described above, according to the present embodiment, the following effect (3) is obtained.

  (3) In the vacuum space 37 between the heat collecting pipe 21 and the glass tube 35 in the solar heat collector 45, a heat insulating material 46 is disposed in a region opposite to the region facing the mirror 20, and this heat insulation. The material is installed on the outer surface of the heat collecting pipe 21. Therefore, since the outer surface temperature of the heat insulating material 46 becomes lower than the outer surface temperature of the heat collecting pipe 21, the amount of radiant heat transfer from the heat insulating material 46 is based on the above formula (1) when the heat insulating material 46 does not exist. It is suppressed more than the amount of radiant heat transfer. Further, since the inner space of the glass tube 35 is the vacuum space 37, heat conduction and convective heat transfer due to gas from the heat collecting pipe 21 and the heat insulating material 46 can be suppressed.

  As a result, in the solar heat collector 45, the amount of heat leakage from the heat collecting pipe 21 can be suppressed even when the temperature of the heat collecting pipe 21 is increased to, for example, 500 ° C. to improve the heat collecting efficiency. Thus, by using the solar heat collector 45 in which the amount of heat leakage is suppressed in the light collecting / heat collecting system 11, the heat collecting pipe 21 of the solar heat collector 45 is set to a high temperature of, for example, 500 ° C. Even when the heat collection efficiency of the vessel 45 is improved, a solar thermal power generation system with a small amount of heat leakage can be realized.

  In addition, although it is possible to install the heat insulating material 46 on the inner surface of the glass tube 35 in the solar heat collector 45, the amount of radiant heat transfer from the heat collecting pipe 21 to the glass tube 35 depends on the fourth power of the temperature. From (refer to Formula (1)), it is preferable to install the heat insulating material 46 in the heat collecting pipe 21 on the high temperature side from the viewpoint of suppressing the amount of radiant heat transfer.

[D] Fourth embodiment (FIG. 7)
FIG. 7: shows the solar heat collector in 4th Embodiment of the solar thermal power generation system which concerns on this invention, (A) is sectional drawing of the direction in alignment with an axis | shaft, (B) is sectional drawing of the direction orthogonal to an axis | shaft. . In the fourth embodiment, portions similar to those in the first embodiment are denoted by the same reference numerals, and description thereof is simplified or omitted.

  The solar heat collector 51 of the present embodiment is different from the solar heat collector 14 of the first embodiment in that the radiation shield 52 includes a thin metal plate 52A and a frame 52B that supports the thin metal plate 52A. The frame 52B of the radiation shield 52 is supported by the heat collecting pipe 21 using the support material 53, and the support material 53 can slide on the heat collection pipe 21 in the axial direction and the circumferential direction of the heat collection pipe. It is a point attached to.

  Also in the present embodiment, the radiation shield 52 is disposed in a region opposite to the region facing the mirror 20 in the vacuum space 37 between the heat collecting pipe 21 and the glass tube 35. The thin metal plate 52A constituting the radiation shield 52 is made of aluminum, an aluminum alloy, copper, or a copper alloy, and at least one of a metal polished surface and an antioxidant film is applied to the surface.

  With the configuration as described above, the present embodiment has the same effects as the effects (1) and (2) of the first embodiment, and also has the following effects (4) to (6). .

  (4) The temperature of the radiation shield 52 is a temperature in which the radiation from the heat collecting pipe 21 to the radiation shield 52 and the radiation from the radiation sheet 52 to the glass tube 35 are balanced, and the amount of radiant heat transfer becomes the fourth power of the temperature. Therefore, the temperature is close to that of the heat collecting pipe 21. Therefore, since the radiation shield 52 of this embodiment is supported by the heat collecting pipe 21 using the support material 53, the amount of heat conduction through the support material 53 is compared with the case where the glass tube 35 is supported. Can be reduced. As a result, the total heat transfer amount from the heat collecting pipe 21 can be suppressed.

  (5) A support member 53 that supports the radiation shield 52 is attached to the heat collecting pipe 21 so as to be slidable in the axial direction and the circumferential direction of the heat collecting pipe 21. For this reason, even when a difference in thermal expansion occurs between the heat collection pipe 21 and the radiation shield 52 due to a temperature difference, the support material 53 slides with respect to the heat collection pipe 21, so that the support material 53 Thermal stress is not generated, and breakage of the support material 53 can be prevented.

  (6) Since the radiation shield 52 includes the thin metal plate 52A and the frame 52B, the weight can be reduced. For this reason, since the stress which arises in the support material 53 which supports the radiation shield 52 can be reduced, this support material 53 can be reduced in diameter. Therefore, the amount of heat leakage due to heat conduction from the support member 53 can be suppressed.

[E] Fifth embodiment (FIG. 8)
FIG. 8 is a pipeline diagram showing a fifth embodiment of the solar thermal power generation system according to the present invention. In the fifth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is simplified or omitted.

  The solar thermal power generation system 55 of the present embodiment is different from the solar thermal power generation system 10 of the first embodiment in that a plurality of solar thermal collectors constituting the condensing / heat collecting system 11 is a high temperature side solar thermal collector 56A. And the low-temperature side solar collector 56B, and only the high-temperature side solar collector 56A is the solar collector 14 or 41 provided with the radiation shield 36 and the solar collector 46 provided with the heat insulating material 46. It is the point comprised by the solar-heat collector 51 when the container 45 or the radiation shield 52 is provided. The low-temperature side solar heat collector 56B is configured by, for example, a conventional solar heat collector 104 (FIG. 10) that does not include the radiation shield 36, the heat insulating material 46, or the radiation shield 52.

  The radiation shields 36 and 52 and the heat insulating material 46 are highly effective in suppressing the amount of heat leakage, but the cost increases, so it is necessary to be employed according to the degree of the effect. In the low-temperature solar heat collector 56B, the amount of heat leakage from the heat collecting pipe 21 is originally small, so that the effect of suppressing the amount of heat leakage by the radiation shields 36 and 52 and the heat insulating material 46 is small. On the other hand, in the solar collector 56A on the high temperature side, the amount of heat leakage from the heat collecting pipe 21 is large, so the effect of suppressing the amount of heat leakage by the radiation shields 36 and 52 and the heat insulating material 46 is great.

  Therefore, as in the solar thermal power generation system 55 of the present embodiment, the solar heat collector 14 or 41 having the radiation shield 36 only in the high temperature side solar heat collector 56A, the solar heat collector 45 having the heat insulating material 46, or By using the solar heat collector 51 including the radiation shield 52, the effect of suppressing the amount of heat leakage from the heat collecting pipe 21 can be realized at low cost. In addition, also in this embodiment, there exists an effect similar to the effect (1)-(6) of the said 1st-4th embodiment.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this, A component may be variously deformed in the range which does not deviate from the summary, and it covers different embodiment. You may combine a component suitably.

  For example, in each of the above-described embodiments, the solar heat collectors 14, 41, 45, 51, and 104 in the solar power generation systems 10 and 55 are parabolic trough solar heat collectors that use parabolic trough mirrors 20 that have a parabolic cross section. Although the case of a heater has been described, a solar power generation system in which a Fresnel-type solar heat collector using a large number of planar mirrors is adopted as a light collecting / heat collecting system may be used.

10 Solar Thermal Power Generation System 11 Concentration / Heat Collection System 12 Power Generation System 15 Steam Generator (Heat Exchanger)
16 Superheater (heat exchanger)
17 Steam turbine 20 Mirror 21 Heat collection pipe 35 Glass pipe (translucent pipe)
36 Radiation shield (insulation means)
37 Vacuum spaces 41, 45 Solar collector 46 Heat insulation material (heat insulation means)
51 Solar collector 52 Radiation shield (heat insulation means)
52A Metal thin plate 52B Frame 53 Support material 55 Solar power generation system 56A High-temperature side solar collector 56B Low-temperature side solar collector P Sunlight

Claims (11)

A parabolic trough mirror that collects sunlight and has a parabolic cross section ,
A heat collecting pipe that is disposed opposite to the mirror, absorbs sunlight collected by the mirror, collects heat, and heats a heat medium flowing inside,
A solar heat collector having a translucent translucent pipe that insulates and insulates the heat collection pipe in a vacuum state,
In the vacuum space between the heat collecting pipe and the light transmitting pipe , heat insulating means are arranged in all areas opposite to the area facing the mirror, away from the heat collecting pipe and the light transmitting pipe. A solar heat collector characterized by being made. The solar heat collector according to claim 1, wherein the heat insulating means is a radiation shield. The solar heat collector according to claim 2, wherein two or more layers of the radiation shield are provided. The solar heat collector according to claim 2 or 3, wherein a surface of the radiation shield is configured by a metal polished surface. The solar heat collector according to any one of claims 2 to 4, wherein an antioxidant film is provided on a surface of the radiation shield. The solar heat collector according to claim 1, wherein the heat insulating means is a ceramic heat insulating material and is installed on an outer surface of a heat collecting pipe. The solar radiation collector according to claim 2, wherein the radiation shield is supported by a heat collecting pipe using a support material. The solar heat collector according to claim 7, wherein the support material is slidably provided on the heat collection pipe. The solar heat collector according to any one of claims 2 to 5, 7, and 8, wherein the radiation shield includes a thin metal plate and a frame. A light collection / collection system equipped with a solar heat collector that collects sunlight and collects heat to heat the thermal refrigerant;
Power generation comprising a heat exchanger that generates steam by exchanging heat with the thermal refrigerant heated by the solar heat collector, and a steam turbine that rotates by the steam generated by the heat exchanger and drives a generator In a solar thermal power generation system having a system,
10. The solar thermal power generation system according to claim 1, wherein the solar thermal collector is the solar thermal collector according to claim 1. A light collecting / collecting system comprising a plurality of solar heat collectors for collecting sunlight and collecting heat to heat the thermal refrigerant;
Power generation comprising a heat exchanger that generates steam by exchanging heat with the thermal refrigerant heated by the solar heat collector, and a steam turbine that rotates by the steam generated by the heat exchanger and drives a generator In a solar thermal power generation system having a system,
The solar heat collector is divided into a high temperature side solar heat collector and a low temperature side solar heat collector, and the high temperature side solar heat collector is according to any one of claims 1 to 9. A solar thermal power generation system characterized by being a solar thermal collector.

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