Solar heat collecting device

Abstract

The present invention provides a solar heat collecting device having good heat collection efficiency. A uniaxial solar-tracking reflective mirror group is arranged such that each longitudinal axis thereof faces the same direction. A first biaxial solar-tracking reflective mirror group and a second biaxial solar-tracking reflective mirror group are arranged lined up in a direction orthogonal to the longitudinal axis direction of uniaxial solar-tracking reflective mirrors. The uniaxial solar-tracking reflective mirror group is arranged so as to be sandwiched on both sides by the first biaxial solar-tracking reflective mirror group and the second biaxial solar-tracking reflective mirror group. Each mirror group sends solar heat received during uniaxial or biaxial tracking in accordance with the position of the sun, to a heat collecting device.

Claims

1. A solar heat collecting device comprising: a single-axial solar tracking reflection mirror group comprising a plurality of single-axial solar tracking reflection mirrors selected from Fresnel reflection mirrors and trough reflection mirrors; a dual-axial solar tracking reflection mirror group comprising a plurality of dual-axial solar tracking reflection mirrors each having a surface area of 5 to 20% of a surface area of one of the single-axial solar tracking reflection mirrors; a heat collecting unit that collects heat by receiving reflection light from the single-axial solar tracking reflection mirror group and the dual-axial solar tracking reflection mirror group to transfer the heat from a first end to a second end in a length direction of the unit, wherein: the single-axial solar tracking reflection mirror group is disposed so that long axes of the plural single-axial solar tracking reflection mirrors face in a same direction, the dual-axial solar tracking reflection mirror group is divided into a first dual-axial solar tracking reflection mirror group and a second dual-axial solar tracking reflection mirror group, the first and second dual-axial solar tracking reflection mirror groups are disposed side by side in a direction orthogonal to a long-axis direction of the plural single-axial solar tracking reflection mirrors, the single-axial solar tracking reflection mirror group is disposed sandwiched between the first and second dual-axial solar tracking reflection mirror groups, and the heat collecting unit is installed right above the single-axial solar tracking reflection mirror group in the direction of the long axes of plural single-axial tracking type reflection mirrors.

2. The solar heat collecting device according to claim 1, wherein: the dual-axial solar tracking reflection mirror group is divided into the first dual-axial solar tracking reflection mirror group, the second dual-axial solar tracking reflection mirror group, and a third dual-axial solar tracking reflection mirror group; and the third dual-axial solar tracking reflection mirror group is disposed in a direction where long axes of the plural single-axial solar tracking reflection mirrors extend and in a heat transfer direction.

3. The solar heat collecting device according to claim 1, wherein the heat collecting unit is a heat collecting tube, a heat collecting device, or a combination thereof.

4. The solar heat collecting device according to claim 2, wherein the heat collecting unit is a heat collecting tube, a heat collecting device, or a combination thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a power generation system in which a solar heat collecting device according to the present invention is used.

(2) FIG. 2 is a plan view illustrating the arrangement of the reflection mirror groups included in the solar heat collecting device of FIG. 1 (however, the number of mirrors is different from that of FIG. 1).

(3) FIG. 3 is a plan view illustrating the arrangement of reflection mirror groups included in a solar heat collecting device according to an embodiment different from that of FIG. 1.

(4) FIG. 4 is a plan view illustrating the arrangement of reflection mirror groups included in a solar heat collecting device according to an embodiment further different from that of FIG. 1.

(5) FIG. 5 is a plan view illustrating the arrangement of reflection mirror groups included in a solar heat collecting device in which only dual-axial solar tracking type reflection mirror groups are used.

DETAILED DESCRIPTION

(6) (1) Solar Heat Collecting Device of FIGS. 1 and 2

(7) A solar heat collecting device 1 includes a single-axial solar tracking type reflection mirror group 20 and dual-axial solar tracking type reflection mirror groups 30 and 40.

(8) The single-axial solar tracking type reflection mirror group 20 includes the combination of a required number of linear Fresnel type reflection mirrors 21. The linear Fresnel type reflection mirrors 21 are disposed at equal intervals in the width direction with their long axes facing in the same direction (for example, north-south direction).

(9) A dual-axial solar tracking type reflection mirror group is divided into the first dual-axial solar tracking type reflection mirror group 30 and the second dual-axial solar tracking type reflection mirror group 40. The reflection mirror group 30 and the reflection mirror group 40 are disposed side by side in a direction orthogonal to the long-axis direction of the single-axial solar tracking type reflection mirror 21. Here, the single-axial solar tracking type reflection mirror group 20 is disposed sandwiched between the reflection mirror group 30 and the reflection mirror group 40. When the linear Fresnel type reflection mirrors 21 are disposed with their long axes facing in the north-south direction, the first dual-axial solar tracking type reflection mirror group 30 and the second dual-axial solar tracking type reflection mirror group 40 are disposed side by side in the east-west direction.

(10) The first dual-axial solar tracking type reflection mirror group 30 includes the combination of a required number of reflection mirrors 31. The second dual-axial solar tracking type reflection mirror group 40 includes the combination of a required number of reflection mirrors 41. The number of mirrors of the first dual-axial solar tracking type reflection mirror group 30 may be either the same as or different from that of the second dual-axial solar tracking type reflection mirror group 40. The number of mirrors of the first dual-axial solar tracking type reflection mirror group 30 and the second dual-axial solar tracking type reflection mirror group 40 can be adjusted as appropriate in accordance with the intended amount of heat to be collected or the circumstances of the place to install.

(11) Each of the surface area (area of a front surface that receives sunlight) of one reflection mirror 31 and the surface area of one reflection mirror 41 is approximately 10% of the surface area of one linear Fresnel type reflection mirror 21. For example, the reflection mirror 31 with an area of approximately 22 m and the reflection mirror 41 with the same degree of area can be used. The area is not limited to the above as long as the reflection mirror is capable of dual-axial control. FIGS. 1 and 2 illustrate the reflection mirrors 31 and 41 with a square shape. The reflection mirror, however, may have another shape.

(12) In FIG. 1, the combination of a plurality of heat collecting tubes 11 is used as a heat collecting unit 10. Alternatively, a known heat collecting device or a heat collecting unit employing a method of heat, which has been obtained by the heat collecting tube 11, further in another solid (such as concrete molded body) may be used. The heat collecting unit 10 is installed right above the single-axial solar tracking type reflection mirror group 20 in FIGS. 1 and 2. The place to install the heat collecting unit 10 may be changed as appropriate in accordance with the circumstances of the place where the solar heat collecting device 1 is installed. The heat collecting unit 10 is installed by being supported by a supporter made of a metal column, frame, or plate.

(13) Next, a method of operating the solar heat collecting device 1 according to the embodiment of the present invention is described with reference to a power generation system illustrated in FIG. 1. Here, description is made of the embodiment in which water is used as the heat medium flowing through the heat collecting tube 11. Water is sent from a water supply line 71 to the heat collecting tube 11 of the heat collecting unit 10. In the initial stage of the operation, water is supplied from a water source, which is not shown.

(14) The single-axial solar tracking type reflection mirror group 20 reflects the sunlight received while single-axially tracking the position of the sun, and sends the light to the heat collecting unit 10. The first dual-axial solar tracking type reflection mirror group 30 and the second dual-axial solar tracking type reflection mirror group 40 reflect the sunlight received while dual-axially tracking the position of the sun, and send the light to the heat collecting unit 10. The water in the heat collecting unit 10 (heat collecting tube 11) turns into steam. The temperature of the steam can be determined in accordance with the necessary condition. In Japan, the temperature can be increased to be higher than or equal to 600 C. by increasing the light collecting rate.

(15) After that, the steam is supplied to a power generation device 50 having a turbine and a power generator through a steam supply tube 72. The turbine is rotated by the steam supplied to the power generation device 50. The power is generated by transmitting the motive power, which is generated by the rotation of the turbine, to the power generator. The steam used in the rotation of the turbine is sent from a steam return line 73 to a condenser 60. The sent steam is returned to water after the condensation. After that, the generated water is supplied to the heat collecting unit 10 through the water supply line 71. In the time band when the sunlight can be used, the power generation using the solar heat can be continued by repeating the above circulation operation.

(16) (2) Solar Heat Collecting Device of FIG. 3

(17) In a solar heat collecting device of FIG. 3, the position of a dual-axial solar tracking type reflection mirror group 130 is different from that of the solar heat collecting device 1 of FIG. 1. The dual-axial solar tracking type reflection mirror group 130 is disposed in a direction where the long axes of the plural single-axial solar tracking type reflection mirrors 21 extend and in the heat transfer direction. Here, the heat transfer direction refers to the direction where the heat medium (water) of the heat collecting unit 10 (heat collecting tube 11) is transferred, and corresponds to the direction from a first end 10a to a second end 10b in the heat collecting unit 10 in FIG. 3. Since the number of dual-axial solar tracking type reflection mirror groups is smaller in FIG. 3, the shown example contains fewer reflection mirrors. However, the total number of reflection mirrors in the dual-axial solar tracking type reflection mirror group in FIG. 3 can be increased to be equal to the total number of reflection mirrors in the dual-axial solar tracking type reflection mirror group in FIG. 2.

(18) When the water, which is the heat medium, is transferred from the first end (upstream) 10a to the second end (downstream) 10b in the heat collecting unit 10, first, water is heated by the sunlight reflected by the single-axial solar tracking type reflection mirror group 20 in the upstream side. After that, the water is further heated by the sunlight reflected by the dual-axial solar tracking type reflection mirror group 130 in the downstream side. In the solar heat collecting device of FIG. 3, the water as the heat medium is heated in the two stages as above.

(19) (3) Solar Heat Collecting Device of FIG. 4

(20) In the solar heat collecting device of FIG. 4, the reflection mirror groups in the solar heat collecting device of FIGS. 1 and 2 are combined. The single-axial solar tracking type reflection mirror group 20 includes the combination of a required number of linear Fresnel type reflection mirrors 21. The linear Fresnel type reflection mirrors 21 are disposed at equal intervals with their long axes facing in the same direction (for example, north-south direction).

(21) A dual-axial solar tracking type reflection mirror group is divided into the first dual-axial solar tracking type reflection mirror group 30, the second dual-axial solar tracking type reflection mirror group 40, and the third dual-axial solar tracking type reflection mirror group 130. The reflection mirror groups 30 and 40 are disposed side by side in a direction orthogonal to the long-axis direction of the single-axial solar tracking type reflection mirror 21. Here, the single-axial solar tracking type reflection mirror group 20 is disposed sandwiched between the reflection mirror groups 30 and 40. The reflection mirror group 130 is disposed in a direction where the long axes of the plural single-axial solar tracking type reflection mirrors 21 extend, and in the heat transfer direction. Note that in FIG. 4, since the number of dual-axial solar tracking type reflection mirror groups is larger, the shown example contains more reflection mirrors. However, the total number of reflection mirrors in the three dual-axial solar tracking type reflection mirror groups can be decreased to be equal to the total number of reflection mirrors in the dual-axial solar tracking type reflection mirror group in FIG. 2.

(22) The optimum arrangement can be selected from the arrangements of the dual-axial solar tracking type reflection mirror groups illustrated in FIGS. 2 to 4 in consideration of the space and the shape of the place where the solar heat collecting device according to the present invention is installed and how much sunlight the device can receive. On this occasion, the number of reflection mirrors included in one dual-axial solar tracking type reflection mirror group can be increased or decreased as appropriate. Moreover, the solar heat collecting device according to the present invention can be applied to improve the heat collecting efficiency of the existing solar heat collecting device which employs only the single-axial solar tracking type reflection mirror.

(23) (5) Solar Heat Collecting Device of FIG. 5

(24) FIG. 5 illustrates the application example of the solar heat collecting device according to the present invention. In FIG. 5, two dual-axial solar tracking type reflection mirror groups 230 and 330, and two heat collecting units 10 and 110 are provided.

(25) Of the two dual-axial solar tracking type reflection mirror groups, the first dual-axial solar tracking type reflection mirror group 230 is disposed on the upstream side of the heat transfer while the second dual-axial solar tracking type reflection mirror group 330 is disposed on the downstream side of the heat transfer. The first heat collecting unit 10 is disposed right above the first dual-axial solar tracking type reflection mirror group 230, and the second heat collecting unit 110 is disposed right above the second dual-axial solar tracking type reflection mirror group 330. In the operation, the heat medium heated by the first heat collecting unit 10 is further heated by the second heat collecting unit 110. The solar heat collecting device according to the embodiment of the present invention may be any one of the following first to fourth solar heat collecting devices.

(26) The first solar heat collecting device is a solar heat collecting device including a reflection mirror group including a single-axial solar tracking type reflection mirror group and a dual-axial solar tracking type reflection mirror group, and a heat collecting unit for obtaining heat by collecting light from the reflection mirror group. The single-axial solar tracking type reflection mirror group includes a combination of a plurality of reflection mirrors selected from Fresnel type reflection mirrors and trough type reflection mirrors. The dual-axial solar tracking type reflection mirror group includes a combination of a plurality of dual-axial solar tracking type reflection mirrors having a surface area of 5 to 20% of a surface area of one of the single-axial solar tracking type reflection mirrors. The heat collecting unit is a heat collecting tube, a heat collecting device, or a combination thereof for collecting heat by receiving reflection light from the reflection mirror group and transferring the heat from a first end to a second end in a length direction thereof.

(27) In the second solar heat collecting device according to the first solar heat collecting device, the single-axial solar tracking type reflection mirror group is disposed so that long axes of the plural single-axial solar tracking type reflection mirrors face in the same direction. The dual-axial solar tracking type reflection mirror group is divided into a first dual-axial solar tracking type reflection mirror group and a second dual-axial solar tracking type reflection mirror group on opposite sides in a direction orthogonal to a long-axis direction of the plural single-axial solar tracking type reflection mirrors.

(28) In the third solar heat collecting device according to the first solar heat collecting device, the single-axial solar tracking type reflection mirror group is disposed so that long axes of the plural single-axial solar tracking type reflection mirrors extend in the same direction. The dual-axial solar tracking type reflection mirror group is disposed in a direction where the long axes of the plural single-axial solar tracking type reflection mirrors extend and in a heat transfer direction.

(29) In the fourth solar heat collecting device according to the first solar heat collecting device, the single-axial solar tracking type reflection mirror group is disposed so that long axes of the plural single-axial solar tracking type reflection mirrors extend in the same direction. The dual-axial solar tracking type reflection mirror group is divided into a first dual-axial solar tracking type reflection mirror group and a second dual-axial solar tracking type reflection mirror group on opposite sides in a direction orthogonal to a long-axis direction of the plural single-axial solar tracking type reflection mirrors and a third dual-axial solar tracking type reflection mirror group is disposed in a direction where the long axes of the plural single-axial solar tracking type reflection mirrors extend and in a heat transfer direction.

(30) The above descriptions regarding the particular embodiment of the present invention have been presented for the purpose of illustration. They are not intended to be exhaustive or to limit the present invention to the described forms as they stand. It is evident for those skilled in the art that a number of modifications or variations are possible in view of the above-described disclosures.

(31) The solar heat collecting device according to the present invention can be used for the solar thermal power generation. The solar heat collecting device according to the present invention can also be applied to a hot water supply system or a heating system in which steam, hot water, or hot air is used. In the construction of the solar heat collecting device according to the present invention, the local procurement of materials and machinery can be increased. The increase in the local procurement is important to promote the plans for spreading the use of the solar energy.