JP2015094534A - Trough solar thermal collector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trough solar thermal collector capable of effectively using total direct solar radiation incident on a reflector and excellent in heat collection efficiency.SOLUTION: A trough solar thermal collector collecting sunlight reflected by a trough reflector in a heat collecting tube, includes a drive unit (such as rotary gears and chains) provided on a back surface of the reflector or in a lower portion of the reflector for driving the reflector to rotate so as to track sunlight.

Description

  The present invention relates to a trough solar collector that collects solar heat energy by concentrating sunlight on a heat collecting tube.

  The use of renewable energy is being promoted to help prevent global warming associated with fossil fuel consumption and stabilize the energy supply on a global scale. Renewable energies include solar energy, wind power, wave power, and geothermal heat. Moreover, as solar energy, there are cases where it is used in the form of solar heat and a system that directly uses sunlight.

  In the case of using solar heat, a trough-type solar heat collector that is condensed on a heat collecting tube by a trough-type reflector and heats a fluid in the heat collecting tube to be used as a heat medium is known. For example, there is a technique disclosed in Patent Document 1. Specifically, a technology is disclosed in which a heat collecting tube is arranged on the rotation axis of a parabolic reflector, sunlight reflected by the reflecting mirror is collected on the heat collecting tube, and the fluid in the heat collecting tube is heated. Yes. Conventional trough solar collectors use a configuration in which a reflector and a heat collecting tube are integrated by a frame.

US2008 / 0078380A1

  Conventionally, many of the reflectors of trough solar collectors have a rotating axis in the north-south direction, and the reflecting mirror rotates around the rotating axis from east to west according to the movement of the sun during the day. It is configured to track in a state where the reflector is always facing the sunlight. In other words, the solar light tracking function sequentially collects sunlight by collecting light on the heat collecting tube.

  In general, a mirror frame that is a strength member, a chain disk for rotating the reflecting mirror, or the like is provided at both ends of the reflecting mirror as a member that forms a parabolic curved surface of the trough reflecting mirror. Since these members cause a shadow on the reflecting mirror when sunlight enters the reflecting mirror, the incident light incident on the heat collecting tube is smaller than the projected area of the reflecting mirror. Therefore, the heat collection efficiency through sunlight tracking in a day is about 5 to 20% lower than the projected area of the reflector.

  That is, in the prior art, for example, a structure in which frames are provided at both ends of a reflector on one side, and a heat collecting tube is penetrated or fixed to those frames, the shadow of the frame is reflected on the reflector depending on solar altitude and sunshine hours. There is a problem that the entire surface of the reflection mirror cannot be used effectively.

  An object of the present invention is to provide a trough solar collector that can effectively use the total amount of direct solar radiation incident on a reflecting mirror and is excellent in heat collection efficiency (= heat amount obtained by heating medium / incident heat amount of sunlight) Is to provide.

  The trough solar collector according to the present invention is characterized in that a drive unit for rotating the reflecting mirror to track the reflecting mirror to sunlight is provided on the back surface of the reflecting mirror or below the reflecting mirror.

  According to the present invention, when the sunlight incident on the reflecting mirror is linearly collected on the heat collecting tube, the sunlight blocking member interposed between the reflecting mirror and the heat collecting tube is basically removed. It becomes possible to provide a trough solar collector with improved heat collection efficiency.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a front view of the trough type solar heat collector of the example of the present invention (example 1). 1 is a side view of a trough solar collector according to an embodiment of the present invention (Example 1). FIG. It is a front view of the trough type solar heat collector of other examples of the present invention (example 2). It is a front view of the trough type solar heat collector of other examples of the present invention (example 3). It is a partial front view of the trough type solar heat collector of other examples of the present invention (example 4).

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  First, the background to the present invention will be described. The present inventors tried a heat collection experiment by solar light tracking using a trough type solar heat collector. As a result, the following knowledge was obtained as a member that causes a shadow on the reflecting mirror.

1) Since the reflected light from the reflecting mirror is collected on the heat collecting tube, a structure in which the heat collecting tube itself always casts a shadow on the central axis of the reflecting mirror is unavoidable.
2) The support extended from the reflector that supports the heat collection tube also casts a shadow on the reflector.
3) The mirror frames for forming a parabolic curved surface at both ends of the reflector also cast shadows on the reflector.
4) The disc-shaped rotating gear of the rotating shaft provided to move the chain that rotates the reflecting mirror also casts a shadow on the reflecting mirror. In particular, when the heat collecting tube is used as the rotating shaft, the ratio of the shadow of the disk-shaped rotating gear using the heat collecting tube as the rotating shaft is large.

  Based on the above knowledge, in a trough solar collector with a heat collection tube as the rotation axis, a structure that enables automatic solar tracking without using a connecting member between the heat collection tube and the reflector as much as possible We found that it is desirable to configure as follows.

  That is, the heat collecting tube is supported by a support column having a diameter equal to or smaller than the outer diameter of the heat collecting tube, and usually the mirror frame provided between the heat collecting tube and the reflecting mirror is deleted, and a disk-shaped rotating gear is installed below the reflecting mirror. It is to be configured.

  The trough-type solar heat collector that removes the sunlight blocking member (the member that casts a shadow on the reflecting mirror) that was interposed between the reflecting mirror and the heat collecting tube, and maximizes the amount of sunlight incident on the reflecting mirror. It is possible to provide a vessel structure.

  Note that the trough solar collector according to the present invention is such that the curved surface of the mirror that reflects sunlight has a parabolic shape, and parallel light incident on the reflector (referred to as direct solar radiation) is collected in the heat collecting tube. It refers to a heat collector that has a structure that shines and whose rotation axis of the reflecting mirror coincides with the central axis of the heat collecting tube. Therefore, in the trough solar collector, the reflector that tracks sunlight sequentially tracks the sunlight in the solar radiation direction with the heat collection tube as the rotation axis.

  The basic components of the trough-type solar collector are a heat collecting tube for circulating a heat medium and a support member for the heat collecting tube, a parabolic reflector for reflecting the sunlight to the heat collecting tube and collecting the line. A rotating gear and a motor that drive the reflecting mirror by tracking the sunlight. In the present invention, when the sunlight is linearly collected on the heat collecting tube, the solar tracking of the reflecting mirror is made possible while eliminating the member that casts a shadow on the reflecting mirror as much as possible.

A first embodiment of the present invention will be specifically described with reference to FIG.
FIG. 1 is a front view of a trough solar collector that collects direct sunlight 13 on a heat collecting tube 1 and heats a heat medium in the heat collecting tube 1. FIG. 1 shows an AA arrow view in FIG.
In FIG. 1, the trough solar collector of the present embodiment includes a heat collecting tube 1 for circulating a heat medium, a reflecting mirror 2 for reflecting direct solar radiation 13, a reflecting shell 3 for reinforcing the reflecting mirror 2, and a reflecting mirror. 2 and the reflector outer shell 3, the connecting plate 4, the support column 5 supporting the heat collecting tube 1, the base 6 located at the bottom of the support column 5, the motor drive shaft 7 provided on the support column 5, the reflection It comprises a rotating gear 8 for driving the mirror shell 3 to follow the sun at an angle of sunlight, and a chain 12 for transmitting a rotational force from the motor drive shaft 7 to the rotating gear 8. The motor drive shaft 7 is provided with a chain wheel 7a that meshes with the chain 12.

FIG. 2 is a side view of the trough solar collector shown in FIG. FIG. 2 is a view seen from the longitudinal direction of the reflector outer shell 3. In FIG. 2, only one reflecting mirror 2 is shown. However, the motor 15 for rotating the motor drive shaft 7 may be in a ratio of one unit to a plurality of reflecting mirrors 2, and as shown in FIG. There is no need to provide a motor 15 for every two.
The motor 15 is connected to the motor drive shaft 7, the chain wheel 7 a provided on both sides of the motor drive shaft 7, and the chain wheel 10 a provided on the gear drive shafts 10 and 11 (the chain wheel provided on the drive shaft 11). And the rotation of the motor 15 is transmitted to the gear drive shafts 10 and 11 via the chain 12. Further, on both sides of the gear drive shafts 10 and 11, a total of four rotary gears 8 are installed, two on each side. The four rotary gears 8 are provided so as to be fitted into the rotary gear groove 14 provided on the front surface (back surface) of the reflector outer shell 3. The heat collecting tube 1 is supported by support columns 5 provided in the vicinity of both ends of the reflecting mirror 2, and the support columns 5 are held by a base base 6. The column 5 is provided with the motor drive shaft 7 and the gear rotation shafts 10 and 11 described above (the column 5 is provided with a frame for supporting the rotation shafts 10 and 11 but not shown).

  Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described.

  In the present embodiment, the direct sunlight 13 from the sun is reflected by the reflecting mirror 2 and condensed on the heat collecting tube 1 to heat the heat medium in the heat collecting tube 1. In this case, the cross-sectional shape of the reflecting mirror 2 has a parabolic shape called a parabolic trough type (commonly referred to as a trough type) so that direct sunlight 13 which is parallel light is linearly focused on the surface of the heat collecting tube 1. ing. However, since the solar altitude changes from moment to moment, the trough-type reflector 2 also requires a so-called tracking operation that changes the angle in the incident direction of sunlight in order to match the direction of the sun. This is achieved by rotating every minute.

  In this embodiment, in order to rotate the reflecting mirror 2 having a parabolic curved surface, a semicircular reflecting mirror outer shell 3 is combined with the reflecting mirror 2 using the connecting plate 4, and the reflecting mirror outer shell 3 is rotated. The reflecting mirror 2 can be rotated about the heat collecting tube 1 as a rotation axis. If a rotating gear 8 or the like for rotating the reflecting mirror 2 is provided between the heat collecting tube 1 and the reflecting mirror 2, the rotating gear 8 or the like casts a shadow on the reflecting mirror 2 to reduce the heat collecting efficiency. Installed on the back side or the lower side of the outer shell 3. In addition, as shown in FIG. 2, two rotating gears 8 are placed on both sides of the reflector outer shell 3 in the longitudinal direction, and a total of four rotating gears 8 are fitted into the rotating gear grooves 14 provided in the reflector outer shell 3. Thus, the position of the reflecting mirror 2 is maintained. When tracking the reflecting mirror 2 in the direction of sunlight, the motor driving shaft 7 is rotated by the motor 15 and the gear driving shafts 10 and 11 connected by the chain 12 are rotated in a desired direction. 3 and the reflecting mirror 2 rotate around the heat collecting tube 1, and the direct sunlight 13 is always focused on the heat collecting tube 1 to heat the heat medium in the heat collecting tube 1.

  In the present embodiment, since a connection member is not used between the heat collecting tube 1 and the reflecting mirror 2, a component that becomes a shadow of the direct sunlight 13 that enters the reflecting mirror 2 and reflects to the heat collecting tube 1 is used. The heat collection efficiency (= the amount of heat obtained by the heating medium / the amount of incident heat of sunlight) can be improved. Moreover, since the reflecting mirror shell 3 is combined with the four rotating gears 8, heat can be collected in a stable posture.

Next, Embodiment 2 of the present invention will be described with reference to FIG. The description will focus on the differences from the first embodiment.
FIG. 3 is a front view of a trough solar collector that collects the direct sunlight 13 on the heat collecting tube 1 and heats the heat medium in the heat collecting tube 1. In FIG. 3, the trough solar collector of the present embodiment is configured to transmit the rotational force directly from the motor drive shaft 7 to the rotary gear 8. Also in the second embodiment, the rotating gear groove 14 is provided on the back surface of the reflector outer shell 3, and the rotating gear 8 is engaged with the rotating gear groove 14.

  With respect to one reflecting mirror 2, two rotating gears 8 are placed on both sides in the longitudinal direction of the reflecting mirror 2, for a total of two to control the rotation of the reflecting mirror 2. As described above, in the second embodiment, since there are two rotating gears 8 in contact with one reflector outer shell 3, the posture of the reflector 2 is difficult to stabilize. For this reason, in Example 2, a tension belt 16 is connected to both sides in the longitudinal direction of the reflector shell 3, and tension is applied from both sides of the reflector shell 3 by penetrating the tension belt 16 into the base base 6. Thus, the posture of the reflecting mirror 2 is stably maintained.

Next, the operation of the embodiment of FIG. 3 will be described. The basic operation is the same as in the first embodiment.
In this embodiment, the rotary gear 8 to which the rotational force is directly transmitted from the motor drive shaft 7 is installed so as to mesh with the rotary gear groove 14 provided on the back surface of the reflector outer shell 3. When tracking the parabolic curved reflecting mirror 2 in the direction of sunlight, the motor drive shaft 7 is rotated to directly rotate the rotary gear 8. While the reflecting mirror 2 is rotating, a constant tension is always applied between the reflecting mirror outer shell 3 and the base base 6 by the tension belt 16 to suppress the influence of disturbance such as wind pressure. As a result, the reflector outer shell 3 and the reflector 2 rotate around the heat collecting tube 1, and the direct sunlight 13 is always collected on the heat collecting tube 1, and the heat medium in the heat collecting tube 1 is heated.

  Also in this embodiment, since the connection member is not used between the heat collecting tube 1 and the reflecting mirror 2, it is a non-contact configuration, so that the component that becomes the shadow of the direct sunlight 13 that enters the reflecting mirror 2 and reflects to the heat collecting tube 1 The heat collection efficiency (= the amount of heat obtained by the heating medium / the amount of incident heat of sunlight) can be improved. Further, since two rotating gears 8 are required per one reflecting mirror 2, and the tension belt 16 is used instead of the chain 12, the cost can be reduced.

Next, Embodiment 3 of the present invention will be described with reference to FIG. The description will focus on the differences from the first and second embodiments.
FIG. 4 is a front view of a trough solar collector that collects the direct sunlight 13 on the heat collecting tube 1 and heats the heat medium in the heat collecting tube 1. In FIG. 4, the trough solar collector of the present embodiment is configured to transmit the rotational force directly from the motor drive shaft 7 to the rotary gear 8, as in the second embodiment. In the third embodiment, the support 5 is provided with the slide support portion 17 so as to be in contact with the back surface of the reflector outer shell 3. Since the support columns 5 are provided on both sides, two slide support portions 17 are installed on one reflector outer shell 3.

  With respect to one reflecting mirror 2, two rotating gears 8 are placed on both sides in the longitudinal direction of the reflecting mirror 2, for a total of two to control the rotation of the reflecting mirror 2. In addition, in order to stabilize the posture of the reflector 2, the chain 18 is connected to both longitudinal sides of the reflector outer shell 3, and the posture of the reflector 2 is maintained by rotating the rotating gear 8 meshed with the chain 18. doing. The connection between the chain 18 and the reflector outer shell 3 is made through a connecting portion 19.

Next, the operation of the embodiment of FIG. 4 will be described. The basic operation is the same as in the first and second embodiments.
In this embodiment, when tracking the parabolic curved reflecting mirror 2 in the direction of sunlight, the rotating shaft 8 is rotated directly by rotating the motor drive shaft 7, and the reflecting mirror 2 is rotated via the chain 18. Rotate in desired direction. The reflector outer shell 3 is controlled to a desired rotation angle while sliding on the slide support portion 17. Since the reflector outer shell 3 and the rotary gear 8 are always connected by the chain 18, the influence of disturbance such as wind pressure can be suppressed. As a result, the reflector outer shell 3 and the reflector 2 rotate around the heat collecting tube 1, and the direct sunlight 13 is always collected on the heat collecting tube 1, and the heat medium in the heat collecting tube 1 is heated.

  Also in this embodiment, since the connection member is not used between the heat collecting tube 1 and the reflecting mirror 2, it is a non-contact configuration, so that the component that becomes the shadow of the direct sunlight 13 that enters the reflecting mirror 2 and reflects to the heat collecting tube 1 The heat collection efficiency (= the amount of heat obtained by the heating medium / the amount of incident heat of sunlight) can be improved. Further, two slide support portions 17 are provided on one reflector outer shell 3 to determine the position of the reflector 2, and the rotary gear 8 and the reflector outer shell 3 are directly connected by the chain 18, so that the reflector mirror The angle control accuracy of 2 can be improved.

Next, Embodiment 4 of the present invention will be described with reference to FIG. The description will focus on the differences from the first to third embodiments.
FIG. 5 is a front view of a trough solar collector that condenses direct sunlight 13 on the heat collecting tube 1 and heats the heat medium in the heat collecting tube 1. In FIG. 5, the trough solar collector of the present embodiment is configured to transmit the rotational force directly from the motor drive shaft 7 to the rotary gear 8, as in the second and third embodiments. In the fourth embodiment, a roller 20 is provided on the column 5 so as to be in contact with the back surface of the reflector outer shell 3. Since the columns 5 are provided on both sides, the rollers 20 are installed in two places on one reflector outer shell 3.

  With respect to one reflecting mirror 2, two rotating gears 8 are placed on both sides in the longitudinal direction of the reflecting mirror 2, for a total of two to control the rotation of the reflecting mirror 2. In order to stabilize the posture of the reflecting mirror 2, a chain 18 is connected to an intermediate point on both sides of the back surface in the longitudinal direction of the reflecting mirror outer shell 3 via the connecting portion 19, and the rotating gear 8 meshed with the chain 18 is connected. The posture of the reflecting mirror 2 is maintained by rotating it.

Next, the operation of the embodiment of FIG. 5 will be described. The basic operation is the same as in the first to third embodiments.
In this embodiment, when tracking the parabolic curved reflecting mirror 2 in the direction of sunlight, the rotating shaft 8 is rotated directly by rotating the motor drive shaft 7, and the reflecting mirror 2 is rotated via the chain 18. Rotate in desired direction. The reflector outer shell 3 is controlled to a desired rotation angle while rolling on the roller 20. In order to stabilize the posture of the reflector outer shell 3, a plurality of rollers 20 are installed side by side (for example, a plurality of rollers 20 are installed on the support column 5 by providing a frame (not shown) extending in the lateral direction). May be. Since the reflector outer shell 3 and the rotary gear 8 are always connected by the chain 18, the influence of disturbance such as wind pressure can be suppressed. As a result, the reflector outer shell 3 and the reflector 2 rotate around the heat collecting tube 1, and the direct sunlight 13 is always collected on the heat collecting tube 1, and the heat medium in the heat collecting tube 1 is heated.

  Also in this embodiment, since the connection member is not used between the heat collecting tube 1 and the reflecting mirror 2, it is a non-contact configuration, so that the component that becomes the shadow of the direct sunlight 13 that enters the reflecting mirror 2 and reflects to the heat collecting tube 1 The heat collection efficiency (= the amount of heat obtained by the heating medium / the amount of incident heat of sunlight) can be improved. Further, since the chain 18 is provided at an intermediate point on the back surface of one reflector outer shell 3, the rotary gear 8 can be reduced in size.

  The trough solar collector of the present invention can be used not only as a heat source for an air conditioner or a refrigerator, but also as a heat source for a plant factory or a snowmelt heat source in winter depending on the temperature level of the heat collection medium.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 Heat collecting tube 2 Reflecting mirror 3 Reflecting mirror outer shell 4 Connection board 5 Support | pillar 6 Base stand 7 Motor drive shaft 8, 9 Rotating gear 10, 11 Gear driving shaft 12, 18 Chain 13 Direct sunlight 14 Rotating gear groove 15 Motor 16 Tension belt 17 Slide support part 19 Connection part 20 Roller

Claims (10)

A trough solar collector that collects sunlight reflected by a trough reflector into a heat collecting tube,
A trough solar collector that includes a driving unit that rotates the reflecting mirror to track the reflecting mirror to sunlight on a back surface of the reflecting mirror or on a lower portion of the reflecting mirror. The trough solar collector according to claim 1,
The shape of the outer surface of the reflecting mirror that forms the back surface of the reflecting mirror is formed in a semicircular arc shape,
The drive unit is composed of a rotating gear,
A trough solar collector, wherein a rotating gear groove that meshes with the rotating gear is formed on the back surface of the reflecting mirror formed in a semicircular arc shape. The trough solar collector according to claim 2,
The said drive part is comprised so that the said rotation gear may be driven via a chain by the drive shaft provided under the said rotation gear, The trough type solar heat collector characterized by the above-mentioned. In the trough type solar collector according to claim 3,
The trough-type solar collector is characterized in that four rotating gears are provided per one reflecting mirror. The trough solar collector according to claim 2,
The trough solar collector, wherein the drive unit includes a drive shaft that supports and rotates the rotating gear. The trough solar collector according to claim 5,
Two rotating gears are provided per one reflecting mirror,
A tension belt connected to both sides of the reflector in the longitudinal direction;
The trough-type solar heat collector, wherein the tension belt is provided so as to penetrate a base base of the trough-type solar heat collector. The trough solar collector according to claim 1,
A slide support that contacts the back of the reflector and supports the rotation of the reflector;
The trough solar collector, wherein the driving unit is provided below the reflecting mirror and below the slide support unit. The trough solar collector according to claim 7,
The trough solar collector according to claim 1, wherein the drive unit includes a rotary gear that is rotationally driven and a chain that is driven by the rotary gear and that is connected to both sides of the reflector in the longitudinal direction. The trough solar collector according to claim 1,
A roller that contacts the back of the reflector and supports the rotation of the reflector;
The trough solar collector, wherein the driving unit is provided below the reflecting mirror and below the roller. The trough solar collector according to claim 9,
The trough solar collector, comprising: a rotary gear that is rotationally driven; and a chain that is driven by the rotary gear and that is connected to both left and right sides of the reflector in the longitudinal direction.

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