JP2014163305A - Parallel structure of stirling engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parallel structure of a plurality of stirling engines for simultaneously driving the stirling engines.SOLUTION: Heating parts 17 of a plurality of stirling engines 16 are arranged to be exposed within a heated air passage 14 through which heated air H flows. Therefore, the heated air H flows as fluid to the downstream stirling engine 16 to securely heat the downstream stirling engine 16, which allows the plurality of stirling engines 16 to be driven simultaneously.

Description

  The present invention relates to a side-by-side structure of Stirling engines.

  A Stirling engine operates a piston by a temperature difference caused by heating an internal working fluid by a heating unit or cooling by a cooling unit, and drives a generator by a reciprocating motion of the piston.

  There is also a proposal using solar heat as a heat source for driving the Stirling engine. The sunlight condensed by a Fresnel lens or the like is guided to the heating part of the Stirling engine by an optical fiber or the like, and the heating part is heated by directing sunlight to the heated air (for example, see Patent Document 1). .

JP-A-2005-344608

  However, in such a conventional technique, it is difficult to drive a plurality of Stirling engines at the same time because of the structure in which the collected sunlight is directly applied to the heating unit of the Stirling engine. That is, in order to drive a plurality of Stirling engines at the same time, it is necessary to divide and apply the concentrated sunlight to the heating portions of the respective Stirling engines, which complicates the optical structure. In the structure in which the heating unit of the Stirling engine is exposed in one large optical path, the heating unit of the downstream Stirling engine is behind the upstream and the juxtaposition is not established.

  The present invention has been made paying attention to such a problem of the conventional technology, and an object thereof is to provide a side-by-side structure capable of simultaneously driving a plurality of Stirling engines.

  The invention according to claim 1 is a heat receiving part into which sunlight reflected by the heliostat enters, a heating air passage through which heated air that has passed through the heat receiving part is sent, and a heating part facing the heating air path, respectively. It is characterized by comprising a plurality of Stirling engines installed in a heated state.

  The invention according to claim 2 is characterized in that the heated air passing through the heated air passage is circulated to the heat receiving portion.

  According to a third aspect of the present invention, there are provided a center mirror installed at a position higher than the ground and having a reflective surface on the lower surface, and a plurality of reflectors installed in a ground area around the center mirror and reflecting sunlight toward the center mirror. The heliostat has a structure in which the sunlight reflected by the heliostat is reflected downward by the center mirror and collected at the ground position, and the heat receiving part is installed at the sunlight collecting position at the ground position. It is characterized by being.

  According to a fourth aspect of the present invention, the center mirror has a curved surface whose cross section matches a spheroid, and has a first focal point and a second focal point below, and has a lower opening than the upper opening. A cylindrical condenser mirror having a smaller surface and a mirror inner surface is installed in a state where the center of the upper opening and the second focal point are substantially coincided with each other, and the heat receiving portion is a lower opening of the cylindrical condenser mirror. The heliostat is installed in the vicinity, and the heliostat is controlled so that reflected light is directed toward the first focal point.

  According to the first aspect of the present invention, since the heating unit of the plurality of Stirling engines faces the heated air passage through which the heated air flows, the heated air flows into the downstream Stirling engine as a fluid. It can be heated and a plurality of Stirling engines can be driven simultaneously.

  According to the second aspect of the present invention, since the heated air passing through the heated air path is repeatedly circulated to the heat receiving portion, there is little heat loss and the solar heat utilization efficiency is increased.

  According to the third aspect of the present invention, the Stirling engine can be easily installed because the condensing device is a beam-down type and the heat receiving portion is located on the ground.

  According to the fourth aspect of the present invention, if the center mirror has a curved surface whose cross section matches an ellipse, and the sunlight reflected by the heliostat passes through the first focus of the center mirror, Light is always collected geometrically at the second focal point. Therefore, the heliostat has only to be controlled so that the reflected light always goes to the first focal point, and the heliostat can be easily controlled. In addition, since the cylindrical condenser mirror is positioned around the second focal point, sunlight deviating from the second focal point can be taken into the cylindrical condenser mirror and reliably guided to the heat receiving part while being reflected by the inner surface. .

A side view showing a beam down type solar condensing device used in an embodiment. The top view which shows a beam down type solar condensing device. The figure which shows the parallel arrangement structure of a Stirling engine. Sectional drawing which shows the cylindrical condensing mirror and the internal structure of a heat receiving part. The top view which shows a cylindrical collector mirror. The top view which shows a heat receiving part. The perspective view which shows a heat receiving part.

  Preferred embodiments of the present invention will be described with reference to the drawings.

  First, a beam-down solar concentrator for obtaining solar heat will be described. In this embodiment, a case of an area in the middle latitude of the northern hemisphere such as Japan will be described as an example.

  A center mirror 1 is supported by three towers (not shown) at the center of the beam-down solar concentrator. The center mirror 1 has a partial spheroid shape in which the opposite side to the direction in which the sun exists during the day is cut out. As shown in FIG. 1, the center mirror 1 has a curved surface whose section matches an ellipse, and a first focal point A and a second focal point B exist as confocal points below.

  As shown in FIG. 2, the center mirror 1 is in a state of projecting by a predetermined angle range to the east side and the west side from the semicircle in a plan view. A plurality of heliostats 2 are installed on the north side and the east and west sides of the center mirror 1.

  The heliostat 2 has a structure that changes its direction in conjunction with the movement of the sun by a sensor (not shown), and is always controlled to reflect the sunlight L toward the first focus A. The sunlight L that has passed through the first focal point A is reflected by the center mirror 1 and collected at the second focal point B.

  A cylindrical condenser mirror 3 is installed at the second focal point B. The cylindrical condenser mirror 3 has a generally tapered cylindrical shape in which the lower opening is narrower than the upper opening, and the inner surface is a mirror surface constituted by a plurality of multi-mirror segments. All the reflected light of the heliostat 2 is reflected by the center mirror 1 and then introduced into the cylindrical condenser mirror 3. A heat receiving portion 4 is provided below the cylindrical condenser mirror 3.

  The cylindrical condenser mirror 3 is covered with a rectangular housing 5, and a hollow portion 6 exists between the cylindrical condenser mirror 3 and the housing 5. An air inlet 7 to the hollow portion 6 is formed in the upper portion of the housing 5.

  The heat receiving portion 4 on the lower side of the cylindrical condenser mirror 3 is accommodated in a housing 8. The heat receiving portion 4 is provided so as to close the cross section of the housing 8.

  The housing 5 of the cylindrical condenser mirror 3 and the housing 8 of the heat receiving unit 4 are connected via an air passage 12. A transparent window 13 is formed on the upper surface of the housing 8 facing the lower opening of the cylindrical collector mirror 3. The transparent window 13 is made of quartz glass having heat resistance.

  The heat receiving part 4 is composed of a plurality of heat exchanging members 9, each having a black and multi-hole structure made of a silicon carbide film (SiC) as a nonmetallic heat resistant material and having a heat resistance of about 1000 ° C. or more. ing. Each heat exchange member 9 is housed in a funnel-shaped cover 15 (FIG. 7) for uniformizing the passing air.

  A loop-shaped heated air passage 14 is formed from the housing 8 below the heat receiving portion 4, and air is circulated in a certain direction by a blower (not shown) inside.

  A plurality of Stirling engine 16 heating portions 17 are arranged in parallel in the heated air passage 14 along the heated air passage 14. The Stirling engine 16 encloses a working fluid such as hydrogen or helium in a sealed container, and moves the piston 19 by alternately moving the working fluid between the heating unit 17 and the cooling unit 18. The piston 19 can drive the generator 20 to generate electricity. The heating unit 17 of the Stirling engine 16 is provided at one end, and the heating unit 17 is installed in a state of facing the heating air passage 14.

  Therefore, the housing 8 and the plurality of Stirling engines 16 are arranged in series on the heating air passage 14 forming the circulation air passage, and in the housing 8 as a heat source, a heat load is transferred from the low temperature side (C) to the high temperature side (H). In each Stirling engine 16, air passes from the high temperature side to the low temperature side. Moreover, you may switch to the air path which bypasses the heating part 17 of the Stirling engine 16 as needed. The total energy efficiency can be increased by selecting 16 Stirling engines that operate depending on the heat receiving situation.

  Next, a process of heating air with sunlight in the heat receiving unit 4 will be described.

  First, all the sunlight L reflected by the center mirror 1 is introduced into the cylindrical collector mirror 3 and is reflected and collected by the inner surface thereof, but the cylindrical collector mirror 3 itself is heated during reflection. Therefore, the cylindrical condenser mirror 3 becomes very hot. Therefore, the air taken in from the air intake 7 is preliminarily heated in contact with the back surface of the cylindrical condenser mirror 3 in the hollow portion 6.

  The air heated to some extent is introduced into the upper space 10 of the heat exchange member 9 through the air passage 12. The air introduced into the upper space 10 passes through the heat receiving part 4 and reaches the lower space 11. At this time, since the heat receiving unit 4 is irradiated with high-energy sunlight L from the lower opening of the cylindrical condenser mirror 3 through the transparent window 13 and the heat receiving unit 4 itself is very hot, the air receives heat. Heated air H is produced in the process of passing through the part 4.

  Since this heated air H circulates in the heated air path 14, the heating unit 17 of each Stirling engine 16 is heated by the heated air H, and a plurality of Stirling engines 16 can be driven simultaneously.

  In addition, the air C whose temperature has decreased after passing through the heated air passage 14 is repeatedly circulated to the heat receiving unit 4. Therefore, there is little heat loss and the utilization efficiency of solar heat increases.

  Furthermore, since the condensing device is a beam-down type and the heat receiving part 4 is at the ground position, the Stirling engine 16 can be easily installed.

  In addition, the center mirror 1 has a curved surface with a cross section that matches an ellipse. If the sunlight L reflected by the heliostat 2 passes through the first focal point A of the center mirror 1, the sunlight L Always converges to the second focal point B geometrically. Therefore, the heliostat 2 may be controlled so that the reflected light always travels toward the first focal point A, and the heliostat 2 can be easily controlled. Further, since the cylindrical condenser mirror 3 is located around the second focal point B, the sunlight L that is out of the second focal point B is also taken into the cylindrical condenser mirror 3 and reflected on the inner surface to ensure the heat receiving portion. 4 can be led.

  Although the example which condenses sunlight with respect to the heat exchange member 9 with the beam down type solar condensing device was shown in the above embodiment, it is not limited to it, What kind of condensing device may be sufficient.

2 Heliostat 4 Heat receiving part 14 Heating air path 16 Stirling engine 17 Heating part H Heating air A 1st focus B 2nd focus L Sunlight

Claims (4)

A heat receiving part (4) into which sunlight reflected by the heliostat enters,
A heated air passage (14) through which heated air that has passed through the heat receiving section is sent;
A Stirling engine side-by-side structure comprising a plurality of Stirling engines (16) installed in a state in which the heating section faces each of the heating air passages.   The parallel structure of Stirling engines according to claim 1, wherein the heated air passage forms a circulating air passage including a heat receiving portion and a plurality of Stirling engines, and the heated air is circulated to the heat receiving portion. A center mirror installed at a position higher than the ground and having a reflecting surface on the lower surface, and a plurality of heliostats installed in a ground area around the center mirror and reflecting sunlight toward the center mirror, The sunlight reflected by the heliostat is reflected downward by the center mirror and focused on the ground.
3. The Stirling engine side-by-side structure according to claim 1, wherein the heat receiving portion is installed at a sunlight collecting position on the ground position. The center mirror has a curved surface whose cross section matches a spheroid, and has a first focus and a second focus below.
A cylindrical condenser mirror in which the lower opening is smaller than the upper opening and the inner surface is a mirror surface is installed in a state in which the center of the upper opening and the second focal point are substantially matched,
The heat receiving part is installed near the lower opening of the cylindrical condenser mirror,
4. The Stirling engine side-by-side structure according to claim 3, wherein the heliostat is controlled so that reflected light is directed toward the first focal point.

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