Heat exchanging structure of solar heat exchanger

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US 2011/011.4082 A1 May 19, 2011

HEAT EXCHANGING STRUCTURE OF 0013. In FIG.1, a secondary mirror 1 is an elliptical mirror SOLAR HEAT EXCHANGER and is installed at a predetermined height on a tower (not illustrated). The elliptical mirror 1 is downwardly oriented. A

BACKGROUND OF THE INVENTION mirror surface of the elliptical mirror 1 is part of a spheroid. 0001 1. Field of the Invention Below the spheroid in a long axis direction, a first focus A and 0002 The present invention relates to a heat exchanging a second focus B that are confocal are present. Arranged structure of a Solar heat exchanger. under the elliptical mirror 1 is a solar heat exchanger 3 that 0003 2. Description of Related Art converts Solar rays L into thermal energy. The Solar heat 0004. A solar concentration apparatus used with a solar exchanger 3 is accommodated in a housing 5 that has a top heat exchanger is disclosed in, for example, Japanese UneX opening 4 and is made of ALC (autoclaved lightweight con amined Patent Application Publication No. H11-119105. crete). The opening 4 of the housing 5 is provided with a This related art is a beam-down solar concentration apparatus collector mirror 6 having a tapered cylindrical shape. An inner that employs primary mirrors called heliostats. The heliostats face of the housing 5 may be coated with a reflective film to reflect outward thermal radiation.

reflect solar rays toward a secondary mirror installed at the 0014. On the ground around the solar heat exchanger 3, top of a tower. The secondary mirror downwardly reflects the many heliostats 7 serving as primary mirrors are arranged to Solar rays so that the reflected Solar rays are concentrated at a surround the elliptical mirror 1. Each of the heliostats 7 is point on the ground.

0005 According to this related art, the downwardly controlled by a solar ray sensor (not illustrated) so that a solar reflected Solar rays strike a light receiving plate on the ground, beamL reflected by the heliostat 7 may pass through the first to heat the light receiving plate to 1000 degrees centigrade or focus A. The solar beams L reflected by the heliostats 7 and higher. passed through the first focus A are downwardly reflected by the elliptical mirror 1, are collected at the second focus B, are

SUMMARY OF THE INVENTION gathered by the collector mirror 6, and are received by the Solar heat exchanger 3.

0006. The related art mentioned above directly heats the 0015 Inside the housing 5, a heat-resistant container 8 of light receiving plate with Solar rays to very high temperatures. heat-resistant metal is arranged with a space interposed If the high-temperature heat is effectively extracted through between the housing 5 and the container 8. The container 8 heat exchange from the light receiving plate, the heat will has an open top and a tapered side wall that widens from a efficiently be used. In practice, however, the light receiving circular bottom toward the open top. plate becomes too hot to make it directly contact with a heat 0016. The heat-resistant container 8 holds tin 9 that is a exchanging fluid Such as water or oil and there has been low-melting-point metal. The tin9 has a melting point of 232 proposed no heat exchanging structure that is useful for the C. and melts as is heated with Solar beam. A light receiving high-temperature heat receiving plate. plate 10 floats on the tin9. The light receiving plate 10 is made 0007. The present invention provides a heat exchanging of a black carbon material and is covered with a silicon structure of a Solar heat exchanger, capable of safely extract carbide (SiC) film. The light receiving plate 10 is shaped into ing heat from a high-temperature light receiving plate. a container having an open top, similar to the container 8. 0008 According to an aspect of the present invention, the According to the present embodiment, the container 8, tin 9. Solar heat exchanger includes a heat-resistant container hav and light receiving plate 10 constitute the solar heat ing an open top and containing a low-melting-point metal and exchanger 3.

a light receiving plate of carbon material floating on the 0017. Around the heat-resistant container 8, a heat low-melting-point metal so that the light receiving plate is exchanging pipe 11 is arranged in a spiral shape. The pipe 11 irradiated with Solar rays from above. The heat exchanging is arranged not to touch the container 8. Namely, a clearance structure includes a housing of heat insulating material con is secured between the pipe 11 and the container 8. figured to accommodate the Solar heat exchanger and a pipe 0018. Another pipe 12 in a spiral shape is arranged above configured to pass a heat exchanging fluid. The pipe is the Solar heat exchanger 3. The pipe 12 is arranged in Such a arranged in a space between the housing and the Solar heat way as not to interfere with the solar beams L radiated from exchanger in Such a way as not to touch the Solar heat the collector mirror 6. The upper pipe 12 is connected to the exchanger. lower pipe 11 through a flexible pipe (not illustrated). The lower pipe 11 is vertically movable relative to the heat-resis

BRIEF DESCRIPTION OF THE DRAWINGS tant container 8. The vertical movement of the lower pipe 11 0009 FIG. 1 is a general view illustrating a solar heat results in changing the clearance between the lower pipe 11 exchanger and a heat exchanging structure according to an and the container 8.

embodiment of the present invention; 0019. The pipe 11 passes oil H serving as a heat exchang 0010 FIG. 2 is a sectional view illustrating the solar heat ing fluid and/or a heat carrier. The oil H has a heatproof exchanger and heat exchanging structure; and temperature of about 400°C. If the temperature exceeds 400° 0011 FIG. 3 is a perspective view illustrating a light C., the oil H changes its properties. When the temperature is receiving plate of the Solar heat exchanger. lower than 400°C., as the oil His heated the heat can be taken outside.

DESCRIPTION OF THE PREFERRED 0020 Operation of the solar heat exchanger 3 according to EMBODIMENT the present embodiment will be explained. Solar beams L hit the light receiving plate 10, which converts the solar beams L 0012. A heat exchanging structure of a solar heat into heat. The light receiving plate 10 has a container-like exchanger according to an embodiment of the present inven shape with an open top, and therefore, has a large light receiv tion will be explained in detail with reference to FIGS. 1 to 3. ing area compared with a flat plate, to effectively heat itself.

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US 2011/011.4082 A1 May 19, 2011

The light receiving plate 10 is made of a carbon material and therefore, has a large light receiving area to heat itself to coated with a silicon carbide film, and therefore, has a good higher temperatures compared with a flat light receiving light absorbing characteristic and heat resistant characteris plate.

tic. The heat of the light receiving plate 10 is transferred to the 0027. According to the present invention, the pipe is ver tin 9, which becomes molten when the temperature thereof tically movable relative to the solar heat exchanger 3, to adjust reaches the melting point thereof. a clearance between the pipe and the Solar heat exchanger 3 0021. The moltentin9 is present between the light receiv and optimize the quantity of radiant heat acting on the pipe. ing plate 10 and the heat-resistant container 8 and is in contact 0028. According to the present invention, the light receiv with both of them, to effectively transfer heat from the light ing plate 10 is made of solid silicon carbide or a solid carbon receiving plate 10 to the container 8. Namely, the solar heat material coated with a silicon carbide film, to realize a high exchanger 3 including the light receiving plate 10, tin 9, and Solar beam absorbing efficiency and heat resistance. 0029. Although the invention has been described above by container 8 is not only aheat source of very high temperature reference to certain embodiments of the invention, the inven but also a radiator to radiate heat around the same. tion is not limited to the embodiments described above. 0022. The radiant heat from the container 8 is a main heat Modifications and variations of the embodiments described Source for the oil H passing through the pipe 11 and heats the above will occur to those skilled in the art, in light of the oil H through the pipes 11 and 12. Since the oil H is heated teachings. The scope of the invention is defined with refer with the radiant heat, the temperature of the oil H does not ence to the following claims.

excessively increase, and therefore, the properties of the oil H What is claimed is:

never deteriorate. 1. A heat exchanging structure of a Solar heat exchanger, 0023 The lower pipe 11, which is in the vicinity of the the Solar heat exchanger including a heat-resistant container Solar heat exchanger 3 and has a high heating efficiency due to having an open top and containing a low-melting-point metal the radiant heat, is vertically movable to adjust the clearance and a light receiving plate of carbon material floating on the between the pipe 11 and the heat-resistant container 8. This low-melting-point metal so that the light receiving plate is results in adjusting the quantity of radiant heat applied to the irradiated with Solar rays from above, the heat exchanging pipe 11 and optimizing the temperature of oil H passing structure comprising:

through the pipe 11. a housing of heat insulating material configured to accom 0024. According to the present embodiment, the light modate the Solar heat exchanger, and a pipe configured to pass a heat carrier, the pipe being receiving plate 10 is made of a black carbon material coated arranged in a space between the housing and the solar with a silicon carbide film. Instead, the light receiving plate heat exchanger and not in contact with the Solar heat 10 may entirely be made of silicon carbide. According to the exchanger.

embodiment, the low-melting-point metal is tin. Instead, the 2. The heat exchanging structure of claim 1, wherein low-melting-point metal may be lead or solder. the light receiving plate has a container-like shape having 0025. As mentioned above, the present invention makes an open top.

the pipe for passing a heat carrier not to touch the Solar heat 3. The heat exchanging structure of claim 1, wherein exchanger 3 including the light receiving plate 10, so that the the pipe is configured to be movable vertically relative to heat carrier in the pipe is heated with radiant heat from the the Solar heat exchanger.

Solar heat exchanger 3. This configuration secures safety. The 4. The heat exchanging structure of claim 1, wherein temperature of the Solar heat exchanger 3 becomes very high, the light receiving plate is made of solid silicon carbide or and therefore, the radiant heat therefrom can surely heat the a solid carbon material entirely coated with a silicon heat carrier in the pipe. carbide film.

0026. According to the present invention, the light receiv ing plate 10 has a container-like shape having an open top,