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SG172326A1 - Solar heat exchanger - Google Patents

Solar heat exchanger Download PDF

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Publication number
SG172326A1
SG172326A1 SG2011045812A SG2011045812A SG172326A1 SG 172326 A1 SG172326 A1 SG 172326A1 SG 2011045812 A SG2011045812 A SG 2011045812A SG 2011045812 A SG2011045812 A SG 2011045812A SG 172326 A1 SG172326 A1 SG 172326A1
Authority
SG
Singapore
Prior art keywords
heat
silicon carbide
light receiving
receiving plate
melting
Prior art date
Application number
SG2011045812A
Inventor
Katsushige Nakamura
Original Assignee
Mitaka Koki Kk
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitaka Koki Kk filed Critical Mitaka Koki Kk
Publication of SG172326A1 publication Critical patent/SG172326A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S10/00Solar heat collectors using working fluids
    • F24S10/70Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S10/00Solar heat collectors using working fluids
    • F24S10/30Solar heat collectors using working fluids with means for exchanging heat between two or more working fluids
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S20/00Solar heat collectors specially adapted for particular uses or environments
    • F24S20/20Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S23/00Arrangements for concentrating solar-rays for solar heat collectors
    • F24S23/70Arrangements for concentrating solar-rays for solar heat collectors with reflectors
    • F24S23/79Arrangements for concentrating solar-rays for solar heat collectors with reflectors with spaced and opposed interacting reflective surfaces
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S60/00Arrangements for storing heat collected by solar heat collectors
    • F24S60/10Arrangements for storing heat collected by solar heat collectors using latent heat
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00Details of absorbing elements
    • F24S70/10Details of absorbing elements characterised by the absorbing material
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24SSOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00Details of absorbing elements
    • F24S70/20Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/40Solar thermal energy, e.g. solar towers
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/40Solar thermal energy, e.g. solar towers
    • Y02E10/44Heat exchange systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Silicon Compounds (AREA)
  • Laminated Bodies (AREA)

Abstract

SOLAR HEAT EXCHANGERA light receiving plate 9 floating on the surface oftin 8, i.e., a low-melting-point heating medium and receiving solar beams L is made of solid carbon material entirely coated with a silicon carbide film 11. Due to the silicon carbide film 11, the surface of the light receivingplate 9 is black to realize a high absorption ratio of the solar beams L. In addition, the light receiving plate 9 is made of the silicon carbide film 11 at least at the surface thereof, to demonstrate excellent heat resistance.Figure 2.

Description

SPECIFICATION
Solar Heat Exchanger
TECHNICAL FIELD
The present invention relates to a solar heat exchanger.
BACKGROUND TECHNOLOGY
There is known a Dbeam-down solar concentration apparatus that reflects, with a plurality of reflection mirrors called heliostats, sclar beams toward a center mirror supported at the top of a high tower and concentrates dewnwardly reflected solar beams from the center mirrcr on a point to obtain heat (for example,
Japanese Unexamined Patent Application Publication No. Hl1l- 118105).
In the case of the beam-down structure of this sort, the downwardly reflected sclar beams directly heat, for example, a metallic coll to change water circulated inside the coil into vapor.
QUTLINE OF INVENTION
According te the structure of the related art of directly heating the metallic coil with solar beams, however, a metallic color of the surface of the metallic coll reflects solar beams to hinder efficient heat exchange.
The surface of the metallic coil is heated with solar beams to very high temperatures, and therefore, a black coating, should it be applied to the surface, will easily peel off.
z
MEANS TO SOLVE THE PROBLEMS
In censideration of the related art, the present invention provides a solar heat exchanger capable of efficiently converting solar beams into heat.
According to a technical aspect of the present invention, a structure includes a top-open, heat-resistant container that helds a low-melting-point heating medium and a light receiving plate that is supported on and is in contact with the surface of the low-melting-point heating medium. It is characterized in that the light receiving plate is made of solid silicon carbide, or solid carbon material entirely coated with a silicon carbide film.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 1s a general view illustrating a solar concentration apparatus according to a first embodiment of the present invention.
Figure 2 is a sectional view illustrating a heat exchanger.
Figure 3 1s a perspective view illustrating a light receiving plate and heat-resistant container.
Figure 4 is an enlarged sectional view illustrating a silicon carbide film on the surface of the light receiving plate and heat-resistant container.
Figure 5 1s a sectional view illustrating a heat exchanger according to a second embodiment of the present invention.
MODE OF IMPLEMENTING INVENTION
First Embodiment
Figures 1 to 4 are views illustrating a first embodiment of the present invention. Numeral 1 represents an elliptic mirror serving as a center mirror that is supported with a suppert tower (not illustrated) at a predetermined height in a downwardly oriented state. A clrecular opening la is formed at the center of the elliptic mirror 1. The elliptic mirror 1 has a mirror surface that 1s defined as a part of an ellipsoid, and under the same, there are a first focus A and a second focus B. Under the elliptic mirror 1, a heat exchanger 2 is arranged to 1¢ cenvert solar beams I inte heat energy. At an upper part of the heat exchanger 2, there is a collector mirror 3 substantially having a tapered cylindrical shape. On the ground around the heat exchanger 2, many heliostats 4 are arranged tc surround the elliptic mirror 1.
Fach of the heliostats 4 1s controlled by a sensor system (not illustrated) so that scolar beams L reflected by the heliostat 4 may pass through the first focus A. Once the solar beams IL reflected by the heliostats 4 pass through the first focus A, the solar beams are downwardly reflected by the elliptic mirror 1, are always collected at the second focus B, and reach the heat exchanger 2 through the collector mirror 3.
The heat exchanger 2 has a box 6 that has an opening 5 at the top thereof and is made of autoclaved lightweight concrete (ALC). The collector mirror 3 is arranged at the opening 5. In the box 6, there 1s a heat-resistant container 7 made of black carbon material. Inside the heat-resistant container 7, there is held tin 8 serving as a low-melting-point heating medium. On the surface of the tin 8, a light receiving plate 9 made of black carbon material floats. In the tin 8, a heat exchanging pipe 10 meanders. In the pipe 10, water W serving as a heat conducting medium is supplied from one side and vapor § is discharged from the other side. “he heat-resistant container 7 has an open top shape having a tapered side face that upwardly widens from a circular bottom. The black carbon material that forms the heat-resistant container 7 is entirely coated with a silicon carbide (SiC) film 11.
The light receiving plate 9 flcoating on the surface of the tin 8 has a disk shape and is made of black carbon material entirely coated with a silicon carbide film 11.
The silicon carbide film 11 itself is black, and therefore, the solar beams L collected by the collector mirror 3 and received by the light receiving plate 9 are absorbed at a high absorption ratic (about 95%) and are changed into heat.
The heat changed by the light receiving plate 9 is conducted te the tin 8 that becomes molten when the temperature thereof reaches a melting point (232°C). The molten tin 8 in a wet state contacts the light receiving plate 9 and pipe 10, to increase heat conduction efficiency to surely convert the water W passing through the pipe 10 into vapor S.
The black carbon material that forms the light receiving plate 9 is smaller in specific gravity than the tin 8, and therefore, the light receiving plate 9 floats on the surface of the tin 8 and never sinks into the tin 8 even 1f the tin 8 becomes molten. The light receiving plate © is entirely coated with the silicon carbide film 11.
The silicon carbide film 11 itself is highly heat resistive and prevents the inside black carbon material from contacting alr, and therefore, the black carbon material never burn even if the light receiving plate 9 is heated to high temperatures.
The heat-resistant container 7 1s also coated with the silicon carbide film 11, and when an exposed part 5 thereof receives solar beams I, the part absorbs the solar beams L and converts the same into heat to heat the tin 8.
In a first stage of the tin 8 receiving heat from the light receiving plate 9, the tin 8 is solid and expands due to the heat. At this time, if the tin 8 and an inner face of the heat-resistant container 7 are tightly attached to each other, stress may concentrate on part of the tin 8 and heat-resistant container 7, to partly distort or break Lhe container.
For this, the embodiment forms the heat-resistant container 7 with black carbon material coated with the silicon carbide film 11. Compared with making the heat- resistant container 7 from metal, contact force between the tin and the container is weaker so that the tin 8 may easily slide on the inner face of the heat-resistant container 7. In addition, the heat-resistant container 7 has an upwardly widening tapered shape to allow the solid tin 8 to slide upwardly. As a result, the tin 8 and heat- resistant container 7 will have no part where stress concentration occurs to cause partial distortion or breakage.
According to the present embodiment, the light receiving plate 9 and heat-resistant container 7 are made of black carbon material coated with the silicon carbide film 11. Instead, they may entirely be made of silicon carbide. Although one piece of the light receiving plate 8 ls floated on the surface of the tin 8, a plurality of small light receiving plates 9 may be floated thereon.
According to the present embodiment, water W passes through the pipe 10 and is converted into vapor S$. Instead, the pipe 10 may pass air as the heat conducting fluid. The air passing through the pipe 10 is heated to high temperatures and is circulated through another apparatus to conduct the heat from the tin 8 to the apparatus.
Instead of the tin 8, low-melting-point metal such as lead and solder may be used as the low-melting-point heating medium. (Second Embodiment)
Figure 5 is a view illustrating a second embodiment of the present invention. This embodiment and embodiments that follow employ structural elements that are similar to those of the first embodiment. Accordingly, similar structural elements are represented with commen marks to omit overlapping explanations.
A heat exchanger 12 according to the present embodiment has a heat-resistant container 13 that is made of stainless steel. A light receiving plate 14 is of an open-top type having a tapered side face that upwardly widens from a circular bottom. Between the light receiving plate 14 and the heat-resistant container 13, there is molten salt 15 serving as a low-melting-point heating medium. The molten salt 15 1s a mixture of potassium nitrate and sodium nitrate and becomes liquid at a melting point of about 140°C. Af an upper end of the heat- resistant container 13, a flange 16 is fixed to press from above the light receiving plate 14 that may rise due to buoyancy. In the molten salt 15, there is a pipe 17.
According to the present embodiment, the light receiving plate 14 has an open top shape to realize a large area to receive solar beams 1... In addition, a contact area thereof to the molten salt 15 is also large. Accordingly, the molten salt 15 can quickly be put in a molten state.
Side faces of the light receiving plate 14 and heat- resistant container 13 are inclined into a tapered shape and the molten salt 15 is heated even around the bottom of the heat-resistant container 13. Due to this, the molten salt 15 in a molten state easily circulates due to convection, to relax temperature variations and further improve heat exchanging efficiency. In addition, the molten salt 15 1s inexpensive compared with, for example, tin, to provide an advantage in terms of cost. The molten salt 15 may be used alone, or may be mixed with solid heat storage material that does not melt when heated.
EFFECT OF INVENTION
According to the present invention, the light receiving plate flcating on the surface of a low-melting- point heating medium and receiving solar beams is made of solid silicon carbide, or solid carbon material entirely coated with a silicon carbide film. Due to the silicon carbide film, the surface of the light receiving plate is black to improve an absorption ratio of solar beams. The light receiving plate is formed with the silicon carbide film at least at the surface thereof, and therefore, demonstrates excellent heat resistance. The low-melting- point heating medium melts to become a liquid heat source that may take any shape depending on the shape of the heat- resistant container. This increases a contact area and improves heat exchange efficiency.
The low-melting-point heating medium may be Jlow- melting-peint metal selected from any one of tin, lead, and solder, to serve as a high-temperature liquid heat source.
The low-melting-point heating medium may be molten salt that is advantageous in terms of cost.
The heat-resistant container has a tapered shape that upwardly widens. Even if the low-melting-point heating medium causes in a solid state a volume change due to thermal expansion during heating or cooling, the low- melting-point heating medium easily slides on the inner face of the heat-resistant contalner, to cause no stress concentration at any part of the low-melting-point heating medium and heat-resistant container. Accordingly, the low- melting-point heating medium and heat-resistant container never cause partial distortion or breakage.
Further, the heat-resistant container is made of solid silicon carbide, or solid carbon material entirely coated with a silicon carbide film, and therefore, even the heat-resistant container can absorb, at its exposed part, solar beams and can change them into heat. Compared with the case of making the heat-resistant container from metal, contact force (a mutual action at an interface) between the solid low-melting-point heating medium and the container is weaker so that the low-melting-point heating medium may easily slide when thermal expansion occurs, thereby reducing stress on the heat-resistant container.
Moreover, the light receiving plate has an open top container shape, to increase a light receiving area and an area in contact with the low-melting-point heating medium, so that the low-melting-point heating medium may quickly be put in a molten state. (United States designation)
In connection with United States designation, this international patent application claims the benefit of priority under Article No. 11%(a) of United States Patent
Law to Japanese Patent Application No. 2008-327647 filed on
December 24, 2008 whose disclosad contents are cited herein.

Claims (6)

  1. CLATMS i. A solar heat exchanger having a structure including a top-open, heat-resistant container holding a low-meiting-point heating medium and a light receiving plate being supported on and in contact with the surface of the low-melting-point heating medium, wherein the light receiving plate is made of solid silicon carbide, or solid carbon material being entirely coated with a silicon carbide film.
  2. Z. The solar heat exchanger according to claim 1, wherein the low-melting-point heating medium is low- melting-point metal selected from any one of tin, lead, and solder.
  3. 3. The solar heat exchanger according to claim 1, wherein the low-melting-point heating medium is molten salt.
  4. 4. The solar heat exchanger according fo any one of claims 1 to 3, wherein the heat-resistant container has an upwardly widening tapered shape.
  5. 5. The solar heat exchanger according to claim 4, wherein the heat-resistant container is made of solid silicon carbide, or solid carbon material being entirely coated with a silicon carbide film.
  6. 6. The solar heat exchanger according to any one of claims 1 te 5, wherein the light receiving plate has an open top container shape.
SG2011045812A 2008-12-24 2009-12-24 Solar heat exchanger SG172326A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008327647 2008-12-24
PCT/JP2009/071427 WO2010074141A1 (en) 2008-12-24 2009-12-24 Solar ray heat conversion device

Publications (1)

Publication Number Publication Date
SG172326A1 true SG172326A1 (en) 2011-07-28

Family

ID=42287748

Family Applications (1)

Application Number Title Priority Date Filing Date
SG2011045812A SG172326A1 (en) 2008-12-24 2009-12-24 Solar heat exchanger

Country Status (6)

Country Link
US (1) US20110253128A1 (en)
JP (1) JP5156842B2 (en)
CN (1) CN102257331A (en)
AU (1) AU2009331219B2 (en)
SG (1) SG172326A1 (en)
WO (1) WO2010074141A1 (en)

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JP5337612B2 (en) 2009-07-27 2013-11-06 三鷹光器株式会社 Heat exchange structure for solar heat converter
US9291371B1 (en) * 2010-09-27 2016-03-22 Gary M. Lauder Light-admitting heliostat
US9909730B2 (en) * 2010-09-27 2018-03-06 Gary M. Lauder Processor-controlled light-admitting heliostat
CN102607187B (en) * 2011-01-24 2014-11-05 三鹰光器株式会社 Heat exchange structure for solar ray heat conversion device
ES2417079B1 (en) * 2011-08-01 2014-09-22 Carlos GALDÓN CABRERA SOLAR RADIATION RECEIVER
WO2013100780A1 (en) * 2011-12-29 2013-07-04 Квантрилл Эстейт Инк Apparatus for concentrating energy
ITRM20120135A1 (en) * 2012-04-03 2013-10-04 Magaldi Ind Srl HIGH-LEVEL ENERGY DEVICE, PLANT AND METHOD OF ENERGY EFFICIENCY FOR THE COLLECTION AND USE OF THERMAL ENERGY OF SOLAR ORIGIN.
JP2013245877A (en) * 2012-05-25 2013-12-09 Soken Technics Kk Solar heat medium heating device
JP6217976B2 (en) * 2014-02-26 2017-10-25 独立行政法人国立高等専門学校機構 Haze processing apparatus and haze processing method
JP2017151214A (en) * 2016-02-23 2017-08-31 株式会社ジャパンディスプレイ Display device
AU2018210678A1 (en) * 2017-01-19 2019-08-22 The University Of Adelaide Concentrated solar receiver and reactor systems comprising heat transfer fluid
FR3149673A1 (en) * 2023-06-12 2024-12-13 Heliosand SOLAR LAVA HEAT EXCHANGER

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Also Published As

Publication number Publication date
JPWO2010074141A1 (en) 2012-06-21
US20110253128A1 (en) 2011-10-20
AU2009331219B2 (en) 2013-08-29
AU2009331219A1 (en) 2011-07-21
CN102257331A (en) 2011-11-23
JP5156842B2 (en) 2013-03-06
WO2010074141A1 (en) 2010-07-01

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