Patent Application
20170205117
This disclosure is directed to a thermal insulation composite for a solar tower of an thermal energy generation system.
Concentrated solar power systems generate electrical power by collecting solar thermal energy from the sun with mirrors or lenses and concentrating the solar thermal energy onto a solar energy receiver that sits atop a solar tower. The solar energy receiver is generally a boiler containing water. The concentrated solar thermal energy converts the liquid water in the boiler into steam. The generated stream is transferred to an electrical power generator, such as a steam-powered turbine to produce electricity.
The solar tower must be sufficiently thermally insulated from the solar energy concentrated onto the tower by the mirrors or lenses in order to protect the structural integrity of the solar tower and the overall solar thermal energy generation system. To this end, it is known to attach thermal insulation panels made from refractory ceramic fiber to portions of the tower in the area where the solar thermal energy is concentrated in order to shield or otherwise insulate the tower.
The thermal insulation panels attached to the solar thermal towers experience severe thermal cycling and weathering during normal use. In a typical 24 hour period, it is not uncommon for the thermal insulation panels to experience temperatures as hot as 700 to 900° C. during daytime peak sunlight hours to temperatures of 0° C. and below during the night. This extreme temperature range makes it difficult to design thermal insulation systems that are able to withstand the extreme temperatures, thermal expansion, and thermal cycling of the system.
What is needed in the art is a thermal insulation system for the solar thermal energy tower and energy generation system that is able to withstand large fluctuations in temperatures experienced by the solar tower.
Provided is a thermal insulation composite for a solar tower comprising a support layer, at least one thermal insulation layer adjacent to said support layer, and a thermally expandable layer adjacent said at least one thermal insulation layer.
According to certain illustrative embodiments, provided is a thermal insulation composite for a solar tower comprising a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
According to certain illustrative embodiments, the thermal insulation composite comprises, in order, a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
Also provided is a solar tower comprising a thermal insulation composite attached to the tower, said composite comprising at least one support layer, at least one thermal insulation layer adjacent to said support layer, and a thermally expandable layer adjacent said at least one thermal insulation layer.
According to certain illustrative embodiments, the solar tower comprising a tower and at least one thermal insulation composite attached to the tower, said thermal insulation composite comprising a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
According to certain illustrative embodiments, said solar tower comprises a tower and at least one thermal insulation system attached to the tower, said thermal insulation composite comprising, in order, a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
Further provided is a solar thermal power generation system comprising at least one heliostat, a tower, a solar energy receiver positioned near the top of said tower, and at least one thermal insulation composite comprising a support layer, at least one thermal insulation layer adjacent to said support layer, and a thermally expandable layer adjacent said at least one thermal insulation layer.
According to certain illustrative embodiments, the solar thermal power generation system comprising at least one heliostat, a tower, a solar energy receiver positioned near the top of said tower, and at least one thermal insulation composite attached to the tower, said thermal insulation composite comprising a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
According to certain illustrative embodiments, said solar thermal power generation system comprises at least one heliostat, a tower, a solar energy receiver positioned near the top of said tower, and at least one thermal insulation system attached to the tower, the thermal insulation composite comprising, in order, a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
The thermal insulation composite for a solar tower and concentrated solar thermal energy generation system comprises a multiple layer composite assembly. The thermal insulation composite for a solar tower comprises a support layer, at least one thermal insulation layer adjacent to said support layer, and a thermally expandable layer adjacent said at least one thermal insulation layer. According to certain illustrative embodiments, The thermal insulation composite for a solar tower comprises a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member.
According to certain illustrative embodiments, the thermal insulation composite comprises, in order, a support layer, a thermal insulation paper layer, a thermal insulation board layer, a thermally expandable gasket layer, and a retaining member. According to other illustrative embodiments, there can be other interposed or interleaved layers between one or more of the thermal insulation paper layer and the thermal insulation board layer, or between the thermal insulation board layer and the thermally expandable gasket layer, or between the thermally expandable gasket layer and the retaining member. For example, and without limitation, thermal insulation blankets and/or metal foil layers may be interposed between the support, paper, board, and/or gasket layers.
Each of the thermal insulation paper layer, thermal insulation board layer, and thermally expandable gasket layer may independently be comprised of several sub-layers that collectively comprise the layer.
For example, and only by way of illustration, the thermal insulation paper layer may be comprised of one thermal insulation paper or may be comprised of more than one thermal insulation paper that collectively comprise the thermal insulation paper layer. According to certain illustrative embodiments, the thermal insulation paper layer is comprised of a single thermal insulation paper of a desired thickness and geometry.
For example, and only by way of illustration, the thermal insulation board layer may be comprised of one thermal insulation board or may be comprised of more than one thermal insulation board that collectively comprise the thermal insulation board layer. According to certain illustrative embodiments, the thermal insulation board layer is comprised of a single thermal insulation board of a desired thickness and geometry.
For example, and only by way of illustration, the thermally expandable gasket layer may be comprised of one the thermally expandable gasket or may be comprised of more than one the thermally expandable gasket that collectively comprise the thermally expandable gasket layer. According to certain illustrative embodiments, the thermally expandable gasket layer is comprised of a single the thermally expandable gasket of a desired thickness and geometry.
According to certain illustrative embodiments, thermal insulation comprises a base or support layer having a least one opening to cooperate with or engage a fastener. A thermal insulation paper layer is disposed or otherwise positioned adjacent to the support layer. A thermal insulation board is disposed or otherwise positioned adjacent to the thermal insulation paper layer. A thermally expandable gasket layer is disposed or otherwise positioned adjacent to the thermal insulation board layer. A retaining member is positioned adjacent to the thermally expandable gasket layer. At least one elongated fastener is passed or threaded through the support, paper, board, and gasket layers and the retaining member to affix or otherwise fasten the thermal insulation composite to a solar tower to be thermally insulated, with the support layer adjacent the tower member being thermally insulated.
The thermal insulation composite is incorporated into a solar tower. The solar tower comprises a base and an upwardly extending tower. The tower includes a solar energy receiver positioned at or near the top of the solar tower, and at least one of the presently-disclosed thermal insulation composites attached to a portion of the tower. The thermal insulation composite may be attached or connected at or near the top of the upwardly extending solar tower.
The solar thermal power generation system includes at least one heliostat that is adapted to and is capable of collecting solar energy from the sun and concentrating the solar energy on the solar energy receiver. The solar thermal power generation system also includes an upwardly extending tower having a solar energy receiver positioned at or near the top of the tower that is positioned to receive solar energy from one or more of the heliostats of the energy generation system. According to certain illustrative embodiments, there is a plurality of heliostats that are positioned in an array in a solar energy collection field at least partially surrounding the base or lower end of the solar tower. The heliostats are configured with an angle to capture or collect solar energy from the sun and to concentrate the collected solar energy on the solar receiver that is positioned on the solar energy tower. According to certain embodiments, the heliostats comprise a plurality of mirrors. According to certain embodiments, the heliostats comprise a plurality of lenses.
According to certain illustrative embodiments, the solar energy receiver that is positioned at or near the top of the solar energy tower comprises a water boiler. The water boiler is in fluid communication with a steam-powered turbine. The solar energy collected by the heliostats and concentrated on the water-boiler heats the water contained in the water-boiler to produce steam. The produced steam is transferred to a steam-powered turbine to produce electricity.
The support layer of the thermal insulation composite comprises a base or support plate. The support plate may be a substantially planar plate. Without limitation, and only by way of illustration, the support plate of the thermal insulation composite comprises a metal, a metal alloy, or a composite material. According to certain embodiments, the support plate comprises a metal alloy plate. According to further embodiments, the support plate comprises a steel plate having opposite facing first and second major surfaces. According to further embodiments, the support plate comprising a steel plate includes opposite facing first and second major surfaces, and one or more apertures or openings for accepting a fastener for affixing or fastening the thermal insulation assembly to a solar energy tower. The first major surface faces toward the solar tower and the second major surface faces away from the solar tower. The support layer possesses a sufficient rigidity to support the thermal insulation board to minimize or prevent wind-driven cracking of the board.
The thermal insulation paper layer comprises opposite facing first and second major surfaces. The first major surface of the thermal insulation paper layer is positioned adjacent to the second major surface of the support layer. The thermal insulation paper may be prepared from thermally insulating fibrous materials and optionally a binder for the fibers.
The thermal insulation board layer comprises opposite facing first and second major surfaces. The first major surface of the thermal insulation board layer is positioned adjacent to the second major surface of the thermal insulation paper. The thermal insulation board may be prepared from thermally insulating fibrous materials. Without limitation, a suitable thermal insulation board is commercially available from Unifrax I LLC (Tonawanda, N.Y., USA) under the designation FIBERFRAX® METEOBOARD®.
The thermally expanding gasket layer comprises opposite facing first and second major surfaces. The first major surface of the thermally insulating gasket layer is positioned adjacent to the second major surface of the thermal insulation board layer. The thermally expandable gasket may be prepared from thermally insulating fibrous materials, a thermally expandable material, and optionally a binder. Without limitation, a suitable thermally expanding gasket material is commercially available from Unifrax I LLC (Tonawanda, N.Y., USA) under the registered trademark ISOMAX®.
Any heat resistant inorganic fibers may be utilized in the thermal insulation paper or thermal insulation board so long as the fibers can withstand the paper and board forming process, and can withstand the temperature extremes experienced during normal operation of the solar tower and energy generation system. Without limitation, suitable inorganic fibers that may be used include high alumina polycrystalline fibers, refractory ceramic fibers such as alumino-silicate fibers, alumina-magnesia-silica fibers, kaolin fibers, alkaline earth silicate fibers such as calcia-magnesia-silica fibers and magnesia-silica fibers, S-glass fibers, S2-glass fibers, E-glass fibers, quartz fibers, silica fibers and combinations thereof.
According to certain illustrative embodiments, the heat resistant inorganic fibers comprise ceramic fibers. Without limitation, suitable ceramic fibers include alumina fibers, alumina-silica fibers, alumina-silica-magnesia fibers, alumina-zirconia-silica fibers, zirconia-silica fibers, zirconia fibers and similar fibers. A useful alumina-silica ceramic fiber is commercially available from Unifrax I LLC (Tonawanda, N.Y., USA) under the registered trademark FIBERFRAX®. The FIBERFRAX® ceramic fibers comprise the fiberization product of about 45 to about 75 weight percent alumina and about 25 to about 55 weight percent silica. The FIBERFRAX® fibers exhibit operating temperatures of up to about 1540° C. and a melting point up to about 1870° C.
The alumina/silica fiber may comprise from about 40 weight percent to about 60 weight percent Al2O3 and about 60 weight percent to about 40 weight percent SiO2. The fiber may comprise about 50 weight percent Al2O3 and about 50 weight percent SiO2. The alumina/silica/magnesia glass fiber typically comprises from about 64 weight percent to about 66 weight percent SiO2, from about 24 weight percent to about 25 weight percent Al2O3, and from about 9 weight percent to about 10 weight percent MgO. The E-glass fiber typically comprises from about 52 weight percent to about 56 weight percent SiO2, from about 16 weight percent to about 25 weight percent CaO, from about 12 weight percent to about 16 weight percent Al2O3, from about 5 weight percent to about 10 weight percent B2O3, up to about 5 weight percent MgO, up to about 2 weight percent of sodium oxide and potassium oxide and trace amounts of iron oxide and fluorides, with a typical composition of 55 weight percent SiO2, 15 weigh percent Al2O3, 7 weight percent B2O3, 3 weight percent MgO, 19 weight percent CaO and traces of the above mentioned materials.
Without limitation, suitable examples of biosoluble alkaline earth silicate fibers that can be used include those fibers disclosed in U.S. Pat. Nos. 6,953,757, 6,030,910, 6,025,288, 5,874,375, 5,585,312, 5,332,699, 5,714,421, 7,259,118, 7,153,796, 6,861,381, 5,955,389, 5,928,075, 5,821,183, and 5,811,360, all of which are incorporated herein by reference.
According to certain embodiments, the biosoluble alkaline earth silicate fibers may comprise the fiberization product of a mixture of oxides of magnesium and silica. These fibers are commonly referred to as magnesium-silicate fibers. The magnesium-silicate fibers generally comprise the fiberization product of about 60 to about 90 weight percent silica, from greater than 0 to about 35 weight percent magnesia and 5 weight percent or less impurities. According to certain embodiments, the alkaline earth silicate fibers comprise the fiberization product of about 65 to about 86 weight percent silica, about 14 to about 35 weight percent magnesia and 5 weight percent or less impurities. According to other embodiments, the alkaline earth silicate fibers comprise the fiberization product of about 70 to about 86 weight percent silica, about 14 to about 30 weight percent magnesia, and 5 weight percent or less impurities. A suitable magnesium-silicate fiber is commercially available from Unifrax I LLC (Tonawanda, N.Y., USA) under the registered trademark ISOFRAX®. Commercially available ISOFRAX® fibers generally comprise the fiberization product of about 70 to about 80 weight percent silica, about 18 to about 27 weight percent magnesia and 4 weight percent or less impurities.
According to certain embodiments, the biosoluble alkaline earth silicate fibers may comprise the fiberization product of a mixture of oxides of calcium, magnesium and silica. These fibers are commonly referred to as calcia-magnesia-silica fibers. According to certain embodiments, the calcia-magnesia-silicate fibers comprise the fiberization product of about 45 to about 90 weight percent silica, from greater than 0 to about 45 weight percent calcia, from greater than 0 to about 35 weight percent magnesia, and 10 weight percent or less impurities. Useful calcia-magnesia-silicate fibers are commercially available from Unifrax I LLC (Tonawanda, N.Y. USA) under the registered trademark INSULFRAX®. INSULFRAX® fibers generally comprise the fiberization product of about 61 to about 67 weight percent silica, from about 27 to about 33 weight percent calcia, and from about 2 to about 7 weight percent magnesia. Other suitable calcia-magnesia-silicate fibers are commercially available from Thermal Ceramics (Augusta, Ga., USA) under the trade designations SUPERWOOL 607, SUPERWOOL 607 MAX and SUPERWOOL HT. SUPERWOOL 607 fibers comprise about 60 to about 70 weight percent silica, from about 25 to about 35 weight percent calcia, and from about 4 to about 7 weight percent magnesia, and trace amounts of alumina. SUPERWOOL 607 MAX fibers comprise about 60 to about 70 weight percent silica, from about 16 to about 22 weight percent calcia, and from about 12 to about 19 weight percent magnesia, and trace amounts of alumina. SUPERWOOL HT fiber comprise about 74 weight percent silica, about 24 weight percent calcia and trace amounts of magnesia, alumina and iron oxide.
The expanding material of the thermally expanding gasket material may be selected from unexpanded vermiculite, expandable graphite, hydrobiotite, water-swelling tetrasilicic flourine mica, alkaline metal silicates, or mixtures thereof. According to certain embodiments, the expanding material is unexpanded vermiculite.
The thermal insulation paper and board, and thermally expanding gasket, may include one or more inorganic binder(s), one or more organic binder(s), or a combination of one or more inorganic binder(s) and one or more organic binder(s).
Without limitation, suitable inorganic binders may include colloidal dispersions of alumina, silica, zirconia, and mixtures thereof. The organic binder(s) may be provided as a solid, a liquid, a solution, a dispersion, a latex, or similar form. Examples of suitable organic binders include, but are not limited to, acrylic latex, (meth)acrylic latex, phenolic resins, copolymers of styrene and butadiene, vinylpyridine, acrylonitrile, copolymers of acrylonitrile and styrene, vinyl chloride, polyurethane, copolymers of vinyl acetate and ethylene, polyamides, organic silicones, organofunctional silanes, unsaturated polyesters, epoxy resins, polyvinyl esters (such as polyvinylacetate or polyvinylbutyrate latexes) and the like.
According to certain embodiments, the thermally expandable gasket layer comprises inorganic, low bio-persistent (ie., biosoluble) fibers, thermally expandable material, and a binder.
According to certain embodiments, the thermal insulation composite comprises a thermal insulation paper, thermal insulation board, and thermally expandable gasket comprising low biopersistent, inorganic fibers. According to certain embodiments, the low biopersistent fibers of the thermal insulation paper, thermal insulation board, and thermally expandable gasket comprise alkaline earth silicate fibers. According to certain embodiments, the alkaline earth silicate fibers of the thermal insulation paper, thermal insulation board, and thermally expandable gasket comprise magnesium-silicate fibers.
According to certain embodiments, the thermal insulation composite comprise a thermal insulation paper, thermal insulation board, and thermally expandable gasket comprise ceramic fibers. According to certain embodiments, the ceramic fibers of the thermal insulation paper, thermal insulation board, and thermally expandable gasket comprise alumino-silicate fibers. According to certain embodiments, the alumino-silicate fibers of the thermal insulation paper, thermal insulation board, and thermally expandable gasket comprise from about 45 to about 55 weight percent alumina and from about 55 to about 45 weight percent silica.
According to certain embodiments, the thermal insulation assembly comprises a thermal insulation paper and thermally expandable gasket comprising low biopersistent inorganic fibers, and a thermal insulation board comprising ceramic fibers. According to certain embodiments, the low biopersistent fibers of the thermal insulation paper and thermally expandable gasket comprise alkaline earth silicate fibers. According to certain embodiments, the alkaline earth silicate fibers of the thermal insulation paper and thermally expandable gasket comprise magnesium-silicate fibers. The ceramic fibers of the thermal insulation board comprise alumino-silicate fibers.
According to certain illustrative embodiments, the perimeter of support layer, the thermal insulation paper layer, and thermal insulation board layer are substantially coextensive. According to certain illustrative embodiments, the perimeter of the support layer, the thermal insulation paper layer, and thermal insulation board layer are coextensive.
According to certain illustrative embodiments, the perimeter of thermally expanding gasket layer and the retaining member are substantially coextensive. According to certain illustrative embodiments, the perimeter of thermally expanding gasket layer and the retaining member are coextensive.
According to certain illustrative embodiments, the perimeter of the support layer, the thermal insulation paper layer, and the thermal insulation board layer are substantially coextensive, and the perimeter of thermally expanding gasket layer and the retaining member are substantially coextensive, with the perimeters of the thermally expanding gasket layer and the retaining member being smaller than the support layer, the thermal insulation paper, and thermal insulation board.
According to certain illustrative embodiments, the perimeter of support layer, the thermal insulation paper layer, and thermal insulation board layer are coextensive, and the perimeter of thermally expanding gasket layer and the retaining member are coextensive, with the perimeters of the thermally expanding gasket layer and the retaining member being smaller than the support layer, the thermal insulation paper, and thermal insulation board.
According to certain embodiments, the retaining member of the thermal insulation composite includes a substantially circular retaining member. According to certain embodiments, the thermally expanding gasket of the thermal insulation system is substantially circular. The outer circumference of the thermally expandable gasket is substantially coextensive with the outer circumference of the circular retaining member.
The thermally insulating expanding gasket of the thermally insulating expanding gasket layer of the composite comprises a thickness that is defined by the opposite facing first and second major surfaces. In order to accommodate the expansion and contraction experienced by the solar thermal energy generation system as a result of thermal cycling, the thermally insulating expanding gasket is installed in the thermal insulation composite under compression.
While the thermal insulation composite, solar tower, solar energy system, and method have been described in connection with various illustrative embodiments, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function. Furthermore, the various illustrative embodiments may be combined to produce the desired results. Therefore, thermal insulation system, solar tower and solar energy system should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims. It will be understood that the embodiments described herein are merely exemplary, and that one skilled in the art may make variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as described hereinabove. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired result.
This application claims the benefit of the filing date under 35 U.S.C. §119(e) from U.S. Provisional Application for Patent Ser. No. 62/279,957 filed Jan. 18, 2016, which is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62279957 | Jan 2016 | US |
