The disclosed invention relates to solar-thermal receiver tubes for heating high-temperature fluids such as molten salts and oils, such as those used in conjunction with trough reflectors or concentric concentrators. The disclosed invention utilizes fused silica receiver tube assemblies that provide optical absorption by way of optically-absorbing media that is imbedded within the thermal transfer fluid, preferably comprising inorganic dyes that comprise pulverized thin film coatings or dissolved materials that are specifically designed for maximizing optical absorption. Alternatively, the chemistry of the transfer fluid can be modified to increase optical absorption, or the optically absorbing media may comprise fine powders with density preferably similar to the thermal transfer fluid, such as fine graphite powder; or, in another preferred embodiment, absorbing means within the heat transfer fluid comprise a solid absorbing element disposed along the central axis of the receiver tube's interior.

Solar thermal panel (1) for producing water, comprising a frame (2), a reflective solar concentration surface (3), a heat exchanger (10) which is positioned at the solar focusing axis (A) and comprising a container (11) comprising an ambient humidity desiccator material (11a), at least one opening (12), a first valve (13) which is positioned at the at least one opening (12) and selectively actuatable by moving from an open configuration to a closed configuration so as to selectively and reversibly allow the fluid-dynamic connection between the desiccator material (11a) and surrounding ambient air.

A solar collector can comprise: a polymeric housing; a polymeric cover attached to the housing defining an internal volume of the solar collector; a solar energy absorber attached to the housing and located within an area defined by the housing and the cover; wherein the housing comprises a flexible sealing member; and wherein the cover comprises a honeycomb structure.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400? C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 ?m to 15 ?m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400? C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 ?m to 15 ?m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

The disclosed invention relates to solar-thermal receiver tubes for heating high-temperature fluids such as molten salts and oils, such as those used in conjunction with trough reflectors or concentric concentrators. The disclosed invention utilizes fused silica receiver tube assemblies that provide optical absorption by way of optically-absorbing media that is imbedded within the thermal transfer fluid, preferably comprising inorganic dyes that comprise pulverized thin film coatings or dissolved materials that are specifically designed for maximizing optical absorption. Alternatively, the chemistry of the transfer fluid can be modified to increase optical absorption, or the optically absorbing media may comprise fine powders with density preferably similar to the thermal transfer fluid, such as fine graphite powder; or, in another preferred embodiment, absorbing means within the heat transfer fluid comprise a solid absorbing element disposed along the central axis of the receiver tube's interior.

The invention relates to a small solar cooker with thermal energy storage. The device comprises an insulated wall (11), a transparent surface (1), and a Fresnel lens (2). The focal length of the lens can be adjusted using an automatic mechanical system (3) (12) to follow the height of the sun. During pre-heating, the focal point (10) of the lens is located on a small copper reservoir (4) containing a phase-change material (6). This material is thermally recharged by two methods: the concentration of radiation by the lens and/or by an auxiliary resistor supplied by an alternating current (5). The heat accumulated in the small reservoir allows the oven to be used when the sun is not shining or to reduce the cooking time. The whole oven is linked to another automatic mechanical system to follow the path of the sun.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400? C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 ?m to 15 ?m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

A silica aerogel having a mean pore size less than 5 nm with a standard deviation of 3 nm. The silica aerogel may have greater than 95% solar-weighted transmittance at a thickness of 8 mm for wavelengths in the range of 250 nm to 2500 nm, and a 400? C. black-body weighted specific extinction coefficient of greater than 8 m.sup.2/kg for wavelengths of 1.5 ?m to 15 ?m. Silica aerogel synthesis methods are described. A solar thermal aerogel receiver (STAR) may include an opaque frame defining an opening, an aerogel layer disposed in the opaque frame, with at least a portion of the aerogel layer being proximate the opening, and a heat transfer fluid pipe in thermal contact with and proximate the aerogel layer. A concentrating solar energy system may include a STAR and at least one reflector to direct sunlight to an opening in the STAR.

A transparent sheet includes a texture in relief on a first of its main faces, such that, if n is the refractive index of the material including the texture, P.sub.m is the mean slope in degrees of the textured face and Y(q) is the percentage of the textured surface with a slope greater than q/(n1) in degrees, then the two cumulative conditions exist: Y(q)>3%+f(q) %*P.sub.m*(n1) and Y(q)>10%, with f(q)=24(3*q) and q=2 or 3.