The present invention includes a heat exchanger reactive to external and internal temperatures for carrying a working fluid, including two pairs of nested pipes; each pair including one pipe with a channel portion and a stress relief portion and a second pipe with just a channel portion, one of said pipes enclosing the other with an interference fit and both pipes having different coefficients of thermal expansion. The first pair of pipes positioned co-axially with and encompassing the second pair. A fluid is positioned in the space defined by the inner surface of outer pair of pipes and the outer surface of inner pair of pipes. The two pipe pairs have positions responsive to the internal and external temperatures in which the space defined by pipe pairs is either minimized or maximized by expansion and contraction of the pipe pairs caused by differences in coefficients of thermal expansion.

Selective solar absorbent coating and manufacturing method, with solar absorption and low emissivity properties. The coating comprises a substrate (1) of metal, dielectric or ceramic material, at least one highly reflective metal layer (2) in mid-far infrared applied to the substrate itself which provides low emissivity properties, a mufti-layer structure of alternating dielectric and metallic layers (3) of subnanometric thickness applied to the reflective metal layer and at least one dielectric layer (4) that acts as an anti-reflective layer for the solar spectrum. The coating is applicable as a selective absorbent coating in absorbent tubes for parabolic-trough solar collectors, in solar panels for hot water, heating or domestic cooling, both in the form of absorbent tubes and absorbent sheets, in capture systems in tower solar thermoelectric power plants, and in capture systems in Stirling disk systems.

Selective solar absorbent coating and manufacturing method, with solar absorption and low emissivity properties. The coating comprises a substrate (1) of metal, dielectric or ceramic material, at least one highly reflective metal layer (2) in mid-far infrared applied to the substrate itself which provides low emissivity properties, a mufti-layer structure of alternating dielectric and metallic layers (3) of subnanometric thickness applied to the reflective metal layer and at least one dielectric layer (4) that acts as an anti-reflective layer for the solar spectrum. The coating is applicable as a selective absorbent coating in absorbent tubes for parabolic-trough solar collectors, in solar panels for hot water, heating or domestic cooling, both in the form of absorbent tubes and absorbent sheets, in capture systems in tower solar thermoelectric power plants, and in capture systems in Stirling disk systems.

A method for arranging at least one functional layer suitable for a multilayer solar selective coating is disclosed in the present application. Particularly, the method provided allows depositing arrangements of conductive and dielectric layers as well as coatings of dielectrics onto a substrate. The method disclosed may be used to prepare functional coatings with optical properties such as absorbing layers, anti-reflective layers and diffusion barriers.

A method (100) for manufacturing a thermal absorber for a solar thermal collector includes arranging (120) a substrate of the thermal absorber on a vacuum coating line and depositing (160) by way of a physical vapour deposition on the substrate that is arranged on the vacuum coating line layers configured to absorb light.

A method (100) for manufacturing a thermal absorber for a solar thermal collector includes arranging (120) a substrate of the thermal absorber on a vacuum coating line and depositing (160) by way of a physical vapour deposition on the substrate that is arranged on the vacuum coating line layers configured to absorb light.

A transpired solar collector includes the follows. An absorber panel having a body formed of stainless steel; a surface layer of chromium oxide on an exterior face of the body through-holes formed through the body and surface layer, in which the surface layer has a thickness of at least 70 nanometres.

The present invention addresses the issue of providing an optical selective film that contributes to efficiently converting light into heat. This optical selective film is characterized in that: the optical selective film includes at least an Ag-containing layer, and an Ag diffusion prevention layer that is disposed adjacent to the Ag-containing layer; and the Ag diffusion prevention layer contains FeSi.sub.x (X=1 to 2).

The invention relates to a solar selective absorbing coating and a preparation method thereof. The solar selective absorbing coating comprises a substrate, an infrared reflective layer, an absorbing layer and an antireflective layer in sequence from bottom to surface. The absorbing layer consists of a first sublayer, a second sublayer and a third sublayer. The first sublayer and the second sublayer contain metal nitride, and the third sublayer is metal oxynitride. The first sublayer is in contact with the infrared reflective layer, and the third sublayer is in contact with the antireflective layer. The preparation method comprises: depositing an infrared reflective layer on a substrate; depositing an absorbing layer on the infrared reflective layer; and depositing the antireflective layer on the absorbing layer. According to the metal nitride (oxynitride) solar selective absorbing coating, the working temperature of the metal nitride (oxynitride) solar selective absorbing coating is increased, the preparation is simple, and the coating is suitable for large-scale production.

A method for providing a thermal absorber, which can be used in solar thermal collectors. The method includes a step of depositing on a substrate a first layer having a composition that comprises titanium, aluminium, nitrogen, and one of following elements: silicon, yttrium, cerium, and chromium. The method further optionally includes a step of depositing a second layer deposited on the first layer, the second layer having a composition including titanium, aluminium, nitrogen, oxygen and one of the elements of silicon, yttrium, cerium, and chromium, and a step of depositing a third layer having a composition including titanium, aluminium, silicon, nitrogen, and oxygen, the third layer being a top layer of the thermal absorber.