Systems and methods for radiative cooling and heating are provided. For example, systems for radiative cooling can include a top layer including one or more polymers, where the top layer has high emissivity in at least a portion of the thermal spectrum and an electromagnetic extinction coefficient of approximately zero, absorptivity of approximately zero, and high transmittance in at least a portion of the solar spectrum, and further include a reflective layer including one or more metals, where the reflective layer has high reflectivity in at least a portion of the solar spectrum.

Systems and methods for radiative cooling and heating are provided. For example, systems for radiative cooling can include a top layer including one or more polymers, where the top layer has high emissivity in at least a portion of the thermal spectrum and an electromagnetic extinction coefficient of approximately zero, absorptivity of approximately zero, and high transmittance in at least a portion of the solar spectrum, and further include a reflective layer including one or more metals, where the reflective layer has high reflectivity in at least a portion of the solar spectrum.

A solar heat collector tube in which at least an infrared reflective layer, a sunlight-heat conversion layer and an anti-reflection layer are provided on the outer surface of a tube through the interior of which a heat medium can flow, wherein the infrared reflective layer in the solar heat collector tube is an Ag layer having Nb dispersed therein, the content of Nb being 0.1 at % to 31.8 at %.

A solar heat collector tube in which at least an infrared reflective layer, a sunlight-heat conversion layer and an anti-reflection layer are provided on the outer surface of a tube through the interior of which a heat medium can flow, wherein the infrared reflective layer in the solar heat collector tube is an Ag layer having Nb dispersed therein, the content of Nb being 0.1 at % to 31.8 at %.

Provided is a solar collector that captures and utilizes solar energy and includes a plurality of vacuum tubes which are disposed by extending horizontally and are disposed parallel to each other with a predetermined distance; and a reflection plate having a substantially planar shape, which reflects solar light on an opposite side of the sun with respect to the plurality of vacuum tubes, in which the reflection plate includes a reflection surface having a serrated section at a corresponding position between vacuum tubes adjacent to each other, and in the reflection surface, one face of a serration forms a first reflection surface that reflects the solar light to the vacuum tube on a lower side among the vacuum tubes adjacent to each other.

Provided is a solar collector that captures and utilizes solar energy and includes a plurality of vacuum tubes which are disposed by extending horizontally and are disposed parallel to each other with a predetermined distance; and a reflection plate having a substantially planar shape, which reflects solar light on an opposite side of the sun with respect to the plurality of vacuum tubes, in which the reflection plate includes a reflection surface having a serrated section at a corresponding position between vacuum tubes adjacent to each other, and in the reflection surface, one face of a serration forms a first reflection surface that reflects the solar light to the vacuum tube on a lower side among the vacuum tubes adjacent to each other.

A solar absorber coating for a receiver element of a solar thermal or thermodynamic system. An additional aspect is a receiver for solar thermal or thermodynamic systems comprising a coating. The receiver may be an evacuated receiver pipe or a non-evacuated or air-operating receiver pipe.

A solar absorber coating for a receiver element of a solar thermal or thermodynamic system. An additional aspect is a receiver for solar thermal or thermodynamic systems comprising a coating. The receiver may be an evacuated receiver pipe or a non-evacuated or air-operating receiver pipe.

An austenitic steel alloy is provided having excellent corrosion resistance under high-temperature loading of more than 600° C. and up to 800° C., with the alloy having the following proposed chemical composition (in wt. %), consisting essentially of: C: 0.01 to 0.10; Si: max. 0.75; Mn: max. 2.00; P: max. 0.03; S: max. 0.03; Cr: 23 to 27; Ni: 17 to 23; Nb: 0.2 to 0.6; N: 0.15 to 0.35; the remainder being Fe and melting-related impurities. In a particular configuration a tubular body is made from this steel alloy, where an absorber pipe of a solar receiver of a solar power installation may be made from the tubular body. Still further, a solar receiver comprising this absorber pipe is provided, as well as a method for producing a tubular body from the steel alloy.

Systems and methods for radiative cooling and heating are provided. For example, systems for radiative cooling can include a top layer including one or more polymers, where the top layer has high emissivity in at least a portion of the thermal spectrum and an electromagnetic extinction coefficient of approximately zero, absorptivity of approximately zero, and high transmittance in at least a portion of the solar spectrum, and further include a reflective layer including one or more metals, where the reflective layer has high reflectivity in at least a portion of the solar spectrum.