A radiation device or the like has a structure for selectively converting thermal energy into an electromagnetic wave. The radiation device has a conductor layer, a semiconductor layer, and a plurality of conductor disks. The plurality of conductor disks are arranged on the semiconductor layer so that the same arrangement pattern is constituted in each of a plurality of unit constituent regions each having a rectangular shape with a side of 4.5 to 5.5 μm. The arrangement pattern of individual unit components includes nine conductor disks so as to correspond to a 3×3 matrix, and the nine conductor disks include four or more kinds of conductor disks having diameters different from each other. As a result, a two-dimensional periodic structure of the arrangement pattern is formed on the semiconductor layer.

Systems according to the present disclosure provide one or more surfaces that function as power radiating surfaces for which at least a portion of the radiating surface includes or is composed of “fractal cells” placed sufficiently closed close together to one another so that a surface wave causes near replication of current present in one fractal cell in an adjacent fractal cell. The fractal cells may lie on a flat or curved sheet or layer and be composed in layers for wide bandwidth or multibandwidth transmission. The area of a surface and its number of fractals determines the gain relative to a single fractal cell. The boundary edges of the surface may be terminated resistively so as to not degrade the cell performance at the edges. The fractal plasmonic surfaces can be utilized to facilitate electrical conduction with lower ohmic resistance than would otherwise be possible in the absence of the fractal plasmonic surface(s) at the same temperature.

Various aspects as described herein are directed to a radiative cooling device and method for cooling an object. As consistent with one or more embodiments, a radiative cooling device includes a solar spectrum reflecting structure configured and arranged to suppress light modes, and a thermally-emissive structure configured and arranged to facilitate thermally-generated electromagnetic emissions from the object and in mid-infrared (IR) wavelengths.

A cooling apparatus (1) for cooling a fluid by means of surface water, the cooling apparatus comprising at least one tube (8) for containing and transporting the fluid in its interior, the exterior of the tube (8) being in operation at least partially submerged in the surface water so as to cool the tube (8) to thereby also cool the fluid, characterized in that the cooling apparatus is adapted to receive at least one light source (9) for producing light that hinders fouling, wherein, after the cooling apparatus has received the light source, the at least one light source (9) is dimensioned and positioned with respect to the tube (8) so as to cast anti-fouling light over the tubes' (8) exterior.

Systems according to the present disclosure provide one or more surfaces that function as power radiating surfaces for which at least a portion of the radiating surface includes or is composed of fractal cells placed sufficiently closed close together to one another so that a surface wave causes near replication of current present in one fractal cell in an adjacent fractal cell. The fractal cells may lie on a flat or curved sheet or layer and be composed in layers for wide bandwidth or multibandwidth transmission. The area of a surface and its number of fractals determines the gain relative to a single fractal cell. The boundary edges of the surface may be terminated resistively so as to not degrade the cell performance at the edges. Fractal plasmonic surface cards are described.

One embodiment can provide a meta-material system. The meta-material system can include a host system and an inclusion system embedded within the host system. At least one effective physical property of the meta-material system is modulated by an external stimulation, thereby facilitating the meta-material system to self-regulating an external perturbation.

Embodiments described herein relate to a system with an electroactive substrate, a plurality of nanoparticles, and a control unit. The plurality of nanoparticles deposited in communication with the electroactive substrate. The control unit is configured to manipulate a shape of the electroactive substrate between an unactuated mode and an actuated mode to change an absorption band or an emission band of the plurality of nanoparticles. When the electroactive substrate shape is manipulated, the absorption band or the emission band of the plurality of nanoparticles is changed to tune the system for a radiative cooling based on a current dominating wavelength.

An apparatus includes a substrate, at least one type of tuning material, and a composite material. The substrate has an interface surface or material that manifests, in response to light in a color spectrum, a particular color and a first thermal load. The particular color is associated with the first thermal load. The at least one type of tuning material manifests, in response to light in the color spectrum, the particular color and a second thermal load. The particular color is associated with the second thermal load. The first thermal load is different from the second thermal load. The composite material includes the interface surface or material and the at least one type of tuning material. The composite material manifests, in response to light in the color spectrum, the particular color and a tuned thermal load which is different than the first thermal load and the second thermal load.

Provided is a radiative cooling device that provides coloration of the radiative surface while maximally avoiding reduction in its radiative cooling performance due to absorption of solar light. An infrared radiative layer for radiating infrared light from a radiative surface and a light reflective layer disposed on the side opposite to the presence side of the radiative surface of the infrared radiative layer are provided in a mutually stacked state. The light reflective layer is arranged such that a first metal layer made of silver or silver alloy and having a thickness equal to or greater than 10 nm and equal to or less than 100 nm, a transparent dielectric layer and a second metal layer reflecting light transmitted through the first metal layer and the transparent dielectric layer are stacked in this order on the side closer to the infrared radiative layer. The transparent dielectric layer has a thickness that causes a resonance wavelength of the light reflective layer to be a wavelength included in wavelengths equal to or greater than 400 nm and equal to or less than 800 nm.

A passive cooling article is disposed on a substrate to cool the substrate. The article includes an outer layer having a high absorbance in the atmospheric window region of the electromagnetic spectrum and having a high transmittance in the solar region of the spectrum. The article also includes a reflector having a high reflectivity in the solar region of the spectrum. At least one of the outer layer and the reflector includes a fluoropolymer. Micro-sized particles or surface structures may be disposed in or on the outer layer or the reflector to improve absorbance. A metallic layer may be disposed between the fluoropolymer and the substrate to be cooled.