A material may be included in a cooling film or cooling panel to achieve cooling even under direct solar irradiation. The material includes one or more constituent materials and an outer surface configured to interact thermally with the atmosphere and with solar radiation. The material exhibits an emissivity of at least 0.8 in spectral range of 5 μm to 15 μm, an ultraviolet reflectivity of at least 0.5 in the spectral range of 275 nm to 375 nm, an ultraviolet absorptivity of at least 0.75 in the spectral range of 275 nm to 375 nm, or a combination thereof. A cooling film, or cooling panel, may be affixed to an exterior surface of a vehicle, structure, or system to provide cooling even under direct solar irradiance.

The present invention provides a solar absorber incorporated bilayer foam solar evaporator for seawater and wastewater purification including a plurality of solar absorbers partially incorporated into a porous polymer framework and partially forming a thermal insulation layer proximal to solar irradiation. In particular, low-cost commercially available B.sub.4C powders are embedded into a porous polymer foam in a one-pot method to form a scaffold of boron carbide bilayer foam (BCBF) with good hydrophilic wettability, heat-shielding, and solar-thermal conversion. The boron carbide bilayer foam (BCBF) of the present invention enables a high cost-performance seawater desalination and wastewater purification at a high evaporation rate of 2.8 kg/m.sup.2/h with 93% solar evaporation efficiency under 1 sun illumination (or 1 kW/m.sup.2). The present invention thereby provides an excellent and cost-effective solar evaporator tool for industrial-level water purification. Following the present method to prepare the BCBF solar evaporator, the fabrication cost can be as low as 3.6 $/m.sup.2.

The present invention provides a solar absorber incorporated bilayer foam solar evaporator for seawater and wastewater purification including a plurality of solar absorbers partially incorporated into a porous polymer framework and partially forming a thermal insulation layer proximal to solar irradiation. In particular, low-cost commercially available B.sub.4C powders are embedded into a porous polymer foam in a one-pot method to form a scaffold of boron carbide bilayer foam (BCBF) with good hydrophilic wettability, heat-shielding, and solar-thermal conversion. The boron carbide bilayer foam (BCBF) of the present invention enables a high cost-performance seawater desalination and wastewater purification at a high evaporation rate of 2.8 kg/m.sup.2/h with 93% solar evaporation efficiency under 1 sun illumination (or 1 kW/m.sup.2). The present invention thereby provides an excellent and cost-effective solar evaporator tool for industrial-level water purification. Following the present method to prepare the BCBF solar evaporator, the fabrication cost can be as low as 3.6 $/m.sup.2.

Ceramic particles for use in a solar power tower and methods for making and using the ceramic particles are disclosed. The ceramic particle can include a sintered ceramic material formed from a mixture of a raw material and MnO. The sintered ceramic material can include about 0.01 wt % to about 10 wt % MnO, about 0.1 wt % to about 20 wt % Fe.sub.2O.sub.3, and about 0.01 wt % to about 10 wt % Mn.sub.2O.sub.3. The ceramic particle can have a size from about 8 mesh to about 170 mesh.

Ceramic particles for use in a solar power tower and methods for making and using the ceramic particles are disclosed. The ceramic particle can include a sintered ceramic material formed from a mixture of a raw material and MnO. The sintered ceramic material can include about 0.01 wt % to about 10 wt % MnO, about 0.1 wt % to about 20 wt % Fe.sub.2O.sub.3, and about 0.01 wt % to about 10 wt % Mn.sub.2O.sub.3. The ceramic particle can have a size from about 8 mesh to about 170 mesh.

Multi-effect-distillation (MED) systems of several designs are among the most energy-efficient technologies used in seawater desalination, throughout the world today; typically, energy consumed being <15 kWh / m^3 distillate produced. One caveat in all MED systems is the disposition of the brine-waste reject product with respect to the environment; per unit volume fresh water produced, typically, two units of waste brine media with salinity in excess of 50 g/l, must be dispersed responsibly. Herein is described a MEDX design coupled with thermal-vapor-expanders (TVX) utilizing energy recovered in said brine-waste media, wherein salt-gradient-solar-ponds (SGSP) are used alongside molten salts single-temperature thermal energy storage (SITTES) as principle thermal energy sources (TES) redirected to the MEDX plant, 24/7. Quantifiable electric power production and an additional ~2500 m^3/d distillate, is attained above that produced in a hypothetical 20-effect MEDX plant thru recycling said waste brines into said 20-effect MEDX plant, integrating both flash-chambers (FC) and negative pressure tanks (NPT) in the fore and end-stages, respectively of said MEDX plant.

Multi-effect-distillation (MED) systems of several designs are among the most energy-efficient technologies used in seawater desalination, throughout the world today; typically, energy consumed being <15 kWh / m^3 distillate produced. One caveat in all MED systems is the disposition of the brine-waste reject product with respect to the environment; per unit volume fresh water produced, typically, two units of waste brine media with salinity in excess of 50 g/l, must be dispersed responsibly. Herein is described a MEDX design coupled with thermal-vapor-expanders (TVX) utilizing energy recovered in said brine-waste media, wherein salt-gradient-solar-ponds (SGSP) are used alongside molten salts single-temperature thermal energy storage (SITTES) as principle thermal energy sources (TES) redirected to the MEDX plant, 24/7. Quantifiable electric power production and an additional ~2500 m^3/d distillate, is attained above that produced in a hypothetical 20-effect MEDX plant thru recycling said waste brines into said 20-effect MEDX plant, integrating both flash-chambers (FC) and negative pressure tanks (NPT) in the fore and end-stages, respectively of said MEDX plant.

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 %.

A gas receiver configured to heat a working fluid is disclosed. The receiver comprises an aperture, a light absorber, and a pre-heater interposed between the aperture and light absorber. The pre-heater is transparent to visible light and opaque to infrared. The pre-heater in the preferred embodiment comprises quartz in the form of a plurality of quartz plates or quartz tubes, for example, that are oriented substantially parallel to one another. The quartz plates are separated from one another by a gap to permit air to pass into the receiver cavity, while the quartz tubes are hollow to permit air to pass therethrough. The quartz plates or tubes are configured to transmit visible light from the aperture to the light absorber, and to absorb infrared radiation passing from the light absorber toward the aperture. Since the quartz structures absorb infrared, they serve to capture blackbody radiation emitted from the absorber and use that energy to pre-heat air before it passes into the absorber.