cooling material

Abstract

The present disclosure provides a cooling material which comprises a first spectrally selective component that comprises particles. The particles are arranged for emission of radiation predominantly having a wavelength or wavelength range within an atmospheric window wavelength range in which the atmosphere of the earth has a reduced average absorption and emission compared with an average absorption and emission in an adjacent wavelength range. Consequently, the cooling material is arranged for emission of thermal radiation and absorption of radiation from the atmosphere within that wavelength range is reduced. The cooling material further comprises a second spectrally selective component having a property that distinguishes the second spectrally selective component from the first spectrally selective component and facilitates at least one desired function of the cooling material.

1 . A cooling material which comprises:
 a first spectrally selective component comprising particles arranged for emission of radiation predominantly having a wavelength or wavelength range within an atmospheric window wavelength range in which the atmosphere of the earth has a reduced average absorption and emission compared with an average absorption and emission in an adjacent wavelength range whereby the cooling material is arranged for emission of thermal radiation and absorption of radiation from the atmosphere within that wavelength range is reduced; and   a second spectrally selective component having a property that distinguishes the second spectrally selective component from the first spectrally selective component and facilitates at least one desired function of the cooling material.   
     
     
         2 . The cooling material of  claim 1  wherein the second spectrally selective component is arranged to facilitate cooling of the cooling material. 
     
     
         3 . The cooling material of  claim 1  or  2  wherein the second spectrally selective component is arranged for emission of radiation by a physical process that is identical to that associated with the emission of radiation by the particles of the first spectrally selective components but at a wavelength or wavelength range that differs from that of the first spectrally selective component. 
     
     
         4 . The cooling material of  claim 1  or  2  wherein the second spectrally selective component is arranged for emission of radiation by a physical process that differs to that associated with the emission of radiation by the particles of the first spectrally selective component. 
     
     
         5 . The cooling material of  claim 1  or  2  wherein the second spectrally selective component is arranged for absorption of radiation. 
     
     
         6 . The cooling material of any one of the preceding claims wherein the particles of the first spectrally selective component are arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         7 . The cooling material of  claim 6  wherein the particles of the first spectrally selective component are arranged so that at least some of the ionic surface plasmons have a wavelength within at least one of the wavelength range from 1-7 μm, 2-6 μm and 3-5 μm; and/or at least one of 5-16 μm, 7-14 μm, 8-13 μm and 7.9-13 μm. 
     
     
         8 . The cooling material of  claim 6  or  7  wherein the particles of the first spectrally selective component are arranged so that the ionic surface plasmons are generated at a wavelength range that is partially outside the atmospheric window wavelength range. 
     
     
         9 . The cooling material of any one of the preceding claims wherein the particles of the first spectrally selective component comprise SiC. 
     
     
         10 . The cooling material of any one of  claims 1 - 5  wherein the particles of the first spectrally selective component are arranged for emission of radiation by a physical mechanisms other than that associated with the generation of ionic surface plasmons. 
     
     
         11 . The cooling material of  claim 10  wherein the particles of the first spectrally selective component comprise SiO or silicon oxynitride. 
     
     
         12 . The cooling material of any one of the preceding claims wherein the second spectrally selective component comprise particles. 
     
     
         13 . The cooling material of  claim 12  wherein the particles of the first spectrally selective component and the particles of the second spectrally selective component are dispersed within another component. 
     
     
         14 . The cooling material of  claim 12  or  13  wherein the particles of the second spectrally selective component are arranged for emission of radiation having a wavelength within the atmospheric window wavelength range. 
     
     
         15 . The cooling material of any one of  claims 12  to  14  wherein the particles of the second spectrally selective component are arranged for emission of radiation by generation of ionic surface plasmons. 
     
     
         16 . The cooling material of  claim 12  or  13  wherein the particles of the second spectrally selective component are arranged for emission of radiation by a physical mechanisms other than that associated with the generation of ionic surface plasmons. 
     
     
         17 . The cooling material of  claim 16  wherein the particles of the second spectrally selective component comprise SiO or silicon oxynitride. 
     
     
         18 . The cooling material of  claim 16  wherein the particles of the second spectrally selective component are arranged for absorbing radiation by generating electronic surface plasmons. 
     
     
         19 . The cooling material of any one of  claims 1  to  11  wherein the second spectrally selective component comprises a layer. 
     
     
         20 . The cooling material of any one of the preceding claims comprising a polymeric material that is transmissive for radiation of a predetermined range. 
     
     
         21 . The cooling material of  claim 20  wherein at least a portion of the cooling material is of a clear appearance. 
     
     
         22 . The cooling material of  claim 20  wherein the cooling material is of an opaque appearance. 
     
     
         23 . The cooling material of  claim 19  wherein the particles of the first spectrally selective component are be embedded in or positioned adjacent the layer. 
     
     
         24 . The cooling material as claimed in any one of  claims 1  to  20  or  claim 23  wherein the cooling material is arranged to reflect at least some incident radiation. 
     
     
         25 . The cooling material of  claim 24  comprising a reflective layer. 
     
     
         26 . The cooling material of  claim 24  comprising reflective particles that are dispersed within an at least partially transparent material. 
     
     
         27 . The cooling material of any one of  claims 24  to  26  wherein the cooling material is arranged so that the majority of incident radiation is reflected. 
     
     
         28 . The cooling material of any one of  claims 24  to  26  wherein the cooling material also reflects incident radiation having a wavelength within the atmospheric window wavelength range. 
     
     
         29 . The cooling material of  claim 1  wherein the particles of the first spectrally selective component are arranged for generation of ionic surface plasmons and the second spectrally selective component comprises particles that are also arranged for generation of ionic surface plasmons at a wavelength or wavelength range that differs from that of the particles of the first spectrally selective component. 
     
     
         30 . The cooling material of  claim 1  wherein the particles of the first spectrally selective component are arranged for generation of ionic surface plasmons and the second spectrally selective component comprises particles that are arranged for generation of electronic surface plasmons. 
     
     
         31 . The cooling material of  claim 30  wherein the second spectrally selective component comprises particles that are arranged for generation of electronic surface plasmons by absorption of radiation in the near infrared (NIR) wavelength. 
     
     
         32 . The cooling material of  claim 31  wherein the cooling material is arranged so that a portion of the thermal energy, that is present as a consequence of the absorbed solar radiation in the infrared (NIR) wavelength range, is emitted by the particles of the first spectrally selective component. 
     
     
         33 . The cooling material of  claim 30  wherein the second spectrally selective component is arranged for generation of electronic surface plasmons having wavelengths at or near the visible wavelength range. 
     
     
         34 . The cooling material of any one of the preceding claims comprising a layered structure that is arranged to reflect thermal radiation from the atmosphere or a portion of visible light. 
     
     
         35 . A cooling material which comprises:
 a spectrally selective component comprising at least one layer arranged for receiving thermal energy and emitting at least a portion of the received thermal energy in the form of the thermal radiation, the thermal radiation predominantly having a wavelength or wavelength range within an atmospheric window wavelength range in which the atmosphere of the Earth has a reduced average absorption and emission compared with an average absorption and emission in an adjacent wavelength range whereby absorption of radiation from the atmosphere is reduced.   
     
     
         36 . The cooling material of  claim 35  wherein the spectrally selective component is a first spectrally selective component, the cooling material further comprising a second spectrally selective component having a property that distinguishes the second spectrally selective component from the first spectrally selective component and facilitates at least one desired function of the cooling material. 
     
     
         37 . The cooling material of  claim 35  or  36  wherein the second spectrally selective component is arranged to facilitate cooling of the cooling material. 
     
     
         38 . The cooling material of any one of  claims 35  to  37  wherein the atmospheric window wavelength range is a wavelength range from 3 to 5 μm and/or from 7.9 μm to 13 μm. 
     
     
         39 . The cooling material of any one of  claims 35  to  38  wherein the at least one layer is arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         40 . The cooling material of any one of  claims 35  to  39  wherein the at least one layer has a structural property that is selected so that the at least one layer is arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         41 . The cooling material of  claim 40  wherein the at least one layer comprises grains and wherein the structural property is associated with a diameter of the grains and the grain diameter is selected so that the at least one layer is arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         42 . The cooling material of  claim 40  wherein the at least one layer comprises pores and wherein the structural property is associated with a thickness of residual solid the between the pores and wherein the thickness of the residual solid between the pores is selected so that the at least one layer is arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         43 . The cooling material of  claim 40  wherein the at least one layer has a surface roughness and wherein the structural property is associated with a thickness or width of surface features of the surface of the at least one layer and wherein the thickness or width of the surface features is selected so that the at least one layer is arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         44 . The cooling material of  claim 40  wherein the at least one layer is a part of a multi-layered structure having layer thicknesses that are selected so that the multi-layered structure is arranged for generation of ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         45 . A method of cooling using a cooling material for emission of thermal energy, the cooling material comprising a first spectrally selective component and a second spectrally selective component, the second spectrally selective component having a property that distinguishes the second spectrally selective component from the first spectrally selective component, the method comprising:
 emitting a portion of the thermal energy from the first spectrally selective component in the form of radiation having a wavelength within the atmospheric window wavelength range in which the atmosphere of the earth has low or negligible average absorption and emission compared with the average absorption and emission in an adjacent wavelength range; and   emitting a portion of the thermal energy from the second spectrally selective component.   
     
     
         46 . The method of  claim 45  wherein the first spectrally selective component comprises particles arranged for emitting a portion of the thermal energy in the form of radiation having a wavelength within the atmospheric window wavelength range. 
     
     
         47 . The method of  claim 45  wherein the first spectrally selective component comprises at least one layer arranged for emitting a portion of the thermal energy in the form of radiation having a wavelength within the atmospheric window wavelength range. 
     
     
         48 . The method of any one of  claims 45  to  47  wherein emitting a portion of the thermal energy from the second spectrally selective component comprises emitting radiation by a physical process that is identical to that associated with the emission of radiation by the first spectrally selective component, but at a wavelength or wavelength range that differs from that of the first spectrally selective component. 
     
     
         49 . The method of any one of  claims 45  to  47  wherein emitting a portion of the thermal energy from the second spectrally selective component comprises emitting radiation by a physical process that differs to that associated with the emission of radiation by the first spectrally selective component. 
     
     
         50 . The method of any one of  claims 45 - 49  wherein emitting a portion of the thermal energy from the first spectrally selective component comprises generating ionic surface plasmon resonances having a wavelength or wavelength range within the atmospheric window wavelength range. 
     
     
         51 . The method of  claim 50  wherein emitting a portion of the thermal energy from the first spectrally selective component is conducted so that at least some of the ionic surface plasmons have a wavelength within at least one of the wavelength range from 1-7 μm, 2-6 μm and 3-5 μm; and/or within at least one of 5-16 μm, 7-14 μm, 8-13 μm and 7.9-13 μm. 
     
     
         52 . The method of any one of  claims 45  to  49  wherein emitting a portion of the thermal energy from the first spectrally selective component comprises generating the ionic surface plasmons at a wavelength range that is partially outside the atmospheric window wavelength range. 
     
     
         53 . The method of any one of  claims 45  to  52  wherein emitting a portion of the thermal energy from the second spectrally selective component comprises emitting radiation having a wavelength within the atmospheric window wavelength range. 
     
     
         54 . The method of  claim 48  wherein emitting a portion of the thermal energy from the second spectrally selective component comprises emitting radiation by generation of ionic surface plasmons. 
     
     
         55 . The method of any one of  claim 49  wherein emitting a portion of the thermal energy from the second spectrally selective component comprises absorbing radiation by generating electronic surface plasmons. 
     
     
         56 . The method of any one of  claims 48  to  55  comprising reflecting at least some incident radiation. 
     
     
         57 . The method of  claim 56  comprising reflecting incident radiation having a wavelength within the atmospheric window wavelength range. 
     
     
         58 . The method of any one of  claims 45  to  57  comprising controlling at least one of the composition of the first spectrally selective component and a structural property of the first spectrally selective component to control the wavelength range of ionic surface plasmons.