Radiative cooling structure and method of using the same

Abstract

A radiative cooling structure for achieving day-time radiative cooling is disclosed. The radiative cooling structure includes reflective layers sandwiching an emissive layer. The emissive layer includes a polymer. The emissive layer includes non-polymer particles arranged or distributed in a matrix or non-matrix fashion. The reflective layers reflect solar light, and the emissive layer having the non-polymer particles transmits solar radiation and emits infrared radiation. The radiative cooling structure releases the heat in the form of thermal radiation and lowers or maintains the temperature of an object or surface the radiative cooling structure is in thermal contact with.

What is claimed is: 
     
         1 . A radiative cooling structure for achieving day-time radiative cooling, said radiative cooling structure comprising:
 reflective layers; and   an emissive layer, wherein said emissive layer sandwiches between said reflective layers,   wherein said reflective layers reflect solar light, and said emissive layer transmits solar radiation and emits infrared radiation, and wherein said radiative cooling structure releases the heat in the form of thermal radiation and lowers or maintains the temperature of an object or surface said radiative cooling structure is in thermal contact with.   
     
     
         2 . A radiative cooling structure for achieving day-time radiative cooling, said radiative cooling structure of  claim 1 , wherein said radiative cooling structure mitigates climate change by being designed to remove greenhouse gases already present in the atmosphere. 
     
     
         3 . The radiative cooling structure of  claim 1 , wherein said emissive layer comprises a polymer, and said reflective layers are made of a glass or metal or ceramic. 
     
     
         4 . The radiative cooling structure of  claim 1 , wherein said emissive layer comprises non-polymer particles arranged or distributed in a matrix or non-matrix fashion. 
     
     
         5 . The radiative cooling structure of  claim 1 , wherein said emissive layer and said non-polymer particles comprise absorption bands in an atmospheric window and do not exhibit absorption in the solar spectrum from 0.3 micrometres (μm) to 3 μm. 
     
     
         6 . The radiative cooling structure of  claim 1 , wherein said each of said reflective layers has a thickness of 20 nanometres (nm) to 1 micrometre (μm). 
     
     
         7 . The radiative cooling structure of  claim 3 , wherein said non-polymer particles come in spherical, ellipsoidal, polyhedral, rod-shaped, plate-shaped or irregular shape. 
     
     
         8 . The radiative cooling structure of  claim 3 , wherein said non-polymer particles are made of silicon dioxide (SiO2), calcium carbonate (CaCO3), titanium dioxide (TiO2), silicon carbide (SIC), zinc oxide (ZnO), alumina (Al2O3), and combination thereof. 
     
     
         9 . The radiative cooling structure of  claim 3 , wherein said non-polymer particles have a volume percentage ranging from 2% to 25% with an average size ranging from 3 micrometres (μm) to 30 μm. 
     
     
         10 . The radiative cooling structure of  claim 1 , wherein said radiative cooling structure comes in the form of a film, coating, a fabric, or a non-woven fabric. 
     
     
         11 . The radiative cooling structure of  claim 1 , wherein said emissive layer comprises a polymer selected from a group of 4-methyl-1-pentene polymer, a 4-methyl-1-pentene copolymer, polyvinyl fluoride, and polyethylene terephthalate. 
     
     
         12 . The radiative cooling structure of  claim 1 , wherein said emissive layer has a thickness ranging from 10 micrometres (μm) to 3 millimetres (mm). 
     
     
         13 . The radiative cooling structure of  claim 1 , wherein said radiative cooling structure emits 5-13 micrometres (μm) Infrared (IR) emission in an atmospheric window. 
     
     
         14 . The radiative cooling structure of  claim 1 , wherein said radiative cooling structure dispenses heat at an approximately 110 Watt per meter square, and allows said object or surface to remain 10-12° Celsius (° C.) lower than the ambient temperature. 
     
     
         15 . The radiative cooling structure of  claim 1 , wherein said radiative cooling structure retains a randomized micrometre-sized glass sphere Silicon Dioxide (SiO 2 ) structure that supports Infrared (IR) emission and consequently effective radiative cooling. 
     
     
         16 . The radiative cooling structure of  claim 1 , wherein said radiative cooling structure comprises a randomized, glass polymer hybrid metamaterial having a randomly distributed Silicon Dioxide (SiO 2 ) microsphere inclusions for large-scale radiative cooling. 
     
     
         17 . A radiative cooling structure for achieving day-time radiative cooling, said radiative cooling structure comprising:
 a first layer and a second layer, wherein each of said first layer and said second layer comprises a reflective layer or a non-reflective layer; and   an emissive layer, wherein said emissive layer comprises a polymer, and wherein said emissive layer sandwiches between said first layer and said second layer,   wherein said first layer and said second layer reflect solar light, and said emissive layer transmits solar radiation and emits infrared radiation, and wherein said radiative cooling structure releases the heat in the form of thermal radiation and lowers or maintains the temperature of an object or surface said radiative cooling structure is in thermal contact with.   
     
     
         18 . The radiative cooling structure of  claim 16 , wherein said emissive layer comprises non-polymer particles arranged or distributed in a matrix or non-matrix fashion. 
     
     
         19 . The radiative cooling structure of  claim 16 , wherein said emissive layer and said non-polymer particles comprise absorption bands in an atmospheric window and do not exhibit absorption in the solar spectrum from 0.3 micrometres (μm) to 3 μm. 
     
     
         20 . A method of providing a radiative cooling structure for achieving day-time radiative cooling, said method comprising the steps of:
 providing reflective layers;   providing an emissive layer;   sandwiching said emissive layer between said reflective layers such that said reflective layers reflect solar light, and said emissive layer transmits solar radiation and emits infrared radiation; and   releasing heat in the form of thermal radiation and lowering or maintaining the temperature of an object or surface said radiative cooling structure is in thermal contact with.