space exploration

As part of the Apollo program, NASA helped develop a thin film of aluminum, which reflected 95% of radiant heat.[1] A metallized film was used to protect spacecraft, equipment, and astronauts from thermal radiation or to help regulate heat loss or absorption in the face of extreme temperature fluctuations in outer space.[1] A small amount of aluminum was deposited in a vacuum atmosphere to form a thin film on a base material, this material resembling cloth or paper. It was placed on the outer surface of the Apollo vehicles that landed on the moon, in addition to being used in numerous other NASA projects such as the James Webb Space Telescope and Skylab. In the vacuum of space where temperatures range from more than 250 °F to 400 °F below zero,[2] heat transfer can only take place through radiation, so a radiant barrier is much more effective than it is on Earth, where depending on the circumstances between 5% to 45% of heat transfer can occur through convection and conduction phenomena, even when an effective radiant barrier has been placed. The radiant barrier[2]​ has been recognized as an important development from space technology that has been adapted for use on Earth.

Textiles

Since the 1970s,[1] it has been possible to purchase metallized polyester blankets called thermal blankets, which are used to prevent hypothermia and other problems derived from exposure to low temperatures. Due to their durability and being extremely lightweight, these blankets are popular as part of survival and first aid kits. For example, a large group of people may be wrapped in foil after finishing a marathon, especially when temperatures are particularly cold, such as during the annual New York City Marathon in the fall.

Glass treatments

It is possible to apply coatings to the glass used in windows in order to reduce its emissivity. Some glasses use a laminated polyester film where at least one layer of metal has been deposited using a process called sputtering. Sputtering is a process in which a metal, usually aluminum, is vaporized and a film (may be polyester) is exposed to said atmosphere. This process can be regulated to control the amount of metal that is ultimately deposited on the film surface.

These metallized layers are deposited on one or more surfaces of the glass in order to increase the resistance to heat transfer by radiation, however the metal layers are so thin that they allow visible light to pass through them. Since thin coating films are fragile, and can be damaged by exposure to air and steam, manufacturers generally use glasses composed of several plates, between which they sandwich the thin films. Some types of glass coating films can be applied "in situ" at home; these types of films have an average lifespan of about 10 to 15 years.[3]​.

Roofs and attics

Solar radiation hits the roof, heating the shingles, and then conduction the insulating and structural material that makes up the roof, causing the underside of the roof and its structures to radiate heat downward through the attic to the attic floor. When a radiant barrier is placed between the roofing material and the attic floor insulation, much of the heat radiated by the hot roof is reflected back toward the roof and because of the low emissivity of the underside of the radiant barrier a small percentage of the heat is ultimately emitted downward. This way the top of the insulation material is cooler than it would be if there were no radiant barrier and therefore reduces the amount of heat transmitted through the insulation material to the rooms below the ceiling.

space exploration

As part of the Apollo program, NASA helped develop a thin film of aluminum, which reflected 95% of radiant heat.[1] A metallized film was used to protect spacecraft, equipment, and astronauts from thermal radiation or to help regulate heat loss or absorption in the face of extreme temperature fluctuations in outer space.[1] A small amount of aluminum was deposited in a vacuum atmosphere to form a thin film on a base material, this material resembling cloth or paper. It was placed on the outer surface of the Apollo vehicles that landed on the moon, in addition to being used in numerous other NASA projects such as the James Webb Space Telescope and Skylab. In the vacuum of space where temperatures range from more than 250 °F to 400 °F below zero,[2] heat transfer can only take place through radiation, so a radiant barrier is much more effective than it is on Earth, where depending on the circumstances between 5% to 45% of heat transfer can occur through convection and conduction phenomena, even when an effective radiant barrier has been placed. The radiant barrier[2]​ has been recognized as an important development from space technology that has been adapted for use on Earth.

Textiles

Since the 1970s,[1] it has been possible to purchase metallized polyester blankets called thermal blankets, which are used to prevent hypothermia and other problems derived from exposure to low temperatures. Due to their durability and being extremely lightweight, these blankets are popular as part of survival and first aid kits. For example, a large group of people may be wrapped in foil after finishing a marathon, especially when temperatures are particularly cold, such as during the annual New York City Marathon in the fall.

Glass treatments

It is possible to apply coatings to the glass used in windows in order to reduce its emissivity. Some glasses use a laminated polyester film where at least one layer of metal has been deposited using a process called sputtering. Sputtering is a process in which a metal, usually aluminum, is vaporized and a film (may be polyester) is exposed to said atmosphere. This process can be regulated to control the amount of metal that is ultimately deposited on the film surface.

These metallized layers are deposited on one or more surfaces of the glass in order to increase the resistance to heat transfer by radiation, however the metal layers are so thin that they allow visible light to pass through them. Since thin coating films are fragile, and can be damaged by exposure to air and steam, manufacturers generally use glasses composed of several plates, between which they sandwich the thin films. Some types of glass coating films can be applied "in situ" at home; these types of films have an average lifespan of about 10 to 15 years.[3]​.

Roofs and attics

Solar radiation hits the roof, heating the shingles, and then conduction the insulating and structural material that makes up the roof, causing the underside of the roof and its structures to radiate heat downward through the attic to the attic floor. When a radiant barrier is placed between the roofing material and the attic floor insulation, much of the heat radiated by the hot roof is reflected back toward the roof and because of the low emissivity of the underside of the radiant barrier a small percentage of the heat is ultimately emitted downward. This way the top of the insulation material is cooler than it would be if there were no radiant barrier and therefore reduces the amount of heat transmitted through the insulation material to the rooms below the ceiling.