thermal+insulation

=Thermal insulation= From Wikipedia, the free encyclopedia

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Thermal insulation on the [|Huygens probe] [|Mineral wool] Insulation, 1600 dpi scan against the grain [|Mineral wool] Insulation, 1600 dpi scan with the grain Heat flow is an inevitable consequence of contact between objects of differing temperature. Thermal insulation provides a means to maintain a gradient of temperature, by providing a region of insulation in which heat flow is reduced or [|thermal radiation] is reflected rather than absorbed. In building construction, insulating materials are assigned a quantitative measure of the insulating capability, called the [|R-value]. [[|hide]]
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 * Thermal insulation** is the reduction of the effects of the various processes of [|heat transfer] between objects in thermal contact or in range of radiative influence. [|Heat] is the transfer of [|thermal energy] between objects of differing temperature. The means to stem heat flow may be especially engineered methods or processes, as well as suitable static objects and materials.
 * ==Contents==
 * [|1] [|Applications]
 * [|1.1] [|Clothing]
 * [|1.2] [|Buildings]
 * [|1.3] [|Mechanical systems]
 * [|1.4] [|Spacecraft]
 * [|1.5] [|Automotive]
 * [|2] [|Factors influencing performance]
 * [|3] [|Calculating requirements]
 * [|4] [|See also]
 * [|5] [|References] ||

[[|edit]] Clothing
Clothing is chosen to maintain the temperature of the human body. To offset high ambient heat, clothing must enable sweat to evaporate (cooling by evaporation). When humans anticipate high temperatures and physical exertion, the billowing of fabric during movement creates air currents that increase evaporation and cooling. A layer of fabric insulates slightly and keeps skin temperatures cooler than otherwise. To combat cold, evacuating skin humidity is still essential while several layers of materials with different properties are necessary to simultaneously achieve this goal while matching one's internal heat production to the heat losses that occur. The key is layering for different purposes, as heat loss occurs due to wind, radiation of heat into space and conductive bridging. The latter is most apparent in footwear where insulation against conductive heat loss is most important.

[[|edit]] Buildings
Main article: [|Building insulation] Common insulation applications in [|apartment] [|building] in [|Ontario], [|Canada]. Maintaining acceptable temperatures in buildings (by heating and cooling) uses a large proportion of global energy consumption. When well insulated, a [|building]: Many forms of thermal insulation also reduce [|noise] and vibration, both coming from the outside and from other rooms inside a building, thus producing a more comfortable environment. [|Window insulation film] can be applied in [|weatherization] applications to reduce incoming thermal radiation in summer and loss in winter. In industry, energy has to be expended to raise, lower, or maintain the temperature of objects or process fluids. If these are not insulated, this increases the energy requirements of a process, and therefore the cost and environmental impact.
 * is energy-efficient, thus saving the owner money.
 * provides more uniform temperatures throughout the space. There is less temperature gradient both vertically (between ankle height and head height) and horizontally from exterior walls, ceilings and windows to the interior walls, thus producing a more comfortable occupant environment when outside temperatures are extremely cold or hot.
 * has minimal recurring expense. Unlike heating and cooling equipment, insulation is permanent and does not require maintenance, upkeep, or adjustment.

[[|edit]] Mechanical systems
Main article: [|Pipe insulation] Space heating and cooling systems distribute heat throughout buildings by means of pipe or ductwork. Insulating these pipes using [|pipe insulation] reduces energy into unoccupied rooms and prevents [|condensation] from occurring on cold and chilled pipework. [|Pipe insulation] is also used on water supply pipework to help delay pipe freezing for an acceptable length time.[|[][|1][|]]

[[|edit]] Spacecraft
Insulation for applications on spacecraft must be light-weight. In particular, spacecraft must be insulated against radiative heating from [|thermal radiation] as no means exist in space for convective cooling by the atmosphere. Outside the Earth's atmosphere, radiated energy from the Sun is greater than on Earth, and all surfaces exposed heat up quickly. Thermal radiation insulation often consists of [|multi-layer insulation] using special paints, foams, and layers of metal. Launch and re-entry place severe mechanical stresses on spacecraft, so the strength of an insulator is critically important (as seen by the failure of insulating foam on the [|Space Shuttle Columbia]). Re-entry through the atmosphere generates very high temperatures because of friction against air at high speeds. Insulators must meet demanding physical properties beyond their thermal transfer retardant properties. E.g. reinforced [|carbon]-carbon composite nose cone and [|silica] fiber tiles of the [|Space Shuttle]. See also [|Insulative paint].

[[|edit]] Automotive
Thermal insulation applied to exhaust component by means of plasma spraying Main article: [|Exhaust Heat Management] [|Internal combustion engines] produce a lot of heat during their combustion cycle. This can have a negative effect when it reaches various heat-sensitive components such as sensors, batteries and starter motors. As a result, thermal insulation is necessary to prevent the heat from the exhaust reaching these components.[|[][|2][|]] High performance cars often use thermal insulation as a means to increase engine performance.