Tham khảo tài liệu 'các âm và cách nhiệt công trình', kỹ thuật - công nghệ, kiến trúc - xây dựng phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | temperature drop corresponds to XR Temperature variation in a single-layer component outside rendering thickness I k R m W mK M internal plastei r wall outside rendering 1 C 1 X 1 ud 1R u ả W m2K Principle of heat transfer through a component internal plaster wall example wall made from aerated concrete 500kg m3 300mm thick plastered and rendered 3 Calculation of the u value of a multilayer component example section through an attic area u rafter area u rafter field un. 4 Ul A U- a U u ia. 1 0 89 W m2K Calculation of the mean thermal insulation value for combined components temperature drop corresponds to R Temperature variation in a multilayer component layers shown in proportion to their individual thermal insulation values As 5 but with distorted representation to show temperature variation as a straight line temperature of the inner surface of the wall t wi increases as the thermal insulation IS improved Temperature variation across variously insulated components for an internal temperature Oj 28 and outside air temperature f a -12 THERMAL INSULATION Terminology and Mechanisms Thermal insulation should minimise heat loss or gain allowing energy savings to be made provide a comfortable environment for occupants and protect a building from damage that might be caused by sharp temperature fluctuations in particular condensation . Heat exchange - by thermal convection conduction radiation and water vapour diffusion - cannot be prevented but its rate can be reduced by efficient thermal insulation. Terms used in calculating thermal insulation values Although temperature is often given in degrees Celsius C kelvin K is also used OK C . Quantity of heat is expressed in watt hours Wh . 1Wh . Thermal capacity the heat necessary to raise the temperature of 1 kg of material by 1 K is a measure of the readiness to respond to internal heat or to changing