| 释义 |
U-value
U-val•ue (ˈyuˌvæl yu)
n. a measure of the flow of heat through an insulating or building material: the lower the U-value, the better the insulating ability. Compare R-value. [1945–50; U, symbol for internal energy] U-value
U-value[′yü ‚väl·yü] (engineering) A measure of heat transmission through a building part or a given thickness of insulating material, expressed as the number of British thermal units that will flow in 1 hour through 1 square foot of the structure or material from air to air with a temperature differential of 1°F. U-valueA measure of the amount of heat that flows in or out of a substance under constant conditions when there is a 1-degree difference between the air within and outside a building. U-values are used in determining the performance of a glazing system or window assembly.thermal transmittance, U-valueThe time rate of heat flow per unit area under steady conditions from the fluid on the warm side of a barrier to the fluid on the cold side, per unit temperature difference between the two fluids. |