Keywords: ISO 13786, dynamic thermal characteristics, periodic thermal transmittance, internal areal heat capacity, decrement factor, time shift

ThermalWall calculates the fundamental thermal characteristics of a wall composed of multiple homogeneous flat layers, whose inner and outer surfaces are submitted to sinusoidal variations of temperature and/or heat flow. This characteristics variables are: thermal transmittance, internal areal heat capacity (heat accumulating on the inner surface per unit area and unit change in temperature), periodic thermal transmittance modulus, ratio of inner to outer surface temperature (ratio of the amplitude of the temperature wave at the inner surface to the amplitude of the temperature wave at the outer surface, when the heat passing through the inner surface is constant), decrement factor (ratio of periodic thermal transmittance modulus to thermal transmittance), time shift of periodic thermal transmittance (time shift, anticipation if positive or delay if negative, of the heat flow wave on the inner surface with respect to the temperature wave on the outer surface, when the temperature of inner surface is constant), time shift between maximum temperature outside and inside (Time shift of the temperature wave on the inner surface with respect to the temperature wave on the outer surface, when the heat passing through the inner surface is constant). The quantities treated and numerical procedures conform those defined in the European Standard EN ISO 13786 December 2007 "Thermal performance of building components - Dynamic thermal characteristics - Calculation methods (ISO 13786:2007)".