Introduction

　　Thermal resistance (R) and thermal conductance (C) of the materials are reciprocals of one another and can be

　　derived from thermal conductivity (k) and the thickness of the materials.

　　(1)

　　k=q L∕ΔT

　　Where,

　　L – Thickness of the specimen (m)

　　T – Temperature (K)

　　q – Heat flow rate (W/m2)

　　R-value – Thermal Resistance

　　Thermal resistance is the temperature difference, at steady state, between two defined surfaces of a material or

　　construction that induces a unit heat flow rate through a unit area, K⋅m2/W. According to this definition and Equation 1,

　　Equation 2, therefore, can be obtained.As indicated in Equation 2, the value of the thermal resistance can be determined

　　by dividing the thickness with thermal conductivity of the specimen.

　　(2)

　　R=ΔT/q=L/K

　　C-value – Thermal Conductance

　　Thermal conductance is the time rate of steady state heat flow through a unit area of a material or construction induced

　　by a unit temperature difference between the body surfaces, in W/m2⋅K. C-value, hence, is the reciprocal of the R-value and can be expressed as Equation (3).

　　(3)

　　C=q/ΔT=l/R=k/L

　　Consequently, the value of the thermal conductance can be calculated by dividing the thermal conductivity with the thickness

　　of the specimen.