Modelling of wall heat transfer using modified conduction transfer function, finite volume and complex Fourier analysis methods

The original conduction transfer function (CTF) method (which was derived from the EnergyPlus source codes), and the present modified CTF method (which uses a higher order discretisation scheme for the surface heat flux as well as finer grids at the layer boundaries for multi-layer constructions) were used to calculate wall surface heat fluxes based on monitored wall surface temperatures as the inputs. At the same time, the finite volume method and the matrix method (based on the complex Fourier analysis) were also used for the numerical predictions. The matrix transfer method was updated to treat the non-linear long wave length thermal radiation and proved to be consistent with the results from the finite volume method for all wall types ranging from single-layer wall, two-layer wall with air gap, cavity brick wall and brick veneer wall. Numerical predictions using the matrix transfer method, the conduction transfer function method and the finite volume method were compared with the long period measurements for single- or multi-layer materials with and without air gaps. At the same time, CTF coefficients for modified CTF methods were tabulated and analysed for all computational cases in this study.