Equivalent slabs approach for simulating the thermal performance of thermal bridges in buildings

An equivalent slabs approach was developed to accurately and quickly compute thermal bridges in building structures. The heat transfer across the thermal bridges was decomposed into several heat transfer processes controlled by various kinds of boundary conditions. The physical phenomenon for each of the heat transfer processes with harmonic boundary condition was analyzed using Fourier Theory to define an equivalent slab for each process. The heat fluxes from the equivalent slabs to the rooms for unsteady boundary conditions were validated by finite difference calculations. The computational time of the thermal bridges method is much less than for existing methods. The results can be easily implemented into building energy software simulation packages.