Dynamic three-dimensional heat transfer calculation for uninsulated slab-on-ground constructions

Analytical solutions for two-dimensional steady-state and transient heat transfer from exterior ground surface are obtained for uninsulated slab-on-ground constructions. Approximate three-dimensional steady-state and transient heat transfer expressions are constructed. It is demonstrated that the approximate three-dimensional expressions give heat transfer results in satisfactory agreement with the analytical solutions and verified numerical models for the IEA BESTEST cases. The computation time for an annual simulation of the hourly floor heat transfer for the IEA BESTEST cases was found to be less than 0.1 s on a 2.6 GHz laptop computer. The proposed approximate expressions can be conveniently implemented in dynamic building simulation tools for fast ground-coupled heat transfer calculation.

► Provided a method for fast transient ground-coupled heat transfer calculation.
► Provided analytical 2D and approximate 3D steady and transient expressions.
► Approximate 3D transient expressions were verified with IEA BESTEST.
► Provided the methodology for implementation in building simulation tools.