A meshfree SPH–view-factor framework for coupled conduction and radiative exchange in obstructed building enclosures

Predicting comfort-relevant surface temperatures in building enclosures requires coupling heat conduction in the solid (or quiescent) medium with surface-to-surface radiation across the enclosed air, particularly when internal obstructions reshape the view factors governing the mean radiant temperature (MRT). We present a meshfree framework combining Smoothed Particle Hydrodynamics (SPH) for conduction with a discrete view-factor radiation model, with analytic ray-casting for cylindrical obstructions and adaptive Picard under-relaxation. A Newton-linearised variant enables convergence in highly obstructed radiation-dominated regimes where the baseline fails. Validation against analytical Laplace/Dirichlet–Robin solutions and view-factor benchmarks yields errors within 2.7%. A cylindrical column reduces the view factor between the hot and cold walls by 42.7%, consistently for concrete and air. In high-conductivity concrete, radiation modifies surface temperatures by up to 25 K relative to pure conduction. We distinguish this geometric pathway modification from its comfort impact: a winter configuration leaves MRT essentially unchanged, whereas a strong summer wall contrast shifts the local MRT by up to 0.9 K, with noticeable PMV/PPD changes.