Quantitative comparison of massive walls thermal response among commercial software

Simulating heat conduction in massive walls with commercial software is reported to cause numerical instability or reduced accuracy. As contribution to the discussion, we have simulated one-dimensional heat conduction in massive walls and their dynamic thermal responses to a step, a sinusoid and time se-ries in TRNSYS, EnergyPlus, Delphin and Matlab. As reference, we have used EN ISO 13786:2007 and a self-written Matlab response factor method imple-mentation. We have compared transient and steady-state wall surface temperatures and heat fluxes for two different accuracy settings using suitable metrics. Errors up to 1 kWh/(m2 month) have been observed.