Evaluation of heat transfer models for hollow blocks in whole-building energy simulations

Five models to simulate time-dependent heat transfer through constructive systems of building walls or roofs with internal air-cavities that are being implemented in whole-building energy simulation programs are evaluated by comparing their predictions with test measurements. The simulations are made using EnergyPlus. Comparisons of simulation and experimental results demonstrate that the equivalent-homogeneous-layer-set (EHLS) model, presented here as Model 4, that considers the two dimensional (2D) heat transfer mechanisms of conduction through the solid part, natural convection in the air inside the cavities and radiation between air-cavity surfaces, gives the best results. The second best results corresponds to Model 3 that considers all these heat transfer mechanisms but it is only one-dimensional (1D). The results of this model are close to that of Model 4, indicating that in this case of study the heat flows through the framing path and the in-cavity path are similar. The Model 2 that only considers conduction in 2D gives the third best results and the Model 1 that considers conduction but in 1D gives the worst results. Model 5 is generated from Model 3 but suppressing radiation, results indicate that for this case of study radiation has a significant contribution. (C) 2019 Elsevier B.V. All rights reserved.