Co-Simulation of Dynamic Underground Heat Transfer with Building Energy Modeling based on Equivalent Slab Method

Abstract Ground-coupled building envelopes contribute to up to 45% of total building heat loss. Dynamic simulation of the thermal process of the building-ground structure is essential for whole-year building energy simulations and evaluations. There exist various types of underground heat transfer models, while the adoption of dynamic underground heat transfer models in building energy simulation software is quite limited because of accuracy or computational efficiency issues. To fill this gap, this research proposes a novel co-simulation framework for dynamic underground heat transfer with building energy models. An XGB regression model was developed for the calculation of the heat response coefficient of building-ground structures, based on which an equivalent slab model is proposed and integrated with the general building energy models. The proposed co-simulation model was validated using the detailed 3-dimensional finite difference method. It can be concluded from the validation results that the simulation errors of the inner surface temperature of ground-coupled envelopes do not exceed 0.6℃, while the computational speed is improved by 4000-20000 times. The proposed model was integrated into the building performance simulation software DeST for the whole-year dynamic simulation of building-ground structures.