Fast and dynamic urban neighbourhood energy simulation using CFDf-CFDc-BES coupling method

Building energy simulation (BES) tools show limitations in calculations of the convective heat transfer exchange with the surrounding urban areas. Therefore, dynamic coupling of BES to computational fluid dynamics (CFD) techniques is a common strategy to improve the simulation performance. Nonetheless, dynamic coupling itself is understood to be computationally intensive and unaffordable even in simplistic neighbourhood-scale scenarios.This paper proposes a novel framework for integration of a high-resolution CFD model (CFDf) into a coupled model of low-resolution CFD (CFDc) and BES. In specific, the CFDf model (fine grids) operates as the off-line component in the whole procedure that provides the boundary conditions, including the flow patterns, to CFDc (coarse grids) at the openings in the form of the mass flow information to BES to start the iterative process. After that, CFDc and BES domains execute a fully dynamic external coupling to deliver an accurate energy simulation.A case study is designed for a simple neighbourhood on a typical hot day for sheltered buildings with night-purge cooling. The results highlight in a significant improvement in results with representing neighbourhood effect and in a substantial reduction of computation cost of the dynamic coupling procedure