Investigating the Effect of Different Parameters on CHTC Using Wind-Tunnel Measurement and Computational Fluid Dynamics (CFD) to Develop CHTC Correlations for Mixed CHTCS

Abstract

ABSTRACTConvective Heat Transfer Coefficient (CHTC) is a determining factor in building energy simulation (BES) tools for building thermal calculations. The accuracy of CHTC calculation has a direct effect on building energy analysis.This study aims to assess the impact of multiple parameters, namely temperature difference, wind speed, and wind direction on CHTC of building exterior surfaces. Then the overall high accuracy correlation based on these parameters for CHTC is provided. According to the specified values for temperature and velocity, Richardson’s number range from 0.1 to 10, representing a mixed heat transfer. The simulated results are compared with a wind tunnel experiment for validation. The standard k-epsilon model is used for turbulence simulation. Several cases are numerically simulated, considering various velocities, wind directions, and temperature differences. Results indicate that the studied parameters could be ranked as velocity, building orientation, and temperature difference in the order of effectiveness. All of the correlations used in EnergyPlus software for the exterior surface of the building are compared with the presented correlation and simulated data. The comparison shows that the proposed expression could predict CHTC for various angles, velocities, and temperature differences with an error of below 3%.