A fast and accurate mean radiant temperature model for courtyards: Evidence from the Keyuan Garden in central Guangdong, China

摘要

Most models that simulate mean radiant temperature (Tmrt) for complex geometries are computationally expensive. We developed a fast and accurate Tmrt model for courtyards (CMRT) based on a parallelized quasi-physical algorithm. Here, we present the CMRT implementation, validate the model for Keyuan Garden in Central Guangdong, and compare model results and performance to ENVI-met and Ladybug Tools. The new model simulated Tmrt for various locations in the test bed courtyard with a root mean square error (RMSE) of 1.82 degrees C, outperforming Ladybug (5.00 degrees C) and ENVI-met (8.27 degrees C) and meeting the accuracy requirement for heat and cold stress. The CMRT model simulates Tmrt two orders of magnitude faster than ENVI-met and Ladybug Tools. Model performance increased with resolution of the domain and number of view facets. A sensitivity analysis shows that the solar beam fraction is the largest contributor to Tmrt after air temperature. Cloud cover has a non-linear effect on Tmrt, and every 1 degrees C increase in surrounding surface temperatures raises Tmrt by 0.28 degrees C. With faster simulations and reliable results, the CMRT model will facilitate future climate-resilient courtyard design.

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