Outdoor Micro-Climate Analysis of Green Buildings on Environmental Affects Using PALM Software

This paper aims to analyses the effect of green buildings on the environment, which is currently affected by climate change. PALM or parallelized large-eddy simulation model was applied in order to simulate the urban vegetation on the outdoor thermal environment. The model solved the non-hydrostatic incompressible Navier-Stokes equation. There were 9 cases in total with 3 different design categories; 3 cases are for Conventional Building (nonvegetation building), 3 cases are for Green Rooftop, and the other 3 cases are Green Floor (no building). All cases had same characteristic of grids which are cubes with 1.0 m of all sides. As an initial condition, wind flows 5 m/s from left to right and a pressure gradient of 0.004 Pa/m were assigned to keep the speed of the wind. Boundary conditions were periodic boundary conditions in both x and y directions. In z-direction, the condition of the bottom was set as a no-slip condition while on the upper part was set as slip condition. This study divided the cases into 2 assessment groups with potential temperature as the main parameter; i) comparisons between normal building and Green Rooftop. ii) The comparisons between Green Rooftop and Green Floor. Almost all cases of Green Rooftop obtained the lowest result compared to the other potential temperature result. It explained that Green Rooftop indeed can have a good impact for the environment. But, among all of the 3 different types of the Green Rooftop with vegetation on the top of the building, case 2 had the lowest potential temperature (300.06°K). Height/Width (H/W) ratio of case 2 was 0.3 while the effective H/W ratio was around 0.4 - 0.6. It showed that case 2 is approaching the minimum limit on the effective H/W ratio. It had the best performance for potential temperature because of the balance condition between H/W ratio and solar radiation towards the area. © 2021 UTHM Publisher. All Rights Reserved.