Simplified Numerical Model for Analyzing the Effects of the Urban Heat Island upon Low-Rise Buildings by Using a Free-License Thermal Simulation Program

Abstract

In this document, the thermal effect of a heat island upon an urban area and its surrounding low-rise buildings is analyzed with the building thermal simulation program EnergyPlus and its EnergyPlus weather files (EPW). By using a top-down approach, a simplified numerical model is developed, which is used to simulate the urban heat island effect, and that deals with the performance of various cooling methods according to the physical, urban, and climatic characteristics of the urban site. The calculated results of outdoor air temperature considering the heat island effect achieve good agreement with the already-published results. Then, different methods of shading and cooling, varying physical values such as urban thermal transmittance, and urban thermal absorption are applied in order to find the most influencing feature upon the indoor temperature drop into a simulation loop. With this, it is found that a maximum average decrease of indoor temperature of 5.1 °C can be achieved. Furthermore, carrying out a sensitivity analysis, it is found that the albedo of both building surface and urban layout is the most influencing parameter onto the indoor thermal comfort. With this, it is expected to have a reliable model that helps to understand the urban heat island effect in a simple and cheap manner and in terms of the indoor thermal comfort of its surrounding buildings.