UC Davis

In the context of urban microclimates, thermal comfort serves as the key indicator to describe people's subjective impression of temperature in open spaces. It gives a general review of how the sun, wind, air temperature, and humidity affect the ability to perceive heat. But nowadays human thermal comfort is being compromised due to the urban heat island effect. The phenomenon known as the urban heat island (UHI) occurs when the temperature in metropolitan regions is higher than in the nearby rural areas. Urban heat islands are a source of growing concern since they can have an impact on communities by worsening air pollution and greenhouse gas emissions (due to increased air conditioner use), increasing the likelihood of heat-related disease, and possibly even raising mortality rates. For this purpose, evaluating the human thermal comfort level would be a significant step in adapting feasible solutions to reduce the adverse effect of the urban heat island. The goal of this study is to simulate the microclimate using the ENVImet (V4) computer and the RayMan model to increase albedo, or the ratio of reflected incoming radiation, for the human thermal comfort index. The ENVImet (V4) software is validated using air temperature and solar radiation data gathered in several USA locations. The microclimate simulator ENVImet can be used to determine the high-resolution geographical and temporal distribution of microclimate variables within an urban region .The RayMan model was created for the physiological equivalent temperature measurement and the estimation of the mean radiation temperature along with thermal indices in simple and complex situations .

Historical information about places with changeable seasonal circumstances was used for simulation and analysis after the necessary inputs and limits for the models are determined. The results of the simulation was used to assess the level of thermal comfort for both adults and children and recommendations would be provided to improve human thermal comfort.

The study conducted on microclimate simulation of four scenarios of asphalt and concrete pavement using Envimet and optimization with Rayman has led to the conclusion that an optimal albedo value of 0.15 is ideal. Although the study was conducted based on data from two months, June and July, further research can improve the accuracy of the findings. The results of this study are valuable as they provide insights into the effects of different pavement types on the microclimate and can help in the design and planning of sustainable urban environments. It is essential to consider the impact of pavements on the microclimate and the resulting effects on the urban ecosystem, especially in the context of global warming and climate change.