Effect of urban microclimates on dynamic thermal characteristics of a vehicle cabin

Abstract

The external climate consistently maintains thermal transfer with the vehicle cabin. The complexity and variability of the urban microclimate cause dynamic changes in the thermal characteristics of the cabin. Combining the differences in spatial structure and environmental characteristics of urban roads, this study proposed a cabin thermal management method based on matching cooling schemes for different urban microclimates in road space, aiming to achieve thermal comfort and low energy consumption. Environmental load spectrum tests were conducted in three types of urban road spaces during the summer in southern China, including open roads, boulevards, and underground parking lots. The primary environmental loads experienced by the vehicle in service are solar radiation, high temperature, and high humidity. However, these loads vary significantly due to factors such as cloud cover, building and tree shading, and tree transpiration. Combined with the cabin thermal model, the study analyzed the effect of environmental differences in road scenes on the dynamic thermal characteristics of the vehicle cabin, and explored the variability of passengers’ cooling requirements. The results indicated that the HVAC air supply temperatures of 10.5°C, 15.8°C and 20.5°C should be respectively adopted on the open road, boulevard and in the underground parking lot.

Keywords

• Vehicle thermal environment
• Urban microclimate
• Thermal comfort of passengers
• Transient thermal model
• Thermal management in cabin