Investigation of thermal environment and the associated energy consumption of transportation buildings along the expressways in the cold region of China: A case study

•Thermal comfort of transportation buildings alongside the expressways was evaluated.•Energy consumption performance of these transportation buildings was studied.•The main influencing factors of energy consumption were analyzed.•Optimal energy system used in this kind of buildings was researched and analyzed. The transportation buildings alongside the expressways (TBE) have comprehensive characteristics, providing shopping and accommodations for drivers and passengers. However, the indoor thermal environment and energy consumption of such service buildings was not covered in most studies. To this end, based on some typical TBEs, this study investigated the thermal environment and energy consumption characteristics for TBEs. And the mentioned TBEs are located in Xiong'an New Area, a national special zone with requirements of low carbon and low energy consumption in China's cold region. The thermal environment study included questionnaire survey and on-site investigation by adopting dynamic thermal comfort evaluation index (i.e., Relative Warmth Index (RWI) and Heat Deficit Rate (HDR)). Then, the TBE energy consumption was investigated with the main influencing factor analyses. Finally, numerical simulations were conducted to analyze the energy efficiency approaches in TBE. The results showed that RWI and HDR were able to evaluate the thermal comfort of personnel in transitional environment of TBE in winter. Meanwhile, when the room temperature was set as 16 °C, it was still able to maintain the thermal environment for the indoor staff. The main energy influencing factors of TBEs are building scale, system equipment and usage characteristics. Besides, it was practicable to adopt the heat pump system to replace conventional space heating and cooling system, of which the total energy consumption of geothermal heat pump reduced by 38.1%.