Metro systems play a crucial role in enhancing the urban economy, but the serious dust pollution during its construction poses a significant threat to the health of workers. Widely used for dust control in metro systems, the current forced ventilation technology is characterized by low dust control efficiency. In this study, an innovative arc device with efficient dust control and convenient application was proposed based on the forced ventilation. Subsequently, the orthogonal experimental method was adopted to explore the effects of air supply outlet position (L), air supply volume (Q), and air supply mode (M) on the airflow-dust distribution characteristics. The results indicated that compared with the traditional forced ventilation, the application of arc device can shorten the safe entry time after blasting operations by 9.9%–32.1% within the air supply volume of 804–1876 m³/min, effectively improving the construction efficiency and reducing the construction costs. In other words, the arc device can achieve the same dust control requirements with a smaller air supply volume, which improves the engineering applicability of forced ventilation in long-distance tunnel excavation while reducing ventilation energy consumption. Furthermore, the theoretical optimal combination scheme (L = 35 m, Q = 1876 m³/min, M = arc device) composed of the optimal levels of three factors achieved a 13% improvement in dust control compared to the experimental optimal combination scheme determined by the minimum safe entry time. This study can provide new strategies for improving the dust control performance of forced ventilation used in metro system construction.

By analyzing thermal adaptive behavior (TAB), we can access the occupant’s thermal comfort in real time and control the heating, ventilation, and air conditioning (HVAC) system accordingly to reduce energy consumption in buildings. Most existing methods are based on wearable devices or cameras to collect occupant behavioral information. Although these methods can effectively identify occupant behavior, they have the problem of violating user privacy. With the development of wireless technologies, human activity recognition using WiFi has the advantages of being non-invasive, privacy-friendly, and light-independent. Therefore, non-invasive TAB recognition based on WiFi technology holds great promise in human thermal comfort. However, existing research on TAB recognition based on WiFi technology lacks comprehensive and consistent conclusions. Thus, in this paper, we have surveyed the literature in recent years to guide in this area. In addition, we present the challenges and future perspectives faced by existing WiFi-based TAB technologies, e.g., developing high-quality WiFi sensing datasets to advance the field of human thermal comfort. We hope this review will guide researchers in recognizing the great promise of WiFi sensing applications for TAB recognition in smart buildings.

Covering the radiant cooling surface with infrared-transparent membrane effectively improves the condensation resistance and cooling capacity of radiant cooling. However, the air layer structure formed by the infrared-transparent and double-layer hollow membranes is easy to destroy, resulting in condensation problems. Inspired by the hollow structure of natural bamboo, an infrared-transparent bubble wrap assisted radiant cooling panel (BWRCP) aiming at improving the strength and cooling capacity was proposed by using the infrared-transparent bubble wrap consisting of infrared-transparent membrane and air-filled pores to layer the radiant cooling panel. Both experimental investigation and numerical calculation of the cooling capacity of the infrared-transparent bubble wrap assisted radiant cooling system were carried out. Experimental results showed that the cooling capacity of BWRCP at condensation-free condition was 93.54 W/m², which was 33% higher than traditional radiant cooling without covering infrared-transparent bubble wrap. Numerical results showed that the air-contact surface temperature of the infrared-transparent bubble wrap was higher than the dew point temperature. It provides condensation-free operation in the thermal environment of 26 ℃ and 45%–80% RH. Therefore, compared with traditional radiant cooling, BWRCP significantly improves the cooling capacity at condensation-free condition. It demonstrated a novel structure design and operation guidance for the high-performance radiant cooling technology.

Reflective and insulative composite coatings are a new energy-saving material with high solar reflectance and extremely low thermal conductivity for buildings. The optimization and impact of high solar reflectance and low thermal conductivity on the insulating capacity of walls remain uncertain. This work investigates the dynamic thermal performance and energy efficiency of a reflective and insulative composite coating in regions with hot summer and warm winter. A simplified thermal resistance-heat capacitance model of an exterior building wall is established to predict thermal performance. The dynamic temperature and heat flow of the wall are predicted to reduce heat loss through the interior surface of the wall and compared to the conventional coating. The specific impact of the thermal conductivity and solar reflectance of the coating on the heat loss is further investigated to minimize heat loss of the wall. This research shows that the composite coating shows better performance on adjusting outdoor climate change than the other coating. Compared with cement, it reduces the maximum temperature of the exterior surface of the wall by 7.45 ℃, and the heat loss through the interior surface of the wall by 38%. The heat loss is reduced with the increase of solar reflectance and the reduction of thermal conductivity. The results can provide a useful reference and guidance for the application of reflective and insulative composite coating on building exterior wall to promote their energy-saving use on building envelopes.