## 1 Introduction  
Building energy consumption accounts for almost 1/3 of the total energy consumption for heating in winter and cooling in summer, leading to excessive use of fossil fuels and severe environmental pollution [1]. As a clean and renewable energy source, solar energy has been utilized in building air conditioning and refrigeration systems to alleviate energy and environmental problems. The Trombe wall (T-wall) system is one of the most effective passive solar energy utilization technology systems. It relies solely on passive solar energy collection to provide energy for buildings' heating, cooling, and ventilation. This system can reduce the energy consumption of traditional buildings while improving indoor thermal comfort. The first T-wall, installed by architect [PERSON] in Odeillo, France, in 1967, was named after engineer [PERSON]. In the last half-century, many scholars have conducted theoretical and practical research on it. The T-wall system is popular due to its unique characteristics, which include environmental protection and energy-saving capacities, low maintenance requirements, a simple geometric layout, easy installation, and zero operating costs [2]. The classic T-wall consists of a glass panel, a cavity gap, and a thick heat storage wall with a black coating on the outer surface [3]. Vents are placed at the top and bottom of the thick wall, connecting the indoor environment to the T-wall cavity gap [3]. As shown in Figure 1, solar radiant heat heats the air in the cavity gap between the glass panel and the heat storage wall, and the uneven rise of air temperature leads to a density change in the upper and lower parts, which makes natural convection movement under the action of buoyancy [4]. During the day in winter, cold air enters the cavity gap from the bottom vent and returns from the top vent after being heated, which gradually increases the indoor temperature, and the thermal convection cycle finally reaches a stable state at a specific moment. At night, the heat storage wall slowly releases the heat stored during the day through natural convection and heat conduction [5]. The improvement effect of the T-wall on the indoor environment has been confirmed in many previous studies. [PERSON] et al. [6] found that even when solar radiation was low, the T-wall structure could still achieve ventilation in summer and heating in winter. The studies of [PERSON] et al. [7] and [PERSON] et al. [8] showed that a T-wall could raise the room's temperature and keep the room comfortable in a cold climate. [PERSON] et al. [9] found that T-walls can effectively enhance the natural ventilation of two-story buildings to reduce the indoor temperature and thus improve thermal comfort. In addition to the functions of heating, cooling, and ventilation, other emerging functions of T-walls are also gradually being explored. [PERSON] et al. [10; 11; 12; 13; 14; 15] conducted a large number of studies on T-walls based on the geographical and climatic conditions in Hefei in recent years; three new types of hybrid T-wall, based on classic T-walls, were proposed, including photocatalytic (PV) Trombe walls, thermal catalytic (TC) Trombe walls, and photocatalytic and thermal catalytic (PV-TC) Trombe walls. These composite walls can be used for space heating, air purification and sterilization, and energy saving. Since a T-wall is a passive technology, its contribution to reducing energy consumption is also a research focus. [PERSON] et al. [16] found that applying this indirect passive solar energy gain system has a significant energy-saving effect, and will bring tremendous energy and economic benefits to Turkey. Using a TRNSYS simulation, [PERSON] et al. [17] found that a T-wall could save 3312 kW\(\cdot\)h of energy and reduce emissions by about 33 tons of CO\({}_{2}\) every year. [PERSON] et al. [18] studied the performance of several T-wall structures in Lyon, France, and found that buildings using T-walls ultimately saved about 20% of the energy used in the heating process each year.