###### Abstract
After on-orbit verification, because each branch of the system has strong coupling characteristics, the current closed-loop control method based on flow and temperature is not suitable for a large number of parallel fluid systems. The thermal control system of the module experienced major parameter oscillation during the operation mode conversion, which was improved by updating the control algorithm on orbit [14]. Because the thermal control system in the rack is set to a fixed manual regulation mode, the regulation range between the loads in the rack is affected by the pressure difference outside the rack and the resistance characteristics of the regulation terminal; thus, it is impossible to realize on-orbit dynamic fine regulation between the loads in the rack [15; 16]. In the \"European Columbus\", a parallel single-phase fluid loop is used as a thermal management tool to regulate the total pressure of the system based on the frequency conversion of the pump [17], resulting in less independence of thermal control resource regulation between loads. If the pump speed is adjusted frequently, the robustness, stability and component reliability of the large-scale system will be reduced. Based on the experience of large-scale spacecraft thermal management systems, there are many problems in thermal control system principle construction and precise stability control. In the early 2000s, China began to build its own space station, with an unprecedented number of scientific experiments planned for rolling out implementation over the next 10 to 15 years [18]. Compared with the payload inside a conventional spacecraft, the heat sources in the modules of CSS represented by the scientific experiment racks are characterized by large scale, wide space layout, multi-level thermal control, diverse demand for temperature control, complex working mode and long life on orbit [19]. Problems such as maintenance, upgrade and extension and replacement of loads on orbit pose a great challenge to the thermal control of the whole module and the internal loads of the rack. The collection, transmission and dispersion of waste heat generated by the payloads in the space station module need to solve the overall configuration design of a complex large-scale thermal control system and establish and verify an efficient and stable control method. The traditional thermal control system and operation mechanism cannot satisfy the thermal control demand of the experimental lab module of CSS. A new, reliable and efficient integrated thermal management system for the space station experimental payload module is constructed to meet the new thermal control application objectives, scientific requirements and mission guidance. This paper focuses on the heat management problem of the payloads in China Space Station. The payload distribution characteristics, temperature control requirements and boundary constraints of CSS are analyzed in detail in Section 2. According to the requirements, a two-stage bus-type thermal control system based on single-phase fluid loop is constructed in Section 3. In Section 4, the General Control Method and theoretical model of the thermal control system are put forward, and the control characteristics of the system are analyzed with the working parameters of the pump valve. In Section 5, the system scheme and control method are verified on orbit for a special module of CSS, and the data analysis and evaluation of the fluid operation parameters, control characteristics and heat transfer characteristics of the thermal control system are carried out.