Research on Temperature Measurement Requirements for Seasonal Thermal Energy Storage Water Pits

Solar seasonal thermal energy storage technology is an important means to solve the problem of seasonal uneven distribution of solar resources, and as the core component, the thermal storage capacity of the water pit directly affects the performance of the whole system. Accurately mastering the water pit temperature is essential for scientifically evaluating its thermal storage capacity. Based on the thermal storage water pit simulation software developed in the laboratory, this study focuses on determining the optimal number of temperature measurement points required for seasonal thermal energy storage water pits under an accuracy requirement of ±0.1°C, and establishes the mathematical relationship between the number of measurement points and the height-diameter ratio (H/D) as well as the inlet position. The proposed method can cover the temperature measurement point design for cylindrical and frustum-shaped water pits, and can also be referenced for prism-shaped configurations. Combined with the thermal performance analysis of the Huangdi City Phase II seasonal thermal energy storage project, the applicability of the mathematical relationship has been verified. The optimal number of measurement points obtained in this study provides effective suggestions for the scientific design of water pit temperature measurement systems.