Performance analysis of seasonal thermal energy storage system with urban reclaimed water waste heat for low-carbon heating

In order to promote the application of seasonal thermal energy storage technology in cold regions to realize low-carbon and clean heating in northern China, a seasonal thermal energy storage system with urban reclaimed water waste heat was proposed. The long-term operation characteristics of the system were studied through numerical simulation based on TRNSYS. The volume of heat storage unit and the flow of reclaimed water in the system were optimized considering the heating demand and operation cost, and the feasibility of the system was demonstrated from the perspective of environment and economy. The results show that the system can be applied to district heating efficiently and stably. The soil temperature rises by 2.84 ℃ after 10 a of continuous operation, and the coefficient of performance of the heat pump is 2.80%−18.22% higher than that of the traditional ground source heat pump system. Increasing the volume of heat storage unit is conducive to improving the storage efficiency and maximum heating capacity of the system. Selecting a large volume of heat storage unit and a small flow of reclaimed water can achieve better economic benefits with the same heating capacity. The carbon emission of the system is close to that of the solar seasonal thermal energy storage system, it can reduce by 59.10% compared with the traditional heating system, and the annual heating cost can reduce by 36.51% and 24.64% respectively compared with the solar system and the traditional heating system. © 2023 Central South University of Technology. All rights reserved.