Numerical analysis of three direct cooling systems using underground energy storage: A case study of Jinghai County, Tianjin, China

▸ We present three kinds of direct cooling system and establish numerical models. ▸ The characteristics of three systems is compared and analyzed. ▸ The double-wells circulating system remains long-term, safe and stable operation and is recommended as a prior way. ▸ The heat transfer effect of U-shaped tube system is relatively poor. ▸ The underground sink system is recommended as an auxiliary cooling system.