Coupling design analysis of geothermal cascade development and tail water waste heat recovery

Taking the geothermal well cascade utilization project on Yujiangdao, Hexi district, Tianjin as an example, this paper summarizes the prediction methods for water temperature and flow rate before the drilling of HX-54 and HX-54B twin wells. In phase 1 of the project, geothermal water is utilized to provide heat for the end radiator system. In phase 2, three design schemes are compared, namely the maximum waste heat utilization of HX-13 tail water, the maximum exploitation utilization of HX-54 geothermal water, and the different proportion reinjection of HX-13 tail water. The comprehensive cost, energy-saving effect, and overall benefits of these schemes are analysed, the relationship between the waste heat utilization amount of HX-13 tail water and the comprehensive cost is obtained, and the suggestions on how to promote tail water reinjection are provided, offering a comprehensive implementation route and a new thinking direction for the design and application of geothermal cascade utilization.