Comparative study on heat extraction performance between gravity heat pipe system and enhanced geothermal system

Gravity heat pipe system has been proposed as a new technology for deep geothermal utilization. However, its performance advantages in heat extraction performance are not fully understood. This study carries out a comparative analysis on heat extraction performance between gravity heat pipe system and enhanced geothermal system through building a 3D thermal-hydraulic coupled model. It is found that the two technologies increase heat extraction ratio and compensation ratio in smaller reservoir side. Gravity heat pipe system has higher effective heat extraction ratio and compensation ratio, while enhanced geothermal system has higher heat extraction rate, cumulative heat extraction, heat extraction ratio and cumulative compensation. •Heat extraction performance of EGS and gravity heat pipe system are compared.•Gravity heat pipe system has higher effective heat extraction and compensation ratio.•For small size fracture reservoir, gravity heat pipe system has good performance.•EGS shows longer lifetime and more heat extraction in larger size reservoir.