Performance of Hybrid Single Well Enhanced Geothermal System and Solar Energy for Buildings Heating

Abstract

The energy reserves in hot dry rock and hydrothermal systems are abundant in China, however, the developed resources are far below the potential estimates due to immature technology of enhanced geothermal system (EGS) and scattered resources of hydrothermal systems. To circumvent these problems and reduce the thermal resistance of rocks, here a shallow depth enhanced geothermal system (SDEGS) is proposed, which can be implemented by fracturing the hydrothermal system. We find that, the service life for SDEGS is 14 years with heat output of 4521.1 kW. To extend service life, the hybrid SDEGS and solar energy heating system is proposed with 10,000 m2 solar collectors installed to store heat into geothermal reservoir. The service life of the hybrid heating system is 35 years with geothermal heat output of 4653.78 kW. The novelty of the present work is that the hybrid heating system can solve the unstable and discontinuous problems of solar energy without building additional back-up sources or seasonal storage equipment, and the geothermal thermal output can be adjusted easily to meet the demand of building thermal loads varying with outside temperature.

Keywords

• single well enhanced geothermal system
• shallow depth enhanced geothermal system
• deep borehole heat exchanger
• hybrid geothermal and solar energy
• geothermal heating