Geothermal and Solar Energy Combined Power Generation System—An Environment Friendly System Insubject to Geographic Location

The utilization of closed loop, which generates power by combining the geothermal system with solar energy system, is feasible to solve energetic problem and to exploit renewable energy. The power generation system can avoid such environmental problems as earthquake, heat pollution, ground sedimentation, decrease of geothermal water resources, toxicant pollution, caused by mass use of geothermal water resources. Moreover, the system is expected to be free of the limitation of the geographic location. The technology is to generate power by taking the advantage of the closed loop which combines the geothermal system with solar energy system. The geothermal system is suitable for ORC power generation since the vertical depth of the underground part is 3-5 km, horizontal distance is around 5-7 km, and the fluid temperature in the horizontal well comes to around 150 ℃. Trough paraboloid mirror is used in the solar energy system to collect heat in which either water or oil is feasible as heat collecting fluid, and it is possible for temperature to reach as high as or even higher than 350 ℃. Primary circulation media is water and the secondary one is isobutane. The maximal power generation productivity of ORC is 20% in the daytime and 12% at night. Chemical storage energy is adopted in the system which has a storage-density 10 times higher than the apparent-heat storage energy and the potential-heat one. The system is proved to be feasible after studying the relative technologies of drilling and completion, the transformation from solar energy to heat energy, heat-carrier fluid, ORC and storage energy.