Numerical modeling and optimizing of geothermal CCHP integrated energy system in Xiaoreshui, Kangding county in Sichuan Ganzi Prefecture.

Abstract

This study presents a numerical modeling of geothermal CCHP integrated system. To improve efficiency of energy utilization, an integrated system with Organic Rankine Cycle (ORC) is designed for generating electricity and providing heating in winter. The ORC unit is the core part the integrated energy system.
An ORC numerical model is established to optimize the design of the power generation system. Key parameters of the system, including the type of working fluid, evaporation pressure, condensation pressure and pinch point temperature difference, are optimized in the numerical model. The return flow from the ORC plant is used as a heat source for a district heating network.
For the effective utilization of geothermal resource, aquifer energy storage unit is applied in the system to store the return flow from the plant during summer, so that the injected water can be extracted during the heating season. The economy is the objective function of this cogeneration of power, heating and cooling system optimization.
The most economic feasible design of the system is achieved through optimization.