Design Parameters Optimization of MGT-ORC System based on Load Demand under Off-design Conditions

In order to improve the operation efficiency of the whole integrated energy system, this paper optimizes the cascade utilization of flue gas waste heat of the micro-gas turbine (MGT) unit. For fully utilizing the low-temperature flue gas discharge from MGT, the organic Rankine cycle (ORC) system is selected as the waste-heat generation unit. This paper optimized the ORC system parameters based on the actual load demand of off-design conditions, to obtain a more applicable result for practice. Based on the load demand over a period of time, a comprehensive index including system output power, thermal efficiency and output power per unit heat exchange area was established to balance the relationship between the efficiency and benefit. The ORC system was optimized by taking the evaporator pressure and the flow of working fluid as the decision variables while the operation condition of MGT as the interference variable. The optimization results show its advantage in off-design conditions, which is meaningful to practical engineering applications.