Performance Analysis Of Hybrid Systems Based On The Concentrating Solar Power

Recently.the technologies of improving and controlling the power output of the renewable energy power plants have become the main research content.According to the references,the hybrid system based on the concentrating solar power(CSP)attracts attention due to its advantages including the increasing power output,sufficient utilization of the renewable energy,continuous power supply,flexible power output,and so on.A 10 MW concentrating photovoltaic/concentrating solar power(CPV/CSP)hybrid system and a large-scale PV-wind-CSP hybrid system are proposed to improve the reliability and performance of the hybrid system,and reduce the cost of the hybrid system.1.10 MW CPV/CSP hybrid systemFirstly,the coolant could absorb the heat dissipation from the solar cells and evaporat in the cooling subsystem,and the solar thermal receiver surrounding the solar cells absorbs the overfilling loss from the irregular facula to superheat the coolant vapor.As a result,the power output of the hybrid system increases.In a word,the integration of the CSP system could recover the heat dissipation from the solar cells and improve the hybrid system power output.Meanwhile,the operation of the hybrid system is presented.Secondly,proposing a steady-state physical model investigates the effects of the solar energy flux density distribution,average concentration ratio of the hybrid system,coolant output temperature from the solar thermal receiver,coolant saturation temperature in the cooling subsystem.Meanwhile,a gaussian distribution and a trapezoidal-shaped distribution of the solar energy flux density are employed.The results show that,the power output of the CPV/CSP hybrid system could increase by 25.01%compard with the alone-CPV system.When the average concentration ratio of the hybrid system increases,the trapezoidal-shaped distribution is beneficial to the performance of the hybrid system.Meanwhile,decreasing the coolant outlet temperature from the solar thermal receiver could improve the hybrid system power output with a maximum of 0.909 MWe.The power output could slight vary with the average concentration ratio and coolant saturation temperature.Finally,a dynamic physical model is proposed to analyze the effects of the solar radiation saltation or linear variation.The results show that the hybrid system could rapidly reach a steady state in less than about 53 s after the solar radiation saltation.The response time reflecting the thermal hysteresis of the hybrid system reduces with the decrease of the solar radiation linear variation gradient.Meanwhile,when the gradient is less than 0.2 W/(m2s),the parameters is approximately equal to the steady state values.As a result,using the quasi-steady state model could analyze the all-day dynamic performance of the hybrid system.The all-day dynamic performance shows that the power output and the flow rate are directly related to the directly normal irradiance(DNI),while the outlet temperature of R134a vapor is almost constant except for the starting and stopping periods.2.Large-scale off-grid PV-wind-CSP hybrid systemThe PV-wind-CSP hybrid system integrating an electric heating device is proposed to supply power for a local region.Utilizating the electric heating device recovers the power rejection from the PV and wind systems,and adding thermal energy storage(TES)controls the power output and match the flexible load demand.Firstly,establishing a dynamic physical model and an evaluation model analyzes the dynamic output characteristics to satisfy the load demand in Zhangbei area.Secondly,the dynamic performance of the hybrid system is analyzed on the typical days and during seven consecutive days around the spring equinox.The results show that the hybrid system can well match the load demand for most time,and recover the power rej ection when the hot tank is not full.Besides,the TES is conducive to the long-term heat storage.Next,the hybrid system is optimized based on the loss of power supply probability(LPSP),Levelized Cost of Energy(LCOE),and recovery ratio.The results show that,when increasing the LPSP,the LCOE of the hybrid system could reduce,and the hybrid system reliability also decreases.When the LPSP is fixed at 5%,selecting the appropriate solar multiple(SM)and TES capacity,a minimum LCOE of 0.2775$/kWh exists.Besides,the LCOE could also decrease by increasing the capacities of the PV and wind systems.Meanwhile,decreasing the SM and the capacities of the PV and wind systems or increasing the TES capacity are beneficial to reduce the recovery ratio,but the recovery ratio could increase by 6.36%with the increase of the TES capacity.Finally,to meet the power demand in Zhangbei area with the LPSP of 5%,the optimal configuration of the hybrid system is 900 MWe PV,3600 MWe wind,and 1360 MWe CSP system with the SM of 1.2 and the TES capacity of 190 GWht.The achieved values of the LCOE and the recovery ratio are 0.2775 $/kWh and 30.87%,respectively.