Thermal Performance And Economic Analysis Of Large-Scale Dish Solar Thermal Power Generation System

The development and utilization of solar energy is of great significance to solve the global energy problem.Solar thermal power generation technology has proved to be able to replace the traditional power generation technology to some extent.In this paper,70kW large-scale dish solar thermal power generation system is the main research object,theoretical analysis and exploration are from the following aspects:(1)Monte Carlo method is applied for ray tracing and simulation,the flow density distribution and optical efficiency of the receiver cavity wall under different radiation conditions were obtained.By calculating the reflection loss rate,it can be concluded that the cylindrical receiver has less light loss and the receiver has better ability to capture light,the reflected light is not easy to escape.(2)The thermal flux density of the receiver cavity cavity is taken as the boundary condition,and the thermal performance of the cavity heat absorber is calculated and analyzed by CFD software.The results show that the solar radiation intensity has a great influence on the outlet temperature of the receiver,and the outlet temperature of the receiver increases with the increase of solar radiation intensity.With the increase of solar radiation intensity,the receiver heat loss increases,radiation loss increases the most,accounting for the proportion is getting higher and higher.When the radiation intensity is 200W/m2,the radiant heat loss accounts for 56.4%of the total heat loss,and when the radiation intensity is 800W/m2,the radiant heat loss accounts for 75.5%of the total heat loss.With the increase of solar radiation intensity,the receiver thermal efficiency is reduced due to the rapid increase of the heat loss of the receiver.When the radiation intensity of 800W/m2,the receiver thermal efficiency of 83%,200W/m2,the thermal efficiency of 85.3%.(3)According to the thermal characteristics of gas turbines,the outlet temperature of the receiver increases with the increase of the solar radiation intensity,the efficiency of the gas turbine increases,and the circulation efficiency of the thermal system increases.The intensity of solar radiation has a great influence on natural gas consumption.When the solar radiation intensity of 700W/m2 and above,fuel supplement is needed,pure solar energy will be able to run at full capacity.When the solar radiation intensity of 600W/m2,the thermal system is close to 90%load operation,when the solar radiation intensity of 400W/m2 or more,the system can run 70%load,no need to add natural gas.That is,in the clear day,the power station do not need to add natural gas for several hours.(4)Compared with the conventional coal-fired power plant dish solar power plant investment is still large,and the construction period is long.The average cost of energy is still high,with the average energy cost of LEC of 2.046 ?/kW·h,which main fuel is the solar power.So the current solar power plants still have to rely on government subsidies to achieve difficulty parity.Solar and natural gas combined power plant average cost of energy LEC is 0.74 ?/kW ·h,far below the cost of solar-based power generation mode.Therefore,ISCC system can be effective for reducing the cost and obtaining continuous and stable power supply.Through the sensitivity analysis,it can be seen that the power supply price of the power station and the basic investment of the power station have great influence on the economy of the power station,which is more than the economic impact of the natural gas price on the power station.Therefore,Reasonable on-grid tariffs have a significant impact on the profit and loss of power plants.