Optimal Configuration And Comprehensive Evaluation Of Distributed Cchp System In Southern China

Southern China is suffering from the problems of great energy consumption and serious environmental pollution. Distributed Combined Cooling, heating and power (CCHP) technology has great significance in rational use of energy as well as energy-saving and emission-reducing for southern China. Based on the optimal configuration model, researches on the optimal configuration and comprehensive evaluation of distributed CCHP system based on small-turbine, micro-turbine and gas engine were carried out in the light of five kinds of southern typical buildings. The main works of this thesis are as follows:Firstly, the thermodynamic, economic and emission models were established for main devices of distributed CCHP system, including gas turbine, gas engine, absorption refrigerator, waste heat recovery boiler, gas-fired boiler, electric compression refrigerator and storage. And the comprehensive evaluation indices of system were given including economy, energy efficiency, environmental impact and peak shaving. The thermodynamic models are built in consideration of the influence of part load and output restrictions on main devices as well as ambient temperature on gas turbines, which lays a foundation for the accurate analysis and evaluation of distributed CCHP system.Secondly, based on superstructure modeling method, an optimal configuration model of distributed CCHP system was constructed which can achieve simultaneous optimization of system structure, discreteness of equipment numbers and capacities as well as operation rules. The problem that large-scale mixed integer nonlinear programming problem is difficult to solve is efficiently overcome through linearizing the nonlinear terms without any approximations. The optimal configuration model provides an effective means for the lectotype optimization and comprehensive evaluation of distributed CCHP system. Thirdly, according to the characteristics of climate and energy prices in southern China, optimal configuration and comprehensive evaluation of distributed CCHP system based on small-turbine, micro-turbine and gas engine were studied in five kinds of typical buildings including office building, market, residential area, hotel and hospital. The results show that, except residential area, the other four typical buildings, especially hotel and hospital, are suitable for the application of distributed CCHP technology; for the three kinds of prime movers, gas engine system has better economic performance than gas turbine system; two kinds of gas turbine systems have different features; the optimal capacities of small-turbines are between4and5MW.Finally, the influence of energy prices, grid interconnection with electricity selling and prime-mover cost on the optimal configuration and performance of system was investigated using single-factor sensitivity analysis method. Then the comprehensive influence of many uncertainty factors was studied using Monte Carlo simulation method. It is proved that, the most important factors for the economy of system are natural gas prices and electrical load; natural gas prices are extortionate in southern China, which acts as an obstacle to the development of distributed CCHP system; the policy of grid interconnection with electricity selling has a certain impact on the performance of system, but it is not the key-influencing factor; the payback period can be shortened as the prime-mover cost comes down.The datum, results and conclusions in this thesis can provide some references for the application and development of distributed CCHP technology in southern China.