The Research Of Distributed Energy Resources System

Energy is used to maintain the survival of human activities.With the socio-economic development,there is growing demand for energy.At present,coal is the main energy in the constitution of energy consumption in our country.Because of irrational energy structure and lowly energy efficiency,China is one of the highest energy consumption countries,and carbon dioxide emission intensity is relatively high,we should construct the development model,which should be sustainable and in harmony with nature,for example, developing integrated multi-energy system and utilizing renewable energy resources.Based on Natural Science Foundation Project "The devices and applications of CCHP system (NO 50746001)"," The algebra explicit analytical solutions of Thermo-mechanical engineering problems(NO 50876106)",etc.,Distributed energy resources systems was researched and summarized by stage.The main contents of this paper contain integrated solar energy with CCHP system and typical off-design performance of piston-type internal combustion engine(simply,internal combustion engine) CCHP system,as well as the impacts of environment parameters on CCHP system.Solar energy,as one of renewable energy,is the most impressive clean energy.With low energy density,discontinuous,unstable,and vulnerably affected by changing environment parameters and so on,solar energy should complement other energy. Distributed resources energy system,on the one hand,as a small-scale model system,is suitable for combining with solar energy;on the other hand,it makes up shortcomings of solar energy such as incontinuous,instability.For these reasons,a novel system which integrated solar energy with CCHP system was proposed.Based on classical fuel energy saving ratio,an annual fuel energy saving ratio was raised,which is more suitable for evaluating the new system,and adopted in this paper to determine the optimum area of solar collector and compare with the performance of traditional system.With different power capacity,the optimum area of solar collector was different and investigated.With the same installation capacity,solar radiation intensity and sunshine duration,the influenced on the design of the optimum area of solar collector and system,were analyzed. The research of internal combustion engine CCHP system off-design performance is still at early stage,starting from the off-design performance of internal combustion engine, heat recovery steam generator(HRSG) and absorption refrigeration unit,based on the off-design analysis formula of the constant speed internal combustion engines and analysis off-design performances of HRSG,combined with modified DOE-2 model of Lithium bromide absorption refrigeration unit,the off-design performance of cogeneration system had been investigated.Considering the influences of the internal combustion engine part-load,cooling water inlet temperature and chilled water outlet temperature on system, with decreasing of the internal combustion engine load,total energy efficiencyZ,equivalent exergy efficiencyη_ex,economic exergy efficiencyθand fuel energy saving-ratio FESR increased first and then decreased,they existed maximal value when relative power(?) equaled to 0.8,it was the best point for the system.When(?) was about 0.2～0.3, the FESR was negative,compared to sub-production system,CCHP was not energy-saving.Environmental parameters have great impacts on the off-design performance of CCHP system.The analysis of the gas turbine CCHP system was only qualitative;the influence of atmospheric pressure on the internal combustion engine CCHP system had focused on. With the decreasing of atmospheric pressure,η_ex,θand FESR increased first and then decreased,it existed maimal value when atmospheric pressure was about 0.8bar,but Z always decreased.