Research On Distributed Energy Supply System With Complementary Biomass And Solar Energy

With the challenges of energy shortage,environmental pollution and climate change,it is necessary to improve energy consumption structure and increase energy saving and emission reduction.In the north,heating of scattered coal in winter is considered to be one of the main reasons of haze.Exploring clean and efficient heating technology has become a research subject.New ways of heating such as coal transformed to gas and coal transformed to electricity have been put forward,but the problems of cost and natural gas supply have not been solved yet.The distributed energy supply system can make full use of solar energy,wind energy,biomass energy,industrial waste heat and so on.Meanwhile,it provides users with cold,hot and electric load and has high energy efficiency.In order to make full use of the abundant solar and biomass energy resources in the rural areas and solve the heating problems in the northern countryside,the rural distributed energy supply system with complementary biomass and solar energy is studied,hoping to provide some ideas and references for solving the heating problems in the northern countryside.Taking the typical new rural buildings in Shijiazhuang as the object,the DeST software and the scenario analysis are used to calculate the hourly cooling,heat and electric loads in the whole year.The rural residents'building load fluctuates greatly,and the cooling and heat loads are far greater than the electric load,which is suitable for the distributed energy system.According to the load characteristic and the northern rural resource endowment,the rural biomass and distributed solar energy system is established.The following is how it works.The biomass enters the gas turbine after gasification,and the gas turbine drives the generator system in which extra electricity is used to transmit to the grid,flue gas enters into the lithium bromide absorption chiller heater cooling or heating,solar collector absor bs the solar radiation to produce hot water,and the heat pump is used as a standby,working when the distributed system can not meet the load demand.In order to make full use of loads,increase the stability of the system and reduce the capacity of the equipment,the accumulator is added in the system.A biomass gasification model is established,and theoretical gas components and gasification indexes under different gasification conditions are calculated.The changing trend of gas composition and gasification index to gasification agent equivalence ratio and moisture content is analyzed.A thermodynamic model of gas turbine,lithium bromide absorption chiller,energy storage device,solar collector and heat pump is established,and the off design characteristics of gas turbine and LiBr absorption chiller are analyzed.Based on the gasification model and the main equipment model and the off design performance,the performance simulation model of the whole working condition is established,and the hourly cooling,heating and electric balance is analyzed.According to the energy flow calculation model,the energy flow and energy loss distribution of the system are obtained.With the six indicators of primary energy utilization rate,energy saving ratio,CO₂ emissions,NO_X emissions,annual cost and investment payback period,the system energy efficiency,environmental and economic benefits are analyzed.Compared with the supply system,the distributed system of primary energy utilization occupies 53.58%,energy-saving occupies17.01%,CO₂ and NO_X emission reduction rates are 21.97%and 94.36%,the annual cost decreases 69.31%,the payback period is 11 years.It shows that the distributed system has advantages in the three aspects of energy,economy and environment.