| The traditional energy supply mode of remote rural building in northwest China pollutes the environment,and seeking clean energy supply mode is an effective way to reduce the building energy consumption and improve the living quality.Renewable energy sources such as solar energy and air heat energy are extremely abundant in northwest China,and the multi-energy complementary system can be established to meet the energy demand of rural buildings in northwest China.Because of the intermittence and fluctuation of renewable energy,and it is difficult to match supply with demand.The integration of energy storage equipment is an important technology to balance the supply and demand of renewable energy system at present,but only relying on the regulation of energy storage will greatly increase the system cost.The flexible load has the characteristics of flexible scheduling,which can alleviate the contradiction between supply and demand,improve the efficient energy use and so on.Therefore,this paper puts forward the modeling method of multi-energy complementary building based on flexible load,and analyzes the influence of flexible load on the economy of multi-energy complementary building energy system,the specific work is as follow:Firstly,according to the energy situation in the rural areas of northwest China,a multi-energy complementarity system was established with consisting of photovoltaics batteries,solar collectors,air source heat pump and so on,and the system simulation model is established in Matlab/Simulink.Secondly,the typical building forms and the characteristics of flexible electric load equipment in northwest rural area are obtained through the investigation.Based on the flexible electric load and flexible thermal load regulation principle,the flexible electric load and flexible thermal load models are established respectively.Thirdly,taking the annual cost as the economic evaluation index of the multi-energy complementary building energy system,considering the flexible load participating,a capacity matching and operation scheduling simultaneous optimization model of multi-complementary building energy system is established.The joint optimization framework of Matlab and Simulink is established,and Genetic Algorithm is used to solve the problem.Finally,the effects of flexible load on annual cost under different climate conditions and thickness of external thermal insulation materials in northwest China is analyzed.For each condition,four optimization scenarios are set respectively,without flexible load,flexible electrical load,flexible thermal load,and flexible electrical/thermal load to regulate,and comparative analysis of flexible load regulation on the economy of multi-energy complementary system.The main conclusion of this study are as follows:(1)Taking Yulin area as an example,this paper analyzes the influence of flexible load on the operation characteristics and economy of multi-energy complementary system,and the optimization results show that:(1)After the flexible electric load,the flexible thermal load and the flexible electric/thermal load are adjusted,the annual cost of the system is reduced by 0.75%,0.99% and 1.29% respectively,and the annual cost of the system is lowest when the flexible electric load and flexible thermal load are adjusted simultaneously.(2)After the flexible electrical load is adjusted,the flexible electric load is transferred to the time of photovoltaic output,and the storage battery capacity can be reduced by consuming the photovoltaic output in time.After the flexible thermal load is adjusted,the indoor design temperature rises at noon,and the heat storage of the building reduces the heat supply of the building during the following period.(2)The cities of Jiuquan,Xining,Kashgar,Urumqi,Yulin,and Xi’an are selected to represent the six regions of the northwest region.After the flexible electrical load and flexible thermal load are adjusted simultaneously,the annual cost of the above six regions decreased by 0.34%,0.57%,0.18%,0.37%,0.43% and 1.29% respectively.Because most of the existing rural building wall in northwest China without insulation materials,and the flexible electrical load of a single building is small,so the effect of flexible electrical load and flexible thermal load regulation is not significant.(3)Taking the annual cost of system as the optimization objective,the sensitivity of multi-energy complementary building energy system is carried out.In the sensitivity analysis of the thickness of external thermal insulation materials,the annual cost of system can be reduced by 2.69% when flexible electrical load and flexible thermal load are adjusted simultaneously.In the sensitivity analysis of the unit price of photovoltaic cells,the annual cost of system can be reduced by 3.07% when flexible electrical load and flexible thermal load are adjusted simultaneously.In the sensitivity analysis of the unit price of storage battery,the annual cost of system can be reduced by 1.42% when flexible electrical load and flexible thermal load are adjusted simultaneously.The actual model of multi-energy complementary system is complex,there are a large number of nonlinear models,and considering the flexible load participating in the regulation of the multi-energy complementary system,so there are many optimization variables.Therefore,the commonly used traversal algorithm and mixed integer linear programming method can not solve this problem.Based on this,this paper sets up a capacity matching and operation simultaneous optimization model of Matlab and Simulink,which provides reference for solving this kind of capacity matching and operation simultaneous optimization problem.At the same time,this paper analyzes the influence of the northwest rural climate,the thickness of building wall thermal insulation materials,the unit price of photovoltaic cells and storage cells on the flexible load adjustment effect,it provides a practical guidance for the applicability of flexible load regulation in northwest rural area. |
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