Research On The Application Of Photovoltaic DC Microgrid In Nearly Zero Energy Building

Promoting the development of green building industry is an important step to achieve sustainable development of human society.In order to achieve the strategic goal of“emission peak and carbon neutrality”,the green building industry needs to vigorously promote nearly zero energy building technology.The application of photovoltaic power generation system and DC micro grid system can effectively reduce the level of building energy consumption,which is one of the important technologies to achieve nearly zero energy buildings.First of all,this paper conducts electrical design of a nearly zero energy building for a convenience service center,models in De ST-C,and analyzes the energy consumption demand of the building.By adopting high-performance building envelope,optimizing the windows to wall ratio,adopting efficient air conditioning equipment and other methods,the building energy consumption of the designed building is reduced from 115.56k Wh/(m~2·a)of the reference building to 82.78k Wh/(m~2·a)without setting a renewable energy utilization system,and the building energy efficiency improvement rate reaches 32.78%,meeting the requirement that the building energy efficiency improvement rate of the nearly zero energy public building in cold areas is not less than30%.Secondly,the photovoltaic array and photovoltaic controller of the photovoltaic power generation system are designed.Aiming at the problem that the incremental conductance algorithm(INC)of the photovoltaic controller is easy to fall into local extreme value when partially shading,and cannot effectively track the maximum power point of photovoltaic power generation,the special forces algorithm(SFA)with strong global search ability is combined with the particle swarm optimization(PSO)algorithm with excellent local development ability to propose an improved special forces algorithm,which is simulated in Matlab/Simulink,The effectiveness of the algorithm is verified under the conditions of uniform illumination,sudden illumination and partial shading.The PV power generation system designed in this paper is expected to generate46512.18 k Wh of electricity annually,with the utilization ratio of renewable energy for buildings of 69.44%and the building energy saving rate of 82.10%,meeting the requirements that the utilization ratio of renewable energy for nearly zero energy public building is not less than 10%and the building energy saving rate is not less than 60%.Finally,in the design of building power distribution systems,a comparison is made between the distribution links of AC and DC systems based on photovoltaic power generation systems,considering the DC characteristics of building power loads.When using a photovoltaic power generation DC distribution system,it can reduce the energy conversion process of electricity load distribution.On the premise that the air tightness of building envelope meets the requirements,by adopting high-performance building envelope,efficient air conditioning equipment,photovoltaic power generation system,optimizing the windows to wall ratio and other methods,the photovoltaic power generation DC micro grid designed in this paper can meet the energy criteria such as the building energy saving rate,building energy efficiency improvement rate,utilization ratio of renewable energy of nearly zero energy public building in cold areas,and achieve the nearly zero energy consumption design of the convenience service center,It provides an important reference for the promotion and application of nearly zero energy building technology,and helps to achieve the goal of“emission peak and carbon neutrality”.