Application Of Microgrid System In Low Energy Consumption Buildings

With the promotion of building energy conservation policies,green buildings and near-zero-energy buildings will gradually become the main form of future construction.Building energy supply needs diversification,intelligence,and green energy supply methods.Integration of buildings and microgrids is a kind of Feasible design.Low-energy buildings use less electricity,and their power supply modes need to be lower and lower in carbon,environmental protection,and high-efficiency,and the low-energy buildings' development to zero-energy buildings also shows a trend in building their own production capacity.The design and construction of microgrid based on the demand of low-energy-consumption buildings is more efficient than conventional mains and renewable energy,which improves the safety of power supply,reduces the loss of energy storage and increases the proportion of renewable energy.In this paper,a set of low voltage and off net micro grid system for low energy office buildings is designed.The system is built on the basis of the power consumption of the actual single building and the power consumption habits of the building.On the basis of the simulation of building energy consumption,a linear programming method is used to set up the system.The external environment constraints and user requirements constraints are transformed into quantitative equations by mathematical methods,and the best user allocation scheme is obtained through calculation.The experimental platform is set up to verify the technical feasibility.The experimental platform integrates the output conversion of renewable energy,DC unit and AC unit,and completes the parallel energy supply of unstable renewable energy,stable DC power supply and stable AC power supply in the island system,and realizes the joint operation of three types of power generation devices.The system outputs the power quality to meet the user's demand.A market user survey was conducted on the basic models of micro grids operated jointly by photovoltaics,fuel cells,and micro turbines.Potential users were divided into three categories according to their needs.Each group of users was judged by the analytic hierarchy process on its acceptance of the micro grid system in this design.In terms of degree,the results of the analysis show that potential users' demands for microgrids have economic and environmental benefits,and those with higher requirements for environmental benefits have a better solution for environmental benefits with a weight of 0.53;The economical option with a good option is 0.69;two users who both require the choice of a better economical microgrid plan,with weights of 0.53 and 0.39,respectively.After the design experiment was completed,the system was economically analyzed.The power cost of the microgrid system was 1.6 yuan/kWh,and the net present value in the life cycle was 635,000 yuan.Through sensitivity analysis,the main factor affecting the system power cost is the running time,and its sensitivity coefficient is 0.65.Through the design,experiment and application analysis of the isolated island microgrid system,it is proved that the system is stable and feasible,and the power quality meets the requirements of the relevant national standards.The power cost of the system reaches 1.6 yuan /kWh,and its application potential is still high under the condition of high cost.At the same time,the system design method,economy and user evaluation method used in this paper can be used as an effective method of life cycle design evaluation for microgrid system.