Research On Energy Storage Strategy And Operation Scheme Of Rural Household Photovoltaic System

With the implementation of the"double carbon"action plan and the promotion of the"county development pilot"work,distributed photovoltaic has taken root in thousands of towns and villages in China,with rapid expansion of installed capacity,continuous improvement of green electricity supply capacity,rapid growth of photovoltaic installed capacity,and year-on-year expansion of grid connection scale,which also makes the local consumption of clean electric energy face greater pressure.With the promotion of rural electrification,the proportion of rural electric energy consumption increases.If the installed household photovoltaic can be fully utilized,the pressure of electricity consumption can be effectively alleviated,the rural energy transformation can be promoted,and the quality of life of rural residents can be improved.A photovoltaic energy storage system for rural households is proposed considering the current situation of household photovoltaic energy utilization and the future energy demand of the region.The system includes photovoltaic power generation system,air source heat pump system,indoor heating and cooling terminal system,solar collector,heat storage tank,household appliances,etc.The indoor temperature can be adjusted by controlling the running time of the air source heat pump to meet the comfort demand.Increase the storage water tank and some household appliances to store electric energy,realize the direct absorption of photovoltaic power generation,peak reduction and valley filling,improve the utilization rate of green energy.First of all,two field surveys were carried out on rural rooftop photovoltaic installation and household heating and cooling methods.The results showed that the scale of distributed photovoltaic installation in rural areas increased year by year,and the grid-connected mode of full access to the Internet was relatively common.In summer,air conditioning is used for cooling,and regional differences in winter heating methods are obvious.The overall trend of energy utilization is closer to comprehensive electrification.Secondly,based on rural heating and cooling demand,the establishment of household photovoltaic energy storage system.Make clear the operating conditions of the system in winter,summer and transition season,and the composition of the internal photovoltaic power generation system,household appliances,air source heat pump,indoor heating and cooling terminal system,energy storage equipment and control system.Using TRNSYS software to simulate the annual cooling and heating of a rural residence with installed photovoltaic capacity of 27.2k Wp,the building area is109.6m~2and actual cooling and heating area is 90m~2.According to photovoltaic output,air source heat pump operation and time-shared peak and valley electricity price at the project site,the initial operation strategy of air source heat pump in heating season and cooling season is determined from 5:00 to 17:00.Optimize and adjust the operation strategy from the typical day,typical month,the whole cooling(warm)season load side water temperature and power consumption.A rural residential building in Tengzhou,which has been installed in the survey with a capacity of 27.2k Wp,a building area of 109.6m2 and an actual cooling and heating area of 90m2,is selected as the building model.With indoor temperature of 18℃and relative humidity of 50%in winter and 26℃and relative humidity of 55%in summer as indoor parameters,De ST-h software was used to calculate the cumulative heat(cold)load from 17:00 to 5:00 in typical daily hours of the building,and the volume of the energy storage tank was determined to be 4.6m3.What calculation is used to calculate the building heat load is 7676.62W,cooling load is7390.64W.Based on this,determine the device model in the system.According to photovoltaic output,air source heat pump operation and time-shared peak-valley electricity price of the project site,the initial operation scheme is set as the air source heat pump operation from 5:00 to 17:00,and the energy storage tank operation from 17:00 to 5:00.When the air source heat pump unit is running,it starts to heat(cool)the hot(cold)water in the energy storage tank and provides heating(cooling)for the room.TRNSYS software was used to simulate the cooling and heating of the built system in winter and summer,and the hourly data of the operation was output.The operation time of the air source heat pump is adjusted from the analysis of the water supply temperature at the load side,the system electricity consumption and the electricity consumption period.By comparing the output results of 7 different operation schemes in winter and summer,the air source heat pump runs from 9:00 to 16:00 and 22:00 to 5:00 in winter,from 7:00 to 18:00 and 22:00 to 5:00 in summer.At the same time,based on the optimal operation scheme of the air source heat pump,the fully controllable load appliances in the household appliances of the system can be used from 10:00 to16:00,and the incomplete controllable appliances with energy storage performance can be used from 11:00 to 14:00 or the off-peak power at night(22:00 to 8:00),so that the clean energy can be used more efficiently and the load peak can be reduced.Fill load trough.Finally,the system benefit of the system is calculated and analyzed in detail,referring to the five common rural energy supply schemes in winter and summer(bulk coal,gas,mains,mains+photovoltaic electric energy,energy storage tank storage)in the investigation,the initial investment,operation cost,the total operation cost in 15 years,energy saving.According to the calculation results,the initial investment of photovoltaic energy storage system for rural households is the highest,which is 102,169 yuan.The optimized operation cost is the lowest,which is 15.53 yuan/m~2.Depending on the income from photovoltaic electricity sales,the photovoltaic energy storage system for rural households can recoup the investment cost in 9.6,and the annual energy supply is equivalent to 4.93kg·ce/m~2,which is the best energy saving.Considering the economic benefits,environmental benefits,social benefits and energy saving,the scheme of household photovoltaic+air source heat pump+energy storage tank has a strong promotion and application value in rural areas...