Research And Analysis On The Application Of Distributed Renewable Energy System With Energy Storage In Residential Buildings

Due to technological advances and rapid population growth,the metropolitan cities are facing a massive increase in energy consumption.Distributed renewable energy systems are vital for satisfying the increasing demand for electricity in cities due to an influx of people.Nowadays,the residential buildings in metropolitan cities like Shanghai have natural height differences for potential energy,this advantage has not yet been fully exploited currently.To better utilize renewable energy,a grid-connected hybrid system with storage is first proposed for residential buildings,and an optimization algorithm is used for techno-economic optimization.Moreover,the operation principle of this system is developed,and two new concepts are introduced: the technical threshold constraint to start the pump and storage of water at night when there are off-peak hours.Under Shanghai’s time-of-use electricity price policy,the proposed methodology is applied in a case study to investigate the techno-economic feasibility of its application on residential buildings.The results demonstrate that the pumped hydro storage system on the apartment buildings can absorb more surplus power(4.83 k Wh/d)from the photovoltaic system than on the villa buildings,meanwhile,it can also release more power(3.69 k Wh/d)to meet the load demand.For residents of villa buildings and apartment buildings,the initial total investment is35,417 and 36,423 Chinese yuan,respectively,while the payback periods are 9.01 and 7.06 years respectively.The results also demonstrate that the photovoltaic capacity and load demand are the two key parameters affecting the cost and revenue of trading with the grid.The conclusion shows that the installed capacity suitable for residential buildings is: photovoltaic system is 5k W,battery is 1.45 k Wh,and upper reservoir is 73.86m~3.In addition,the meaning of threshold is to provide the judgment condition of the whereabouts(pump or battery)of surplus power for operation principle.Besides,the significance of water storage during off-peak hours is twofold: it has monetary benefits for residents and second,alleviate the grid pressure in terms of the peak-valley demand difference.It can be concluded that the cost of the system mounting the optimized installed capacity has dropped a lot,especially after the night-time water storage strategy is adopted,the payback period can also be shortened.Finally,wind-PV-battery-PHS system is proposed for villa building.The results show that only 35.1% of the electricity comes from the grid supply,and the dependence on the grid of users is reduced by 35.7%.In addition,the system self-sufficiency rate has increased significantly,from41.98% to 62.78%;and the payback period is 4.48 years.The amount of electricity saved by this system in one year is 4736.1 k Wh,which is 3834.6yuan,and the carbon emissions reduced is 3717.8 kg.In addition,a simple user operation software interface is designed through GUIDE of the MATLAB.The user can input the parameters into the software,and the result can be calculated and figures can be displayed directly in the program.In general,this research mainly takes large cities as the background to explore the application of renewable energy technologies based on energy storage in buildings.Through research and analysis,some instructive conclusions have been obtained.For example,small pumped storage systems can be applied on the buildings under grid-connected conditions,which can provide some theoretical guidance for residential users when choosing energy storage systems.In addition,the study of the starting power threshold of water pumps in this study can provide some references for future research and work: when facing multiple energy storage methods,it is necessary to consider which energy storage has priority.The environmental and economic benefits mentioned in the fifth chapter fully respond to the call of today’s society,and the calculated data can provide a theoretical numerical reference for the world’s environmental protection public welfare undertakings.