Research On Modeling And Operational Characteristics Of Micro-grid Integrated With PV, Energy Storage And Ground-source Heat Pump

With the increasing problems of energy and environment, the use of renewable energy has become a central issue which the globe focuses on. Nowadays, the renewable energy sources that have been developed and utilized include solar energy, wind energy, tidal energy, biomass energy and geothermal energy. Photovoltaic generation has become the most promising distributed power generation since it has the higher rate of energy utilization in those utilization patterns. At the same time, ground source heat pump air-conditioning system makes full use of the shallow geothermal, so it has a good effect on energy-saving and emission-reduction. The micro-grid which is build on the distributed generation not only avoids the problem caused by accessing a large number of distributed generation into the grid, but also improves the reliability of electricity consumption. Based on that, the design of the combined use of solar electrical generation and ground source heat pump is proposed in this article, which can provide the building load with electric energy and hot and cold energy. In that way, electric energy can be saved and the pollution of air-conditioning system can be reduced, which comes up with a new idea for conservation and the rational utilization of energy.This article has built a micro-grid system simulation platform, in which PV battery simulation model that based on PQ control strategy, energy storage system simulation model that based on v/f control strategy and simulation model of ground source heat pump are orderly build. Based on the master-slave control strategy, the whole micro-grid system is simulated. The simulation result shows that the micro-grid system model with ground source heat pump which is made in this article has good economy on the premise of having certain commonality.In this article, the micro-grid system which contains solar photovoltaic, energy storage and ground source heat pump system is briefly introduced. The overall structure, operational principle and control strategy of this integrative micro-grid system is analysed. In addition, the operational process and the utility of it are emulated in TRNSYS.Based on the work above, the solar photovoltaic model, storage model and ground source heat pump model are respectively modeled in MATLAB. In this article, chapter three focuses on the research of photovoltaic energy storage model, v/f control model and their operational principle. Chapter four focuses on ground source heat pump model, including the evaporator model, compressor model, condenser model, expansion valve model, user terminal model and ground heat exchanger model, as well as its operational principle and process.Finally, in the simulation example part, the micro-grid system based on the master-slave control strategy which includes some building load is build in MATLAB. In this system, the solar photovoltaic and energy storage system provides the ground source heat pump and building load with power supply. The ground source heat pump provides buildings with hot and cold energy while gaining electric energy. The simulation result of this micro-grid system shows that the system with ground source heat pump not only has better effectiveness on energy saving than other ordinary micro-grid, and at the same time it reduces the pollution of air-conditioning system, and provides a new idea for conservation and rational utilization of energy.