Optimization Of Distributed Multi-energy Complementary Energy System For Low-carbon Community

Distributed multi-energy complementary energy system plays a role of energy hub that integrates multiple energy technologies,and it can meet the thermal load demand of community by utilizing the renewable energy and conventional energy.Distributed multi-energy complementary energy system is important for realizing the low-carbonization of the community.This paper studies the optimization method of the equipment configuration and the operation strategy to make the full use of the system superiority,such as high rate of renewable energy utilization,high efficiency of conventional energy utilization and flexible operation control.Firstly,eQUEST is used to study the load characteristics of typical monolithic buildings of a community in Beijing.Based on the load characteristics of monolithic buildings,the overlapping and complementary characteristics of thermal load among various buildings are further analyzed,and the load characteristics of the community can be achieved.Secondly,based on the dynamic load characteristics of community and the construction principle of community energy system,the distributed multi-energy complementary energy system is comprised of photovoltaic,solar thermal utilization,air source heat pump and energy storage.The mathematical model of the system is established to clarify the energy conversion characteristics of each essential equipment and the mechanism of cooperative energy supply among the equipment.Based on the mathematical model of the system,the two-layer optimization model can be further established,and the equipment configuration and operation strategy of the system can be optimized under the condition of meeting the thermal load demand of the community.The establishment and calculation of the system mathematical model and the two-layer optimization model are realized by TRNSYS and programming.Finally,a community in Beijing is taken as the study case.The optimal design configuration and operation strategy of the energy system are analyzed from the angle of the community level and building level.The results show that the optimization model is suitable for the distributed multi-energy complementary energy system at the community level and building level.The optimized community-level energy system can mitigate CO₂emission to 38 kg/（m²·a）,which meet the standard of low-carbon community.Furthermore,compared with the conventional sub-supply system which is comprised of electric refrigeration units,gas boilers and municipal power grid,the community-level optimization system can mitigate annual cost and annual CO₂emissions by 28%and 32%,respectively.While the building-level optimization system can mitigate annual cost and annual CO₂ emissions by 21%and 24%,respectively.The results prove that the economic and environmental performance of the community-level optimization system is better than that of the building-level optimization system.The distributed multi-energy complementary energy system should be set up for the whole community to maximize the benefits of the system.