Optimal Operating Strategy Of Community Integrated Energy System Considering Seasonal Balance Of Ground Source Heat Pump

With widely integration of renewable energy,challenges have been put forward for the actual operation of energy systems,such as the coordination and conversion of diverse energy sources.Community integrated energy system(CIES)is regarded as a potential solution to the challenges,which will plan,operate and manage different energy subsystems under a unified framework.As an important part of CIES,ground source heat pump(GSHP)has been now widely used because of its high efficiency in energy conversion.However,the coefficient of performance(COP)of GSHP will be unstable if the soil temperature changes with the seasonal imbalanced cooling and heating loads,and the overall performance of CIES will be downgraded.Therefore,an optimal strategy for CIES operation is proposed in this thesis to realize the seasonal balance of GSHP while ensuring the stable,economic,and sustainable operation of CIES.The main contributions of this thesis are summarized as follows:1)According to the structure of CIES and operation principles of related equipment,the models of multiple subsystems including photovoltaic,GSHPs,cold/hot water tanks,double-duty chillers(DCs),conventional water-cooled chillers(CWCs),ice-storage tank(IT),electric boilers(EBs)and various auxiliary equipment are built.2)A year-round optimal scheduling model for CIES considering the seasonal balance of GSHP is established.The GSHP works in seasonal intermittent operation and short-term intermittent operation mode,and cooperates with a variety of energy supply and energy storage equipment in the CIES.By optimizing the allocation of cooling and heating loads among GSHP and other equipment,an optimal operation plan can be obtained.The scheduling scheme can guarantee the balance of the total cooling and heating supply of the GSHP throughout the year,and realize long-term stable operation.3)Control variables are introduced to build a CIES day-ahead optimal scheduling strategy considering daily uncertainties in load demands and environmental conditions.To lower the effect of uncertainties from renewable energy generation and loads in daily operation,the scheduling scheme based on pre-allocated working plan is adjusted according to the day-ahead forecasting deviation of environmental factors and load demands.By introducing uncertainty constraints,the daily operation plan will be adjusted based on the forecasted load and DG generation to obtain a flexible and reasonable day-ahead scheduling scheme on the premise of ensuring the seasonal balance.