Coordinated Optimal Scheduling of a Ground-Source Heat Pump-Based Hybrid Heating System in a Zero-Carbon Park Under Time-of-Use Tariffs

This study is based solely on simulations and develops a mixed-integer linear programming (MILP) approach for the coordinated scheduling of a ground-source heat pump, an electric heater, and a thermal storage tank serving office building clusters within a zero-carbon park in a severe cold region under variable heating loads and time-of-use electricity tariffs. Heat source outputs and tank charging and discharging schedules are jointly optimized to minimize operating costs while satisfying hourly heating demand and equipment operating constraints. A case study of office buildings in Daqing compares a baseline strategy without thermal storage, a fixed-window optimization strategy, and a coordinated optimization strategy. Compared with the baseline, coordinated optimization reduces operating costs by 9.22% on the typical day and 12.88% on the extremely cold day. Over the heating season, operating costs decrease from CNY 7.7623 million to CNY 6.9855 million, representing a reduction of 10.01%. Peak-period electricity purchases decrease by 45.83%, whereas total electricity purchases increase by 5.00%. These results indicate that the economic benefits arise primarily from improved electricity-use timing and heat source dispatch, rather than reduced electricity consumption. Sensitivity analysis reveals diminishing returns from increasing tank volume, while the effects of the peak-to-valley electricity price ratio and heat pump charging efficiency on cost savings depend on operating conditions. The findings provide guidance for the cost-effective operation of low-temperature heating systems serving office building clusters in severe cold regions.