Development and operational optimization of a centralized-heating return-water-source heat pump for personalized heating system

Urban centralized heating systems operate at a large scale and exhibit strong thermal and operational inertia. Conventional peak shaving and operational optimization can partially alleviate terminal overheating and energy waste, yet they respond poorly to heterogeneous indoor heating demands, resulting in low indoor thermal satisfaction. To enable personalized temperature control without compromising the safety and stability of centralized heating, this study proposes a personalized heating system in which centralized heating satisfies the basic heating demand while a return water source heat pump provides secondary heating. Considering the constrained installation space and the adaptability, a compact evaporator based on a spiral coil configuration is developed. An experimental platform is established to quantify the responses of heating capacity, input power, and coefficient of performance to variations in return water conditions. The Simulink dynamic simulation under a typical heating season shows that system achieved an average coefficient of performance of 5.34, and the heat pump supplies about 27.4% of the cumulative heating demand, while the indoor temperature stably tracks the set-point with fluctuations controlled within 0.5 °C. Compared with the centralized-heating-only mode, the proposed scheme reduces the heating season operating cost by about 12.05% and lowers carbon emissions by about 18.81%. These findings demonstrate that adjustable user side supplementary heating based on return water waste heat can simultaneously ensure heating reliability, meet personalized demand, and deliver low carbon benefits with limited retrofit requirements, providing an engineering feasible pathway and quantitative basis for refined terminal control in northern centralized heating systems.