基于分时电价的热泵供热系统相变储热应用研究

Application of phase change heat storage in heat pump heating system based on time-of-use electricity pricing

中国提出“双碳”战略,推进可再生能源利用和供热电气化,降低电供热成本已成为迫切需求。本文提出了一种新型含相变储热的热泵供热系统。供热系统利用富余的可再生能源发电量或谷电储热,在可再生能源间歇期或峰电时段放热,实现热电解耦、削峰填谷,提高系统经济性。基于相变储热装置使用的灵活性,控制策略可根据可再生能源发电特性或分时电价时段动态调整。本研究测试以谷电为主要驱动能源的系统运行特性,分析不同储热时间和储热容量对系统经济性的影响,在青海高海拔地区进行供热实验。结果表明,含相变储热的热泵供热系统比热泵直接供热耗电量成本降低5.28%;储能容量为75 kWh时,通过调节控制策略改变储热时间可使系统能耗和运行成本分别降低5.69%、13.5%;增加储能容量至150 kWh可调节峰谷电用量,谷电占比最高可达84.52%,运行成本可再降低10.04%。含相变储热的热泵供热系统具有良好的经济效益,合理利用其热电解耦特性可助力可再生能源消纳和电网稳定运行。

China has proposed the goal of carbon peak and carbon neutrality to promote the utilization of renewable energy and electrification of heating.Reducing the costs of electric heating has become an urgent need.This study presents a novel heat pump heating system with phase change heat storage.The system charges during surplus renewable energy generation or off-peak electricity and discharges during intermittent periods of renewable energy or peak electricity,achieving thermoelectric decoupling and peak shaving.Owing to the flexibility in utilizing phase change heat storage devices,control strategies can be dynamically adjusted based on the characteristics of renewable energy generation or peak and off-peak electricity periods.This study analyzes the operational performance of the system primarily driven by off-peak electricity and examines the influences of different thermal storage times and capacities on the economy of the system.Experiments were conducted in the high-altitude region of Qinghai.The system with phase change heat storage reduces costs by 5.28%compared to heat pump direct heating.By adjusting control strategies to change the charging time with a storage capacity of 75 kWh,power consumption and operating costs of the system can be reduced by 5.69%and 13.5%,respectively.Increasing the storage capacity to 150 kWh can adjust the peak and off-peak electricity consumption,with the proportion of off-peak electricity reaching a maximum of 84.52%.This further reduces operating costs by 10.04%.The heating system with phase change heat storage demonstrates good economic benefits.The rational utilization of its thermoelectric decoupling characteristics can contribute to the absorption of renewable energy and the stable operation of the power grid.