Techno-economic performance of air source heat pump and thermal energy storage considering peak-valley time-of-use electricity prices

With the continuous transformation of energy structure, air source heat pump (ASHP) has gained extensive applications in building energy efficiency fields due to their merits of high efficiency, energy-saving performance and environmental friendliness. Nevertheless, practical applications of conventional ASHP system are constrained by high capital investment costs, and integrated energy storage technology can effectively tackle this issue. By exploiting peak-valley electricity pricing and integrating off-peak thermal energy storage, peak load shifting is achieved, which maximally reduces building operational energy consumption and costs, and simultaneously mitigates carbon emissions. Taking a typical office building located in Tianjin as the research case, this study establishes the models of the air-source heat pump coupled energy storage system and the conventional ASHP system. A comprehensive comparative analysis is conducted from the perspectives of thermodynamic performance, economic efficiency and environmental benefits. The results reveal that in contrast to conventional ASHP system, the designed system can decrease initial investment by 29.7% and annual operating expenses by 65.8%, and realize annual carbon emission mitigation of 18.83 tons. It maintains heating coefficient of performance (COP) and cooling energy efficiency ratio (EER) above 3.0, with average COP and EER at 4.54 and 3.04 respectively.