Configuration Strategy and Applicability of a District Heating Peak-Shaving System Based on Cross-Seasonal Borehole Thermal Energy Storage

• • The optimal BTES configuration requires 630 boreholes, contributing 40.4% of the total peak-shaving heat demand (2.3×10⁴ GJ) over a 1845-hour peak-shaving period, meeting a maximum power demand of 12.4 MW. This demonstrates that BTES can reliably supply a substantial fraction of peak load, reducing reliance on fossil-fuel peaking units. • • The annual cost per unit of extracted heat for the cross-seasonal peak-shaving system is 34% lower than that of a conventional ground source heat pump system, with the added absorption heat pump achieving a levelized cost of 103.4 CNY/GJ at 816 boreholes, and 70.9 CNY/GJ for an existing absorption heat pump configuration. This cost parity with legacy technologies is critical for commercial adoption in district heating networks. • • Increasing borehole count from 396 to 816 reduces the annual cost to 103.4 CNY/GJ for a new absorption heat pump system, while an existing absorption heat pump system reaches 70.9 CNY/GJ, indicating that economies of scale favor larger BTES arrays. This threshold underscores that BTES becomes economically superior to gas boilers and ground source heat pumps beyond 630 boreholes. • • The peak-shaving duration varies from 2210 h to 691 h as the base heating load index ranges from 18 to 26 W/m², with total peak-shaving heat dropping from 3.4×10⁴ GJ to 5.9×10³ GJ. This sensitivity highlights the necessity of accurate load characterization to avoid oversizing the BTES and absorption heat pump, which directly impacts capital recovery.