Techno-economic analysis of a deep borehole heat exchanger coupled heat pump heating system under dynamic building load scenarios

This study performed continuous 10-year simulations of inlet/outlet water temperatures for “deep borehole heat exchanger-coupled heat exchangers in Beijing, Xi’an, and Lhasa using OpenGeoSys software. Simulations of yearly thermal load in three cities, conducted using DEST software, were then combined to evaluate the techno-economic performance of deep borehole heat exchanger-coupled heat pump systems in these locations. Results reveal thermal imbalance in Beijing and Xi’an due to prolonged heating and high loads, causing temperature declines and increased energy costs. Lhasa’s stable geothermal conditions and building thermal resistance minimized fluctuations, reducing energy use by $18 \sim 25 \%$. Building properties significantly influenced efficiency: Beijing’s high heat loss and Lhasa’s balanced design optimized performance. Economically, Lhasa’s stability lowers lifecycle costs, while Beijing and Xi’an require operational adjustments. Region-specific strategies are critical for sustainable geothermal heating in cold regions.