Experimental study on cooling performance of underground pipe gallery ventilation enhanced by borehole heat exchanger

The building’s underground pipe gallery can efficiently accommodate and consolidate various types of pipes, thereby enhancing land use efficiency. However, the abundant geothermal resources around the gallery remain underutilized. Shallow geothermal energy offers effective temperature regulation, providing warmth in winter and coolness in summer, thereby facilitating climate control in built environments. Research on the ventilation and heat exchange properties of these galleries remains limited. In this paper, a coupling system of cooling and ventilation in summer, which combines an underground pipe gallery with 6 U-shaped borehole heat exchangers, is studied. The performance of the system was evaluated by a full-scale experimental platform, and the cooling efficiency and the influence on the thermal environment of the room were explored under extreme weather conditions by directly using the underground pipe gallery and borehole heat exchanger to enhance cooling. The results showed that a significant temperature reduction of over 9.9 °C was achieved within the gallery. The cooling capacity is affected by ventilation volume, with lower volumes improving air-gallery heat exchange efficiency but reducing overall cooling capacity. Maximum cooling at a ventilation rate of 1918.8 m3/h was 10.2 kW. The operation of the borehole heat exchanger significantly improved efficiency, with an average temperature reduction of over 16 °C and a peak cooling capacity of 13.3 kW, resulting in the test room being 1–2 °C cooler than a control room. Maximizing thermal comfort can significantly reduce air conditioning energy requirements. This research contributes to sustainable building design by quantitatively validating an underground pipe gallery coupled borehole heat exchanger system's cooling performance, offering a viable alternative to traditional energy sources for building air conditioning. It provides a sustainable and efficient climate control solution for the built environment.