Sustainable underground environment integrating hybrid ventilation, photovoltaic thermal and ground source heat pump

Sustainable underground environments face 'high temperature, humidity and pollution' from heavy internal loads and warming climate. Relying on mechanical ventilation and ignoring the 'soil-building-atmosphere' coupling cause energy wastage and soil thermal imbalance. This study discusses the sustainable design of multienergy coupling and hybrid ventilation for underground environments. Furthermore, this study proposes a novel system combining hybrid ventilation, photovoltaic thermal (PVT) and ground source heat pump (GSHP) to integrate energies from the atmosphere, shallow and deep soil and solar and waste heat. On the one hand, PVT pipes and solar radiation heat solar chimneys to produce stable thermal pressure ventilation. On the other hand, GSHP efficiently exchanges heat in deeper soil to regulate the indoor environment and cool the PVT pipes. TRNSYS coupled with CONTAM implements 'electric-heat-airflow' coupling simulations to assess various sys-tem performances. This system's performance in different climates is analysed from soil thermal balance, energy efficiency, hybrid ventilation and PVT generation. This study hopes to offer inspiration and a design method of multienergy coupling for exploring sustainable underground environments.