Dazigou Coal Mine

At the state-owned Dazigou Coal Mine in Datong, Shanxi, the project covers office and living buildings, production workshops and mine-shaft supply air. With a 5,361.5 kW design load and 90 m3/s shaft-air requirement at no less than 70 C, Sujing combined ultra-low-temperature variable-frequency cascade units with air-source heat pumps in a distributed and centralised design. The first heating season operated well below the tender cost ceiling and provides a practical carbon-reduction path for mining operations.