The safe and effective operation of a science facility deep underground poses a number of ventilation and cooling challenges. Ventilation air must be delivered from the surface to the occupied space and conditioned to meet the space requirements. Exhaust air and heat generated by the facility and its supporting infrastructure must be removed from the underground spaces and rejected back to the surface. The mechanical design must overcome these challenges while limiting its footprint given the high cost of underground excavation.
This paper will present the details of the mechanical ventilation and cooling design for a science facility located 4,850 ft underground in a former gold mine. The site will be comprised of 3 large caverns and a network of tunnels to be excavated over 6 phases. The installation of airside and waterside equipment will take place as the excavation proceeds posing operational challenges in meeting the space requirements. Mine ventilation air will be cooled and supplied to the experiment caverns through water cooled air handling units picking up heat from the spaces. Exhaust fans remove air from the space meeting the air change requirement and deliver the air to an underground spray chamber. The spray chamber is an excavated space where condenser water from the chiller is sprayed into the exhaust airstream. The exhaust airstream picks up heat from the sprayed water and returns to the surface through a vertical borehole while cooled condenser water returns to the chillers.
The paper also presents the constructability considerations which are a result of the phased excavation and operation of the facility. The mechanical design is flexible to limit the incremental changes between phases while maximizing the use of the excavated space and minimizing the client’s costs.
