Iron Mountain Data Centers: Geothermal Cooling System

The geothermal cooling mechanism consists of an underground reservoir and a supplementary surface-mounted free-cooling chiller plant. The reservoir is a low-humidity space with consistent water level and temperature year-round. The cooling mechanism has three major design components – reservoir pumps, heat exchangers, and building loop data center pumps – all of which are repeated for capacity and redundancy to meet Tier 3 Data Center Design Standards. The pump works by lifting the water into a heat exchanger where it receives the heat from the data center and rejects it when the warm water from the heat exchanger returns to the reservoir.

The cooling system was commissioned in 2013, added more capacity in 2015, and incorporated the surface-mounted chiller plant in 2018. The addition of the high-efficiency chiller plant served two purposes: another layer of reliability, and increased energy efficiency during the winter months by bringing in supplementary, pre-conditioned outside air.

In addition to the efficient design, the Iron Mountain team continued to look for and implement optimization strategies for additional energy savings opportunities. The team recently found almost 14% additional savings through load shifting and system tuning several years after initial construction.

These ongoing efforts, combined with the innovative cooling system, result in a cost-effective, low power usage effectiveness (PUE), benefitting both the environment and customers.