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What the California Drought Reminds Us About Data Center Design

California Drought and Data Centers

The Water Use Associated with Data Centers Hasn’t Gained A lot of Attention – Maybe Its Time that It Did.

The State of California has been battling massive drought for months now.  In April, California Governor Jerry Brown announced the first-ever statewide water reduction mandate, which requires cities and towns across the state to reduce water use by 25%.  The impact of the California drought and water reduction mandates on the agricultural industries has been widely reported, but little has been said about the role data centers play in water consumption and the ongoing drought issues that the State is facing.

California is home to some of the country’s largest data centers and cloud computing facilities.  While the total energy consumption of these facilities has gained a lot of attention, the water use associated with large data centers has not.  Many data centers are designed to use cooling towers as heat rejection and as a result they can consume water in a couple of different ways:  extracting water from a public source and losing water to the environment through the process of evaporation.

data center design drawing

Because hot return water is evaporated at the cooling tower (to reject heat), “makeup” water is continually required from a public water source to support data center cooling.  To put a large data center in perspective, the new NSA Data Center in Utah could require up to 1.7 million gallons of water per day to operate.

This is not to say that work has not been done to reduce the water usage at data center sites and/or draw attention to this issue.  Some additional options for data center cooling strategies are:

  • Using Non Potable or Recycled Water: Google (and others) have used non-potable water sources to cool their data centers, like the sea-water cooled site in Finland.
  • Direct Air Economizer: Facebook (and others) are using direct air economization designs for data center cooling, where outside air is drawn in and supplied to the IT equipment.  In most cases this requires water ‘mist’ to be sprayed into the air stream, but the amount of water required is a significantly less than a traditional cooling tower design.
  • Packaged Chiller:  Many data centers could consider a closed-loop chiller design with a waterside economizer.  This strategy removes the use of a cooling tower and significantly reduces potable water usage.

Using cooling towers has been a component of data center design for many years.  The drought in California should remind us that ensuring the sustainability of a data center facility encompasses not only an energy-efficient design but also a sustainable strategy for water use.  As an owner, challenge your data center design team and your internal organization to think beyond ‘energy efficiency’ and more toward the overall impact your data center is having on our environment.  Water is a finite resource and the overall water use of your data center facility should not be overlooked.

Additional Resources:

  1. Explanation of leveraging free cooling without the need for open-cell cooling towers (whitepaper)
  2. The Green Grid Water Usage Effectiveness (WUE) Whitepaper
  3. Facebook’s real-time water usage tracking

Tell us what your data center is doing to conserve water. We want to hear about it.