by Jeff Sheehan, on Aug 29, 2016 11:03:47 AM
In this second installment of a two-part series, we look at the challenge that mega hyper-scale data centers (mega centers) will have in addressing public opinion over their use of water.
The explosive growth of computing demand and storage will necessitate the continued construction of mega centers, and the largest cloud computing providers and colocation developers such as Amazon, CyrusOne, and Digital Realty Trust, among others, will continue to embrace them.
We previously examined the ongoing progress being made with efficiencies in power consumption. As equally important is the efficient and environmentally responsible use of water. Further, as mega centers developers work their long-term strategies, sustainable water availability is weighing more heavily in their decision process.
Innovation reducing the water needed for cooling
Data center operations are known for their use of enormous amounts of water to cool the ever growing raised-floor environment. Keeping data hall’s temperatures within a specific range by managing heat rejection is critical to ongoing operations. Mega centers have traditionally utilized chilled water systems, and this will continue. These chilled systems require large amounts of water to cool the ever-growing number of servers to maintain our appetite for data. The good news is that the improvements and innovation in cooling designs are helping to reduce the necessary water for such operations.
The greater hidden impact mega centers have on water usage goes back to their need for power. Water is critical in the generation of power and with data centers ever-increasing use of available power, the water needed to generate that power must be taken in to consideration when reviewing overall usage. A recent report by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory details such association. The report concluded that water usage in the generation of 1kWh of power is equal to 7.6 liters while an average data center uses 1.8 liters to cool every 1kWh consumed.
California contains the largest concentration of mega centers in the U.S. The state also experiences devastating droughts and, as a result, the allocation of available water is becoming very heated.
Data centers look toward water conservation
Mega center operators fully understand the cost associated with water consumption and are looking for ways to conserve water. The Green Grid Association has developed a metric to help data centers measure water usage effectiveness (WUE). The metric is derived by measuring how much water a facility uses for cooling and other building needs by dividing the annual site water usage in liters by the IT equipment energy usage in kilowatt hours (Kwh). Like the power usage effectiveness (PUE), the metric can help data center managers more efficiently manage data center costs.
One of the simplest and cost effective ways to reduce both water consumption and electrical usage is to locate mega centers in more temperate climates and use the air handlers to draw in cool air in lieu of the AC chillers. Facebook as deployed such a solution in their 290,000-square-foot facility in Lulea, Sweden. The site was initiated as Facebook’s focus on being a good steward of the environment by taking advantage of the abundance of water and the cold climate.
Another method is to raise the temperature of the data hall. Cooling data halls with temperatures cooler than what is needed and with air flow volumes unnecessary is common. Convincing IT managers to raise the thermostat can cause a nervous breakdown but the effectiveness is worth exploring as both water and power consumption are reduced. Acceptance of this should be made easier as the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) revise their guidelines to support such actions.
Bringing liquid directly to the server is a method that has been available for some time which is now gaining traction. The benefits in efficiency in both power and water consumption are promising with absorption of up to 60% of server heat.
Recycling water may be a stretch for some operators as this necessitates onsite water treatment but it provides a means to substantially curb water usage.
Finally, as noted in the first article of the series, managing heat generation is critical as cooling systems account for roughly 30% of energy consumed. Advancements in computer chip’s increasing computing capability results in lowered watts for such operations, thus lowering the cooling necessary to battle heat rejection and thus water usage. Equipment manufacturers have responded by incorporating these improvements into more efficient servers that can operate at higher temperatures.
Conclusions
As a limited resource critical to the operations of our nations data IT demands, the availability of water will continue to be a challenge. Mega center developers will need to incorporate best practices in water efficiency, data center management and continued innovation to meet the insatiable demand.
