New ASHRAE Study Will Encourage Data Centers to Operate at a Lower Relative Humidity

Mike Donoghue
April 8, 2015

For the last several years, ASHRAE has been advocating that data centers allow temperatures to rise in order to save money on cooling resources.  Now, an upcoming study will assert that data centers save even further by allowing humidity to drop to an RH of 8 percent.

In a recent interview with Data Center Dynamics, Dan Beaty, Cofounder of ASHRAE’s TC 9.9 said, “We ran a test with different types of floor tiles and clothing, and we found that between eight percent and 20-25 percent, the difference in static electricity is insignificant.”

The finding could lead to significant operational cost savings.  According to EnergyStar.Gov[1]:

A typical data center uses a great deal of energy maintaining humidity through multiple CRAC units. Each CRAC unit has the ability to humidify, de-humidify, heat and cool. When humidity gets too low, a typical CRAC unit will raise the humidity by using inefficient infrared or steam canister humidifiers. These humidifiers can use an order of magnitude more energy than adiabatic humidifiers (e.g., an ultrasonic humidifier) and can also raise the temperature of the data center because they produce heat to generate steam.

Moving forward, data centers can meet ASHRAE’s updated recommendations for temperature and humidity by using environmental sensors along with DCIM software.  Sensors are an inexpensive, easy-to-deploy technology that makes it easier for facilities managers to monitor rows and racks and adjust CRAC and CRAHs to make optimal use of cooling resources.

The data can be plotted on a psychrometric chart to allow users to easily compare the real-time temperature and humidity data collected from environmental sensors in cabinets against the environmental envelope of target operating zones displayed on a psychrometric chart, ensuring optimal conditions for the operation of critical IT systems in compliance with the new ASHRAE guidelines.

Want to improve your data center environment management? Read our white paper, "Environmental Data Center Management and Monitoring" to learn whether you're already on the right path and whether there's room for improvement. 

[1] https://www.energystar.gov/index.cfm?c=power_mgt.datacenter_efficiency_inlet_temp