Personnel and cable grounding to guard against damage to the equipment due to electrostatic discharge (ESD), allowing lower IT equipment intake humidity in a data center.
Too much humidity in supply air can lead to condensation, which can in turn cause corrosion or—in sufficient amounts—electrical shorts that trip circuit breakers, damage equipment, or harm electrical circuits within the data center. High humidity and condensation can also cause rust and corrosion in servers, leading to machine failures. But too little humidity promotes buildup of electrostatic charge, and discharges of static electricity can damage or destroy sensitive electronics. Recent studies indicate that high humidity is rarely an issue in most data centers as the temperature of IT equipment is significantly higher than that of the cooling coil operating dew-point. Furthermore, most IT equipment is rated for operation up to 80% RH.
Low humidity during the cold winter season can be problematic as individuals working with circuit boards need to be grounded to prevent static discharge on to the board and damaging the circuitry. Static potential increases as the relative humidity decreases. To reduce the potential for electro-static discharge (ESD), data centers can be equipped with humidification. Humidification system can use a lot of energy, from 25 to 380 watts-hours per pound of mist, depending on the type of equipment used to introduce moisture into the air stream.
This ET proposes to ground the racks, floors and people thereby allowing the relative humidity to decrease below 40%. A study done several years showed that whenever relative humidity dipped below 30%, there would be a measurable increase in equipment failures over the next several weeks (Ground, 2013). The grounding products should be used in conjunction with other humidity control strategies, such as using outdoor air, enthalpy controlled economizer, coil temperatures above 55 degrees, use lower power humidification technologies, etc. for the most energy efficient design.
Status:
Baseline Description: Humidifiers in Data Centers Baseline Energy Use: 1108 kWh per year per pound of steam
A computer room air conditioning (CRAC) unit is a device that monitors and maintains the temperature, air distribution and humidity in a network room or data center. CRAC units can use different approaches for humidity control with humidifier energy use dependent upon the selected approach. Energy Star notes that ultrasonic humidifiers use only 25 watts-hours of electricity for each pound of mist generated versus 380 watts-hours for electric steam generators/boilers. In addition, ultrasonic humidifiers produce a free-cooling effect as they absorb heat from the supply air as the water droplets evaporate. Assume that a conventional steam generator is in use for the four winter months. Energy use/pound = 0.38 kW x (.333) x 8760 hours/year = 1,108 kWh/year
"Typical" Savings: 1% Savings Range: From 1% to 1%
Savings must be determined on a site by site basis. Many variables weigh into the savings. Affecting the humidity is significant, but, grounding the people and cabinets is the zero energy way to address static discharge disruptions.
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
Panduit Ground, 01/01/2013. Structured Ground Panduit , 1 Special Notes: Catalog of all the parts and pieces needed for ESD elimination strategy.
Energy Star, 02/05/2015. Server Inlet Temperature and Humidity Adjustments EPA
Technical Advisory Group: 2013 Information Technology TAG (#8) TAG Ranking: 50 out of 57 Average TAG Rating: 1.85 out of 5 TAG Ranking Date: 10/25/2013 TAG Rating Commentary: Difficult to quantify savings ESD is not a problem. All IT equipment is qualified to withstand ESD. Unless equipment is being opened and worked on, there should be no need for grounding straps. Certainly not emerging! Not an ET.