by Michael Bullock

Cool Ways to Save Money in the Data Center – CRACs and Ultrasonic Humidification

Jan 08, 20094 mins
Data Center

If you’re pushing the limits on the power and cooling you have available in your data center—or you simply want to eliminate wasteful spending on electricity (and who doesn’t?)—I suggest taking a closer look at your facilities infrastructure.  I know there’s some very pluckable low-hanging fruit there that can provide you with a fast, low-risk payback.

I’m not talking about storage and servers; I’m talking about your lighting, UPS (uninterruptible power supply) systems, CRACs (computer room air conditioners), your cooling infrastructure, and humidity control systems.  Since more than half of your power budget can be gobbled up by facilities, this should be the first place to look for savings and efficiencies.  

Here’s one simple example of easily avoidable waste. In most large data centers, the CRAC units are run independently using the factory default settings. Multiple CRAC units will try to maintain relative humidity and temperature in a specific range. When humidity gets too low, they humidify; when the air gets too hot, they cool.  When humidity is perceived to be too high, the CRAC units will dehumidify, and if the air gets too cool, they go into heating mode. However, due to the proximity of the CRAC units’ exhausts and intakes, some systems will be fooled into thinking it’s too humid or too cool in a specific area and start dehumidifying, stop cooling, and add heat. Cool, heat, humidify, dehumidify . . . Get the picture?

Besides wasting electricity, you’re inviting extra wear and tear on the units. That leads to unnecessary (and expensive) maintenance, hardware replacement, and those dreaded service calls.

What’s the solution? Well, first of all, today’s high density server/storage systems produce a constant supply of hot, dry air. Rather than the lush, rainforest-type ecosystem with cartoon vines and twittering birds portrayed in IBM’s popular “Green IT” television commercials, the modern data center environment is more like a desert. Unless your center is in the tropics, you really don’t need dehumidification. Just turn it off. Your servers will do that work for you. However, in order to get the air up to 40 percent relative humidity (the minimum standard called for by most IT equipment) most data centers do require supplemental humidification.

The problem, however, is that most humidification systems were not designed for the constant loads of today’s data centers. Like a pot of boiling water on the stove, these systems rely on steam generation —which has the obvious side effect of raising the data center’s air temperature, making your CRAC units work even harder (and use more power) to cool things off. In other words, you’re adding unnecessary heat that you’ve then got to cool, increasing your spend on power. And, again, let’s not forget the extra wear and tear and maintenance. 

What’s the alternative?

If you install ultrasonic humidification and turn off built-in humidification systems, you’ll create moisture more efficiently without raising air temperature through a steam process. How significant is that?  Well, I’ve seen power consumption cut in half, which I think you’ll agree is pretty substantial. And if your power and cooling needs are forcing you to move into a new facility before you feel ready, making better use of what you already have may buy you some extra time to prepare and do it right.

Furthermore, some of the investments in new facility infrastructure (like ultrasonic humidification) can be recovered immediately through power company rebates.  Paying 40 percent to 50 percent of the equipment and installation costs, the size of the check the energy company writes you will depend on the size of your efficiency improvements. This can get tricky. You’ll need to audit your power usage before and after the upgrades you make to prove to your power company that that’s how you reduced consumption.

So, if you’re reaching the limits of power or cooling, there are things you can do for immediate relief without spending a bundle.  Simply improving your humidification processes can slash power consumption drastically, and taking advantage of power company rebate programs can reduce the payback period to months. And once you make that investment, those savings keep coming.  

I’m sure if you knock on your CFO’s door with these cooler ideas to save money, you’ll get some love. (Well, maybe not love, but attention and support, which ain’t at all bad.)

As always, thank you for sending comments, tips and topic suggestions to me at


Michael Bullock is the founder and CEO of Transitional Data Services (TDS), a consulting firm helping clients implement energy saving green data center solutions, data center relocations, web based enterprise applications and 24/7 technical operations.