Alton/Aztec News Feed

Aztec Indirect Evaporative Cooling Unit on Display at DFW ASHRAE Golf Outing

Mon, 23 Apr 2012 00:00:00 EST

Richard Kirkland, Sales Manager for Business Development, at Mestex exhibited a display version of the Aztec indirect evaporative cooling system at the recent Texas Air Systems sponsored golf tournament for the DFW ASHRAE chapters.

The unit on display was the smallest of the Aztec indirect evaporative cooling line and included the features most in demand for the data center and server room market. DDC controls, VFD supply and cooling tower fans, direct drive plenum supply fan on vibration isolation, and fire resistant fiberglass cooling tower media were all part of the display unit.

Aztec and the National Science Foundation research on data center cooling

Fri, 13 Apr 2012 00:00:00 EST

On April 12, 2012 management and engineering representatives of Aztec, part of Mestex division of Mestek family of products, met with engineering representatives from the University of Texas at Arlington to define how resources will be jointly applied to researching and developing an advanced technology indirect evaporative cooling solution for data centers. Research already started at both organizations will be shared in order to more quickly advance the development of a viable solution to the high rate of energy and water consumption by data centers.

The joint project will be part of the NSF-I/UCRC program. This program, initiated by the National Science Foundation, is a collaboration between 5 major universities and a select group of industry contributors. The stated purpose of the program is to develop commercially viable solutions that will improve energy efficiency in data centers. Research projects range from chip level solutions all the way to complete, large scale, data center solutions. Aztec will be contributing special knowledge of evaporative cooling and outside air cooling solutions that has been developed over 40 years of product development and marketing.

Data Center World 2012

Tue, 20 Mar 2012 00:00:00 EST

We are in Las Vegas at the Data Center World 2012 with the Aztec unit.

Location: The Mirage

Times:

3/20 3:45-6:45

3/21 12:15-3:30

Booth #835

http://www.datacenterworld.com/

New Green Grid "Free Cooling" Maps Published

Fri, 9 Mar 2012 00:00:00 EST

The Green Grid has released White Paper #46 as an update to their "free cooling" maps for data center design and operation. The research was edited by Emerson Network Power, Intel, and Schneider Electric.

The reason for this update to the "free cooling" maps was the latest changes to the ASHRAE TC 9.9 operating/design guidelines for data centers. For those who have not yet seen those new guidelines they allow a much larger operating range for data centers and server rooms that use some of the latest equipment from companies like Dell and HP.

For those of us who are "metric challenged" 40 degrees C = 104 degrees F and 35 degrees C = 95 degrees F.

When you consider that many data center operators still seem to want their rooms at 70 degrees or lower it is clear that these new criteria are a massive change in operation and design concepts. It is also clear that adopting the newest guidelines can result in enormous energy savings.

The Green Grid paper includes a couple of maps to quickly illustrate how extensive the potential for "free cooling" has become under the latest operating/design guidelines. In these maps the darker the blue color the more hours that "free cooling" could be employed. The darkest color blue indicates that all 8760 hours are suitable for "free cooling". The maps also consider the coincident dewpoint temperatures as that metric is important also.

This first map is for ASHRAE Class A3 environments and shows that virtually all of North America could have their data centers cooled without using chillers or compressors. The second map is for ASHRAE Class A2 environments and shows that roughly 80% of North America could still be cooled most of the year with no chillers or compressors.

The question for data center operators and designers who want to implement these new temperatures is what to do about those 500 or 1,000 hours when the outside air conditions are not quite right.

It is still quite possible to operate the center with no compressors or chillers if the designer will incorporate an evaporative cooling system such as the Aztec indirect evaporative cooling system or even the Alton direct evaporative cooling system.

Since evaporative cooling systems operate using 100% outside air all the time they make an excellent "hybrid" approach. During the many hours of the year when "free cooling" will satisfy the conditions either type of evaporative cooling system will provide cool, filtered, outside air. The Aztec indirect evaporative cooling system has the added advantage of allowing recirculation of hot aisle air during the very coldest months when "free cooling" could actually over-cool the data center.

During those few hours of the year, however, when it is simply too warm for "free cooling" to work, the Aztec or Alton systems can automatically initiate their evaporative cooling cycles and trim the outside air temperatures down to levels that fall well within the new ASHRAE guidelines...again, with no compressor or chiller energy required. The air leaving the evaporative cooling system will usually be about 3 degrees F higher than the wet bulb temperature. This chart should give you an idea of the potential air temperature that an evaporative cooling system can provide.

The Green Grid whitepaper is just the latest in a growing number of research papers and documents that point operators and designers in a direction that can save tens of thousands of dollars and kwh if they are willing to make the investment in the latest technologies from both the IT equipment manufacturers and the HVAC equipment manufacturers.

How We Used To Do It

Wed, 7 Mar 2012 00:00:00 EST

I was recently reading an engineering magazine article (I know, I need to get a life) and came across a question that set me to thinking..."how did people stay cool before we had chillers?". After all, in the grand scheme of life we have only had chillers and air conditioning systems for a very short time. So what did people do before those things existed and what can we learn from that?

One of the first lessons from the past is that hot air rises. Seems obvious doesn't it? Believe it or not there is actually a company that is successfully convincing people that by making their air even hotter than everyone else they can do a better job of keeping people comfortable from 20 or 30 feet above them. But that is a different story for another time.

Stack Effect

Because people realized that hot air rises, many early structures in very warm climates would be built with very high roof lines. This would allow the hottest air to stay above the people and increase their comfort. Many of those structures would also have vents or openings at the highest point of the roof so that the hot air could escape. As that hot air left the structure it would be replaced by cooler outside air near the floor level. A continuous circulation pattern would develop that kept the "cooling cycle" going. The taller the structure, and the hotter the air, the faster this cycle would operate. Today, we call that phenomenon "stack effect" and you see it in every tall building elevator shaft in the world. You also see it in chimneys for residences.

After the invention of air conditioning though we seem to have forgotten one of the key elements of this natural cooling cycle...venting the hot air out of the building. In most modern air conditioned buildings we keep the hottest air inside the building and just keep cooling it back down in a constant cycle that requires compressor or chiller energy. In many cases the hot air inside the building is still cooler than the hot air outside the building so this might make sense during the hottest months of the year. However, in the case of a data center or server room, the hot aisle air is usually much hotter than the air outside...but most data centers use cooling equipment that constantly tries to cool down that hot aisle air resulting in huge energy consumption.

Some systems also take advantage of the "stack effect" in a shorter building by recognizing that any heat source in the space will create it's own "mini stack effect". Cooler air will be drawn towards the heat source and the hot air above the heat source can be exhausted. This creates some natural circulation in the space and is one of the key principles behind "displacement ventilation".

Another lesson from the past is that evaporating water will make air cooler. We actually use that very same principle in modern chiller systems that include a cooling tower. The cooling tower is nothing more than a very large evaporative cooler. In the old days people would use wet cloths or reeds in a window opening and when air entered the building through those wet items (probably accelerated by the building "stack effect") the entering air would get cooler and the people would be more comfortable. Today there are many types and sizes of evaporative coolers available, such as those from Alton and Aztec divisions of Mestek, and they work even better than those primitive early methods. But no compressor or chiller energy is required.

Of course there are building construction techniques that are also based on lessons from the past. Positioning a building so that the smallest outside wall area is the one that sees the most sun will help keep the occupants cooler. Using "thermal mass"...thick, heavy, walls...can also keep occupants cooler by storing cool night air energy in the wall and releasing it slowly during the hottest part of the day. Again, we often build very light weight buildings today and try to compensate by adding insulation but nothing beats two feet of solid rock. Some architects are working to revive this technique and research is continuing on using chemical treatments on walls and ceilings that allow them to store energy longer. One case where creating a lot of "thermal mass" might not be such a good idea is in the data center world. Depending upon how the hot aisle air is handled it might actually be a good idea to make the walls very thin so that the heat can escape to the outside through the walls. Finally, the use of shades and window coverings is also a key lesson from the past. Some companies, such as the American Warming division of Mestek, offer exterior solar shades that actually track the position of the sun and change angle in order to maximize the shading effect.

There are many other lessons from the past that could be discussed but the key is to stop and think about how we used to do things. Sometimes adapting ideas from the past to ideas from today can result in the best overall solution.

Mission Critical Magazine Article Regarding Waste in Data Center Cooling

Thu, 16 Feb 2012 00:00:00 EST

Recently there was an interesting article published in Mission Critical magazine that addressed cooling in data centers. More specifically the article addressed the waste that is currently happening in many, many data centers by operating the center at too low a temperature.

ASHRAE TC 9.9, at the urging of IT equipment manufacturers, has been raising the recommended and allowable temperature and humidity ranges for all types of IT equipment. There are now certain classes of equipment that have allowable operating temperatures of 113 degrees F and 80% RH...but we still see data center designs that call for 60 to 70 degree air entering the servers. Even the most critical classes allow temperatures of 80 degrees F and 60% RH.

One of the reasons that is often presented for operating the center at such low temperatures is reliability. There is now research that suggests that this is not a valid concern.

The article in Mission Critical magazine, authored by Mark Monroe, cites a few interesting bits of information.

Using the Arrhenius model for predicting MTBF (mean time between failure), raising the server inlet temperature from 77 degrees F to 104 degrees F reduced the MTBF from 15 years to 13 years...both probably well beyond the replacement cycle for the servers. Given that prediction why run servers at even 80 degrees?

A second study by E. Pinherio, W.D. Weber, and L. A. Barroso’s (2007), “Failure Trends in a Large Disk Drive Population,” determined that there was no discernible relationship between disk drive failures and operating temperature.

Finally, Intel provided information to ASHRAE that allowed creation of a reliability factor calculation that was time and temperature based. This "X-Factor" could be used to estimate changes in reliability from a baseline temperature of 68 degrees F. The interesting thing that comes from this is that using an indirect evaporative cooling system, such as the Aztec ASC product line that can provide server inlet temperatures lower than 68ºF for the vast majority of the year, could actually increase reliability according to the algorithm.

The potential operating cost savings are huge. Switching to the Aztec system that offers 100% outside air cooling most of the year, with supplemental evaporative cooling during the extreme highs, could save $67,000/1,000 kw of IT load for the average data center in the US...according to the information in the article.

Data Center Dynamics retrospective look at most important data center developments of 2011

Mon, 30 Jan 2012 00:00:00 EST

Data Center Dynamics is an international organization with a single mission of sharing best practices among data center designers and operators around the world. The organization publishes a trade magazine called "Focus" and they have just released their January, 2012 edition. This edition is a retrospective look at 2011.

One of the articles included comments from some of the industry's leading players in response to two questions: "What was the most important data center development of 2011?" and "What single advancement will most positively impact the data center sector in 2012?"

Some of the responses were:

Bill Kosik; Principal data center energy technologist, HP Enterprise Business Technology Services:

"For the first time in 2011, many of our clients wanted to implement a design temperature of 75 degrees F for the inlet air to the IT equipment." "When you couple increased supply air temperatures with ultra-efficient air-conditioning equipment (indirect evaporative cooling as an example), you start to see PUEs drop into the low 1.2s/upper 1.1s..."

Andrew Donoghue; Analyst, The 451 Group:

"ASHRAE released a white paper....redefined and reclassified new allowable ranges up to 113 degrees F. Higher operating temperatures could mean that new facilities can be built without the need for expensive cooling technology, such as mechanical chillers."

Dileep Bhandarkar; distinguished engineer, Global Foundation Services, Microsoft:

"Broad recognition across the industry that free air cooling technology is now considered mainstream."

Jim Hearnden; Product technologist, data center power and cooling, Dell Services:

"Newer technology will permit higher server intake temperatures, which will be a great step forward in 2012."

The common thread through all of the comments is the drive to lower energy costs by raising server inlet temperatures. Most of the more advanced companies are even going to the point of using 100% outside air with no tempering at all. Aztec indirect evaporative cooling systems from Mestex, a division of Mestek, offer an alternative that filters and cools the air down to within 2 degrees of the wet bulb temperature (usually in the 70 to 80 degree range). This allows the designer and operator to have acceptable server inlet temperatures and still have a very low PUE. For installations that still need some degree of control over the air temperature and desire filtered, clean, air this might be the best solution.

Mestex You Tube Channel is Active

Fri, 9 Dec 2011 00:00:00 EST

Mestex, the Dallas division of Mestek has created a YouTube channel, MestexHVAC (http://www.youtube.com/MestexHVAC?feature=guide). Mestex will start using this format website to post informational and promotional videos. Current videos include information about the LJ Wing MV coil, the Applied Air Dedicated Outdoor Air System, and the Adaptaire DDC control system.

Aztec to Exhibit at Data Center World in March 2012

Fri, 9 Dec 2011 00:00:00 EST

Aztec Evaporative Cooling Solutions, a Mestex (Division of Mestek) company, will be exhibiting their evaporative cooling solution for data centers at the Data Center World Conference and Exhibit. Aztec will be located in booth 835. The exhibit will be March 20-21, 2012, at the Mirage Events Center in Las Vegas. Information about Data Center World can be found at www.datacenterworld.com.

Latency Intolerance

Tue, 13 Sep 2011 00:00:00 EST

Several things occurred almost simultaneously over the last week or so that spurred my thinking for this latest blog post.

The diagram at the left illustrates the network configuration for our DDC control system called Adaptaire. We have launched a project to add some additional functionality to the software that has been around for almost 12 years now. The function that we are adding is a real time "dashboard" that will give the building occupant feedback on how well the system is performing. Because the "dashboard" is displaying information in real time, and might be transmitting that data over the Internet, one of the factors that we need to consider is the speed at which we "refresh" the data.

The second thing that spurred our thinking is our plan to migrate our current product selection software from a desktop environment to a web-based environment. This means that the data entered and the answers received back from the selection software will be transmitted via the Internet. Experiments with some very early versions of the software have highlighted "speed of response" issues that must be addressed as we move forward.

The third event that provoked this blog entry was a meeting with one of the chief design engineers for Integrated Design Group, a data center design firm responsible for projects worldwide. In the course of the discussion this engineer made a prediction that the data center industry will move to more, and smaller, data centers.

The common thread in all of these items is the "need for speed" and that translates into reducing something called "latency". "Latency" is the time it takes for your input, or our dashboard refresh signal, to actually reach its final destination. As incredible as it might seem, even though these signals are moving down fiber-optic cables at the speed of light, it can take a "long" time for that signal to reach its end point. First, remember that "long" in this industry is measured in nanoseconds. Second, remember that most of the signals that are transmitted are actually transmitted at least twice because of error checking. In addition, most of the time those signals pass through several routers and servers before reaching their destination and each of those "hops" also includes error checking and traffic control delays.

One solution, and the reason this engineer believes the future of the industry is more, and smaller, data centers is to locate the data centers as close as possible to the source of the signal or destination of the signal. This will reduce the number of "hops" and also reduce the physical distance between points...thus reducing "latency".

The "latency" issue is so important in industries like equity trading that data center companies are battling each other to locate their facility just one block closer to the Wall Street trading floor.

We are all becoming spoiled by the speed at which we can find information via the Internet, download music, watch on-line videos, etc....but the end result is that we are acquiring a new "disease" that I am calling "Latency Intolerance".