Politics and the Building Industry

Climate Change Initiative

Coal Fired Power Plants in Danger

I am not sure how many folks listened to President Obama's speech this week regarding climate change initiatives.  I know that I was not one.  However, I have read the document that served as the background for the speech and there are some things in this document that folks in the building design community and mission critical world, in particular, should pay attention to.  Those things could have a significant impact on the types of systems that we can design and implement in the coming years.

The theme of the speech and the document is primarily reduction of carbon emissions and increases in "renewable" sources of energy.  There are some other things in the document that are focused on electric generation infrastructure.  However there is a potentially ominous element to that topic that is related to the overarching goal of reducing carbon emissions. 

By means of a "Presidential Memorandum" Mr. Obama has instructed the EPA to accelerate transitioning power plants to "clean" energy sources, i.e. anything but coal.  As we have seen in some other cases in the HVAC industry as soon as the EPA has a mandate of that sort they move quickly to implement regulations that may, or may not, be carefully thought out for the old "unintended consequences" issue.

In my opinion the danger is rapidly removing significant generating capacity from the grid at a pace that cannot be matched on the construction side.  Even though the document also outlines a directive to speed up permitting of power plants it is still a fact that building a multi-megawatt power plant can take years.  With coal being the primary energy source for roughly 40% of US power plants you can see how a too quick implementation of rules that curtail their use can lead to problems.  Many states already operate on the edge of rolling blackouts and brownouts each summer so shutting down or limiting coal fired plants could get ugly.

Exacerbating this problem is the rapid and continuing growth of the data center market.  When these things come on line they gobble up megawatts of generating capacity in a single site...and they can come on line in a matter of months, not years.  Even if they never reach full utilization the power companies must be prepared to provide that power.  ASHRAE and others have tried, somewhat in vain, to communicate that these centers can operate without the heavy energy use of compressors or chillers.  As long as the local electric utility still has generating capacity that can be allocated to the data center this is OK...although not a very "sustainable" approach if you believe in that concept.  But, if that same utility now has to shut down 10 or 20 percent of its generating capacity then there may simply not be enough power to allow the luxury of overly cold air in the data center.

The implications for other building types are similar, although not nearly as extreme.  Systems that optimize the use of outside air as their primary cooling source augmented by smaller compressor or chiller plants could become the basis of design.  Concepts such as chilled beams that utilize higher chilled water temperatures and minimal fan power might need to migrate to smaller buildings than you see them in today.  And building shells will need to make more extensive use of passive and active shading systems.

So, once again, the building industry is going to be impacted by external forces that may have the best of intentions but that will also require rethinking of how we design and operate those buildings.

Trusting The Weatherman

Designing to a Standard

It is an interesting fact that many projects are "over-designed".  This is nothing especially new but it seems that we are seeing more of it lately.  As an example we are currently working on a project that will be located north of Detroit but is being designed to operate at temperatures that exceed the ASHRAE 0.4% design criteria for Phoenix.  On the surface this seems to be overkill in the extreme.  The increase in capital costs for equipment that will probably never have to perform to that level could easily drive the project over budget.

The psychology behind making design decisions of that type basically indicates a lack of confidence.  The end-user chooses to ignore the ASHRAE climactic weather data and recommended design points because he or she lacks confidence in the data.  Personal experience of temperatures that exceed the published design conditions add to the lack of confidence in the recognized standard.  ASHRAE has tried to address this by also publishing the 10, 20, and 50 year maximum (or minimum) recorded temperatures.

This criteria is similar to the "100 year flood" criteria that civil and site planning engineers use.  Many of us have seen, or experienced, times when the "100 year flood" line has not only been crossed but crossed multiple times.  At a recent meeting that I chaired we had a presentation by a well regarded environmental and site planning engineer.  The presentation showed how the location of various coastal high water design lines have changed over the last few years...moving further inland and changing the flood insurance status of existing structures that were originally well outside of the potential flood area.

Could it be that the climate is actually changing as many people suggest?  Do we need to revisit our temperature design criteria more often?  The alternative is to ignore the standard and add an arbitrary "risk premium" to the design criteria...adding costs that might not be necessary.

When I was a young consulting engineer many years ago I was told to design to the ASHRAE design points.  One reason was that by using a recognized standard I could always fall back on that point as evidence that I had used proper engineering practices in my design.  The nature of mechanical equipment was such that most systems ended up over-sized anyway and could throttle their performance to meet the criteria.  If owners today add a "risk premium" to their design criteria...and then the mechanical equipment also ends up over-sized...then the capital costs and system capacities are doubly over stated.  As we move towards a market where building operating characteristics are posted by the front door, much like an automobile's gas mileage rating, the practice of arbitrarily over-sizing systems will put some owners at a disadvantage when it comes time to lease the space.

So You Think Your Critical Cooling System Is Reliable?

An HVAC system with 3 components in series

System Reliability Versus System Complexity

 

I just read an article in Engineered Systems magazine that reminded me of one of my own blog postings from a few months ago.  The difference is that the author in the ES magazine article went all mathematical on us and showed the formulas for calculating HVAC system reliability given the reliability of the individual components in the system.  Although it was a long time ago I remember going through the mathematical exercise in one of my engineering courses back at the University of Texas...so we have all known about this procedure for a very long time.

During this same week I have been asked to do a competitive analysis on a "new" system concept compared to one of our systems.  While I could name names that is not necessarily the important point of this posting.  What struck me about the competitor's "new" system concept was just how many parts were required to accomplish the task of providing "free cooling".  Many of those component parts had dependencies that meant that the proper reliability analysis was the "series" analysis.  You can refer to the latest issue of Engineered Systems if you don't remember what that means but in keeping with my simple approach to my postings the bottom line is that the reliability of a "series" of components is the compounded product of each item's reliability multiplied together.  In other words if the "new" system concept required 4 compressors that are staged in series, a direct drive exhaust fan array, a direct drive supply fan array, a sensible heat wheel motor, sensible heat wheel belt, sensible heat wheel bearings, digital control module, etc...and we gave each of those items a reliability of 98% (which sounds pretty good and is generous for some of the items in the chain)...then the "system" reliability would be:

 

.98 x .98 x .98 x .98 (compressor section) x .98 (exhaust fan) x .98 (supply fan) x .98 (sensible heat wheel motor) x .98 (sensible heat wheel belt) x .98 (sensible heat wheel bearings) x .98 (digital control module) = .817

So, the "new" system concept under this scenario would actually have a reliability of only 81.7%...not quite so good I think you would agree. 

The information from this example is actually directly from the competitor's product literature...and I left out some components for simplicity sake.  The reliability of the components at .98 was an estimate and you can plug in whatever numbers you think are accurate.  The important thing is to recognize that the more complex the system is the lower the reliability will be.

In a previous blog posting I quoted Albert Einstein who said ..."make everything as simple as possible, but not simpler.".  I still think Albert was a pretty smart guy and when I look at some of the design solutions being proposed today for data centers, pharmaceutical warehouses, or cooling in general I just have to wonder why we sometimes design such complex solutions. 

Remember..."it is not sustainable if it is not maintainable"...and, as a corollary to that statement, "it is not maintainable if it is too complex and has too many parts".

The Changing Face of Real Estate

One of my more enjoyable activities that I have is to act as chairman for a developers forum as part of the NAIOP organization.  This activity provides insights into the thinking, planning, and expectations of commercial and industrial property developers and owners across North America.  At our annual meeting a couple of months ago there were many presentations and discussions that focused on 2013 and beyond.  I thought I would share just a few of the points from that meeting.

The NAIOP Research directors provided some interesting factors to consider going forward that tended to revolve around the way technology is changing the office and industrial markets.  E-commerce is projected to have a negative impact on mom-and-pop retail and small start-up retailers until the housing market makes a big recovery, according to Cassidy Turley-Terranomics.  They went on to say that while middle market retailers will continue to struggle, the luxury and discount retailers will continue to expand and open new retail and distribution facilities. 

Speaking of distribution facilities, Jones Lang LasSalle indicated that they believe that distribution center users will continue to push for higher bays...up to at least 36 clear feet...in order to increase efficiencies in handling e-commerce transactions.  Another interesting impact of e-commerce that was highlighted by IMS Worldwide and by Liberty Property Trust is that changing real estate requirement for an e-commerce focused distribution center.  The number of transactions per day in an e-commerce site can be 10 times greater than for a traditional distribution center.  Each of those transactions must be touched by someone so the number of employees in an e-commerce center is much higher.  Parking for up to 1,000 cars in addition to trucks means the land required for these centers can be 40 or 50 acres greater than a comparable "traditional" distribution center.  Implied in this scenario is also the need for a temperature controlled work environment for those 1,000 workers instead of the old "just keep the pipes from freezing" distribution or cross-dock environment.

Another impact of technology and e-commerce is that a DC ("distribution center") for e-commerce has an element of "mission critical" to it in order to process all of the transactions.  Developers and users of these new types of distribution centers look for locations that have reliable fiber optic and cable network access, as well as dual primary power substations in order to minimize downtime in the event of a power disruption.  Other location related decision criteria include being in a right-to-work state and in a state that does not charge sales tax on e-commerce transactions.

Shifting back to the office market, CBRE-Canada, noted that employees are changing how they work and the traditional office with walls is going away.  They also noted that employees, especially the younger ones, communicate with each other by text message versus phone reducing the "noise level" in the office down to the clicking of small touchscreens...reducing the need for walls to control cross conversations.

PPR/CoStar commented that the average lease that they see in the office market has decreased from 5,000 square feet to 3,600 square feet.  This statistic is reinforced by the results of a CoreNet survey of 500 corporate real estate executives who have changed their office plan metric from 225 square feet per employee down to 175 square feet in 2012 with a projection of only 150 square feet by 2017.  This change means that development of new buildings will continue to be pressured as it will take longer to absorb space in overbuilt markets. 

The final point from the annual meeting is that while there is abundant capital available for the right deal all of these other factors are driving developers to spend that capital on remodeling and repurposing of existing space. 

How I Spent My Summer Vacation

It has been a while since I have posted anything to this blog...no, I was not on sabbatical on some desert island...I have been traveling around North America talking to consulting engineers, contractors, and data center owners and operators.  This posting just provides a few insights that I garnered over the last 2 months on the road.

First, the data center/mission critical market continues to occupy the minds and the design resources of many, many companies in the design community.  It is clear that this is a market segment that is vibrant and all indications are that it will continue to be for quite some time to come.  The latest issue of Datacenter Dynamics FOCUS indicated that the world is now consuming over 300 Tkwh annually to drive data centers, with the US consuming over 25 Tkwh alone.  The consumption in the US is projected to grow over 9% in 2013.  While this information points to a growing market it also points to the urgent need for improved operating efficiency in data centers.

Second, and related to the first item, is the lack of knowledge about new "best practices" in data center design.  I have talked to dozens of engineers, contractors, and data center people who are not aware of the latest design guidelines from ASHRAE.  In fairness, those guidelines were only officially announced a few weeks ago...but they have been rumored and discussed for about a year now.  I mentioned in one of my earlier posts that education of the design community is an important, and ongoing, task.  This has been reinforced to me over the last 2 months.

Third, for those engineers and contractors who understand and embrace the new standards, is the challenge of convincing the data center people to adopt those standards.  This is less of a problem at the top levels of the data center company than it is on the floor of the data center.  The IT equipment operators who live in "the white space" seem not to understand the allowable operating temperatures of the equipment that they manage every day.  I have heard many different reasons for their reluctance to adopt the new best practices but I think it comes down to fear.  Because of stringent SLAs the operators worry about losing any equipment for any period of time...even though there is mounting research that this fear is unfounded.

Fourth, I have heard of several cases where the local electric utility has started to put limits on the available service capacity for planned centers.  In the US we are so comfortable with the idea that our electric grid can provide unlimited power that we forget that is not true.  We have a fixed number of powerplants with only so much generating capacity.  With the tremendous growth of data centers, and data centers with 300 to 500 watt per square foot electrical demands, there is a limit to what a utility can do.  And timing is another element of the equation.  A data center can be built in a matter of months...a powerplant takes years.  So even when a utility sees the demand coming they cannot add capacity as quickly as the demand can be added.

So, these are a few observations from the last couple of months.  Of course there is more to the story and feel free to comment on this post with any questions you might have.  I will try to respond as quickly as possible.

Direct Evaporative Cooling Analysis for Two Diverse Climates

One of the common concerns expressed about the use of evaporative cooling for data centers, server rooms, telecom facilities, or other facilities housing heat producing electronics is the ability of evaporative cooling to achieve the target inlet conditions for the electronics.

These two psychrometric charts show the results of an actual analysis in two distinctly different climates.  The target server inlet temperatures were between 65 and 85 degrees F and between 20% and 80% RH.  The mechanical system criteria mandated that direct evaporative cooling be used.

The proposed mechanical system consisted of a direct evaporative cooling system with 12" cellulose media, a steam humidifier, DDC controls, and a hot aisle/outside air mixing section.  The controls would be configured to modulate the outside air dampers, hot aisle dampers, evap media water flow, and the humidifier to maintain the target conditions.

Server Inlet Temperatures from Evaporative Cooling System in Pacific Northwest US

Server Inlet Temperatures from Evaporative Cooling System in Southeastern US

As you can see from the charts the proposed system would easily achieve the desired results.  In fact, it was found that outside air cooling could achieve the targets during roughly 15% of the year, direct evaporative cooling could achieve the results during roughly 60% of the year, and remaining hours of the year when the air was too cold to properly operate the evaporative cooling without fear of freezing a combination of hot aisle and outside air supplemented with the humidifier would hit the target.  The only excursions of temperature over the maximum target of 85 degrees would occur for no more than 5 hours a year based on the NOAA TMY2 weather history.

While not every location would achieve these results the diversity of climate for these two studies imply that direct evaporative cooling, with creative use of mixing and controls, will work in many more climates than most people expect.  To further expand the capabilities of evaporative cooling an indirect evaporative cooling element could be provided to produce even broader temperature control.  Although it was not analyzed for this case we would expect that adding an indirect evaporative cooling element to these systems would have eliminated the few hours of excursion above the maximum dry bulb temperature.

As a means to dramatically reduce energy consumption for these data modules the evaporative cooling solutions such as those manufactured by the Aztec division of Mestek would prove to be extremely effective.  Since evaporative cooling systems are also relatively simple mechanical systems with no refrigerants maintenance of the systems does not require licensed refrigeration technicians and there are very few elements that could fail...increasing uptime and providing much faster recovery time should a repair be necessary.

Aztec Evaporative Cooling Solutions attends Data Center World Expo

Aztec Evaporative Cooling Solutions, a division of Mestek produced in the Mestex (Dallas) facility, was present at the recent Data Center World Expo in Las Vegas.  Aztec was showing an example of the ASC indirect evaporative cooling solution for data centers, server rooms, telecomm facilities, or IT product research labs.  The unit on display highlighted the system's integrated cooling tower technology, integrated DDC control system with multiple sensor options and BacNet or IP access, isolated direct drive plenum fan assembly designed for up to 200,000 hours of operation, and variable frequency drives for both cooling tower and supply fans. 
 
The show was attended by IT facility professionals from all over north America and Mexico.  Roughly 80 vendors were displaying an array of infrastructure products for data centers ranging from power distribution systems to cooling equipment.  Also visible in many booths were thermal and power simulation tools and DCIM software. 

The Aztec ASC system was the only factory assembled and tested evaporative cooling option for data centers that was on display.  Designed for long life, and with a history of extremely low failure rates, the Aztec ASC was considered to be a viable solution for many of the attendees.

Green Grid Updates Free Cooling Maps for Data Centers

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

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.

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.

Prineville Server Farm with "free cooling"

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.

Ten Reasons to Tone Down on Climate Control

Sometimes the best thing to do is to acknowledge when someone else does something right.  In this case Nicholas Greene posted an article on TechAxcess that sums up the ten reasons why data center designers and operators should adopt modern cooling design criteria for their centers.  Nicholas clearly articulates the reasons and I cannot improve on what he says.

I can only reinforce the message that there are alternative cooling methods that can provide cool...not cold...filtered, clean, air for data centers.  Aztec Indirect Evaporative Cooling Systems from the Mestex division of Mestek can send 65 to 80 degree air to the cold aisle and allow the designer to exhaust 100% of the heat from the hot aisle without using any refrigerants or compressors.  The result is cold aisle conditions that meet the latest ASHRAE TC 9.9 criteria and that address the issues that Nicholas covered in his article.

As Nicholas says...it is time for operators and designers outside of the "big names" to get on board and start implementing these energy saving technologies.

GreenBuild Toronto

This past week I was able to participate in the GreenBuild conference in Toronto.  This was my first opportunity to attend and I have come away with a few impressions.

First, I was surprised at the sheer size of the exhibit area.  The Metro Toronto exhibit hall is quite large and split into two sections spanning the CN Rail lines in downtown Toronto.  Both sections were completely full with exhibits for everything from flooring to roofing and everything in between.  All exhibitors promoted the "green" or "sustainable" aspects of their products...even if those aspects might not have been obvious on first or even second thought.  In addition to the three Mestek HVAC product booths the exhibit area included product displays from most of the major north American HVAC manufacturers.

The HVAC equipment companies, as well as many of the lighting and appliance companies, shared one common thread.  That is the emphasis on the "man-machine interface"...how the user interacts with the equipment for control or information.  Touch screen displays were everywhere providing access to virtual control points and providing occupant feedback on temperatures and, most importantly, energy utilization.  The degree of sophistication of the displays varied but the message was the same...in order to conserve energy people must have some sense of how much they are using.  It goes back to the old saying that "you can't manage what you can't measure".  The use of energy metrics have been proven to change occupant behavior and the HVAC industry is stepping up to help with that effort.

Mestex started our efforts in that regard several years ago with our Adaptaire DDC control system and we currently provide basic control and trending information via the Internet.  More developments are underway to further enhance the user feedback and help focus their attention on conservation of our energy resources.

Mestex has been providing this open protocol system for almost 10 years and has successfully integrated with virtually every other major control protocol on the market.  This has allowed building owners to gain visibility into the various Mestex brand products through their own building automation system in order to provide a richer set of points for monitoring and control.

News Item - US DOE Planning Building Rating System

For those who might not have seen this through their own trade associations here is an announcement of a program being planned by the US DOE. It sounds similar to programs in some European countries. There is a link to a webinar for more information about the proposed program.

The U.S. Department of Energy (the Department) is planning to develop a voluntary national Asset Rating Program for Commercial Buildings (AR Program). Through the AR Program, DOE intends to establish a building Asset Rating system that can be broadly applied to both new and existing commercial buildings, and provide affordable and reliable information to building stakeholders. The AR Program will inform building owners about the energy efficiency of their building systems, enabling comparison of the energy performance between buildings while accounting for differences in building operations and occupant behavior. The intent of the AR Program is also to help building owners identify opportunities for energy efficiency improvements.

DOE seeks the input of stakeholders and interested parties, and has issued a Request for Information (RFI) to solicit input on key issues associated with the development of an AR Program. DOE will be hosting a webinar for interested parties on August 23, 2011, at 12 p.m. (ET) to facilitate discussion on this issue. To attend the webinar, please register here to receive further information.

Do Evaporative Cooling Systems Use Too Much Water?

One of the issues that will ultimately confront designers when considering evaporative cooling solutions for data centers, or any other application for that matter, is the issue of water use. Considering that water is already an increasingly scarce resource in many areas, with projections that the situation will only get worse, it is important to consider this issue. In the data center design world the common metric of efficiency is known as the PUE but many people want to use a new metric, WUE, to reflect the water use efficiency of the data center.

Evaluating water use efficiency can be pretty tedious and is very dependent upon the location, the type of HVAC cooling system being used, and the type of electrical power plant providing the power to the building. Why do we consider the electrical power plant? Because we need to remember that electrical power plants consume vast amounts of water in the process of generating electricity and that about 70% of the power generated is lost in transmission and generation inefficiencies.

The US Geological Survey has published average water consumption rates for various types of power plants. Nuclear plants consume, on average, as much as 720 gallons per MW-h. Natural gas fired plants, commonly used for peaking plants, consume on average as much as 180 gallons per MW-h. And, coal fired plants, representing almost half of all US power plants, use on average 480 gallons per MW-h.

An additional impact of power generation is the increase in local water temperature near the cooling discharge of the typical “once-thru” plant design. (Recirculating designs are rare due to the huge increase in construction costs that they incur) This increased water temperature has ecological impacts on fish and plant life near the power plant. There is also an ecological impact near the cooling water intakes as the suction pressure of the cooling pumps is such that small fish and aquatic animals are pulled into the intake screens where they die.

So in order to accurately assess whether or not an evaporative cooling solution uses too much water it must be compared to the water use by the power plant that is providing the energy to the HVAC systems that are being compared. This becomes difficult due to the wide range of system types and locations but let’s look at a representative example using some common rules of thumb.

A typical indirect evaporative cooling unit, such as the Aztec ASC-50, will use about .25 kw/ton of energy to provide roughly 150 kw of cooling capacity. A packaged DX rooftop unit with and EER of 10.1 will use about 1.15 kw/ton to do the same amount of work. And a modern air cooled chiller will use about .88 kw/ton for the same cooling effect.

The table below shows the power required, in kw, to produce 50 tons of cooling effect from these three system types. The Aztec water consumption is a combination of the electrical power required plus the evaporation and bleed rates for the evaporative cooling process.



Using the figures from the US Geological Survey we calculated the water use for the two most common power plant types (coal is used to generate 50% of US power and natural gas is used to generate 20%). You can see that, for the most commonly used power source, the Aztec ASC indirect evaporative cooling system actually uses LESS water than the air cooled HVAC systems for the same amount of work. Of course this does not consider the environmental impact of the heated water discharge into the local reservoir from the electric power plant.

Some people would suggest that hydroelectric power is the way to counter water loss but, according to the US Geological Survey study, hydro power is actually a huge water user. The report indicates that, on average, a hydro plant will use 1,430 gallons per MW-h…roughly double that of the coal-fired plant.

Although natural gas fired power plants use less water than the Aztec evaporative cooling system there are some economic considerations. According to a 2009 study by the investment banking firm of Lazard, Ltd. a natural gas primary plant generates electricity at the rate of roughly 10.2 cents/kwh. A natural gas peaking plant generates electricity at the rate of roughly 34.2 cents/kwh. A new integrated gasification combined cycle (IGCC) coal plant generates electricity at the rate of roughly 11.0 cents/kwh. The blended electricity rate for an all natural gas utility would be significantly higher than an all coal utility. History also indicates that the cost of electricity from natural gas fired utilities fluctuates more than for coal fired utilities due to the volatility of natural gas prices.

So…do evaporative cooling systems use too much water? When you look at “source energy water use” of power plants versus the local use of an evaporative cooling unit the answer is usually “NO”. And, finally, consider that a local system offers load diversity that the power plant cannot offer, meaning that the local system can be completely shut off, using no water at all when there is no load.

Green Data Center Design Conference Notes

Having just attended the Green Data Center Design Conference in San Francisco I came away with a few observations.

First, although this was a relatively sparsely attended event there were some "heavy hitters" present. Microsoft and eBay both had presentations and representatives in the house, as well as Digital Realty Trust, APC, and Intel. Other members of the audience seemed to include users and providers in the "middle tier" data center class.

It was this "middle tier" that received some attention from APC during their presentation. It was noted that this class of user with facilities in the 2,500 to 10,000 square foot range are not adopting "best practices" as demonstrated by the Microsoft's and Google's of the world. Some of this might be attributed to lower capital budgets but more likely to the slow spread of information about what can be accomplished. PUE numbers in the mid-2s to over 3 can be found in these facilities while large leading edge companies are operating in the mid- to low- 1s.

The term "PUE" itself came under some scrutiny as the right metric for measuring data center performance going forward. Part of this is the thought that other factors ought to be considered such as water usage (the "WUE") but the single biggest reason PUE is being questioned is the massive under-utilization of servers in virtually all data applications. Most of the experts speaking at this conference put utilization factors in the range of 10% to 15%. PUE is calculated based on total installed server capacity...not actual capacity in use. This not only results in PUE numbers that are grossly overstated but also in tremendous wasted capital dollars and far oversized infrastructures such as HVAC.

As for future trends in data centers and large server rooms the consensus also seems to be that "virtualization" will become more commonplace as a means to drive up utilization. "Cloud" services will have the same impact both for public clouds and private, corporate, clouds. This will result in reduced demand for more space for many companies as they begin to use what they have more effectively. Although one presenter suggested that this will cause a dip in construction demand the others seemed to believe that the rapid growth of data consumption will simply outstrip the rate of virtualization and still create demand.

In the cooling/HVAC arena the other trend that was presented by the major players was the rush to "chiller-less" design. Whether this was pure 100% outside air solutions or evaporative cooling solutions the key was to eliminate the chillers, DX equipment, and all of their ancillary equipment costs and complications. Data center specialists from eBay and Microsoft repeatedly pointed out that modern servers are designed to withstand operating temperatures approaching 230 degrees C. The ASHRAE TC 9.9 guidelines just introduced proposed server inlet temperatures of over 110 degrees F for some applications and the most stringent conditions were still around 81 degrees F. eBay commented that their failure rate of components in chiller-less designs is barely greater than in their legacy designs and was more often caused by vibration or software issues than temperature issues. Humidity control was also questioned and an engineering manager for Digital Realty Trust commented that he has seen no problems with relative humidity levels down around 20%. There seemed to be no upper limit that concerned the DRT engineers and they were strongly proposing evaporative ("adiabatic") cooling for their future data centers. Using a system such as the Aztec indirect evaporative cooling system would easily produce temperatures in the ASHRAE guideline range and do so without introducing more moisture into the data center environment.

Green Buildings Get a Boost

ASHRAE has just announced a policy change on the part of the US Army that will give another boost to “green building” design. In October of last year the assistant secretary of the Army for installations, energy and the environment issued a policy memorandum that made ASHRAE Standard 189.1-2009 the baseline design standard for all permanent US Army facilities worldwide. This includes US Army Reserve installations and totals some 954 million square feet of existing buildings.


For those who are not familiar with ASHRAE 189.1 it is the “Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings”. Energy efficiency and monitoring are key elements of the standard. Modern HVAC equipment such as that produced by Applied Air incorporates sophisticated DDC controls that can both improve performance and provide a mechanism for monitoring equipment. Retrofitting of existing Army buildings to improve operating efficiency is an integral part of the Army’s goal of achieving a “net zero” energy profile across the globe.