ASME Paper Documents Reliable Data Center Operation With Outside Air and Evaporative Cooling

One of the longest running and most debated topics regarding data center operation is whether or not you can reliably cool a modern data center using outside air alone or with supplemental evaporative cooling.  If you can successfully operate a data center without using any compressorized equipment there are obviously huge energy and money savings.

The two key factors that hold operators back from implementing an obvious saving strategy is fear of equipment failures due to temperature/humidity excursions and due to airborne contaminants.  While server manufacturers publish data in their specification sheets that clearly indicate that their equipment can tolerate a wide range of temperature and humidity there is not much information regarding the impact of particulates and other contaminants.  ASHRAE has recognized the robustness of modern IT equipment by expanding the recommended and allowable temperature and humidity ranges in their widely followed data center design guidelines.  Very little is said regarding air quality other than a recommendation to use at least a MERV 8 filter system.

Over the last 5 years the Mestex division of Mestek has hosted a National Science Foundation research site at their manufacturing facility in Dallas.  This site is part of an Industry/University Cooperative Research Center with principal research from the Mechanical and Aerospace Engineering Department at the University of Texas at Arlington.  A fully instrumented "data pod" has been operating using a commercially available indirect/direct evaporative cooling system from Mestex that can also operate in 100% fresh air mode.  In addition to the dozen sensors normally included with the Aztec brand IDEC system from Mestex the "pod" includes an array of 64 sensors located on the front and rear of the four server racks.  Data has been streamed from all sensors every 15 seconds for the last 4 years.  In addition to this detailed tracking of temperature and humidity conditions there have been a number of studies conducted using copper and silver coupons to evaluate the corrosion potential of operating using outside air and evaporative cooling.  Keep in mind that this application is in Dallas, Texas...a relatively hot/humid climate area.  In addition, because the "pod" is installed between two manufacturing buildings in an industrial zone near downtown Dallas the measured air quality around the "pod" is classified as G2, or moderately harmful to PCBs.

The June, 2017 Volume 139 edition of the ASME Journal of Electronic Packaging includes a paper presenting the results of the last 4 years of the research at this site.  The paper entitled "Qualitative Study of Cumulative Corrosion Damage of Information Technology Equipment in a Data Center Utilizing Air-Side Economizer Operating in Recommended and Expanded ASHRAE Envelope" provides a comprehensive look at the impact of operating a data center in a "real world" application.

The most interesting point presented in the summary section of the paper is that, in spite of the servers installed in this test site already being several years old, there has not been a single server failure in the entire four years of operation.  The ability to dramatically reduce the cost of operating a data center...without unfounded concerns about finally being proven true.

Cool New Technology for Mestex from AHR 2017

New Graphics Tool Allows Users to "See Inside" Mestex Products.

As I mentioned in my last blog entry Mestex participated in the 2017 AHR Expo last week in Vegas.  As usual we were part of the much larger Mestek corporate display showing the industry just how broad our company's product offering can be.

One challenge with such a broad offering is that it can be difficult to explain to potential customers, and even our own reps and employees, how much of the equipment actually works.  This is true even within the Mestex division as our products cover everything from air handlers to fully packaged DOAS units, and from advanced evaporative cooling systems to steam integral face and bypass coils.

In the photo to the right you can see a demonstration of the latest corporate sales tool that helps cut through some of the mystery.

The Mestek Technologies group has developed an interactive, graphical software app that reps can use to help illustrate some of the more complicated products from the Mestex division.  This app allows the user to select from the Aztec Indirect/Direct evap system, the IFL air handling system, or the FAP packaged DOAS-capable rooftop unit.  Once selected a screen opens that shows the user the elements of the unit that can be selected for configuring a product to meet their needs.  Touching any of the components, or the complete unit illustration, will open that component and by using the "pinch-zoom" function of touchscreen devices the user can "open up" the product and drill down to detailed images of the unit.  Buttons to the right allow the user to "turn on" heating, cooling, dampers, etc and watch how the airflow in the unit changes.

Using the app at the show pointed out how clear our configurable product concept became to viewers.  It was immediately obvious that the products shown had great flexibility and adaptability to suit their application.

The app is now available on the Google Play store for download to compatible devices by searching for "Mestek" and then looking for the "Mestex" icon in that storefront.  A version for iOS devices will be coming from the Apple store in the near future.

While this app proved to be an exciting tool to the reps that saw it there is much more to expect from the app going forward.  New products will be added.  Links to technical and sales literature will be added.  Embedded videos will be added.  Integrated CFD models will be added. 

Basically, this will become the most powerful "catalog" available for Mestex products.

On The Road Again

To quote one of my favorite musicians, Willie Nelson, we are going ..."On the road again, just can't wait to get on the road again..." this time to Las Vegas for the 2017 AHR Expo

The Mestex division of Mestek will be sharing booth space with our sister companies in booth C1525 in the Las Vegas Convention Center.  Some people are predicting a record turnout of attendees and we expect a busy few days.

This year, Mestex will be using some new (for us) graphical display technology from the Mestek Technology group to help explain some of our newer product offerings.  Our division companies; Applied Air, Aztec, Alton, LJ Wing, Temprite, and King provide solutions to temperature, pressure, airflow, and filtration problems that can be hard to explain using a static piece of equipment.  This graphical display technology will allow us to "walk you in" to three of our products and highlight how certain elements of the products can be used to address your building or process issues.

In addition to these graphics the Mestex people in the booth can explain how our in house CFD analysis services can help optimize a solution.  Projects ranging from large e-commerce warehouses and distribution centers to data centers to "indoor agriculture" grow rooms can be very difficult to design due to high internal thermal loads, humidity levels, stratification, or pressure gradients and CFD allows Mestex to thoroughly analyze and sort out possible solutions.

So come on by the booth and, at least, say "hi".  We would love to discuss how we might help solve your application problems.

Helping to Solve Future Demands for Food has been a long, long time since I have posted anything on the blog.  Time flies by at times and it is easy to lose track of the months since the last posting.  However, I am back :-) and will become more diligent in sharing my thoughts with you.

In the last couple of months I have participated in two unique meetings organized by "the Vertical Exchange" folks.  One of the meetings focused on the food industry and the other focused on design/build contractors.  Mestex is  such a diverse division of Mestek that we have solutions for projects in both of those segments...among many others.  There was an overlap between those two markets that might not, at first, seem obvious.

Increasing population densities in many parts of the world combined with changing climates is beginning to impact the ability of food companies to grow quality produce in the volumes needed.  There is also the specialized "boutique" grower who supports the "farm to table" concept in urban environments.  A solution to these scenarios that is emerging is the world of "indoor agriculture".  This goes well beyond traditional greenhouse facilities.  Indoor farms use sophisticated lighting, watering, and nutrient systems to grow produce 24/7/365 in controlled environments.  These facilities can be single story purpose built buildings, multi-story repurposed commercial buildings, or even "modular" buildings similar to modular data centers.  With the exception of the modular solutions all of these projects require the talents of design/build contractors for proper execution.  Even the modular solutions that are "factory built" still require qualified on-site contracting for completion of the project.

From a mechanical design point of view these facilities can be quite challenging.  In order to create an artificial environment for growing plants the power demands of the lights used to create an "artificial sun" will create very high thermal loads.  The watering and transpiration of the plants creates high latent loads on the HVAC equipment.  Providing the necessary CO2 without creating a hazard for employees is also important and, finally, preventing the introduction of pests and unwanted biological hazards requires very high levels of filtration.

In short....the HVAC systems must be able to handle very high sensible loads, very high latent loads, very high filter densities, and include controls that can flush a grow space quickly and efficiently...preferably all in one package!  No small task.

Mestex has had decades of experience providing equipment to the food industry and to design/build contractors.  We are leveraging that experience to develop solutions to the problem of indoor agriculture.  One of the first areas where we are working is in the world of cannabis growing.  This market is unique in that the revenue stream and profits are large enough to justify development of an advanced HVAC solution that accomplishes all of the needed functions in a single package.  The lessons learned in that market will transfer to more cost sensitive indoor agriculture products that can help meet the demands of those markets as well.

For more information about some of the work being done by Mestex you can refer to a couple of articles that were published by Business News Publishing for the 2016 Mechanical Exchange.  This link ( will take you to the eblast site where you can open the entire Air Conditioning News supplement.

"We Have A Failure To Communicate"

For the last 15 years the Mestex division of Mestek has been building direct digital controls ("DDC") into our equipment.  We started with some pretty simple control programs on some of our more basic units.  Even these simple programs allowed the equipment to operate more effectively...controlling temperature more closely, controlling energy consumption better, and giving users more options for scheduling their system operation.

The core functions of our control systems have not changed much over the years but the features that have been added, and are continuing to be added, to improve the information available from our equipment are almost mind-boggling. 

Take the relatively simple technology of evaporative cooling.  The Mestex Aztec indirect-direct evaporative cooling unit comes standard with a DDC control package that constantly monitors outside air conditions, unit supply air conditions, unit water quality, and cooled space conditions in order to control temperature, pressure, and humidity in the space.  But that is only part of the story.

While collecting all of the data we just described and deciding how to control the unit functions the DDC processor is also collecting, and making available, a wealth of other information.  The unit can provide real time electrical power consumption and demand, real time water consumption, and constantly updated information about the operating mode of the equipment (operating hours in full economizer mode, operating hours in full recirculation mode, and operating hours in mixed mode).  The unit is also accumulating and can display daily, monthly, and annual power and water use data.

This is obviously some pretty sophisticated information from a relatively simple machine.  The same algorithms used in this unit can be applied to most of the other Mestex products and provide a wealth of management information to end users.  The larger the end user organization and the more units deployed, the more valuable this information becomes. 

But...the information is only valuable if management can actually see it.  As more and more of our equipment installations are tied to building automation or building information systems we are encountering more and more interface issues.  The issues are not matters of communication protocols since our DDC packages are designed to speak virtually every communication language but issues of human communication protocols.

What we have found in many cases is that the information, and the interface to the equipment, is turned over to an IT person who is unfamiliar with HVAC equipment.  That person is probably also very concerned about network security and has probably created firewalls that make implementation challenging.  The HVAC equipment might be working perfectly but the person on the other end who is looking at data that he does not understand will frequently interpret that the equipment is not performing as required.

So, as is often the case in life, training and communication become essential to success.  As an HVAC company we usually expect the IT person to "simply understand".  I think, however, that we should work hard to learn about networking and IT issues so that we can at least speak the same language as the person on the other end of our equipment.


Over the years that I have been at Mestex I have marveled at how well we have been able to control our warranty expenses.  Having come from one of the large HVAC product manufacturers where it was not uncommon to have warranty expense at 3 to 4 percent of sales our average of less than 1 percent of sales is extraordinary.

Of course, this level of product quality does not happen by accident.  Selecting components that are designed for long life, using material gauges that are one grade heavier than most competitors, constructing many products with welded steel frameworks... all contribute to products that are designed to last.  But a great design can fall down at the production level so we have also implemented laser alignment systems, rotating component balancing systems, multi-point functional testing of every product that leaves the building, and compliance with all industry standards for safety.  We are confident that when a product leaves our building that it has been built to a high standard for longevity, service, and efficiency.

But there are standards outside of our normal industry standards that can improve our quality beyond even the product itself.  One of those internationally recognized standards is, of course, ISO 9001.  Reaching into all elements of our business and documenting how we do things in an effort to make all phases of the business better is an expected result of attaining an ISO certification.  Mestex is proud to announce that we have now received such a certification and we are now an ISO 9001-2008 certificate holder. (Certificate No.: TRC 00937 issued to Mestex, Dallas)

We don't intend to stop there however and we have already started work on attaining an ISO 14001 certification.  This process is targeted at our environmental practices and policies.  Although Mestex has taken major steps over the last few years to reduce our environmental impact we believe that there is more that we can do and that is our next target.

Relative Humidity – It’s all relative

A Guest Article by Jim Jagers

The other day I was conducting a training class, and we were discussing evaporative cooling. Someone said they didn’t think evaporative cooling would work very well in their area because the summer temperatures were 90°F plus with 90% RH. If you were to look at many psychrometric charts, you’d see this point is, dare I say it, “off the chart”. To get a feel for this consider a steam room has general temperature of 104°F and 100%RH. At 90°F with 90% RH the heat index is 122°F. It’s doubtful the temperature and humidity are as bad at the same time as he imagined.

People generally associate high temperatures with high humidity percentages. It’s more likely that high temperatures will be associated with lower humidity percentages. At 80°F and 41%RH the heat index is 80°F. 80 degrees feels like 80 degrees. At this point there is approximately 0.009 pounds of moisture per pound of dry air in the atmosphere. If the moisture content remained constant and the air warmed to say 90°F, the relative humidity would actually drop to about 30%. Conversely, if the moisture content remained constant and the temperature dropped to 70°F, the relative humidity would increase to about 57%. This is because cooler air can hold less moisture than warmer air, and relative humidity is the ratio of the moisture in the air compared to the amount of moisture the air (at a specific temperature) can hold expressed as a percentage.

People usually think of their air conditioner as providing cool dry air in the summer, and it does because it does both sensible and latent cooling. Sensible cooling lowers the temperature we sense, and latent cooling removes the moisture. The air entering the coil may be 78°F and have 0.0101lbs of moisture per pound of dry air. The coil temperature may be 45°F and thus the leaving air may be 60°F (It won’t be 45°F because the water in the air is absorbing some of the cold). At this point the leaving air may have a moisture content of 0.0062lbs per pound of dry air. This is a significant reduction in moisture, and it is evidenced you water dripping from the evaporator coil. The leaving air is much dryer than the entering air.

However, in relative terms the air coming off the evaporator coil in the air handler has a relative humidity of 100% or close to it. Remember, cool air can’t hold as much water as warm air. When the air entering the coil, contacts the cold fins it cools rapidly. Condensation occurs when air can’t hold the moisture it contains. At this point the air is fully saturated meaning its relative humidity is 100%.

The point to this brief essay is, as I said at the start, relative humidity is all relative - to the moisture in the air and the air temperature. Warm air isn’t necessarily humid; cool air isn’t necessarily dry, relatively speaking.

A History of Innovation

Mestek is an extremely broad and diversified HVAC/Architectural products company.  While that makes our products some of the most widely used in the construction industry we face an interesting problem.... very few people have heard of us.  Since the company goes to market with the individual brand names manufactured by our various divisions the name "Mestek" is pretty much unknown.

Many of the brands that make up the Mestek family have long histories in the HVAC business.  One of those brands is produced in Dallas and is known as "LJ Wing".  We recently did a little digging in our archives and came across a brief history of the brand that I want to share. 

The LJ Wing company actually started with the inventions of Mr. Levi Wing back in 1875.  Yes, that date is correct...1875!  As early as 1878 Wing was starting to receive awards for designs of products such as a ventilation fan. In 1902 the company was officially incorporated as the LJ Wing Manufacturing Company and that company name stayed unchanged for the next 63 years.  Through a series of sales and acquisitions LJ Wing finally became a part of Mestek in 1987.

Looking back through the history of Wing highlighted how innovative the company has been over the past 100 plus years.

  • Wing is believed to be the originator of gas engine power for marine applications.  Your current outboard motor was spawned from that idea decades ago.
  • Wing received a number of awards from 1878 through 1893 for design and development of a ventilation fan known at the time as a "disc fan"... basically a precursor to today's "propeller" fans.
  • One of the other significant innovations that was part of the development of the disc fan was the integration an electric, steam, or gas-powered motor to drive the fan.
  • Following along this line of integrating unique, for the time, drive systems 1907 saw Wing introduce a turbine-driven forced draft blower for the power plant industry.
  • In 1917 Wing introduced marine versions of its propeller fans to the US Navy.  This design ended up installed on over 200 US Navy destroyers over the next couple of years and, eventually, on almost 80% of the fleet.
  • 1920 saw the first product that would eventually become part of today's product line...a lightweight, overhead mounted, unit heater with hydronic coil.
  • In the late '20s Wing introduced what we know today as "door heaters".
  • In the late '30s a core product of today's company was introduced... the integral face and bypass coil.  Originally in a vertical configuration the same basic coil design is available today in both vertical and horizontal configurations.
  • Also in the late '30s Wing introduced an axial flow blower system to industry and the navy.
  • Another unique, and still produced today, product developed in 1935 was the revolving discharge that allows unit heaters to spread heat over broad areas by slowly spinning the discharge openings through 360 degrees of rotation.

Over the next 90 years Wing products were refined and modified for better performance and reliability.  Then, in 2014, Wing products that have integrated fans and housings were upgraded with optional DDC controls that not only control unit operation but allow the LJ Wing products to be integrated into a building automation system or accessed remotely via the Internet.

LJ Wing clearly has a history of innovation and a history that has survived all of the major economic downturns.  Engineers, contractors, and owners who specify or purchase LJ Wing products can obviously have confidence that the company will be there to support them. 

Wing is just one of the many brands produced in Dallas by the Mestex division of Mestek and the common theme for all of those brands is innovation, stability, and longevity.

Why Do We Design Thermos Bottles?

Over the last couple of months since my last posting I have been very busy managing our movement into new markets and grasping at new opportunities.  One of the benefits of taking the deep dive into these markets is getting to look at some of the details of product design and application to the specific problem to be solved. 

This has raised a question in my mind.

Why does the mission critical industry design "thermos bottles" and then fret over the cost of and methods of getting rid of the heat that all those servers generate? 

There is something that strikes me as illogical about creating buildings or modular data centers with super insulated walls and ceilings that are guaranteed to trap the heat that is dumped into the hot aisle (assuming they have aisle separation).  Then the mechanical system is tasked with rejecting all of the pent up energy without costing the owner a fortune.  Is it any wonder that data centers are one of the largest consumers of electrical energy in the world?

Centuries ago architects and designers figured out that it is more efficient to cool a space if you simply dump the heat out to the atmosphere.  Buildings used to be designed to take advantage of stratification and stack effect to cause the hot air generated in the space to rise and leave the building.  No need to cool the air back down to a reasonable temperature and put it back into the space so that you can heat it all up again.  Lofted ceilings and roof lines came into the design world for a reason. 

So, why is the data center different?  Frankly, I don't know.  Why not take the hot aisle air and vent it out to the atmosphere?  Sure, you have to replace that exhausted air with new air from the outside but unless the data center is located in Death Valley the odds are that the air being brought into the building is at a lower temperature than the air that would be recycled from the hot aisle of a data center designed to operate under the latest ASHRAE TC 9.9 guidelines for best practices. 

My best guess why we continue to do what is intuitively illogical is inertia.  "We have always done it that way".  I think it is time to rethink the old ways and come up with creative solutions in the design of data centers.

Mestex and the National Science Foundation Advisors Meet in Dallas

Although it has been far too long since I have posted to this blog due to my travel schedule I have some news to share.

Over the last few days (Oct. 1 & 2) we have been participating in the Industry Advisory Board ("IAB") meeting of the NSF-I/UCRC ES2 ("National Science Foundation-Industry/University Cooperative Research Centers Energy Smart Electronic Systems") research consortium.  That mouthful of letters represents a group of universities and companies whose expressed goal is to reduce the energy consumption of data centers by 20-35%.

The consortium is currently working on fourteen research projects and Mestex serves as an advisor ("mentor") on three of those projects.  Two of the projects that Mestex is mentoring cover research on evaporative and fresh air cooling of data centers and a second project on contaminants in data centers that use fresh air cooling.  As you might guess, the project on evaporative and fresh air cooling offers the greatest opportunity for the consortium to reach the stated goals.  In order to support that research, Mestex has installed a small data pod at it's facility in Dallas and is cooling that data pod with a commercially available Aztec ASC-5 unit.  The ASC-5 has built-in DDC controls that facilitate the use of multiple temperature and humidity sensors for control without any special modifications.  The controls also include a provision for pressure sensing control and that is also implemented in this case.

In addition to the data that is presented by the standard Aztec DDC controls there are additional thermocouples and sensors installed that are streaming data to researchers at the University of Texas at Arlington.

One of the most critical considerations that prevents many data center operators from reducing their energy consumption by huge amounts is the reluctance to introduce outside air to the facility.  The second Mestex project is focused on that research and we were fortunate to have the input of one of the world's experts on contamination control provide test coupons and laboratory analysis of the results.  Dr. Prabjit "PJ" Singh, of IBM, provides guidance and analysis to companies around the world and is a major source of information for the ASHRAE TC 9.9 committee on data center cooling.  Dr. Singh, Dr. Dereje Agonafer from the University of Texas at Arlington, and several members of the NSF IAB toured the Mestex facility at the conclusion of the meetings this week. 

Drs. Singh and Agonafer are shown here learning about the technology behind the patented "Digital High Turndown Burner" that was developed at Mestex.  Jim Jagers, Mestex Sales Manager,  conducted the tour and provided a "deep dive" into how this unique technology works before the group proceeded to the research data pod for additional discussions.