Increased Temps = Time For A Cabinet Cooler

This past Monday, we kicked off the start to the new Spring season, which means warmer temperatures are in the forecast. Here in Cincinnati, we are expecting temps in the low 40’s up to the high 60’s. We’ve written a couple blogs in the past few weeks about the changes in temps and weather and the proverbial “spring cleaning” and the use of our Vacuum Systems for industrial cleanup.

Another area of concern relating to the increased temps is the overheating and contamination of electrical control panels in industrial environments. As the temperatures go up, many companies are looking for a fast solution and will open the doors on the panel and use a fan to blow air across the sensitive controls. While this method does provide some cooling and seems like a quick fix, you are also introducing dirty, potentially humid air into the enclosure which can result in failures and lost production.  Not to mention, this is an OSHA violation which can lead to potential injury to operators  and/or costly fines.

What seems like a simple fix is actually a BAD idea!

EXAIR’s Cabinet Coolers are a reliable, maintenance free way to keep electrical enclosures cool, dry and clean. The Cabinet Coolers are compressed air operated, with cooling capacities ranging from 275 Btu/hr. up to our largest Dual System of 5,600 Btu/hr. The units discharge the cold air into the cabinet at a slight positive pressure which expels the hot, dirty air, leaving only the cool, clean, dry air from the system. Systems are available for continuous operation, maintaining a 45% relative humidity on a completely sealed cabinet, ensuring no condensation develops inside the cabinet. Our Thermostat Controlled Systems are available in 120VAC, 240VAC or 24VDC, providing a more economical operation by only using compressed air when needed to reach the desired temperature set point. Our thermostats are preset at the factory to 95°F but are adjustable to meet your specific temperature requirement.

How the EXAIR Cabinet Cooler System Works

In order to properly recommend a unit, we need to know the internal heat load of the cabinet or watt loss of the controls inside. We realize this information is sometimes not readily available, so to help simplify the process, we have a Sizing Guide available, which provides the pertinent information requited to calculate the current load. Of course, you can always give us a call and an application engineer can help you over the phone as well.

Cabinet Cooler Sizing Guide

 

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

Not a Fan of Fans Because Rising Air Temp Will Kill Your Electronics

Using a fan is a popular method for machine builders to provide cooling for an electrical enclosure.  The electrical panel stays cool for machine acceptance at the factory, and possibly for even the first 6-8 months of operation and then one day, there is a problem, and the machine shuts down due to an over heated component within the panel. This leads to opening up the panel, possibly placing an external fan, and operation of the machine in an unsafe condition, to meet the daily production needs.  What has led to this situation?  Summertime!

To better understand the situation, let’s review the heat formula.  The total heat content of air consists of the sensible and latent heat factors. Latent heat is the heat that is required to change the state of a material, say from liquid to solid.  Water to ice is an easy way to understand this type of heat.  When heat is removed from water at 32°F it turns to ice at 32°F.  There is no temperature change, but heat has been removed. Sensible heat is dry heat, it is a result in change of temperature, but not change in state or moisture.  For fan cooling, the air and moisture only change temperature and not state, we can focus on the sensible heat portion.

In English units:  Q = Cp x ρ x q x ΔT x 60 min/hr

And for air:

Q –  is the sensible heat flow in BTU/hr

Cp – is the specific heat in BTU/lb °F – 0.2388 BTU/lb °F

ρ – is the air density at standard conditions – 0.075 lb/ft3

q – is measured air flow in ft3/min – CFM

ΔT – is the temperature difference in °F – Final Air Temperature – Starting Air Temperature

Plugging in the constant values, gives us:

Q = 1.0746 x CFM x ΔT

It is common to chart the above formula for various ΔT values, plotting Q vs. CFM values on a dual logarithmic scale, as shown below-

BTU-CFMGraph4

As an example, for an internal heat load of 1300 BTU/hr, to ensure that the temperature rise (from ambient) in the cabinet does not exceed 20°F, 60.5 CFM of air flow is required (the red line above).  A fan with this CFM rating is specified and installed in the panel.

This works  when the ambient temperature is a comfortable 75°F, in a climate controlled factory, or the cooler months of the year.  The problem occurs when the ambient temperature increases to 95°, 100°, or even 105°F,  not uncommon in the summer, and in plants that create large amount of heat, like metal production, and near boiler systems and furnaces.  Under these conditions, the fan will still maintain the 20°F difference, but the internal temperature of the cabinet will rise to 115°-125°F, temperatures where electrical components start to fail or shut down.  The solution to this issue?  Lower the Starting Air Temperature.

The EXAIR Cabinet Cooler Systems use our Vortex Tube technology to take compressed air and provide a cold flow of air that enters the enclosure at 5o°F less than the compressed air temperature.  With a compressed air temperature of 70°F, common for industrial compressed air systems, the Cabinet Cooler will deliver cold air at 20°F.  Again using the chart above, flowing just 20 SCFM of this air will absorb the 1300 BTU/hr of heat (the green line), and result in an internal air temperature 80°F no matter the ambient air temperature.  The electronics in this enclosure will run trouble free, for a long time. This ambient air temperature problem is also true of air-to-air heat exchangers, as the ambient air temperature rises the ability to remove heat diminishes.

Another consideration, the fan system is bringing in air from the surroundings, which is hot and dirty, passing it through a filter (which gets clogged, reduces air flow, and needs to be replaced.) The Cabinet Cooler System, includes an automatic drain filter separator, which filters the compressed air to be free of dirt, dust and moisture. The air entering the enclosure is cool, dry and fee of dust and debris.

ETC CC

NEMA 4 Cabinet Cooler System with Optional Electronic Temperature Control

To discuss your application and how the EXAIR Cabinet Cooler System can be a benefit at your facility, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Twitter: @EXAIR_BB

 

EXAIR Cabinet Cooler System Meets High Demands Of Sea Duty

I joined the Navy, right after high school, to get out of Ohio, see the world, and never come back. “My recruiter said” (if you are considering military service, those can be famous last words, just so you know) that I would be a good candidate for Nuclear Power School, so I took the test. As a math & science nerd scholar, I qualified for admission easily.  About halfway through Nuke School, I volunteered for submarines.  My decision was based in no small part on the sea stories of our instructors, the strong reputation of better food, and my deep appreciation for the movie “Operation Petticoat.”

Upon graduation, I was assigned to a new construction Trident submarine.  I did not see the world…I saw the Electric Boat shipyard in Groton, Connecticut, and Naval Submarine Base King’s Bay, Georgia.  Hilarity occasionally ensued, but never in the context of that movie I so adored.  I moved back to Ohio (on purpose) soon after my enlistment was up.  The food WAS good…I can unreservedly vouch for that.

In the new construction environment of the shipyard, I became quite familiar, and developed a deep respect for, the high level of attention paid to the materials and workmanship that a seagoing vessel demanded…not to mention, one with a nuclear reactor on board.  Reliability and durability are obviously key factors.

I had the pleasure recently of assisting an electrical contractor who was looking for a cooling solution for a new Variable Frequency Drive enclosure installation on a cement barge.  The ship’s engineer (a Navy veteran himself) had told the contractor that his priorities were reliability, durability, and dust exclusion.  He couldn’t have made a better case for an EXAIR Cabinet Cooling System.

Based on the specified heat load of the VFD, the size of the enclosure, and its location, a Model 4380 Thermostat Controlled NEMA 12 Cabinet Cooler System, rated at 5,600 Btu/hr, was specified.  This equipment is internal to the ship; had it been exposed to the elements, a NEMA 4X system would have been presented.

Up to 2,800 Btu/hr cooling capacity with a single Cabinet Cooler System (left) or as much as 5,600 Btu/hr with a Dual system (right.)

EXAIR Cabinet Cooler Systems have no moving parts to wear, no electric motor to burn out, and no heat transfer surfaces (like a refrigerant-based unit’s fins & tubes) to foul.  Once it’s properly installed on a sealed enclosure, the internal components never see anything but cold, clean air.

If you have a need to protect an electrical enclosure in aggressive environment, give me a call.  With a wide range of Cabinet Cooler Systems to meet a variety of needs, we’ve got the one you’re looking for, in stock and ready to ship.

Russ Bowman
Application Engineer
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Video Blog – Installing an EXAIR NEMA 4/4X Cabinet Cooler

Installing an EXAIR Cabinet Cooler is fast and easy.  Watch the video below to see what it takes to install an EXAIR NEMA 4/4X Cabinet Cooler.  And, for a video showing how to install the Cold Air Distribution Kit after the Cabinet Cooler is installed, click here.

If you have any questions about our products, feel free to call an Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

 

Thanks to Bensound for the royalty free music in this video!

Video Blog: Assembling the Dual Cabinet Cooler Hardware Kit

Dual Cabinet Cooler Systems consist of two Cabinet Coolers and a model 4908 Dual Cabinet Cooler Hardware Kit.  This hardware kit will connect the Cabinet Coolers together for a single compressed air supply port. This video shows you how to assemble the hardware kit to the Cabinet Coolers, and then illustrates installing the Dual Cabinet Cooler System on an enclosure.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

 

EXAIR Cabinet Cooler in Bahrain Still Operating Years Later, In Harsh Conditions

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This small NEMA 12 type Cabinet Cooler has been in operation for years. Now, two additional units are needed for new applications.

A few weeks ago I was contacted by a mechanical contractor in Bahrain about a needed Cabinet Cooler.  Their customer had an existing unit in place and needed two more for similar applications.  As with any Cabinet Cooler need, we needed to start with an accurate understanding of the heat load involved, to make sure we recommend the proper model number.

So, we used the Cabinet Cooler Sizing Guide to gather the required information and calculate the heat load of the application.  After using this information to calculate a heat load of 426 BTU/hr. (~125W), we confirmed that the existing model 4308-240 will be the correct fit for the additional cabinets as well.

img-20170111-wa0000

Even in this dirty environment the Cabinet Cooler continues to function.

The existing Cabinet Cooler has been in operation for several years without any required maintenance or upkeep.  Clean compressed air, achieved with a simple 5 micron water/dirt filter separator,  is supplied to the unit and nothing but clean cold air is fed into the cabinet.  Relative humidity is regulated by the Cabinet Cooler to 45% resulting in stable temperatures and humidity for the electronics inside the enclosure.

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The dirt and debris are prevented from entering the enclosure due to the design of the Cabinet Cooler. Only clean, cold air enters the cabinet. Hot air is vented away.

This application is an excellent example of the durability of EXAIR products.  With proper compressed air supply our products will operate uninterrupted and at proper performance for years.  If you’re in need of a durable solution for an electrical enclosure, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

You Might be Freezing, but Your Electronics Can Still Overheat

For those of us in the Northern Hemisphere it can be easy to be overrun by static elimination problems during these winter months.  But, colder outside temperatures don’t always mean cooler temperatures for the electronics used in production processes.

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This cabinet was facing unaddressed overheating issues before exploring a Cabinet Cooler solution

I received an email from one of our distributors this week describing two applications with failing electronics (shown above and below).  The root cause of failure for both applications was excessive heat inside the enclosures which house electronic devices, even though the ambient air temperatures weren’t abnormally high.  So, we used the Cabinet Cooler Sizing Guide to determine the heat load of each application and make recommendations for proper Cabinet Cooler model numbers.

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This cabinet was also overheating, causing problems in the processes controlled by the components inside the cabinet.

What we found was that the heat load in both cases was rather low, but in each case it was enough to cause the electronics to overheat.  When the temperature of the electronic devices exceeds their specified temperature range, they cease to operate, causing downtime of every device tied to the processes they control.  By installing a Cabinet Cooler onto each enclosure, the overheating problem will be quickly and easily solved.  And, because of the relatively low heat load in this application, a small NEMA 12 type Cabinet Cooler was the perfect solution.

If you have an overheating electrical enclosure, whether during the Winter, Spring, Summer, or Fall, contact an EXAIR Application Engineer.  We’ll be happy to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE

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