Tag: enclosure cooling calculator

The Vortex Tube, Maxwell’s Demon, Hilsch Tube, Ranque Tube: What Exactly is this Device? How Does it Work?

Published on by Tyler DanielLeave a comment

If I were to tell you that I can take a supply of ordinary compressed air and drop its temperature by 50°F with no moving parts and without any type of refrigerant or electrical connection, you might be scratching your head a bit. That is of course unless you’ve been introduced to the wild world of Vortex Tubes. My favorite product among the EXAIR Product Line, the Vortex Tube, does just that. With an ordinary supply of compressed air as the sole power source, and no moving parts, the Vortex Tube converts that airstream into a hot and cold flow that exits from opposite ends of the tube. No magic, witchcraft, or wizardry involved here. Just physics!

The theory all began in the 19th century with the famous physicist and mathematician James Clerk Maxwell. He suggested that since heat involves the movement of molecules, it could be possible to create a device that could distribute hot and cold air with no moving parts with the help of a “friendly little demon” that would sort and separate the hot and cold molecules of air. Not much was done with regard to this or any further advancement until about 61 years later.

In 1928, a French physics student by the name of George Ranque was conducting some testing on a vortex-type pump he had developed. In this testing, he noticed that warm air was exhausting from one end, while cold air was coming out of the other. He dropped his plans for the pump and begin an attempt to exploit this phenomenon commercially. His business ultimately failed, along with the Vortex Tube theory, until 1945 when a German physicist named Rudolph Hilsch published a scientific paper based on the Vortex Tube.

With so many involved, the tube became known by a variety of different names: “Ranque Vortex Tube”, the “Hilsch Tube”, the “Ranque-Hilsch Tube”, and (my personal favorite) “Maxwell’s Demon”. Over the years, it has gained a reputation as a low cost, reliable, and highly effective method for industrial spot cooling and panel cooling applications. While using the tube as a PC cooler isn’t generally recommended, here’s a great video demonstrating the tube in operation from Linus Tech Tips on YouTube:

So how exactly does this thing work? The truth is no one knows for certain, but there is one commonly accepted theory that explains the phenomenon:

Compressed air is supplied into the tube where it passes through a set of nozzles that are tangent to the internal counterbore. The design of the nozzles force the air to spin in a vortex motion at speeds up to 1,000,000 RPM. The spinning air turns 90° where a valve at one end allows some of the warmed air to escape. What does not escape, heads back down the tube in the inner stream where it loses heat and exhausts through the other end as cold air.

Both streams rotate in the same direction and at the same angular velocity. Due to the principle of conservation of angular momentum, the rotational speed of the inner vortex should increase. However that’s not the case with the Vortex Tube. The best way to illustrate this is in Olympic Figure Skating. As the skater is wider, the spinning motion is much slower. As she decreases her overall radius, the velocity picks up dramatically and she spins much quicker. In a Vortex Tube, the speed of the inner vortex remains the same as it has lost angular momentum. The energy that is lost in this process is given off in the form of heat that has exhausted from the hot side of the tube. This loss of heat allows the inner vortex to be cooled, where it can be ducted and applied for a variety of industrial applications.

This Vortex Tube theory is utilized in basic Vortex Tubes, along with a variety of other products that have additional features specific for your application. EXAIR’s line of Cabinet Coolers, Cold Guns, Adjustable Spot Coolers, Mini Coolers, and Vortex Tubes all operate off of this same principle.

If you’re fascinated by this product and want to give it a try, EXAIR offers an unconditional 30 day guarantee. We have them all in stock and ready to ship as well, same day with an order received by 2:00 ET. Feel free to get in contact with us if you’d like to discuss how a vortex-based product could help you in your processes.

Tyler Daniel, CCASS

Application Engineer
E-mail: TylerDaniel@EXAIR.com
Twitter: @EXAIR_TD

Cabinet Coolers: How to Determine Heat Loads

Published on by johnball2014Leave a comment

As summer continues, electrical panels will continue to overheat and cause problems within your process lines.  Freon-based coolers can be less effective in higher ambient conditions; and opening the electrical panels to have a fan blow inside creates a dangerous hazard.  The electrical industry states that for every 10oC rise above the operational temperature, the life of an electrical component is cut in half.  To reduce loss in production and premature equipment failures, it is important to keep electrical components cool.  The EXAIR Cabinet Cooler Systems are designed to do just that. 

From right to left: Small NEMA 12, Large NEMA 12, Large NEMA 4X

To find the correct type and size, we need some information about your electrical panel.  EXAIR makes it easy with the Cabinet Cooler Sizing Guide.  This sheet goes over the important details to find heat loads, proper NEMA type, and options for easy installation.  With a filled-out form, we can make sure that the correct model is recommended.  First, we have to start with the surface area of the electrical panel.  From here, we can do some heat load calculations to compare it with the proper cooling capacity. 

To properly reduce the temperature internally, we need to calculate how much heat is being generated.  Heat loads come from four main areas; internal, external, fan, and solar.  From these four, we can add them together to get the total heat load.  So, on the hottest day of the hottest month, the EXAIR Cabinet Cooler System will still keep your electronics cool.  Here are some methods to find the information needed for heat load calculations.

Internal Heat Load:  The internal load is the heat generated from inside the electrical panel.  This heat is produced from the inefficiencies of electrical devices.  There are two ways that we can figure out the internal heat load.

Step A: The simplest way is by hanging a piece of metal like a washer inside the panel for about 15 minutes.  We can get an average temperature inside.  In the sizing guide, you can mark the temperature next to “Internal temperature now”.  To calculate the heat load, we will need the external temperature at the same time you measured the piece of metal.  This temperature difference can determine the internal heat load per surface area of the panel.  See the chart below.

Step B:  if you know the electrical components inside that generate heat, a list can be made with volt/amp ratings, or watts.  This is very useful for new panels.  The major devices would be VFD (Variable Frequency Drives), power supplies, UPS, transformers, thyristors, etc.  We can calculate the inefficiency of the electrical components which will give us the internal heat load.

External Heat Load:  To keep the electronics cool on the hottest day, we will need to know the highest external temperature that the panel will see.  This can include the temperature that is near an oven.  This can be marked in the Max External Air Temperature Possible.  We can compare this to the Max Internal Air Temperature Desired.  Most electrical components are designed to operate at 95oF (35oC).   With the same chart as above, you can use the temperature difference to determine the external heat load per surface area of the panel.

Panel Fans:  To control the environment inside the electrical panels, we need to block all openings and vents.  And this will include removing panel fans if they are installed.  The Cabinet Cooler System will blow dry cold air to push out the hot humid air from the electrical panel back through the Cabinet Cooler.  Since we are removing a “poor” cooling device, we still need to add this to the heat that is being removed.  You can either give the diameter of the fan or the flow of the fan. 

Solar Heat Load:  The solar heat is only needed if the panel is located outside without cover and exposed to sunlight.  For this type of heat load, we will need to know the color of the electrical panel.  Lighter colors will not absorb as much heat as darker colors.

Because there is so much information that is critical for proper sizing, EXAIR also created a Cabinet Cooler System Calculator to give you a good recommendation to keep your electronics cool. I gave some examples above on how to find the heat loads.  Electrical shutdowns are expensive and annoying.  If you have interruptions from high internal temperatures, EXAIR Cabinet Coolers are a great solution.  They can be installed quickly and easily.  With no moving parts or costly preventative maintenance needed, they can run for decades in keeping your electronics cool.  For our U.S. and Canadian customers, you will receive an AC Sensor for free, a $65.00 value, as a promotional item from now until the end of August 2022 with qualified purchases.  How can you not give them a try?  If you have any questions about Cabinet Coolers or the Sizing Guide, you can contact an Application Engineer at EXAIR.  We will be happy to help.

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

Hazardous Location Cabinet Cooler Systems “Make Things Better”

Published on by Russ BowmanLeave a comment

In a previous arc in my career path, I worked on, and then built, and then sold industrial pumps, so I’ve been in my fair share of chemical plants. Did you ever wonder what all these places make? A decent number of them make what are called “intermediates”. These are compounds, solutions, & substances that aren’t found in stores, but go into almost all of the goods that ARE found in stores. One such company used to make commercials that explained it nicely:

I recently had the pleasure of assisting a caller from a company like this, who wanted to install three of our Hazardous Location Cabinet Cooler Systems in their facility. This particular company doesn’t make anything shown in the commercial above; they make intermediates for agricultural use (to paraphrase the commercial, “they don’t make fertilizer; they make fertilizer better”). As is the case in MANY chemical plants, a good portion of their real estate is classified as hazardous area (as defined by regulatory oversight agencies) AND subject to exposure to some fairly corrosive chemicals. Now, these places all go to great lengths to ensure safety for personnel AND equipment, through compliance AND design. So, when they needed to add durable & reliable heat protection to their electrical panels, they called EXAIR.

This was a pretty easy application, as the engineer I spoke to had gotten the internal heat loads from the equipment supplier, and already knew that 316SS construction was needed for the corrosive elements the equipment could be exposed to. The panel was in a Class I Div 2 area (flammable gasses or vapors may be present in the event of an accident or during unusual operating conditions). After calculating the external heat load, we specified a Model HZ4725SS-316 NEMA 4X (316SS Construction) Hazardous Location Cabinet Cooler System, rated for 1,700 Btu/hr, and Model 902021 24VDC HazLoc Solenoid Valve. These panels came equipped with temperature monitors that they could wire our valves into, otherwise we’d have supplied Thermostat Controlled systems.

EXAIR HazLoc Cabinet Cooler Systems are rated for Class I Div 1 & 2, Class II Div 1 & 2, and Class III environments.

EXAIR Cabinet Cooler Systems are available, from stock, to suit most any electric/electronic panel heat protection need:

  • Cooling capacities from 275 to 5,600 Btu/hr. Call me if your heat load is outside this range…we can look at customized solutions too.
  • NEMA 12 (IP54), 4, or 4X (IP66) ratings.
  • Thermostat Control – Standard, or Electronic Temperature Control.
  • Non-Hazardous Purge for contaminant exclusion on less-than-ideally sealed enclosures.
  • High Temperature models for ambient temperatures from 125°F (52°C) to 200°F (93°C).
  • Side Mount Kits when space is limited above the panel.
  • 316SS construction for particularly aggressive environments.
  • UL Classified for hazardous locations, just like the one I wrote about above.

If you’d like to find out how easy it is to provide durable and reliable heat protection for your electrical panels, give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Class 2 Div 1, Groups E, F, G Cabinet Coolers

Published on by bdwagesLeave a comment

When it comes to electrical equipment, and in our case electrical cabinets, there are regulations we all must follow for safety concerns from hazardous locations. There are explosion hazards that occur when handling flammable gases, vapors and dust. Hazardous location regulations have been designated from the NEC, CEC, OSHA and the NFPA. There is also a Globally Harmonized System (GHE) that oversees labeling the hazards of products.

In the US the governing body for electrical hazards is the NEC (National Electric Code). In Canada, it is the CEC (Canadian Electric Code). These 2 agencies work very closely together in North America, and have very few differences – the main differences concern how and where signs are posted, not the hazards themselves. Both agencies utilize document NFPA 70 (National Fire Protection Agency) as the primary basis for all electrical hazard information and requirements. The NFPA 70 outlines the different Classes and Divisions.

As we look at our Class II Div 1 groups E,F, and G Cabinet Cooler Systems, where can we actually use them? First, they are to be used in conjunction with a purged and pressurized control, system. They are not a replacement of such systems but, rather, provide cooling for them. To fully understand the environments they can be used, we need to understand the class, division and group meanings so let’s dive in…

Let’s jump right into a brief overview of the Classifications. The classifications offer a precise description of the hazardous material that is (or most likely) in an area, so that the appropriate equipment can be used, and safe installations can occur. Sometimes these classifications are easily recognized, and many times they may take a detailed study of the site. There are 3 categories of hazardous materials which define the type of explosive (or flammable) that is present:

Pixabay Image licensed by Pixabay

Class I = Flammable vapors, gases or liquids – examples would be areas such as Gasoline storage, petroleum Refineries, Dry Cleaning Plants, Fuel Servicing Areas, Spray Finishing areas, etc…

Class II = Combustible dust – examples would be Grain elevators, Flour and feed mills, Metal powders manufacturers, coal plants, etc…

Class III = Ignitable Fibers and flyings – Examples would include sawdust areas, Textile mills, Cotton processing, Cotton Seed Mills, etc..

Now as we dissect this further, we will see that each of these “Classes” are divided into 2 divisions. We many times hear these expressed as Div1 and Div 2. The Divisions tells of the likelihood that a hazardous material may be present in a flammable concentration.

Division 1 = an area where the explosive or flammable vapors, gases, dust, fibers, or liquids (as mentioned in Class definitions) can exist under normal everyday operating conditions.

Division 2 = an area in which the dangerous vapors, gases, dust, fibers, or liquids are NOT likely to be present under normal operations.

After the Classes and the Divisions come the groups.

Class 1 has 4 groups, A-D. These are all gases.

Group A = Acetylene is in the air

Group B = Flammable gases with a Minimum Igniting Current (MIC) less than 0.40 such as hydrogen, butadiene, ethylene oxide, propylene oxide

Group C = Flammable gases with a Minimum Igniting Current (MIC) greater than 0.40 such as ethyl ether, ethylene, acetaldehyde, and cyclopropane

Group D = Flammable gases with a Minimum Igniting Current (MIC) greater than 0.80 such as acetone, ammonia, benzene, butane, ethanol, gasoline, methane, natural gas, naphtha, and propane.

Class II has 3 groups, E,F and G. These are all types of dust

Group E = Combustible Conductive metal dust such as aluminum and magnesium

Group F = Combustible electrically Non-Conductive dust such as coal, carbon, charcoal

Group G = Combustible dusts not included in E or F such as flour, grain, wood, plastic and chemicals.

As we come full circle here looking at our Class II, Div 1, Groups E,F, and G Cabinet Cooler systems, we now understand the following:

  • We know that these systems are perfect for areas that contain combustible dust such as coal dust, flour, grain and feed (Class II)
  • We also know that these will work well in areas where these combustible dusts are constantly present around this Cabinet Cooler (Div 1)
  • Lastly we understand that these are a great fit for all types of dusts, whether conductive or not (Groups E,F,G)

Please feel free to reach out to myself or any of the application engineers for further questions on this or any of our amazing products.

Thank you for stopping by,

Brian Wages

Application Engineer

EXAIR Corporation
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Cover photo by Clker-free-vector-images/29545, licensed by Pixabay