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

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

Hazardous Locations need Cabinet Cooling too!

Hazardous Locations are a tricky opponent for electrical panels and controls. To safely be in a HAZLOC they either have to be rated for that Environment or they need to be enclosed in a Cabinet that is purged and pressurized to keep any explosive gases, fumes, or dusts out of the Cabinet. This is no new thing, however as the Industrial revolution 4.0 continues to grow and progress products are continually being added to HAZLOC areas. For example, robotic controls, analyzers, motors and switch gears now use electronic accessories to meet the needs for, speed, process control and energy efficiency, which often renders the equipment unsuitable for use in hazardous locations.  While the demand for these new devices continues to grow, not all of these items are able to be made intrinsically safe. And the items that are not will need to be enclosed in a cabinet where heat will build and you need to manage that heat load while retaining the positive pressure a purge and pressurization is putting on the panel.
EXAIR HazLoc Cabinet Cooler Systems are rated for Class I Div 1 & 2, Class II Div 1 & 2, and Class III environments.
First, we need to know what Class, Division, Group and Temp Code your area falls in. Area Classification Methods  The NFPA (National Fire Protection Association) establishes area classifications using three factors. Identified as Classes, Groups and Divisions, these factors are combined to define conditions of specific areas. Class Ratings – Classes are used to define the explosive or ignitable substances that are present in the atmosphere. Class I – Flammable gases or liquid vapor. Class II – Ignitable metal, carbon or organic dusts. Class III – Ignitable fibrous materials. Division Ratings – Divisions are used to define the degree of hazard by determining the explosive or ignitable substance’s expected concentration in the atmosphere. Division 1 – Contains substances under normal conditions Division 2 – Contains substances under abnormal conditions Group RatingsGroups are used to define substances by rating their explosive or ignitable nature, in relation to other known substances. TYPICAL CLASS I SUBSTANCES Group A – Acetylene Group B – Hydrogen or > 30% Hydrogen by Volume Group C – Ethyl Ether & Ethylene Group D – Acetone, Ammonia, Benzene & Gasoline TYPICAL CLASS II SUBSTANCES Group E – Aluminum, Magnesium & Alloys Group F – Carbon, Coke & Coal Group G – Flour, Grain, Wood, Plastic & Chemicals Temperature Class – A Temperature Class is a term that is allocated within a hazardous area or zone to instruments and equipment. The classification or rating signifies the levels of thermal energy allowed in a particular area or produced by specific equipment. EXAIR products are Able to be used in locations at or lower than T3C. 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,
    • Class 1 Div 1, Groups A,B,C and D
    • Class 2 Div 1, Groups E,F, and G
    • Class 3
    • Temp T3C
When choosing products for use in classified areas, it’s critical to ensure safety through compliance, and the HazLoc Cabinet Cooler Systems allow you to do that, with simplicity and reliability.  If you’d like to discuss an enclosure cooling application, in or out of a classified area, give us a call. Jordan Shouse Application Engineer Send me an Email Find us on the Web  Like us on Facebook Twitter: @EXAIR_JS

Video Blog: Cabinet Cooler® System Calculator

In may I wrote a Blog Announcing our new Calculator tool on EXAIR.COM! You can read it here!

The Video below will walk you through how to get the information you need to fill the form in, and take you all the way to final where you can add it to your cart!

By providing certain information like size of the enclosure, NEMA rating needed, and environmental conditions, this new calculator will sort through our large selection of ready-to-ship Cabinet Cooler® Systems and provide instant feedback on the best model number for any applicable electrical enclosure.  Taking the guess work out of the equation, EXAIR’s Calculator ensures the customer that they can be confident in selecting the correct product for their unique specifications. You can even Print the form for your records!

If you have any questions or need additional support with the Sizing Calculator please reach out to one of our application Engineers give us a call. Or shoot us an email to techelp@exair.com

Jordan Shouse
Application Engineer

Send me an Email
Find us on the Web 
Like us on Facebook
Twitter: @EXAIR_JS

Cabinet Coolers: How to Determine Heat Loads

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