Calculating Heat Loads to Cool Electronic Cabinets

With the hot summer months upon us, elevated temperatures can cause shutdowns and interference with electrical systems.  For every 10 deg. C rise above the operational temperature, the life of an electrical component is cut in half.  With Freon-based coolers, higher ambient conditions make them less effective; and opening the electrical panel to have a fan blow inside creates a dangerous hazard as well as blowing hot, humid, dirty air inside the panel.  To reduce loss in production and premature equipment failures, it is important to keep the electrical mechanisms cool.  The EXAIR Cabinet Cooler Systems are designed to do just that.

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. The EXAIR Cabinet Coolers range from 275 BTU/hr (69 Kcal/hr) to 5,600 BTU/hr (1,411 Kcal/hr) in cooling capacities.  And with the filled-out form, we can make sure that the correct model is recommended.  In this blog, I will cover a section of the sizing guide, the heat loads.

To properly cool, we need to calculate how much heat is being generated.  Heat loads come from three main areas; internal, external and solar.  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 the electrical devices.  There are three ways that we can figure 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.  The best place for the washer will be toward the top half of the panel, as heat rises.  In the sizing guide, you can mark the temperature next to “Internal temperature now”.

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.

Step C:  If you know the amount of power going into the panel, and the amount of power leaving the panel, the difference will tell us the amount of power that remains for the electrical components.  We can take a 5% average as the heat loss.

External Heat Load:  The external heat load is attributed to the environment surrounding the electrical panels.  This is a standard temperature reading in oF or oC.  Only with Step A above, we will need to know the external temperature at the time that you measured the internal heat measurement.  This needs to be placed in “External Temperature Now”.  The difference to the internal temperature will give us the heat load per square feet (square meter).  Reference chart below.  We will also need to know the highest external temperature that the panel will see.  So, during the hottest day of the hottest month, the EXAIR Cabinet Cooler will still be able to keep your electronics cool and operational.

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, the Cabinet Cooler Sizing Guide is the best tool to use to facilitate the calculations.  I gave examples above to find different ways to get the proper information.  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 $58.00 value, as a promotional item from now until the end of August 2020 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

Compressed Air and Pneumatic Systems

Compressed Air Pipe

Compressed air is used to operate pneumatic systems in a facility, and it can be segregated into three main sections; the supply side, the demand side, and the distribution system.  The supply side is the air compressor, after-cooler, dryer, and receiver tank that produce and treat the compressed air.  They are generally found in a compressor room.  The demand side is a collection of devices that will use the compressed air to do “work”.  These pneumatic components are generally scattered throughout the facility.  To connect the supply side to the demand side, a distribution system is required.  Distribution systems are pipes or tubes which carry compressed air from the air compressor to the pneumatic devices.  The three sections have to work together to make an effective and efficient system.

Compressed air is a clean utility that is used in many different ways, and it is much safer than electrical or hydraulic systems.  But most people think that compressed air is free, and it is most certainly not.  Because of the cost, compressed air is considered to be a fourth utility in manufacturing plants.  For an electrical motor to reduce a volume of air by compressing it, it takes roughly 1 horsepower (746 watts) to compress 4 cubic feet (113L) of air every minute to 125 PSI (8.5 bar).  With almost every manufacturing plant in the world utilizing air compressors larger than 1 horsepower, the amount of energy needed is extraordinary.

Let’s determine the energy cost to operate an air compressor by Equation 1:

Equation 1:

Cost = hp * 0.746 * hours * rate / (motor efficiency)

where:

Cost – US$

hp – horsepower of motor

0.746 – conversion KW/hp

hours – running time

rate – cost for electricity, US$/KWh

motor efficiency – average for an electric motor is 95%.

As an example, a manufacturing plant operates a 100 HP air compressor in their facility.  The cycle time for the air compressor is roughly 60%.  To calculate the hours of running time per year, I used 250 days/year at 16 hours/day.  So operating hours equal 250 * 16 * 0.60 = 2,400 hours per year.  The electrical rate for this facility is $0.10/KWh. With these factors, the annual cost to run the air compressor can be calculated by Equation 1:

Cost = 100hp * 0.746 KW/hp * 2,400hr * $0.10/KWh / 0.95 = $18,846 per year in electrical costs.

Filters and Regulator

If we look at the point-of-use or demand side, the compressed air is generally conditioned to be used to run and control the pneumatic system.  The basic units include filters, regulators, and lubricators.  The filters are used to remove any oil, water, vapor, and pipe scale to keep your pneumatic system clean.  They fall into different types and categories depending on the cleanliness level required.

Filter Separators are more of a coarse filtration which will capture liquid water, oil, and particulate.  The Oil Removal Filters are more of a fine filtration which can capture particles down to 0.03 micron.  They are also designed to “coalesce” the small liquid particles into larger droplets for gravity removal.  One other group is for removing oil vapor and smell.  This type of filter uses activated charcoal to adsorb the vapor for food and pharmaceutical industries.  Filters should be placed upstream of regulators.

Pressure Regulators change the pressure downstream for safety and control.  Pneumatic devices need both flow and pressure to work correctly.  The lubricator, which is placed after the Regulator, helps to add clean oil in a compressed air line.  Air tools, cylinders, and valves use the oil to keep seals from wearing with dynamic functions.  Once the compressed air is “ready” for use, then it is ready to do many applications.

For EXAIR, we manufacture products that use the compressed air safely, efficiently, and effectively.  EXAIR likes to use the 5-C’s; Coat, Clean, Cool, Convey and Conserve.  We have products that can do each part with 16 different product lines.  EXAIR has been manufacturing Intelligent Compressed Air Products since 1983.  Compressed air is an expensive system to operate pneumatic systems; but, with EXAIR products, you can save yourself much money.  If you need alternative ways to decrease electrical cost, improve safety, and increase productivity when using compressed air, an Application Engineer at EXAIR will be happy to help you.

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

Preventative Maintenance for EXAIR Filters

Good engineering practice calls for point of use filtration and moisture removal, such as that provided by EXAIR Filter Separators.

I read a white paper from Parker Hannifin about compressed air filters.  The idea behind the paper was to remember your filter replacements.  Compressed air can be dirty with water, oil, pipe scale, etc.  As the filters capture the contamination, it will start to build pressure drop.  Remember, pressure drop is a waste of energy in your compressed air system.

Majority of EXAIR products use compressed air for cleaning, cooling, conveying, static elimination, coating and more.  To help keep them running efficiently, it is important to supply them with clean, dry, pressurized air.  EXAIR offers a line of Filter Separators and Oil Removal Filters to supply quality air to your equipment.  In this blog, I will explain the two types of filters that we carry and the maintenance requirements.  Filters and preventative measures can play an important part in your compressed air system.

Filter Separators are used to remove bulk liquid and contamination from the compressed air stream.  They utilize a 5-micron filter with a mechanical separation to help remove large amounts of dirt and water.  This type of filter would be considered the minimum requirement for filtration.  Most of the Filter Separators come with an auto-drain to automatically dispense the collection of oil and water.  EXAIR offers a variety of port sizes and flow ranges to meet your pneumatic flow requirement.  For maintenance, the filter elements should be changed once a year or when the pressure drop reaches 10 PSID (0.7 bar), whichever comes first.  I created a list in Table 1 below showing the correct replacement element kits for each model number.  And for any reason, if the bowl or internal components get damaged, we also have Rebuild Kits as well.  Just remember, the air quality is very important for longevity and functionality of your pneumatic systems and even for EXAIR products.

The Oil Removal Filters can make your compressed air even cleaner.  They work great at removing very small particles of dirt and oil.  They are made from glass fibers and can remove particles down to 0.03 micron.  They are designed to collect small particles and to coalesce the liquid particles into a large droplet for gravity to remove.  Because of the fine matrix, Oil Removal Filters are not great for bulk separation.  If you have a system with lots of oil and water, I would recommend to use the Filter Separator upstream of the Oil Removal Filter.  As with the Filter Separator, the filter element should be changed once a year or at a pressure drop of 10 PSID (0.7 bar).  EXAIR also offers a variety of port sizes and flow ranges.  Table 1 below shows the replacement Element Kits as well as the Rebuild Kits.  If the application requires very clean compressed air, the Oil Removal Filter should be used.

Table 1

By using EXAIR filters, they will clean your compressed air to prevent contamination on parts, performance issues, and premature failures.  As an ounce of prevention, you should add the replacement elements in stock and enter them in your preventative maintenance program.  With quality air, your pneumatic system and EXAIR products will provide you with effective, long-lasting performance without any maintenance downtime.  If you would like to discuss the correct type of filters to use in your application, you can speak with an Application Engineer.  We will be happy to help you.

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

Air Atomizing Nozzles for Blue Jean Manufacturing

Acid washed Jeans

I wrote an earlier blog on how a blue jean manufacturer used EXAIR Air Operated Conveyors to help transport pumice stones into washers for stonewashed jeans.  You can find it here, “The EXAIR Air Operated Conveyors with stonewashed jeans.”  This same company contacted EXAIR again for another application.  With great customer service and thousands of products in stock, this customer stated it was an easy decision to come back to us.  This time it was for a spraying application.  I was happy to help them again.

Beside stone-washing, there are other ways to give that “worn out” look to blue jeans.  In this operation, they would scuff areas on the denim material with sandpaper.  To brighten that area, they would manually spray Potassium Permanganate over the jeans.  This reaction would fade the blue in the scuffed areas during the washing cycle.  They wanted to automate this process and move away from the manual operation (reference photo above).  So, I recommended our Air Atomizing Nozzles.

No Drip Atomizing Family

To tell you about EXAIR Air Atomizing Nozzles, they use compressed air to shear liquid into very fine particles.  The smaller the particles, the more surface area is produced.  Thus, less liquid material is required which will save money on the expense of the liquid.  EXAIR offers three different body sizes in NPT or BSP conversions; 1/8”, 1/4”, and 1/2”.  They are made from stainless steel for corrosion resistance.  We have an Internal Mix and an External Mix for use with pressurized liquid, and a Siphon Fed for open containers.

With each body style, we have a variety of liquid caps for different flow amounts, and an assortment of air caps to direct the fine mist.  For the Atomizing Nozzles, EXAIR can offer a No-Drip option and brackets.  The No-Drip option will stop liquid flow when the compressed air is turned off which will not allow the liquid to drip from the nozzle.  The brackets fit snugly around the body to support the Atomizing Nozzles for precise spraying.

For this application, I recommended the model AW9010SS.  This is a 1/8” NPT No-Drip Internal mix Atomizing Nozzle with a wide-angle round pattern.  The liquid flow rate fit their application with a maximum of 3.5 GPH (13.2 LPH).  The wide spray angle was able to cover the patterns on the denim material.  The potassium permanganate was delivered to the Atomizing Nozzle with a liquid pump, and with the No-Drip Option, they could start and stop spraying accurately and quickly with a simple compressed air solenoid valve.  Also, the model AW9010SS is a durable lightweight nozzle; and with the model 901786 bracket, the Atomizing Nozzles were easily mounted to the end of a robot arm for automation.

The EXAIR Atomizing Nozzles were able to replace the manual operation.  The amount of liquid material that this denim manufacturer was able to save was near 20%.  Depending on the expense of the fluid that you use, this can be quite a savings.  Also, they found that the “worn” areas were more consistent with accurate spraying and an even amount of potassium permanganate.

And as an added note with the safety issues in spraying potassium permanganate, the Atomizing Nozzles were a more effective way to reduce the hazard as a substitution control.  The operator with personal protective equipment, or PPE, is the least effective way for controlling occupational hazards.  The automated system with EXAIR Atomizing Nozzles was able to remove the operator from the hazard.

If you have a liquid that you would like to spray evenly, efficiently, and effectively; EXAIR Atomizing Nozzles can do that for you.  As with the customer above with the Air Operated Conveyors or Atomizing Nozzles, the quality of the products and the great customer service was what caused this customer to use EXAIR.  If you would like to experience the EXAIR way, you can contact an Application Engineer.  We will be happy to help you.

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

 

Photo: Stonewash Jeans by realworkhardPixabay License.