Tag: refrigerant

Critical Equipment Needs Reliable Heat Protection

Published on by Russ BowmanLeave a comment

Electricity and water don’t mix. Electrical and electronic components don’t like many contaminants that can be found in industrial settings, either. Exposure to moisture or dirt are surefire ways to “let the smoke out” – it can be just as bad as letting them overheat. Once that’s happened, replacement of the failed components is usually the only option. THAT can get expensive not only in the cost of the component, but also in the downtime waiting for it to come in…which can be a REAL problem if they’re not in stock.

Luckily, there’s no shortage of cooling devices for electrical panels. They all have certain areas/situations where they’ll work just fine, but most have areas/situations that can cause real problems:

Panel air conditioners work a lot like the a/c in your home or office, and if you’ve ever used window a/c units, they work EXACTLY like those. Since they cool the air as they recirculate it through the space, they have filters to catch any particulate. If the panel isn’t sealed tightly, this filter may very well require regular attention. They also use air from the surrounding environment to condense the hot refrigerant gas:

Evaporator: heat from inside air is transferred to a refrigerant, flashing it from liquid to gas.
Compressor: pressurizes low pressure refrigerant gas.
Condenser: transfers heat from hot, high pressure refrigerant gas to outside air.
Expansion valve: lowers pressure (and temperature) of condensed refrigerant, sending it to the evaporator to continue the heat transfer cycle.

If the condenser coils are exposed to contaminants (dust, oil, chemical vapors, etc.), they’ll be subject to fouling & corrosion, making panel air conditioners more prone to failure in more aggressive environments. Also, since they use air from the environment as a heat sink for the refrigerant, their cooling capacity is inversely affected by the ambient temperature.

Heat Pipe systems also use refrigerant, but they don’t have any moving parts to wear. Since they don’t have a compressor or expansion valve, though, they’re incapable of cooling the panel below ambient temperature. The evaporator fins or coils are also still subject to environmental contamination, so they have the same limitations as a panel a/c system…and are further limited in hot spaces.

Panel fans are easily the least expensive cooling method. They’re usually fitted with filters for the outside air that they move through the enclosure. Like heat pipes, they can’t cool the enclosure to a temperature below ambient for the area, and the filters are still subject to clogging from airborne particulate, and since those filters have to be coarse enough for the fan’s cooling air flow, smaller particulate can still make it inside the panel….along with any vapors or gases that could condense, or worse, corrode components inside the panel. If the fan on a home computer can get as dusty as the one in the photo to the left, imagine how much worse the one on a control panel on a factory floor can get.

Liquid to Air coolers use liquid – the most common being chilled water – for cold fluid flow through coils inside the panel to remove heat, which is then transferred to ambient through a refrigerant chiller, or a fan & radiator. The inside coils are subject to fouling and condensation if the panel isn’t sealed tightly, and the refrigerant chiller has the same limitations as a panel a/c unit. If it uses a fan & radiator, it (like panel fans or heat pipes) can’t cool the panel to less than ambient temperature in the area.

EXAIR Cabinet Coolers have no moving parts and use compressed air as the sole cooling medium, so they’re not affected at all by environmental conditions. When they’re properly installed on a sealed enclosure, the only thing the inside of the enclosure ever sees is clean, cold, moisture-free air. Wherever your panel is, and regardless of the environment, EXAIR has a wide selection of cooling capacities, features, and materials of construction. Consider:

  • 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), NEMA 4, or NEMA 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 where space is limited above the panel.
  • 316SS construction for particularly aggressive environments.
  • UL Classified systems for hazardous locations: Our HazLoc systems are approved for Class I Div 1, Class II Div 1 & Class III areas, and ATEX systems are approved for Zones 2 & 22.
Inside, outdoors, high temperature, dirt/dust/humidity, corrosive and classified environments are no problem for EXAIR Cabinet Cooler Systems

If you need heat protection for electrical/electronic panels, EXAIR has solutions. To find out more, give me a call.

Russ Bowman, CCASS

Application Engineer
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Father’s Day Weekend & Leak Detection

Published on by Brian FarnoLeave a comment

In case you didn’t know, yesterday was Father’s Day. In our household, both Father’s Day and Mother’s Day are pretty low-key, and we normally just get some much-needed family time in. This year for Mother’s Day we prepared the patio and outdoor living space at our home for the Summer activities. For Father’s Day, the schedule was a little different. My wife and oldest had a play to go to in the early afternoon and I had a list of repairs to do as well as some recovery from a dodge ball tournament on Saturday. While most of my repairs were things like fixing a leaking hose, unpacking from the tournament, and weeding the garden, I did not have any major repairs on my list which meant I could take the younger two daughters and head to the pool. That ice-cold water definitely helped with the recovery part of my day, so we went. Met the rest of the crew after their show and had some nice ice cream time then home. I was feeling pretty good as my tasks were all completed, and I was going to be able to just enjoy the meal my wife had fixed for dinner and play some games with my girls. Well, the house had other plans, we arrived home to a thermostat that had crept up while we were gone.

Ice from the compressor line in the condensing coil.
While the leak detector wasn’t out, there was no shortage of thermometers being used here along with a slide rule. (Leak Detection had been completed.)

Now, our HVAC system has limped along for probably a decade longer than most, and we continue to regularly maintain it. This is a true testament to how well preventative maintenance can truly expand the life of an item. Needless to say, during my routine inspection and maintenance at the start of the year, we found the unit was low on refrigerant. One of the first steps we performed when we saw it was starting to freeze up was to begin testing for leaks. This task takes a special gas detection meter that will sniff out the refrigerant vs. just air movement. Sure enough, we found a corroded joint in the A-Coil that has developed a fairly considerable leak. This tool made me think of the Ultrasonic Leak Detector that we sell here at EXAIR. It also made me start to correlate how a leak in a refrigeration system can cause the entire process to ice over because there isn’t enough refrigerant present and so the entire system begins to work harder and harder and the coil temp drops below freezing. The humidity in the air begins to collect on the A-Coil inside the house because the coil is so much cooler than the humid air around it and the ice starts to form. Once the ice forms you restrict the airflow through the coil which causes more ice to form and eventually no airflow happens and the entire compressor line will freeze. This often can lead to other failed parts if not discovered early enough. How is this like a compressed air system?

Well, leaks in a compressed air system cause the compressor to work overtime. It drops efficiency within the other items in the system which creates a lack of performance and potentially shuts down the system. Leaks can be found by utilizing a less specialized, Ultrasonic Leak Detector which can be seen in operation in the video below. Fixing these leaks can easily put capacity back in and save additional maintenance and replacement costs.

If you want to discuss how the Ultrasonic Leak Detector can save you money and costly shutdowns, contact an application engineer today.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Intelligent Compressed Air: Refrigerant Dryers

Published on by Tyler DanielLeave a comment

When we talk with customers about their EXAIR Products, we also discuss the quality of their compressed air. Many of our products have no moving parts and are considered maintenance-free when supplied with clean, moisture free compressed air. One of the most critical aspects of a compressed air distribution system is the dryer.

No matter where you are in the world, the atmospheric air will contain water vapor. Even in the driest place in the world, McMurdo Dry Valley in Antarctica, there is some moisture in the air. As this air cools to the saturation point, also known as dew point, the vapor will condense into liquid water. The amount of this moisture will vary depending on both the ambient temperature and the relative humidity. According to the Compressed Air Challenge, a general rule of thumb is that the amount of moisture air can hold at a saturated condition will double for every increase of 20°F. In regions or periods of warmer temperatures, this poses an even greater problem. Some problems that can be associated with moisture-laden compressed air include:

  • Increased wear of moving parts due to removal of lubrication
  • Formation of rust in piping and equipment
  • Can affect the color, adherence, and finish of paint that is applied using compressed air
  • Jeopardizes processes that are dependent upon pneumatic controls. A malfunction due to rust, scale, or clogged orifices can damage product or cause costly shutdowns
  • In colder temperatures, the moisture can freeze in the control lines

In order to remove moisture from the air after compression, a dryer must be installed at the outlet of the compressor. It is recommended to dry the compressed air to a dew point at least 18°F below the lowest ambient temperature to which the distribution system or end use is exposed. A dew point of 35-38°F is often sufficient and can be achieved by a refrigerated dryer (Best Practices for Compressed Air Systems). This makes the refrigerant dryer the most commonly used type in the industry.

A refrigerant dryer works by cooling the warm air that comes out of the compressor to 35-40°F. As the temperature decreases, moisture condenses and is removed from the compressed air supply. It’s then reheated to around ambient air temperatures (this helps to prevent condensation on the outside of distribution piping) and sent out to the distribution system.

With your air clean and dry at the point of use, you’re making sure you get the most out of EXAIR’s Intelligent Compressed Air Products without adhering to pesky maintenance procedures.

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

Compressor image courtesy of Tampere Hacklab via Flickr Creative Commons License

Refrigerant Dryers for Compressed Air

Published on by EricKuhnash@EXAIR.comLeave a comment

A refrigerant air dryer is is used with compressed air for removing moisture from the compressed air system . Compressed air always contains water because your are taking in outside air which contains moisture. It is vital to have a compressed air dryer system in place to protect your equipment and tooling from damage. How does a refrigerant dryer work and why select this type of dryer system?

Refrigerant air dryers are commonly used as they are easy to operate, economical and low maintenance. Once installed it is likely that you may never have to think about it again. The system works by cooling the air to around 37 degrees Fahrenheit. At this point all the water vapor condenses into water. The water can then be removed by a simple water trap. Once the liquid water has been removed the air gets reheated to room temperature. Since most of the water has been condensed and removed the reheated air will be significantly dryer than from before.

Fundamental Schematic of a Refrigerant-Type Dryer

The cooling process of refrigerated dryers is the same process used in refrigerators and freezers. The liquid refrigerant is evaporated in a separate circuit and used to cool down the compressed air. As the air cools the refrigerant gets warmer. The refrigerant moves into a compressor and gets re-cooled in a condenser, this process is a continuous cycle as more air is introduced into the compressor.

Here a few items to consider when making your purchase:

Maximum pressure: The dryers max pressure should be the same or higher than your compressor.

Inlet Temperature: If you exceed maximum inlet temperature you are at risk of damaging parts of your equipment. Some refrigerated dryers have an after cooler making sure your compressed air stays within acceptable temperature ranges.

Maximum Flow: Make sure your dryer has the capacity needed to there are no drops in air pressure.

Maximum Room Temperature: If you are placing your refrigerated dryer into a room with a hot environment there is a change that it could overheat, Make sure that your max operating temperature for the dryer is able to accommodate the max temperatures in the room where it will be operating.

EXAIR wants you to be successful in every aspect of your compressed air system. If you have a need for any of EXAIRS Intelligent Compressed Air Systems please give any of our Application Engineers a call or contact us through our TecHelp.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK