EXAIR Cabinet Cooler Systems: Thermostats and Accessories

For most industrial enclosure cooling applications, a temperature of 95°F (35°C) is sufficient to be below the rated maximum operating temperature of the electrical components inside the cabinet. So, it is important to turn the cabinet cooler system on to keep the components cool, but at the same time we all know compressed air can be expensive if you over use it. A thermostat allows you to turn the cooler off when the enclosure is at or below the desired temperature, saving compressed air over continuous operation.

Cabinet Cooler

Here at EXAIR we are all about Engineered Solutions that will not only save you money but help your company “Go Green” by drastically lowering your energy costs. And when it comes to Cabinet Coolers, we have several options to control and manage the compressed air supply.

The most popular option is our Thermostat Control. EXAIR thermostats feature a bimetallic contact strip to open and close the electrical circuit in response to air temperatures.  These thermostats quickly respond to changes in air temperature and are specifically suited for their intended use.  Preset for 95°F (35°C), a suitable temperature for most electronic devices, these thermostats are fully adjustable for specific application needs. When thermostat closes it then turns the solenoid valve off turning the compressed air supply off. These thermostats are available in 12VAC, 240VAC and 24VDC.

Thermostat and ETC

In the event a more sophisticated thermostat control is needed, Electronic Temperature Control units can be implemented.  These standalone units utilize a thermocouple to determine internal cabinet temperatures which display onto a digital readout.  Push-button controls on the digital readout board allow for easy modification of the internal cabinet temperature set-point.  When the desired internal temperature is reached, the Cabinet Cooler system will turn off automatically.

One accessory that will give the flexibility to install EXAIRS cabinet cooler system is our Side Mount Kit. Sometimes there isn’t room above an electrical panel to fit the Cabinet Cooler, even though it takes just 5″ to 7.25″ of space above. In these cases, the Side Mount Kit is available to handle any of the Cabinet Cooler sizes and NEMA ratings. The NEMA 4 and 4X Cabinet Coolers must be mounted vertically for the unit to properly resist the ingress of liquids and maintain the integrity of the cabinet NEMA rating.

EXAIR NEMA 12 Cabinet Cooler System w/ Side Mount Kit
NEMA 12 Cooler with Side Mount Kit

The Side Mount Kits install into a standard electrical knockout (1-1/2 NPS) for easy installation.

If you’re in need of a suitable cooling solution for an industrial enclosure, consider an EXAIR Cabinet Cooler systems.  They’re smaller than traditional AC units, faster to install, and require little-to-no-maintenance.  Feel free to contact an EXAIR Application Engineer with any questions, or fill out our online Cabinet Cooler Sizing Guide to have an Application Engineer contact you.

Jordan Shouse
Application Engineer
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EXAIR Cabinet Coolers vs. Air to Air Heat Exchangers

At EXAIR we’ve been providing enclosure cooling solutions for decades, and in many cases those cooling solutions have remained in place for decades as well.  In the time we’ve been in the market with industrial enclosure cooling solutions we’ve encountered a number of alternative means for enclosure cooling.  One of those methods is an air-to-air heat exchanger.

heat exchanger 1
Heat exchanger

An air-to-air heat exchanger uses the temperature differential between the ambient air surrounding an enclosure and the hot air inside an enclosure to create a cooling effect.  A closed loop system exchanges the heat inside the enclosure with the outside air in an effort to maintain a set internal temperature.  The heat exchange of most air-to-air unit relies on a heat pipe, a heat-transfer device which converts an internal refrigerant liquid into vapor by placing one end of the pipe in contact with the hot environment.  The heated vapor travels to the other end of the pipe which is in contact with a cooler environment.  The vapor condenses back into a liquid (releasing latent heat) and returning to the hot end of the pipe and the cycle repeats.

But, this type of a solution does give some cause for concern, especially when considering their use in an industrial environment.  Here are the key points to keep in mind when comparing an air-to-air cooler to an EXAIR Cabinet Cooler.

Cabinet Cooler Family
EXAIR Cabinet Coolers

Required temperature differential based on ambient air temp

An air-to-air heat exchange relies on the ΔT between the ambient air temperature and the internal enclosure air temperature to produce cooling.  If this ΔT is low, or the ambient temperature rises, cooling is diminished.  This means that as the temperatures in your facility begin to rise, air-to-air heat exchangers become less and less effective.  Larger air-to-air heat exchangers can be used, but these may be even larger than the enclosure itself.

EXAIR Cabinet Coolers rely on the ΔT between the cold air temperature from the Cabinet Cooler (normally ~20°F) and the desired internal enclosure temperature (normally 95°F).  The cold air temperature from the Cabinet Cooler is unaffected by increases in ambient temperatures.  The large ΔT and high volume cold air flow produced by a Cabinet Cooler results in more cooling capacity.  And, we can increase cooling capacity from a Cabinet Cooler without increasing its physical footprint, which is already much, much smaller than an air-to-air type of unit.

 

Cooling in high temperature environments

Due to their nature of operation, an air-to-air heat exchanger must have an ambient temperature which is lower than the desired internal temperature of the enclosure.  If the ambient air has a higher temperature, air-to-air units provide zero cooling.

Cabinet Coolers, on the other hand, can be used in hot, high temperature environments up to 200°F (93°C).

EXAIR's High Temp Cabinet Cooler Systems
High temperature Cabinet Coolers

 

Cooling in dirty environments

Dirt in the ambient environment will impact cooling performance with an air-to-air heat exchanger.  In order for the air-to-air unit to effectively remove heat, the heat pipe must have access to ambient air.  With any exposure to the ambient environment comes the possibility for the ambient end of the heat pipe to become covered in ambient contaminants such as dust.  This dust will create an insulation barrier between the heat pipe and the ambient air, decreasing the ability for the heat pipe to condense the vapors within.  Because of this, most air-to-air devices use filters to separate the heat pipe from the ambient environment.  But, when these filters become clogged, access to ambient temperatures are reduced, and cooling capacity of the air-to-air unit reduces as well.

Cabinet Coolers have no problem operating in dirty environments.  In fact, it is one of their strengths.  Without any moving parts to wear out or any need to contact ambient air for cooling purposes, a dirty environment poses no problems.  In fact, check out this blog post (and this one) about EXAIR Cabinet Coolers operating maintenance free for years in dirty environments.

exair-cabinet-cooler-03-2002-2008
NEMA 12 Cabinet Cooler in a Dirty Environment

Size and time required to install

Air-to-air heat exchangers vary in size, but even the smallest units can have large dimensions.  Many applications have limited space on the enclosure, and a large, bulky solution can be prohibitive.  Couple this with the time and modification required to the enclosure to install a large air-to-air unit, and the “solution” may end up bringing additional problems.

Another key aspect of the Cabinet Cooler is its size.  Small, compact, and easy to mount on the top or side of an enclosure, Cabinet Coolers install in minutes to remove overheating problems.

 

Heat within an electrical cabinet can be a major issue for manufacturing companies. The costs associated with down time and repairs on sensitive electronics that fail due to heat or environmental contaminants, are an unnecessary burden. If you have any questions about how an EXAIR Cabinet Cooler can solve problems in your facility, contact an EXAIR Application Engineer.

Jordan Shouse
Application Engineer
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Twitter: @EXAIR_JS

Using EXAIR Cabinet Coolers to Replace Fans

3050 with qs
Which device is causing the overheating condition?

When an electrical device mounted inside a control panel goes offline due to an overheating condition, it can be difficult to determine which component in the panel is the root cause.  There may be an intermittent heat load from a variable frequency drive that isn’t present when troubleshooting, making things appear to be OK.  Or, the overheating condition may only happen during peak operation on days with high ambient temperatures.

Fortunately, no matter the root cause, an EXAIR Cabinet Cooler can maintain temperature within the enclosure at a desired set-point, eliminating overheating conditions and lost throughput due to downtime.

IMG_3052
We investigate to determine what is housed inside of our customer’s electrical control panels.

When calculating heat load, EXAIR Application Engineers consider the components within the control panel.  We inquire with our customers regarding devices such as VFD’s, which may lead to temperature spikes, or fans, which actively remove heat (albeit that they often force dirt and debris into the enclosures they’re designed to be cooling).

IMG_3053
To accurately calculate heat load, we require the diameter of any fans installed on the enclosure.

Fans can be particularly important, because with the installation of any EXAIR Cabinet Cooler, all external fans will need to be removed, and their openings will need to be sealed (internal fans can remain in place).  So, this means we have to account for any heat the fans may already be removing from the application, even if it isn’t enough to keep the enclosure cool.

IMG_3051
Measure any fans used to bring ambient air into the enclosure.

In order to determine the amount of heat a fan is removing from an application, we consider the diameter of the fan, which corresponds to a typical air flow volume in CFM (cubic feet per minute).  We then consider that 1 BTU/hr. is the amount of heat required to raise the temperature of one pound of water by 1 degree Fahrenheit, and it is also the amount of heat needed to raise/lower the temperature of one cubic foot of air by 1 degree Fahrenheit in one minute.  This means that for every CFM the fan is moving, we are reducing the temperature of the air by 1°F .  To put it another way, we remove 1 BTU/hr. for every °F * every CFM the fan is moving.

As an example, a 3″ fan will move 22 CFM.  In an enclosure with a current temperature differential of 15 degrees Fahrenheit, this fan is removing 330 BTU/hr.

15°F * 22 CFM = 330°F*CFM

15°F

x 22 CFM X 1 Btu/hr = 330 Btu/hr

CFM °F

The fans holes should be covered up with sheet metal using rivets, caulk/sealant, duct tape or other ingenious methods you know of. But please cover and seal the cabinet as well as you can.

Using the Cabinet Cooler Sizing Guide and the experience of the EXAIR Application Engineers, we can accurately calculate heat load of an overheating electrical control panel.  When you need help with determining which Cabinet Cooler to use, contact an EXAIR Application Engineer.  We’re here to help.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE