## Calculating and Choosing the Right Cabinet Coolers

“I need one of your Cabinet Coolers for my control panel, the dimensions are 24″ H x 30″ W x 16″ D, what do you recommend?”. This is a very common inquiry we receive when discussing our Cabinet Cooler Systems for the first time with a potential customer. While it would be nice if it was a simple as using just the dimensions, there is more that goes in to making the proper selection.

Following explains how to go about calculating and choosing a Cabinet Cooler System. If, at any time, you prefer EXAIR to calculate and assist with your choice – contact our Application Engineering department and we will be happy to get you up and running.

Our Cabinet Coolers are sized by cooling capacity in Btu/hr., which range from our lowest of 275, up to our largest Dual System providing 5,600 Btu/hr. Now if you know the Watts loss , we can convert this over to Btu/hr. (Watts X 3.41 = Btu/hr.). If you are unsure, we need to determine the current heat load of the cabinet by using the dimensions, current temperatures (internal and external) and worst case external temperature and the desired temperature you are looking to maintain inside the enclosure. To simplify this process, we offer our Cabinet Cooler Sizing Guide.

The current internal and external temperature will determine one of your ΔT’s (temperature differential), which is used to determine a multiplier from the table below. We then take your maximum external temperature and your desired internal temperature to give us another ΔT and multiplier. Use the sq. ft. of the cabinet and multiplying it by the temperature conversion multipliers. Add these sums together to determine the total heat load in Btu/Hr. This value will help you to choose the proper Cabinet Cooler system to solve your heat problem.

Now that we have the heat load properly calculated, we need to know the NEMA class of the enclosure. We offer NEMA 12 for general use where there aren’t any corrosives or liquids present, NEMA 4 for wet or damp environments and NEMA 4X for wet, corrosive applications.

We offer Thermostatically Controlled Systems with available voltages of 120VAC, 240 VAC or 24VDC. This is the most efficient means of operation as the unit only operates when the internal desired temperature is exceeded. In addition, we also offer Continuous Operating Systems, providing constant cooling and positive pressure into the cabinet. Each system  includes a filter separator for the supply line to keep water and dirt from entering the cabinet as well as duct tubing.

Of course, if you need any additional assistance, you can always contact one of our application engineers. If you can provide a little bit of information, we can do the calculating and get you on your way.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

## EXAIR’s Cabinet Cooler Systems Cool Electrical Enclosures

One of the main focuses for Cabinet Cooler Systems is to cool electrical enclosures that are overheating due to inadequate cooling, failing air conditioners, or heat exchangers that are not performing due to high ambient conditions.  Another focus is the fact that the Cabinet Cooler Systems don’t require refrigerant based coolants, or fans that can move dirty ambient air into the cabinet. This is the portion I would like to focus on today.

If there are vents on the enclosure then these are sometimes covered with a filter media that is an easily forgotten maintenance item –  sometimes they are even removed.  This is an issue as it starts to allow the contaminants from the surrounding area to begin to enter the inside of an enclosure.  In case you have never seen a circuit board that is covered in oil mist and metal chips, it is terrifying to see a maintenance person that is trying to troubleshoot the machine for failures.  Not only does this present a fire hazard but it also presents the internals of the panel with a strong probability of failure.

Another item I have personally seen fail in the field are small fans mounted within enclosure vents to help circulate air through the enclosure.  This is a great idea if the ambient environment is climate controlled and has no dirt or debris in the air.   Even in a facility that is climate controlled there is still potential for airborne debris, dust, and contaminants to enter the cabinets. These are merely accelerated into the cabinet by the fan and distributed throughout the entire enclosure instead of just coming in and covering the area just inside of the vent.

The solution to all the problems above which can easily save thousands of dollars worth of damaged circuit boards or drives is an EXAIR Cabinet Cooler System.  The Cabinet Coolers will all provide a slight positive air flow within the enclosure and will help to keep those external ambient conditions out of the cabinet and away from valuable electronics.  Even with our thermostatically controlled systems (which turn on and off as needed to maintain internal temperature AND save air) we offer a Non-Hazardous Purge option which will permit a 1 SCFM flow of air through the Cabinet Cooler to always keep a slight positive pressure within the enclosure. When the cabinet needs to be cooled, it will open the solenoid valve and provide the full rate of cooling from the Cabinet Cooler System.  The Non-Hazardous Purge function is available for all three NEMA types of Cabinet Cooler Systems, 12, 4, and 4X.