The past two weeks here in Cincinnati have reminded me just what humidity is all about. While the static charge in my garage at home is at an all-time low, the humidity is enough to make me wish I had gills to breathe. Even rucking before work has become a rather sweaty event. When I am rucking, one of the 4 Rules of Rucking is, #1 Always Look Cool. This is an idiom as in don’t let people see you sweat. If you are stressed, just stay cool, keep a level head and look the part. A good pair of aviators always helps to hide what your eyes can’t.

Then I open my garage fridge, because every Midwesterner has their old kitchen fridge in the garage, right? Grab a nice cold aluminum can out. And before I can put it in a thermal insulating housing, I see the condensation of the humidity forming on the aluminum. This makes me think of some of the electrical panels I encountered during my time in machine shops.

I once approached a vertical machining center whose spindle chiller, with a thermo-couple failure, had been cooling the spindle continuously during the summer months. This spindle looked like the ice-cold aluminum can I had sitting out on my workbench yesterday. Fully covered in condensate from the humidity in the air. Condensate collected on an aluminum can and leaving a ring of water on a workbench is one thing. Water running down a high-speed spindle and causing issues with a dry machining process is another. This also reminded me of a recent call where a new customer wanted help sizing a Cabinet Cooler System to replace an air-to-air heat exchanger that had failed. When walking through the information needed to size the panel, I reached the Internal Temp Desired field, and there was a pause. While I thought maybe they were checking their notes, they came back with 72°F. I wrote down the value on my notepad, then asked, “That’s oddly specific. Is there a piece of equipment that alarms out over 72°F that we are trying to protect?” The response I received was no. So I asked what the need was for this low set point.

I dug further with them, and it turned out that’s what they kept the engineers’ office set for in the summer, so they thought my question was odd and figured, if they are comfortable there and their computer on their desk operates well, then it must be a good temperature. This is not an incorrect statement. The control cabinet for the machine would operate just fine at 72°F; however, all the electronics that were in the panel were rated up to 104°F before they overheat, so it doesn’t quite make sense to extend the cooling capacity needed to reach that 72°F requested set point. Once we talked this over, we settled on the standard of 95°F for the internal set point with the understanding that by using a thermostatically controlled system, they could adjust it down lower if they really wanted to. In the end, we saved them some energy by sizing the Cabinet Cooler System to meet the demands of their industrial electronics, not what makes a person feel comfortable.

This isn’t always the case; occasionally, there is a panel that requires a low maximum temperature in order to keep a critical piece of equipment stable. This is why we ask the questions to validate any concerns with the data we are viewing as Application Engineers. This is also why we have built in a number of warnings/alerts on our Online Cabinet Cooler Sizing Calculator.

If you have a panel that needs to be cooled, the online calculator has fields for all the information we need. If you want to walk through the math behind the calculator and talk through the reasons we ask for the information that we do, you can either call, email, or even live chat with an Application Engineer, and we will gladly walk you through our process and the math to determine which Cabinet Cooler System is right for your needs.

Brian Farno, MBA – CCASS Application Engineer

BrianFarno@EXAIR.com
@EXAIR_BF