EXAIR Cabinet Cooler Systems are a durable & reliable way to protect electrical enclosures (and the components they contain) from heat damage. All you need is compressed air…

…and as long as the cooling capacity of the Cabinet Cooler System is equal to or greater than the heat load of the enclosure, everyone’s happy, right?
Well, almost. I mean, it’s great that the vital components inside the enclosure aren’t getting too hot, but if it’s getting colder than it needs to be inside, then you’re using compressed air when you don’t have to. And compressed air is EXPENSIVE.
If you’re talking to an EXAIR Application Engineer about panel cooling, we’re going to talk about Thermostat Control too. We have two options for that:
Thermostat Control consists of a bimetallic probe-type Thermostat, spliced in to the ‘hot’ lead of a Solenoid Valve that’s plumbing into the compressed air supply of the Cabinet Cooler. These come preset at 95°F (35°C), which is based on the 104°F (40°C) temperature limit published by many manufacturers of electrical & electronic components. The setpoint temperature CAN be lowered (at the factory or in the field) if any particular component(s) need a cooler environment to operate in. It can also be raised, if everything in the enclosure can handle a higher temperature. THAT can save a good amount of compressed air (which, again, is EXPENSIVE.)
Operation is pretty simple: when the temperature starts to rise inside the enclosure, two dissimilar metal strips that are bonded together inside the thermostat start to thermally expand. Because they’re made of different metals, they expand at different rates, which makes the strips bend until they contact. This completes the electrical circuit to the Solenoid Valve’s coil, opening the valve to start operation of the Cabinet Cooler. As the temperature subsides and cold air flows into the enclosure, the two metal strips contract & straighten out, detaching the strip and the contact, which causes the Solenoid Valve to close, until temperature rises to the setpoint again.
EXAIR’s ETC Electronic Temperature Control provides the same function, but with some notable advantages:

- A Type J Thermo couple is wired to a solid state temperature controller to sense & control the temperature. It’ll hold +/- 1°F of the setpoint temperature, as opposed to the +/-2°F accuracy range for the bimetallic Thermostat.
- The LED readout provides constant indication of the temperature inside the enclosure. Personnel can verify, at a glance, that proper cooling is being applied. This is of great benefit to users who regularly monitor & log readings like this on enclosures with critical equipment inside, like nuclear power plants.
- Push button control allows for on-the-fly adjustment of the setpoint temperature. This, along with the +/-1°F accuracy range, allows users to precisely set the desired temperature to a point just slightly under the maximum rating for the electronics, which, as mentioned above, can result in a reduction in compressed air consumption and hence, operating cost.
- There’s also a calibration offset feature, which is handy if the Cabinet Cooler System is being installed on an enclosure with other temperature sensing equipment. This uses the push button controls to match the displayed temperature on the ETC to that of the existing equipment. It can also be used to verify the calibration of the ETC, which is another great benefit to users responsible for maintaining critical equipment.
As an EXAIR Application Engineer, it’s my goal to help you get the most out of our products, and your compressed air system. A big part of that is making sure you don’t use any more compressed air than you have to. If you’re ready to start saving, give me a call.
Russ Bowman, CCASS

Application Engineer
Visit us on the Web
Follow me on Twitter
Like us on Facebook










