Recently, a customer considering one of our Cabinet Cooler Systems for his electronics panel had concern about the size of the existing compressed air line that was available. Following is a transcript of our discussion.
RE: EXAIR Cabinet Cooler model HT4325 (High Temp NEMA 12 Cabinet Cooler System, 1700 Btu/hr., with 120 VAC thermostat control)
What do we need for PSI to run this cooler (model HT4325 High Temp NEMA 12 Cabinet Cooler System, 1700 Btu/hr., with 120 VAC thermostat control), right now we have a ¼ line, not sure if we have the pressure to run this system.
Our Cabinet Cooler System cooling power specification is given with 100 PSIG inlet pressure. The Cabinet Cooler Systems can operate at lower input pressures, but the effective cooling power is also reduced accordingly.
Regarding your question about air line size; it depends on exactly what you mean by ‘¼ line’. Also, it isn’t just pressure, but also volume that is a concern. If you mean ¼ NPT pipe that is less than 25 ft from the main compressed air header pipe, then that would be sufficient. If you mean ¼” hose or ¼” tube, those will not be sufficient to power this specific product.
Under-sizing compressed air lines just like attempting to breathe under water with one of those little coffee stirring straws. It simply doesn’t have the capacity to flow the air volume needed efficiently and effectively due to the small cross-sectional area. The result is a “choked flow”. Again, refer to the coffee stirring straw analogy. You would be choking for air almost immediately.
In my experience, it is amazing how many folks let a $10.00 hose hold them up from implementing what could be a game changing solution for their application. Hose / pipe is not so expensive that it could not easily be up-sized to the proper diameter (1/2” ID hose or larger, depending on distance). If you double the hose diameter, you quadruple the cross-sectional area through which the air volume can flow. And it isn’t going to cost you any more in compressed air because the cooler self regulates with thermostat control to use only the air it needs to maintain target temperature inside your panel. Don’t let up-sizing the existing line be a hindrance to your progress. It is not a matter of using more air. It is a matter of using the air you need more effectively by eliminating power robbing pressure drops. So why not give the Cabinet Cooler a fighting chance of success by plumbing properly? If it was an electrically operated product, you would not give a second thought to using the proper size circuit breaker and wire gage, would you? The same rationale should be applied to compressed air lines as a properly sized air line will make the difference between success and failure. This kind of thought process holds true for any kind of pneumatic device whether an air nozzle, a Line Vac conveyor, or a Reversible Drum Vacuum System.
We want to do everything we can to help educate customers on the background issues which affect product performance as much as we can for obvious reason. If you have any further questions, please let me know.