When we work with our customers about cooling applications, we usually approach them in one of two ways – either with a need to cool down to ambient temperatures, or a need to cool below ambient temperatures. If we only need to cool to ambient conditions, we can use Super Air Amplifiers, Super Air Knives, Air Nozzles, or Safety Air Guns. But, if we need to cool below ambient temperatures, we have to use a vortex-based technology such as a Vortex Tube, Adjustable Spot Cooler, Mini Cooler, Cold Gun, or Cabinet Cooler.
One of our overseas customers reached out to me with a need to cool a 400g aluminum plate from 80°C (176°F) to 27-30°C (80-86°F) over the course of about 40-60 seconds. They needed something repeatable, dependable, and compact, so we explored a Vortex Tube-based solution.
We’ve shown airflow calculations for our Air Amplifiers in the past, and I used the same rationale (shown above) to determine the required air volume to cool this application. In these types of applications, we derive a ΔT value between the desired ending temperature of the material and the temperature of the air which will be blown onto the material. So, for this application, we have a desired end temperature of 30°C, and we have considered an outlet temperature of 0°C from a Vortex Tube device.
After determining all the required values, I performed the calculations shown below to arrive at a volume flow of 15.8 CFM.
In uncovering that the ambient conditions may change, and sharing that these changes could create variance in the required air volume, the end user opted for two model 3925 Adjustable Spot Coolers to provide the required cooling. Just like Vortex Tubes or Cold Guns, the Adjustable Spot Coolers allow for repeatable delivery of very cold air to the application, but they also have the additional benefit of easy “fine tuning” through the adjustment valve on the hot end of the unit.
The cold air created by the Adjustable Spot Coolers are fed to the nozzles shown above in red. By supplying an adequate volume of cold air at the right temperature, the problem in this application has been easily solved.
If you have an application with a heating concern, give us a call. We’re happy to help.
Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE
A question about temperature differential. Why do you take the differential 30°C (from air supply) and not 50-53°C (from process)? Greetings
Hi Nahs,
We are considering a temperature differential between the desired temperature of the aluminum, and the temperature of the air which we will blow onto the aluminum. In this case, we have a desired temperature of 30C, and have considered a temperature of 0C for the outlet temperature from the Vortex Tube device, thus the delta T of 30C.
We must consider this differential rather than that of the process (50-53C), because we will remove the heat from the process and must determine the required air volume to maintain the desired temperature of 30C.
Feel free to email me with any questions at LeeEvans@EXAIR.com
Best regards,
Lee