For most industrial enclosure cooling applications, a temperature of 95°F (35°C) is sufficient to be below the rated maximum operating temperature of the electrical components inside the cabinet. EXAIR Thermostats are preset to 95°F (35°C) and are adjustable. Maintaining the cabinet at 95°F (35°C) will keep the electronics cool and provide long life and reduced failures due to excessive heat. But if 95°F (35°C) is good, why not cool the cabinet to 70°F (21.1°C)?
When cooling an enclosure to a lower temperature, two things come into play that need to be considered. First, the amount of external heat load (the heat load caused by the environment) is increased. Using the table below, we can see the effect of cooling a cabinet to the lower temperature. For a 48″ x 36″ x 18″ cabinet, the surface area is 45 ft² (4.18 m²). If the ambient temperature is 105°F (40.55°C), we can find from the table the factors of 3.3 BTU/hr/ft² and 13.8 BTU/hr/ft² for the Temperature Differentials of 10°F (5.55°C) and 35°F (19.45°C). The factor is multiplied by the cabinet surface area to get the external heat load. The heat load values calculate to be 148.5 BTU/hr and 621 BTU/hr, a difference of 472.5 BTU/hr (119.1 kcal/hr)
The extra external heat load of 472.5 BTU/hr (119.1 kcal/hr) will require the Cabinet Cooler System to run more often and for a longer duration to effectively remove the additional heat. This will increase, unnecessarily, the operating costs of the cooling operation.
The other factor that must be considered when cooling an enclosure to a lower temperature is that the Cabinet Cooler cooling capacity rating is effected. I won’t go into the detail in this blog, but note that a 1,000 BTU/hr Cabinet Cooler (rated for 95°F (35°C cooling) working to cool a cabinet down to 70°F (21.1°C) instead of 95°, has a reduced cooling capacity of 695 BTU/hr (174 kcal/hr). The reduction is due to the cold air being able to absorb less heat as the air rises in temperature to 70°F instead of 95°F.
In summary – operating a Cabinet Cooler System at 95°F (35°C) provides a level cooling that will keep sensitive electronics cool and trouble-free, while using the least amount of compressed air possible. Cooling to below this level will result in higher operation costs.
If you have questions about Cabinet Cooler Systems or any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.
High Temperature – For enclosures that reside in high temperature ambient conditions such as near furnaces, boilers, or ovens, EXAIR offers a High Temp version, with special internal components designed to withstand the elevated temperatures. Cabinets near sources of high heat certainly need to be kept cool, and the EXAIR High Temperature Cabinet Cooler is specially suited to for use in these locations.
Non-Hazardous Purge (NHP) – Cabinet Cooler Systems with this feature provide a continuous positive purge within the enclosure to prevent contaminants from entering through small holes or conduits. Especially suited for dirty and dusty environments, the NHP Cabinet Cooler Systems provide a slight positive pressure inside the enclosure. This is done by passing 1 SCFM (28 SLPM) of air through the cooler when the the solenoid is in the closed position. When the thermostat reaches the set-point temperature and energizes the solenoid, the full line pressure of air is delivered to the Cabinet Cooler providing the full cooling capability, and still keeping the positive pressure. When the internal temperature cools to the set-point, the solenoid closes and the system returns to the 1 SCFM (28 SLPM) of air flow condition.
Type 316 Stainless Steel NEMA 4X Cabinet Coolers – For enclosures that are in food service, pharmaceutical, harsh, and/or corrosive environments, and any application where 316 stainless steel is preferred, the Cabinet Coolers are available in the Type 316 stainless material. The systems are UL Listed for wash down environments, ensuring the enclosure electrical contents remain cool and dry under any condition. Noted applications include on ocean going ships, power plants, medical device manufacturing facilities, and bakeries.
Please note that the High Temperature, Non-Hazardous Purge and Type 316 Stainless Steel Cabinet Coolers are each available from stock! No waiting for these special models.
We here at EXAIR always know when summer is approaching, as phone calls and orders for the Cabinet Cooler Systems start to kick into high gear. After those first few hot days in late spring, it is common for panels and electrical enclosures to overheat due to faulty air conditioning units, fans that are not working, or lack of a cooling system in general.
Time for us to sharpen our pencils and be ready to help! Our Cabinet Coolers are in stock and ready to solve your overheating problems with same day shipping on orders we receive by 3pm. If you need assistance choosing your Cabinet Cooler Solution, Contact an Application Engineer today!
The Cabinet Cooler System is a low cost, reliable way to cool and purge electronic control panels. We recently hosted a Webinar on the systems, and it is available for review (click picture below)
EXAIR Cabinet Coolers incorporate the vortex tube technology to produce cold air from compressed air, all with no moving parts.
Below shows the basics of how the Cabinet Cooler is able to provide cooling to an enclosure. Compressed air enters the vortex tube based system, and (2) streams of air are created, one hot and one cold. The hot air is muffled and exhausted through the vortex tube exhaust. The cold air is discharged into the cabinet through the Cold Air Distribution Kit and routed throughout the enclosure. The cold air absorbs heat from the cabinet, and the hotter air rises to the top of the cabinet where it exits to atmosphere under a slight pressure. Only the cool, clean, dry air enters the cabinet – no dirty, hot humid outside air is ever allowed into the cabinet!
EXAIR offers Cabinet Cooler Systems for cabinets and enclosures to maintain a NEMA rating of NEMA 12 (dust tight, oil-tight), NEMA 4 (dust tight, oil-tight, splash resistant, indoor/outdoor service) and NEMA 4X (same as NEMA 4, but constructed of stainless steel for food service and corrosive environments.
Cabinet Cooler Systems can be configured to run in a Continuous Operation or with Thermostat control. Thermostat control is the most efficient way to operate a Cabinet Cooler. They save air by activating the cooler only when the internal temperature reaches the preset level, and are the best option when fluctuating heat loads are caused by environmental or seasonal changes. The thermostat is preset at 95°F (35°C) and is easily adjusted.
Another option is the ETC Electronic Temperature Control, a digital temperature control unit for precise setting and monitoring of enclosure conditions. An LED readout displays the internal temperature, and the use of quick response thermocouple provides real time, accurate measurements. The controller has easy to use buttons to raise or lower the desired cabinet temperature set-point.
Other Special Cabinet Cooler considerations are:
High Temperature – for ambient temperatures of 125°F to 200 °F – for use near furnaces, ovens, etc.
Non-Hazardous Purge – ideal for dirty areas where contaminants might normally pass through small holes or conduits. A small amount of air (1 SCFM) is passed through the cooler when the solenoid is in the closed position, providing a slight positive pressure within the cabinet.
Type 316 Stainless Steel – suitable for food service, pharmaceutical, and harsh and corrosive environments.
If you have any questions about Cabinet Coolers or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
Last week I wrote about the Thermostat Options for Smart Cooling utilizing the EXAIR Cabinet Cooler Systems. You can see read that blog post here. Today we will touch base on the Side Mount Kits as an option to expand the flexibility for the installation and operation.
Sometimes there isn’t room above an electrical panel to fit the Cabinet Cooler, even though it takes just 5″ to 7.25″ of space above. In these cases, the Side Mount Kit is available to handle any of the Cabinet Cooler sizes and NEMA ratings. EXAIR offers (6) models of Side Mount Kits –
Model 4909 – For NEMA 12 Cabinet Coolers up to 550 BTU.hr (139 Kcal/hr), Aluminum construction
Model 4910 – For NEMA 12 Cabinet Coolers , 650 BTU//hr (165 Kcal/hr) and higher, Aluminum construction
Model 4906 – For NEMA 4 and 4X Cabinet Coolers up to 550 BTU/hr (139 Kcal/hr), Type 303 Stainless Steel
Model 4907 – For NEMA 4 and 4X Cabinet Coolers, 650 BTU/hr (165 Kcal/hr) and higher, Type 303 Stainless Steel
Model 4906-316 – For NEMA 4 and 4X Cabinet Coolers up to 550 BTU/hr (139 Kcal/hr), Type 316 Stainless Steel
Model 4907-316 – For NEMA 4 and 4X Cabinet Coolers, 650 BTU/hr (165 Kcal/hr) and higher, Type 316 Stainless Steel
The NEMA 4 and 4X Cabinet Coolers must be mounted vertically for the unit to properly resist the ingress of liquids and maintain the integrity of the cabinet NEMA rating.
The Side Mount Kits install into a standard electrical knockout (1-1/2 NPS) for easy installation.
If you have any questions about the Side Mount Kits, Cabinet Coolers and/or Thermostat Options or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
If you watched the Webinar we hosted recently (if not, Watch It here) then you know that the EXAIRCabinet Cooler System is an intelligent solution for electrical enclosure cooling. The use of a Thermostat Control system is a key component to a system that provides the needed cooling while keeping compressed air usage to a minimum. There are several choices available, and I will cover those for you today.
The thermostat control systems are the most effective way to operate a Cabinet Cooler. They work by activating the the cooler only when the internal temperature of the enclosure reaches a preset, critical level. Thermostat controlled cooler systems are the best option when a cabinet will experience fluctuating heat loads, caused by operational, environmental, and seasonal changes.
Cabinet Cooler Systems that are ordered from the factory with thermostat control include a solenoid valve and thermostat. The solenoid valve is available in 110-120VAC, 50/60 Hz, 240VAC, 50/60 Hz, and 24VDC and is UL Listed and CE and RoHS compliant. The thermostat is rated for 24V-240V AC or DC, 50/60 Hz and is UL Recognized and CSA Certified.
The thermostat is factory set at 95°F (35°C). It will typically hold an internal cabinet temperature to +/- 2°F (1°C). The thermostat can be adjusted up or down if a different internal temperature is desired by turning the slotted temperature adjusting sleeve, with a 1/16 turn being approximately a 5°F change.
The solenoid and thermostat components are rated to match and maintain the Cabinet Cooler System and cabinet NEMA rating, and can be NEMA 12, NEMA 4 or NEMA 4X. A Thermostat Control can be added to an existing Continuous Operation Cabinet Cooler System, please consult the factory for help in selecting the right kit.
If you have any questions about the Cabinet Coolers and Thermostat Options or any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.
A casting company used a die casting process to make large aluminum panels. In their operation, a two-part die would clamp together and be filled with hot liquid aluminum. Once the panel was formed and cooled, the die would open to release the part. Before the next panel was die casted, they would use a home-made cart to cool and clean the dies. The cooling was done first by spraying water onto the surface, then compressed air was used to dry the dies. When they started to use their home-made cart in their process, they noticed that the air pressure would begin to drop in their facility. Other locations in the plant started having problems with their pneumatic equipment. They were using too much compressed air during the drying period; so, they contacted EXAIR to see if we could help reduce the amount of compressed air to dry the dies.
To explain a little more about the home-made cart, it was made from a 1” square piece of tubing that was bent in a U-shape. The dimension of the cart was about 40” long and 24” high. Across the top was a piece of extruded aluminum spanning the two ends of the U-shape tubing. This portion of the cart would supply the water to the liquid nozzles. The liquid nozzles hung vertically down from the extruded aluminum at designated heights to target certain areas of the dies. The U-shaped square tubing was used to supply the compressed air to the blow-off nozzles. The compressed air inlets were welded onto each end of the 1” square tubing. Across the bottom of the cart, the 1” square tubing had 38 holes that were drilled and tapped to 1/8” NPT (19 tapped holes on each side). The blow-off nozzles were 1/8” pipes with the ends smashed (reference picture below). They were made to different lengths to get as close to the die for maximum blowing force. The entire home-made assembly was attached to a robotic fixture with a cam to move the large cart between the dies. In applications using “smashed” pipes, they are very easy and inexpensive to make. But, as this customer found out, they use way too much compressed air and they are not as effective in blowing-off or drying.
The customer above was limited to modifications to the home-made cart. It was already configured with the robot features and cam to hit the targeted areas. So, I recommended the model HP1126, 1” High Power Flat Super Air Nozzle. It has a 1” wide air stream that is very similar to the flow pattern of the 1/8” smashed pipe. But unlike the smashed pipe design, the model HP1126 nozzle can accomplish so much more. One of the biggest differences is that the EXAIR nozzles use much less compressed air. (The initial reason for contacting EXAIR). With the engineered design of the nozzle, it can entrain large amounts of ambient air which means that less compressed air is required. For a 1/8” NPT smashed pipe, it can use close to 70 SCFM of air at 80 PSIG – each!
The model HP1126 only requires 17.5 SCFM at 80 PSIG. That is a difference of 52.5 SCFM per nozzle. With 38 nozzles being used on this home-made cart, that equates to a total savings of 1,995 SCFM of compressed air. By simply replacing the 1/8” smashed pipe to a model HP1126 with a shorter nipple, their facility was able to save much compressed air and maintain the pneumatic requirements in the other work areas.
The customer was extremely happy with the air savings, but they asked about the amount of force that the model HP1126 can supply. It was important in their process to remove any residual water from the dies. The reason for the blow-off pipes to be so close to the die was to try and increase the blowing force. The best way that I could explain to them was by using an example of a garden hose. (Reference a blog by Neal Raker “Sometimes Back Pressure is Good; Sometimes it is Bad“). The garden hose is attached to a spigot outside your house. As you open the spigot to supply water through the hose, the water will flow out of the hose at a slow velocity; not very strong. When you place your thumb partially over the end of a garden hose, you restrict the flow and increase the force. Now, you can reach the second-floor windows of your house to clean. With a lack of restriction at the end of the pipes, the air pressure will drop quickly as it travels through the long square tube and through the 1/8” pipe extensions. By the time the compressed air reaches the blow-off site, the pressure is much lower; thus, reducing the effectiveness of removing the water.
The EXAIR nozzles work like your thumb on the hose. The usable pressure is increased at the HP1126 nozzle, instead of a point much further upstream. By increasing the pressure at the point-of-use, the effective velocity and force is much stronger. In addition to this, they can now move the nozzles away from the die surface; in case of any “hiccups” in moving the cart in and out of the dies and eliminating any marring of the surfaces.
Once they installed the 38 pieces of the model HP1126 nozzles onto their cart, the first thing that they noticed was the amount of noise reduction. The model HP1126 only has a noise level of 82 dBA at 80 PSIG, compared to a noise level of an open pipe which is over 100 dBA. By replacing the flattened nozzles with the EXAIR nozzles, this company was able to…
1. reduce air consumption
2. keep the other areas of the plant operating by conserving compressed air at this location
3. reduce the noise level and
4. increase the effective blowing force
If you find that by using your blow-off/drying system, your pneumatic machines under-perform, or the low-pressure alarms are triggered, or you have to turn on an auxiliary compressor, you should contact an Application Engineer at EXAIR to see if we can optimize your compressed air devices. These EXAIR engineered nozzles can remove many issues in your system as it did with the casting company above.
The photo above shows a stainless steel Cabinet at left which has been installed near to a steam exhaust (within 1 meter) in a beverage manufacturing plant.
Inside the panel is a 150 mm diameter fan which is pulling in an air and steam mixture which is causing the temperature inside the cabinet to climb to unacceptable levels. The result is that the motor drives located inside the panel are failing, causing a tremendous cost for replacement and downtime.
Our local distributor worked with the customer to acquire the necessary data for us to calculate heat load within the panel. We determined the customer needed our model HT4880SS-240 Cabinet Cooler System to keep their internal panel temperature at a more reasonable level, year round, even in their worst case scenario with constant steam exhaust in the area.
One key component to success in this application will be removal of the fan and covering of the vent that it once occupied in order to keep the steam from being drawn into the inside of the panel. Historically, fans have been the go to strategy for keeping panels like this cool. However, in this situation, as in many others, the fans pull in un-wanted contamination. There isn’t any filter that can keep steam from getting inside and causing all sorts of problems with condensate forming on internal components, thus promoting corrosion and heat related failures.
The Cabinet Cooler System will provide a filtered, and dry source of cooling airflow which will produce a slight positive purge pressure on the panel to keep such harmful outside atmospheres from entering into the panel. This assures, long life for the panel components and much less hassle and problems associated with heat related failures.
Neal Raker, International Sales Manager firstname.lastname@example.org EXAIR_NR