Tag: Temperature Sensing Labels

In modern industrial plants, electronic equipment is used for motor control, and most of not all machines are controlled by PLC’s. The high heat dissipation from electronic equipment exposes control systems to elevated temperatures that make them susceptible to malfunction if too hot, creating unpredictable behavior or failure that could lead to a plant shut-down.

Electrical enclosure temperatures are should be kept well below 106 ºF (41 ºC) to limit the possibility of severe damage to equipment. The heat load from electronic equipment limits the practical use of natural ventilation to cool the electrical enclosures resulting in the adoption of alternate methods.

Fans with Filters

The simplest and often lowest cost solution is to use fans to remove waste heat by circulating ambient air throughout the enclosure. This works provided the ambient air temperature is moderate if the enclosures are well shaded, and when the internal heat generated is low. Filters must be used to keep out dust and debris from the factory atmosphere and need to be cleaned and/or replaced regularly depending on the nature of the plant environment. Normally the cooler air is blown into the bottom of the enclosure, and exits “hot” at the highest point of the control panel. Fans must be sized to provide sufficient airflow to remove the heat generated by the electrical controls.

Again, the use is limited to electrical enclosures with relatively low heat loads, in shaded areas, and where the ambient temperatures are moderate. If the environment is very dusty and even if it contains a lot of oily mist, the replacement of filters can become quite a time-consuming and costly endeavor. This often results in filter neglect, which can create heat removal problems finally resulting in potential damage to the enclosure controls and downtime.

Air-to-Air Heat Exchangers

In difficult factory environments, with moisture, heavy dust is present, and oil or chemical vapor, the cabinet or panel enclosures must be sealed. One method is the use of closed-loop heat pipes.  A heat pipe absorbs the heat inside the enclosure and transfers it to the outside using a thermally conductive, phase-changing liquid under a partial vacuum.  Heat pipes are used extensively in laptops to remove heat from processors for example. Inside the enclosure, the liquid in the heat pipe absorbs heat and converts it to vapor. This vapor moves to the other end of the heat pipe which is outside of the enclosure, transfers the heat to the outside, and changes back to a liquid. The cycle repeats continuously with no moving parts, which makes air to air heat exchangers a relatively low-maintenance solution.  The only components that require electricity are two small fans outside of the enclosure to cool the hot ends of the heat pipes to begin the cooling cycle again.

Although relatively low cost and simple, the cooling application is again limited by the outside ambient temperature in the factory as you cannot cool to a temperature below ambient. Fans involved in cooling the heat pipes still require filters to prevent them from clogging and damage and again, if not replaced, can stop working causing the cooling system to fail.

Air-to-Water Heat Exchangers

If a chilled water supply is available, Air-to-Water Heat Exchangers can offer sub-ambient cooling. The internal components of Air-to-Water Heat Exchangers are normally completely encased within a sealed enclosure, thus providing maintenance-free closed-loop cooling. These systems are ideal for the dirtiest industrial environments where oil mist, dust, and dirt would quickly clog the filters of the earlier mentioned systems. Metal grinding and stamping, automotive brake plants, flour milling, and mining operations are all examples of very nasty environments where the applications for Air-to-Water Heat Exchangers can be applied. Similarly, food processing, especially meat and poultry processing plants where frequent wash-downs are normal, are ideal industries for their use.

A major issue is the quality of the water used. Scale buildup can be detrimental if water treatment is poor or nonexistent rendering such systems unable to remove the heat adequately. With zero discharge regulations in many jurisdictions, water itself is not low-cost anymore and downtime for descaling is a cost that needs to be considered. However, there are some excellent environmentally friendly, and safe descalers on the market such as Alpha Descaler for not only maintenance but also for regular treatment to prevent scale formation.

Air Conditioning the Enclosure

In harsh environments that are also hot and humid and where the enclosure heat loads are high the only workable option is an industrial-grade air conditioner. Traditional air conditioners using chemical refrigerant coolant are designed to work with sealed cabinets and prevent the drawing in of moisture, dirt, or other vapor from the environment. Capacities vary from 1,000 BTU to 20,000 BTU and models are available for standard NEMA 12 enclosures or NEMA 4 and 4X enclosures for harsh and corrosive environments. Options to prevent corrosion in corrosive environments and for outside use in rain and/or snow protection can be used. Due to increasing environmental regulations, new refrigerants have been developed and introduced which have increased the costs of traditional air conditioners along with their development. Costs increase also due to the changing of certain materials such as seals as old seals may be negatively affected by the new refrigerants. Some of these new refrigerants have flammability issues which can be addressed by design changes (again more costly) but have caused concern for their use in some facilities. And, they still have the issue of filter cleaning and/or replacement which – if not done, can cause damage to the air conditioner.

Increasing in use are vortex-tube operated air conditioners. While they require compressed air for use, they use no chemical refrigerant, are simple in design, have no condensate produced, are vibration resistant, keep out the harsh factory environment by slightly pressuring the control panel, and are virtually maintenance-free. There are no external filters as there are no fans to worry about and as long as the compressed air supply is kept clean with proper filtration for the compressed air, these types of air conditioners can work for many years with virtually no maintenance. They are also much more environmentally friendly with no refrigerants and have zero flammability issues. One interesting factor is that in very high-temperature ambient, you can utilize a smaller capacity vortex cooler than you would a traditional air conditioner because a vortex tube operated panel cooler performance is independent of ambient air temperature, unlike a traditional air conditioner. It only depends on the temperature of the compressed air itself. Many vortex coolers like the Nex Flow® Panel Cooler are available for NEMA 12, NEMA 3R (outside use) and NEMA 4-4X enclosures. Nex Flow® has also developed and continues to develop increasingly efficient cooling systems utilizing vortex tube technology and special systems can be made. This type of air conditioner is the most environmentally friendly and user friendly of any air conditioning method.

Enclosure Cooling and Reliability

Reliability is a huge issue in modern times with supply chain issues, lack of adequate labor, and concern over timely responsiveness when issues occur. The greater use of electronics in addition to higher enclosure packing densities has directed the use of enclosure cooling more toward air conditioners. Opting for systems that are better for the environment, and have minimal maintenance is a definite trend. Additional security in large factories is now provided by the installation of remote alarm systems, or by linking the digital controller to a remote web server that can simultaneously monitor several enclosures. This ensures that maintenance personnel is immediately notified of any malfunction to prevent unplanned incidents from becoming plant outages. In smaller operations, monitoring is still primarily by observation. One simple item to assist in monitoring for any heat problem in a control panel is a Temperature Sensing Label supplied with all Nex Flow Panel Coolers. It is placed outside the panel in one top corner and offers a visual indication of potential heat load issues that a passing employee can easily see and then act upon if necessary.

When costly electrical and electronic equipment that maintains the operation of a factory go down, production stops. Critical servers and security systems that drive production is of primary importance in a manufacturing operation not only for production but even for employee safety.

Maintaining the right temperature inside electrical and electronic cabinets require a reliable cooling system. Elevated ambient temperatures in a factory environment can cause costly system failure.

1. Reliable Cooling systems enhance the useful life of controls.  When temperatures rise above maximum operating levels, electrical component life can be reduced significantly. A reliable cooling system keeps the panel temperature below the manufacturer’s recommended maximum value, something simple fans and a building’s HVAC system cannot guarantee.

2. Employee Efficiency is increased. Any company wants employee time spent on improving the business and the bottom line, and not dealing with unexpected breakdowns. While the unexpected does happen those related to control panel shutdown can be reduced dramatically with a reliable cooling system.

3. An Ideal Air Conditioning Systems is Maintenance Free or at Least Minimal.  Most cooling systems require regular checks, such as filters on an air conditioned panel. If not changed regularly especially in a dirty environment one of two things can happen: if not changed a dirty filter can cause poor air circulation and overheating or, if the filter is missing, then dirt can get inside an enclosure and coat, and damage controls or at least reduce their lifetime significantly. Too often these things get missed or just ignored due to lack of maintenance time.

4. Prevention is Always Less Costly.  Preventative maintenance starts with machines working in a properly controlled environment. Just as people work better in a better environment, so does equipment. Poor temperature control inside electrical and electronic enclosures is damaging both economically and from a safety perspective. The use of an efficient cooling system is both economically more profitable and much safer to personnel.

Let’s go deeper on each of these points.

Reliability is becoming more important as labor costs and even labor shortage increase over time. It is important that ANY product for cooling is reputable both in quality as well for technical support should anything actually go wrong. But it’s more than just the supplier’s reputation. Any product chosen should consider the factory environment in which it is placed. Utilizing a fan to cool the inside of a control panel in a dirty and hot and humid environment without considering the environment in which the panel exists can invite trouble. The manufacturer of the control panel does not always have control or any say in which the panel is placed. If the environment is nasty then that should have a serious impact on the cooling method chosen.

Employee basic responsibility is to keep the plant operating. This means an acceptable preventative maintenance program and not only just responding when a problem occurs. If problems persist, the more thorough investigation should be made. Too often however, the problem is not addressed and much time and cost is spent fixing things over and over. For control panels, if the panel door is consistently “left open” because it’s just too hot inside the enclosure, then it should be addressed. It is not only unsafe to leave electrified enclosures open while operating, it is also in most placed illegal. Addressing these problems expeditiously can only improve the environment overall as well as reduce downtime and other potential problems.

Labor costs are significant in any production operation and labor efficiency is important. Every time an outside service person is brought in, some employee must escort that person in the factory, perhaps spend time while that person goes thru a safety protocol training and of course, there is downtime when maintenance is done. Even if no outside person is needed for service, there is still a downtime cost when maintenance is performed by employees. If labor cost can be optimized by reasonably priced solutions that are relatively maintenance free, it should be done.

Prevention is helped by a properly maintained preventative maintenance program and can be further improved by monitoring. There has been and continued=s to be tremendous advances in monitoring of all sorts of equipment especially rotating equipment such as pumps and motors. But what about control panels? While so much is spent for monitoring other equipment the electrical and electronic enclosure should not be ignored. It is just as important in any production line since it keeps that motor or pump running!

HERE IS A NEX FLOW®SOLUTION especially ideal for hot and dirty environments:

We suggest the Nex Flow® Frigid-X® Panel Cooler

They are:

1. Reliable as they do not require electricity to function,
2. Free up Employee Time due to its reliability
3. Essentially Maintenance Free with no filters to change or worry about and even keeps control panels clean by keeping out dirty plant air, and
4. Prevents Downtime due to Overheating by maintaining the proper environment inside a control panel.

Every Panel Cooler comes with a Temperature Indicator sticker that you can put on the outside of a control panel to indicate if the approximate temperature inside the enclosure. Extra stickers can be purchased for other panels. Monitoring does not always need to have a high cost.