Selecting a Packaged Standalone Chiller

By: Adam Wells (Solutions Engineer, Pfannenberg USA, Inc.)

 

When considering a liquid chiller system, precision and accuracy are critical for the temperature control of the application. Innovative cooling equipment is essential to regulate temperatures to ensure effective control. Find out how to select the best liquid chiller system for a given application by following the very important steps laid out here.

Calculate system size

Correct selection and sizing of the liquid chiller system for a given application can make a significant difference in reducing startup waste, achieving higher quality applications, increasing product output, and improving profitability. Calculating the size of the liquid chiller system using correct application details is critical to achieving accurate process cooling with a liquid chiller. Further, the size or capacity of a liquid chiller system must be designed to accommodate the varying workloads and ambient conditions that affect the system.

Performing sizing calculations

The three main factors for sizing are:

  • Incoming water temperature (°F) (also known as processed water temperature),
  • Required chilled water temperature (°F) (also known as the setpoint of the chiller), and
  • Flow rate (measured in gallons per minute, or GPM).

Understanding the liquid medium

Cooling processes can be handled with any one of three different mediums: water, water/glycol, or heat transfer oil. Which fluid type selected depends on the temperature the system must achieve, cooling loads, and process requirements like flow capabilities, cycle times, material, etc. In cases where pure water is not a usable medium for the application, glycol and heat transfer oil can be utilized partially to create a water-based emulsion. Cooling capacity correction factors must be made if glycol or heat transfer oil will be utilized.

Determine appropriate controls

Liquid cooling demands accuracy and reliability for temperature stabilization, while operators need easy-to-use and highly visible controls and indicating lights. Pfannenberg chillers offer microprocessor-based controls that provide control performance, visibility to operators, and are configurable to meet specific application needs. A variety of control features including flow/pressure alarms, ambient temperature alarms and remote communication options are available to ensure optimal and desired results.

Prolong the life of your liquid chiller system

Preventive maintenance procedures should regularly be performed to keep the liquid chiller system clean and well-maintained. Performing weekly, monthly, and quarterly checks will extend the life of a chiller system. Refer to the procedures provided in the manufacturer’s instruction manual. By following some basic guidelines before, during and after installation, users can extend chiller lifespan, avoid mechanical/electrical problems, and ensure that a liquid chiller system will provide a high level of efficiency and reliability throughout its lifetime.

Chillers for Industrial Automation and 3D Printing Applications

By Adam Wells, Solutions Engineer, Pfannenberg USA

In the last several years, the use of Industrial Automation and Industrial 3D Printing technology has increased seemingly exponentially. While these technologies confer major benefits in terms of efficiency, quality, cost, and lead times, they also present unique challenges in terms of protecting the sensitive electronic equipment from heat. The buildup of heat can degrade electronic devices used in these processes, thus reducing their life span and increasing total cost of ownership. These technologies require purpose-built industrial fluid cooling solutions; namely, they require chillers with streamlined design, built for a range of environmental conditions, and available on short lead times. Finding such chillers can be difficult.

Industrial fluid cooling equipment for Automation and 3D Printing environments

Rapid technological advancements over the last decade or so have dramatically increased the scope and prevalence of industrial automation and 3D printing technologies in industrial settings. Many packaging and manufacturing operations, in automotive, food and beverage, and more industries, are moving towards widespread adoption of these technologies in an effort to increase efficiency, reduce staffing needs, and improve quality. In the adoption of this technology, the demand for industrial chillers that meet the unique needs of automation and 3D printing machinery has undergone a similarly rapid period of growth. Chillers, as this article will discuss in greater detail, must be designed and sourced carefully in order to provide sufficient cooling in industrial automation and 3D printing applications.

First, I will set out a brief definition of terms to clarify the technologies this article is oriented towards:

  • Industrial automation is the use of control systems, robots, and/or information technologies to mechanize and control what has historically been human labor. Beyond simple mechanization, though, industrial automation, or IA, includes some level of autonomous process control. Examples of IA processes include CNC manufacturing, the use of robotic arms to construct and move products in manufacturing, and more.
  • 3D Printing is a specific automated process in which a physical object is constructed from a three-dimensional digital model, typically by laying down many successive thin layers of a heated and then extruded material. It brings a digital object (its CAD representation) into its physical form through a layered additive manufacturing process. Undertaken at a far larger scale than benchtop 3D printing for prototyping or hobby use, industrial 3D printing technology is a viable option for producing parts in large quantities at once, all from the same digital model.

In many cases, IA and industrial 3D printing requires the addition of chiller equipment to cool and protect electrical and mechanical components or to cool parts after manufacturing. Motors in CNC manufacturing and large robotic arms as well as motors and pumps in industrial 3D printers often require their own liquid water chillers. Similarly, manufacturing processes that utilize industrial 3D printing alongside other methods, like the printing of caps for aseptic milk containers, require chillers so that printed parts can be water-cooled for release from printing molds or before moving on to the next phase of manufacturing. In all of these cases, the chiller systems ought to be utilized with water handling systems that collect, filter, re-cool, and re-cycle water through the system in multiple cooling cycles.

Packaged chillers enable rapid project development and implementation

Industrial automation and industrial 3D printing are lauded for the benefits they confer on manufacturing processes: higher production rates, increased productivity, more efficient use of materials, better product quality, improved safety, reduced labor needs, and shorter factory lead times. As with all manufacturing methods, there are also challenges that accompany these benefits. One of the primary challenges manufacturers face is that since IA and 3D printing technologies are often implemented to increase speed and efficiency and thus reduce costs, all supplementary technology, like chillers, must also meet speed and efficiency demands. Often most challenging is shortening the initial lead time for acquiring these supplementary technologies. Manufacturers generally attempt to implement IA and 3D printing project as quickly as possible, to reap the benefits of increased efficiency, and so the 8-10 week average lead time for chiller equipment can be a major setback.

Pfannenberg, an industry leader in liquid cooling technology, has recognized the challenge that long lead times pose challenges for manufacturers looking to implement IA and 3D printing solutions in their production projects. Out of a concern for customers’ ability to solve challenges in an efficient manner, and to get projects up and running as quickly as possible, Pfannenberg has begun to offer stock delivery of chillers that are specifically designed for industrial settings like the ones needed for IA and 3D printing projects: low complexity, highly efficient, and with a high capacity-to-physical size ratio, these chillers deliver cost-effective cooling with no manufacturing and delivery lead time.

Pfannenberg’s CCE Series is an excellent example of packaged, off-the-shelf chillers available with little to no lead time. Typically featuring one to three tons of cooling, the CCE Series is ideal for the kind of small, industrial cooling most IA and 3D printing applications require. These chillers feature leading-edge fluid cooling technology, including newly redesigned condensers for more streamlined and efficient cooling operation. What’s more, they can be centralized, using a single chiller that serves multiple cooling needs, or decentralized where each application or machine has its own chiller. This enables manufacturers to tailor water and energy usage to specific process demands, and allows for greater flexibility in expanding production capacity over time.

Chiller design for harsh environmental conditions

Manufacturers must consider more than just lead time when selecting fluid cooling equipment for IA and 3D printing equipment, though. Some manufacturing and packaging environments, particularly those with more heavy-duty manufacturing processes, can pose additional challenges for chiller equipment. Though 3D printing tends to take place in slightly cleaner facilities, environmental conditions should always be considered before purchasing industrial fluid cooling equipment.

Industrial fluid cooling equipment should be designed to function well even in hot, dirty environments, and fluid cooling OEMs should work with manufacturers to determine the proper equipment and placement for that equipment in any given environment. Chillers in heavy duty manufacturing environments should be designed to withstand corrosion and buildup of dirt and grime. Pfannenberg’s chillers, for example, are powder-coated rather than painted to improve corrosion resistance, and include micro-channel condensers heat exchanger coils to resist grime buildup in dirty manufacturing environments. The chillers also feature a filter alarm to detect any decrease in performance due to air contamination.

In particularly dirty environments, or manufacturing facilities where the only available space for chillers in is a boiler room or other extremely hot environment, outdoor placement of chiller equipment may be indicated in order to maintain efficient operation. Outdoor placement is also indicated where chiller equipment may pose risks to personnel due to its loud operation or heat emission, or where size is of concern. These chillers, though, need additional environmental protections in order to be able to withstand rain, sleet, snow, sun, and more during outdoor operation.

Pfannenberg has developed the EB Series for higher-demand indoor or outdoor chiller operation; with capacities ranging from five to eight tons of cooling, these chillers are suitable for any outdoor conditions except for sustained extreme cold temperatures. While the majority of manufacturers rely on Pfannenberg’s chillers for a 10-20ºF temperature delta, the company’s engineers can also collaborate with manufacturers who have more significant cooling needs in either indoor or outdoor environments.

Conclusion

Industrial fluid cooling technology is a critical component to implementing industrial automation or industrial 3D printing systems in a wide range of manufacturing and packaging applications. In order for these IA and 3D printing projects to succeed, manufacturers need to be able to source efficient, reliable, and rugged chillers within extremely fast turnaround times. A departure from previous industrial chiller demands, the challenges faced in industrial fluid cooling for IA and 3D printing require purpose-built, leading edge, and packaged chillers that can be sourced quickly and relied upon for streamlined operation in a wide range of harsh environments.

Liquid Cooling For Induction Heating Processes

Using Chillers to Ensure the Maximum Cooling Capacity in the Smallest Possible Footprint

Traditional metal working practices are time consuming and inefficient. Heating equipment takes a lot of time and therefore also uses a lot of energy. The removal of heat is also necessary, however, in order to maintain structural rigidness as well as to solidify material in the welding process. Additionally, equipment designs need to ensure it is serviceable. Equipment requires frequent physical contact for maintenance. Safety is also a huge concern with traditional welding or heating processes.

Using Chillers in Induction Welding Processes

Convection alone cannot adequately maintain an acceptable operational air temperature when the ambient air temperature is very high. Therefore, an air-cooled liquid chiller is ideal for removing concentrated heat from process equipment. Induction solves many of the stated problems because it generates heat from within the object instead of an external heat source, saving energy and making it safer to use. Automated induction longitudinal welding is a reliable, high-throughput process.

Factors to be considered when choosing a system for cooling an induction process include cost, space availability, existing utilities, energy and water usage, equipment location, potential for freezing, reliability, and maintenance.

A smart controller in the cooling system will set the minimum and maximum water temperature with an alarm. Plus, a flow switch will trigger an alarm if the flow is too low, protecting equipment from being cooled. In addition, it will have a non-ferrous tank and piping to reduce corrosion and a thick powder coating on the stand-alone chiller, and reliable, easy-to-read fluid indication level readout.

Pfannenberg Packaged Chillers: Closing the loop for Industrial Fluid Cooling Applications

By using the proper temperature setting points, operators improve performance and increase the lifetime of devices. Highly efficient cooling technologies generate cost savings and preserve electrical equipment. Pfannenberg Inc. specializes in just this type of technology. Their air-cooled liquid chiller is ideal for removal of concentrated heat from your process equipment. Operators want to select chillers that have a small footprint for equivalent capacity which is offered in Pfannenberg Inc.’s product lines as well.

 

 

 

 

 

 

 

Pfannenberg’s chillers guarantee a central and economical solution and perfectly meet the need for precise temperature control and absolute reliability. Whether it is a compact or large chiller, maximum cooling capacity in the smallest possible footprint is guaranteed thanks to the heavy-duty micro channel condensers that offer high efficiency and long service life in hot, corrosive, or dirty ambient environments.

Click here to contact our Liquid Cooling Experts!

Pfannenberg Liquid Cooling Solutions for Industrial Electronics

Sealed enclosure cooling solutions ideal for extreme indoor or outdoor environments

Lancaster, NY – Pfannenberg, Inc., a leading global manufacturer of thermal management and signaling technologies, highlights its high-efficiency liquid cooling solutions for industrial electronics. Pfannenberg EB 2.0 Large Packaged Chillers and PWS Series Air to Water Heat Exchangers provide contaminant-free, cost-effective component cooling without adding heat to the local environment.

Closed-loop liquid cooling efficiently and economically improves performance for advanced manufacturing processes and electronics in hot, dirty environments using field-proven water circulation technology. Designed to guarantee full separation of water lines and airflow paths, Pfannenberg liquid cooling systems feature integrated electronic thermostats and flow control components for accurate temperature control and superior energy efficiency. Liquid cooling offers an ideal cooling solution for spindle motors and automation drives in automotive manufacturing, power plant electronics and solar inverters in energy production, and oven controls and product coolers/dryers in pharmaceutical production, as well as for paper & printing, plastic manufacturing, and water/wastewater applications.

EB 2.0 Large Packaged Chillers

Compact Pfannenberg EB 2.0 Large Packaged Chillers allow maximum cooling capacity in the smallest possible footprint. Heavy-duty finned-tube condensers deliver high efficiency and long service life in hot, corrosive, or dirty ambient environments.

Models range up to 30 Tons, so proper capacity is available for most applications, while all units are ready to use after simple installation—requiring only piping and power. Remote start/stop capability and insulated vented polypropylene reservoir tanks for rapid heat load changes provide reliable and flexible operation.

 

Check out Pfannenberg’s EB 2.0 Large Packaged Chillers Presentation Video

 

 

PWS Air to Water Heat Exchangers

PWS air to water heat exchanger

Pfannenberg PWS Air to Water Heat Exchangers deliver energy efficiency and high cooling capacity with a maintenance-free design for indoor and outdoor applications. Featuring a closed-loop design, PWS Air to Water Heat Exchangers seal contaminants out by isolating ambient air from the internal air circuit.

These units are ideal for extreme environments such as plant washdown areas, and areas with high amounts of particulate, high ambient temperatures, or an oily or aggressive atmosphere. PWS Air to Water Heat Exchangers maintain a UL Tested NEMA Type 12/3R/4 seal against enclosure, and a stainless-steel option offers NEMA Type 4X protection.

 

If a water source is not available on site, facilities can combine Pfannenberg PWS Air to Water Heat Exchangers with Pfannenberg EB 2.0 Large Packaged Chillers for an efficient closed cooling solution.

Visit the EB 2.0 Large Packaged Chillers page and the Air to Water Heat Exchangers page to learn more.


About Pfannenberg

Established in 1954 by Otto Pfannenberg in Hamburg Germany, Pfannenberg is recognized as a leading global manufacturer of thermal management technologies within the Electro-technology Industry. In 1958 we invented the Filterfan®, which continues to be recognized worldwide as a leading product to help manage the temperature in electrical enclosures. Our business philosophy: Protecting Man, Machine and the Environment.

Reliable Enclosure Cooling for Commercial Bakeries

Customer Requirement

Pfannenberg worked with a bakery end user to develop a cooling solution for their control cabinets.  Most of the OEM equipment installed in the bakery called for air conditioners to cool the drives. PLCs and additional electronics. Most times Cooling units can be a convenient and effective method for cooling electronics, except when located in dusty, humid areas within the plant.

These AC units failed regularly and had to be replaced. This was not a sustainable solution as the customer had constant issues with clogging coils and overheating panels.

Once a panel overheated they had to either: not operate the machine, or operate the cabinets with the doors open. This would let all the contaminants that were hurting the AC units into the cabinet, damaging the drives and other components.

The Pfannenberg Solution

To use the chilled Glycol that was already present for other machine processes to provide the cooled liquid source for our PWS Air to Water Heat Exchangers.

The solution included:

  • A reliable cooling solution designed for harsh environments
  • Reduced maintenance.  Once installed the units only have just one moving part, so regular maintenance is not necessary
  • Eliminating equipment failures, means greater uptime
  • Reduced energy costs with the PWS units
  • UL Tested NEMA Type 4/4X – washdown

Customer Benefits

Pfanneneberg’s PWS Series Air/Water Heat Exchanger was the precise solution for the problems our customer experienced. Incorporating Air/Water Heat Exchangers improved performance, reduced maintenance, was energy efficient, and prevented unplanned repairs.

 

Customer Success: Chiller Solution Saves Significant Water Costs for Ink Manufacturer

Choosing the best chiller for your application is not always as simple as picking a product from a catalog. When sizing a chiller it is important to know the environment it will be in. For example, if you need a 5 ton chiller you have to determine 5 tons at a certain ambient and a certain leaving water temperature. When you change either one of these parameters you change the capacity of a chiller. For instance a 5 ton chiller operating at 65°F leaving water temperature in an ambient of 90°F will become a 4 ton chiller if operating at 50°F leaving water temperature and 90°F ambient. The same holds true for higher ambient. The capacity will be reduced significantly when the ambient increases 10°F.

Application Example: EB Chiller Startup

Pfannenberg chiller experts went to perform a startup of a Packaged Chiller at a company that manufactures all different types of inks for printing. The application consists of 3 milling machines that grind raw pigment into liquid inks. The grinding process produces heat which must be cooled to maintain the process.

Customer requirements

The company was looking for a more cost effective solution as they were using city water to cool the milling machines. After the process was cooled this water went down the drain. Since the water was not reused in the process, the customer’s city water bill was extremely high and needed to be reduced.

Pfannenberg Solution

Pfannenberg packaged chillers achieve top grades in energy consumption.

  • First, properly sized chillers help to avoid extra costs, as an undersized chiller will never be able to properly cool your application while an oversize chiller will be inefficient due to excessive power consumption.
  • Then, a chiller is a looped system which uses a refrigeration cycle to remove  heat from a circulating liquid. As the liquid moves through a system of tubes and pipes it absorbs the heat generated by equipment and processes. This generated heat is then transferred by the liquid back to the chiller where it is dissipated. Fluid is cooled and sent back into the system which resulted in a significantly reduced water bill for the customer.

Customer Benefits
The Pfannenberg chiller and installation cost was 25% less than the city water bill leaving the customer with a ROI of 8-10 months.


Need help sizing a chiller? Nothing more simple! You can start by referencing our Chiller Sizing Guide, but if this is not enough to help you choose the best option for your application, you can use our new Chiller Quote Request Form. We’ve created this new web form to allow you to easily enter detailed information about your project, connecting you directly with one of our chiller experts.

CLICK HERE TO REQUEST A CHILLER QUOTE


Topics: liquid cooling

The 6 Step Guide to Choosing the Best Chiller for your Application

Heat is a single common by-product of today‘s manufacturing machines that include the advanced automation technology required for both high speed operation and high precision. Components such as spindle motors, variable frequency drives, laser and x-ray sources all require cooling to operate properly and reliably – most often in the very adverse manufacturing environments.

With manufacturing space at a premium, machine packages have become smaller and liquid cooling has emerged as the most efficient and economical means of removing process heat. Liquid cooling is especially well adapted to hot, dirty environments, where it provides a method of removing the heat from the machine and not contributing additional heat back into the environment.


A quick guide to choosing the correct chiller:

As each industrial environment is different, Pfannenberg designed a 6-steps guide to help you select the proper chiller for your application:

Step 1: Determine the Heat Load

It is important to determine the heat load of your application to ensure the chosen chiller is big enough for the intended application.There are several ways to determine the heat load (in BTU) but understanding the process is essential to calculating an accurate heat load.


Step 2: Determine the Coolant Type, Temperature & Flow Rate

When the heat load is known, the next step is to determine the coolant, its target temperature and the flow rate that the chiller must provide to the process. This is determined by the method from which the heat is transferred from the process to the coolant and the type of coolant being used. For example, water has different characteristics than oil.


Step 3: Identify Installation Environment

In what environment the chiller will be installed? Indoor applications for example can see high temperatures and dirty atmospheres, while outdoor installations can experience both low and high ambient temperatures. This can effect chiller sizing and require accessories such as air filters, sump heaters, etc.


Step 4: Use Chiller performance curves

Now use the chiller performance curves available to select a chiller model that meets or exceeds the required capacity based on the chilled water supply temperature and the highest expected ambient air temperature. Consideration should be given to the safety margin of the application with respect to available frame sizes to maximize the value of the chiller selection. Find all Pfannenberg Chillers Performance Curves on Thermal Management Catalog.


Step 5: Check Pump performance curves

Check the pump performance curves available to ensure that the pump will provide enough pressure at the design flow rate to satisfy the application. Some liquid cooled systems have small coolant flow paths or longer distances that can have higher than average pressure losses.


Step 6: Final Selection

Finally, consider that the remaining application requirements such as power characteristics, control options, footprint, agency listing, color, etc. are met by the selected standard Pfannenberg chiller. Choosing a standard chiller will bring you greater reliability, easier service with common spare parts and global support.

>> Click here to download the PDF version of this guide.


Pfannenberg offers a versatile range of packaged chillers, ranging in sizes from less than ½ Ton to 30 Tons insuring the proper capacity available for most applications. These packaged chillers are ready to use requiring only piping and power to install as part of your solution for process cooling applications – we‘ll even provide the coolant. Ethylene & Propylene Glycol coolants, with proper corrosion inhibitors are available in a variety of packaging options – both full strength and pre-mixed. Each chiller model includes the pump, tank, refrigeration system and controls required for simple installation and reliable, efficient operation.

Our knowledgeable applications staff is always on hand to discuss the application and to make sure that a proper selection is made. With our many available equipment options we can easily customize our standard chillers to meet specific application requirements.

Contact our engineering team for more information!

Pfannenberg EB Chillers: Tailor-made Solution for a Rail Component Manufacturer


Customer Requirement

A rail component manufacturer needed a solution to eliminate downtime caused from the overheating of their track drilling unit.  The current system used 2 undersized chillers, unable to keep up with the cooling requirements, especially when the ambient temperatures in the plant rose due to the hot afternoon sun.

The Pfannenberg Solution

An analysis carried out on location with the customer revealed that the cooling capacity of the two chillers no longer corresponded with the current requirements.  The cooling system needed to be redesigned.

Taking the temporarily intermittent high ambient temperature in the factory into account, the choice fell on our high performance EB 90 chiller.  This unit has an integrated control module which allows for precise temperature control of the cooling medium.EB_Chiller_drawing.jpg

The solution excels due to:

  • Separate cooling and hydraulic circuits
  • Control module to program small hysteresis of the oil temperature
  • Use at ambient temperatures of up to +40°C
  • Sturdy steel housing with thick powder coating

Customer Benefits

As a result of our plant audit, the customer was able to invest in a new solution that was tailor-made to meet their current needs instead of spending money on a temporary, expensive and insufficient repair of their old chiller system.  The new solution ensures the desired machine uptime even during those days affected by the hot sun.  A new maintenance contract was signed to support the optimum functionality of the equipment for the long term.


Have a question regarding which equipment is best for your application? Contact our engineering team for more information!


Pfannenberg, Inc. is a global manufacturer of Thermal Management, Liquid Cooling Solutions and Signaling Technologies.

Pfannenberg is proud to provide solutions as a single source to its customers. Our business philosophy – Protection for man, machine and the environment.

Need help sizing Chillers? Pfannenberg is here for you!

Do you have a need for liquid cooling? Do you have an old chiller that needs to be replaced? Are you unsure of your liquid cooling options? We are here to help!

Correctly sizing a chiller is crucial on many points. An undersized chiller will never be able to properly cool your application while an oversize chiller will be inefficient due to excessive power consumption.

To find the best product for your application you can start by referencing our Chiller Sizing Guide, but if this is not enough to help you choose the best option for your application, you can use our new Chiller Quote Request Form. We’ve created this new web form to allow you to easily enter detailed information about your project, connecting you directly with one of our chiller experts.

CLICK HERE TO REQUEST A CHILLER QUOTE


Pfannenberg is your expert source for liquid cooling products and helping you choose the correct chiller. We offer packaged chillers from fractional tonnage to over 30 ton. Need more capacity? We can talk about a modular design using multiple chillers. We can also offer installation and commissioning of your new Pfannenberg Chiller.

>> Click here for more information about Liquid Cooling Solutions!

Pfannenberg’s enclosure cooling units installed in the Gotthard Tunnel

Under construction for 15 years, the 35 mile long Gotthard tunnel located in Switzerland opened in 2016.

The Gotthard Base Tunnel impresses with many outstanding features:

  • It is the longest railway tunnel in the world at 57 km and its tunnel run, with all the transverse and connection tunnels, stretches over 154 km.
  • From 2016, passenger trains should have a top speed of 250 km/h, reducing the travelling time e.g. between Milan and Zurich to under 3 hours and should almost double the haulage capacity on the Swiss North-South Axis to 40 m tons of goods.

Operating a tunnel poses a huge challenge for engineers and operators. All products and solutions have to meet the highest requirements and have to work perfectly even under harsh ambient conditions. In particular, this applies to electrical enclosures and their thermal management, which are subject to extreme alternating pressure loads, temperature differences and are also exposed to dust and moisture.

In close collaboration, Swibox and Pfannenberg have developed a special climate control concept for tunnel applications. Robust Swibox electrical enclosures with a pressure body which was developed especially to protect the cooling circuit and the side mounted cooling units with integrated controller and heater from Pfannenberg guarantee a high system uptime which are situated, in the 176 cross passages amongst other places.

These electrical enclosure cooling units ensure that the thermal pressure of the electronic components integrated inside the electrical enclosures does not become too high and that they work safely and reliably throughout their whole service lives.

 

Electrical enclosures withstand every alternating pressure

The largest technical challenges were the high requirements to the system of protection of the electrical enclosure, IP65, and also the high alternating pressure load which is caused by the trains passing through. When entering the tunnel, the train pushes the air ahead of it, causing overpressure until the train passes by the cross passage where the electrical enclosures are standing. As soon as the train has passed, the overpressure transforms suddenly to a corresponding under-pressure.

All the electrical enclosures and the installed cooling units are exposed to the load of this alternating pressure of up to +/- 5 kPa. It had to be ensured that all devices can withstand this alternating pressure mechanically, simultaneously implementing the high system of protection.

It was possible to meet these requirements, thanks to the mechanical unit custom construction developed especially in cooperation with the company Swibox. This construction ensures a leak-proof separation of the surrounding (outer wall of the unit) and the inside of the electrical enclosure (unit inside), also under pressure load. A special feature here is the developed pressure body inside which the components of the inner cooling circuit are housed. Therefore, it was not enough to use reinforced sheet metal: the selection of a suitable material and the increased material thickness in combination with specially installed stiffening plates led to the desired compressive strength.

Climate control concept of electrical enclosures does not only mean cooling

Another challenge in tunnels is the ambient air. Large temperature differences ranging from -20 °C to +40 °C, maximum humidity of 100%, and ferrous abrasion of brakes, rails and contact lines in the ambient air increase the risk of corrosion and show how different a tunnel application is compared to standard applications.

Therefore, a special enclosure climate control concept had to be established for specifically this application. In addition to the cooling units, which are predominantly used inside the mountains (ambient temperatures up to +40 °C), Pfannenberg heaters also had to be installed in the portal sector (ambient temperatures to -20 °C). These heaters ensure that the temperature inside electrical enclosures does not fall below the so-called dew-point (the temperature that moist air has to drop to – by unchanged pressure – so that the amount of water dissolved in the air is precipitated as condensate). At the dew-point, the relative humidity is 100%; that means that the air is saturated with water vapour.

Pfannenberg’s new generation of controllers, designed especially for this project, were also installed. This is especially important to prevent unplanned failures and downtime and, by planning maintenance works in advance, to guarantee a high level of system uptime. The controllers are not only used directly inside the cooling units. The climate controller was also integrated into 500 other electrical enclosures without a cooling unit. This makes a temperature monitoring system possible, which, like the climate control units, can communicate with the tunnel control system and, if necessary, can be replaced with such, without having to reinstall the data transfer.

In 2010 the first cooling units were delivered to the company Swibox. In the meantime, all units have been delivered and will be installed one by one, together with the electrical enclosures, in the 176 cross passages of the Gotthard Base Tunnel. They have already been able to prove their reliability every day during the various test phases until the start of the scheduled railway operation on 2016.

Click here to read the full Case study!