Drives & Controls Magazine November/December 2022

42 n CONTROLGEAR AND ENCLOSURES November/December 2022 Are cooling systems worthwhile for smaller enclosures? D iehl Controls, based inWangen in Germany, manufactures products such as electronic subassemblies for domestic appliances.“Energy efficiency is one of our key priorities and an integral part of our strategy,”says the company’s value streammanager, Stefan Wespel.“We look for ways to improve energy efficiency in every new system and production line.” One way to save energy in manufacturing processes is to use high-efficiency enclosure- cooling systems. Although such systems have been available for large enclosures for many years, they have recently become available for smaller enclosures too. Diehl decided to conduct trials at its manufacturing site to see whether the smaller systems could match the efficiencies of the larger systems. One of the new systems has been in use in the company’s manufacturing workshop since the summer of 2021. Engineers fitted electricity meters to both the new system and to an older one to record the power consumption over a period of months. “During the first six months, the new cooling unit consumed 60% less electricity than the older unit being used for the comparison,”Wespel reports. Extrapolating this figure to cover an entire year suggests that the energy savings could amount to around €140 (£121) per cooling system. He describes this as “a fantastic result”. Because the smaller cooling systems could be used in large numbers, the potential cumulative savings are substantial. The new cooling systems – members of Rittal’s Blue e+ S family – combine a heat pipe with inverter-controlled compressors and fans. The heat pipe works without a compressor, expansion valve or other regulating elements, and does not consume any electrical energy. Depending on the heat in the enclosure that needs to be dissipated, and the ambient temperature, cooling can sometimes be achieved using the heat pipe alone. It’s only when large amounts of heat need to be removed from the enclosure or when the ambient temperature is unusually high, that the additional cooling compressor kicks in. This is claimed to be much more energy- efficient than conventional hardware, too. The inverter controls the compressor and fan, tailoring their speeds to suit the heat levels. Not only is there less cooling hysteresis, but energy efficiency is said to be much better, as well. The new systems use a coolant with a GWP (global warming potential) that is 56% lower than those used in other cooling systems. Instead of the R - 134A refrigerant which has been used previously, the new compressor uses R - 513A. This can be important if the coolant leaks and escapes into the environment. An interface built into the new cooling systems can link them to Rittal’s Smart Service Portal, allowing them to be monitored “intelligently”. The data gathered can be used to implement predictive maintenance and to optimise service processes. It can help to avoid costly unplanned downtimes. A strip of coloured LEDs indicates the status of the cooling systems. A display on the front shows other information. Also built in is NFC (near field communications) technology, allowing mobile devices running the Rittal Scan & Service app to communicate with the system. At first glance, reducing the energy consumption of small enclosures may not appear to be particularly significant in terms of potential energy savings in large industrial plants. However, because of the large number of smaller enclosures used in a typical plant, their combined potential to cut energy consumption and costs can be considerable. “Even if this application may appear to be no more than an ancillary process, there’s often hidden and unexpected potential here,” points out SteffenWagner, Rittal’s head of product management. The smaller enclosure cooling systems are available with capacities of 300, 500, 750 and 1,000W. n Cooling systems for large enclosures are a well-established technology that can achieve energy savings of around 75%. But is it worth applying similar systems to smaller enclosures? A German electronics manufacturer has been finding out. Adding cooling systems to many small enclosures can result in big cumulative savings – especially at a time of high energy prices