Free Cooling for smaller telecom installations

Much attention is focused on large data centers. However, there is also an increasing need for smaller installations, which are closer to the local infrastructure. STULZ Benelux develops special cooling units that can be used in this context.

Text: Marcel Debets

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After the trend in recent years that increasingly consolidates data collection and processing in large data centers, a counter movement has now emerged. As EDGE computing and 5G require data processing to take place much closer to the end user, more and more compact facilities are built that must be able to handle data traffic locally. "These new situations require very different cooling solutions than we have been used to in the large data centers so far," says Richard Esendam, Business Development Manager Telecom & Infrastructure at STULZ Benelux. "We are talking about installations up to 30 kW. But while they may be smaller, these installations require just as much cooling." At the same time, there are new directives and standards, which in turn place additional requirements on the specifications of such cooling installations. "More and more often in tendering of telecom projects a reference is made to the ETSI EN 300 019 directive for cooling," Esendam explains. "And last year there was an addition to the 2012 Building Decree, which set new standards for the noise level of installations." There are quite a few applications that fall under these two directives, for example, high-voltage substations, traffic systems, railroad installations, but also telecom POP stations, street cabinets and 5G setups.

Free Cooling

In order to increase energy efficiency, reduce noise levels and nuisance from possible vibrations, STULZ is constantly looking for new cooling solutions. "We can find these in the use of so-called Free Cooling," Esendam explains. "In doing so, we deploy newly designed cooling units that draw in purified air from outside the facility in order to keep the temperature within the standard directives." This directive (ETSI EN 300 019) requires temperatures to be between 10 and 35 degrees Celsius for most of the year. No more than 10 percent of the year - about 876 hours - the temperature is allowed to be between 35 and 40 degrees, and 1 percent between 40 and 45 degrees. If it is not possible to keep the temperature between these values, then, if necessary, additional cooling can be switched on using a compressor, so-called 'forced cooling'.

Noise requirements

As far as noise standards are concerned, STULZ is bound by the legislation concerning outdoor cooling units/heat pumps. Because the telecom systems are often deployed close to residential areas, the maximum noise exposure is 40 dB at the property boundary. "And actually this has to be tightened by another 5 dB, because of the frequency of the sound, in order not to cause a nuisance," says Esendam. "That means you can forget about using standard outdoor units." STULZ is currently working on new cooling units that operate with 100 percent Free Cooling. These can meet the noise and temperature requirements, and are also much more energy efficient. Esendam wants to emphasize that you have to look at more than just the cooling. "Free Cooling also has an effect on the design of an installation, for instance;  How do you arrange the airflows? What air volumes are needed in the room? What are the limits on the inlet and outlet? These are issues that the contractor is usually not familiar with. STULZ can help in the design of these sites as a knowledge partner to make sure the right solution is developed. This is what we call ‘Climate.Customized’."