© Ralf Kreuels

Here come the sound guys

The team of engi­neering consul­tants from Teensma makes sure things are quiet wher­ever noise would disturb people, including resi­den­tial areas with people who surf the Internet at high speed using fiber-optic connec­tions.

Given that Peter van der Velde actu­ally has nothing to do with venti­la­tion and air condi­tioning, he has put a lot of thought into them in the last few years. As the managing director of the Dutch engi­neering firm Teensma, he and his staff of six usually work to keep people from being both­ered by noise. Teensma insu­lates big indus­trial plants, improves acoustics in class­rooms, or makes sure that elec­trical instal­la­tions in resi­den­tial areas don’t disturb anybody with their humming.

An example is the distrib­utor stations for fiber-optic cables. They bring fast Internet access into the living room from the higher-level networks. The stations natu­rally have to be as close as possible to the users, but they shouldn’t make any noise. And this is where the air needed for cooling comes into play, the air that van der Velde has thought about so much lately.

Cooling with outside air

“Normal air condi­tioners are usually used to cool distrib­utor stations in resi­den­tial areas, but they’re often rela­tively loud and bother the neigh­bors. When we were tasked with making such a station quieter, first we devel­oped insu­la­tion for the existing instal­la­tion.

Small team, big job: The staff at Teensma make distributor stations for fast Internet in residential areas quieter. ( Photo | Ralf Kreuels)

Small team, big job: The staff at Teensma make distrib­utor stations for fast Internet in resi­den­tial areas quieter. ( Photo | Ralf Kreuels)

The result was a system that was quieter, but expen­sive to operate and so complex that only specially qual­i­fied tech­ni­cians could work on it. Since we as engi­neers prefer to think things through from the begin­ning rather than from the end, we set ourselves the goal of signif­i­cantly reducing noise at the source while also making the system design much simpler.”

So the team began work on a venti­la­tion system that would cool the equip­ment in the distrib­utor station using only outside air. This method had not yet been imple­mented success­fully in such distrib­utor stations and was viewed by many as insuf­fi­ciently reli­able. Van der Velde and his team worked mainly on the control system and the right filters for the venti­la­tion system; mois­ture and parti­cles must not be allowed to harm the sensi­tive equip­ment.

The engi­neers from Teensma were also very careful in their choice of fans, as van der Velde recalls: “From the begin­ning, we had ebm-papst and a competitor in mind for the required EC fans. We ordered prod­ucts from both compa­nies and tested them precisely in various instal­la­tion scenarios. The results were clearly in favor of ebm-papst. On average, its fans were four to five deci­bels quieter than the ones from its competitor. And the infor­ma­tion in the data sheets about air flow, pres­sure and noise level matched reality exactly. That may sound kind of trivial, but it’s defi­nitely not some­thing you can take for granted with a lot of manu­fac­turers. Some­times they’re a bit more opti­mistic with their values.”

80 percent less energy

The first proto­type with ebm-papst fans confirmed the engi­neers’ assump­tion that fresh-air cooling with EC fans would result in a bundle of bene­fits. Just a few steps away from the distrib­utor station, people no longer perceive its noise as disturbing. Due to their higher effi­ciency, the fans also give off less heat into the station’s inte­rior and reduce its energy consump­tion dras­ti­cally. The distrib­utor station with fresh-air cooling uses 80 percent less energy than its prede­cessor with a conven­tional air condi­tioner.

The data from ebm-papst are exact. That sounds trivial, but it’s not some­thing you can take for granted.

Peter van der Velde — Managing Director of Teensma

Beyond that, van der Velde can cite other advan­tages: “Venti­lating with fresh air is very simple. Main­te­nance staff need no special qual­i­fi­ca­tions. We can tell them every­thing they need to know in just a few hours. The system has fewer compo­nents, so it’s less likely to have malfunc­tions. Our product has been on the market for three years and there were only two malfunc­tions in that time, and they had nothing to do the fans. Another plus is control­la­bility. They can be adjusted to the exact output needed for the season and the temper­a­ture.”

Faster streaming

Teensma has sold over 300 distrib­utor stations to the Dutch fiber-optic network oper­ator Regge­fiber, and the German oper­ator Deutsche Glas­faser has bought over 100 stations. The product from the small Dutch engi­neering firm does its part in many areas to give people fast streaming, games and shop­ping without having a humming box in front of their houses. Van der Velde is opti­mistic about the future, saying “I see lots of poten­tial for our distrib­utor stations in the coming years. Fast Internet is often taken for granted in big cities, but there’s still a lot to be done in rural areas. With our quiet and simple systems, we make it easier to expand the networks, espe­cially in such regions.”

How the stations are cooled

Teensma packs all of a station’s equip­ment into a struc­ture made of concrete, which makes climate control easier due to its delayed heat absorp­tion and dissi­pa­tion. Teensma sells stations in two sizes. Depending on their purpose, they can be as large as a garage or a small shed. The smaller units can supply several hundred house­holds with a fiber-optic connec­tion; the larger ones can supply over 2,000.

To cool the elec­tronics in a station, RadiCal EC fans suck in cool outside air and convey it into the station under the floor. From there it flows into the room through a fine grill and cools the elec­tronics as it flows by. The resulting warm air then flows beneath the ceiling and back to the outside. Since the EC fans can be smoothly adjusted, the temper­a­ture in the distrib­utor stations remains below the stan­dard oper­ating temper­a­ture of the elec­tronics regard­less of the season and the ambient temper­a­ture.

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