ABB helps enhance Spanish indoor skydiving facility with variable speed drives |

ABB helps enhance Spanish indoor skydiving facility with variable speed drives

ABB helps enhance Spanish indoor skydiving facility with variable speed drives

By Jose Manuel Collados, Robotics and Motion Division Manager, ABB

When you want wind speeds stronger than a Class 5 hurricane to deliver a thrill without the danger of the real thing, you need technology that delivers precise control. The Windoor Realfly vertical indoor wind tunnel in Empuriabrava uses variable speed drives (VSDs) to control the fans that generate winds of 150-300 km/hour. The response of ABB’s four ACS800 VSDs is therefore crucial.

Every year, more than one million people flock to the indoor wind tunnel in Empuriabrava, in the northernmost part of Spain’s Costa Brava, which is the venue for the annual ‘Wind Games’, the unofficial indoor skydiving world championships. Indoor skydiving is a rapidly growing sport which allows participants to skydive for long periods of time due to a controlled environment without the vagaries of outdoor air movements and weather.

Windoor’s success can be attributed to its location and the customer experience it offers. The location is unique, being just a 30-second walk away from Skydive Empuriabrava, an outdoor skydiving zone. This enables Windoor to attract experienced skydivers who use the wind tunnel to hone their skills outside of outdoor flying hours. It is also a popular leisure activity for holidaymakers.

Windoor’s marketing manager Sergi Ponsa explains how crucial reliable fan speed is with more than one hour of downtime for the tunnel incurring severe costs in terms of compensation to customers who have missed out on a scheduled experience, not to mention reputational damage. “We need to offer a first-class customer experience that keeps people coming back time and again. Therefore, the wind tunnel must keep operating day after day, all year round, without missing a beat, sometimes working from 6.00 am right through to 3.00 am the next day,” said Ponsa.

The coastal location of the tunnel is very demanding for electrical equipment due to the high ambient temperatures that reach well over 30° C in the summer, combined with high humidity.  Even so, the drives and their ancillary systems has enabled Windoor to limit outages to just one day a year when it shuts for essential maintenance.

The facility was built by Czech-based wind tunnel specialists Strojirna Litvinov and opened in 2012. The tunnel chamber is four meters in diameter and 15 meters high. It can accommodate up to eight skydivers at a time. The four ACS800 VSDs – one per fan -- are linked by a SCADA system that enables them to be controlled by a “driver”, who uses a joystick to adjust the wind speed to meet the exact requirement of the flyers inside the tunnel.

As well as providing beginners with an introduction to the sport of skydiving, 15 minutes in the chamber is the equivalent experience as 15 freefall jumps from an aircraft making it an ideal training facility for more experienced skydivers. But the wind tunnel has helped indoor skydiving become a sport in its own right for a new generation of ‘Proflyers’. It has become so popular that it has given rise to the  Wind Games, which in 2018 saw more than 200 Proflyers competing in speed races, freestyle and formation flying, with over half a million people watching online. In July 2017, Windoor Realfly was where two flyers set a new Guinness World Record for uninterrupted indoor freefalling --a flight of seven hours and 15 minutes.

The upward flow of air that enables flyers to effectively freefall in the tunnel is provided by four massive electric fans. When indoor tunnels were first built the wind speed was regulated by adjusting the pitch of the fan blades. This approach wastes energy and fails to provide precise control. Modern facilities now rely on VSDs.

Safety and efficiency depend on the response of the drives. The motor needs to hit the set speed as fast as possible – typically that might mean going up from 65 percent being used by one flyer to 72 percent needed by the next flyer. This fast response is vital for safety - it ensures that the flyer has the ideal wind speed for their routine as well as enabling the fans to be shut-off quickly if they get into difficulties. But it is also vital for Windoor’s business as customers pay by the minute for their time in the tunnel.

To give an idea of the daily challenge facing the VSDs, the peak electrical load on the wind tunnel is around 1.4 megawatt (MW). Most of this is due to the amount of air that has to be shifted by the fan motors – over 1,000 cubic meters a second at top speed, that’s enough to fill a typical hot air balloon completely every two seconds.

When the facility first opened it was powered by diesel generators as the local utility could not meet the demand. There is now a direct electrical connection that has improved Windoor’s carbon footprint and energy efficiency.

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