Drives control energy consumption at LEGOLAND

Something within the region of 1800 litres of water per second are pumped round the channels so that children and adults can have fun at LEGOLAND. This requires energy and energy consumption is now higher on the agenda than ever before. This is why regulating the water flow in the attraction is of supreme importance. The goal here is to use only the necessary amount of water to send the guests on a wild ride in the tub-shaped boats. A band hauls these up onto a higher level. Here we find 125 kW propeller pumps which send the water out in a long vessel with curves, fish ladders and small bumps, all of which create the rafting effect.

"By installing Danfoss VLT 6172 132 kW frequency converters on the two pumps of the ride we have reduced energy consumption. At the same time it is now easier to regulate the water volume because the frequency converter ensures that the pumps only circulate the necessary volumes of water", says Anders Christensen who works as an electrical technician at LEGOLAND. Previously we used wood shutters and gates to regulate water volume. We would then send the surplus water back to its starting point. The pumps operated at the same speed irrespective of how much water was required. Installation of the frequency converters means that it is possible to close all shutters so there is no longer any waterfall. At the same time it is possible to control and regulate the water volume as required at any given moment. "We can also send the boats off much faster, and the more we can send off in one hour, the more we reduce the waiting time for our guests", says Anders Christensen.

Safety is always uppermost in our minds, and here energy optimisation has also brought with it excellent results. "We did have a problem with boats banging against the timbers when they departed and returned because we could not control the flow of water. We have now solved this problem by adjusting the frequency converters on the two pumps to 43.0 and 46.0 HZ respectively - so now there is a bit of difference between them. This makes the ride more pleasant for the children" says Anders Christensen. As a technician he is really pleased that frequency converters mean less wear and tear on mechanical parts, which means the attractions last longer.

LEGOLAND has worked with Danfoss for many years. "We chose the frequency converters from Danfoss because we know that we can depend on them. They are also quite straightforward for technicians to handle. Once you have learnt to program them, the rest is easy, so it is an advantage to have the same type available throughout the park. Complete familiarity with Danfoss frequency converters means that when on a rare occasion a frequency converter does go down, we can get it up and running again in no time. It is very important from the point of view of the guests at LEGOLAND that no attraction is out of service more than is absolutely necessary. Here the frequency converters have been such a great asset", says Anders Christensen.

Improved energy efficiency of River Rafting and other activities such as the installation of light-emitting diodes has meant that LEGOLAND's green accounts continue to look better. This famous amusement park is on its way to becoming a truly climate-friendly organisation.