Perfect air conditioning in every climate zone The luxury liner belonging to Royal Caribbean International is 350 meters long and 41 meters wide. It can accommodate 4,180 passengers seeking an exclusive vacation experience. They expect the air in all interior spaces to be at just the right temperature, no matter what climate zone the ship happens to be in. Each cabin has its own air conditioning, with which passengers can set the temperature they prefer. Many of the ship’s rooms are in the interior or have windows that cannot be opened. Air exchange in most parts of the ship takes place only in the ventilation system. Nearly 3,000 fans installed Limited space is a big challenge for shipboard air conditioning, so the ventilation equipment has to take up as little space as possible – one of the reasons why powerful ebm-papst EC centrifugal blowers with forward-curved blades are installed in the cabin air conditioners. RadiPac series EC centrifugal fans with backward-curved blades are installed in the public areas. All told, 2,956 fans ensure a pleasant climate on-board. Active PFC reduces harmonics When so many EC fans are connected in parallel to a single generator and a single power network, so-called harmonics can arise: EC fans receive pulsed input current, so with a sinusoidal AC supply, phase-shifted rather than sinusoidal input currents result. To counter this, ebm-papst has added an active harmonic filter to the fan’s electronics: active PFC (power factor correction). With active PFC installed, a power factor of nearly one is reached, satisfying the requirements of the EN 61000-3-2 standard without the need for additional measures. Active PFC technology allows the design of a smaller generator from the beginning, since a lower peak load can be assumed. That saves money, weight and space.