While over-door air curtains are a very familiar feature on buildings in temperate Central Europe, they remain an absolute exception for buses. Where buses are concerned, over-door air curtains, also known as air showers, are almost exclusively used in hot or tropical climates. The Franconian transport operator infra fürth verkehr gmbh has just had seven Mercedes-Benz Citaro Low Entry (LE) models fitted with the cutting-edge technology. The vehicles were handed over to Klaus Dieregsweiler of infra forth verkehr gmbh by Rüdiger Kappel, Head of Sales, Mercedes-Benz Buses and Coaches, on 22 December.
Over-door air curtain technology was originally developed for use in warm countries. Special fan units are fitted above the doors to direct the air vertically downwards at high speed. This creates an air curtain which acts as a “climate separator”, preventing an exchange of heat between the interior and exterior air. This works both on hot days when cold, air-conditioned air is prevented from escaping through the open doors and on cold days when warm air is prevented from escaping. In more temperate climates door air curtains are just as useful as they are in tropical countries – or perhaps even more so, as they bring with them two additional safety-relevant advantages. In the winter months, the air blown downwards is warm, which means that the floor area around the doors dries more quickly, enhancing passive safety in snowy and icy conditions. The system has an additional benefit. In practically any external temperature, the warm air prevents condensation from forming on the glass surfaces of the doors. Minimizing misting of the windows is a significant safety factor, particularly at door 1 where all-round visibility is enhanced.
Source: Daimler AG