Development of a New HVAC Flow System for the Next Generation Automated People Mover

IHI has succeeded in development of a new generation Automated People Mover (APM). One of the features of this APM is the composite car body which enables stylish exterior, spacious cabin and light weight. This feature demanded the development of a new Heating, Ventilating, and Air-Conditioning (HVAC) system, which does not have any devices on the roof of the car, to avoid heavy weight on the composite body and to keep the cabin ceiling high for passenger comfort. Consequently we adopted a new HVAC flow system in which the air is supplied upwards from the bottom of the side windows while all the mechanical devices are placed under the floor. However, when the prototype was first designed, it caused congested flow channel due to its location and we had to have ducts that were too small. It was unexpectedly difficult to keep the space for HVAC system like in an ordinary layout. So at first, the prototype vehicle did not have enough HVAC performance due to lack of air flow. Therefore we performed full review of the duct system. We made desk analysis, duct model test, experiment on the prototype, and CFD simulation, for the improvement of the new HVAC flow system. Finally, we have established an excellent system with the new layout which has been validated on the prototype vehicle. In this paper, we describe the process of developing a new HVAC system, based on the results of actual measurement as well as CFD simulation.