Underground railway environment in the UK Part 3: Methods of delivering cooling

Ventilating an underground railway environment in which there is to be heavy traffic of electrically propelled rapid transit trains differ from those normally encountered in air-conditioning work. The heat generated by the train motors and electric lighting, together with body heat from passengers, is so great that excessive temperatures would prevail in summer unless a volume of air in excess of that required for breathing is supplied. The installation of in car air-conditioning units adds another major heat release source in the tunnel. This heat must be ejected to make using in car air-conditioning units worthwhile. This part of the paper investigates potential methods of delivering cooling to underground railways environment. The suitability of each cooling method is assessed with the help of a purposely developed mathematical model, which has been discussed at length in part two of the paper, to investigate the heat load in a generic underground railways environment. For each cooling method, the model predicts the tunnel and train carriage temperatures and relative humidities together with the PPD. (C) 2003 Elsevier Ltd. All rights reserved.