Simulation of transient thermal comfort in trains

Abstract

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The present investigation deals with the challenges in all vehicle industries with respect to air conditioning taking into account transient effects. Transient phenomena occur mainly during door opening and closing, pre-cooling, pre-heating. Numerous vehicles have difficulties to meet the thermal comfort criteria which are imposed by the customer. Typically, requirements are given for the minimum and maximum air velocity, the temperature level, the maximum gradient in different sections and the fresh air rate. More sophisticated requirements includes the predicted mean vote (PMV) and predicted percentage dissatisfied (PPD). Tools which are capable to predict the impact of relevant design options have been used in steady state for several years already. The possibility to use these tools for transient processes in an industrial framework will be discussed.