Heat capacity and heat transfer coefficient estimation for a dynamic thermal model of rail vehicles

This paper provides a method for estimating the parameters of a dynamic thermal rail vehicle model and reference values of these parameters. A linear dynamic discrete time system is used to model the thermal behaviour of the vehicle relevant for thermal comfort and air conditioning. The heat capacities and the heat transfer coefficients are stated for various vehicle classes. While dynamic thermal models are state of the art in buildings, cars and rail vehicles, no reference values can be found for these parameters. This paper shows how to estimate the heat capacity and the heat transfer coefficient from measured data for a given thermal model structure. Two different measurement data sources are used: special experiments and existing measurements. While specially designed experiments are only possible for new measurements, it is shown that satisfying results can be obtained with existing measurements. Measurement data from 13 vehicles are used to provide reference values for all passenger vehicles classes: tram, metro, regional and main-line. If all assumptions are satisfied, simulation results of the indoor air temperature agree well with measurements. Reference values for parameters of a dynamic thermal model are the basis for a wide application of such models in the rail vehicle industry.