Cabin Thermal Needs: Modeling and Assumption Analysis

Abstract

Interest for cabin thermal needs has strongly increased for the past 10 years, particularly due to heating. Indeed, the development of electric and hybrid vehicles stressed the need to rethink the cabin thermal design and the HVAC, this high-consuming auxiliary, which can dramatically decrease the vehicle electric range. Thus, this paper presents a detailed transient and mono-zonal model of a car cabin in order to predict the thermal needs. The model is developed using the MODELICA language via the DYMOLA environment. It considers conduction, convection, radiation heat transfers as well as the HVAC and water vapor impacts. The different assumptions of the model are discussed and important considerations usually not discussed are highlighted. The thermal loads are also analyzed. Finally, the heating and cooling thermal needs are computed for steady state mode and for convergence mode as well as for varying recirculation ratios. This work is useful to better understand the whys and wherefores related to the cabin thermal needs.

Modeling and control of heat pump system for battery electric buses

“…On the inner level, the model considers the heat transfer through convection and radiation between the wall inner side and the cabin interior. 30…”

“…The wall model includes a convection sub-model that calculates the convection coefficients, further elaborated in Brèque and Nemer. 30 Also, the internal mass exchanges heat with the cabin through convection and radiation. The model considers the passenger thermal losses and the passenger water vapor generation.…”

Dynamic Thermal Model of Passenger Aircraft for the Estimation of the Cabin Cooling and Heating Requirements

“…In particular, the design of the control logic was performed with Matlab, while Modelica was used to create a simplified thermal model of the pressurized aircraft compartments and to test the proposed control strategies. Further examples of one-dimensional thermal models developed for automotive applications are documented in [7,8]. An alternative approach to model the heat and mass transfer mechanisms occurring within the pressurized spaces of a commercial airliner is documented in [9].…”