Thermal comfort in innovative climate control and thermal comfort concepts aiming to optimize the range of electric vehicles
07/2011 to 06/2014
Fraunhofer Gesellschaft für angewandte Forschung e.V.
Due to the different energy-specific setup of electric vehicles – primarily the fact that there is no combustion engine that could provide useful energy or waste heat for the purpose of air conditioning – it is necessary to develop alternative vehicle air conditioning systems. Possible alternative climate systems are, for example, local climate systems that take effect close to the body, based on methods such as seat ventilation systems or surface-heating. In order to quantify the energy efficiency and the ergonomic acceptance of these alternative air conditioning systems, it is also necessary to assess the effectiveness in terms of the occupants’ sense of comfort; in addition to the total energy consumption. Currently, the automotive sector is using standard methods according to ISO 14505-2 to evaluate local sense of comfort.
The aim of joining the BMBF research project (which was initiated by the Fraunhofer Gesellschaft) as an associate partner was to develop a new comfort model that is able to capture the reactions of the human body to spatially non-uniform time-varying conditions. Special emphasis was placed on modeling the influence of the contact heat transmission through temperature-controlled surface areas, which are – at least so far – not adequately mapped by models. The newly developed “Bilanz-Komfortmodell” (BKM) is based on the promising approaches of Fanger (1970) and Zhang (2003), integrated into a consistent model approach (Schmidt et al. 2015). The new modeling approach, which uses local energy balances, was reproduced in the modeling language Modelica and integrated into a library.