Seat material impacts EV driving range, scientists say

October 14, 2014 // By Christoph Hammerschmidt
Key to range improvements for electric vehicles is an intelligent energy management. A smart energy management scheme needs to take into account the impact of energy guzzlers like air conditioning and interior heating systems. A research project now examines the impact of car seats on energy efficiency. Sounds weird? Not at all: heating and cooling are swallowing significant amounts of energy.

After thrust, components dedicated to control the temperature inside the car (air con and heating) rank second when it comes to electric energy consumption in EVs. Both, air conditioning and heating are loading down the battery and thus reduce the driving range if they are used. In a research project, the Hohenstein Institute collaborates with research institutes FILK (Freiberg, Saxony) and IHD (Dresden, Saxony) now determines how thermally optimised seat could affect the energy consumption. The project aims at devising theoretical models of the heat transport in seat cushions, developing a model of heat transport processes and the practical implementation of thermally optimised seat systems.

The researchers focus on the use of appropriate materials and combine them intelligently to provide a certain amount of passive climate control. No development goal are active solutions such as heating and cooling for the seats. During the first phase of the project, the scientists are determining the effect of the human body and the thermal energy it emits to complex upholstery materials. Towards this end, the group is studying different seat covers using standard and functional textile materials. In addition, several usage scenarios are taken into account. A constant factor in this complex interplay is the optimal temperature for humans which lies about 23°C with textile surfaces. By means of several measurement systems, the researchers derive quantitative load factors describing the material or material combination as well as its heat conducting properties under dry and humid conditions.

These reference values are serving as the basis for the process simulation during heat transport. The simulations are carried out by means of the Finite Element Method (FEM), which typically is used to calculate complex components in engineering and vehicle building. In this case, the method is used to represent contradictory physical influences and their effects. The simulation enables the scientists to determine which material combinations have a positive impact on both heating and cooling behaviour. The