Smart heating panels to increase thermal comfort and efficiency

Abstract

BACKGROUND: The increasing electrification poses new challenges with respect to thermal comfort in vehicle passenger cabins. While conventional air heating with electric heaters is technically possible, it causes significant reductions in the electric driving range. OBJECTIVE: Two contradicting objectives are to be achieved: Fast heat up to provide thermal comfort and high energy efficiency to maximize the driving range under all conditions. METHODS: This apparent area of conflict can be eased by the usage of low temperature radiation reducing the energy intensive heat up of the cabin air. In order to provide high energy efficiency, the emitted radiation should mostly be directed towards relevant body regions of the passengers, resulting in the necessity to redesign the passenger cabin. RESULTS: A novel approach to redesign and optimize the dashboard and a resulting radiation heating system are presented. In order to reduce computational effort of such an optimization, the complex three-dimensional geometry is sliced into simplified two-dimensional regions which are considered individually. The resulting heating system has been manufactured and integrated into a class A vehicle. Objective thermal comfort measurements as well as subjective comfort ratings have been conducted to validate the simulative approach and the resulting energy savings of approximately 30 %. CONCLUSIONS: The developed approach to achieve a fast time to comfort as well as an increased energy efficiency shows promising results as the heating system based on it cuts performs well considering objective and subjective measurements.

A larger statistical basis and a wider application area of the PMV equation in the Fanger model: application area of the PMV equation

“…The human model in combination with the PMV and Predicted Percentage of Dissatisfied (PPD) equations (Fanger 1972;NEN-EN-ISO-7730 2005), derived by him, are used in the world on a daily basis. In practice, but also in scientific research (Mohamed and Korb 2002;Mohamed and Korb 2003;Feriadi and Wong 2004;Backes, Trenktrog, and Eckstein 2019;Zang and Lin 2021) it regularly appears that the PMV equation is applied outside the range on the basis of which the PMV equation is derived. In practice, this can occur, for example, in the evaluation of the measurement or calculation of temperature exceedances in a room, for sedentary activities (Gao, Wang, and Wargocki 2015;Baglivo et al 2017).…”