Abstract. This paper presents a 5-zone-car-cabin model which is able to simulate the car cabin's thermal condition depending on several influencing parameters. This includes the solar radiation, to which special attention is paid in this paper. In addition, a generic methodology for parameter optimization considering measurements on a reference vehicle is presented. Thus, a very high degree of determination of the model was achieved. This paper is motivated by the impact of auxiliary loads on overall energy consumption in battery electric vehicles. The further use of the model is intended to calculate the energy saving potentials of the heating, ventilation, and air conditioning system by reducing or increasing the target interior temperature. This is necessary for a predictive control of secondary consumers. IntroductionMost of the potential car buyers do not trust in the vehicle range of battery electric vehicles (BEVs), as they are often smaller than the manufacturer indicates. In addition, the so-called range anxiety (The fear that a vehicle cannot reach its destination because of insufficient range.) is still widespread. In order to counteract the range disadvantage, an efficient use of the available energy is necessary. This requires the knowledge of the overall energy requirement to cover the present route. Each route has different energy loads in terms of propulsion and secondary consumers. The heating, ventilation, and air-conditioning (HVAC) system can be the largest auxiliary load. It is shown that the range of electric vehicles significantly reduces when the HVAC system is activated [1], [2]. Depending on the weather conditions, up to 25% of the required energy is used by secondary consumers [3]. Thus, the HVAC system offers a considerable energy saving potential by reducing or increasing the target interior temperature in case of a predictive control. However, possible energy savings quickly lead to the conflict with passenger's comfort. To identify the energy saving potentials of an HVAC system, some preparation steps are necessary, according to figure 1.