Optimierung des Heiz- und Klimakonzepts zur Reduktion der Wärme- und Kälteleistung im Fahrzeug (English shop)

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At very low temperatures, battery electric vehicles suffer a considerable reduction in range due to the heating and air conditioning of the cabin. This work presents an approach to easing the trade-off between range and thermal comfort. To this end, design criteria for the Heating, Ventilation and Air Conditioning system (HVAC system) of motor vehicles are developed using statistical weather and vehicle movement data.

Heating and cooling systems for vehicles and options for reducing heat transfer into and out of the passenger compartment are presented. The power and energy demand is determined on the basis of the design criteria developed and with the aid of a passenger compartment simulation model. The focus of the work is on reducing the amount of energy required at constant comfort compared with the production status. In this context, the heat flows of the individual heat transport mechanisms, supply air, exhaust air, heat and water vapour emission of the occupants as well as the heating and cooling of the thermal masses are determined in order to derive from them the improvement measures with the greatest benefit.

Building on this, concepts for optimising the HVAC system and the vehicle cabin are developed for a vehicle of the A and C segments, and the reduction in power and energy demand is determined. The measures heat pump, direct heating and cooling, thermal insulation, recirculation mode, preconditioning and reduced thermal masses result in energy savings of between 70 and 80% compared with a standard vehicle with an electric resistance heater.