Heat Pump Air Conditioning Systems for Optimized Energy Demand of Electric Vehicles

Abstract

The air conditioning system of a passenger car causes significant power consumption. For hybrid and electric vehicles the power consumption for heating of the cabin and windshield (defrosting, defogging) at low ambient temperatures in particular plays an important role, considering that there is only little or no waste heat available. Electric heating of the cabin air drastically reduces the driving range. Additionally, in case of electric vehicles there may be a demand for cooling of the traction battery at high ambient temperatures while in contrary the waste heat of the power electronics could be used for cabin heating at low ambient temperatures if its temperature level is raised by means of a heat pump. This chapter illustrates strategies for the transition of a conventional heating, ventilation and air conditioning (HVAC) system for fuel based vehicles to a more appropriate one for highly electrified vehicles from the standpoint of an effective reduction of energy consumption. The benefits of implementing heat pump technology into the traditional air conditioning system are shown in contrast to systems utilizing electric air heating and a proposition of a vehicles’ thermal management system is given, integrating the air conditioning system into an overall vehicle cooling and heating system for an even further reduction of energy consumption. The chapter is complemented with a comparison of two HVAC system topologies regarding their overall annual energy demand for air conditioning and highlighting the implication of heat pump technology from this point of view.