Battery electric vehicles are equipped with Mobile Air Conditioning systems (MACs) to ensure a comfortable indoor temperature in every climate and ambient condition, as well as the optional conditioning of the traction battery. An assessment of the global electrical energy consumption of various MACs has been conducted. The basis of the assessment procedure is the climate data GREEN-MAC-LCCP 2007 and the improved LCCP2013. The percentage driving time during 6 AM and 24 PM is divided into six different temperature bins with the solar radiation and relative humidity for 211 cities distributed over Europe, North-, Central and South America, Asia, South West Pacific and Africa. The energy consumption of the MACs is determined by a thermal vehicle simulation. In this work, four different MACs are simulated and compared. The MACs that are investigated are two conventional refrigeration cycles with PTC, one with R-1234yf and the other with R-744 as refrigerant, as well as two heat pump systems, one with R-134a and the other with R-744. Taking into account the number of vehicle registrations and the average distance traveled per city, the average energy consumption per kilometer, the annual energy consumption per car and the necessary energy for a BEV fleet for heating and cooling is estimated at city, country, continent and world level. This study deals also with the optimization of mobile air conditioning systems based on the Evans-Perkins process. These systems are used for cooling the passenger compartment. Additionally, a reversible system can be used as heat pump system for providing passenger and battery heating. The required electrical energy for this process depends on the temperature difference in the system. The available heat sources are discussed as well as the control strategy and the optimization potentials. Finally, a generic control structure for refrigeration cycles with the refrigerants R-744 and R-1234yf is also presented. The structure depends on independent, gain-scheduled controllers which results in a very flexible control structure. The R-744 heat pump system is an example of a relatively complex mobile air conditioning and heating system.