Sorption-based air conditioning for battery-driven electric busses


Engelpracht, Mirko © Copyright: Lehrstuhl fuer Technische Thermodynamik der RWTH Aachen


Mirko Engelpracht

Group Leader Sorption Systems Engineering


+49 241 80 98176



Strong regulations regarding noise and air pollution in urban areas promote the electrification of public transport. For battery-driven electric vehicles (BEV), air conditioning is still an unsolved problem. Since the waste heat of a combustion engine is not available, the passenger compartment has to be heated by other means on cold days (winter case). On hot days (summer case), cooling and dehumidification have to be provided by an air-conditioning unit driven by the battery. Using a standard compressor-based heat pump, the electrical power consumption for heating and air conditioning can be as high as for traction. Thus, the range of BEV is severely decreased.

As a possible solution to this dilemma, we propose a sorption-based air-conditioning unit. This unit can provide heating, cooling, and dehumidification while being locally emission-free. At the same time, the sorption-based unit only needs a fraction of electrical power compared to a compressor-based air-conditioning system. Multi-scale approach involving four institutes at RWTH Aachen University:

  Multi-scale approach involving four institutes at RWTH Aachen University Copyright: © LTT

Four institutes of RWTH Aachen University, covering all scales from the nanometer to kilometer, develop the proposed sorption-based air-conditioning unit: The ITMC develops tailored sorption materials, which the LTT is using for the design of the sorption-based air-conditioning unit. The ISEA takes care of the integration of the air-conditioning unit into the bus and the charging of the system, while the ISB analyzes the effects of charging times on the bus schedule and the public-transport grid.


Project Details

Project Duration

July 1, 2013 to July 1, 2015


Funded by the Excellence Initiative of the German federal and state governments.
Exploratory Research Space – ERS