Skip to main content
European Commission logo print header

Thermally OPerated Mobile Air Conditioning Systems

Final Report Summary - TOPMACS (Thermally OPerated Mobile Air Conditioning Systems)

The TOPMACS project was devoted to the development of mobile air conditioning systems with a reduced impact on the environment, both direct and indirect. In the frame of the project, four first generation prototype air conditioning systems based on sorption cooling and metal hydride powered by the engine waste heat, have been developed and bench tested.

The refrigerants used in the TOPMACS systems (water, hydrogen or ammonia) have no impact on the environment and they are compliant with the new EU regulation on GHG emissions. In addition, the systems are driven by waste heat and they need only a small electrical power amount to be driven, thus dramatically reducing the indirect impact with respect to state of the art mobile air conditioning systems. Coupled with a small fuel burner the developed technologies have also the potential for operating when the thermal engine is switch-off, providing for instance the vehicle cabin pre-cooling and pre-warming on the conventional powertrain vehicles and making the systems suitable to the new vehicles equipped with electrified powertrains.

Two demonstrator vehicles have been equipped with the novel air conditioning systems:
- a passenger car with a silicagel-water sorption cooling system
- a heavy truck with a zeolite-water sorption cooling system.

In addition an upgraded activated carbon-ammonia cooling system bench prototype and a metal hydride mechanical compression-based cooling system bench prototypes has been realised and tested on the bench.

The benefit for the environment has be quantified experimentally by means of tests in the climatic chamber roller bench and virtually by means of a simulation tool which has been developed in the frame of the project and which is able to simulate all the technologies.

A methodology to evaluate at the same time thermal comfort and the associated energy performance has been developed. The project has been carried out by a consortium constituted by a major OEM, a Tier1 supplier, an advance material supplier and five acknowledged excellence centres gathering skilled European scientists and engineers in this specific field.

Key results:
- The TOPMACS A/C systems were able to improve the state-of-the-art sorption systems cooling power density up to nine times.
- No GHG emission due to refrigerant.
- Small CO2 emission due to A/C operation.
- Low to zero fuel consumption due to A/C usage.
-No impact on vehicle handling (no mechanical compressor attached to the engine).
-Coupled with a small fuel burner can provide air conditioning while the thermal engine is shut off (provide the cabin preconditioning, compatible with electrified powertrains).