Contribution of the Air Conditioning System to Reduced Power Consumption in Cars

The car air conditioning system causes approximately 0.5 l/100 km excess fuel consumption on average. To meet future fuel consumption and emission regulations improvements in the AC system are called for.

To consistently assess improvements in air conditioning power consumption, specific driving and temperature profiles are defined.

It is shown that improvements can be achieved by:

• Better thermodynamic component and system design
• Refrigerant expansion device sized for efficiency rather than maximum performance
• System control strategies such as variable air recirculation

Measurement of a refrigerant circuit on a system test bench reveal that the energy requirement for A/C can by reduced by 15% to 30% compared to current state of the art AC system technologies.

Only part of the presented measures are based on electronic controls however only the combination of all will lead to a significant reduction.