A generic simulation of energy consumption of automobile air conditioning systems

The air conditioning system in a car is, in addition to the heating system, installed to increase the comfort in the passenger compartment. Comfort is not the only reason for automotive air conditioning systems, as road safety also improves with the comfort of the driver, as a pleasant environment reduces driver fatigue. The rising environmental problems and, hence, resulting stringent legislation are forcing the automobile industry to develop cars with ever decreasing fuel consumptions. The question of better fuel consumption and energy utilisation does not stop with the engine and aerodynamics, but is required of the air-conditioning system as well. Thus, incessantly innovative technologies are developed to decrease the energy required by the air-conditioning systems. The interaction of the refrigerant cycle components and the rapidly changing operating conditions of the car (speed, revolutions per minute, etc.) places extensive demands on the control system. In addition, the air-conditioning system is also designed for high ambient temperatures (cool down), but is mostly used in fairly moderate conditions. This operation allows for energy saving control strategies such as externally controlled compressors, blower motor control, etc. The experimental comparison of different air-conditioning systems, components or control strategies is very time consuming and extensive, and the use of an air-conditioned wind tunnel is inevitable when experiments need to be done with reproducible ambient conditions.This, combined with the high costs of installation and operation of a wind tunnel is a major problem. Furthermore, the effect of component or control strategy enhancements should be available as soon as possible in the early stages of design. The above considerations have prompted the rapid development of new powerful simulation tools, but in most cases the simulation tools are focused on one specific component or problem only. A more holistic approach would be to combine the calculations of two or more programs. This implies the adaptation of the model to more programs which leads to a lack of transparency. Obviously, the entire development work cannot be done entirely by simulation, especially in the later phases of the development where it would still be necessary to build prototypes to evaluate the done work experimentally. However, in the early stages of development, it would be advantagous to work without expensive prototypes.