cars by night

Cabin cool down

To identify the temperatures in different zones of the passenger cabin the workflow to setup the KULI system is shown.

In a transient simulation the influence of the HVAC system in a cool down simulation in summer or heat up simulation in winter is performed.


Determination of component influences to temperatures  in the head and foot area of the driver and passengers (1st and 2nd row) based on A/C circuit performance and different air flow situations within the passenger compartment (fresh air, recirculated air, defrost or idle conditions).

Workflow for a typical cool down simulation

1st set up of an engine cooling circuit

2nd extend model with an A/C circuit

3rd add adjusted passenger compartment

4th Show temperature distribution inside the passenger compartment


The influence of the HVAC as a mixture of heating up (by PTC, heater core or heat pump) and cool down can be simulated. Different state of the art refrigerants (e.g. 1234yf, CO2) can be used and the influence of oil in the circuit can be considered. The whole vehicle cooling system (coolant circuits and AC circuits) in combination with the passenger compartment is using one GUI. The accuracy of the simulation can be increased by using additional CFD results for different outlet positions of the HVAC box. Different inlets into the compartment (e.g. defrost, nozzles for the driver or passengers in the 2nd row) can be considered. Influences of an additional battery thermal management on the passenger comfort can be investigated.

Optimization potential of used components can be figured out with the help of tables, 2D charts, diagram of the temperature distribution inside the passenger compartment and necessary parameters can be adjusted automatically. 

Related KULI modules


see online library (search for "advanced cabin" or "cool down")