Abstract
Keywords:
Warm-up performance, HVAC, Fluent, INKA/TILL, Thermal comfort
Abstract
In the development of vehicle heating or cooling performance the most important factors to date have been how fast the air temperature of the passenger compartment can be raised. For this, either an excessive air from the fan or an over-design of the HVAC system to supply lots of energy into the passenger compartment in a short time is needed. Problems caused by this, for example are: increased consumer dissatisfaction due to the noise of the HVAC system under the dashboard, the problem of package layout in the engine room by the HVAC (Heating, Ventilation and Air Conditioning) system size and a great loss of energy by ventilation exhausted from the passenger compartment. They can hinder development of new cars. Many new cars are now equipped with an auxiliary heater to gain enough heating capacity especially in the case of HEV or the most recent highly efficient diesel engined vehicles. This research is based on the simulation of heat and mass flows around the car interior. It shows that the warm up performance can be more accurately predicted by considering the amount of heat loss through the roof, glazing and doors by coupling of airflow and heat transfer. For this, the commercial CFD code Fluent [7] and the 1D heat transfer program INKA/TILL [8] was used. Passenger thermal comfort was also studied using a numerical dummy model, the latter feature has not been considered as a part of the warming up test routine.