Abstract
With increasing electrification of the powertrain, the efficient use of energy for air-conditioning of car cabins is essential. Despite a reduction of energy demand, providing thermal comfort for the passengers is very important. Commonly air based conditioning systems are used to heat up and cool down the compartment as well as to renew the air to prevent unpleasant odors and limit the humidity. The quality of these properties is not only affected by the HVAC system but also by the car cabin itself and the way of supplying air into it. The ventilation efficiency and the age of air are quantities to evaluate the quality of a ventilation system in terms of pollutant removal and renewal of air. These characteristic values can be measure with the use of tracer gas methods.
A flexible measurement system for the use in car cabins was developed at the E.ON Energy Research Center. It consists of 20 small sensors for the tracer gas CO2, which are powered by batteries and communicate wireless. The calculation of the air change efficiency and local age of air is done by a post processing application included in the data processing software. The system has been tested in a standard sedan cabin. The system provides a robust comparability and accuracy. The characteristic values of the air flow in the compartment can be used to optimize the distribution of volume flow rates at the different air ducts. Furthermore the position of the diffusers plays a key role for an efficient air change in the cabin.
KEYWORDS – CO2, Air Quality, Ventilation, Air Change Effectiveness, Measurement