A Novel DoE based Front-End Airflow Target Setting Approach for Optimum HVAC Cool Down Performance

The front-end air flow conditions have a substantial impact on the cool down performance of a vehicle Heating, Ventilation and Air-Conditioning (HVAC) system. The performance of a mobile HVAC system is analyzed by conducting tests on the vehicle in a drive cell, subjecting it to different drive cycles. This now can be done virtually using system level simulation or one-dimensional (1D) tools. Target values for condenser air inlet velocity and temperature for these HVAC performance focused drive cycles needs to be established during the development phase to meet the cool down functional objectives of the vehicle. Thus, in the early stages of development, 1D tools play a major role. Condenser air flow should be sufficient and the temperature should be as low as possible at different vehicle operating conditions to have good air-conditioning (AC) performance. This paper focuses on a Design of Experiments (DoE) approach to investigate the effect of condenser air inlet conditions on overall AC performance and introduces an effective target setting strategy to help move towards an optimal front-end module design. First, a Central Composite DoE (CCD) study is conducted to show how condenser air inlet conditions: air inlet velocity and temperature at different vehicle speeds affect the cool down functional objectives. Second, after identifying the most contributing factors, a novel target setting strategy is proposed to accurately identify the required condenser air inlet velocity and temperature conditions for optimum AC performance. This new strategy can guide the engineers to design more efficient front-end cooling modules to meet all the requirements of AC system and passenger comfort. The simulations and DoE are both done using Siemens’ LMS Imagine. Lab AMESim 15.