Integrated Development and Validation of HVAC Modules Using a Combined Simulation and Testing Approach

Cost saving and short turn-around time are two major challenges for the development of automotive HVAC modules and systems. Traditionally, the development process is test-driven with a typical workflow shown on the left-hand side of Figure 1:

Utilizing experimentally validated Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) methodologies, engineers are able to predict the aerodynamic and thermal behavior of the HVAC module and ductwork as well as the structural design robustness prior to physical testing in the laboratory. In addition to providing comparable results to those achieved through testing (e.g. temperature regulation curves and airflow distribution) the CFD results provide unique insight into the complicated airflow and thermal mixing behavior inside the HVAC module and ductwork. The early integration of CFD into the design process allows many more design concepts to be evaluated than would be possible through testing alone. The use of validated CFD/FEA methods improves the agreement with test results, allowing an integrated approach in which the benefits of 3D simulation and testing can both be realized. Such a development and validation process significantly shortens design time, reduces the number of prototype units, and lowers costs of laboratory tests because the first physical prototype already features high development levels. In the design validation (DV) and product validation (PV) phase, CFD and FEA are also heavily involved to provide guidance for design modification and optimization [1]. The flow chart illustrating the integrated HVAC module development workflow is shown on the right-hand of figure-1.

The present paper describes the details of the integrated development and validation process for HVAC product development. Techniques and methodologies used in the process are discussed. Specific examples from recent HVAC module development projects are cited to illustrate the integrated validation approach.