Optimization of an Outdoor AC Unit Piping System Using Finite Element Method and Regression Model for Vibration Analysis

Wong, Yong Wen (2025) Optimization of an Outdoor AC Unit Piping System Using Finite Element Method and Regression Model for Vibration Analysis. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

This study aims to optimize the piping system of an outdoor air conditioning (AC) unit with respect to the structure’s vibration characteristics, such as dynamic behaviour, by employing advanced analytical techniques, specifically the Finite Element Method (FEM) and Regression Method. The study has developed a comprehensive finite element model that simulates the dynamic behaviour of the AC unit from 0 to 100 Hz, obtaining five mode shapes. A thorough comparison between simulated results and experimental data was performed and the obtained average percentage of error was 10.2%. After the validation on the accuracy of the model, Design of Experiment (DOE) techniques were used, predominantly the Latin Hypercube Sampling Design and the impact of various design parameters, including different pipe lengths and wall thicknesses on the dynamic behaviour of the piping system was analysed using a sensitivity bar model. Response surfaces and regression models were developed to correlate the input parameters with the natural frequency, facilitating the optimization of the design for enhanced performance. The accuracy of predicted natural frequencies from other DOE methods, including Optimal Space Filling Design and Box-Behnken Design, which are available in ANSYS Design Exploration, is also compared using verification points. The method used in this study has the ability to mitigate vibration-related issues, improve the operational reliability of outdoor AC units, and contribute to the development of more efficient and durable HVAC systems. Through this study, valuable insights are provided into the dynamic behaviour of piping systems, paving the way for future advancements in engineering design and analysis.