Computerized Simulation of Automotive Air-Conditioning System: Development of Mathematical Model and Its Validation
A semi-empirical model for simulating thermal and energy performance of an automotive air-conditioning (AAC) system in passenger vehicles has been developed. The model consists of two sections, namely empirical evaporator correlations and dynamic load simulation. The correlations used consider sensible and latent heat transfer performance of the evaporator coil. The correlations were obtained from the experimental data of actual air conditioning system for a compact size passenger car. The sensible heat transfer correlation relates the evaporator air off dry-bulb temperature to inlet air dry-bulb temperature, humidity ratio, evaporator air velocity, condenser inlet air dry-bulb temperature, condenser air velocity and compressor speed. The latent heat transfer correlation relates the coil air-off humidity ratio to the same six independent variables. The dynamic load simulation model was developed based on the z-transfer function method with a one-minute time step. The cooling load calculations were performed using heat gain weighting factors. Heat extraction rate and cabin air dry-bulb temperature calculations were carried out using air temperature weighting factors. The empirical evaporator sensible and latent heat transfer correlations were embedded in the loads calculation program to enable the determination of evaporator inlet and outlet air conditions, the cabin air temperature and relative humidity. Comparisons with road test data indicated that the program was capable of predicting the performance of the automotive air-conditioning system with reasonable accuracy.
Keywords: Automotive air conditioning (AAC), passenger cabin, thermal load model.
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ABOUT THE AUTHORS
Haslinda Mohamed Kamar
Haslinda Mohamed Kamar, is a member of ASHRAE. She received her Bachelor’s Degree in Mechanical Engineering from University of Glasgow, Scotland in 1993, Master and PhD in Mechanical Engineering from University Teknologi Malaysia in 1997 and 2009, respectively. She is now a senior lecturer in the Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Her areas of interest are automotive air-conditioning system, thermal comfort & energy efficiency in hot climates, indoor air quality (IAQ), natural ventilation as passive cooling strategy in buildings and computational fluid dynamics (CFD) modeling and simulation.
Mohd Yusoff Senawi
Mohd Yusoff Senawi, graduated with Bachelor of Mechanical Engineering from The University of New South Wales in 1987. Received Post Graduate Diploma in Computer Science, Master and PhD in Mechanical Engineering from Universiti Teknologi Malaysia (UTM) in 1989, 1993 and 2000, respectively. Currently a Senior Lecturer at UTM. Research interests include cooling loads calculation and energy analysis of air conditioning systems.
Nazri Kamsah
Nazri Kamsah is a member of ASHRAE. He received his Bachelor’s Degree in Mechanical Engineering from University of Sunderland, United Kingdom in 1983, Masters of Engineering (Mechanical) from Universiti Teknologi Malaysia in 1988, and PhD in Mechanical Engineering from University of New Hampshire, Durham, USA in 2001. He is currently a senior lecturer in the Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. His areas of interest include computational solid mechanics, finite element modeling and simulation, thermal management in microelectronics, thermal comfort and energy efficiency in buildings, natural ventilation as passive cooling strategy for buildings, indoor air quality (IAQ) and computational fluid dynamics (CFD) modeling and simulation.
Haslinda Mohamed Kamar
Haslinda Mohamed Kamar, is a member of ASHRAE. She received her Bachelor’s Degree in Mechanical Engineering from University of Glasgow, Scotland in 1993, Master and PhD in Mechanical Engineering from University Teknologi Malaysia in 1997 and 2009, respectively. She is now a senior lecturer in the Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Her areas of interest are automotive air-conditioning system, thermal comfort & energy efficiency in hot climates, indoor air quality (IAQ), natural ventilation as passive cooling strategy in buildings and computational fluid dynamics (CFD) modeling and simulation.
Mohd Yusoff Senawi
Mohd Yusoff Senawi, graduated with Bachelor of Mechanical Engineering from The University of New South Wales in 1987. Received Post Graduate Diploma in Computer Science, Master and PhD in Mechanical Engineering from Universiti Teknologi Malaysia (UTM) in 1989, 1993 and 2000, respectively. Currently a Senior Lecturer at UTM. Research interests include cooling loads calculation and energy analysis of air conditioning systems.
Nazri Kamsah
Nazri Kamsah is a member of ASHRAE. He received his Bachelor’s Degree in Mechanical Engineering from University of Sunderland, United Kingdom in 1983, Masters of Engineering (Mechanical) from Universiti Teknologi Malaysia in 1988, and PhD in Mechanical Engineering from University of New Hampshire, Durham, USA in 2001. He is currently a senior lecturer in the Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. His areas of interest include computational solid mechanics, finite element modeling and simulation, thermal management in microelectronics, thermal comfort and energy efficiency in buildings, natural ventilation as passive cooling strategy for buildings, indoor air quality (IAQ) and computational fluid dynamics (CFD) modeling and simulation.
