Numerical Thermal Performance Analysis of a Phase Change Material-Air-Liquid Heat Exchanger Using Latent Heat Thermal Energy Storage
Date of Award
Mechanical, Automotive, and Materials Engineering
Computational fluid dynamics, Heat exchanger, Phase change material, Thermal energy storage, Thermal management
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Due to the mismatches in energy supply and demand in thermal systems, employing latent heat thermal energy storage using phase change materials (PCMs) is a reliable and effective solution. Compact heat exchangers are an essential component of thermal management systems in several industries, such as the HVAC industry, automotive, and many others. In this regard, this paper introduces a novel PCM-air-liquid heat exchanger to increase thermal system performance by providing a hybrid heat source to the airside. A novel numerical work based on multiphysics coupling of heat transfer and double fluid flow and phase change within a complex geometry is represented. Numerical heat transfer analysis is performed on the model based on three-dimensional computational fluid dynamics (CFD) simulation. In order to make a thorough thermal performance assessment, the dynamic behavior of the system is investigated for the heat exchanger in two studies of air heating and cooling mode and conducted for the PCM charging and discharging processes. Furthermore, the effect of airside flow variation on the thermal response of the system is studied, and the results are discussed based on the fluids temperature, heat transfer rate, and the PCM phase transition procedure. It is demonstrated from the results attained that the PCM can store excess thermal energy from the working fluid during the charging process and releases it to the airside during the discharging process. It is observed that the heating load of 323 kJ for the air-heating study and cooling load of 188 kJ for the air-cooling study is stored during the PCM charging process. This thermal energy provides up to 6 and 9 minutes of extra airside heating and cooling time during the PCM discharging process for the studies, respectively. The share of PCM latent component of the airside heat transfer is determined to be at an average of 51% between all simulation cases. It is also observed that by increasing the airflow rate, the discharged heating/cooling load is decreased slightly, and the heating/cooling time is reduced notably. The presented thermal energy storage system offers a unique solution for the start-stop function implemented in many hybrid and electric vehicles. During short periods of engine shutdown, the system could provide passenger thermal comfort and enable effective energy savings.
Momeni, Mahdi, "Numerical Thermal Performance Analysis of a Phase Change Material-Air-Liquid Heat Exchanger Using Latent Heat Thermal Energy Storage" (2023). Electronic Theses and Dissertations. 8936.