Date of Award
5-16-2024
Publication Type
Thesis
Degree Name
M.A.Sc.
Department
Mechanical, Automotive, and Materials Engineering
Keywords
CFD Modeling;Computational fluid dynamics;Heat exchanger;Phase change material;Thermal energy storage;Thermal management
Supervisor
Amir Fartaj
Abstract
In this research, innovative strategies are employed to enhance the airside heating performance of a five-slab cross-flow heat exchanger integrated with phase change material (PCM). The PCM-integrated heat exchanger (PCM-HEX) incorporates two fluid flows and is improved to operate effectively during intermittent working fluid flow periods. The system targeted for investigation has previously undergone examination by prior researchers in a study referred to as the "reference study." In the reference study, a single type of PCM was inefficiently utilized, resulting in a suboptimal performance for the system. Two studies have been conducted to achieve the objective. Study 1 investigates the influence of PCM distribution, fin density, and PCM type on the thermal performance of a single-slab PCM-HEX. Study 2 employs the findings of Study 1 and strategically employs multiple PCMs to enhance the thermal performance of the five-slab PCM-HEX. Computational fluid dynamics (CFD) simulations are employed to analyze the dynamic behavior of the PCM-HEXs. During the charging process, the PCMs store thermal energy from the hot working fluid, subsequently releasing it to the airside during the discharging process. In study 1, Three PCM distributions, 15 different fin densities, and three PCMs with distinct melting temperatures are considered. Results reveal that placing PCM layers on the top and bottom of the slab leads to enhanced thermal performance. Also, decreasing the PCM domain’s fin density extends the heating time at low set point temperatures (SPTs). In addition, using a PCM with a higher melting temperature enhances the heating time at high SPTs. In study 2, by implementing the key outcome of study 1, four PCM distribution cases are investigated. It is found that placing PCM layers on the top and bottom of all five slabs effectively enhances the air-to-PCM thermal interaction. The thermal performance of this case is then further enhanced by employing multiple PCMs. The multi-PCM model can provide up to 170% improvement in the airside heat transfer rate during the first 94 s and up to 85% extra thermal energy to the airside during the first 5 min of the discharging process compared to the reference study. Moreover, the PCM effectiveness is found to be consistently higher than that of the reference study. In automotive applications, the proposed system is capable of offering substantially higher thermal performance in maintaining thermal comfort in the passenger cabin during brief stop periods in any modern vehicle featuring a start-stop technology.
Recommended Citation
Jalilian, Saman, "Thermal Performance Enhancement of a Crossflow PCM-to air and liquid Heat Exchanger" (2024). Electronic Theses and Dissertations. 9432.
https://scholar.uwindsor.ca/etd/9432