Mahdi Momeni, Saman Jalilian, Amir Fartaj
Abstract: Due to the mismatch between energy supply and demand in thermal systems, this paper introduces a novel phase change material (PCM) heat exchanger based on two working fluids to provide thermal energy storage for the airside. The PCM is integrated into a compact single-slabbed crossflow heat exchanger based on air and liquid flow. A three-dimensional computational fluid dynamics (CFD) simulation is employed to perform a numerical analysis of fluid flow and heat transfer in the model. The dynamic thermal performance of the system is presented for both the PCM charging and discharging processes. The PCM stores excess thermal energy in the charging process, which is then released to the airside during periods of demand when the system's hot working fluid is unavailable. Results have been presented based on fluid temperatures, PCM average solid fraction, PCM phase transition procedure, and heat transfer rates during the charge and discharge processes. It has been observed that, in the discharge process, the stored thermal energy provides the airside with a heating load of 117.9 kJ, which leads to approximately 150 seconds of heating time. Moreover, heat transfer analysis shows that between the air outlet temperature of 28°C and 18°C, latent heat transfer dominates over the sensible heat transfer, causing most of the delay in air outlet temperature drop to occur in this region. Furthermore, it is concluded that using PCM in the heat exchanger can provide extra thermal energy of 100.7 kJ during the discharging process with the share of latent heat of 48% in the PCM heat transfer process. The findings attained in this study will shed light on the development of PCM heat exchangers and guide future research in designing more effective and efficient PCM heat exchangers, leading to enhanced overall system performance.
Keywords: PCM Heat Exchanger, Thermal Energy Storage, Thermal Management; Air and Liquid Flow, Phase Change Material.
Date Published: October 2, 2023 DOI: 10.11159/jffhmt.2023.012
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