This study manifests the improvement in the charging and discharging time of the encapsulated PCM arranged in packed bed thermal energy storage. The combined effect of the aspect ratio (ratio of height to diameter of the packed bed) and cascaded configurations of phase change materials (PCMs) integrated with the solar water heating system is analyzed numerically. The mathematical model is validated by the experimental study available in the literature. Initially, an optimal aspect ratio of the packed bed is predicted for charging/discharging. And then, PCMs are arranged in different layers in the packed bed based on the optimal aspect ratio to analyze the combined effect of PCM configurations and optimal aspect ratio. The charging and discharging time were decreased with an increasing aspect ratio to 2.5. Afterward, an increased aspect ratio showed a trivial change in the charging and discharging time of latent heat thermal energy storage (LHTES). Furthermore, at an optimal aspect ratio of 2.5, PCMs were arranged in the packed bed with both axial (parallel) and combined axial‐radial layers (parallel and series) to see the impact of the cascaded configuration. Charging and discharging time of combined axial‐radial layers configuration was respectively found to be 17.21% and 18.5%, less than charging time without layers.
In this study, a novel configuration of the latent heat thermal energy storage module based on the packed bed of encapsulated phase change material is investigated. The module is modeled and simulated using a Multiphysics tool COMSOL. The simulation results are validated with the experimental data. Using the validated model, initially, water was used as heat transfer fluid, and then refrigerant R‐134 and R‐22 were also used as heat transfer fluid (HTF) to predict the impact on the charging time. The comparison in terms of their thermo‐physical properties is also carried out. The results indicated that by using refrigerants (R‐134 and R‐22) as HTF, decreased the charging time. When the water was used as HTF, it took 11 hours to completely charge the system. Whereas, the charging time for R‐134 and R‐22 was 8.75 and 8.4 hours, respectively. It was also observed that edges of packed bed were melting much slower than the remaining bed. Therefore, to increase the transfer of heat near the edges, geometry of the module is modified and their impact is investigated.
This study focuses on the heat transfer intensification of concentric tube type thermal energy storage (TES). The collective influence of aspect ratio (ratio of length to diameter of the tube) and number of fins is investigated. To optimize thermal energy storage, first an optimal aspect ratio investigated. And then, optimal number of fins is obtained. Results are compared based on the amount of liquid fraction available after 120 minutes of charging and discharging. It was found that with an increasing aspect ratio, liquid fraction also increased, but up to the aspect ratio of 11. Afterwards, an increased aspect ratio showed insignificant change in the liquid fraction. Similarly, liquid fraction in case of charging was increased with increasing the number of fins up to 8. Afterward, an increased number of fins showed insignificant change in the liquid fraction.
This research focuses on the enhancement of the heat transfer in the concentric tube type of thermal energy storage (TES). The collective influence of the aspect ratio and number of fins is investigated. First, an optimal aspect ratio of the concentric tube TES is found. Additionally, then, the optimal number of fins is found. This combined optimal configuration of TES is then compared with concentric tube TES without. Liquid fraction of the combined optimal configuration was increased by 100% for case of charging as compared to TES without fins.
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