This study confirmed paraffin wax as a phase change material (PCM) that enhances the latent heat energy storage performance. Computational fluid dynamics (CFD) software was used with an experimental investigation to evaluate three vertical shell and tube heat exchanger configurations: conventional shell and tube heat exchangers (STHX), needle fin heat exchangers (SFTHX), and novel spiral fin heat exchangers (SSTHX).
Water at 20°C was fed through the tube to initiate the solidification of the PCM. The results of the CFD models showed a significant performance of SSWTHX compared to other models. This model showed the complete solidification process in 3193 seconds, while SFTHX showed 4317 seconds and STHX showed 5710 seconds. These results show a significant improvement in the thermal energy storage efficiency of the PCM by 44% and 25% for the STHX and STHX models compared to the SSWTHX model. Under the 3000 s solidification process, 98% of the paraffin wax in the SSWTHX model was solidified compared to 90% in the SFTHX. The increase in the SSWTHX surface area and the presence of spiral wire in the heat exchanger led to improved performance. The CFD temperature distribution showed a strong agreement with the experimental work, which confirmed the three CFD models. These results support the configuration of the SSWTHX with a higher efficiency solar thermal storage system.
