scholarly journals On-Board Cold Thermal Energy Storage System for Hydrogen Fueling Process

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 561 ◽  
Author(s):  
Young Kim ◽  
Dong Shin ◽  
Chang Kim
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Storage System ◽  
Energy Storage System ◽  
Hydrogen Gas ◽  
Safety Issues ◽  
Energy Efficiency Improvement ◽  
Fueling Station

The hydrogen storage pressure in fuel cell vehicles has been increased from 35 MPa to 70 MPa in order to accommodate longer driving range. On the downside, such pressure increase results in significant temperature rise inside the hydrogen tank during fast filling at a fueling station, which may pose safety issues. Installation of a chiller often mitigates this concern because it cools the hydrogen gas before its deposition into the tank. To address both the energy efficiency improvement and safety concerns, this paper proposed an on-board cold thermal energy storage (CTES) system, cooled by expanded hydrogen. During the driving cycle, the proposed system uses an expander, instead of a pressure regulator, to generate additional power and cold hydrogen gas. Moreover, CTES is equipped with phase change materials (PCM) to recover the cold energy of the expanded hydrogen gas, which is later used in the next filling to cool the high-pressure hydrogen gas from the fueling station.

scholarly journals Enhanced Thermal Characteristics of NG Based Acetamide Composites

2019 ◽  
Vol 8 (10) ◽  
pp. 4227-4231 ◽  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Storage System ◽  
Thermal Characteristics ◽  
Energy Storage System ◽  
Melting Time

Fatty acids are a distinguished category of phase change materials (PCM). However, their inferior thermal conductivity value restricts their potential for thermal energy storage system. Carbonaceous nanomaterials have emerged as promising thermal conductivity enhancer materials for organic PCMs. The present study focuses on preparing a novel PCM nanocomposite comprising of small amount of nanographite (NG) in molten acetamide, an organic PCM, for elevation of the thermal characteristics and examining the trend of the nanocomposite through the course of charging / discharging process. These PCM-nanocomposites are prepared by dispersing NG in molten acetamide with weight fractions of 0.1, 0.2, 0.3, 0.4 and 0.5 %. The scanning electronic microscopic (SEM) analysis was conducted for the characterization of PCM nanocomposite. The energy storage behaviour of the prepared nanocomposites were analyzed with the help of differential scanning calorimeter instruments, which showed that there is no observable variation in the melting point of the nanocomposite, and a decline in the latent heat values. Furthermore, thermal conductivity trend of the nanocomposites caused by NG addition was investigated, which indicated enhancement of thermal conductivity with increasing NG concentration. Further, nanocomposites with a 0.4 wt. % of NG, displayed appreciable increase in rate of heat transfer, reducing melting time and solidification time by 48 and 47 %, respectively. The prepared PCM nanocomposites displayed superior heat transfer trend, permitting substantial thermal energy storage.

scholarly journals A Numerıcal Investıgatıon of The Thermal Behavıor of Dıfferent Phase Change Materıals In Thermal Energy Storage Systems

2021 ◽  
Author(s):  
Mehmet Kan
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Thermal Behavior ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Storage System ◽  
Energy Storage System ◽  
Thermal Energy Storage System ◽  
Thermal Energy Storage Systems

Abstract Phase change materials (PCM) are widely used in thermal energy storage systems due to their high heat storage properties. However, due to the low thermal conductivity of PCMs, different surface areas are employed in order to increase the amount of energy. One of these methods is to use fins with high thermal conductivity. This study numerically investigated the thermal behavior of different PCMs (paraffin, paraffin wax, polyethylene glycol 6000) during the melting process in a thermal energy storage system with 15 fins. A FOX 50 heat flow meter was used for thermal conductivity measurements of these PCMs, and TA DSC Q200 (Differential Scanning Calorimetry) devices were used for specific heat measurements. The thermal property data of these measured PCMs were used in a time-dependent analysis. With the PCM data obtained, time-dependent thermal analyses were carried out using the Ansys-Fluent program based on the Computational Fluid Dynamics (CFD) method. The effect of these different PCMs on the melting processes was investigated by using water at 75oC in a 15-fin thermal storage system by observing their thermal behavior in the thermal energy storage system. In addition, cost analyses were conducted by determining the required amount of PCMs for the thermal storage system.

scholarly journals The Effects of Fin Parameters on the Solidification of PCMs in a Fin-Enhanced Thermal Energy Storage System

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 198 ◽  
Author(s):  
Mohammad Javad Zarei ◽  
Hassan Bazai ◽  
Mohsen Sharifpur ◽  
Omid Mahian ◽  
Bahman Shabani
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Performance Enhancement ◽  
Negative Impact ◽  
Storage System ◽  
Metallic Copper ◽  
Energy Storage System ◽  
Optimal Point

In the present study, a triplex-tube, employing fin-enhanced phase change materials (PCMs), as a thermal energy storage (TES) system was studied numerically. The main flaw of the PCMs is their low thermal conductivity that restricts their effectiveness for energy storage applications. Metallic (copper) fins are added to the geometry of the system to improve their function by extending the heat transfer area. The effects of the presence, configuration, and dimensions of copper fins were investigated to understand the best design for minimizing the solidification time and achieving the best performance enhancement for the TES system selected for this study. The results revealed that the best performance belonged to fins with a mix configuration, with an attachment angle of 90° and the length and width of 28 mm and 1 mm, respectively. Using this configuration could reduce the required time for complete solidification by around 42% compared to the system without fins. Moreover, it was concluded that increasing the length of the fin could offer its positive effect for enhancing the performance of TES system up to an optimal point only while increasing the width showed a diverse influence. Furthermore, the angles between the tube surface and the fin direction were investigated and 90° was found to be the best choice for the TES case selected in this study. In addition, placement of the fins on the surface of internal or external tube or mix method did not show a significant effect while placing the fins on the external surface of the tube showed even a negative impact on the performance of the TES system compared with when no fins were applied.

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