scholarly journals An investigation of the melting process of RT-35 filled circular thermal energy storage system

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 574-580 ◽  
Author(s):  
Soroush Ebadi ◽  
Manar Al-Jethelah ◽  
Syeda Humaira Tasnim ◽  
Shohel Mahmud
Keyword(s):  
Energy Storage ◽  
Numerical Model ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Greenhouse Gas Emission ◽  
Melting Process ◽  
Temperature Regulator ◽  
Melting Fraction ◽  
Solid Liquid

Abstract One of the main solutions to the issue of global warming and greenhouse gas emission caused by burning fossil fuels is storing energy in an efficient way. In this work, the detailed melting process of RT-35 as a phase change material (PCM) inside a cylindrical latent heat thermal energy storage (TES) system is investigated both numerically and experimentally. To achieve this aim, an experimental setup comprising of a transparent vertical cylindrical enclosure as a latent heat TES system, a constant temperature bath, and a temperature regulator is built. Moreover, a numerical model using COMSOL multiphysics is developed to simulate the melting process and provide a more detailed information on the flow and thermal fields. The model is able to provide the temperature and velocity fields, heat transfer behaviour, melting fraction, and the trend of solid-liquid interface at different time intervals. To validate the numerical model, a comparison between melting fraction and solid-liquid interfaces of the numerical model and experimental work is conducted which shows a good agreement between experimental and numerical results.

A General Model for Analyzing the Thermal Performance of the Heat Charging and Discharging Processes of Latent Heat Thermal Energy Storage Systems*

2001 ◽  
Vol 123 (3) ◽  
pp. 232-236 ◽  
Author(s):  
Yinping Zhang ◽  
Yan Su ◽  
Yingxin Zhu ◽  
Xianxu Hu
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Performance ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
General Model ◽  
Phase Change Materials ◽  
Melting Process ◽  
Specific System

During melting of phase change materials (PCM) encapsulated in a container, the solid PCM sinks to the bottom or floats to the top of the container according to the gravitational force and buoyancy resulting from the difference between solid and liquid densities. Compared with the solidification process, the melting process has a quite different behavior. Although the heat transfer characteristics of melting processes in various typical kinds of containers have been studied, the general model for analyzing the thermal performance of both melting and solidification processes of latent heat thermal energy storage (LHTES) systems composed of PCM capsules has not been presented in the literature. The present paper describes such a model which can be used to analyze the instantaneous temperature distribution, instantaneous heat transfer rate, and thermal storage capacity of a LHTES system. For solidification, the model is validated with the results in the literature. The thermal performance during melting of a LHTES system composed of PCM spheres is analyzed as an example. The model is not limited to a specific system or a specific PCM, so it can be used to select and optimize system design and to simulate the thermal behavior of various typical LHTES systems.

Latent Heat Thermal Energy Storage Systems with Solid-Liquid Phase Change Materials: A Review

2018 ◽  
Vol 20 (6) ◽  
pp. 1700753 ◽  
Author(s):  
Nan Zhang ◽  
Yanping Yuan ◽  
Xiaoling Cao ◽  
Yanxia Du ◽  
Zhaoli Zhang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Liquid Phase ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Storage Systems ◽  
Thermal Energy Storage Systems ◽  
Solid Liquid

Experimental and Numerical Study of a Latent Heat Thermal Energy Storage Unit Enhanced by Fins

2020 ◽  
Author(s):  
Addison Hockins ◽  
Samantha Moretti ◽  
Mahboobe Mahdavi ◽  
Saeed Tiari
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Numerical Model ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Experimental Testing ◽  
Storage Unit ◽  
Energy Storage Unit ◽  
Charging Time

Abstract Latent heat thermal energy storage (LHTES) systems are used to store thermal energy and release it for later use by melting or solidifying a phase change material (PCM). One problem associated with latent heat thermal energy storage systems is the low thermal conductivity of most commercially aviable phase change materials. This can have a significant negative effect on the thermal performance of the system by leading to a longer charging or discharging process. Several passive heat transfer enhancement techniques are used to resolve this issue. Common passive heat transfer enhancement techniques include inserting fins and extended surfaces into the PCM, embedding heat pipes or other two-phase heat transfer devices within the PCM, dispersion of highly conductive nanoparticles in the PCM, and impregnation of highly conductive porous media with the PCM. The current study analyzes the effect of a fin-based enhancement technique on the thermal performance of a latent heat thermal energy storage unit. Copper fins are attached annually around the central pipe inside the PCM. A transient two-dimensional numerical model technique is developed using ANSYS FLUENT 19.0 to simulate the operation of the system. Baseline tests have been conducted experimentally for a system without fins to validate the numerical model. The results obtained from the numerical modeling are in good agreement with those of the experimental testing. Based on the experimental testing, the total charging time of the system using hot water at 70°C and flow rate of 7.57 L/min is around 47.9 hours which is very close to the prediction by the numerical model which is 48 hours. Numerical modeling of the system with 10 fins and 20 fins found that the charging time was decreased by 68.9% and 73.7%, respectively. The discharging time was also decreased by 73.2% and 79.1%, respectively.

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