scholarly journals Experimental Research of the Heat Storage Performance of a Magnesium Nitrate Hexahydrate-Based Phase Change Material for Building Heating

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7108
Author(s):  
Yang Li ◽  
Caixia Wang ◽  
Jun Zong ◽  
Jien Ma ◽  
Youtong Fang
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Storage ◽  
Thermal Storage ◽  
Magnesium Nitrate ◽  
Storage Device ◽  
Outer Side ◽  
Nitrate Hexahydrate ◽  
Magnesium Nitrate Hexahydrate ◽  
Change Material

Phase change heat storage material is a preferred material in solar building heating or off-peak electric-heat storage heating technology and is the research focus. A compact phase change thermal storage device has been designed and experimentally studied for improving heating system load in this work. A new type, magnesium nitrate hexahydrate-based phase change material has been studied to improve the cooling degree and crystallization difficulty. The focus of this study is on the heat charging and discharging characteristics of this new phase change material. The heat storage device has two groups of coils, the inner side which carries water and the outer side which is the phase change material. A testing system was built up to value the thermal cycling performance of the heat storage device. The measurement data include phase change material temperature field, water inlet and water outlet mean temperature, heat charging and heat discharging depth, and flow rates over the operating period. The results show the phase change material has a quick response with the operating temperature range of 20–99 °C. Its latent heat is 151.3 J/g at 91.8 °C. The heat storage density of this phase change material is about 420 MJ/m3. The thermal performance degradation is about 1.8% after 800 operation cycles. The phase change thermal storage device shows flexibility and a great potential to improve the capacity and economy of heating systems.

Volume Sizing for Thermal Storage With Phase Change Material for Concentrated Solar Power Plant

2014 ◽  
Author(s):  
Ben Xu ◽  
Peiwen Li ◽  
Cholik Chan
Keyword(s):  
Power Plant ◽  
Phase Change ◽  
Phase Change Material ◽  
Storage Tank ◽  
Solar Power ◽  
Heat Storage ◽  
Storage System ◽  
Thermal Storage ◽  
Concentrated Solar Power ◽  
Change Material

With a large capacity thermal storage system using phase change material (PCM), Concentrated Solar Power (CSP) is a promising technology for high efficiency of solar energy utilization. In a thermal storage system, a dual-media thermal storage tank is typically adopted in industry for the purpose of reducing the use of the heat transfer fluid (HTF). While the dual-media sensible heat storage system has been well studied, a dual-media latent heat storage system (LHSS) still needs more attention and study; particularly, the sizing of volumes of storage tanks considering actual operation conditions is of significance. In this paper, a strategy for LHSS volume sizing is proposed, which is based on computations using an enthalpy-based 1D model. One example of 60MW solar thermal power plant with 35% thermal efficiency is presented. In the study, potassium hydroxide (KOH) is adopted as PCM and Therminol VP-1 is used as HTF. The operational temperatures of the storage system are 390°C and 310°C, respectively for the high and low temperatures. The system is assumed to operate for 100 days with 6 hours charge and 6 hours discharge every day. From the study, the needed height of the thermal storage tank is calculated from using the strategy of tank sizing. The method for tank volume sizing is of significance to engineering application.

scholarly journals Analysis of Heat Transfer and Natural Convective of a Phase Change Material

2021 ◽  
Vol 9 (VII) ◽  
pp. 3028-3037
Author(s):  
T. Ravi Kumar
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Heat Storage ◽  
Storage Device ◽  
Latent Heat Storage ◽  
Recovery System ◽  
Solid Liquid ◽  
Change Material

A phase-change material (PCM) is a substance with a high latent heat storage capacity which on melting and solidifying at a certain temperature, is capable of storing and releasing large amounts of energy. Various PCM like Paraffin wax, stearic acid are considered which are used to absorb heat from the coolant water from the engine. The conduction and convection criterion of heat transfer enable the PCM to store this heat as latent heat. The amount of convection and temperature change brought about due to the heat flux has been simulated and studied in detail using FLUENT. The thermal energy storage device (TESD) works on the effect of absorption and rejection of heat during the solid-liquid phase change of heat storage material. The overall function of the TESS is dominated by the PCM. The PCM material should be selected considering the application and the working conditions. Depending on the applications, the PCMs should first be selected based on their melting temperature for heat recovery system.

scholarly journals Dynamic numerical study on phase change thermal storage heat transfer

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4171-4179
Author(s):  
Jie Cui ◽  
Guofeng Wang ◽  
Zhitang Guo ◽  
Shuo Yang ◽  
Honggang Pan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Storage ◽  
Thermal Storage ◽  
Transfer Effect ◽  
Fin Spacing ◽  
Change Material

Targeted at the poor heat transfer effect of the phase change thermal storage heat exchanger due to the low thermal conductivity of the phase change material, a fin-tube type phase change thermal storage heat exchanger has been proposed in the study. A 2-D model of the phase-change heat storage unit was established, and the dynamic heat transfer law of the melting and solidification of the phase change material, and the influence of the fin structure size on the heat storage/release performance of the heat exchanger were numerically analyzed. The results show that in the area close to the tube wall, the smaller the fin spacing, the larger the thickness, the faster the phase change heat storage/release speed, and the better heat transfer effect. In the central area of the phase change material, the greater the fin spacing and thickness, and the better the heat transfer effect of the phase change heat storage/release. The area close to the outer wall has the smallest temperature change, and the heat storage/release effect is the worst. Therefore, the use of energy storage heat exchangers with gradual fin thickness and spacing is an effective method to improve the heat transfer efficiency of existing equipment. In addition, in order to improve the heat exchange effect of the edge area of the phase change, its structure could be changed or the heat exchange form can be increased.

Numerical Investigation of the Melting of a Phase Change Material in a Thermal Storage Device With Embedded Air Flow Channels

2016 ◽  
Author(s):  
Mustafa Koz ◽  
Hamza S. Erden ◽  
H. Ezzat Khalifa
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Air Flow ◽  
Melting Process ◽  
Thermal Storage ◽  
Time Dependent ◽  
Storage Device ◽  
Aluminum Tubes ◽  
Change Material

Two time-dependent mathematical and numerical models with different levels of complexity and fidelity were developed to investigate the melting of a phase change material (PCM) configured as a number of aluminum-encased, PCM-filled slabs with embedded micro-channel aluminum tubes, and with parallel air-flow passages interposed between the slabs. Melting was first analyzed with the COMSOL Multiphysics® finite-element model (FEM) in a 2-D domain representing a full-size slab. The melting process is simulated via the apparent heat capacity method. The model captures the effect of natural convection in the PCM melt as well as the conjugate heat transfer through the aluminum tubes. A fast-executing quasi 2-D reduced-order model (ROM) was developed for repetitive design optimization studies. The ROM relies on a time-dependent 1-D closed-form solution of the heat conduction equation in a melting PCM, coupled with variations of the air temperature and heat transfer coefficient. Consequently, the FEM results were employed to develop corrections to the ROM. The corrected ROM was then utilized to study the melting process in a multi-slab thermal storage device that is designed to freeze the PCM at night and release 500 W-h of cooling over a span of ∼10 h during the day.

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