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 ◽  
...  

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.

1993 ◽  
Vol 115 (4) ◽  
pp. 240-243 ◽  
Author(s):  
Ch. Charach

This communication extends the thermodynamic analysis of latent heat storage in a shell-and-tube heat exchanger, developed recently, to the complete heat storage-removal cycle. Conditions for the cyclic operation of this system are formulated within the quasi-steady approximation for the axisymmetric two-dimensional conduction-controlled phase change. Explicit expressions for the overall number of entropy generation units that account for heat transfer and pressure drop irreversibilities are derived. Optimization of this figure of merit with respect to the freezing point of the phase-change material and with respect to the number of heat transfer units is analyzed. When the frictional irreversibilities of the heat removal stage are negligible, the results of these studies are in agreement with those developed recently by De Lucia and Bejan (1991) for a one-dimensional latent heat storage system.


2020 ◽  
Vol 148 ◽  
pp. 987-1001 ◽  
Author(s):  
Pouyan Talebizadeh Sardari ◽  
Donald Giddings ◽  
David Grant ◽  
Mark Gillott ◽  
Gavin S. Walker

Author(s):  
Ben Xu ◽  
Peiwen Li ◽  
Cholik Chan

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.


2013 ◽  
Vol 58 (1-2) ◽  
pp. 108-113 ◽  
Author(s):  
Takahiro Nomura ◽  
Masakatsu Tsubota ◽  
Akihito Sagara ◽  
Noriyuki Okinaka ◽  
Tomohiro Akiyama

Author(s):  
T. Ravi Kumar

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.


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