Improving heat transfer in triplex tube heat exchanger containing phase-change materials by modifications of length and position of fins

In many heat transfer related applications, there is a need for a stable, constant supply temperature. As a result, the integration of intermittent renewable sources of heat into these processes can prove to be challenging, requiring special temperature smoothing devices or strategies. This study focuses on the application of phase change materials integrated into a double tube heat exchanger as a possible thermal smoothing device. The objective of this study is to evaluate the ability of the exchanger to smoothen out temperature variations within the cold stream outlet while the hot stream is subject to oscillating inlet conditions. A computational fluid dynamics approach is used where a numerical model is developed, validated and then used to model the conjugate heat transfer within the heat exchanger. Four organic phase change materials (PCM) with different phase change temperatures were selected for investigation (myristic, octadecane, eicosane, and wax) to study the relationship between melting temperature and stabilization performance. A parametric study was then conducted by varying the Reynolds number of the flow as well as temperature oscillation period and amplitude to study the sensitivity of the system. The results confirm the potential of a phase change material-based thermal capacitor at dampening oscillations across the heat exchanger.

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Designs of PCM based heat exchangers constructions for thermal energy storage tanks – examples and case study for selected design

E3S Web of Conferences ◽

10.1051/e3sconf/20187001010 ◽

2018 ◽

Vol 70 ◽

pp. 01010

Author(s):

Marta Kuta ◽

Dominika Matuszewska ◽

Tadeusz Michał Wójcik

Keyword(s):

Energy Storage ◽

Heat Exchanger ◽

Phase Change ◽

Phase Change Material ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Phase Change Materials ◽

New Technologies ◽

Tube Heat Exchanger ◽

Change Material

Increasing energy consumption in residential and public buildings requires development of new technologies for thermal energy production and storage. One of possibilities for the second listed need is the use of phase change materials (PCMs). This work is focused on solutions in this area and consists of two parts. First one is focused on different designs of thermal energy storage (TES) tanks based on the phase change materials. The second part is the analysis of tests results for TES tank containing shelf and tube heat exchanger and filled with phase change material. Thermal energy storage tank is analyzed in order to use it in domestic heating and hot utility water installations. The aim of this research was to check the applicability of phase change material for mentioned purpose. Results show that using phase change materials for thermal energy storage can increase amount of stored heat. The use of properly selected PCM and heat exchanger enables the process of thermal energy storing and releasing to become more efficient.

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Thermal performance enhancement of energy storage systems via phase change materials utilising an innovative webbed tube heat exchanger

Energy Procedia ◽

10.1016/j.egypro.2018.09.027 ◽

2018 ◽

Vol 151 ◽

pp. 57-61

Author(s):

Ahmed H.N. Al-Mudhafar ◽

Andrzej F. Nowakowski ◽

Franck C.G.A. Nicolleau

Keyword(s):

Energy Storage ◽

Heat Exchanger ◽

Phase Change ◽

Thermal Performance ◽

Phase Change Materials ◽

Performance Enhancement ◽

Storage Systems ◽

Energy Storage Systems ◽

Tube Heat Exchanger

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Second-Law Efficiency of an Energy Storage-Removal Cycle in a Phase-Change Material Shell-and-Tube Heat Exchanger

Journal of Solar Energy Engineering ◽

10.1115/1.2930057 ◽

1993 ◽

Vol 115 (4) ◽

pp. 240-243 ◽

Cited By ~ 12

Author(s):

Ch. Charach

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Phase Change ◽

Phase Change Material ◽

Latent Heat ◽

Heat Storage ◽

Latent Heat Storage ◽

Tube Heat Exchanger ◽

Shell And Tube ◽

Change Material

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.

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Study of heat transfer and pressure drop characteristics of air heat exchanger using PCM for free cooling applications

Thermal Science ◽

10.2298/tsci130531096k ◽

2016 ◽

Vol 20 (5) ◽

pp. 1543-1554 ◽

Cited By ~ 1

Author(s):

Sivakumar Kalaiselvam ◽

Kanchipuram Sureshkumar ◽

Vijeykishoor Sriram

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Pressure Drop ◽

Phase Change Materials ◽

Thermal Characteristics ◽

Ambient Air ◽

Dynamics Modeling ◽

Tube Heat Exchanger ◽

High Heat Transfer ◽

Free Cooling

Free cooling is the process of storing the cool energy available in the night ambient air and using it during the day. The heat exchanger used in this work is a modular type which is similar to the shell and tube heat exchanger. The shell side is filled with Phase Change Materials (PCM) and air flow is through the tubes in the module. The modules of the heat exchanger are arranged one over other with air spacers in between each module. The air space provided in between the module in-creases the retention time of the air for better heat transfer. Transient Computational Fluid Dynamics modeling is carried out for single air passage in a modular heat exchanger. It shows that the PCM phase transition time in the module in which different shape of fins is adopted. The module with rectangular fins has 17.2 % reduction in solidification compared with the plain module. Then steady state numerical analysis is accomplished to the whole module having the fin of high heat transfer, so that pressure drop, flow and thermal characteristics across the module and the air spacers are deter-mined for various air inlet velocities of 0.4 to 1.6 m/s. To validate the computational results, experiments are carried out and the agreement was found to be good.

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