Thermal Performance of a Heat Storage Module Using PCM’s With Different Melting Temperature: Experimental

1990 ◽  
Vol 112 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Mohammed M. Farid ◽  
Yongsik Kim ◽  
Atsushi Kansawa
Keyword(s):  
Heat Transfer ◽  
Melting Temperature ◽  
Latent Heat ◽  
Heat Storage ◽  
Flow Direction ◽  
Storage Period ◽  
Experimental Measurements ◽  
Latent Heat Storage ◽  
Maximum Increase ◽  
Theoretical Predictions

A latent heat storage module was constructed, consisting of 45 cylindrical capsules fixed vertically in 15 rows. The capsules, made of 0.335-m long copper tubes having external diameters of 31.8 mm, were fixed in an insulated rectangular duct. Three commercial waxes having melting temperatures of 44°C, 53°C, and 64°C were selected. Each of the three sets of 15 tubes was filled with different wax. For comparison purposes, experiments were also done with a single commercial wax, having a melting temperature of 53°C, in all the tubes. During heat charge, hot air flowed across the capsules such that the melting temperature of the waxes decreased in the flow direction. Air flow direction was reversed during heat discharge. Experimental measurements showed some improvement in the heat transfer rates during both heat charge and discharge when three types of PCM’s were used. There was no improvement in the heat transfer rate during the sensible heat storage period, while a maximum increase of 15 percent was observed during the latent heat period. Theoretical predictions for the performance of the storage module were in reasonable agreement with the experimental measurements.

scholarly journals Effective Separation of a Water in Oil Emulsion from a Direct Contact Latent Heat Storage System

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2264 ◽  
Author(s):  
Sebastian Ammann ◽  
Andreas Ammann ◽  
Rebecca Ravotti ◽  
Ludger Fischer ◽  
Anastasia Stamatiou ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Latent Heat ◽  
Direct Contact ◽  
Heat Storage ◽  
Storage System ◽  
Heat Transfer Fluid ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
Oil Emulsion ◽  
Water In Oil Emulsion

The problem of emulsification between Phase Change Material (PCM) and Heat Transfer Fluid (HTF) in direct contact latent heat storage systems has been reported in various studies. This issue causes the PCM to flow out of the storage tank and crystallize at unwanted locations and thus presents a major limitation for the proper operation of such systems. These anomalies become more pronounced when high HTF flow rates are employed with the aim to achieve fast heat transfer rates. The goal of this paper is to find a method which will enable the fast separation of the formed emulsion and thus the uninterrupted operation of the storage unit. In this study, three separation methods were examined and the use of superhydrophobic filters was chosen as the best candidate for the demulsification of the PCM and HTF mixtures. The filter was produced by processing of a melamine sponge with different superhydrophobic adhesives and was tested with emulsions closely resembling the ones formed in a real direct contact setup. The superhydrophobic filter obtained, was able to separate the emulsions effectively while presenting a very high permeability (up to 1,194,980 kg h−1 m−2 bar−1). This is the first time the use of a superhydrophobic sponge has been investigated in the context of demulsification in direct contact latent heat storage.

Thermal Conductivity Enhancement in a Latent Heat Storage Device

2013 ◽  
Vol 860-863 ◽  
pp. 590-593
Author(s):  
Cha Xiu Guo ◽  
Ding Bao Wang ◽  
Gao Lin Hu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Solid State ◽  
Liquid Phase ◽  
Phase Change ◽  
Latent Heat ◽  
Heat Storage ◽  
Storage Device ◽  
Latent Heat Storage ◽  
Conductivity Enhancement

High conductivity porosity materials are proposed to enhance the phase change materials (PCM) in order to solve the problem of low conductivity of PCM in the latent heat storage device (LHSD), and two-dimensional numerical simulation is conducted to predict the performance of the PCM by CFD software. During the phase change process, the PCM is heated from the solid state to the liquid phase in the process of melting and from the liquid phase to the solid state in the solidification process. The results show that porosity materials can improve heat transfer rate effectively, but the effect of heat transfer of Al foam is superior to that of graphite foam although the heat storage capacity is almost the same for both. The heat transfer is enhanced and the solidification time of PCM is decreased since the effective thermal conductivity of composite PCM is increased.

Thermal Properties Analysis of Several N-Alkanes Eutectic Mixtures Applied in Building Envelopes

2012 ◽  
Vol 512-515 ◽  
pp. 3007-3010
Author(s):  
Jing Yu Huang ◽  
Shi Lei Lv ◽  
Chen Xi Zhang ◽  
Zhi Wei Wang
Keyword(s):  
Thermal Properties ◽  
Melting Temperature ◽  
Latent Heat ◽  
Heat Storage ◽  
Eutectic Mixture ◽  
Scanning Calorimetry ◽  
Latent Heat Storage ◽  
Building Envelopes ◽  
Eutectic Mixtures ◽  
Change Material

This study focuses on the preparation, thermal properties of alkanes eutectic mixtures (n-Octadecane/n-Eicosane, n-Octadecane/n-Docosane and n-Heptadecane /n-Eicosane) as candidate phase change material (PCM) for low temperature latent heat storage systems in building envelopes. Their melting temperature and latent heat were tested by Differential scanning calorimetry (DSC). The testing values were closed to calculation values of accepted theory that ensured the reliability of those datas. The results indicated n-Octadecane/n-Docosane eutectic mixture was more promising PCM for buildings in terms of melting temperature (25.3°C) and latent heat values of melting (158.2J/g).

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