scholarly journals Role of Phase Change Materials Containing Carbonized Rice husks on the Roof-Surface and Indoor Temperatures for Cool Roof System Application

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3280
Author(s):  
Hong Gun Kim ◽  
Yong-Sun Kim ◽  
Lee Ku Kwac ◽  
Mira Park ◽  
Hye Kyoung Shin
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Paraffin Wax ◽  
Heat Absorption ◽  
Rice Husks ◽  
Indoor Temperature ◽  
Cool Roof ◽  
Plastic Composites

This study researches the effect of phase change materials (PCMs) containing carbonized rice husks (CRHs) in wood plastic composites (WPCs) as roof finishing materials on roof-surface and indoor temperatures. A cool roof miniature model was prepared, and measurements were taken using three fixed temperatures of 30 to 32 °C, 35 to 37 °C, and 40 to 42 °C. Sodium sulfate decahydrate (Na2SO4·10H2O) and paraffin wax were selected as the PCMs. CRHs were used as additives to improve the thermal conductivities of the PCMs. At lower fixed temperatures such as 30 to 32 °C and 35 to 37 °C, the rates of increase of the surface temperatures of roofs containing CRHs with Na2SO4·10H2O, and paraffin wax, were observed to gradually decrease compared to those of the roofs without PCMs. The indoor temperatures for the above-mentioned PCMs containing CRHs were maintained to be lower than those of the indoors without PCMs. Additionally, as the CRH content in the PCM increased, the rates of increase of the roof-surface and indoor temperatures decreased due to a faster roof heat absorption by PCMs through the improved thermal conductivity of CRHs. However, under higher artificial temperatures such as 40 to 42 °C, Na2SO4·10H2O with CRHs exhibited no effect due to being out of latent heat range of Na2SO4·H2O. For paraffin wax, as CRH content increased, their roof- surface and indoor temperatures decreased. Especially, the surface temperature of the roof containing paraffin contained 5 wt.% CRHs reduced by 11 °C, and its indoor temperature dropped to 26.4 °C. The thermal conductivity of PCM was enhanced by the addition of CRHs. A suitable PCM selection in each location can result in the reduction of the roof-surface and indoor temperatures.

Thermal Conductivity Characterization of Nano-Enhanced Paraffin Wax

2011 ◽  
Author(s):  
Peter J. Sakalaukus ◽  
Andrew Mosley ◽  
Basil I. Farah ◽  
Kuang-Ting Hsiao
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Materials ◽  
Carbon Nanofiber ◽  
Paraffin Wax ◽  
Conductivity Enhancement ◽  
Notable Increase ◽  
Paraffin Waxes

Paraffin waxes are commonly used phase change materials for energy storage. However, the low thermal conductivity of the paraffin wax can limit the energy charging and discharging rate. In this research, a new nano-enhanced paraffin wax with dispersed conductive nanoparticles is tested for the thermal conductivity enhancement. A notable increase in the thermal conductivity has been measured from the carbon nanofiber enhanced paraffin wax.

scholarly journals A Review on Shape-Stabilized Phase Change Materials for Latent Energy Storage in Buildings

2020 ◽  
Vol 12 (22) ◽  
pp. 9481
Author(s):  
Monika Gandhi ◽  
Ashok Kumar ◽  
Rajasekar Elangovan ◽  
Chandan Swaroop Meena ◽  
Kishor S. Kulkarni ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Liquid State ◽  
Energy Demand ◽  
Phase Change Materials ◽  
Temperature Fluctuations ◽  
Good Evidence ◽  
Thermal Mass ◽  
Indoor Temperature

Many countries in the Global South have hot and dry climates with large diurnal temperature variations, which leads to large demand for space cooling—which is likely to increase with climate change. A common approach to dampen the indoor temperature fluctuations and thus reduce cooling energy demand is the use of thermal mass. However, the use of lightweight structures in many cities (e.g., high-rise structures, or for earthquake protection) precludes the use of traditional forms of thermal mass. Therefore, phase change materials (PCMs) are being widely developed as thermal energy storage systems for building applications. However, challenges such as leakage of PCMs in liquid state and their low thermal conductivity, still limit their applications in buildings. In this paper, we review the potential of Form or Shape-Stabilized Phase Change Materials (SSPCMs), which are developed by incorporating the PCM into a supporting matrix to prevent leakage in liquid state whilst improving thermal conductivity. We review different methods of preparation and the resultant thermal properties and chemical stability. We find good evidence in the literature for SSPCMs to reduce PCM leakage in liquid state, dampen indoor temperature fluctuations, and potentially alleviate peak energy demand by shifting peak loads to off-peak periods.

Enhancement of Separated Ultra Pure n-paraffin as Phase Change Materials (PCM) by W-Fe Bimetallic Oxides

2020 ◽  
Vol 10 (6) ◽  
pp. 817-826
Author(s):  
Fathi S. Soliman ◽  
Heba H. El-Maghrabi ◽  
Tamer Zaki ◽  
Amr A. Nada ◽  
Fouad Zahran
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Phase Change Materials ◽  
Optical Microscope ◽  
Paraffin Wax ◽  
Scanning Calorimetry ◽  
Latent Heat Storage ◽  
Paraffin Waxes ◽  
Bimetallic Oxides

Objective:: Six ultra pure Paraffin Waxes (PW) were successfully fractionated at 35°, 30°, 25°, 20°, 15° and 10°C. The bimetallic oxide (Ferberite) was successfully synthesized by Microwave assisted method. Methods: Enhanced Phase Change Materials (PCMs) were designed by loading W/Fe bimetallic oxides in the ultra pure PW matrix at 1, 2, 3, 4 and 5 wt. %. paraffin wax, W/Fe bimetallic oxide and the resultant composite blends were characterized by X-ray Diffraction (XRD), Gas Chromatography (GC), Deferential Scanning Calorimetry (DSC), Polarized Optical Microscope (POM), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). In addition to testing the thermal conductivity of the designed blends. According to SEM, DSC and POM data, the prepared nanocomposite was homogeneously dispersed into the selected PW matrix. Results: Data revealed that thermal conductivity of the designed composite increases with increasing the loading ratio of W-Fe bimetallic oxides. The total latent heat storage ΔHT of the initial sample was improved from 295.91 J/g to 311.48 J/g at 5 wt. % loading percent. Conclusion:: Thermal conductivity was improved from 8.54 to 21.77 W/m2k with increasing up to 255% in comparison with pure paraffin wax.

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