Thermal Behavior of a Building Provided With Phase-Change Materials on the Roof and Exposed to Solar Radiation

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Amina Mourid ◽  
Mustapha El Alami
Keyword(s):  
Heat Flux ◽  
Solar Radiation ◽  
Phase Change ◽  
Phase Change Materials ◽  
Solar Irradiation ◽  
Outer Face ◽  
Two Factors ◽  
Insulation Effect ◽  
Identical Test ◽  
Energy Efficiency Potential

This paper evaluates the effectiveness of phase change materials (PCMs) for the improvement of summer thermal comfort in lightweight buildings. Experiments have been carried out using PCM in the form of DuPont Energain wallboards in combination with a roof. Two factors influencing the effectiveness of PCM (thickness and location of PCM layer) have been investigated. An experimental study was carried out using two identical test cavities submitted to Casablanca weather. Thermal performance such as the roof surface temperatures and heat flux densities, through the envelope, have been studied. The results indicated that, compared with reference room (without PCM), the thermal storage allows solar radiation to be stored and released up to 6–7 h after solar irradiation; this has effects on both the reduction of daily temperature swings (up to 2 °C) and heat flux (more than 88%). It has been proved that the PCM with a thickness of 10.52 mm on the outer face of the roof has good thermal insulation effect and energy efficiency potential.

Sunlight-Activated Phase Change Materials for Controlled Heat Storage and Triggered Release

2021 ◽  
Author(s):  
Yuran Shi ◽  
Mihael Gerkman ◽  
Qianfeng Qiu ◽  
Shuren Zhang ◽  
Grace G. D. Han
Keyword(s):  
Phase Transition ◽  
Solar Radiation ◽  
Phase Change ◽  
Latent Heat ◽  
Photon Energy ◽  
Organic Phase ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Triggered Release

We report the design of photo-responsive organic phase change materials that can absorb filtered solar radiation to store both latent heat and photon energy via simultaneous phase transition and photo-isomerization....

scholarly journals Thermal Properties of PEG/Graphene Nanoplatelets (GNPs) Composite Phase Change Materials with Enhanced Thermal Conductivity and Photo-Thermal Performance

2018 ◽  
Vol 8 (12) ◽  
pp. 2613 ◽  
Author(s):  
Lihong He ◽  
Hao Wang ◽  
Hongzhou Zhu ◽  
Yu Gu ◽  
Xiaoyan Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Energy Conversion ◽  
Phase Change Materials ◽  
Near Infrared ◽  
Graphene Nanoplatelets ◽  
Solar Irradiation ◽  
Blending Method ◽  
Conduction Pathway ◽  
Composite Phase Change Materials

This paper mainly concentrates on the thermal conductivity and photo-thermal conversion performance of polyethylene glycol (PEG)/graphene nanoplatelets (GNPs) composite phase change materials (PCMs). The temperature-assisted solution blending method is used to prepare PCM with different mass fraction of GNPs. According to the scanning electron microscope (SEM), GNPs are evenly distributed in the PEG matrix, forming a thermal conduction pathway. The Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD) results show that the composites can still inherit the crystallization structure of PEG, moreover, there are only physical reactions between PEG and GNPs rather than chemical reactions. Differential scanning calorimeter (DSC) and thermal conductivity analysis results indicate that it may be beneficial to add a low loading ration of GNPs to obtain the suitable latent heat as well as enhance the thermal conductivity of composites. To investigate the change in the rheological behavior due to the effect of GNPs, the viscosity of the composites was measured as well. The photo-thermal energy conversion experiment indicates that the PEG/GNPs composites show better performance in photothermal energy conversion, moreover, the Ultraviolet-visible-Near Infrared spectroscopy is applied to illustrate the reasons for the higher absorption efficiency of PEG/GNPs for solar irradiation.

scholarly journals Phase Change Materials-Assisted Heat Flux Reduction: Experiment and Numerical Analysis

Energies ◽  
2016 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
Hussein Akeiber ◽  
Seyed Hosseini ◽  
Mazlan Wahid ◽  
Hasanen Hussen ◽  
Abdulrahman Mohammad
Keyword(s):  
Heat Flux ◽  
Numerical Analysis ◽  
Phase Change ◽  
Phase Change Materials ◽  
Reduction Experiment

Ultraviolet-Visible Light-Thermal Conversion Organic Solid-Liquid Phase-Change Materials

2013 ◽  
Vol 679 ◽  
pp. 29-34
Author(s):  
Yun Ming Wang ◽  
Bing Tao Tang ◽  
Shu Fen Zhang
Keyword(s):  
Energy Storage ◽  
Liquid Phase ◽  
Solar Radiation ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Thermal Conversion ◽  
Organic Solid ◽  
Solid Liquid

UV-vis light-driven organic solid-liquid phase change materials exhibited excellent performances of UV-vis light-harvesting, UV-vis light-thermal conversion and thermal energy storage, which is promoted by UV absorbing dye as an effective ‘‘photon capture and molecular heater’’ for direct and efficient use of solar radiation.

Experimental Study of Thermal Performance of a Reduced Scale Cavity Equipped With Phase Change Material: Study of the Optimal Phase Change Material Layer Location

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Ayoub Gounni ◽  
Mustapha El Alami ◽  
Mohamed Tahar Mabouk ◽  
Abdelhamid Kheiri
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Peak Heat Flux ◽  
Building Walls ◽  
Change Material ◽  
Reduced Scale ◽  
Material Study

Phase change materials (PCMs) used in the building walls constitute an attractive way to reduce the energy consumption and to increase the occupant's thermal comfort. However, there are some challenges to be faced among which the critical one is the PCM layer location allowing the greater heat flux reduction. In this work, the potential of PCM wallboards is evaluated experimentally using a heated reduced scale cavity including walls with or without PCM in a laboratory conditions. The cavity at reduced scale provides the flexibility to test most kinds of wall constructions in real time and allows faster installation and dismantling of the test walls. Three different PCM layer locations inside the walls are examined in terms of heat flux reduction and outside surface temperatures. The results confirm that the PCM layer reduces the peak heat flux compared to a reference wall (wall without PCM). Indeed, the PCM layer hugely affects the peak heat flux when it is placed on the inner face of the walls, near to the heat source. At this location, the peak heat flux reduction, compared to the reference wall, is 32.9%. Furthermore, for numerical validation purpose, the outside overall heat coefficient of the cavity outside walls is determined based on the experimental data.

Optimization of Filling Mass Fraction for Composite PCMs Based Thermal Management System

2017 ◽  
Author(s):  
Bofeng Shang ◽  
Jinyan Hu ◽  
Xingjian Yu ◽  
Bin Xie ◽  
Ruikang Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Phase Change ◽  
Latent Heat ◽  
Mass Fraction ◽  
Phase Change Materials ◽  
Matrix Material ◽  
Expanded Graphite ◽  
Working Time ◽  
Transfer Model

Phase Change Materials (PCMs) have been widely investigated as a cooling solution due to their significant latent heat capacity. However, the current PCMs generally suffer a low thermal conductivity, thus hindering the application of PCMs. Composite Phase Change Materials (CPCMs) filling with high thermal conductivity materials have been proposed to solve this issue. Nevertheless, the latent heat of the CPCMs decreases with the mass fraction of fillings, thus leading to a lower allowable working time under safe operating temperature. Therefore, an optimal filling mass fraction of CPCMs is in urgent needed to improve the application of CPCMs. In this study, we developed a one-dimensional conduction heat transfer model of CPCMs to predict the optimal filling mass fraction of CPCMs to realize the maximum allowable working time. The filling mass fraction was introduced into the model and the relationship between the thermal conductivity and latent heat was built. We adopted paraffin as the matrix material and Expanded Graphite (EG) as the thermal conductivity enhancer. The allowable working time of the CPCMs as the function of filling mass fraction was obtained. Based on the principle of the maximum allowable working time, the optimal filling mass fraction was calculated. Comparative experiments were also conducted to validate the accuracy of the prediction model. The parameters which affect the maximum allowable working temperature were also investigated, including input heat flux, safe temperature, and height of CPCMs. The results show that a higher heat flux and height requires a larger filling mass fraction, and it’s opposite for the safe temperature.

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