scholarly journals Indoor and Outdoor Performance of an Enhanced Photovoltaic Panel through Graphene/Fins/Phase Change Materials

2021 ◽  
Vol 11 (19) ◽  
pp. 8807
Author(s):  
Daniele Colarossi ◽  
Paolo Principi
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Cooling System ◽  
Melting Process ◽  
Photovoltaic Cell ◽  
Thermal Recovery ◽  
Solar Simulator ◽  
Reference Case ◽  
Photovoltaic Panel ◽  
Laboratory Characterization

The operative temperature of a photovoltaic cell influences the electric conversion yield. This can be enhanced by cooling the panel. Among the studied solutions, phase change materials (PCM) exploit latent heat and absorb a large amount of energy at a nearly constant temperature. PCMs suffer from a low thermal conductivity. Under these premises the paper presents a hybrid graphene/fins/PCM cooling system to maximize efficiency gains and thermal recovery. An indoor laboratory characterization, under a solar simulator, compares the proposed model with a reference one (an identical, simple PV module) under fixed environmental conditions. Outdoor tests investigate the performances of the two systems under natural conditions. Indoor results show that the front temperature of the proposed PCM integrated module is averagely 6 °C less, with a peak of 8 °C, than the reference case. This means an increase in the electric yield of about 3%. Outdoor investigations prove that, when the PCM is solid and during the melting phase, the proposed system is averagely 1.12 °C and 4.87 °C colder than the reference case, respectively. The thermal efficiency is 30% and 65%, respectively. Once the melting process is completed, the performance becomes worse, and the hybrid panel is almost 3 °C warmer than the simple panel.

scholarly journals Dynamics of Melting Process in Phase Change Material Windows Determined Based on Direct Light Transmission

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 721
Author(s):  
Dariusz Heim ◽  
Michał Krempski-Smejda ◽  
Pablo Roberto Dellicompagni ◽  
Dominika Knera ◽  
Anna Wieprzkowicz ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Light Transmission ◽  
Melting Process ◽  
Refraction Index ◽  
Light Transmittance ◽  
Reference Case ◽  
Solar Radiation Intensity ◽  
Direct Light ◽  
Change Material

Detailed analyses of melting processes in phase change material (PCM) glazing units, changes of direct transmittance as well as investigation of refraction index were provided based on laboratory measurements. The main goal of the study was to determine the direct light transmittance versus time under constant solar radiation intensity and stable temperature of the surrounding air. The experiment was conducted on a triple glazed unit with one cavity filled with a paraffin RT21HC as a PCM. The unit was installed in a special holder and exposed to the radiation from an artificial sun. The vertical illuminance was measured by luxmeters and compared with a reference case to determine the direct light transmittance. The transmittance was determined for the whole period of measurements when some specific artefacts were identified and theoretically explained based on values of refractive indexes for paraffins in the solid and liquid state, and for a glass. The melting process of a PCM in a glass unit was identified as a complex one, with interreflections and refraction of light on semi layers characterized by a different physical states (solid, liquid or mushy). These optical phenomena caused nonuniformity in light transmittance, especially when the PCM is in a mushy state. It was revealed that light transmittance versus temperature cannot be treated as a linear function.

Numerical Thermal Performance Investigation of an Electric Motor Passive Cooling System Employing Phase Change Materials

2021 ◽  
Author(s):  
Ali Deriszadeh ◽  
Filippo de Monte ◽  
Marco Villani
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Electric Motor ◽  
Phase Change Materials ◽  
Cooling System ◽  
Passive Cooling ◽  
Time Step ◽  
Cooling Performance ◽  
Passive Cooling System ◽  
Change Material

Abstract This study investigates the cooling performance of a passive cooling system for electric motor cooling applications. The metal-based phase change materials are used for cooling the motor and preventing its temperature rise. As compared to oil-based phase change materials, these materials have a higher melting point and thermal conductivity. The flow field and transient heat conduction are simulated using the finite volume method. The accuracy of numerical values obtained from the simulation of the phase change materials is validated. The sensitivity of the numerical results to the number of computational elements and time step value is assessed. The main goal of adopting the phase change material based passive cooling system is to maintain the operational motor temperature in the allowed range for applications with high and repetitive peak power demands such as electric vehicles by using phase change materials in cooling channels twisted around the motor. Moreover, this study investigates the effect of the phase change material container arrangement on the cooling performance of the under study cooling system.

Heat Transfer Enhancement of Finned Copper Foam/Paraffin Composite Phase Change Material

2021 ◽  
Vol 14 ◽  
Author(s):  
Tingting Wu ◽  
Yanxin Hu ◽  
Xianqing Liu ◽  
Changhong Wang ◽  
Zijin Zeng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Transfer Rate ◽  
Flow Resistance ◽  
Phase Change Materials ◽  
Heat Transfer Performance ◽  
Melting Process ◽  
Copper Foam ◽  
Composite Phase Change Material ◽  
Change Material

Background: The employment of Phase Change Materials (PCMs) provides a potential selection for heat dissipation and energy storage. The main reason that hinders the wide application is the low thermal conductivity of PCMs. Combining the proper metal fin and copper foam, the fin/composite phase change material (Fin-CPCM) structure with good performance could be obtained. However, the flow resistance of liquid paraffin among the porous structure has seldom been reported, which will significantly affect the thermal performance inside the metal foam. Furthermore, the presence of porous metal foam is primarily helpful for enhancing the heat transfer process from the bottom heat source. The heat transfer rate is slow due to the one-dimensional heat transfer from the bottom. It should be beneficial for improving the heat transfer performance by adding external fins. Therefore, in the present study, a modified structure by combining the metal fin and copper foam is proposed to further accelerate the melting process and improve the temperature uniformity of the composite. Objective: The purpose of this study is to research the differences in the heat transfer performance among pure paraffin, Composite Phase Change Materials (CPCM) and fin/Composite Phase Change Material (Fin-CPCM) under different heating conditions, and the flow resistance of melting paraffin in copper foam. Methods: To experimentally research the differences in the heat transfer performance among pure paraffin, CPCM and Fin-CPCM under different heating conditions, a visual experimental platform was set up, and the flow resistance of melting paraffin in copper foam was also analyzed. In order to probe into the limits of the heat transfer capability of composite phase change materials, the temperature distribution of PCMs under constant heat fluxes and constant temperature conditions was studied. In addition, the evolution of the temperature distributions was visualized by using the infrared thermal imager at specific points during the melting process. Results: The experimental results showed that the maximum temperature of Fin-CPCM decreased by 21°C under the heat flux of 1500W/m2 compared with pure paraffin. At constant temperature heating conditions, the melting time of Fin-CPCM at a temperature of 75°C is about 2600s, which is 65% less than that of pure paraffin. Due to the presence of the external fins, which brings the advantage of improving the heat transfer rate, the experimental result exhibited the most uniform temperature distribution. Conclusion: The addition of copper foam can accelerate the melting process. The addition of external fins brings the advantage of improving the heat transfer rate, and can make the temperature distribution more uniform.

Application of Phase Change Materials to Thermal Control of Electronic Modules: A Computational Study

1997 ◽  
Vol 119 (1) ◽  
pp. 40-50 ◽  
Author(s):  
D. Pal ◽  
Y. K. Joshi
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Cooling System ◽  
Computational Study ◽  
Power Level ◽  
Thermal Control ◽  
The Other ◽  
Three Dimensions ◽  
Temperature Isotherm ◽  
Laminate Thickness

A computational model is developed to predict the performance of phase change materials(PCMs) for passive thermal control of electronic modules during transient power variations or following an active cooling system failure. Two different ways of incorporating PCM in the module are considered. One is to place a laminate of PCM outside the multichip module, and the other is to place the PCM laminate between the substrate and the cold plate. Two different types of PCMs are considered. One is n-Eicosene, which is an organic paraffin, and the other one is a eutectic alloy of Bi/Pb/Sn/In. Computations are performed in three dimensions using a finite volume method. A single domain fixed grid enthalpy porosity method is used to model the effects of phase change. Effects of natural convection on the performance of PCM are also examined. Results are presented in the form of time-wise variations of maximum module temperature, isotherm contours, velocity vectors, and melt front locations. Effects of PCM laminate thickness and power levels are studied to assess the amount of PCM required for a particular power level. The results show that the PCMs are an effective option for passive cooling of high density electronic modules for transient periods.

Air-cooling system based on phase change materials for a vehicle cabin

2020 ◽  
Author(s):  
Sangeetha Krishnamoorthi ◽  
L. Prabhu ◽  
Glen Kuriakose ◽  
Dave Jose lewis ◽  
J. Harikrishnan
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Cooling System ◽  
Air Cooling ◽  
Vehicle Cabin ◽  
Air Cooling System

Detailed Numerical Modeling of a Hybrid PCM-Air Heat Sink

2013 ◽  
Author(s):  
Y. Kozak ◽  
G. Ziskind
Keyword(s):  
Numerical Modeling ◽  
Phase Change ◽  
Heat Sink ◽  
Phase Change Materials ◽  
Void Formation ◽  
Solidification Process ◽  
Melting Process ◽  
Significant Rise ◽  
Air Interface ◽  
Vof Model

The ability of phase-change materials (PCMs) to absorb large amounts of heat without significant rise of their temperature during the melting process may be utilized in thermal energy storage and passive thermal management. This paper deals with numerical modeling of a hybrid PCM-air heat sink, in which heat may be either absorbed by the PCM stored in compartments with conducting walls, or dissipated to the air using fins, or both. Under the assumptions of perfect insulation (except for the air fins), identity and symmetry between all PCM channels, and negligible 3-D boundary effects, a 2-D model of the problem for half a PCM compartment of the heat sink is solved, saving calculation time and yet taking into account the essential physical phenomena. A commercial program, ANSYS Fluent, is used in order to solve the governing conservation equations. Phase-change is solved using the enthalpy-porosity method. PCM-air interface is modeled using the volume-of-fluid (VOF) approach. The model takes into account natural convection in the liquid PCM and air, volume change, phase- and temperature-dependence of thermal properties, and PCM-air interface interaction. Various scenarios for the hybrid heat sink operation are simulated and compared. The difference in the melting patterns is analyzed for the cases of heating with and without the fan operating. The solidification process with the fan operating is also simulated. It is shown that the VOF model enables simulating realistic void formation in the solidification process.

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