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.

Experimental Study of Heat Transfer in a Reduced Scale Cavity Incorporating Phase Change Material Into Its Vertical Walls

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Ayoub Gounni ◽  
Mustapha El Alami
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Phase Change ◽  
Phase Change Material ◽  
Heat Fluxes ◽  
Surface Temperatures ◽  
Different Depths ◽  
Vertical Walls ◽  
Change Material ◽  
Reduced Scale

In order to really assess the thermal performance of a wall incorporating phase change material (PCM), a reduced scale cavity has been monitored during two heating cycles. For each cycle, the heat source inside the test cell is switched “on” for 5 h and its setpoint is 38 °C and then switched off for 4 h. The outdoor air temperature is kept constant at a low temperature of 20 °C. Two walls are equipped with a PCM layer at different depths in order to study the optimal PCM location. The two other walls are wooden and glass to model a real building. The comparison between the four walls is made based on the absorbed heat fluxes and outside surface temperatures. The results show that the location of the PCM close to the heat source reaches its melting temperature and then reduces the surface temperature. At this location, the PCM layer stores the major part of the inlet heat flux. It takes 10 h to release the absorbed heat flux. However, the PCM layer, practically, does not have an effect on the surface temperatures and absorbed heat fluxes, when it is placed far from the heat source.

scholarly journals Application of Phase Change Material and Artificial Neural Networks for Smoothing of Heat Flux Fluctuations

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3531
Author(s):  
Tomasz Tietze ◽  
Piotr Szulc ◽  
Daniel Smykowski ◽  
Andrzej Sitka ◽  
Romuald Redzicki
Keyword(s):  
Neural Networks ◽  
Heat Flux ◽  
Artificial Neural Networks ◽  
Phase Change ◽  
Mass Flow Rate ◽  
Phase Change Material ◽  
Flow Rate ◽  
Smoothing Effect ◽  
Artificial Neural ◽  
Change Material

The paper presents an innovative method for smoothing fluctuations of heat flux, using the thermal energy storage unit (TES Unit) with phase change material and Artificial Neural Networks (ANN) control. The research was carried out on a pilot large-scale installation, of which the main component was the TES Unit with a heat capacity of 500 MJ. The main challenge was to smooth the heat flux fluctuations, resulting from variable heat source operation. For this purpose, a molten salt phase change material was used, for which melting occurs at nearly constant temperature. To enhance the smoothing effect, a classical control system based on PID controllers was supported by ANN. The TES Unit was supplied with steam at a constant temperature and variable mass flow rate, while a discharging side was cooled with water at constant mass flow rate. It was indicated that the operation of the TES Unit in the phase change temperature range allows to smooth the heat flux fluctuations by 56%. The tests have also shown that the application of artificial neural networks increases the smoothing effect by 84%.

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.

Modelling of a Phase Change Material melting process heated from below using spectral collocation methods

2014 ◽  
Vol 24 (3) ◽  
pp. 697-734 ◽  
Author(s):  
Jean Batina ◽  
Serge Blancher ◽  
Tarik Kouskou
Keyword(s):  
Heat Flux ◽  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Textile Industry ◽  
Present Model ◽  
Good Accuracy ◽  
Content Type ◽  
Energy Equations ◽  
Change Material

Purpose – Mathematical and numerical models are developed to study the melting of a Phase Change Material (PCM) inside a 2D cavity. The bottom of the cell is heated at constant and uniform temperature or heat flux, assuming that the rest of the cavity is completely adiabatic. The paper used suitable numerical methods to follow the interface temporal evolution with a good accuracy. The purpose of this paper is to show how the evolution of the latent energy absorbed to melt the PCM depends on the temperature imposed on the lower wall of the cavity. Design/methodology/approach – The problem is written with non-homogeneous boundary conditions. Momentum and energy equations are numerically solved in space by a spectral collocation method especially oriented to this situation. A Crank-Nicolson scheme permits the resolution in time. Findings – The results clearly show the evolution of multicellular regime during the process of fusion and the kinetics of phase change depends on the boundary condition imposed on the bottom cell wall. Thus the charge and discharge processes in energy storage cells can be controlled by varying the temperature in the cell PCM. Substantial modifications of the thermal convective heat and mass transfer are highlighted during the transient regime. This model is particularly suitable to follow with a good accuracy the evolution of the solid/liquid interface in the process of storage/release energy. Research limitations/implications – The time-dependent physical properties that induce non-linear coupled unsteady terms in Navier-Stokes and energy equations are not taken into account in the present model. The present model is actually extended to these coupled situations. This problem requires smoother geometries. One can try to palliate this disadvantage by constructing smoother approximations of non-smooth geometries. The augmentation of polynomials developments orders increases strongly the computing time. When the external heat flux or temperature imposed at the PCM is much greater than the temperature of the PCM fusion, one must choose carefully some data to assume the algorithms convergence. Practical implications – Among the areas where this work can be used, are: buildings where the PCM are used in insulation and passive cooling; thermal energy storage, the PCM stores energy by changing phase, solid to liquid (fusion); cooling and transport of foodstuffs or pharmaceutical or medical sensitive products, the PCM is used in the food industry, pharmaceutical and medical, to minimize temperature variations of food, drug or sensitive materials; and the textile industry, PCM materials in the textile industry are used in microcapsules placed inside textile fibres. The PCM intervene to regulate heat transfer between the body and the outside. Originality/value – The paper's originality is reflected in the precision of its results, due to the use of a high-accuracy numerical approximation based on collocation spectral methods, and the choice of Chebyshev polynomials basis in both axial and radial directions.

scholarly journals Performance Improvement of a Household Refrigerator using Phase Change Material

2021 ◽  
Vol 16 (1) ◽  
pp. 032-041
Author(s):  
Pradeep N ◽  
Somesh Subramanian S
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Storage System ◽  
Thermal Storage ◽  
Latent Heat Storage ◽  
Peak Loads ◽  
Change Material

Thermal energy storage through phase change material has been used for wide applications in the field of air conditioning and refrigeration. The specific use of this thermal storage has been for energy storage during low demand and release of this energy during peak loads with potential to provide energy savings due to this. The principle of latent heat storage using phase change materials (PCMs) can be incorporated into a thermal storage system suitable for using deep freezers. The evaporator is covered with another box which has storage capacity or passage through phase change material. The results revealed that the performance is increased from 3.2 to 3.5 by using PCM.

Dissipative particle dynamics study of nano-encapsulated thermal energy storage phase change material

RSC Advances ◽  
2014 ◽  
Vol 4 (74) ◽  
pp. 39552-39557 ◽  
Author(s):  
Zhonghao Rao ◽  
Xinyu You ◽  
Yutao Huo ◽  
Xinjian Liu
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Thermophysical Properties ◽  
Phase Change Materials ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Change Material

The nano-encapsulated phase change materials (PCM), which have several good thermophysical properties, were proposed as potential for thermal energy storage.

Phase-Change Materials and Building Energy Saving

2013 ◽  
Vol 683 ◽  
pp. 106-109
Author(s):  
Xiao Gang Zhao ◽  
Ying Pan
Keyword(s):  
Phase Change ◽  
Energy Saving ◽  
Phase Change Material ◽  
Building Materials ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Building Energy ◽  
Storage Performance ◽  
Building Energy Saving ◽  
Change Material

Phase change materials, abbreviated as PCM, due to the excellent heat storage performance, have been used as building materials and got more and more attention in recent years. The article introduce the building application of phase change material, and discuss its contribution to the building energy saving.

scholarly journals Effect of phase change material using in building thermal comfort applications through several climate conditions.

2020 ◽  
Vol 170 ◽  
pp. 01007
Author(s):  
Marwa El Yassi ◽  
Ikram El Abbassi ◽  
Alexandre Pierre ◽  
Yannick Melinge
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Phase Change Material ◽  
Phase Change Materials ◽  
Chemical Change ◽  
Thermal Inertia ◽  
Temperature Fluctuations ◽  
High Energy ◽  
Climate Conditions ◽  
Change Material

Nowadays, buildings sector contributes to climate change by consuming a considerable amount of energy to afford thermal comfort for occupants. Passive cooling techniques are a promising solution to increase the thermal inertia of building envelopes, and reduce temperature fluctuations. The phase change materials, known as PCM, can be efficiently employed to this purpose, because of their high energy storage density. Among the various existing solutions, the present study is dedicated to solid-liquid phase change materials. Temperature evolution (according to their defined temperature range) induces the chemical change of the material and its state. For building applications, the chemical transition can be accomplished from liquid to solid (solidification) and from solid to liquid (melting). In fact, this paper presents a comparative thermal analysis of several test rooms with and without phase change materials embedded in a composite wallboard in different climates. The used PCM consist in a flexible sheet of 5 mm thickness (Energain, manufactured by the company DuPont de Nemours). The main properties of such a commercial solution have been delivered by the manufacturer and from analyses. The room model was validated using laboratory instrumentations and measurements of a test room in four cities: Lyon; Reading and Casablanca. Results indicate that this phase change material board can absorb heat gains and also reduce the indoor air temperature fluctuations during daytime. The aim of the study is to show the benefits of this layer with phase change material and compare it in different climatic zones.

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

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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