Comparison of Stratification in a Water Tank and a PCM-Water Tank

2007 ◽  
Author(s):  
A. Castell ◽  
C. Sole´ ◽  
M. Medrano ◽  
M. Nogue´s ◽  
L. F. Cabeza
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Temperature Change ◽  
High Energy ◽  
Hot Water ◽  
The Other ◽  
High Energy Density ◽  
Water Tank ◽  
Charging And Discharging Processes ◽  
Change Material

Most of the storage systems available on the market use water as storage medium. Enhancing the storage performance is necessary to increase the performance of most systems. The stratification phenomenon is employed to improve the efficiency of storage tanks. Heat at an intermediate temperature, not high enough to heat up the top layer, can still be used to heat the lower, colder layers. There are a lot of parameters to study the stratification in a water tank such as the Mix Number and the Richardson Number among others. The idea studied here was to use these stratification parameters to compare two tanks with the same dimensions during charging and discharging processes. One of them is a traditional water tank and the other is a PCM-water (a water tank with a Phase Change Material). A PCM is good because it has high energy density if there is a small temperature change, since then the latent heat is much larger than the sensible heat. On the other hand, the temperature change in the top layer of a hot water store with stratification is usually small as it is held as close as possible at or above the temperature for usage. In the system studied the Phase Change Material is placed at the top of the tank, therefore the advantages of the stratification still remain. The aim of this work is to demonstrate that the use of PCM in the upper part of a water tank holds or improves the benefit of the stratification phenomenon.

Comparison of Stratification in a Water Tank and a PCM-Water Tank

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
A. Castell ◽  
C. Solé ◽  
M. Medrano ◽  
M. Nogués ◽  
L. F. Cabeza
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Materials ◽  
High Energy ◽  
Hot Water ◽  
The Other ◽  
High Energy Density ◽  
Water Tank ◽  
Charging And Discharging Processes ◽  
Thermal Energy Storage Systems

Most of the thermal energy storage systems available on the market use water as a storage medium. The improvement of the storage efficiency results in a higher performance of the whole system, and thermal stratification is commonly used for this purpose. On the other hand, in applications with small temperature changes, phase change materials (PCMs) provide high energy density since the latent heat is much larger than the sensible heat. This is the case of stratified hot water tanks, where the temperature change in the top layer is small as it is held close to the usage temperature. The benefits of using PCMs in a water tank, in terms of energy storage density, have been demonstrated before. The time with available hot water is increased because of the energy stored in the PCMs. The aim of this work is to demonstrate that the use of PCMs in the upper part of a water tank holds or improves the benefit of the stratification phenomenon. Two tanks with the same dimensions were compared during charging and discharging processes. One of them is a traditional water tank and the other is a PCM-water tank (a water tank with a phase change material placed at the top).

Super-Cooling Suppression of Microencapsulated PCM

2014 ◽  
Vol 1070-1072 ◽  
pp. 422-426
Author(s):  
Shan Lv ◽  
Zhong Zhu Qiu
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Supply And Demand ◽  
High Energy ◽  
High Energy Density ◽  
Core Material ◽  
Microencapsulated Phase Change Material ◽  
State Changes ◽  
Main Barrier ◽  
Change Material

Microencapsulated Phase change material can absorb and release large amounts of latent heat over a defined temperature range as its physical state changes. The microencapsulated PCM has high energy density and isothermal behavior during charging and discharging and can avoid the contradiction of the energy supply and demand unbalance in time and space. Meanwhile, the shell can separate the phase change material from the outside environment in order to protect the core material. But the super-cooling problem is a main barrier for microencapsulated PCM application. So this paper talks about how to dealing with super-cooling based on related literatures and gives an overview about the methodology in this area.

scholarly journals Optimization of Phase-Change Material–Elastomer Composite and Integration in Kirigami-Inspired Voxel-Based Actuators

2021 ◽  
Vol 8 ◽  
Author(s):  
Gilles Decroly ◽  
Romain Raffoul ◽  
Clara Deslypere ◽  
Paul Leroy ◽  
Louis Van Hove ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Close Contact ◽  
Low Cost ◽  
High Energy ◽  
Design Approach ◽  
High Energy Density ◽  
Complex Tasks ◽  
Change Material ◽  
Actuation Strain

Phase-change material–elastomer composite (PCMEC) actuators are composed of a soft elastomer matrix embedding a phase-change fluid, typically ethanol, in microbubbles. When increasing the temperature, the phase change in each bubble induces a macroscopic expansion of the matrix. This class of actuators is promising for soft robotic applications because of their high energy density and actuation strain, and their low cost and easy manufacturing. However, several limitations must be addressed, such as the high actuation temperature and slow actuation speed. Moreover, the lack of a consistent design approach limits the possibility to build PCMEC-based soft robots able to achieve complex tasks. In this work, a new approach to manufacture PCMEC actuators with different fluid–elastomer combinations without altering the quality of the samples is proposed. The influence of the phase-change fluid and the elastomer on free elongation and bending is investigated. We demonstrate that choosing an appropriate fluid increases the actuation strain and speed, and decreases the actuation temperature compared with ethanol, allowing PCMECs to be used in close contact with the human body. Similarly, by using different elastomer materials, the actuator stiffness can be modified, and the experimental results showed that the curvature is roughly proportional to the inverse of Young’s modulus of the pure matrix. To demonstrate the potential of the optimized PCMECs, a kirigami-inspired voxel-based design approach is proposed. PCMEC cubes are molded and reinforced externally by paper. Cuts in the paper induce anisotropy into the structure. Elementary voxels deforming according to the basic kinematics (bending, torsion, elongation, compression and shear) are presented. The combination of these voxels into modular and reconfigurable structures could open new possibilities towards the design of flexible robots able to perform complex tasks.

scholarly journals A Novel Approach on the Advancement in Polymer Phase Change Material in Solar Energy

2022 ◽  
Vol 2022 ◽  
pp. 1-8
Author(s):  
G. Jegan ◽  
P. Ramani ◽  
T. J. Nagalakshmi ◽  
S. Chitra ◽  
T. Samraj Lawrence
Keyword(s):  
Solar Energy ◽  
Phase Change ◽  
Phase Change Material ◽  
High Energy ◽  
High Energy Density ◽  
Energy Output ◽  
Polymer Phase ◽  
Diverse Range ◽  
Novel Approach ◽  
Change Material

A wide interest has been shown in the application of solar energy in recent times. This motivated the researchers to make a development in the approach of solar energy, but there are different technologies like MPPT, CPG, and grid mode that have been used to maintain a constant temperature. Among these, phase change material has been used to regulate the temperature in the system. Solar energy is becoming an essential approach for increasing the efficiency of thermal energy conversion and utilizing polymeric step change composites, which have attracted extremely large interest in recent years due to their advantages of high energy density and powerful energy output stability. A plethora of reviews and reports have been published to compile the diverse range of PCMs made available for various applications. PCMs are created by improving thermophysical thermodynamic stability, latent heat, and heat capacity. Furthermore, the possible applications of polymer phase PCMs in a variety of fields, such as energy storage devices, thermal corrective action, and temperature-controlled drug carriers, are detailed. In this paper, a novel approach on the advancement of nanoconfined phase change material is defined along with the application of the solar energy system.

scholarly journals Optimized Modeling and Design of a PCM-Enhanced H2 Storage

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Andrea Luigi Facci ◽  
Marco Lauricella ◽  
Sauro Succi ◽  
Vittorio Villani ◽  
Giacomo Falcucci
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Power Density ◽  
Latent Heat ◽  
Metal Hydride ◽  
Renewable Energy Sources ◽  
High Energy ◽  
High Energy Density ◽  
Change Material

Thermal and mechanical energy storage is pivotal for the effective exploitation of renewable energy sources, thus fostering the transition to a sustainable economy. Hydrogen-based systems are among the most promising solutions for electrical energy storage. However, several technical and economic barriers (e.g., high costs, low energy and power density, advanced material requirements) still hinder the diffusion of such solutions. Similarly, the realization of latent heat storages through phase change materials is particularly attractive because it provides high energy density in addition to allowing for the storage of the heat of fusion at a (nearly) constant temperature. In this paper, we posit the challenge to couple a metal hydride H2 canister with a latent heat storage, in order to improve the overall power density and realize a passive control of the system temperature. A highly flexible numerical solver based on a hybrid Lattice Boltzmann Phase-Field (LB-PF) algorithm is developed to assist the design of the hybrid PCM-MH tank by studying the melting and solidification processes of paraffin-like materials. The present approach is used to model the storage of the heat released by the hydride during the H2 loading process in a phase change material (PCM). The results in terms of Nusselt numbers are used to design an enhanced metal-hydride storage for H2-based energy systems, relevant for a reliable and cost-effective “Hydrogen Economy”. The application of the developed numerical model to the case study demonstrates the feasibility of the posited design. Specifically, the phase change material application significantly increases the heat flux at the metal hydride surface, thus improving the overall system power density.

scholarly journals Life Cycle Assessment of the Use of Phase Change Material in an Evacuated Solar Tube Collector

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4146
Author(s):  
Agnieszka Jachura ◽  
Robert Sekret
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impact ◽  
Phase Change ◽  
Phase Change Material ◽  
Solar Collector ◽  
Hot Water ◽  
Production Operation ◽  
Management Scenarios ◽  
Change Material

This paper presents an environmental impact assessment of the entire cycle of existence of the tube-vacuum solar collector prototype. The innovativeness of the solution involved using a phase change material as a heat-storing material, which was placed inside the collector’s tubes-vacuum. The PCM used in this study was paraffin. The system boundaries contained three phases: production, operation (use phase), and disposal. An ecological life cycle assessment was carried out using the SimaPro software. To compare the environmental impact of heat storage, the amount of heat generated for 15 years, starting from the beginning of a solar installation for preparing domestic hot water for a single-family residential building, was considered the functional unit. Assuming comparable production methods for individual elements of the ETC and waste management scenarios, the reduction in harmful effects on the environment by introducing a PCM that stores heat inside the ETC ranges from 17 to 24%. The performed analyses have also shown that the method itself of manufacturing the materials used for the construction of the solar collector and the choice of the scenario of the disposal of waste during decommissioning the solar collector all play an important role in its environmental assessment. With an increase in the application of the advanced technologies of materials manufacturing and an increase in the amount of waste subjected to recycling, the degree of the solar collector’s environmental impact decreased by 82% compared to its standard manufacture and disposal.

Thermal Behavior of Phase Change Material During Charging Inside a Finned Cylindrical Latent Heat Energy Storage System: Effects of the Arrangement and Number of Fins

2010 ◽  
Author(s):  
Dominic Groulx ◽  
Wilson Ogoh
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Storage System ◽  
Heat Energy ◽  
Hot Water ◽  
Heat Of Fusion ◽  
Melting Front ◽  
Change Material

One way of storing thermal energy is through the use of latent heat energy storage systems. One such system, composed of a cylindrical container filled with paraffin wax, through which a copper pipe carrying hot water is inserted, is presented in this paper. It is shown that the physical processes encountered in the flow of water, the heat transfer by conduction and convection, and the phase change behavior of the phase change material can be modeled numerically using the finite element method. Only charging (melting) is treated in this paper. The appearance and the behavior of the melting front can be simulated by modifying the specific heat of the PCM to account for the increased amount of energy, in the form of latent heat of fusion, needed to melt the PCM over its melting temperature range. The effects of adding fins to the system are also studied, as well as the effects of the water inlet velocity.

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