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.

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.

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 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 vegetable fat: A low-cost bio-based phase change material for thermal energy storage in buildings

2019 ◽  
Vol 21 ◽  
pp. 222-229 ◽  
Author(s):  
Lisa Boussaba ◽  
Said Makhlouf ◽  
Amina Foufa ◽  
Gilles Lefebvre ◽  
Laurent Royon
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Low Cost ◽  
Change Material ◽  
Vegetable Fat

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.

A Design Method for Shape Memory Alloy Actuators Accounting for Cyclic Shakedown With Constrained Allowable Strain

2010 ◽  
Author(s):  
WonHee Kim ◽  
Brian M. Barnes ◽  
Jonathan E. Luntz ◽  
Diann E. Brei
Keyword(s):  
Design Method ◽  
Mechanical Strain ◽  
High Energy ◽  
Design Guidelines ◽  
Design Approach ◽  
High Energy Density ◽  
Interface Position ◽  
Design Variables ◽  
Graphical Design ◽  
Actuation Strain

The high energy density actuation potential of SMA wire is tempered by conservative design guidelines set to mitigate complex factors such as functional fatigue (shakedown). Shakedown causes problems of stroke loss and interface position drift between the system and the SMA wire under higher stress levels if the wire does not undergo a pre-installation shakedown procedure. Limiting actuation strain has been reported as reducing shakedown as well as increasing fatigue life. One approach to limit actuation strain is using a mechanical strain limiter which sets a fixed Martensite strain position — useful for the development of in-device shakedown procedures which eliminates time consuming pre-installation shakedown procedures. This paper presents a new graphical design approach for SMA wire actuators which accounts for shakedown with the use of mechanical strain limiters to enable higher stress designs to maximize actuator performance. Experimental data on the effect of strain limiters along with stroke and work density contours form the basis for the new graphical design method. For each independent mechanical strain limiter, the maximum of the individual post-shakedown austenite curves at a range of applied stress are combined into a conglomerate stabilization design curve. These curves over a set of mechanical strain limiters provide steady state performance prediction for SMA actuation, effectively decoupling the shakedown material performance from design variables that affect the shakedown. The use and benefits of this new design approach are demonstrated with a common constant force actuator design example. This new design approach, which accounts for shakedown, supports design of SMA actuators at higher stresses with more economical use of material/power, and enables the utilization of strain limiters for cost saving in-device shakedown procedures.

scholarly journals Usage of EMBRACETMin Gujarat, India: Survey of Paediatricians

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Somashekhar Nimbalkar ◽  
Harshil Patel ◽  
Ashish Dongara ◽  
Dipen V. Patel ◽  
Satvik Bansal
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Phase Change ◽  
Phase Change Material ◽  
Constant Temperature ◽  
Low Cost ◽  
Kangaroo Mother Care ◽  
Change Material ◽  
At Home

Aim. EMBRACETMis an innovative, low cost infant warmer for use in neonates. It contains phase change material, which stays at constant temperature for 6 hours. We surveyed paediatricians using EMBRACETMregarding benefits, risks, and setup in which it was used in Gujarat.Methods. Questionnaire was administered telephonically to 52 out of 53 paediatricians.Results. EMBRACETMwas used for an average of 8.27 (range of 3–18, SD = 3.84) months by paediatricians. All used it for thermoregulation during transfers, for average (SD) duration of 42 (0.64) m per transfer, 62.7% used it at mother’s side for average (SD) 11.06 (7.89) h per day, and 3.9% prescribed it at home. It was used in low birth weight neonates only by 56.9% while 43.1% used it for all neonates. While hyperthermia was not reported, 5.9% felt that EMBRACETMdid not prevent hypothermia. About 54.9% felt that they could not monitor the newborn during EMBRACETMuse. Of paediatricians who practiced kangaroo mother care (KMC), 7.7% have limited/stopped/decreased the practice of KMC and substituted it with EMBRACETM.Conclusions. EMBRACETMwas acceptable to most but concerns related to monitoring neonates and disinfection remained. Most paediatricians felt that it did not hamper KMC practice.

Sign in / Sign up

Export Citation Format

Share Document