scholarly journals CFD-Simulation Assisted Design of Elastocaloric Regenerator Geometry

2020 ◽  
Vol 12 (21) ◽  
pp. 9013
Author(s):  
Kristina Navickaitė ◽  
Michael Penzel ◽  
Christian Bahl ◽  
Kurt Engelbrecht ◽  
Jaka Tušek ◽  
...  
Keyword(s):  
Flat Plate ◽  
World Wide ◽  
Cfd Simulation ◽  
Volume Ratio ◽  
Cooling Power ◽  
Promising Alternative ◽  
Compression Cycle ◽  
Elastocaloric Cooling ◽  
Conventional Cooling ◽  
Vapour Compression

Elastocaloric cooling is a promising alternative to conventional cooling using the vapour compression cycle, with potentially higher theoretical exergy efficiency. Nevertheless, there is a number of challenges to be tackled before the technology can be commercially available world-wide. In this study, the potential of double corrugated regenerators to enhance the cooling power of an elastocaloric device that would be operating under compression loading was investigated. The numerical performances of two types of double corrugated geometries are presented and compared to a flat plate regenerator as a reference. The double corrugated geometry significantly increases the surface area to volume ratio and convection of the regenerator, which allows an increase in the power density of the device.

scholarly journals Performance Comparison of Organic Rankine Cycle and Vapour Compression Cycle Hybrid Cooling-Heating System using Subcritical or Supercritical Working Fluid

2018 ◽  
Vol 202 ◽  
pp. 02008
Author(s):  
Ke San Yam ◽  
Raja Wahiduzzaman Bin Raja Ismail ◽  
Vincent Chieng Chen Lee ◽  
Hyung Chul Jung
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Heating System ◽  
Energy Output ◽  
Working Fluid ◽  
Cooling Power ◽  
Split Ratio ◽  
Compression Cycle ◽  
Self Powered ◽  
Vapour Compression

This paper presents a mathematical modelling on the evaluation of cooling, heating and power performance of a hybrid system of Organic Rankine Cycle and Vapour Compression Cycle. The system is assumed to be powered through solar parabolic trough collector and is able to generate a cooling power of 10 kW. Refrigerants R134a or R245fa are chosen as the working fluid of the system. The system is constructed using commercial energy modelling tool AspenPlus. Analysis is performed to determine the effect of changing the mass flow rate split ratio on the energy output. The effect of using subcritical and supercritical working fluid is also compared. Particular attention is paid toward the condition where the power output is equivalent to the energy consumption in view of creating a self-powered cooling and heating system. The result shows that the coefficient of performance for system using R245fa is higher compared to that using R134a. However, the system using R134a allows a self-powered cooling and heating system to be achieved to be achieve at a much higher mass split ratio, resulting the system to be 35% more efficient in the performance.

scholarly journals A multistage elastocaloric refrigerator and heat pump with 28 K temperature span

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ryan Snodgrass ◽  
David Erickson
Keyword(s):  
Single Stage ◽  
Maximum Temperature ◽  
Vapor Compression ◽  
Cooling Systems ◽  
Promising Alternative ◽  
Elastocaloric Effect ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Stage System ◽  
Elastocaloric Cooling

AbstractElastocaloric refrigerators are a promising alternative to the vapor compression cycle because they do not require refrigerants with high global warming potential. However, these coolers have yet to achieve temperatures low enough to — for example — be used as standard household refrigerators. We built one-stage, two-stage, and three-stage elastocaloric cooling systems to determine if staging of the elastocaloric effect could significantly expand temperature span. Our three-stage system achieved 1.5 times the maximum temperature span of our single-stage system, and produced the highest temperature span of any elastocaloric device to-date at 28.3 °C, where previously the record was 19.9 °C. Interestingly, we found that multistage systems can achieve equivalent temperature spans but at higher coefficients of performance compared to similarly-constructed single-stage systems.

scholarly journals Current Update of Collagen Nanomaterials—Fabrication, Characterisation and Its Applications: A Review

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 316
Author(s):  
Samantha Lo ◽  
Mh Busra Fauzi
Keyword(s):  
Mechanical Stability ◽  
Health Management ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Cartilage Regeneration ◽  
Nerve Tissue ◽  
Electrospinning Technique ◽  
Engineering Technology ◽  
Promising Alternative ◽  
Tissue Repair And Regeneration

Tissue engineering technology is a promising alternative approach for improvement in health management. Biomaterials play a major role, acting as a provisional bioscaffold for tissue repair and regeneration. Collagen a widely studied natural component largely present in the extracellular matrix (ECM) of the human body. It provides mechanical stability with suitable elasticity and strength to various tissues, including skin, bone, tendon, cornea and others. Even though exogenous collagen is commonly used in bioscaffolds, largely in the medical and pharmaceutical fields, nano collagen is a relatively new material involved in nanotechnology with a plethora of unexplored potential. Nano collagen is a form of collagen reduced to a nanoparticulate size, which has its advantages over the common three-dimensional (3D) collagen design, primarily due to its nano-size contributing to a higher surface area-to-volume ratio, aiding in withstanding large loads with minimal tension. It can be produced through different approaches including the electrospinning technique to produce nano collagen fibres resembling natural ECM. Nano collagen can be applied in various medical fields involving bioscaffold insertion or fillers for wound healing improvement; skin, bone, vascular grafting, nerve tissue and articular cartilage regeneration as well as aiding in drug delivery and incorporation for cosmetic purposes.

Haeckelite Phosphorous: An Emerging 2D Allotrope of Phosphorous for Potential Use in LIBs/SIBs

2021 ◽  
Author(s):  
Gayatree Barik ◽  
Sourav Pal
Keyword(s):  
2D Materials ◽  
Essential Feature ◽  
Volume Ratio ◽  
Promising Alternative ◽  
Materials Used ◽  
Potential Use

A large surface-to-volume ratio is an essential feature of 2D materials used in many potential electronic applications. This work proposed that the Haeckelite structured phosphorous can be another promising alternative...

Optimisation of ammonia refrigeration system by manipulating parameters of vapour compression cycle

2020 ◽  
Vol 6 (3) ◽  
pp. 275
Author(s):  
Arshad Hussain ◽  
Fareeha Shahdab ◽  
Sarah Farrukh ◽  
Luqman Rafiq ◽  
Uzair Ibrahim ◽  
...  
Keyword(s):  
Refrigeration System ◽  
Compression Cycle ◽  
Vapour Compression

scholarly journals Elastocaloric Cooling: State-of-the-art and Future Challenges in Designing Regenerative Elastocaloric Devices

2019 ◽  
Vol 65 (11-12) ◽  
pp. 615-630 ◽  
Author(s):  
Parham Kabirifar ◽  
Andrej Žerovnik ◽  
Žiga Ahčin ◽  
Luka Porenta ◽  
Miha Brojan ◽  
...  
Keyword(s):  
State Of The Art ◽  
The Third ◽  
Recovery Potential ◽  
Elastocaloric Effect ◽  
Work Recovery ◽  
Future Challenges ◽  
Released Energy ◽  
Elastocaloric Cooling ◽  
Cooling Technology ◽  
Vapour Compression

The elastocaloric cooling, utilizing latent heat associated with martensitic transformation in shape-memory alloys, is being considered in the recent years as one of the most promising alternatives to vapour compression cooling technology. It can be more efficient and completely harmless to the environment and people. In the first part of this work, the basics of the elastocaloric effect (eCE) and the state-of-the-art in the field of elastocaloric materials and devices are presented. In the second part, we are addressing crucial challenges in designing active elastocaloric regenerators, which are currently showing the largest potential for utilization of eCE in practical devices. Another key component of elastocaloric technology is a driver mechanism that needs to provide loading for active elastocaloric regenerators in an efficient way and recover the released energy during their unloading. Different driver mechanisms are reviewed and the work recovery potential is discussed in the third part of this work.

scholarly journals Exploiting radiative cooling for uninterrupted 24-hour water harvesting from the atmosphere

2021 ◽  
Vol 7 (26) ◽  
pp. eabf3978
Author(s):  
Iwan Haechler ◽  
Hyunchul Park ◽  
Gabriel Schnoering ◽  
Tobias Gulich ◽  
Mathieu Rohner ◽  
...  
Keyword(s):  
Radiative Heat ◽  
Outer Space ◽  
Continuous Production ◽  
Solar Irradiation ◽  
Cooling Power ◽  
Water Harvesting ◽  
Atmospheric Water ◽  
Promising Alternative ◽  
Mass Fluxes ◽  
Power Enhancement

Atmospheric water vapor is ubiquitous and represents a promising alternative to address global clean water scarcity. Sustainably harvesting this resource requires energy neutrality, continuous production, and facility of use. However, fully passive and uninterrupted 24-hour atmospheric water harvesting remains a challenge. Here, we demonstrate a rationally designed system that synergistically combines radiative shielding and cooling—dissipating the latent heat of condensation radiatively to outer space—with a fully passive superhydrophobic condensate harvester, working with a coalescence-induced water removal mechanism. A rationally designed shield, accounting for the atmospheric radiative heat, facilitates daytime atmospheric water harvesting under solar irradiation at realistic levels of relative humidity. The remarkable cooling power enhancement enables dew mass fluxes up to 50 g m−2 hour−1, close to the ultimate capabilities of such systems. Our results demonstrate that the yield of related technologies can be at least doubled, while cooling and collection remain passive, thereby substantially advancing the state of the art.

scholarly journals A Waste Heat-Driven Cooling System Based on Combined Organic Rankine and Vapour Compression Refrigeration Cycles

2019 ◽  
Vol 9 (20) ◽  
pp. 4242 ◽  
Author(s):  
Youcai Liang ◽  
Zhibin Yu ◽  
Wenguang Li
Keyword(s):  
Power Plant ◽  
Internal Combustion Engines ◽  
Waste Heat ◽  
Cooling System ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Compression Cycle ◽  
Vapour Compression

In this paper, a heat driven cooling system that essentially integrated an organic Rankine cycle power plant with a vapour compression cycle refrigerator was investigated, aiming to provide an alternative to absorption refrigeration systems. The organic Rankine cycle (ORC) subsystem recovered energy from the exhaust gases of internal combustion engines to produce mechanical power. Through a transmission unit, the produced mechanical power was directly used to drive the compressor of the vapour compression cycle system to produce a refrigeration effect. Unlike the bulky vapour absorption cooling system, both the ORC power plant and vapour compression refrigerator could be scaled down to a few kilowatts, opening the possibility for developing a small-scale waste heat-driven cooling system that can be widely applied for waste heat recovery from large internal combustion engines of refrigerated ships, lorries, and trains. In this paper, a model was firstly established to simulate the proposed concept, on the basis of which it was optimized to identify the optimum operation condition. The results showed that the proposed concept is very promising for the development of heat-driven cooling systems for recovering waste heat from internal combustion engines’ exhaust gas.

Modeling and Design of Micro-Grooved Flat Plate Evaporator

2005 ◽  
Author(s):  
Naoki Shikazono ◽  
Yasushi Suehisa ◽  
Nobuhide Kasagi ◽  
Hiroshi Iwata
Keyword(s):  
Heat Transfer ◽  
Pressure Gradient ◽  
Flat Plate ◽  
Void Fraction ◽  
Local Heat ◽  
Curvature Radius ◽  
Test Model ◽  
Vapor Compression ◽  
Compression Cycle ◽  
Region Model

A micro-grooved flat plate evaporator is modeled and its heat transfer characteristics are investigated numerically and experimentally. A test model is developed for the vapor compression cycle evaporator, where pressure gradient drives the vapor and the liquid flow. In this study, the effect of pressure gradient is implicitly introduced through the Smith’s equation for predicting void fraction from given quality. The film thickness profile in the micro region near the contact line is obtained by solving the 4th order differential equation. Then the local heat flux is obtained by assuming that the heat conduction through the liquid is one dimensional in the wall normal direction. The shape of liquid-vapor interface is assumed to be a circular arc in the macro region, whose radius is directly linked to the void fraction. This curvature radius is used as the boundary condition for the micro region model at the micro-macro interface. Finally, the heat transfer coefficient on a micro-grooved flat plate evaporator is measured in a HFC134a experimental loop and compared with the numerical prediction. The present model assumptions are validated and assessed.

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