Comparison of a Thermoacoustic Refrigerator Stack Performance: Mylar Spiral, Celcor Substrates and 3D Printed Stacks

2019 ◽  
Vol 27 (03) ◽  
pp. 1950021
Author(s):  
N. A. Zolpakar ◽  
N. Mohd-Ghazali
Keyword(s):  
Optimal Design ◽  
Temperature Difference ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Optimized Design ◽  
Multi Objective Genetic Algorithm ◽  
Potential Alternative ◽  
3D Printed ◽  
Thermoacoustic Refrigeration

Although the thermoacoustic refrigeration (TAR) system has been recognized as a potential alternative environmentally cooling system, the low coefficient of performance (COP) has yet to make it marketable. One major factor contributing towards the low COP is the fabrication method applied to the stack component which is the most important component in the TAR. In this paper, comparison of the performance of a (i) 3D printed stack, (ii) a hand fabricated Mylar stack and (iii) an off-the-shelf Celcor substrates stack has been done; these being based on optimized design parameters using Multi-Objective Genetic Algorithm (MOGA). The performance is determined from the temperature attained at the cold end of the stack and the temperature difference across the stack. Experimental results showed that the 3D printed stack has the best performance by achieving a temperature, [Formula: see text]C at the cold end and a temperature difference of [Formula: see text]C across the stack, about 60% of the designed temperature difference even though the fabricated 3D printed stack deviated from the optimal design due to fabrication constraint as compared to that of the Mylar stack which was closer to the optimal design. This 3D printing of the stack promises a big potential in the improvement of the TAR performance because of the consistency achievable with the precise dimensions of the stack.

Numerical Analysis of Optimal Design Parameters for a Cell Co-Culture Microfluidic Platform With an Integrated Pressure-Controlled Valve

2020 ◽  
Author(s):  
Saif Mohammad Ishraq Bari ◽  
Louis G. Reis ◽  
Thomas Holland ◽  
Gergana G. Nestorova
Keyword(s):  
Numerical Analysis ◽  
Optimal Design ◽  
Vertical Direction ◽  
Design Parameters ◽  
Adjacent Cell ◽  
Membrane Thickness ◽  
A Cell ◽  
3D Printed ◽  
The Individual ◽  
Pressure Controlled

Abstract This study reports the design, fabrication, and a two-dimensional numerical analysis to identify the optimal operating parameters of a novel microfluidic co-culture platform with an integrated pressure-controlled valve. Replica molding using 3D printed PDMS molds were used for the fabrication of the individual components of the device. Alternation of the position of the PDMS hydraulic valve permits individual manipulation of the cellular microenvironment of the two adjacent cell culture chambers (27.5 mm × 35 mm × 10 mm). The mathematical model analyzes the deflection profile of the valve in the vertical direction as a function of several parameters: valve thicknesses, the pressure exerted by the fluid inside the pressure chamber, and PDMS elasticity determined by the ratio of the elastomer base and the curing reagent. The valve understudy requires a deflection of 0.5 mm to completely isolate the two cell chambers. The combination of the optimal design parameters is identified using numerical analysis. Mathematical simulations show that the deflection of the membrane is inversely proportional to the valve membrane thickness and directly proportional to the pressure exerted by the fluid on the valve.

Cooling and heating rate limits of a reversed reciprocating ericsson cycle at steady state

2000 ◽  
Vol 214 (1) ◽  
pp. 75-85 ◽  
Author(s):  
D A Blank ◽  
C Wu
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pump ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Optimized Design ◽  
Cooling Mode ◽  
Working Fluids ◽  
Heating And Cooling

The optimal cooling and heating rates for the reversed reciprocating Ericsson cycle with ideal regeneration are determined for heat pump operations. These limiting rates are based on the upper and lower thermal reservoir temperature bounds and are obtained using time and entropy minimization procedures from irreversible thermodynamics. Use is made of time symmetry (a second law constraint) to minimize cycle time. This optimally allocates the thermal capacitances of the cycle and minimizes internal cycle entropy generation. Although primarily a theoretical work, a very practical and extensive parametric study using several environmentally friendly working fluids (neon, nitrogen and helium) is included. This study evaluates the relative contributions of various system parameters to rate-optimized design. The coefficient of performance (COP), and thus the quantity of cooling or heating for a given energy input, is the traditional focus; instead this work aims at the rate of cooling or heating in heat pumps under steady state conditions and using ideal gases as their working substances. The results obtained provide additional criteria for use in the study, design and performance evaluation of employing Ericsson cycles in refrigeration, air conditioning and heat pump applications. They give direct insight into what is required in designing a reversed Ericsson heat pump to achieve maximum heating and cooling rates. The choices of working fluids and pressure ratios were found to be very significant design parameters, together with selection of regenerator and source—sink heat transfer parameters. The parameter most influencing both the heating and cooling mode COPs and the heat transfer rates was found to be the heat conductance of the thermal sink.

SIMULTANEOUS OPTIMIZATION OF FOUR PARAMETERS IN THE STACK UNIT OF A THERMOACOUSTIC REFRIGERATOR

2014 ◽  
Vol 22 (02) ◽  
pp. 1450011 ◽  
Author(s):  
NOR ATIQAH ZOLPAKAR ◽  
NORMAH MOHD-GHAZALI ◽  
ROBIAH AHMAD
Keyword(s):  
Cooling System ◽  
Acoustic Power ◽  
Optimization Techniques ◽  
Simultaneous Optimization ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Multi Objective Genetic Algorithm ◽  
Parametric Studies ◽  
Discrete Values ◽  
Thermoacoustic Refrigerator

Thermoacoustic refrigerators are environmentally friendly cooling systems that use no refrigerants. Optimization of the performance of any cooling system is crucial for an efficient energy management. Most of the optimization techniques in thermoacoustic systems utilized to date involved experimental and numerical parametric studies which are generally limited to the variations of the parameters to be optimized at discrete values. This study reports on the optimization of a thermoacoustic refrigerator using multi-objective genetic algorithm (MOGA). The study introduces the ability of MOGA to optimize four different variables which are length of stack, center position of stack, blockage ratio and drive ratio simultaneously. The four variables are optimized to achieve the two objectives; a maximum cooling and minimum acoustic power required at the stack and provide the optimum coefficient of performance, COP. The results show that the optimum COP = 1.35 with a cooling power of Qc = 6.57 W, acoustic power of Wn = 4.86 W and with the resonator diameter of D = 3.8 cm.

scholarly journals The processes of vaporization in the porous structures working with the excess of liquid

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 363-373 ◽  
Author(s):  
Alexander Genbach ◽  
Nellya Jamankulova ◽  
Vukman Bakic
Keyword(s):  
Temperature Difference ◽  
High Speed ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Power ◽  
Laser System ◽  
Operating Conditions ◽  
Design Parameters ◽  
Porous Structures ◽  
The Impact

The processes of vaporization in porous structures, working with the excess of liquid are investigated. With regard to the thermal power plants new porous cooling system is proposed and investigated, in which the supply of coolant is conducted by the combined action of gravity and capillary forces. The cooling surface is made of stainless steel, brass, copper, bronze, nickel, alundum and glass, with wall thickness of (0.05-2)?10-3 m. Visualizations of the processes of vaporization were carried out using holographic interferometry with the laser system and high speed camera. The operating conditions of the experiments were: water pressures (0.01-10) MPa, the temperature difference of sub-cooling (0-20)?C, an excess of liquid (1-14) of the steam flow, the heat load (1-60)?104 W/m2, the temperature difference (1-60)?C and orientation of the system (? 0 - ? 90) degrees. Studies have revealed three areas of liquid vaporization process (transitional, developed and crisis). The impact of operating and design parameters on the integrated and thermal hydraulic characteristics was defined. The optimum (minimum) flow rate of cooling fluid and the most effective type of mesh porous structure were also defined.

Justification of design parameters of the fractional reaping conveyor and its devices for removal of beveled stems from under the wheels of the vehicle

2019 ◽  
Vol 1 (3) ◽  
pp. 1-10
Author(s):  
Mikhail M. Konstantinov ◽  
Ivan N. Glushkov ◽  
Sergey S. Pashinin ◽  
Igor I. Ognev ◽  
Tatyana V. Bedych
Keyword(s):  
Optimal Design ◽  
Technological Process ◽  
Design Parameters ◽  
Theoretical Studies ◽  
Optimal Parameters ◽  
Belt Conveyor ◽  
Grain Crops ◽  
Mode Of Operation ◽  
Optimal Values ◽  
Main Component

In this paper we consider the structural and technological process of the combine used in the process of separate harvesting of grain crops, as well as a number of its parameters. Among the main units of the combine, we allocate a conveyor and devices for removing beveled stems from under the wheels of the vehicle. The principle of operation of the conveyor at different phases of the Reaper and especially the removal of cut stems from under the wheels of the vehicle during operation of the Reaper. The results of theoretical studies on the establishment of the optimal design of the parameters of the belt conveyor are presented, the ranges of their optimal values are considered and determined. Studies on the establishment of optimal parameters of the screw divider in the Reaper, which is the main component of the device for removal of beveled stems, are presented. Taking into account the optimal design and mode of operation of the screw divider, the correct work is provided to remove the cut stems from under the wheels of the harvester.

scholarly journals A Novel Approach for a Faster Prototyping of Winter Sport Equipment Using Digital Image Correlation and 3D Printing

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 125
Author(s):  
Martino Colonna ◽  
Benno Zingerle ◽  
Maria Federica Parisi ◽  
Claudio Gioia ◽  
Alessandro Speranzoni ◽  
...  
Keyword(s):  
3D Printing ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Sport Activity ◽  
Image Correlation ◽  
Topological Optimization ◽  
Design Parameters ◽  
Sport Equipment ◽  
Novel Approach ◽  
3D Printed

The optimization of sport equipment parts requires considerable time and high costs due to the high complexity of the development process. For this reason, we have developed a novel approach to decrease the cost and time for the optimization of the design, which consists of producing a first prototype by 3D printing, applying the forces that normally acts during the sport activity using a test bench, and then measuring the local deformations using 3D digital image correlation (DIC). The design parameters are then modified by topological optimization and then DIC is performed again on the new 3D-printed modified part. The DIC analysis of 3D-printed parts has shown a good agreement with that of the injection-molded ones. The deformation measured with DIC are also well correlated with those provided by finite element method (FEM) analysis, and therefore DIC analysis proves to be a powerful tool to validate FEM models.

scholarly journals Optimal Design Parameters for a Phased Array Based Ultrasonic Polar Scan

2021 ◽  
pp. 1-1
Author(s):  
Jannes Daemen ◽  
Arvid Martens ◽  
Mathias Kersemans ◽  
Erik Verboven ◽  
Steven Delrue ◽  
...  
Keyword(s):  
Optimal Design ◽  
Phased Array ◽  
Design Parameters ◽  
Ultrasonic Polar Scan

scholarly journals Performance Analysis of Hybrid Desiccant Cooling System with Enhanced Dehumidification Capability Using TRNSYS

2021 ◽  
Vol 11 (7) ◽  
pp. 3236
Author(s):  
Ji Hyeok Kim ◽  
Joon Ahn
Keyword(s):  
Thermal Comfort ◽  
Cooling System ◽  
Operation Mode ◽  
Heat Removal ◽  
Simulation Models ◽  
Coefficient Of Performance ◽  
Dimensional Structure ◽  
Dominant Factor ◽  
Exhaust Heat ◽  
Chp System

In a field test of a hybrid desiccant cooling system (HDCS) linked to a gas engine cogeneration system (the latter system is hereafter referred to as the combined heat and power (CHP) system), in the cooling operation mode, the exhaust heat remained and the latent heat removal was insufficient. In this study, the performance of an HDCS was simulated at a humidity ratio of 10 g/kg in conditioned spaces and for an increasing dehumidification capacity of the desiccant rotor. Simulation models of the HDCS linked to the CHP system were based on a transient system simulation tool (TRNSYS). Furthermore, TRNBuild (the TRNSYS Building Model) was used to simulate the three-dimensional structure of cooling spaces and solar lighting conditions. According to the simulation results, when the desiccant capacity increased, the thermal comfort conditions in all three conditioned spaces were sufficiently good. The higher the ambient temperature, the higher the evaporative cooling performance was. The variation in the regeneration heat with the outdoor conditions was the most dominant factor that determined the coefficient of performance (COP). Therefore, the COP was higher under high temperature and dry conditions, resulting in less regeneration heat being required. According to the prediction results, when the dehumidification capacity is sufficiently increased for using more exhaust heat, the overall efficiency of the CHP can be increased while ensuring suitable thermal comfort conditions in the cooling space.

scholarly journals 3D-printed gelatin methacrylate (GelMA)/silanated silica scaffold assisted by two-stage cooling system for hard tissue regeneration

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Eunjeong Choi ◽  
Dongyun Kim ◽  
Donggu Kang ◽  
Gi Hoon Yang ◽  
Bongsu Jung ◽  
...  
Keyword(s):  
Osteogenic Differentiation ◽  
Tissue Regeneration ◽  
Cooling System ◽  
Composite Scaffold ◽  
Human Mesenchymal Stem Cells ◽  
Temperature Control System ◽  
Process Conditions ◽  
Hard Tissue ◽  
Two Stage ◽  
3D Printed

Abstract Among many biomaterials, gelatin methacrylate (GelMA), a photocurable protein, has been widely used in 3D bioprinting process owing to its excellent cellular responses, biocompatibility and biodegradability. However, GelMA still shows a low processability due to the severe temperature dependence of viscosity. To overcome this obstacle, we propose a two-stage temperature control system to effectively control the viscosity of GelMA. To optimize the process conditions, we evaluated the temperature of the cooling system (jacket and stage). Using the established system, three GelMA scaffolds were fabricated in which different concentrations (0, 3 and 10 wt%) of silanated silica particles were embedded. To evaluate the performances of the prepared scaffolds suitable for hard tissue regeneration, we analyzed the physical (viscoelasticity, surface roughness, compressive modulus and wettability) and biological (human mesenchymal stem cells growth, western blotting and osteogenic differentiation) properties. Consequently, the composite scaffold with greater silica contents (10 wt%) showed enhanced physical and biological performances including mechanical strength, cell initial attachment, cell proliferation and osteogenic differentiation compared with those of the controls. Our results indicate that the GelMA/silanated silica composite scaffold can be potentially used for hard tissue regeneration.

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