Effect of Stack Spacing on the Performance of Thermoacoustic Refrigerators Using Helium and Air as Working Substances

2019 ◽  
Vol 27 (02) ◽  
pp. 1950016 ◽  
Author(s):  
B. G. Prashantha ◽  
S. Seetharamu ◽  
G. S. V. L. Narasimham ◽  
M. R. Praveen Kumar
Keyword(s):  
Heat Exchanger ◽  
Penetration Depth ◽  
Power Density ◽  
Cooling Power ◽  
Quarter Wavelength ◽  
Thermal Penetration Depth ◽  
Theoretical Results ◽  
Theoretical Performance ◽  
Thermoacoustic Refrigerators

This paper deals with the design of thermoacoustic refrigerators using linear thermoacoustic theory. The refrigerator components are designed at 3% drive ratio by considering the practical limitations of providing sufficient spacing for attaching the loudspeaker to the resonator tube and accommodating instrumentation. The effects of spiral stack spacing in terms of thermal penetration depth on the theoretical performance of refrigerator using helium and air as working substances are discussed. The quarter-wavelength resonator designs with taper and divergent section terminated with hemispherical end are optimized with helium and air for better performance. Theoretical results are validated with DeltaEC software results and are in agreement with each other. Helium shows better performance compared to air but lacks power density. The DeltaEC predicts COP 0.514 at the cold heat exchanger temperature of [Formula: see text]C with helium compared to air (COP 0.616 at [Formula: see text]C) for the 50[Formula: see text]W cooling power 100[Formula: see text]mm diameter quarter-wavelength resonator designs.

DESIGN AND ANALYSIS OF THERMOACOUSTIC REFRIGERATOR

2013 ◽  
Vol 21 (01) ◽  
pp. 1350001 ◽  
Author(s):  
B. G. PRASHANTHA ◽  
M. S. GOVINDE GOWDA ◽  
S. SEETHARAMU ◽  
G. S. V. L. NARASIMHAM
Keyword(s):  
Boundary Layer ◽  
Power Density ◽  
Gas Pressure ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Boundary Layer Approximation ◽  
Resonator Design ◽  
Quarter Wavelength ◽  
Calculation Results ◽  
Thermoacoustic Refrigerator

This paper deals with the design and analysis of a quarter-wavelength, 10 W capacity, thermoacoustic refrigerator using short stack boundary layer approximation assumptions. The effect of operating frequency on the performance of the refrigerator is studied using dimensional normalization technique. The variation of stack diameter with average gas pressure and cooling power is discussed. The resonator optimization is discussed and the calculation results show a 9% improvement in the coefficient of performance and 201% improvement in power density for the optimized quarter-wavelength resonator compared to published optimization studies. The optimized resonator design is tested with DeltaEC software and the results show better performance compared to past established resonator designs.

Design Optimization and Analysis of Thermoacoustic Refrigerators

2020 ◽  
Vol 28 (03) ◽  
pp. 2050020
Author(s):  
B. G. Prashantha ◽  
D. R. Swamy ◽  
Bhimasen Soragaon ◽  
T. S. Nanjundeswaraswamy
Keyword(s):  
Design Optimization ◽  
Noble Gases ◽  
Cooling Power ◽  
Dry Air ◽  
Novel Technology ◽  
Pure Helium ◽  
Simulation Results ◽  
Thermoacoustic Refrigeration ◽  
Theoretical Results ◽  
Thermoacoustic Refrigerators

Thermoacoustic refrigeration, a novel technology, uses eco-friendly gases like helium, air or the mixture of noble gases as working substances in the absence of moving parts. The design, optimization and analysis of thermoacoustic refrigerators using helium and air as oscillating gases are discussed. Pure helium is chosen since it is proven as the best and economical working gas compared to the alternate pure or the mixture of noble gases. Air is chosen since it is abundant in nature and the least cost of the pressurized dry air cylinders. The design optimization strategies discussed in this paper serve as a guide for aspiring researchers in the design and development of thermoacoustic coolers. Cooling power as a function of stack diameter is discussed. Theoretical results of the optimized coolers are compared with DeltaEC simulation results for validation and are in agreement with each other.

Design Construction and Performance of 10W Thermoacoustic Refrigerators

2017 ◽  
Vol 25 (03) ◽  
pp. 1750023 ◽  
Author(s):  
B. G. Prashantha ◽  
M. S. Govinde Gowda ◽  
S. Seetharamu ◽  
G. S. V. L. Narasimham
Keyword(s):  
Comparative Analysis ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Small Diameter ◽  
Cooling Power ◽  
Experimental Measurements ◽  
And Performance ◽  
Assembly Procedure ◽  
Design Construction ◽  
Thermoacoustic Refrigerators

In this paper, the construction and performance of the 10[Formula: see text]W cooling power thermoacoustic refrigerators designed for a temperature difference of 120 K at 3% drive ratio are discussed. The construction and assembly procedure of the optimized thermoacoustic refrigerator components viz. spiral stack, heat exchangers, 0.28[Formula: see text]-taper, small diameter tube and divergent section with hemispherical end (TSDH) and 0.24[Formula: see text]-taper and divergent section with hemispherical end (TDH) resonator designs and loudspeaker found in the published literature, and instrumentation are discussed. The performance of the 0.28[Formula: see text]-TSDH, and 0.24[Formula: see text]-TDH resonator designs, and the uncertainties involved in the experimental measurements are discussed. Both the resonator designs show good behavior. A decent low temperature of [Formula: see text]11.3[Formula: see text]C and [Formula: see text]8.7[Formula: see text]C at 10[Formula: see text]W cooling power is achieved at the cold heat exchanger for the 0.28[Formula: see text]-TSDH and 0.24[Formula: see text]-TDH resonator designs, respectively. The comparative analysis of the experimental results with the theoretical and DeltaEC results is discussed.

High cooling power density SiGe/Si micro-coolers

2001 ◽  
Vol 37 (2) ◽  
pp. 126 ◽  
Author(s):  
X. Fan ◽  
G. Zeng ◽  
E. Croke ◽  
C. LaBounty ◽  
C.C. Ahn ◽  
...  
Keyword(s):  
Power Density ◽  
Cooling Power

Cooling power characteristics of half-cycle refrigeration system in LPG fuelled vehicles by auxiliary chiller as heat exchanger

2021 ◽  
pp. 101145
Author(s):  
Muji Setiyo ◽  
Bagiyo Condro Purnomo ◽  
Budi Waluyo ◽  
Suroto Munahar ◽  
Muhammad Latifur Rochman ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Cooling Power ◽  
Half Cycle ◽  
Refrigeration System ◽  
Power Characteristics

Resonator Optimization and Studying the Effect of Drive Ratio on the Theoretical Performance of a 10-W Cooling Power Thermoacoustic Refrigerator

2015 ◽  
Vol 23 (03) ◽  
pp. 1550020 ◽  
Author(s):  
B. G. Prashantha ◽  
M. S. Govinde Gowda ◽  
S. Seetharamu ◽  
G. S. V. L. Narasimham
Keyword(s):  
Dynamic Pressure ◽  
Optimization Procedure ◽  
Cooling Power ◽  
Pressure Amplitude ◽  
Performance Simulation ◽  
Resonator Design ◽  
Working Principle ◽  
Simulation Results ◽  
Theoretical Performance ◽  
Thermoacoustic Refrigerator

This paper deals with the basic insight of thermoacoustic refrigeration concepts, and the working principle, history and the role of linear thermoacoustic theory in designing a thermoacoustic refrigerator system are discussed. Resonator design optimization procedure for a 10W cooling power thermoacoustic refrigerators is discussed. The optimized resonator designs proposed in this paper are found to be efficient compared to published resonator designs. The effects of drive ratio on the theoretical performance by varying dynamic pressure amplitude from 0.2 bar to 0.4 bar in the steps of 0.05 bar on the optimized resonator designs are discussed. Performance simulation results for the optimized resonator designs using DeltaEC software are discussed. Simulation results are in agreement with theoretical results.

scholarly journals Theoretical Performance Evaluation of a Marine Solid Propellant Water-Breathing Ramjet Propulsor

2019 ◽  
Vol 8 (1) ◽  
pp. 8 ◽  
Author(s):  
Nachum E. Eisen ◽  
Alon Gany
Keyword(s):  
Performance Evaluation ◽  
Ammonium Perchlorate ◽  
Solid Propellant ◽  
Specific Impulse ◽  
Marine Water ◽  
Metal Particles ◽  
Conceptual Scheme ◽  
Thrust Coefficient ◽  
Theoretical Results ◽  
Theoretical Performance

This work analyzes and presents theoretical performance of a marine water-breathing ramjet propulsor. A conceptual scheme of the motor is shown, the equation of thrust is presented, and the dependence on cruise velocity and depth are discussed. Different propellant compositions, representing a wide variety of formulations suitable for propelling a water-breathing ramjet, are investigated. The theoretical results reveal that the specific impulse of a water-breathing ramjet can increase by as much as 30% compared to a standard rocket, when using a conventional hydroxyl terminated polybutadiene (HTPB)-ammonium perchlorate (AP) propellant, which does not react chemically with the water. When employing a water-reactive propellant containing metal particles such as magnesium or aluminum, the specific impulse may be more than doubled. The thrust coefficient of the propulsor was computed at different cruise velocities and depths and was found to be greater than the predictable drag even at significant depth.

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