Optimised design of the standing-wave thermoacoustic refrigerator with lagrange multiplier method
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Date
2015
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Publisher
Universiti Teknologi Malaysia
Abstract
Thermoacoustic refrigeration is a promising environmentally friendly technology for the sustainable life of our future. Practical applications of standing wave thermoacoustic refrigerators are limited by their low performance compared to their counterpart, the conventional vapor compression refrigerators. A systematic and comprehensive design framework of an optimized standing wave thermoacoustic refrigerator is set up to address this issue and provide a base for future research and applications. A numerical optimization procedure based on the Lagrange multiplier method has been developed to simultaneously optimize the stack length and center position within a standard standing wave thermoacoustic refrigerator. The stack is the heart of the thermoacoustic system where the thermoacoustic effects are highly desirable; its optimization subsequently determines the other parts of the refrigerator. A MATLAB software program was used to solve the system of equations and implement the optimization procedure. The effects of four parameters under optimized conditions were investigated; the mean design temperature, temperature difference, drive ratio and mean pressure. The performance of the stack was validated against a completed past experimental and numerical works. It showed a possible 10 to 32 percent higher in performance. Furthermore, the performance of the entire refrigerator was compared against the outputs from DeltaEC, which is a thermoacoustic software, to evaluate the reliability of the developed optimization procedure. The current procedure showed a potential increase of the performance by 70 percent. This systematic and comprehensive optimized design procedure provides a framework for future design and development of a standing wave thermoacoustic refrigerator.
Description
Thesis (PhD. (Mechanical Engineering)
Keywords
Refrigerators, Standing waves, Refrigeration and refrigerating machinery—Design and construction