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Design and Control of a Standing-Wave Thermoacoustic Refrigerator

Ryan, Timothy S (2010) Design and Control of a Standing-Wave Thermoacoustic Refrigerator. Master's Thesis, University of Pittsburgh. (Unpublished)

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A thermoacoustic refrigerator was designed using a dimensionless parameter approach. Some basic insight into thermoacoustic design principles was obtained. The resulting device was used as a test bed for three different control schemes. The first was a phase-locked loop, which is the control method most often used in the literature; the second controller utilized a gradient ascent algorithm to track the operating frequency of maximum acoustic pressure; and the third utilized the same gradient ascent architecture to track the operating frequency corresponding to maximum acoustic power transfer to the resonator. The three controllers, tracking different parameters associated with a strong thermoacoustic effect, were compared in simulations and experiments. Difficulties in collecting data for the power controller resulted in unreliable data. Therefore, the power controller was not compared quantitatively with the other two. The PLL performed best in terms of thermoacoustic efficiency, but the acoustic pressure controller was able to produce more cooling power and converted electrical power to cooling power more efficiently due to the amplitude of the input voltage to the driver being held constant. The major short-coming of the gradient ascent approach was the relatively long convergence time. However, convergence time is not always relevant to refrigerator operation. The maximum acoustic pressure control scheme was determined to be the best controller considered because it has fewer sensors than the other two controllers, involves less computational effort than the power controller, and yielded better electrothermal performance than the PLL.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Ryan, Timothy Stsr2@pitt.eduTSR2
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairVipperman, Jeffreyjsv@pitt.eduJSV
Committee MemberSchaefer, Lauralas149@pitt.eduLAS149
Committee MemberClark, Williamwclark@pitt.eduWCLARK
Date: 26 January 2010
Date Type: Completion
Defense Date: 30 November 2009
Approval Date: 26 January 2010
Submission Date: 13 November 2009
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering
Degree: MSME - Master of Science in Mechanical Engineering
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: gradient descent algorithm; extremum-seeking control; TAR
Other ID:, etd-11132009-152225
Date Deposited: 10 Nov 2011 20:04
Last Modified: 15 Nov 2016 13:51


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