Lexicographic multi-objective optimization of thermoacoustic refrigerator’s stack
- Tartibu, L.K., Sun, B., Kaunda, M.A.E.
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Thermoacoustic , Stack , Cooling Load , Coefficient of performance , Multi-objective optimization , GAMS
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17624 , uj:15907 , ISSN: 0947-7411 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Lexicographic multi-objective optimisation of thermoacoustic refrigerator’s stack. Journal of Heat and Mass Transfer. 51(5): 649-660. DOI: 10.1007/s00231-014-1440-z. , DOI: 10.1007/s00231-014-1440-z
- Description: Abstract: This work develops a novel mathematical programming model to optimize the performance of a simple thermoacoustic refrigerator (TAR). This study aims to optimize the geometric parameters namely the stack position, the stack length, the blockage ratio and the plate spacing involved in designing TARs. System parameters and constraints that capture the underlying thermoacoustic dynamics have been used to define the models. The cooling load, the coefficient of performance and the acoustic power loss have been used to measure the performance of the device. The optimization task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives (DNLP). Since we optimize multiple objectives simultaneously, each objective component has been given a weighting factor to provide appropriate user-defined emphasis. A practical example is given to illustrate the approach. We have determined a design statement of a stack describing how the geometrical parameters describing would change if emphasis is given to one objective in particular. We also considered optimization of multiple objectives components simultaneously and identify global optimal solutions describing the stack geometry using a lexicographic multiobjective optimization scheme. Additionally, this approach illustrates the difference between a design for maximum cooling and best coefficient of performance of a simple TAR.
- Full Text:
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Thermoacoustic , Stack , Cooling Load , Coefficient of performance , Multi-objective optimization , GAMS
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17624 , uj:15907 , ISSN: 0947-7411 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Lexicographic multi-objective optimisation of thermoacoustic refrigerator’s stack. Journal of Heat and Mass Transfer. 51(5): 649-660. DOI: 10.1007/s00231-014-1440-z. , DOI: 10.1007/s00231-014-1440-z
- Description: Abstract: This work develops a novel mathematical programming model to optimize the performance of a simple thermoacoustic refrigerator (TAR). This study aims to optimize the geometric parameters namely the stack position, the stack length, the blockage ratio and the plate spacing involved in designing TARs. System parameters and constraints that capture the underlying thermoacoustic dynamics have been used to define the models. The cooling load, the coefficient of performance and the acoustic power loss have been used to measure the performance of the device. The optimization task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives (DNLP). Since we optimize multiple objectives simultaneously, each objective component has been given a weighting factor to provide appropriate user-defined emphasis. A practical example is given to illustrate the approach. We have determined a design statement of a stack describing how the geometrical parameters describing would change if emphasis is given to one objective in particular. We also considered optimization of multiple objectives components simultaneously and identify global optimal solutions describing the stack geometry using a lexicographic multiobjective optimization scheme. Additionally, this approach illustrates the difference between a design for maximum cooling and best coefficient of performance of a simple TAR.
- Full Text:
Experimental investigation of an adjustable thermoacoustically-driven thermoacoustic refrigerator
- Alcock, A. C., Tartibu, L. K., Jen, T. C.
- Authors: Alcock, A. C. , Tartibu, L. K. , Jen, T. C.
- Date: 2018
- Subjects: Thermoacoustic , Refrigeration , TADTAR
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/281227 , uj:30258 , Citation: Alcock, A.C., Tartibu, L.K. & Jen, T.C. 2018. Experimental investigation of an adjustable thermoacoustically-driven thermoacoustic refrigerator.
- Description: Abstract: An experimental investigation is conducted on a new adjustable thermoacoustically-driven thermoacoustic refrigerator (TADTAR). This refrigerator comprises of a thermoacoustic engine which drives a thermoacoustic refrigerator. This study aims to demonstrate the possibility to alter the TADTAR performance through the adjustment of specific design parameters. An adjustable resonator, which consisted of stacks, spacing couplings and shell-tube heat exchangers was designed and built. Six different honeycomb ceramic stacks were investigated. For each system, three different stack configuration were studied. Measurements of temperature difference across the refrigerator stack and sound pressure levels at steady states were used to determine the performance of the device. Through the adjustment of the length and the insertion of the heat exchanger, the performance of the device with a longer resonator was relatively higher. This study shows that an adjustable resonator successfully alters the frequency output of the thermoacoustic engine to match the frequency required by the thermoacoustic refrigerator and achieve resonance. In addition, this study demonstrates the possibility to change the geometrical configuration of the device and ultimately alter the performance of the TADTAR. Through the adjustment of the length of the resonator, this study shows that a single device could have different operating points. This creates new possibilities to introduce control system able to adjust the geometry of thermoacoustic system while in operation.
- Full Text:
- Authors: Alcock, A. C. , Tartibu, L. K. , Jen, T. C.
- Date: 2018
- Subjects: Thermoacoustic , Refrigeration , TADTAR
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/281227 , uj:30258 , Citation: Alcock, A.C., Tartibu, L.K. & Jen, T.C. 2018. Experimental investigation of an adjustable thermoacoustically-driven thermoacoustic refrigerator.
- Description: Abstract: An experimental investigation is conducted on a new adjustable thermoacoustically-driven thermoacoustic refrigerator (TADTAR). This refrigerator comprises of a thermoacoustic engine which drives a thermoacoustic refrigerator. This study aims to demonstrate the possibility to alter the TADTAR performance through the adjustment of specific design parameters. An adjustable resonator, which consisted of stacks, spacing couplings and shell-tube heat exchangers was designed and built. Six different honeycomb ceramic stacks were investigated. For each system, three different stack configuration were studied. Measurements of temperature difference across the refrigerator stack and sound pressure levels at steady states were used to determine the performance of the device. Through the adjustment of the length and the insertion of the heat exchanger, the performance of the device with a longer resonator was relatively higher. This study shows that an adjustable resonator successfully alters the frequency output of the thermoacoustic engine to match the frequency required by the thermoacoustic refrigerator and achieve resonance. In addition, this study demonstrates the possibility to change the geometrical configuration of the device and ultimately alter the performance of the TADTAR. Through the adjustment of the length of the resonator, this study shows that a single device could have different operating points. This creates new possibilities to introduce control system able to adjust the geometry of thermoacoustic system while in operation.
- Full Text:
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