Dr. Liaqat Ali Khan

214 Pages·2013·15.3 MB·English

by  Liaquat Ali Khan

EXERGETIC THERMOECONOMIC
HEAT EXCHANGER OPTIMIZATION MODEL

Liaquat Ali Khan

05-UET/PhD-ME-18

Department of Mechanical Engineering
Faculty of Mechanical & Aeronautical Engineering
University of Engineering &Technology
Taxila-Pakistan
July 2013
EXERGETIC THERMOECONOMIC
HEAT EXCHANGER OPTIMIZATION MODEL

Liaquat Ali Khan

05-UET/PhD-ME-18

Department of Mechanical and Aeronautical Engineering

Faculty of Mechanical & Aeronautical Engineering

University of Engineering and Technology
Taxila-Pakistan

July 2013
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EXERGETIC THERMOECONOMIC
HEAT EXCHANGER OPTIMIZATION MODEL

Author

Liaquat Ali Khan

05-UET/PhD-ME-18

A thesis submitted in partial fulfillment of the requirement for the
degree of

PhD Mechanical Engineering

Thesis Supervisor

Asst. Prof. Dr. Muhammad Shehryar

Thesis Supervisor‟s Signatures
________________________

_____________________________ ______________________________
External Examiner‟s Signatures External Examiner‟s Signatures
Prof. Dr. Bsharat Ullah Malik Prof. Dr. Abdul Ghafoor

Department of Mechanical Engineering

Faculty of Mechanical & Aeronautical Engineering

University of Engineering and Technology, Taxila, Pakistan

July 2013
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Supervisor

Asst. Prof. Dr. Muhammad Shehryar

Members of Research Monitoring Committee

Prof. Dr. Arshad Hussain Qureshi

Prof. Dr. Zafar Ullah Koreshi

Prof. Dr. Shahab Khushnood

Foreign Research Evaluation Experts

Prof. Dr. Gary Marlin Sandquist, USA

Prof. Dr. Mikhael Gorokhovski, France

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Foreign Expert Evaluation Report

Minor corrections (English grammar) made to abstract for dissemination. Contribution
was of engineering/economic significance for performing thermodynamic analysis and
optimization of heat exchangers using new methods of analysis.

Gary M. Sandquist

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Foreign Expert Evaluation Report

This thesis is focused on the complex problem of cost/design optimization in heat
exchangers. The major contribution of this thesis is two-fold. First, it is the new
application of evolutionary population-based algorithm in the context of optimization of
heat exchangers. Second, it is the economic analysis of improved designs, proposed in
the thesis.

The thesis is comprised of six chapters and six appendices. In the first chapter a
general description of heat exchangers, the basic formulation of zero-dimensional
thermodynamic models, and a general introduction to optimization methods are given. In
the second chapter, the evolutionary algorithm is introduced. On the basis of this
approach, the cost/design sensitivity analysis for shell and tube exchangers is performed
in the third chapter, for different liquids and for different operating parameters. A
considerable amount of results is assessed by comparison with existing approaches in the
literature. Chapter four is devoted to energy recovery optimization in the cross-flow
plate-fin heat exchanger. Here again in coupling with convective heat transfer relations
in the plate-fin exchanger, the Author applied and assessed the evolutionary algorithm in
order to minimize consumptions in the air-conditioning system. The similar strategy is
applied in five‟s chapter for the cross-flow tube-fin heat exchanger. Here also the
emphasis is put on the economic significance of design improvements proposed in the
thesis. The thesis is ended up with conclusion (chapter six)

In summary, the thesis provides a novel application of optimization methods to
heat exchangers. The proposed designs and their economic analysis are straightforward
to be applied in engineering.
I thus give a favorable opinion for the defense of the thesis of Mr. Liaqat Ali Khan.

Mikhael Gorokhovski

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Dedicated

To my family, my sisters

For their devotion and prayers for my success

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Acknowledgement

I am grateful for the opportunity to work with my supervisor , Dr. Muhammad Shehryar,
for the guidance and encouragement conducting this research and the experience gained
from the discussion on the topic. Also, his open, frank discussions concerning
professional approach were enlightening and appreciated.
I am also thankful to Dr. Ali Ghalban and Dr. Fathi Mahfouz for their able
guidance in the early and middle stages of my research. Without their guidance and help
this research will not be possible.
The commitment of the remaining committee members, Dr. Arshad Qureshi, Dr.
Zafar Ullah Koreshi and Dr. Shahab Khushnood also recognized. Their comments and
suggestion were instructive.
The Department of Mechanical and Aerospace Engineering is acknowledged for
the continued generous support. Special thanks to Dr. Muhammad Shahid Khalil for his
continuous guidance in administrative matter of my PhD degree program.
Finally, I would like to thank my family, who has endured through my education
and give love and encouragement. My sisters are appreciated for their endless
unassuming support, without which this point could have never been reached.

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Research Work Publications

1. Liaquat A. Khan, Fathi Mahfouz, Thermoeconomic Lifecycle Cost
Optimization of an Annular Fin Heat Exchanger, Pakistan Journal of
Engineering and Applied Sciences, vol 11, pp 129-140, July 2012.

2. Liaquat A. Khan, Fathi Mahfouz, Thermoeconomic Lifecycle Energy
Recovery System Optimization For Central Air-Conditioning System
Using Evolutionary Technique, Mehran University Research Journal
of Engineering & Technology, Volume 31, No. 1, pp 13-28, January,
2012.

3. Liaquat Ali Khan, Dr. Ali El-Ghalban, Heat Exchanger Exergetic
Lifecycle Cost Optimization using Evolutionary Algorithms,
WSEAS Transaction on Heat and Mass Transfer , Issue 1, Volume 3,,
pp125-136. January 2008

4. Liaquat Ali Khan, Dr. Ali El-Ghalban, Heat Exchanger
Exergoeconomic Lifecycle Cost Optimization, 3rd IASME/WSEAS
Int. Conf. on Energy & Environment, University of Cambridge, UK,
Feburary 23-25, 2008.

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Abstract

An investigation on the life cycle cost and annual cost of heat exchanger using
evolutionary optimization for both shell and tube and compact heat exchangers (plate-fin
heat exchanger and tube-fin heat exchanger) is done in this thesis. Cost includes capital
cost, pumping cost and exergy destruction cost. Pumping and exergy destruction costs are
the components of operating cost. Considering life cycle cost during the design phase of
thermal systems gives the design effort more worth. Optimized thermal parameters,
which give minimum cost, are important targets for both designers and users. The
optimization technique used in this study is evolutionary algorithm. Evolutionary
Optimization technique has recently experienced a remarkable growth [1]. A rapid
solution of the design problem enables to examine number of alternative solutions of
good quality, obtained using Evolutionary algorithms. Evolutionary algorithm gives the
designer more degree of freedom in the final choice compared to the traditional methods.
The code for thermal design of heat exchanger and for evolutionary optimization is
written in MATLAB®.

For shell and tube heat exchanger life cycle cost optimization procedure has been
developed. The objective function is to minimize the total cost, which includes capital
cost and the sum of discounted annual energy expenditures cost related to pumping and
exergy destruction. Effect of inflation on operating cost over the life of heat exchanger is
also considered. A reduction of 11.4% in capital cost and savings in operating cost is up
to 90.8% is obtained, with an overall decrease of life cycle cost up to 46.5%. Hence the
dominant factor in the life cycle cost of heat exchanger is the operating cost [2,3]. The
results obtained with Evolutionary Strategy (ES) is also compared with Genetic
Algorithm (GA), Direct Search (DS) and Simplex Method (SM) which are inbuilt
functions in Engineering Equation Solver (EES®) professional version. The results
obtained using ES are very close to GA and also comparable with DS and SM.
Sensitivity analysis with electricity prices is also performed. Parametric study of annual
cost with different baffle spacing ratios (BSR), Pitch Ratio (PR) and tube arrangement is
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