LOW TEMPERATURE WASTE ENERGY HARVESTING BY SHAPE MEMORY ALLOY ACTUATOR

190 Pages·2016·10.33 MB·English

LOW TEMPERATURE WASTE ENERGY HARVESTING BY SHAPE MEMORY
ALLOY ACTUATOR

A Dissertation
Presented to
The Graduate Faculty of The University of Akron

In Partial Fulfillment
of the Requirements for the Degree
Doctor of Philosophy

Ashenafi B. Hegana
May, 2016
LOW TEMPERATURE WASTE ENERGY HARVESTING BY SHAPE MEMORY
ALLOY ACTUATOR

Ashenafi B. Hegana
Dissertation

Approved: Accepted:

______________________________ ______________________________
Advisor Department Chair
Dr. Erik Engeberg Dr. Sergio Felicelli

______________________________ ______________________________
Acting Advisor Interim Dean of the College
Dr. Celal Batur Dr. Eric Amis

______________________________ ______________________________
Committee Member Dean of the Graduate School
Dr. D. Dane Quinn Dr. Chand Midha

______________________________ ______________________________
Committee Member Date
Dr. Hariharan Subramaniya I

______________________________
Committee Member
Dr. Alper Buldum
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ABSTRACT

Waste heat energy harvesting has been one of the techniques used to reduce
emission of CO and improve efficiency of power generation, oil mining and different
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industrial processes. Nearly 90% of waste heat is considered low-grade (< 230OC) and is
unsuitable for traditional waste heat recovery techniques. Thus, a non-continuous SMA
Energy Harvesting prototype (EHP) to convert low-grade heat into electricity is presented
in this research.
We first demonstrate the feasibility of EHP using non-continuous shape memory
alloy actuators (SMA) to convert waste heat energy to electricity. Both linear and spring
shaped SMA wires made of NiTi alloy have been used to evaluate the energy harvesting
capability of EHP. The experimental results proved that the EHP can generate oscillatory
shaft rotation. The EHP test where the generator was connected to the main shaft through
gear-box provided nearly 10V and 2.5rads shaft rotation in 0.3s. It was also found that the
helical spring SMA actuator energy conversion factor was higher than that of the linear
SMA actuator.
Next, energy storage on both super-capacitors and micro-capacitors by the EHP
with the helical spring SMA wire was explored. Using full-wave rectifier circuit, the
average steady state energy stored across 6F capacitor per 2.5s of operation was 7.4mJ that
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is greater by factors of 4, 2 &1.2 from the stored energy across 1.4mF, 2.2mF & 3.3mF
capacitors, respectively.
The SMA cyclic heating and cooling experiment was developed to evaluate the
relationship between SMA stress and SMA temperature, and to validate the hysteretic
behavior of SMA actuator upon thermal loading. Sigmoidal-Weibull 4 parameter model
was obtained as the best curve fitted model to the experimental SMA stress-temperature
data. The test results also disclosed the hysteretic characteristic of SMA wires induced by
cyclic thermal loading. This confirmed the functionality of presented energy harvesting
device using SMA actuators.
Then, Heat transfer equations for annular flow were modeled. The relationship
between SMA temperature and shaft angular rotation was derived from a semi-empirical
SMA stress-temperature model and 2nd order Ozdemir’s SMA stress-strain equations. The
simulated generator shaft rotation and generator voltage are in close agreement with the
corresponding experimental results.
Computational fluid dynamics simulation of EHP was performed in the 1112mm
long 1/2” stainless steel and Chlorinated Polyvinyl Chloride (CPVC) pipes with linear
SMA actuators centered at the pipe axis. The simulation results exhibited that there is
turbulent water flow near to the entrance and then the flow becomes laminar. SMA
actuator heating times inside the CPVC pipe was faster than that of stainless steel pipe.
The simplified energy harvesting prototype (SEHP) was built with linear generator
to optimize energy conversion factor of the EHP. The 12.7mm, 15.9mm and 19mm spring
diameters of 1.9mm wire diameter SMA actuator were produced in the lab and tested in
3/4” stainless steel pipe, in 3/4” CPVC pipe, and in 1.25” Polycarbonate (PolyC) pipe. The
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15.9mm and CPVC pipe were obtained as optimal spring diameter and pipe material,
respectively. 5s was determined as optimal SMA heating and cooling cycle times for the
optimal SMA actuators in the 3/4” CPVC pipe. The optimal spring SMA in the CPVC was
tested for 60s and generated near to 8000mJ energy. Based on experimental results and
analysis, EHP has a strong potential to recuperate low temperature wasted heat.
At the end, novel self-sufficient flow valve was designed to alternately switch the
hot and the cold water flow in the EHP so that SMA actuators can be heated and cooled
without external energy supply.
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DEDICATION

This dissertation is dedicated to my wife and my mom
Rahel Bogale and Abaynesh Lekew
Who made all this possible,
for their endless love, support, encouragement and patience.

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ACKNOWLEDGMENTS

Firstly, I am thankful to the almighty God for giving me the courage and the
strength to accomplish this dissertation. I am highly grateful to my advisor and mentor
Dr. Erik Engeberg for his encouragement, consistent help, most importantly his valuable
instruction in academic and technical areas. The accomplishment of this dissertation
would not have been possible without his magnificent support.
I would like to extend my heartfelt gratitude to my acting advisor Dr. Celal Batur
as he has served as my acting advisor here in the University of Akron, to Dr. Hariharan
Subramaniya, Dr. D. Dane Quinn, Dr. Desale Habtzghi, Dr. Robert J. Veillette, and Dr.
Minel Braun for their valuable input into my research. In addition, I must extend my
gratitude towards my other committee member Dr. Alper Buldum for his time on reading
and evaluating my dissertation.
I would also like to thank Dr. Gregory N. Morscher for his patience and for giving
me his lab space to conclude this dissertation. The financial support from the graduate
school and the mechanical department is greatly appreciated. Of course, I am highly
thankful to my colleagues Benjamin A Kent, Zahi and Zaki. Discussion on the academic
and the technical issues with them always energized me to accomplish my research
objectives.
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I greatly thank my beloved wife Rahel Bogale and sons: Yeabkal and Dillabo for
their love, patience and support. My special thanks go to my other families specially my
mom Abaynesh L. Bogale for being the cornerstone towards my success and for
mentioning my name in each and every prayer she made in front of God.

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TABLE OF CONTENTS
Page
LIST OF TABLES ............................................................................................................ xii
LIST OF FIGURES ......................................................................................................... xiv
CHAPTER
I. INTRODUCTION ........................................................................................................1
1.1 Motivation ....................................................................................................2
1.2 Research Objectives .....................................................................................5
II. BACKGROUND AND LITERATURE REVIEW .................................................9
2.1 Heat ..............................................................................................................9
2.2 Heat Quantity ...............................................................................................9
2.3 Thermal Efficiency and CO Emission ......................................................10
2
2.4 Economic Feasiblity of Waste Heat Recovery ..........................................11
2.5 Waste Heat .................................................................................................13
2.6 Waste Heat Recovery Techniques in Power Plant .....................................14
2.6.1 Reheat……. ............................................................................ 14
2.6.2 Regenaration ........................................................................... 14
2.7 Industrial Waste Heat Temperature and Technologies ..............................16
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2.8 Energy Harvesting Techniques in Automotive ..........................................16
2.8.1 Hybrid Pneumatic Power Systems .......................................... 17
2.8.2 Electric Turbo Compounding (ETC) Systems ........................ 19
2.8.3 Organic Rankin Cycle (ORC) ................................................. 20
2.8.4 Thermoelectric Power Generation (TG) ................................. 21
2.8.5 SMA Actuator Heat Engine .................................................... 22
III. PRELIMINARY RESEARCH: ENERGY HARVESTING PROTOTYPE
TEST ......................................................................................................................24
3.1 Energy Harvesting Prototype (EHP) ..........................................................24
3.2 Energy Harvesting Prototype without Load ..............................................26
3.2.1 Result and Discussion ............................................................. 29
3.3 Energy Harvesting Prototype with Load Capacitors .................................33
3.3.1 Result ...................................................................................... 35
3.4 Discussion ..................................................................................................37
3.5 Concluding Remarks ..................................................................................39
IV. SMA STRESS-TEMPERATURE EXPERIMENT ...............................................41
4.1 Experimental Method.................................................................................41
4.2 Spring SMA Production .............................................................................44
4.3 Test Procedures ..........................................................................................49
4.4 Result and Discussion ................................................................................52
4.4.1 Single Cycle Heating .............................................................. 52
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