Development of Air-to-Air Heat Pump Simulation Program with Advanced Heat Exchanger ...

260 Pages·2007·1.81 MB·English

DEVELOPMENT OF AIR-TO-AIR HEAT PUMP
SIMULATION PROGRAM WITH ADVANCED
HEAT EXCHANGER CIRCUITRY ALGORITHM
by
IP SENG IU
Bachelor of Science/Electromechanical Engineering
The University of Macau
Taipa, Macau SAR
1999
Master of Science/Mechanical Engineering
Oklahoma State University
Stillwater, OK
2002
Submitted to the Faculty of the
Graduate College of the
Oklahoma State University
in partial fulfillment of
the requirements for
the Degree of
DOCTOR OF PHILOSOPHY
May 2007
UMI Number: 3259575
UMI Microform3259575
Copyright2007 by ProQuest Information and Learning Company.
All rights reserved. This microform edition is protected against
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DEVELOPMENT OF AIR-TO-AIR HEAT PUMP
SIMULATION PROGRAM WITH ADVANCED
HEAT EXCHANGER CIRCUITRY ALGORITHM
Dissertation Approved:
Daniel E. Fisher
Dissertation Advisor
Jeffrey D. Spitler
Afshin J. Ghajar
J. Robert Whiteley
A. Gordon Emslie
Dean of the Graduate College
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ACKNOWLEDGMENTS
There are many people I would like to thank for their supports for this
accomplishment. Without any one of them I am not sure if I am able to come to this
point to write the acknowledgments. My family members are supportive all the way. My
parents raised all of us during the tough time but I did not realize that when I was kid. I
had a really good time in the childhood. Thank you all. This dissertation is dedicated to
my late father, Son Iu. I always like to be around with him and hope that he can feel the
joy with me in another world.
My wife, Kahori and her family are also very supportive. Mr. and Mrs.
Matsunaga always treat me like their son. I still thought I could marry with Kahori when
I was a student is a generous gift from them. Kahori is the real director of this
dissertation. I would have just gone to another direction if without her support.
When I was still a student in the University of Macau, Dr. Tam always talked
about all the funs he had at OSU. I was intrigued by him and decided to come here some
day. I had a rough start at OSU but Dr. Ghajar was willing to help me through. I always
think that I owe him this one.
My academic advisor, Dr. Fisher, has guided me through my Master and Doctoral
studies. He has made me realize how important and useful FORTRAN is. The computer
language that I used to despise. I guess right now I cannot live without it anymore. It is a
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roller coaster ride with him in the last seven years. It is a great learning experience
though. I have learned a lot from him. He also reminds me the joy of being in a big
family.
Dr. Spitler is the first professor that I was referred to by Dr. Tam. I am glad he is
in my committee. He is a very knowledgeable professor. I should have realized his
academic greatness earlier. OSU is very fortunate to have him around.
I really appreciate my outside committee member, Dr. Whiteley for reading all of
my writings. I had no clue what kind of professor he is when I asked him to join my
committee. Thank you Dr. Fisher for the recommendation. Dr. Whiteley is an outside
committee member like no others. I am glad I can have him in my committee.
Dr. Bansal and Dr. Rees are two former visiting professors at OSU. They
provided great help at the beginning of this research. If without their help, I would not
know what I would be writing for this research.
Ben Alexander is a very skillful technician. He helped me in several different
projects and set up the pseudo psychometric room. He seemed enjoyed working at OSU
but I believe he deserves something better than that. If I am looking for someone to help
in the future, he will be the first on my list.
I also like to thank the people at York, now Johnson Controls, Inc. for their
technical support. Charles Obosu started this project and helped me set up all the
experiment in the lab. Nathan Weber always provided me valuable inputs to improve the
simulation program. He has been fun to work with since we worked together at OSU.
John Knight took over the project later and he has brought the simulation program to
another level. I have learned a lot from him in the practical perspective. He has also
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helped me find all the resources that I need to finish this work. Steven Jones helped me
run all the experiment patiently. He was even willing to squeeze his work schedule to get
the data for me. I really appreciate his help.
I guess I cannot say enough thank you to all of them but than you all!
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TABLE OF CONTENTS
Acknowledgments.............................................................................................................iii
List of Tables...................................................................................................................viii
List of Figures....................................................................................................................ix
Nomenclature...................................................................................................................xii
1. Introduction....................................................................................................................1
1.1. Background..............................................................................................................1
1.2. Objectives.................................................................................................................3
1.3. Unique Contributions...............................................................................................5
1.4. Overview..................................................................................................................6
2. Review of Literature......................................................................................................8
2.1. Component Models..................................................................................................8
2.2. System Simulation Algorithms..............................................................................18
2.3. Refrigerant Properties............................................................................................25
2.4. Refrigerant Oil Mixture..........................................................................................27
2.5. Circuiting Algorithms............................................................................................27
2.6. Local Air Side Heat Transfer Coefficients.............................................................33
3. Mathematical Models..................................................................................................37
3.1. Compressor............................................................................................................37
3.2. Expansion Device...................................................................................................39
3.3. Distributor..............................................................................................................42
3.4. Heat Exchangers.....................................................................................................44
3.5. System Charge.......................................................................................................75
3.6. Interconnecting Pipes.............................................................................................76
3.7. Filter Drier..............................................................................................................76
3.8. Accumulator...........................................................................................................77
3.9. Refrigerant Properties............................................................................................81
3.10. Refrigerant-Oil Mixture.......................................................................................82
3.11. System Simulation Algorithms............................................................................84
4. Model Evaluation.........................................................................................................89
4.1. Compressor............................................................................................................89
4.2. Short Tube Orifice..................................................................................................91
4.3. Condenser...............................................................................................................94
4.4. Evaporator..............................................................................................................97
4.5. Circuiting................................................................................................................99
4.6. System Simulation...............................................................................................104
4.7. System Simulation with Row-by-Row Heat Transfer Coefficient......................108
5. Development of Row-by-Row Heat Transfer Coefficient......................................110
5.1. Experimental Method...........................................................................................110
5.2. Test Conditions....................................................................................................114
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5.3. Derivation of the Heat Transfer Coefficient........................................................115
5.4. Uncertainty Analysis............................................................................................118
5.5. Verification of Experimental Method..................................................................124
5.6. Louvered Fin Heat Transfer Coefficients............................................................131
5.7. Correlation Development.....................................................................................137
5.8. Evaluation of Row-by-Row Louvered Fin Heat Transfer Coefficients for System
Simulation ..................................................................................................................146
6. Model Validations......................................................................................................150
6.1. Experiment for Model Validations.......................................................................150
6.2. Test Conditions....................................................................................................153
6.3. Component Level Validation...............................................................................154
6.4. System Level Validation......................................................................................167
6.5. Validation with Additional Data..........................................................................174
7. Summary and Recommendations.............................................................................189
7.1. Summary of Results.............................................................................................189
7.2. Recommendations for Future Work.....................................................................192
8. Reference....................................................................................................................195
9. Bibliography...............................................................................................................207
9.1. Air Side Heat Transfer and Pressure Drop...........................................................207
9.2. Airflow Maldistribution.......................................................................................208
9.3. Charge..................................................................................................................209
9.4. Compressor..........................................................................................................210
9.5. Dehumidification..................................................................................................210
9.6. Expansion Device.................................................................................................212
9.7. Heat Exchangers...................................................................................................212
9.8. Heat Pump Models...............................................................................................213
9.9. Miscellaneous.......................................................................................................214
9.10. Refrigerant Side Heat Transfer and Pressure Drop............................................215
10. Appendix...................................................................................................................218
10.1. Verification of Flat Fin Heat Transfer Coefficients...........................................218
10.2. Louvered Fin Normalized Row-By-Row j-factors............................................221
10.3. Louvered Fin Scaled Row-By-Row Nusselt Number........................................223
10.4. Nusselt Number Correlations.............................................................................226
10.5. York Data Boundary Conditions........................................................................227
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LIST OF TABLES
Table 2.1 Connection arrays for the sample circuit of Ellison et al. (1981)......................29
Table 2.2 Adjacency matrix for the sample circuit of Ellison et al. (1981)......................31
Table 2.3 Junction-tube connectivity matrix for the sample circuit..................................33
Table 3.1 Empirical coefficients for the short tube model Payne and O'Neal (2004).......41
Table 3.2 Circuit table for the sample circuit....................................................................66
Table 3.3 Junction numbering for the sample circuit in Figure 3.6...................................70
Table 3.4 Flow rate per ton for different refrigerants (ARI 2004).....................................77
Table 4.1 Test coil geometry.............................................................................................94
Table 4.2 Test coil geometry for circuiting algorithm evaluations..................................101
Table 4.3 Sample system for the evaluations of system simulation................................105
Table 5.1 Measuring instruments and uncertainties for the coil tests..............................112
Table 5.2 Coil test matrix.................................................................................................115
Table 5.3 Circuit pressure drop at 0.91 m3.hr-1 water flow rate.......................................121
Table 5.4 Empirical coefficients for the Nusselt number correlation, Equation (5.48)...140
Table 5.5 Empirical coefficients for the Nusselt number conversion, Equation (5.51)...145
Table 5.6 Coil specifications for the evaluation of row-by-row louvered fin coefficients.
..........................................................................................................................................146
Table 6.1 Coil geometry..................................................................................................152
Table 6.2 Instruments and uncertainties for the system tests...........................................152
Table 6.3 Matrix for model validation (52% indoor relative humidity, 50 m3.min-1
outdoor flow rate)............................................................................................................154
Table 6.4 Coefficients for the Copeland compressor ZR34K3-PFV...............................157
Table 6.5 Refrigerant side boundary conditions for system level validation..................169
Table 6.6 York data system configuration.......................................................................175
Table 6.7 York data boundary conditions........................................................................178
Table 6.8 Test conditions for the York systems..............................................................178
Table 6.9 Short tube model validation with the York data System 30............................183
Table 10.1 Boundary conditions for compressor model validation.................................227
Table 10.2 Boundary conditions for short tube model validation...................................230
Table 10.3 Refrigerant side boundary conditions for condenser model validation.........230
Table 10.4 Refrigerant side boundary conditions for evaporator model validation........233
Table 10.5 Refrigerant side boundary conditions for system level validation................235
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LIST OF FIGURES
Figure 2.1 Discretization of heat exchanger tubes.............................................................12
Figure 2.2 Zone-by-zone method: Equivalent circuit assumption.....................................13
Figure 2.3 Successive substitution: System simulation algorithm.....................................20
Figure 2.4 Successive substitution: System design calculation.........................................23
Figure 2.5 Sample circuit (Ellison et al. 1981)..................................................................29
Figure 2.6 Equivalent electrical circuit for the sample heat exchanger circuit..................32
Figure 2.7 Row-by-row j-factor (Rich 1975).....................................................................34
Figure 3.1 Heat exchanger segment-by-segment discretization........................................46
Figure 3.2 Heat exchanger element...................................................................................46
Figure 3.3 Side view of heat exchanger showing staggered tube pattern..........................49
Figure 3.4 Sample circuit with re-assigned tube numbers.................................................65
Figure 3.5 Joining and splitting circuits.............................................................................66
Figure 3.6 Illustrative example for the nodal admittance formulation method.................70
Figure 3.7 Algorithm for heat exchanger model................................................................75
Figure 3.8 Geometry definitions for the accumulator model.............................................78
Figure 3.9 Simulation algorithm for Orifice and TXV Design..........................................85
Figure 3.10 Simulation algorithm for fixed orifice simulation..........................................87
Figure 3.11 Simulation algorithm for TXV simulation.....................................................88
Figure 4.1 Compressor evaluation: Mass flow Rate (Tested at 11.1 K superheat)...........91
Figure 4.2 Compressor evaluation: Power consumption (Tested at 11.1 K superheat).....91
Figure 4.3 Orifice model evaluation: Change of inlet saturation temperature..................92
Figure 4.4 Orifice model evaluation: Change of orifice diameter.....................................93
Figure 4.5 Test Coil for heat exchanger model evaluations..............................................94
Figure 4.6 Condenser model evaluation: Capacity............................................................95
Figure 4.7 Pressure-Enthalpy diagram for different refrigerants.......................................96
Figure 4.8 Condenser model evaluation: Mass inventory.................................................97
Figure 4.9 Evaporator model evaluation: Capacity...........................................................98
Figure 4.10 Evaporator model evaluation: Mass Inventory...............................................99
Figure 4.11 Sample circuits for circuiting model evaluations.........................................100
Figure 4.12 Circuiting model evaluation: Capacity.........................................................101
Figure 4.13 Circuiting model evaluation: Pressure drop.................................................102
Figure 4.14 Circuiting model evaluation: Refrigerant distribution (mass flow rate = 0.032
kg.s-1)................................................................................................................................103
Figure 4.15 Coil circuitry for the sample system.............................................................105
Figure 4.16 Evaluation of system simulation: Capacity..................................................107
Figure 4.17 Catalog data for the York heat pump BHH048............................................108
Figure 4.18 Comparison of row-by-row and overall flat fin heat transfer coefficients...109
Figure 5.1 Test rig for coil performance measurement....................................................110
Figure 5.2 Coil instrumentation.......................................................................................113
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