Solar Hydrogen Fuel Cell Water Heater (Educational Stand)

Cairo University Faculty of Engineering Mechanical Power Dept.

Solar Hydrogen Fuel Cell Water Heater Educational StandB.Sc. Graduation Project 2010

Supervised byProf. Dr. Hany Khater Prof Dr. Adel Khalil Dr. Galal Mostafa

Introduced byAhmed Ali Ali El-Beltagy Khaled Ali Ali El-Beltagy Mahmoud Mohamed Emam Radia M. Fekry El-Deeb Tarek Mahmoud El-Gammal

The existence of energy was never a problem as much as how to extract, transform, and store it into a useful form. Human history tells us stories about fights over energy sources from the simplest food fights, which is the source of energy for the body, to the world wars over the sources of fossil fuels in modern time. Therefore, energy is the soul of life and existence. Human civilization is based on the use of energy in more effective ways to increase the industrial production and human comfort.

One of the most important trends of energy sources in the 21st century is Solar Energy. Solar Energy is a clean, renewable and cheap, actually free-cost, energy source. But the main disadvantages are that it is not available at night, in addition to the high utilization cost. Consequently storing energy is an important issue in order to provide the continuous availability of energy.

Fuel cells offer cleaner, more-efficient alternatives to the combustion of gasoline and other fossil fuels. They have the potential to replace the internal combustion engines in vehicles and provide power in stationary and portable power applications because they are energy-efficient, clean, and fuel-flexible. Hydrogen or any hydrogen-rich fuel can be used by this emerging technology. It is visualized that as fossil fuels run out, hydrogen will become the major world fuel and energy vector.

Cairo University Faculty of Engineering Mechanical Power Dept.

Solar Hydrogen Fuel Cell Water HeaterB.Sc. Graduation Project ( 2010 )

(Educational Stand)Supervised byProf. Dr. Hany Khater Prof Dr. Adel Khalil Dr. Galal Mostafa

Introduced byAhmed Ali Ali El-Beltagy Khaled Ali Ali El-Beltagy Mahmoud Mohamed Emam Radia M. Fekry El-Deeb Tarek Mahmoud El-Gammal

American Society of Heating, Refrigerating, and Air-Conditioning Engineers

The title of your project is very challenging and demonstrates an exciting approach in teaching. I wish you very successful project realization on the benefit of Cairo students, and in addition might be as an advanced Educational Stand it could become a model for broader world-wide implementation. With the very best wishes and regards

MarijaTodorovic, Regional Vice Chair, Student Activities Committee, RAL

Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010

ii

CONTENTSLIST OF FIGURES.............................................................................................................. viii LIST OF TABLES................................................................................................................ xiv NOMENCLATURE .............................................................................................................. xv ACKNOWLEDGMENT .................................................................................................... xviii PREFACE ............................................................................................................................. xix Chapter 1: INTRODUCTION ............................................................................................... 1 Chapter 2: LITERATURE REVIEW ................................................................................... 4 2.1. Introduction ................................................................................................................ 5 2.2. Solar Panels ................................................................................................................ 5 2.2.1. Standing Seam Metal Roofing ....................................................................... 5 2.2.2. Vision Glass ................................................................................................... 5 2.2.3. MITs Solar Concentrator Window ............................................................... 5 2.3. Electrolysis ................................................................................................................. 7 2.3.1. Sea water (Brine) Electrolysis ....................................................................... 7 2.4. Fuel Cells .8 2.4.1. Stationary Systems......................................................................................... 8 2.4.2. Transportation (Automotives) ....................................................................... 8 2.4.3. Portable Micro-Power .................................................................................... 9 2.5. Commercial Applications......................................................................................... 10 2.5.1. Home Energy Station ................................................................................... 10 2.6. Experimental Applications ....................................................................................... 11 2.6.1. Dr FuelCell Science Kit ............................................................................... 11 2.6.2. Dr FuelCell Model Car ................................................................................ 14 2.6.3. Fuel Cell Kit, Green Utility House .............................................................. 14Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 iii

2.6.4. Fuel Cell Car Science Kit ............................................................................ 18 2.7. Conclusion................................................................................................................ 19 2.8. References ................................................................................................................ 20 Chapter 3: PREPARATION ................................................................................................ 21 3.1. Electrolysers ............................................................................................................. 22 3.1.1. Esperanza ..................................................................................................... 22 3.1.2. The Fuel Cell Store Electrolysers ................................................................ 22 3.2. Fuel Cells 24 3.2.1. Convection fuel cell stack ............................................................................ 24 3.2.2. H-Series Fuel Cells ...................................................................................... 26 3.3. Further Details .......................................................................................................... 29 3.4. Our Choice ............................................................................................................... 31 3.5. Steps towards Purchasing ......................................................................................... 31 3.6. References ................................................................................................................ 34 Chapter 4: COMPONENTS ................................................................................................. 35 4.1. SOLAR CELL .................................................................................................................. 36 4.1.1. Brief History ................................................................................................ 37 4.1.2. Solar Radiation ............................................................................................ 37 4.1.3. Photovoltaic Solar Cell Systems .................................................................. 44 4.1.4. Solar Energy in Egypt .................................................................................. 53 4.1.5. References.................................................................................................... 56 4.2. ELECTROLYSER ................................................................................................... 57 4.2.1. Water Electrolysis Technology.................................................................... 58 4.2.2. Types of Electrolysers ................................................................................. 59 4.2.3. Elecrolyser and Fuel Cell............................................................................. 61 4.3. FUEL CELL ............................................................................................................. 62 4.3.1. Introduction.................................................................................................. 63 4.3.2. History ......................................................................................................... 63Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 iv

4.3.3. Components and their functions .................................................................. 64 4.3.4. Operation ..................................................................................................... 65 4.3.5. Types of fuel cell ......................................................................................... 66 4.3.6. PEM Fuel Cell (PEMFC)............................................................................. 68 4.3.7. References.................................................................................................... 77 4.4. ELECTRIC LOADS ................................................................................................ 78 4.4.1. The first load: Light Emitting Diode (LED) ................................................ 79 4.4.2. The second load: Fan ................................................................................... 79 4.4.3. The third load: Electric Heater .................................................................... 84 4.4.4. References.................................................................................................... 92 Chapter 5: MODELLING AND TESTING ........................................................................ 93 5.1. Solar Radiation ......................................................................................................... 94 5.1.1. Definitions ................................................................................................... 94 5.1.2. Modeling Results ......................................................................................... 97 5.2. Photovoltaic Panel .................................................................................................... 99 5.2.1. Technical Data ............................................................................................. 99 5.2.2 Modeling of Photovoltaic cell ...................................................................... 99 5.2.3. PV Modelling Results ................................................................................ 104 5.3. PEM Electrolyser ................................................................................................... 107 5.3.1. Technical Data ........................................................................................... 107 5.3.2. Modelling of the PEM Electrolyser ........................................................... 108 5.3.3. PEM Modelling Results ............................................................................. 112 5.4. PEM Fuel Cell ........................................................................................................ 117 5.4.1. Technical Data ........................................................................................... 117 5.4.2. Modeling of the PEM Fuel Cell................................................................. 118 5.4.3. PEM Fuel Cell Modelling Results ............................................................. 122 5.5. References .............................................................................................................. 127 Chapter 6: MEASURING DEVICES AND CONTROL ................................................. 130Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 v

6.1. Introduction ............................................................................................................ 131 6.2. Measurements ........................................................................................................ 132 6.2.1. General ....................................................................................................... 132 6.2.2. Electricity Measurements .......................................................................... 132 6.2.3. Thermal Measurements ............................................................................. 133 6.3. Programming and Control ...................................................................................... 135 6.3.1. Control of Lamp Position .......................................................................... 135 6.3.2. Testing and Assurance ............................................................................... 141 6.3.3. Programming ............................................................................................. 143 6.4. References .............................................................................................................. 156 Chapter 7: BILL OF MATERIALS AND COST............................................................. 157 Chapter 8: FABRICATION AND ASSEMBLY .............................................................. 161 8.1. Educational Stand Fabrication ............................................................................... 162 8.1.1. Bench Fabrication ...................................................................................... 162 8.1.2. Solar Lamp Movement Fabrication ........................................................... 169 8.2. Educational Stand Assembly.................................................................................. 171 Chapter 9: OPERATING PROCEDURE OF THE EDUCATIONAL STAND ........... 174 9.1. Experiment 1: Investigating the Solar Panel .......................................................... 175 9.1.1. Procedure ................................................................................................... 175 9.1.2. Evaluation .................................................................................................. 176 9.2. Experiment 2: Investigating the characteristic curve of the electrolyser ............... 177 9.2.1. Procedure ................................................................................................... 177 9.2.2. Evaluation .................................................................................................. 178 9.3. Experiment 3: Investigating the characteristic curve of a fuel cell ........................ 179 9.3.1. Procedure ................................................................................................... 179 9.3.2. Evaluation .................................................................................................. 180 9.4. Experiment 4: Solar Heater .................................................................................... 181 9.4.1. Instructions ................................................................................................ 181Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 vi

9.4.2. Evaluation .................................................................................................. 182 9.5. Experiment 5: Fuel Cell Heater.............................................................................. 183 9.5.1. Procedure ................................................................................................... 183 9.5.2. Evaluation .................................................................................................. 183 9.6. Other Experiments ................................................................................................. 184 Chapter 10: TESTS AND RESULTS ................................................................................ 185 10.1. Introduction .......................................................................................................... 186 10.2. Results and Discussion ......................................................................................... 186 10.2.1. Electrolyser Characteristics ..................................................................... 186 10.2.2. Single Fuel Cell ....................................................................................... 187 10.2.3. Fuel Cells in connection .......................................................................... 189 10.2.4. Heaters ..................................................................................................... 192 10.2.5. Solar Cell performance ............................................................................ 195 10.3. Further Interpretation ........................................................................................... 205 10.3.1. Solar Cell ................................................................................................. 205 10.3.2. Electrolyser .............................................................................................. 205 10.3.3. Fuel Cell................................................................................................... 206 APPENDICES ..................................................................................................................... 208 Appendix A: THERMOPHYSICAL PROPERTIES OF MATTERS .................................. 209 Appendix B: FREE CONVECTION HEAT TRANSFER CORRELATIONS .................... 215 Appendix C: SOLAR CELL ACTUAL CHARACTERISTIC CURVEINVESTIGATION 219 Appendix D: NI USB-6008 DATA SHEET ......................................................................... 230 Appendix E: PT100 TEMPERATURE SENSOR DATA SHEET ....................................... 263 Appendix F: EWTR 910 TEMPERATURE PANEL DATA SHEET .................................. 265 Appendix G: MATLAB CODE ............................................................................................ 270 Appendix H: HEATER EXPERIMENTS ............................................................................. 294


vii

LIST OF FIGURESFigure 1.1: Solar Hydrogen Fuel Cell Electric Heater Educational Stand ........................................ 2

Figure 2.1: MMU solar roof .............................................................................................................. 6 Figure 2.2: Organic solar concentrators collect and focus different colors of sunlight. Solar cells can be attached to the edges of the plates. By collecting light over their full surface and concentrating it at their edges, these devices reduce the required area of solar cells and consequently, the cost of solar power. Stacking multiple concentrators allows the optimization of solar cells at each wavelength, increasing the overall power output. ............................................................................. 7 Figure 2.3: Toshiba Dynario mobile charger .................................................................................. 9 Figure 2.4: From left NEC, Toshiba, Samsung laptops................................................................... 10 Figure 2.5: Home Energy Station (HES III) .................................................................................... 10 Figure 2.6: Dr Fuel cell science kit.................................................................................................. 11 Figure 2.7: Dr Fuel cell model Car .................................................................................................. 14 Figure 2.8: Fuel Cell Kit, Green Utility House ............................................................................... 17 Figure 2.9: Fuel cell car science kit ................................................................................................. 18

Figure 3.1: Purchase Invoice ........................................................................................................... 32

Figure 4.1: Variation of extraterrestrial solar radiation with time of year ..................................... 38 Figure 4.2: Angles .......................................................................................................................... 40 Figure 4.3: Declination angle ...................................................................................................... 41 Figure 4.4: Latitude angle ........................................................................................................... 41 Figure 4.5: Hour angle ................................................................................................................ 42 Figure 4.6: Beam radiation on horizontal and tilted surface .......................................................... 43


viii

Figure 4.7: Behaviour of light shining on a solar cell. (1) Reflection and absorption at top contact. (2) Reflection at cell surface. (3) Desired absorption. (4) Reflection from rear out of cellweakly absorbed light only. (5) Absorption after reflection. (6) Absorption in rear contact....................... 46 Figure 4.8: The effect of light on the current-voltage characteristics of a p-n junction .................. 47 Figure 4.9: Typical representation of an I-V curve, showing short-circuit current (Isc and opencircuit voltage (Voc) points, as well as the maximum power point (Vmp, Imp) ............................ 47 Figure 4.10: The effect of temperature on the I-V characteristics of a solar cell ............................ 49 Figure 4.11: Parasitic series and shunt resistances in a solar cell circuit ........................................ 50 Figure 4.12: The effect of series resistance on fill factor ................................................................ 50 Figure 4.13: A typical laminated module structure (EVA stands for Ethylene Vinyl Acetate) ...... 52 Figure 4.14: Solar radiation world map ......................................................................................... 53 Figure 4.15: The average annual direct solar radiation (normal incidence) in Egypt in kWh/d .... 54 Figure 4.16: Kuraymat power station site ...................................................................................... 55 Figure 4.17: Water Electrolysis principle ........................................................................................ 58 Figure 4.18: Schematic drawing of a PEM cell with cell reactions ................................................ 60 Figure 4.19: Schematic drawing of a Solid Oxide Electrolyser ...................................................... 61 Figure 4.20: Fuel cell ...................................................................................................................... 63 Figure 4.21: Schematic diagrams for the PEMFC basic components and the reactants/ions/products flow ................................................................................................................................................. 65 Figure 4.22: An example of a membrane electrode assembly (MEA). The membrane is a little larger than the electrodes that are attached. These electrodes have the gas diffusion layer attached, which gives it a grainy texture. The membrane is typically 0.05 to 0.1mm thick, the electrodes are about 0.03mm thick, and the gas diffusion layer is between 0.2 and 0.5-mm thick. ................................ 69 Figure 4.23: Cathodeelectrolyteanode construction of a fuel cell ............................................... 70 Figure 4.24: Electrode reactions and charge flow for an acid electrolyte fuel cell. Note that although the negative electrons flow from anode to cathode, the conventional current flows from cathode to anode. .............................................................................................................................................. 70 Figure 4.25: Simple edge connections of three cells in series ........................................................ 71 Figure 4.26: Single cell with end plates for taking current from all over the face of the electrodes and also supplying gas to the whole electrode. ..72 Figure 4.27: Two bipolar plates of very simple design. There are horizontal grooves on one side and vertical grooves on the other. ......................................................................................................... 73Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 ix

Figure 4.28: Voltage-current curve ideal & actual ......................................................................... 74 Figure 4.29: Chart to summarize the applications and main advantages of fuel cells of different types, and in different applications. 76 Figure 4.30: Red LED ..................................................................................................................... 79 Figure 4.31: LED symbol ................................................................................................................ 79 Figure 4.32: Left -Hand-Rule for current-carrying ......................................................................... 80 Figure 4.33: Current-Carrying Conductor in a Magnetic Field ....................................................... 81 Figure 4.34: PMDC Motor .............................................................................................................. 82 Figure 4.35: Schematic view for PMDC ........................................................................................ 82 Figure 4.36: Right-Hand Rule for Motors ....................................................................................... 83 Figure 4.37 :DC motor operation ................................................................................................... 83 Figure 4.38: Theory of operation of PMDC Motor ........................................................................ 84 Figure 4.39: Conduction in a solid cylinder with uniform heat generation ..................................... 85 Figure 4.40: Free convection boundary layer transition on a vertical plate .................................... 89 Figure 4.41: Hollow cylinder with convective surface conditions .................................................. 91

Figure 5.1 : Variation of percentage of diffuse radiation with clearness index.97 Figure 5.2: Variation of total hourly radiation with solar hour..98 Figure 5.3: Single-diode model of the theoretical PV cell and equivalent circuit of a practical PV device including the series and parallel resistances.100 Figure 5.4: Characteristic IV curve of the PV cell. The net cell current I is composed of the lightgenerated current Ipv and the diode current Id..101 Figure 5.6: Variation of PV maximum power through sunlight duration104 Figure 5.6: PV Power-Voltage curve at maximum intensity of the specific day.105 Figure 5.7: Variation of optimum voltage through sunlight duration..105 Figure 5.8: PV I-V curve at maximum intensity of the specific day106 Figure 5.9: Variation of photovoltaic efficiency through sunlight duration106 Figure 5.10: Variation of Electrolyser voltage with the solar hour..112 Figure 5.11: Variation of Electrolyser current with the solar hour..113Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 x

Figure 5.12: Variation of Electrolyser hydrogen production with the solar hour113 Figure 5.13: Variation of Electrolyser power with the solar hour114 Figure 5.14: Variation of Electrolyser efficiency with the solar hour.115 Figure 5.15: Variation of Electrolyser heats with the solar hour.116 Figure 5.16: Electrolyser characteristic curves at noon117 Figure 5.17: Variation of Fuel cell current with the solar hour122 F Figure 5.18: Variation of Fuel cell voltage with the solar hour123 Figure 5.19: Variation of Fuel cell power with the solar hour.123 Figure 5.20: Variation of Fuel cell efficiency with the solar hour angle.123 Figures 5.21: Characteristic curves of single fuel cell operating with all hydrogen flow..124 Figures 5.22: Characteristic curves of single fuel cell operating with half hydrogen flow in parallel and series connections.125 Figures 5.23: Characteristic curves of two fuel cells operating with all hydrogen flow (parallel and series connections)..126 Figure 6.1: Voltmeter and Ammeter Circuits..132 Figure 6.2: Thermistors Temperature ranges...134 Figure 6.3: non-terminated wires.134 Figure 6.4: Electric lamp fixed perpendicular to solar panel..135 Figure 6.5: H-Bridge circuit136 Figure 6.6: On the left: The lamp motor and on the right: The power screw which drives the lamp up and down136 Figure 6.7: Manual Control of Lamp..137 Figure 6.8: Transistor BC107..137 Figure 6.9: The final Manual and DAQ control circuit..138 Figure 6.10: Circuit connections views..139 Figure 6.11: The circuit drawn and marked on the board140 Figure 6.12: The fabricated board140 Figure 6.13: The final connected board top view140 Figure 6.14: 36V Motor142Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 xi

Figure 6.16: The H bridge lamp position control experimental circuit143 Figure 6.17: LabVIEW Block Diagrams..145 Figure 6.18: Lamp Controller..146 Figure 6.19: Front Panel of Measurement recorder.147 Figure 6.20: Measurement recorder Block Diagram148 Figure 6.21: Characteristic Curve Drawer Front Panel150 Figure 6.22: Characteristic Drawer Block Diagram (part 1)154 Figure 6.23: Characteristic Drawer Block Diagram (part 2)155

Figure 8.1: Early bench designs...162 Figure 8.2: Third bench design.163 Figure 8.3: AutoCAD bench isometric drawing...164 Figure 8.4: Solidworks bench and table 3D drawing...165 Figure 8.5: Solidworks bench and table 2D drawing...166 Figure 8.6: Fabricated bench and table.168 Figure 8.7: The photovoltaic placed on the inclined roof and the lamp is perpendicular on its face as the Sun..170 Figure 8.8: Lamp stand installation..170 Figure 8.9: The bench with the assembled components...171 Figure 8.10: Back of the bench.172 Figure 8.11: Monitor and DAQ Card...172 Figure 8.12: Different components assembled to the bench172

Figure 9.1: Solar Cell investigation..175 Figure 9.2: Electrolyser investigation..177 Figure 9.3: Single Fuel Cell investigation179 Figure 9.4: The fuel cells connected in series..180 Figure 9.5: The fuel cells connected in parallel...180Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 xii

Figure 9.6: Solar heater experiment.181 Figure 9.7: Fuel cell heater experiment182 Figure 10.1: Electrolyser voltage-current curve..186 Figure 10.2: Electrolyser P-I characteristic curve187 Figure 10.3: Single Fuel cell characteristic curve188 Figure 10.4: Single Fuel Cell power - current characteristic curve.189 Figure 10.5: V-I curve of a fuel cell in a set of cell..190 Figure 10.6: P-I curve of a fuel cell in a set of cells.191 Figure 10.7: Temperature change of 10 cm3 of water heated by a Heater powered by PV cell..192 Figure 10.8: Efficiency change of 10 cm3 water heated by a Heater powered by PV cell..193 Figure 10.9: Temperature change of 10 cm3 of water heated by a Heater powered by fuel cell.194 Figure 10.10: Efficiency change of 10 cm3 water heated by a Heater powered by PV cell.194 Figure 10.11: Theoretical and Experimental Voltage corresponding to maximum power through the day204


xiii

LIST OF TABLESTable 4. 1: Number of days (n) ....................................................................................................... 38 Table 4. 2: Angles description ........................................................................................................ 39

Table 4. 3: Fuel cell types and specifications ................................................................................. 67 Table 4. 4: Components Materials and Advantages ....................................................................... 68

Table 4.5: One-Dimentional, Steady-state Solutions to the Heat Equation for Uniform Heat Generation in a Solid Cylinder ........................................................................................................ 87

Table 5.1: Monthly fraction of sunshine hours................................................................................ 95 Table 5.2: Solar panel technical data ............................................................................................... 99 Table 5.3: PEM Electrolyser technical data .................................................................................. 107 Table 5.4: Constants used to calculate potential losses for low temperature PEMFC. ................. 120 Table 6.1: Truth Table ................................................................................................................... 139 Table 6.2: Block Diagram Main Components ............................................................................... 149 Table 6.3: Block Diagram Main Components ............................................................................... 152


xiv

NOMENCLATURESymbolA B Cp E E F

Description Surface area Magnetic field strength Specific heat at constant pressureStandard Nernst potential Potential Faraday constantIrradiance Extraterrestrial radiation Extraterrestrial radiation Solar constant solar radiation on the solar cell array Gravitational acceleration Irradiation or Radiant Exposure (Insolation ) in day Daily extraterrestrial radiation Monthly extraterrestrial radiationConvective heat transfer coefficient Average convective heat transfer coefficient Local convective heat transfer coefficient

Unit m2 Tesla J/kg.K V VC mol-1W/m2 W/m2 W/m2 W/m2 W/m2 m/s2 J/m2 J/m2 J/m2 W/m2.K W/m2.K W/m2.K Amp Amp Amp Amp

I IL Isc Impi io iL

G Go Gon Gsc GT g H Ho Hoh h hx

Current The light-generated current Cell short circuit current Cell maximum power current

Current density Exchange current density Limiting currentBoltzmanns constant Lenght Power Total heat transfer Chargevolumetric generation rate Heat transfer rate in the radial direction heat flux in the radial direction Local heat flux

A/m2 A/m2 A/m2J/K M Watt W CW/m3

kL

Pqo qr q r qx Q

q

WW/m2 W/m2


r ro

R

Resistance radius Outer radius

m m

xv

U V Voc Vmp

Ts T Tf T

T

Temperature Surface temperature Fluid temperatureFilm temperature

O

Temperature difference Overall heat transfer coefficient Voltage. Cell open circuit volt Cell maximum power volt

C or K o C, K o C, K o C, K C,K V V V

W/m2K

Greek LettersAbsorption coefficient Solar altitude angle Profile angle Latitude angle Declination angle Slope angle Surface azimuth angle Solar azimuth angle Hour angle Sunset or Sunrise hour angle Incident angle Zenith angle Wave length (m) Density (kg/m3)Dynamic viscosity or Viscosity (kg/s.m)

s p s s z

Chemical Symbols H2 H+ O2 OHH2O CO2 LiAlO2 CO3-2 CO Hydrogen molecule Hydrogen ion Oxygen molecule Hydroxyl ion Water molecule Carbon dioxide lithium aluminum oxide Carbon trioxide (ion) Carbon monoxide


xvi

Dimensionless groupsNu Gr Pr Ra Nusselt No. Nusselt No. based on average heat transfer coefficient Grashof No. Prandtl No. Rayleigh No.

Nu


xvii

ACKNOWLEDGMENTThe Graduation Project Team would like to express their gratitude and appreciation to the moral and financial support provided by The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). We would specially like to thank them for their interest in the topic of our project so that they selected it as the only non-American project funded this year. Progress made in our project would not have been possible without the direct guidance and persistent help of our supervisors Prof. Dr. Hany Khater, Prof. Dr. Adel Khalil and Dr. Galal Mostafa. Individually, we would like to express our gratitude and appreciation for our classmate and friend Mohamed Ahmed Youssef Ahmed for his great participation and deep working in the first part of the project. We would also like to express our gratitude to everybody who helped us with editorial, presentational, instrumental/technical, conceptual and peer interactive communication supports in preparing or doing our practical experiments so far, specially Prof. Dr. Hassan Rakh (NREA's Advisor for PV activities), Prof. Dr. Abd El-Wahed Eldeeb, Dr. Abd Almaged Ebraheem, Dr. Ahmed Kamel, Dr. Ahmed Attia (Shoubra Faculty of Engineering, Banha University), Eng. Abbas R. Rady (System Eng. Dept Manager and Solar Energy Projects Manager, Arab Org. for Industrialization, Arab British Dynamics), Eng. Osama Mowafaq, Teaching Assistants in Faculty of Engineering, Cairo University (Eng. Mohamed Beshr, Eng. Nadim M. Arafa, Eng. Ahmed Yehia, Eng. Mohamed Yafia, Eng. Rania Eldeeb Biomedical Engineering Dept, Eng, Ahmed Hassan Biomedical Engineering Dept, Eng. Yasser Electric Power Dept and Eng. Mohamed Shouka B.Sc. year, Electric Power Engineering Dept). Special gratitude also for the technicians in the Heat research lab (Mr. Abd Elrazek, Mr. Ali, Mr. Abbas, Mr. Tarek and Mr. Magdy Kamel) and Electric Power research lab, Faculty of Engineering, Cairo University.


xviii

PREFACEThe whole world is directing its efforts to get over the end of the non-renewable fuel era by introducing renewable and clean sources of energy. Electrolyser Fuel Cellsystems are one of the efficient ways of storing and producing energy which have great demands in engineering applications. Fuel Cells need Hydrogen and Oxygen to work. So, we can use Solar Energy. Solar energy is the greatest and free renewable source of energy as it is supplied by the sun. A Photovoltaic Solar Cell is a special type of solar cells in which solar energy is converted into an electric voltage (or current). The current will be used to produce hydrogen and Oxygen in an electrolyser using water electrolysis process. The hydrogen and Oxygen produced will first be stored and then be used by a fuel cell to produce current, heat and water. In large scale applications, the water vapor possessing the heat can then be passed through a countercurrent heat exchanger to heat water. Thus, hot water will be available for household, companiesetc using a natural everlasting source of energy. On a small scale water vapor cannot be used as it is too little for a 1.7Watt Fuel cell. Thus, in our project, only the current produced by the fuel cell will be used to heat water in a small heater or to run a simple load. A study of the characteristic curves of each of the photovoltaic cell, the electrolyser and the fuel cell will be performed by varying the input light intensity through varying the distance of an electric lamp from the solar panel. The knowledge of different heat and mass transfer mechanisms, system process design, equipment selection, material selection, instrumentation, data acquisition, data analysis, and performance tests are the required qualities to be gained by our team and passing it to junior students at the mechanical department. This is in addition to comparing between theoretical and actual experimental data which gives more sense of the difference between paper work and reality.


xix

Chapter 1

Introduction

Chapter 1

INTRODUCTION


1

Chapter 1

Introduction

The existence of energy was never a problem as much as how to extract, transform and store it into a useful form. Human history tells us stories about fights over energy sources from the simplest food fights, which is the source of energy for the body, to the world wars over the sources of fossil fuels in modern time. Therefore, energy is the soul of life and existence. Human civilization is based on the use of energy in more effective ways to increase the industrial production and human comfort. One of the most important trends of energy sources in the 21st century is Solar Energy. Solar Energy is a clean, renewable and cheap, actually free-cost, energy source. But the main disadvantages are that it is not available at night, in addition to the high utilization cost. Consequently storing energy is an important issue in order to provide the continuous availability of energy. Fuel cells offer cleaner, more-efficient alternatives to the combustion of gasoline and other fossil fuels. They have the potential to replace the internal combustion engines in vehicles and provide power in stationary and portable power applications because they are energy-efficient, clean, and fuel-flexible. Hydrogen or any hydrogen-rich fuel can be used by this emerging technology. It is visualized that as fossil fuels run out, hydrogen will become the major world fuel and energy vector.

Figure 1.1: Solar Hydrogen Fuel Cell Electric Heater Educational Stand

Solar-Hydrogen Fuel Cell Water Heater Educational Stand shown in Figure 4.1 is an educational kit that demonstrates the idea of the use of renewable energy in a power system module that enables the generation, use and instantaneous storage of energy. The Sun is a main source of vast amount of radiation energy that can be used in an economical way. Photovoltaic (PV) panels are now commercially available and considered as a permanent source of energy.Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 2

Chapter 1

Introduction

Solar-Hydrogen Fuel Cell system is the 'Giant leap' for renewable and clean energy storage: Solar-Hydrogen Fuel Cell System will allow the sun's energy to be used to split water into hydrogen and oxygen gases. Later, the oxygen and hydrogen may be recombined inside a fuel cell, creating carbon-free electricity to power your house or your electric car, day or night. This unprecedented process for energy storage has been developed by Nocera and Matthew Kanan, a postdoctoral fellow in Nocera's lab, MIT. This system could be applied as a Home Refueling Station in residential homes, as shown in Noceras system on the cover page of this chapter, factories and a wide range of applications. PV panels, an electrolyser and a fuel cell can form a power system assembled to undergo the generation, storage and continuous supply of clean energy. In our project the objective is to demonstrate this system to students and introduce the idea in the form of a laboratory experiment. They will understand, analyze and be able to study how the system works. They will be required to record different points on the characteristic curves of each of the solar cell, the electrolyser and the fuel cell by changing the input light intensity of an electric lamp by varying its distance from the solar cell. They will then, of course, be required to draw these curves. They will also study the two fuel cells first a single cell, then series and parallel connections curves. They will be required to compare them. The components of the experiment bench are: 1. Electric lamp 2. Photovoltaic solar cell 3. Single electrolyser 4. Two fuel cells 5. Variable resistance 6. Fan 7. Lamp 8. Two Electric heater

Theory of operation Light intensity produced by the electric lamp demonstrates the sun giving enough energy for the photovoltaic cell to produce enough current for water electrolysis that takes place in the electrolyser. Hydrogen produced by the electrolyser during the electrolysis process is used in the fuel cell membrane to be recombined with oxygen again and produce the required current according to the connected load. The fuel cell acts as a battery supplying the current according to load. Thus, by varying the load connected to the fuel cell, we can get different points on the characteristic curve and be able to draw it.


3

Chapter 2

Literature Review

Chapter 2 LITERATURE REVIEW


4

Chapter 2

Literature Review

2.1. IntroductionIn this section we will spotlight the latest technology and applications related to our solar-hydrogen electric system. As our system mainly deals with solar panels (photovoltaics), electrolysers and fuel cells, we will trace each component alone followed by the whole system.

2.2. Solar PanelsThe actual development of the efficiency of the photovoltaic (PV) panels and the start of its commercializing has run rapidly in the last few decades. Now the PV technology is spreading and replacing the fossil fuel shortage. However, it has the problem of high installing and operating costs as compared to conventional fossil fuel. The following are examples of some of the PV applications developing:

2.2.1. Standing Seam Metal RoofingStanding Seam Metal (SSM) roofing is a traditional roofing material that uses long, vertically sloped metal trays with raised edges. The trays are snapped together along the long axis to build the roof. Thinfilm, amorphous-silicon, triple-junction photovoltaic (PV) modules can be glued or laminated to the tray surface. The material produces electricity as well as performs its traditional weather-sealing function.

2.2.2.Vision GlassPV vision glass technology substitutes a thin-film, semi-transparent photovoltaic panel for the exterior glass face in a traditional double-pane glass window. Electric wires extend from the sides of each glass unit are connected to wires from other windows, building up the entire system. Many Universities install these types of PVs to efficiently operate their buildings and an adoption of their studies about the efficient, clean, inexpensive renewable energy.

2.2.2.1. Manchester Metropolitan University (MMU) Complete Solar Panel Project [1]MMU has invested almost half a million pounds in the installation of 400 photovoltaic (PV) panels covering 524 square meters one of the largest solar arrays of any UK university. The shiny PV panels have been successfully installed on the roof of MMU's Student Union. The conversion of sunlight to electricity by the cells will generate 40,900 kWh of energy per year enough power to light 7,200,100-watt light bulbs, power 960 student laptops, boil 40 kettles or supply electricity to 10 houses.


5

Chapter 2

Literature Review

Figure 2.1: MMU solar roof

2.2.2.2. University of Wisconsin-Green Bay [2]It integrates two Building Integrated Photovoltaic (BIPV) sections with separate photovoltaic (PV) technologies. One is Standing Seam Metal roofing that is used commercially, available roofing product and used commonly throughout Wisconsin. The other section incorporates a thin-film BIPV vision glass product. In total, about 4,300 square feet of (BIPV) material were installed, which will generate approximately 27,500 kWh annually.

2.2.3. MITs Solar Concentrator Window [3] [4]MIT engineers introduced a new approach to harnessing the sun's energy that could use sunlight to efficiently help power buildings. Light is collected over a large area (like a window) and gathered, or concentrated, at the edges. As a result, rather than covering a roof with expensive photovoltaic, the cells will only need to be around the edges of a flat glass pane. In addition, the focused light increases the electrical power obtained from each solar cell by a factor of over 40, without the need for solar tracking. That, in turn, would substantially reduce the cost of solar electricity. The MIT solar concentrator involves a mixture of two or more dyes that is essentially painted onto a pane of glass or plastic as shown in Figure 2.2. The dyes work together to absorb light across a range of wavelengths, which is then re-emitted at a different wavelength and transported across the pane to waiting solar cells at the edges.


6

Chapter 2

Literature Review

Figure 2.2: Organic solar concentrators collect and focus different colors of sunlight. Solar cells can be attached to the edges of the plates. By collecting light over their full surface and concentrating it at their edges, these devices reduce the required area of solar cells and consequently, the cost of solar power. Stacking multiple concentrators allows the optimization of solar cells at each wavelength, increasing the overall power output.

2.3. ElectrolysisWater electrolysis is essentially a conventional electrolysis process constantly under development. Other industrial electrolysis processes may include the electrolysis of Al2O3 for pure aluminum production and electroplating of iron surfaces. Applications of water electrolysis may include:

2.3.1.Sea Water (Brine) ElectrolysisA) NaOH and Cl2 production: for many industrial purposes. B) H2 production: About 4% of H2 gas produced worldwide is created by electrolysis. The majority of this hydrogen produced through sea water (Brine water) electrolysis where it is a side product in the production of chlorine.2 NaCl + 2 H 2O Cl 2 + H 2 + 2 NaOH

The hydrogen produced from this process is either burned, used for the production of specialty chemicals or various other small scale applications and of course for fuel cells. [5] Bayer Technology Services [6], Chlorine Engineers corp., Ltd. [7] and Han Su Technical Service Co., Ltd. [8] are examples of the companies using this technology.


7

Chapter 2

Literature Review

2.4. Fuel CellsIn the 21st century, fuel cells have been at the forefront of cutting edge science, with many people now viewing them as the only alternative to fossil fuels for generating power. Fuel cell vehicles can reduce emissions to zero if the hydrogen is produced from renewable electricity, which greatly improves local air quality. They also significantly reduce noise pollution as well. The numerous applications of fuel cells may include:

2.4.1. Stationary SystemsMore than 2500 fuel cell systems have been installed all over the world: In hospitals, nursing homes, hotels, office buildings, schools, utility power plants. They are either connected to the electric grid to provide supplemental power and backup assurance for critical areas, or installed as a grid-independent generator for on-site service in areas that are inaccessible by power lines.[9] In Europe, there is a great direction towards the Fuel Cell and Hydrogen technologies to the domestic stationary market, in the form of Combined Heating and Power (CHP) systems due to its benefits of high efficiency (approximately 85%) and low pollution (Chemical and Acoustic).

2.4.2. Transportation (Automotives)2.4.2.1. CarsAll the major automotive manufacturers have a fuel cell vehicle either in development or in testing right now and several have begun leasing and testing in larger quantities. Commercialization is a little further down the line (some automakers say 2012, others later), but every demonstration helps bring that date closer.[9] As an example of the demonstrated cars: BMW (series 7-745 h-Sedan): showed in 2000 with (UTC PEM FC 5 KW) ICE. Daihatsu (MOVE FCV-K II): showed in 2001 with (Toyota PEM FC 30KW)/battery hybrid engine. Daimler (A-Class F-Cell): showed in 2002 with (Ballard Mark 9000 series PEM FC 85KW)/battery hybrid Ford Motor Company (Explorer): showed in 2006 with (Ballard PEM FC 60KW)/battery hybrid engine. Honda (FCX Clarity): showed in 2007 with (Honda PEM FC 100KW) Engine.[11]


8

Chapter 2

Literature Review

2.4.2.2. BusesOver the last four years, more than 50 fuel cell buses have been demonstrated in North and South America, Europe, Asia and Australia [9] and manufactured by Honda, DaimlerChrysler, Toyota and Ballard power systems. [12]

2.4.2.3. Scooters (Small Motor Cycles)In spite of their small size, many scooters are pollution powerhouses especially those with two-stroke engines. This is a great application for fuel cells. The most outstanding models are MOJITO FC Scooter (known as Habana in Europe) which was produced by Manhattan Scientifics and Aprilia in 2007 but the production was stopped. Another one is Suzuki Burgman Fuel Cell Scooter which is manufactured by Intelligent Energy in partnership with Suzuki and announced in 2009. [13][14]

2.4.2.4. OthersLike airplanes, marine and trains. They are under development to be operated by the fuel cells which give better efficiency, durability and lifetime than the batteries. Boeing is developing its first fuel cell plane.

2.4.3.Portable Micro-PowerLike mobiles and laptops, companies have already demonstrated fuel cells that can power cell phones for 30 days without recharging and laptops for 20 hours. These miniature fuel cells generally run on methanol, an inexpensive wood alcohol. [9] Toshiba has developed a mobile charger Dynario. It has a methanol fueled fuel cell which causes a reaction between H2 in methanol and O2 to produce the charging electricity. [13]

Figure 2.3: Toshiba Dynario mobile charger [16][ 17]

In the beginning of 2004, Japanese electronics company NEC has shown the prototype of a laptop with built-in fuel cell, claiming the prototype has 10 hours life, extending the life of the traditional battery powered laptop by up to 50%. [14] In 2006 Toshiba and Samsung has shown off their fuel cell laptops.[16][17][18][19]


9

Chapter 2

Literature Review

Figure 2.4: From left NEC, Toshiba, Samsung laptops [10][16]

2.5. Commercial Applications2.5.1. Home Energy StationIn 2003, Honda has established an experimental Home Energy Station (HES) that generates hydrogen from natural gas for use in fuel cell vehicles and can also supply electricity and hot water to the home. Part of ongoing research by Honda into hydrogen energy sources, the new system can currently produce enough hydrogen to refill the tank of a Honda FCX hydrogen fuel cell vehicle taking just a few minutes once a day. Honda is also applying newly developed solar panel technology to its hydrogen-refueling R&D by using the energy generated by the panels mounted on the refueling station to improve its overall efficiency other than Home Energy Station (HES III) which is using natural gas. [20]

Figure 2.5: Home Energy Station (HES III)


10

Chapter 2

Literature Review

2.6. Experimental Applications2.6.1. Dr FuelCell Science Kit [21]

Figure 2.6: Dr Fuel cell science kit

2.6.1.1. OverviewThe Dr FuelCell Science Kit, shown in Figure 2.6, is an extensive experiment set for the subject of renewable energies for students. The Dr FuelCell Science Kit reproduces a complete solar hydrogen energy cycle. It makes it possible to approach the subject of renewable energies both as a complete cycle and at the level of the single technologies of photovoltaics and the fuel cell.

2.6.1.2. ComponentsThe components of the Dr FuelCell Science Kit can be used in various ways for instruction. Solar panel The 5-cell photovoltaic module is used for experiments in solar energy and for generating electric energy for the hydrogen generator. The practical base facilitates alignment to the light source. The electrolyser separates water into hydrogen and oxygen. It is operated with distilled water and requires no caustic solutions or acids. The integrated graduated hydrogen storage cylinders visualize the classic hydrogen separation experiment, as in the Hoffmann apparatus.11

Electrolyser


Chapter 2

Literature Review

The fuel cell generates electrical energy from hydrogen and oxygen. It is based on PEM technology, which is the most widespread technology used in the development of fuel cell applications, e.g. for motor vehicles or stationary power supply systems. Load The convenient and compact load measurement box is used measurement for recording data during experiments. Integrated consumers, such as a motor, a lamp and 7 selectable resistors, enable box numerous experiments, e.g. recording characteristic curves, or current and voltage. Take-apart fuel The take-apart fuel cell makes it possible to examine the functions and the design of a fuel cell in detail. A plug-in cell resistor, an electrode with reduced catalyst quantity and an air panel for air instead of oxygen operation enable in-depth experiments. Methanol fuel The methanol fuel cell uses methanol instead of hydrogen to generate electrical energy. This makes it possible to conduct cell more extensive experiments. The package includes storage cylinders for storage of the methanol solutions. Fuel cell

2.6.1.3. Technical DetailsDr FuelCell Science Kit Complete Dimensions (W x H x D):430 x 150 x 310 mm Weight: ca. 10.1 kg Solar panel Dimensions (W x H x D): 80 x 130 x 52 mm Voltage: 2.0 V Current: 180 mA Output: 0.36 W Electrolyser Dimensions (W x H x D): 80 x 195 x 85 mm Storage volume for hydrogen and oxygen: 10 ml each Operating voltage: 1.4 ... 1.8 V Electric current: max. 500 mA Hydrogen production: max. 3.5 ml / min (at 500 mA) Fuel cell Dimensions (W x H x D): 65 x 85 x 38 mmSolar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 12

Chapter 2

Literature Review

Rated output: 0.25 W Voltage: 0.4 ... 0.9 V Current: max. 1000 mA Load measurement box Dimensions (W x H x D): 190 x 110 x 60 mm Ammeter: 0 ... 2 A Voltmeter: 0 ... 20 V DC Measured resistance (in ohm): 1, 3, 5, 10, 50, 100, 200, open and short circuit Take-apart fuel Dimensions (W x H x D): 85 x 65 x 65 mm cell Rated output for oxygen mode: 0.3 W Voltage: 0.4 ... 0.9 V Current in oxygen mode: max. 1500 mA Current in air mode: max. 800 mA Methanol fuel cell Dimensions (W x H x D): 65 x 85 x 34 mm Rated output: 0.1 W (with 1 M methanol solution) Voltage: 0.1 ... 0.6 V Current: max. 100 mA Dr FuelCell Professional manufactured by Heliocentris Inc. www.heliocentris.com


13

Chapter 2

Literature Review

2.6.2. Dr FuelCell Model Car [22]

Figure 2.7: Dr Fuel cell model Car

2.6.2.1. OverviewModel Car with reversible Fuel Cell The Dr FuelCell Model Car integrates the subject of renewable energies in the instruction for the lower secondary level in an uncomplicated manner. Hands-on teaching of renewable energies The Dr FuelCell Model Car can be operated with energy from a fuel cell or a solar panel. A reversible fuel cell makes it possible to generate and store hydrogen wherever it is needed. Practical experiments help students easily understand the relationships between energy conversion, storage and consumption. Extensive features The package includes a reversible fuel cell, which functions both as a hydrogen generator and fuel cell. The fuel cell uses the energy supplied by the solar panel or the hand generator to separate water into oxygen and hydrogen. In fuel cell mode, the stored hydrogen is converted into electric power to operate the car. The load measurement box makes it possible to measure the current and voltage.


14

Chapter 2

Literature Review

Time-tested quality Developed for daily use in the classroom, the model car is user-friendly and features a flexible and robust design, making it suitable for both group and individual instruction.

2.6.2.2. ComponentsThe single components of the Dr FuelCell Model Car can be used in various ways for instruction. Solar panel The 5-cell photovoltaic module is used for experiments in solar energy and for generating electric energy for hydrogen production. The practical base facilitates alignment to the light source. The module can easily be mounted on the car chassis to make a solar vehicle. This component is a fuel cell and hydrogen generator in one. It is operated with distilled water and requires no caustic solutions or acids. The generated hydrogen is stored in integrated gas storage cylinders, safely and directly. The car chassis is designed both for fuel cell operation and solar operation. A single click and two cable connectors are all you need to make the switch. The front axis is steerable and lockable, so the car chassis can also be used where space is limited. The load measurement box for recording data is used for advanced experiments. Integrated consumers, such as a motor, a lamp and 7 selectable resistors, enable numerous experiments, e.g. recording characteristic curves, or current and voltage. The high-quality hand generator, which simulates wind power, is an alternative to the solar panel. Muscle power is used to generate electrical energy for the separation of water in the reversible fuel cell.

Reversible fuel cell with integrated gas storage cylinders Car chassis

Load measurement box Hand generator


15

Chapter 2

Literature Review

2.6.2.3. Technical DetailsDr FuelCell Model Car Complete

Erection

Dimensions (W x H x D): 345 x 160 x 280 mm Weight: ca. 2.9 kg Language versions: German, English, French, Spanish, Italian, Turkish, Japanese, Korean and Arabic Dimensions (W x H x D): 80 x 130 x 52 mm Voltage: 2 V Current: 180 mA Output: 0.36 W Dimensions (W x H x D): 80 x 80 x 70 mm Operating voltage: 0.5 ... 0.9 V DC Rated output: 0.25 W Operating current: 0 ... 500 mA Hydrogen production: max. 3.5 ml / min Dimensions (L x W x H): 195 x 110 x 50 mm Operating voltage of motor: 0.5 ... 3.0 V Hydrogen consumption: 3 ... 5 ml / min Running time with full gas storage cylinders: 3 ... 5 min Dimensions (W x H x D): 190 x 110 x 60 mm Ammeter: 0 ... 2 A Voltmeter: 0 ... 20 V DC Dimensions (W x H x D): 55 x 137 x 55 mm No-load voltage: 2.1 V Typical operating voltage with electrolyser: ca. 1.7 V

Solar panel

Reversible fuel cell

Car chassis electric motor

with

Load box:

measurement

Hand generator

Dr FuelCell Model Car manufactured by Heliocentris Inc. www.heliocentris.com


16

Chapter 2

Literature Review

2.6.3. Fuel Cell Kit, Green Utility House [23]

Figure 2.8: Fuel Cell Kit, Green Utility House

With this fuel cell kit, you can build your own experimental green utility house and install wind energy, solar energy, and fuel cell home power generator. Fuel Cell Kit: shows energy conversion and storage demonstrates the application of renewable and non-pollutant energies in daily lives teaches electrochemical experiments and new technology appreciation lets us discover principles of fuel cells, wind energy, solar energy, electrolyser, and hybrid systems Solar and wind energy are not reliable sources of energy. During nighttime or at times of reduced or no sunlight or wind, these systems are not able to generate electricity. Fuel Cell Kit, Green Utility House shows how this problem can be overcome if the extra electricity produced by solar cells during sunny days or by wind turbines during windy days can be stored (Fuel Cell Kit green utility house can only store solar energy not wind energy). In this fuel cell kit, the electrolyser is able to use the extra electricity to convert water into hydrogen and oxygen gases that can be stored. During the night time or at times of a reduced or absent sunlight and wind, the fuel cells consume stored hydrogen to generate electricity. In the hybrid system, such a Fuel Cell Kit Green Utility House fuel cells and hydrogen technology cover the short-coming of solar and wind energy to provide continuous, reliable, and independent power supplies.


17

Chapter 2

Literature Review

These educational kits are all about energy conversions. When light is emitted and reaches the solar cells (1), the cells convert the energy of light to electricity (electric energy). The electrolyser (2) then uses this electricity, to decompose the water to produce hydrogen and oxygen gas. These gas products enter a fuel cell (3) and within an electrochemical reaction, water and electricity are produced. As the endproduct of the 2 fuel cell, electric energy will power the electric motor (4). In the Green Utility House and Solar House products when air pushes the wind turbine blade (5), the electric shaft of the electric motor rotates. The electric motor acts as a generator and converts the kinetic energy of wind to electricity. The generated electricity then will be used in the ceiling fan (4). Fuel Cell Kit, Green Utility House manufactured by Hydrogen and Fuel Cell Inc. www.h-fc.com

2.6.4.Fuel Cell Car Science Kit [24]

Figure 2.9: Fuel cell car science kit


18

Chapter 2

Literature Review

Fuel Cell Car Science Kit uses a reversible PEM fuel cell that combines electrolysis and power conversion into one single device. Watch as oxygen and hydrogen gases are formed in two transparent water containers. The car steers independently of the user once in operation: when the car hits a barrier, it will automatically find its way by reversing away 90 degrees. Fuel Cell Car Science Kit manufactured by Horizon Fuel Cell Inc. www.horizonfuelcell.com

2.7. ConclusionOur project essentially aims to build a Solar-Hydrogen Fuel Cell Educational Stand that demonstrates the idea of Home Refueling Station or Solar-Hydrogen House which is the major technique required for Solar Energy continuous availability. In addition our educational stand makes student aware of establishing an educational stand that students in the mechanical power department will learn from, understanding the operation of each device and studying its performance and characteristics as an individual device and when working as a Home Refueling Station and building the ability of measuring different quantities and analyzing the results by using digital measuring devices and computer programs.

In one word we can say that: Solar-Hydrogen House: No More Power BillsEver


19

Chapter 2

Literature Review

2.8. References[1] http://www.mmu.ac.uk/news/articles/1098/ [2] http://www.p3xcel.com/project12.html [3] http://web.mit.edu/newsoffice/2008/solarcells-0710.html [4] http://www.domain-b.com/technology/20080711_window.html [5] http://en.wikipedia.org/wiki/Electrolysis [6] http://www.bayertechnology.com/en/products/chlorine-electrolysis/chlorine-electrolysis/is-your-gain.html [7] http://www.chlorine-eng.co.jp/en/product/electrolysis/brine-electrolysis.html [8] http://www.tradekorea.com/product-detail/P00157657/Brine_treatment_system.html [9] http://www.fuelcells.org/basics/apps.html [10] http://www.engadget.com/2006/06/01/toshiba-shows-off-latest-laptop-fuel-cell-prototype/ [11] http://www.fuelcells.org/info/charts/carchart.pdf [12] http://www.fuelcells.org/info/charts/buses.pdf [13] http://www.varsitycycle.com/aprilia_mojito_retro.shtml [14] http://www.reuters.com/article/idUSTRE6123FY20100203 [15] http://www.crunchgear.com/2009/10/22/dynario-toshiba-finally-commercializes-fuel-cell-for-mobile-devices/ [16] http://www.gizmag.com/go/3354/ [18] http://www.engadget.com/2006/06/01/toshiba-shows-off-latest-laptop-fuel-cell-prototype/ [19] http://www.gizmag.com/go/6666/ [20] http://automobiles.honda.com/fcx-clarity/home-energy-station.aspx [21] http://www.heliocentris.com/en/customers/education/products/science-education/dr-fuelcell-science-kit.html [22] http://www.heliocentris.com/en/customers/education/products/science-education/dr-fuelcell-model-car.html [23] http://www.h-fc.com/ [24] http://www.horizonfuelcell.com/education_kits.htm


20

Chapter 3

Preparation

Chapter 3

PREPARATION


21

Chapter 3

Preparation

In order to convert the idea into reality, a complete design of the system needed to be studied and implied. We started brain storming to put the preliminary shape of the system. We agreed that in order to identify the required sizes of the different components, the required load should be first determined. The final load was the electric heater. We realized that electric heaters can have a wide range of sizes starting from 0.1W to whatever we can imagine. On the other hand, the sizes of each of the fuel cell, electrolyser and PV cells available commercially are limited. Thus, our mission was to identify commercially available electrolyser-fuel cell system that is compatible. The next step is to find the suitable PV size to supply the required voltage and current to the electrolyser. This is a summary of the available fuel cells and electrolysers at the time.

3.1. Electrolysers3.1.1. Esperanza (Heliocentris, www.heliocentris.com)We contacted Esperanza and also Heliocentris and they both told us the same information. They produce hydrogen generators which work at 230V, produce large quantity (15-60 liters per hour). Thats very professional while we are looking for something more educational. So, we started to contact Fuel Cell Store (www.fuelcellstore.com) for the electrolyser and the fuel cell.

3.1.2. The Fuel Cell Store ElectrolysersAmong a variety of electrolysers, we found two suitable ones, which are:

3.1.2.1. AS1 Electrolyser [1][2]The AS1 Stack on Electrolyser is an Alkaline Electrolyser capable of producing 0.25 Liters of hydrogen a minute at a fraction of the cost for comparable PEM Electrolysers. Using an alkaline chemistry with a 30% KOH electrolyte the AS1 can produce 360 Liters of hydrogen for only $.36 and the upfront cost is 3% the cost of a PEM electrolyser. The smallest unit can generate 15 Liters per hour but the system is stackable to suit any system size and operating requirements. Gas purities are greater than 99.6% and with additional catalytic recombiner purities over 99.9999% hydrogen can be achieved. It has a built-in ECM (Electronic Control Module) that fully automates and maintains the optimum level of water to the Electrolyser and the Double Bubbler. The hydrogen and oxygen can be collected safely in a low pressure tank for use later. Great for powering an alkaline or PEM fuel cell to generate electricity that can power electrical appliances even the entire home or hydrogen stove for cooking. A 90 watt Solar Panel will give ample power to run one electrolyser to make an unlimited amount of hydrogen.


22

Chapter 3

Preparation

Electrolyser Dimensions: Electrodes: Electolyte: No. of cells: Voltage: Current: Hydrogen Output: Oxygen Output: Pressure: 3 x 4 x 7.5in Nickel Plated 316SS 30% KOH 5 (2.5 volts/ cell) 12 volts 7 Amps. 15 liters/hr. (30 liters/hr @ 15 Amps.) = (500 ml/ min) 7.5 liters/hr. (15 liters/hr @ 15 Amps.) Non-Pressurized

Hydrogen Purity: 99.6%** Recirculator: Double Tube Material: Height: 1.5in. Diameter 304 SS (or ABS) 11in.

Electronic Control Module: Epoxy encased integrated with electrolyser body Start up tubing purge cycle Automatic sensing water level Automatic water refill.


23

Chapter 3

Preparation

3.1.2.2. AS15 Electrolyser [3] (LAB H2 SUPPLY[4])Alkaline type with higher efficiency: up to 70% and generates more H2 gas compared to PEM electrolyser for the same amount of electric current. Pressure up to 30 psi: meets most fuel cell requirements. Four minute auto purge at startup, safety pressure relief at 40 psi. 99.9% Purity H2 gas with optional O2 collection capability 7 Amps produces 15 liters of H2 per hour: Maximum allowable current of 15 Amps makes 30 liters of Hydrogen per hour.

3.2. Fuel CellsWe contacted fuel cell store about two types of fuel cell:

3.2.1. Convection fuel cell stack3.2.1.1. 30W 6.5V, 36W 6V Fuel Cell Stack [5]Product Overview The 30-36 W Convection fuel cell stack is a 10 cell stack that does not require external humidification or pressurization. Gold-plated current collectors ensure that this stack achieves maximum performance for precision experiments. The stack comes complete with instruction manual, I/R plot, shade for assisting the convection air flow and a six-month warranty. Possible sources of hydrogen for the 30-36 W convection fuel cell stack include electrolysers (PEM- and alkaline technologies), gas bottles, metal hydride tanks and hydrogen from chemical reactions. In order to use the fuel cell in both operating modes a control unit is required The control unit for this fuel cell performs three functions. It includes a regulator to control the inlet pressure to the stack. It monitors the temperature and operates the cooling fans as necessary and it also regulates the purging cycle for hydrogen in the dead-ended mode of operation of the fuel cell. The control unit regulates the back pressure to make sure that too much pressure does not build up inside the stack. It is a dead ended fuel cell and over pressure can damage the membranes. These stacks are "Air-Breathing", Convection style stacks with self-humidified Membrane Electrode Assemblies. Hydrogen can be kept dead-ended and water is removed continuously from the stack. The maximum operating temperature can be from 65-70 C and at pressures from 1 to 10 psi. No special


24

Chapter 3

Preparation

startup procedure or forced flow of air is required; however much higher power densities can be obtained utilizing forced air flow.

Technical Specifications Number of cells Membrane Area Power Reactant Temperature Pressure Humidification Cooling Weight Dimension Hydrogen Flow Rate Type of fuel cell Start up time Efficiency of stack 10 25 cm2 30W at 6.5V,36W at 6V H2/air Ambient-70C 0-2 psi (hydrogen) Self-humidified Air (cooling fans supplied and attached to the side) 3.5 pounds 10 cm x 8.2 cm x 11 cm (LxWxH) About .35 Liters per minute at full power PEM Instantaneous, load following capability 50% at full power


25

Chapter 3

Preparation

3.2.1.2. 20W 13V, 25-30W 12V Fuel Cell [6]Has the same information for 30W 6.5V, 36W 6V Fuel Cell Stack Technical Specifications

Number of cells Membrane Area Power Reactant Temperature Pressure Humidification Cooling Weight Dimension Type of fuel cell Start up time Efficiency of stack

20 10 cm2 20W at 13V, 25-30W at 12V H2/air Ambient-70C 0-2 psi (hydrogen) Self-humidified Air (cooling fans supplied and attached to side) 2.25 pounds 14 cm x 5.7 cm x 8.8 cm (LxWxH) PEM Instantaneous, load following capability 50% at full power

3.2.2. H-Series Fuel Cells3.2.2.1. H-20 (20W Fuel Cell Stack) [7][8]Product Overview The H-series Polymer Electrolyte Membrane (PEM) fuel cells, design by Horizon, are semi-integrated, efficient, reliable systems that minimize the use of peripherals. As such, they are the most compact and lightweight air-cooled, self-humidified fuel Cells around the world. The fans and purge value on the H-20 do not require an additional power source they are run by the fuel cell. H-20 includes the following itemsSolar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 26

Chapter 3

Preparation

*Electronic and Gas Connections *Miniature electronic valve: This is the purging value to purge hydrogen in the event of overpressure of the fuel cell *Control electronics: To regulate the purge value and fans *Integrated fan and casing: The fan is for cooling the casing is to protect the fuel cell *Low pressure protection: There is no low pressure protection on the fuel cell, the high pressure protection would start around 6 psi. Technical Specifications Type of Fuel Cell Number of cells Rated power Performance Purging Valve Voltage Blower Voltage Reactants External temperature Stack operation temperature Composition Hydrogen pressure Humidification Cooling Weight (with fan and casing) Dimensions Hydrogen flow rate Start up time Stack efficiency PEM 11 20W 6.6V @ 3A 6V 5V Hydrogen and air 5-40C 55C 99.999% Dry H2 2.9-4 PSI Self humidified Air (integrated cooling fan) 230g 7.6cm x 5.6cm x 4.7cm 280ml/min of hydrogen at maximum power Immediate 45% at maximum power


27

Chapter 3

Preparation

3.2.2.2. H-30 (30W Fuel Cell Stack) [9][10]Product Overview The H-series Polymer Electrolyte Membrane (PEM) fuel cells design by Horizon are semi-integrated, efficient, reliable systems that minimize the use of peripherals. As such, they are the most compact and lightweight air-cooled, self-humidified fuel Cells around the world. The fans and purge value on the H-30 do not require an additional power source they are run by the fuel cell. Details H-30 includes the following items *Electronic and Gas Connections *Miniature electronic valve This is the purging value to purge hydrogen in the event of overpressure of the fuel cell *Control electronics To regulate the purge value and fans *Integrated fan and casing The fan is for cooling the casing is to protect the fuel cell *Low pressure protection There is no low pressure protection on the fuel cell, the high pressure protection would start around 6 PSI

Technical Specifications Type of Fuel Cell Number of cells Rated power Performance Purging Valve Voltage Blower Voltage Reactants PEM 12 30W [email protected] 6V 5V Hydrogen and air 28


Chapter 3

Preparation

External temperature Stack operation temperature Composition Hydrogen pressure Humidification Cooling Weight (with fan and casing) Dimensions Hydrogen flow rate Start up time Stack efficiency

5-40C 55C 99.999% Dry H2 4.3-5.8 PSI Self humidified Air (integrated cooling fan) 235g 8.0cm x 5.4cm x 4.6cm 420 ml/min of hydrogen at maximum power Immediate 45% at maximum power

3.3. Further DetailsThe two types of the fuel cells are dead-ended. That means there is no hydrogen outlet on these cells; the hydrogen put into the cell is all used in the reaction and output as water and heat. The H-20 and H-30 fuel cells require a small amount of pressure for operation and would not work with the AS1 electrolyser. In order to use the electrolyser to directly fuel the H-20 or H-30 we will need a low pressure storage cylinder to capture the excess gas produced. The AS15 system produces pressurized gas at 30 PSI and this requires regulation before being fed into the fuel cell. It must also be allowed to produce hydrogen and store it if not being used directly. This will keep the cell safe from over pressurization and keep the electrolyser producing gas without venting the excess hydrogen into the air. The cathode side of the fuel cell where the water will be generated is open to air. Any liquid water formed would fall out the bottom of the cell. The heat is removed by the attached fans which operate to cool the cell. There is no blower on the H-30. The Fans can be considered a blower but are listed as fans. Both of these fuel cells are a "convection" type. They both use the oxygen from the air in the environment and do not require a pure oxygen flow. The fans do serve to both remove heat and keep a constant flow of air over the cathode side of the fuel cells. Neither of these cells have the capability to use a pure oxygen flow for the operation of the fuel cell.Solar Hydrogen Fuel Cell Electric Heater Educational Stand - Cairo University | 2009-2010 29

Chapter 3

Preparation

The output of the fuel cell connections are 8 gauge wires which can be connected in any way we choose (no special electrical cables). Characteristic curve is not available for the convection stack fuel cells but is contained in the user manual for the H-30 fuel cell. Current vs. hydrogen production curve for the AS15 electrolyser: There is a linear increase between the hydrogen product and current increase of the AS15 from 7 amps up to 15 amps compared to a production increase of 15 l/hr to 30 l/hr. The pressurized versions of the AS15 include holding tanks which will allow us to properly store excess hydrogen during a continuous operation of the electrolyser powering the fuel cell. We would need to maintain the proper voltage so as not to fill up the holding tanks but they will provide enough storage to make the direct operation of a fuel cell possible. The small internal storage of the pressurized AS15 is at 30 psi. The internal storage on the AS15 can be stated to have 0 storage capacity. This is an internal reservoir for pressurizing the hydrogen for release. Hydrogen cannot be stored inside the electrolyser for a sustained period of time. Other questions and answers * What is the preferred electrolyser which will work with (30W 6.5V, 36W 6V Fuel Cell Stack) and (20W 13V, 25-30W 12V Fuel Cell Stack)? The AS15 is the preferred electrolyser for all of our smaller fuel cell stacks. It will work the same with these cells as with the H-20 and H-30. * If the electrolyser produced excess hydrogen over the required to operate the fuel cell and no storage, what will happen? If the fuel cell is dead ended and the electrolyser is constantly producing gas with no outlet it will put a hole in the membranes in order for the rising pressure to escape. This would permanently damage the fuel cell and make for a very costly repair. If there is an outlet for the hydrogen to escape then it will instead release the pressure through that outlet, this is the function of the hydrogen purge valve on the H-20 and H-30 fuel cells. * What will happen for the remaining rates produced from the electrolysers & not used by fuel cell? In order to use the electrolyser to directly fuel the H-20 or H-30 you will need a low pressure storage cylinder to capture the excess gas produced. The AS15 system produces pressurized gas at 30 PSI and this need to be regulated before being fed into the fuel cell. It must also be allowed to produce hydrogen


30

Chapter 3

Preparation

and store it if not being used directly. This will keep the cell safe from over pressurization and keep the electrolyser producing gas without venting the excess hydrogen into the air. * What is the difference between the convection fuel cell stack and the H-series fuel cell? Very little is different between these cells. They all operate as convection stacks, not requiring pure oxygen. They operate at very similar hydrogen pressures and use very similar amounts of hydrogen. The H-series cells are manufactured by a large company with a high production volume which allows them to lower the cost, which is the biggest difference between the different stacks.

3.4. Our ChoiceAfter requesting all the information we needed, we decided on the 30W Fuel cell and the AS15 electrolyser for the following reasons: 1. A 30W Fuel cell gives enough measurable power 2. Their prices are suitable for our budget 3. They are the most compatible couple in the choices we had with the pressurization problem being solved as well as the hydrogen purity

3.5. Steps towards PurchasingAfter we decided on the electrolyser-fuel cell couple we immediately put a company in charge in contacting and purchasing the components. The process of communication was first drawing some success and they promised the fuel cell will be shipped from the states within 2 weeks while the electrolyser will be shipped after a month due to slow fabrication process. Figure 3.1 shows the contract.


31

Chapter 3

Preparation

Figure 3.1: Purchase Invoice


32

Chapter 3

Preparation

During the time we waited, we began our search for the PV. This was much easier as we have local producers. We visited all present producers, collected information and decided on a 200W solar panel as well as the shape of our bench which was a house. The details of the bench shape are in chapter 8. However, the month passed and none of the components was delivered. We began to be disappointed. We started contacting the company again to contact them and we figured out that for some reason they stopped producing the electrolyser. That happened after two months from purchasing. We tried to search for other companies in countries of far Asia and Europe but we didnt find something educational and we had no time to waste, so we had to take a quick decision. In the USA they say if you cant shoot the moon, shoot the stars, so we had no choice but to work on a smaller scale. The new system was 1.7W Fuel cells and we had a big challenge to design a suitable heater, which we did. Perhaps the project we had in mind did not exactly come true, but at least we delivered our aim of demonstrating the new system which will change the world to junior and senior students in our department, no matter how small it is.


33

Chapter 3

Preparation

3.6. References[1]. http://fuelcellstore.com/en/pc/viewPrd.asp?idcategory=0&idproduct=1405, [2]. http://peoplesnewenergy.com/ [3]. http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=39&idproduct=1412 [4]. http://peoplesnewenergy.com/ [5]. http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=46&idproduct=369#details [6]. http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=46&idproduct=1389 [7]. http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=46&idproduct=1104 [8]. http://www.horizonfuelcell.com/fuel_cell_stacks.htm [9]. http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=46&idproduct=1105 [10]. http://www.horizonfuelcell.com/fuel_cell_stacks.htm


34

Chapter 4, Part 1

Solar Cell

Chapter 4

COMPONENTS


35

Chapter 4: Part 1

Solar Cell

Chapter 4: Part 1

SOLAR CELL


36

Chapter 4: Part 1

Solar Cell

4.1.1. Brief History [16]Solar energy was never a new invention, however converting this energy to mechanical or electrical energy was the invention. Nature of materials that conve

Documents

Solar Hydrogen Fuel Cell Water Heater (Educational Stand)