06213 – Hydrogen Fuel Cell Test Station

Preliminary Design Review

February 24th, 2006

Group Members• Team Leader: Chad Byler (ME)

• Mechanical Press & Fuel Flow:Dan Upton (ME), Brian Holzberger (ME), &

Sean Ashman (ME)

• Electrical Sensors & Power Supply:Dennis Farley (EE) & Steve Yang (EE)

• Data Acquisition & Software: Shan Hu (CE)

• Process and Safety: Corey Reynolds (ISE)

Project Mentor: Dr. Bailey(ME)

Project Sponsor

• Nanopower Research Laboratory

– Funding• Dr. Rafaelle – Department of Physics at RIT

– Customer Contact• Cory Cress – PhD student in Microsystems

http://www.rit.edu/~physics/Research/nanopower.shtml

Subsystem Topics

• Layering of Fuel Cell• Mechanical Assembly Process• Heating of the Fuel Cell• Humidification of gas• Exhaust/Back Pressure Control• Electrical Sensors and Power Supply• Heating elements• Layout of program logic• Data Acquisition• Budget

But First…

Cathode Reactions:

1/2 O2 + 2e- O-2ion

Porous gas diffusion layer Porous gas diffusion layer2e- 2e-

Reaction Products(H2O only)

Air/O2H2

O2

Catalyst LayersActive Material:Platinum or Platinum/Ruthenium

Thin solid hydrated Membrane as an Electrolyte

Anode Reactions:

H2 2H+ + 2e-

H+ion

proton

2H+ + O-2ion H2O

PEM = Low temperature (80oC) hydrogen fuel cell with polymer electrolyte and precious metal electrodes

Fuel Cell Operation

Cathode = gas diffusion layer + catalyst layer

Anode = gas diffusion layer + catalyst layer

Location - Fuel Cell Assembly

Electrode Plate

–Raised center portion to ensure maximum pressure of electrode with nano-tube catalyst.–Three different sizes for reaction area.

Fuel Cell Assembly

Nano-tube catalyst

PEM

Fuel Cell Stack

Location - Fuel Cell Assembly

Mechanical Assembly

• Ease of Operation•Backing Plate rotates to allow assembly on horizontal surface.•Pegs hold fuel cell assembly in place until it can be compressed.

• Repeatability•Use of power screw in combination with a pressure sensor or a torque wrench will allow for a repeatable mechanical pressure applied to the fuel cell.•The use of the mechanical assembly gives the ability to encapsulate the fuel cell and regulate the temperature.

Mechanical Assembly Animation

Power Screw CalculationsInternal Pressure 120 psi  

Surface Area 2.64 in^2  

Max Force 316.8 lb  

   

tan() must be less than the coefficient of friction in order to be postitive locking

Screw Type: 1/2" - 10  

Lead L= 0.1 in  

Root Dia. Dr= 0.45 in  

   

tan()=L/(*Dr)        

tan()= 0.071      

= 0.3 Coefficient of friction steel to steel  

tan() < , therefore the screw is self locking  

   

T=F*Dr/2*((L+**Dr)/(*Dr-*L)  

   

T = 26.999 Lb/in  

T = 2.25 Lb/ft            

Location - Fuel Cell Heating

Fuel Cell Heating

Steady-State Temperature Distribution without Insulation (O2 side)

-Shows need for cell Insulation

-With insulation all cell components reach 80°C at S.S.

Location - Humidification

Gas Humidification Method

•H2 or O2 inlet in base

•Bubble up through water

•Temperature of water controls the humidity of exit gas

•Resistive heater used to heat water

•Water temperature monitored to ensure safe heating

Expansion Valve

Contains:• Pressure Sensor• Humidity Sensor• Temperature Sensor

Pros:• Interchangeable• Non-Intrusive to flow

Location – Back Pressure

Exhaust/Pressure Regulation

• Constant Upstream Pressure

• Bleeds overpressure• Ability to dry PEM• Bubbles prove flow• Water seal provides

no upstream airflow

Overview Schematic

Important Sensor Parameters

• National Semiconductor LM34 Temperature Sensor:– Maximum Current Draw: 90μA– Maximum Output Current: 160μA– Maximum Output Voltage: 6V– Accuracy: 0.555°C– Operating range: -45°C to 150°C

• Honeywell HIH-3610 Humidity Sensor:– Maximum Current Draw: 200μA– Maximum Output Current: 100μA– Maximum Output Voltage: 3.9V– Accuracy: 2% Relative Humidity– Operating Range: 0 to 100% Relative Humidity in -40°C to 85°C

Important Sensor Parameters Cont.

• Honeywell ASDX100G24R Gas Pressure Sensor :– Maximum Current Draw: 10mA– Maximum Output Current: 2mA– Maximum Output Voltage: 5V– Accuracy: 2% of Operating range– Operating range: 0 to 100 PSI in 0°C to 85°C

• Honeywell TD4A Liquid Temperature Sensor:– Maximum Current Draw: 26.3mA– Maximum Output Current: 1mA– Maximum Output Voltage: 2.5V– Accuracy: 1°C– Operating Range: -40°C to 150°C

Worst Case Analysis

Maximum Current Draw:• For Heaters: 0.83A maximum per heater * 3 = 2.5A

maximum• For LM34 Temperature Sensors: 90μA * 3 = 270μA• For HIH-3610 Humidity Sensors: 200μA * 2 = 400μA• For ASDX100G24R Gas Pressure Sensor: 10mA * 2 =

20mA• For Underwater Temp Sensor: 26.3mA * 3 = 78.9mA

• Total Current Draw = 2.51056A

Heater Analysis

• 58200 Joules are needed to heat the water in our largest tank, 0.2317L, from 20°C to 80°C– Using an Omega CIR-3016 (100 Watt)

– Therefore, the longest time needed to heat the water is 9.7 minutes

min7.9sec60

min1sec*582

sec582100

sec)*58200(

W

W

Omega Immersion Cartridge Heater

• 150 Watt Heater

• Incoloy® Sheath - Efficient heat transfer - Sealed tip

- Corrosion resistant.

• Special Insulation - High dielectric strength - Faster heat-up time

• Small size - 1/2 inch diameter

Water Heating Source

Water Temperature Sensor

TD4A - Liquid Temperature Sensor

• RTD (resistance temperature detector) sensors

• Respond rapidly to temperature changes

• Accurate to ± 0.7 °C at 20 °C

• Temp. range: -40 °C to 150 °C (-40 °F to 302 °F)

• Supply Voltage/Current: 10Vdc, 1mA typ.

• Linear outputs.

Power Controllers

Power-IO Solid State Relays

• Surge protection

• DC control input: 4-32VDC

• Operating Voltage: 24-330V

• Max Load Current: 25A

• Affordable price (under $40)

Software Design Flowchart I Start

User input desired testing parameters (Temp/Humidity/Pressure/Duration)and the max pressure, max temperature should be allowed

Test Temperature sensor

Is temp sensor ok?Show error message!

Terminate the program!

End

Set up testing environments

Start testing?

All desired testing parameters are

satisfied?Show violation message!

Timer counts

End test?

Record testing results

Continue without adjustment?

N

Y

Y

Y

Y

Y

N

N

N

N

Software Design Flowchart IISet up testing environments

Heat H2 and O2

water tank

Exceed max water temp?

Show warning!

Desired gas humidity?

Y

N

End set up testing environments

DisplayGas

Temp(H2 and

O2)

Display water temperature

Display gas humidity (H2 and O2)

Desired temp?

Display PEMtemperature

N

Y

Y

N

Y

Desired gaspressure?

Adjust pressure of H2 and O2 gas

Display pressureof H2 and O2 gas line

Heat PEMwater tank

Exceed max water temp?

N

YN

Dangerouslevel?

ShutOff!

YN

Show warning!

Dangerouslevel?

ShutOff!

Y N

Exceed max gas pressure? Y

N Show warning!

Dangerouslevel?

ShutOff!

Y N

USB-1208LS + LabVIEW™ drivers     USB-based DAQ module ( $109.00 x 2 + $ 49.00)

•8 Single-Ended or 4 Differential Analog Inputs •12-bit (Diff.)/11-bit (SE) Resolution •Two 10-bit Analog Outputs •One 32-bit External Event Counter •16 Digital I/O Lines •External Trigger Input•Sample Rate 1.2KS/s

Design ProcessOriginal Project Objectives

1. Flow Systems

2. H2 & O2 Electrolysis and Delivery

3. Temperature Systems

4. Pressure Systems

5. Humidity Systems

6. Mechanical Assembly (Optional)

Current Project Objectives

1. Mechanical Assembly

2. H2 & O2 Creation and Delivery

3. Temperature Systems

4. Pressure Systems

5. Humidity Systems

Flow System

Electrolysis System

H2 & O2 Tanks

Flow System

Major Project Scope Changes

Scope Change Impact

Research

Concept Generation

Concept Selection

Feasibility Analysis

Time

Project Schedule

Budget

Questions