DEVELOPMENT OF A HIGH RELIABILITY COMPACT …...system storage density • Relatively high TRL • Provides high purity reactant to FC system • Can be refueled using water and electricity

Authors: B. Wynne, C. Diffenderfer, S. Ferguson, J. Keyser, M. Miller, B. Sievers, Y. Song (TESI) K. Araghi, A. Vasquez (NASA JSC)

Fuel Cell Seminar, October 22, 2013

DEVELOPMENT OF A HIGH RELIABILITY COMPACT AIR

INDEPENDENT PEMFC POWER SYSTEM

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https://ntrs.nasa.gov/search.jsp?R=20140002872 2020-07-08T18:32:17+00:00Z

Fuel Cell Seminar October 22, 2013

OVERVIEW

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Autonomous Underwater Vehicles (AUV’s) have received increased attention in recent years as military and commercial users look for means to maintain a mobile and persistent presence in the undersea world. Teledyne Energy Systems, Inc. (TESI) is committed to meeting the energy needs for these missions


BACKGROUND

TESI has been developing EDR (Ejector Driven Reactants) systems for air independent applications

What’s Important?

• Space – reliability, efficiency, and mass are priority

• Power levels from 0.5 kW – 15 kW

• Work closely with NASA

• EDR systems have highest demonstrated TRL

• AUVs - reliability, efficiency, and volume are critical

• Power levels from 0.5 kW to 70+ kW

• Working with NASA JSC under SAA

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AUV REQUIREMENTS

Extended Mission Duration

• Mission lengths from 1 – 70 days needed depending on platform

• Battery systems cannot meet the requirement

• TESI LTPEM systems can meet these demands when paired with the appropriate reactant storage

Neutral Buoyancy/Closed Cycle

• TESI proprietary Integrated BOP system compactly captures and stores all byproducts onboard

High Reliability

• TESI long history of air independent LTPEM FC systems development

• Use of high TRL technologies

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REACTANT (ENERGY) STORAGE

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TESI trade studies indicate LH2 and LOX provide exceptional reactant

system storage density

• Relatively high TRL

• Provides high purity

reactant to FC system

• Can be refueled using

water and electricity

0

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Sto

red

En

erg

y (k

wh

)

Energy Section Volume (L)

UUV Energy Storage Comparison


TESI LTPEM FC SYSTEM ADVANTAGES

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• Load following

• Able to respond quickly to load changes

• FC stack responds in µs

• Custom BOP sized to meet load profile

1A to 400A

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100

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450

50 52 54 56 58 60 62 64 66 68 70

TIME (milliseconds)

AM

PS

0.50

0.55

0.60

0.65

0.70

0.75

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0.85

0.90

0.95

1.00

VO

LT

S

Current

Potential

•High TRL

•Demonstrated long life with H2/O2 reactants

•EDR systems have proven reliability, used extensively in automotive FC systems

•Compact

•Highly integrated subsystems

• Water separation/reactant conditioning performed in FC

• Reactant pressure and flow control integrated into the BOP endplate

• Working with NASA JSC on advanced ejector technology


NASA – TESI DEVELOPMENT UNDER SAA

NASA JSC

• Ejector – Regulator performance test data

• Design assistance during incorporation of pressure regulation/ejector into FC endplate

TESI

• BOP endplate design

• Design of planar reactant conditioning assemblies

• BOP endplate fabrication

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JSC System

Teledyne Stack


NASA JSC DEVELOPED PASSIVE EJECTOR

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Spring

Diaphragm

Ejector

From

Reactant

Supply

Sense Line

To Fuel Cell Poppet

Circulation Flow

From Fuel Cell

delta-P

Mixer

Section Diffuser

Section

Dome Control

Regulator


BOP/STACK INTEGRATION

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Reactant

Conditioning/H2O

Separation

Sensors and

Valves

Flow Control

Plate

FC Stack Stand alone

Ejector-Regulator

developed by

NASA JSC

Integrated

BOP/FC

Concept

NASA JSC breadboard system


EJECTOR VERIFICATION TESTING AT TELEDYNE

In-house test results of the stand alone hardware were similar to

NASA’s test measurements

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0.1

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Max

imum

Eje

ctor

Dev

elop

ed P

ress

ure

Dif

fere

nce,

psi

d

4 5 6 7 8 9

102 3 4 5

Mixer to Jet Nozzle Diameter Ratio

2 3 4 5 6 7 8 9100

2 3 4 5 6 7 8 91000

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Mixer to Jet Nozzle Area Ratio

500 psig Motive Pressure



Calculated Values

Motive Pressure: ~200 psig





NASA JSC Data from 2010

y = 95x-1.75

0.1

1.0

10.0

1 10

Suct

ion

Pre

ssu

re D

eve

lop

ed

(p

sid

)

Mixer Diameter to Nozzle Diameter (ratio)

Mixer to Nozzle Diameter Ratio vs Suction Pressure

185 psig Dry N2 Supply Gas, 4.400 Mixer Depth

TESI Data from 2012


EJECTOR OPTIMIZATION AT TELEDYNE

Stand alone ejector-regulator was limited to a constant volume mixer section

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• A diverging taper angle was added,

the taper is a little greater than ideal,

but reduces manufacturing costs

• Features needed to be added to

facilitate mixer installation, removal,

and depth adjustment


EJECTOR TESTING AT TELEDYNE

Comparison of losses developed by new and old mixers

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Theoretical Performance

(Constant Area Mixer) Actual Performance

(Constant Area Mixer)

Old Mixer New Mixer

Theoretical Performance

(Constant Area Mixer)

Actual Performance

(Venturi Mixer)


PASSIVE PLANAR WATER SEPARATION THEORY

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TESI planar separators completely remove liquid water

from the reactants exiting the FC stack by incorporating

a hydrophilic water separation membrane.


• Less volume - incorporated into the FC stack • Thermal advantage - controlled temperature to maintain desired

dew point • Gravity independent – can be configured for zero G or changing

orientations in 1G (pitch and roll) • Testing has confirmed complete separation up to 10 kWe

PASSIVE PLANAR WATER SEPARATION

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Advantages of planar water separation

0.0%

20.0%

40.0%

60.0%

80.0%

100.0%

120.0%

<1 kW, 45 deg. 3 kW, 45 deg 10 kW, 45 deg 3 kw, norm 10 kW, norm 10 kW, 45 deg

Wat

er

Tran

sfe

r R

ate

Test Conditions

Planar Cell Water Removal


COMPACT FUEL CELL BALANCE OF PLANT

• Integrated BOP provides a

compact package for the

ejectors, instrumentation,

controls, and flow paths.

• Internal manifold design

provides a much more

compact BOP compared to

traditional BOP layout

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INTEGRATED EJECTOR-REGULATOR AND WATER MANAGEMENT SYSTEM

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FC Stack

Integrated

BOP

Reactant/H2O

Separation and

Conditioning


CONCLUSIONS, FUTURE WORK

• Compact Ejector based systems have been demonstrated by TESI and NASA in a number of system configurations

• Planar water separation and conditioning has been tested in ex-situ test beds and breadboard demonstrations with equivalent H2O production rates up to 10 kWe

• Fully integrated systems will be demonstrated early in 2014

• Additional IR&D spending on advanced variable orifice ejectors is planned for 2014

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Documents

DEVELOPMENT OF A HIGH RELIABILITY COMPACT …...system storage density • Relatively high TRL • Provides high purity reactant to FC system • Can be refueled using water and electricity