Patricia Loyselle

Glenn Research Center, Cleveland, Ohio

Kevin Prokopius

Analex Corporation, Cleveland, Ohio

Teledyne Energy Systems, Inc., Proton Exchange 

Member (PEM) Fuel Cell Engineering 

Model Powerplant

Test Report: Initial Benchmark Tests in the Original Orientation

NASA/TM—2011-216225

August 2011
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Patricia Loyselle

Glenn Research Center, Cleveland, Ohio

Kevin Prokopius

Analex Corporation, Cleveland, Ohio

Teledyne Energy Systems, Inc., Proton Exchange 

Member (PEM) Fuel Cell Engineering 

Model Powerplant

Test Report: Initial Benchmark Tests in the Original Orientation

NASA/TM—2011-216225

August 2011

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
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Hanover, MD 21076–1320

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Level of Review: This material has been technically reviewed by technical management. 
NASA/TM—2011-216225 iii

Contents

1.0 PEM Fuel Cell Engineering Model (EM) Powerplant .........................................................................1

1.1 Description..................................................................................................................................1

2.0 Test Summaries....................................................................................................................................1

2.1 Calibration Series Test................................................................................................................2

2.2 Performance Load Profile Test ...................................................................................................2

2.3 Fifty Percent of Capability Test..................................................................................................3

3.0 Test Results..........................................................................................................................................3

3.1 Teledyne and GRC Acceptance Tests.........................................................................................3

3.2 Transient Response of the Powerplant to Changes in Load........................................................6

3.3 Calibration Series Tests ..............................................................................................................7

4.0 Conclusion..........................................................................................................................................13

Appendix A.—Detailed Test Descriptions .................................................................................................15

A.1 Calibration Series Test..............................................................................................................15

A.2 Performance Load Profile Test .................................................................................................16

A.3 Fifty Percent of Capability Test................................................................................................17

List of Tables

Table 1.—Engineering Model Design Goals................................................................................................2

Table 2.—Design Goals of the Teledyne Engineering Model Powerplant.................................................13

Table 3.—EM Calibration Series Test Conditions .....................................................................................15

Table 4.—EM Performance Load Profile Test Conditions.........................................................................16

Table 5.—EM Fifty Percent of Capability Test Conditions .......................................................................17

List of Figures

Figure 1.—Teledyne PEM fuel cell EM Powerplant in its original orientation. ..........................................2

Figure 2.—Comparison of Teledyne Acceptance Calibration Series test with initial GRC 

Calibration Series test...........................................................................................................................4

Figure 3.—Comparison of Teledyne Acceptance Calibration Series test with initial GRC 

Calibration Series test. Stack voltage at various power levels. ............................................................5

Figure 4.—Comparison of Teledyne Acceptance Performance Load Profile test with initial GRC 

Performance Load Profile test..............................................................................................................5

Figure 5.—Observation of the voltage response of the EM Powerplant during the transition from 

51 to 357 A...........................................................................................................................................6

Figure 6.—Observation of the voltage response of the EM Powerplant during the transition from 

357 to 51 A...........................................................................................................................................7

Figure 7.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test..............................................................................................................8

Figure 8.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Inlet and outlet hydrogen temperatures. .............................................9

Figure 9.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Inlet and outlet oxygen temperatures..................................................9

Figure 10.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Coolant inlet and outlet temperatures...............................................10

Figure 11.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile Test. Hydrogen inlet and outlet pressures................................................11
NASA/TM—2011-216225 iv

Figure 12.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Oxygen inlet and outlet pressures.....................................................11

Figure 13.—Fifty percent of capability test in the “A” orientation. ...........................................................12

Figure 14.—Fifty percent of capability test in the “A” orientation. Individual cell voltages.....................13
NASA/TM—2011-216225 1

Teledyne Energy Systems, Inc., Proton Exchange Member (PEM)

Fuel Cell Engineering Model Powerplant

Test Report: Initial Benchmark Tests in the Original Orientation

Patricia Loyselle

National Aeronautics and Space Administration

Glenn Research Center

Cleveland, Ohio 44135

Kevin Prokopius

Analex Corporation

Cleveland, Ohio 44135

1.0 PEM Fuel Cell Engineering Model (EM) Powerplant

Proton Exchange Membrane (PEM) fuel cell technology is the leading candidate to replace the aging 

alkaline fuel cell technology, currently used on the Shuttle, for future space missions. This test effort 

marks the final phase of a 5-yr development program that began under the Second Generation Reusable 

Launch Vehicle (RLV) Program, transitioned into the Next Generation Launch Technologies (NGLT) 

Program, and is now continuing under Constellation Systems in the Exploration Technology 

Development Program. This report details initial performance evaluation test results of the EM in its 

original orientation as shipped by the manufacturer. The specifics of these different tests are described in 

the following sections.

1.1 Description

The Teledyne Proton Exchange Membrane (PEM) Fuel Cell Engineering Model (EM) Powerplant 

consists of a water-cooled, hydrogen/oxygen PEM fuel cell stack along with supporting ancillaries and a 

separate control/data acquisition system (Figure 1).

The fuel cell stack is comprised of 117 individual cells divided into three subsections. Each 

subsection is comprised of 39 cells in a series configuration. The three subsections are connected in a 

parallel configuration. The fuel cell stack was designed to deliver between 2 and 12 kW of power within 

voltage regulation range of 33 to 27 VDC. The Fuel Cell product water is removed from the stack using 

recirculation pumps and gravity independent water separators and rejected outside of the powerplant. 

Waste heat is removed from the stack via an internal cooling loop. The powerplant cooling system in 

turns rejects the heat to a facility cooling system external to the powerplant. Additional powerplant design 

goals are outlined in Table 1.

2.0 Test Summaries 

The stability, performance, life, gravity independence and response time of the Teledyne Engineering 

Model Powerplant were evaluated using a series of tests under three physical orientations. These 

performance tests were conducted upon the Teledyne Engineering Model Powerplant to assess 

performance and stability over conditions anticipated to be encountered during operation under mission 

scenarios. Initial evaluation tests were conducted under the standard “A” orientation, as seen in Figure 1, 

to form a baseline performance metric. The results of these tests are described in this paper. A brief 

description of each test type follows below. Detailed information regarding operating parameters of each 

test is included in the Appendix A.
NASA/TM—2011-216225 2

Figure 1.—Teledyne PEM fuel cell EM Powerplant in its original orientation.

TABLE 1.—ENGINEERING MODEL DESIGN GOALS

Engineering Model Design Goals Verification Method

Produce 2 to 12 kW of electrical power within a voltage range of 33 to 27 VDC All tests

Gravity/orientation independent operation Operation under three 

physical orientations

Maintenance free operation for 3000 hr All tests

90% of the final change in voltage after a change in load shall occur within 0.2 sec Performance load profile 

calibration series

The power plant shall be capable of automatic startup to 3 kW in less than 5 sec if reactants are 

present, initial stack temperature is greater than 40 °F and no inerts are present.

50% of capability test

The power plant shall be capable of shutdown in less than 1 min All tests

The power plant shall be capable of operating on propellant grade (MIL PRF-27201C) and higher 

purity hydrogen and propellant grade (MIL PRF-25508F) and higher purity oxygen.

All tests

Operating Life shall be greater than 3000 hr All tests

Powerplant shall be capable of operation for 9 min at 5 kW without cooling from a secondary 

coolant loop

Loss of coolant test

The powerplant shall be capable of a minimum of 250 start/stop cycles All tests

2.1 Calibration Series Test

The Calibration Series Test was a reference test for the Engineering Model. The series is comprised 

of a Polarization Test and an abbreviated version of the Performance Load Profile Test. This test was 

performed at specified intervals during the evaluation of the Engineering Model at Teledyne, the NASA 

Glenn Research Center (GRC) and the NASA Johnson Space Center (JSC). The Calibration Series Test 

was used to quantify performance changes of the Engineering Model as a function of shipping, orientation 

effects, and damage as a result of testing and age. Voltage transitions were recorded at a rate of 200 kHz 

during the transition from 51 to 357 A and again at the transition from 357 to 51 A.

2.2 Performance Load Profile Test

The Performance Load Profile Test was a benchmark test for the Engineering Model. This test was 

used to evaluate the performance of the Engineering Model under different operational conditions, i.e.,
NASA/TM—2011-216225 3

orientation, vibration, etc. The Performance Load Profile Test was carried out at Teledyne and GRC.

Voltage transitions were recorded at a rate of 200 kHz during the transition from 51 to 357 A and again at 

the transition from 357 to 51 A.

2.3 Fifty Percent of Capability Test

The Fifty Percent of Capability Test was an evaluation of the speed of the response of the 

Engineering Model to loads after rapid start-up. The Engineering Model was started using the rapid startup procedure, which includes purging the unit of nitrogen and introduction of reactants but does not 

include a warm-up of the powerplant. Under normal start-up conditions, the powerplant is pre-warmed to 

45 °C prior to applying a power load. Within 5 sec of the start, the powerplant must be able to respond to 

a load app. 50 percent of the rated power. After completion of this test, the powerplant was shutdown and 

restarted using the normal start-up procedure for the remainder of the day’s testing. 

3.0 Test Results

3.1 Teledyne and GRC Acceptance Tests

Prior to delivery of the Engineering Model to the GRC, two acceptance tests were performed upon the 

unit at the Teledyne facility; a Calibration Series Test and Performance Load Profile Test. These tests 

were then repeated at the GRC Fuel Cell Test Laboratory (FCTL). The power load profiles applied 

(current drawn) during the two tests were identical at both facilities. As can be seen from Figure 2, the 

Calibration Series Tests performed at the two facilities were quite similar. The saw tooth pattern evident 

in the GRC data was the result of intermittent venting of impurities built up in the powerplant system. The 

powerplant was designed to operate “deadheaded” the majority of time, as the reactants were consumed 

the impurity concentration increased in the system. These impurities acted as a diluent to the reactants. As 

the impurity concentration in the system increased, the system performance reversibly degraded until the 

impurities were vented from the powerplant system. The powerplant impurity vent timing could be 

adjusted to reflect the purity of the incoming reactants. The lower the purity of the incoming reactant 

gases, the more frequently the vent was required. One of the design goals of the powerplant was operation 

under propellant grade reactants. This design goal enables the powerplant to share reactants from the 

propellant system rather than carrying reactants and tanks dedicated to the power subsystem. By 

eliminating the need for separate reactant tanks, this feature will result in significant mass savings. The 

reactant gases utilized at the GRC facility were propellant grade, a lower purity level than those used at 

the Teledyne facility.

GRC O2 = 99.5 percent

H2 = 99.997 percent

Teledyne O2 = 99.87 percent

H2 = 99.96 percent

The most significant difference observed in the tests at the two facilities occurred in the first half of 

the polarization curve. During the test at GRC, the stack voltage during the first half of the polarization 

curve was lower than that observed at Teledyne. However, during the second half of the polarization

curve and for the remainder of the test, the stack voltages observed at the two facilities were nearly 

identical. The depressed voltage observed at the initiation of the Calibration Series Test was likely due to 

minor drying of the fuel cell stack. Approximately one month elapsed between the acceptance tests at 

Teledyne and the initiation of testing at GRC. During that time the powerplant was removed from the 

Teledyne test facility, shipped to GRC and installed in the GRC FCTL. It is likely during the time

required for shipment and installation, the fuel cell stack dried out slightly resulting in a lower voltage at 

the initiation of the test. Shortly into the Calibration Series Test (app. 30 to 40 min), the stack had 

rehydrated and the stack voltage recovered to the levels observed at the Teledyne facility.
NASA/TM—2011-216225 4

EM Calibration Series

"A" Orientation

Teledyne 7/20/05 NASA GRC 8/26

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 Teledyne Acceptance Test 7/20/05 Current

Figure 2.—Comparison of Teledyne Acceptance Calibration Series test with initial GRC

Calibration Series test.

As can be seen from Figure 3, the Teledyne Engineering Model Powerplant has not met the design 

goal to produce 2 to 12 kW of electrical power within a voltage range of 33 to 27 VDC. At 2.28 kW, the 

stack voltage was 33.509 V and at 12.97 kW of electrical power, the stack voltage was 28.4 V. At higher 

power loads, the powerplant operates within the voltage range. However, at power loads below 3 kW, the 

fuel cell stack voltage was higher than 33 V. As a result, some voltage regulation would be required 

during mission operations.

As can be seen in Figure 4, the Performance Load Profile Tests performed at the Teledyne facility 

and the GRC FCTL were also quite similar. Again, the saw tooth pattern observed in the GRC data was a 

result of build-up and release of reactant impurities as was observed in the Calibration Series Test. The 

stack voltages observed at both facilities were nearly identical.
NASA/TM—2011-216225 5

EM Calibration Series

"A" Orientation

Teledyne 7/20/05 NASA GRC 8/26

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

5

10

15

20

25

30

35

Power (kW)

Teledyne Acceptance Test 7/20/05 NASA GRC 8/26/05

Power (Teledyne) Power (NASA GRC)

Figure 3.—Comparison of Teledyne Acceptance Calibration Series test with initial GRC

Calibration Series test. Stack voltage at various power levels.

EM Performance Load Profile Test

"A" Orientation

Teledyne 7/29/05 NASA GRC 8/29

20

25

30

35

40

0 1 2 3 4 5 6 7 8 9

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC Initial Test Teledyne Acceptance Test Current

Figure 4.—Comparison of Teledyne Acceptance Performance Load Profile test with initial GRC

Performance Load Profile test.
NASA/TM—2011-216225 6

3.2 Transient Response of the Powerplant to Changes in Load

During the course of the Calibration Series Test and Performance Load Profile Test, the response of 

the powerplant to changes in load was monitored at two points during the test: (1) from an applied load of 

51 to 357 A (Figure 5) and (2) from 357 to 51 A (Figure 6). A high-speed data acquisition system 

operating at 200 kHz was employed to monitor the applied load current and the stack voltage during these 

transitions. As can be seen in Figure 5, during the transition from 51 to 357 A, the electronic load initially 

overshoots the requested current, but stabilized quickly. The fuel cell stack voltage followed the load 

current but also overshot and followed a ringing pattern until it stabilized in less than 2 msec. The cause 

of the fuel cell stack voltage overshoot and ringing pattern is unknown. It could be due to pressure swings 

within the fuel cell stack caused by changes in reactant consumption, changes in flow rates of some type 

of electrical interference in the signal, although this was not observed in the current signal. Currently the 

cause is unknown, but the phenomenon lasted less than 2 msec.

As can be observed in Figure 5, the stack voltage continued to decrease after the ringing pattern 

subsided. The reactant flow rates did not change when the power load was changed from 51 to 357 A.

However, the reactant consumption rate did change. Therefore, the stoichiometry of the reactant delivery 

to the fuel cell stack changed. At 51 A, the calculated hydrogen and oxygen stoichiometry was 14.8 and 

28.5, respectively. At 357 A, the calculated hydrogen and oxygen stoichiometry was 3 and 5 respectively.

At the higher power load (higher current), the reactant flow rate through the fuel cell stack was reduced 

relative to the lower power load (lower current). Product water was removed from the stack via reactant 

flow rates higher than required by the power demand. Therefore, when the power demand increased and 

the reactant flow rates did not, product water was not removed from the stack as well. The slight 

reduction in stack voltage over a few milliseconds was likely the result of a change in the product water 

remaining in the stack; i.e., a slight increase in resident product water will result in a slight decrease in the 

stack voltage.

EM Performance Load Profil

"A" Orientation

51 Amps to 357 Amps

0

5

10

15

20

25

30

35

40

0.052 0.054 0.056 0.058 0.06 0.062 0.064 0.066

Time (Sec)

0

50

100

150

200

250

300

350

400

450

Current (A)

Stack Voltage

Current

Figure 5.—Observation of the voltage response of the EM Powerplant during the transition 

from 51 to 357 A.
NASA/TM—2011-216225 7

EM Performance Load Profil

"A" Orientation

357 Amps to 51 Amps

0

10

20

30

40

50

60

0.048 0.049 0.05 0.051 0.052 0.053 0.054 0.055 0.056 0.057 0.058

Time (Sec)

0

50

100

150

200

250

300

350

400

Current (A)

Stack Voltage

Current

Figure 6.—Observation of the voltage response of the EM Powerplant during the transition 

from 357 to 51 A.

As can be seen in Figure 5, after approximately 8 msec, the stack voltage reached 27.4 V. The final 

voltage observed after this transition was 29.1 V. Therefore, the powerplant reached greater than 

90 percent of the final voltage within 8 msec. The powerplant met the design requirement that the 

90 percent of the final change in voltage after a change in load should occur within 2 sec.

During the transition from 357 to 51 A, the powerplant again responded and stabilized rapidly, as can 

be viewed in Figure 6. During the transition to a lower power draw (51 A), the stack voltage continued to 

increase slightly before stabilizing as discussed before, the reactant stoichiometry again changed, this 

time going to a higher level. As a result, more product water was being removed from the stack which 

resulted in a slightly higher stack voltage.

As can be seen in Figure 6, after approximately 8 msec, the stack voltage was 32.6 V. The final 

voltage observed after this transition was 33.7 V. Therefore, the powerplant reached greater than 

90 percent of the final voltage within 8 msec. Again, the powerplant met the design requirement that 

90 percent of the final change in voltage after a change in load should occur within 2 sec.

3.3 Calibration Series Tests

As discussed previously, the Calibration Series Test was a reference test of the performance of the 

powerplant over time and after any system modifications, repairs or relocations. During this initial series 

of benchmark tests in the “A” orientation, it was not likely that changes in the performance of the 

powerplant occurred as a result of degradation or age between the two Calibration Series Tests. Only four 

days and a run time of approximately 12 hr had elapsed. However, as can be seen in Figure 7, slight 

differences were evident in the Calibration Series Tests collected on August 26, 2005, and August 30, 

2005. All controllable test conditions were the same for both test runs; however, small variations of the 

operational conditions were possible. In order to determine the cause of the variance between the two test 

runs, the operating conditions for each test run were evaluated.
NASA/TM—2011-216225 8

EM Calibration Series

"A" Orientation

NASA GRC 8/26/05 NASA GRC 8/30/05 (Post Performance Load Profi 

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 NASA GRC 8/30/05 Current

Figure 7.—Comparison of the Calibration Series test in the “A” orientation before and after the

Performance Load Profile test.

Fuel cell performance is dependent upon the temperature at which the reaction occurs with a higher 

temperature enhancing performance. At the GRC FCTL, hydrogen and oxygen reactants were stored 

outside of the test facility in tube trailers. The temperature of the reactants as they enter the test facility 

can vary depending upon the outside ambient temperature. As can be seen in Figure 8 and Figure 9, the 

hydrogen and oxygen inlet temperatures observed varied slightly between run days. The fuel cell 

powerplant was primarily operated “dead-ended”, therefore hydrogen and oxygen are only added to the 

powerplant to replace the reactants consumed in the fuel cell reaction. The remainder of the reactant gas 

that is unconsumed was recirculated throughout the powerplant. The outlet reactant gas temperature was a 

good measure of the temperature within the fuel cell stack. As can be seen in Figure 8 and Figure 9, the 

outlet temperature of reactant gases closely followed the load applied to the fuel cell powerplant. As the 

load was increased, the efficiency of the fuel cell reaction decreased, resulting in the generation of more 

waste heat. This waste heat is partially removed from the fuel cell stack via the exiting reactant gases. The 

hydrogen and oxygen temperatures, as they exited the fuel cell stack, were nearly identical between the 

two days. Therefore, the differences in performance were not a result of reactant temperature.
NASA/TM—2011-216225 9

EM Calibration Series

"A" Orientation

NASA GRC 8/26/05 NASA GRC 8/30/05 (Post Performance Load Profile 

20

25

30

35

40

45

50

55

60

65

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr)

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 NASA GRC 8/30/05

Hydrogen Inlet Temperature 8/30/05 Hydrogen Inlet Temperature 8/26/05

Hydrogen Outlet Temperature 8/30/05 Hydrogen Outlet Temperature 8/26/05

Current

Figure 8.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Inlet and outlet hydrogen temperatures.

EM Calibration Series

"A" Orientation

NASA GRC 8/26/05 NASA GRC 8/30/05 (Post Performance Load Profi 

20

25

30

35

40

45

50

55

60

65

70

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 NASA GRC 8/30/05

Oxygen Inlet Temperature 8/30/05 Oxygen Inlet Temperature 8/26/05

Oxygen Outlet Temperature 8/30/05 Oxygen Outlet Temperature 8/26/05

Current

Figure 9.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Inlet and outlet oxygen temperatures.
NASA/TM—2011-216225 10

Likewise, the coolant temperature also influences the temperature at which the fuel cell reaction 

occurs. The powerplant coolant system was a recirculating loop which transferred heat from the fuel cell 

to a heat exchanger. The heat exchanger in turn rejected heat to an external cooling loop (the fuel cell 

facility chiller system). As can be seen in Figure 10, the coolant loop temperatures also closely followed 

the power load profile as did the reactant gas temperatures. In a similar fashion to the reactant outlet 

temperatures, the inlet and outlet temperatures of the coolant system were consistent between the 

Calibration Series Tests runs on August 26, and August 30. Therefore, it is not likely that temperature 

variations between the two days were responsible for the performance variation observed.

Fuel cell performance is also dependent upon reactant pressures, with higher pressures generally 

improving overall performance. In Figure 11 and Figure 12, the inlet and outlet reactant pressures are 

plotted with the voltage and current data. As can be seen, in Figure 11, the hydrogen pressure was slightly 

higher during the August 26 Calibration Series test than was observed on August 30. The reactant 

operating pressure was 6 psig. The hydrogen inlet pressure was approximately 0.3 to 0.6 psig higher on 

August 26, 2005, than on August 30, 2005. This 5 to 10 percent difference in inlet hydrogen pressure 

resulted in a 0.4 to 0.6 V difference in the stack voltages. The higher hydrogen pressure improved the fuel 

cell performance resulting in the slightly higher stack voltage observed during the August 26 Calibration 

Series Test run.

EM Calibration Series

"A" Orientation

NASA GRC 8/26/05 NASA GRC 8/30/05 (Post Performance Load Profi 

20

25

30

35

40

45

50

55

60

65

70

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 NASA GRC 8/30/05 Coolant In 8/26/05 Coolant Out 8/26/0

Coolant In 8/30/05 Coolant Out 8/30/05 Current

Figure 10.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Coolant inlet and outlet temperatures.
NASA/TM—2011-216225 11

EM Calibration Series

"A" Orientation

NASA GRC 8/26/05 NASA GRC 8/30/05 (Post Performance Load Profi 

15

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 NASA GRC 8/30/05

H2 Inlet Pressure 8/26/05 H2 Outlet Pressure 8/26/05

H2 Inlet Pressure 8/30/05 H2 Outlet Pressure 8/30/05

Current

Figure 11.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile Test. Hydrogen inlet and outlet pressures.

EM Calibration Series

"A" Orientation

NASA GRC 8/26/05 NASA GRC 8/30/05 (Post Performance Load Profil 

15

20

25

30

35

40

0 0.5 1 1.5 2 2.5 3

Elapsed Time (Hr

0

200

400

600

800

1000

1200

Current (A)

NASA GRC 8/26/05 NASA GRC 8/30/05

O2 Inlet Pressure 8/26/05 O2 Outlet Pressure 8/26/05

O2 Inlet Pressure 8/30/05 O2 Outlet Pressure 8/30/05

Current

Figure 12.—Comparison of the Calibration Series test in the “A” orientation before and after the 

Performance Load Profile test. Oxygen inlet and outlet pressures.
NASA/TM—2011-216225 12

Fifty Percent Capability Five Seconds Af 

Start

0

5

10

15

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30

35

40

45

0.00 20.00 40.00 60.00 80.00 100.00 120.00

Time (Sec)

0

20

40

60

80

100

120

140

160

180

Current (A)

Stack Voltage Power (kW) Ave. Voltage Ave. Power Current

Figure 13.—Fifty percent of capability test in the “A” orientation.

The Fifty Percent of Capability Test demonstrated the ability of the powerplant to deliver Fifty 

Percent of rated capacity within 5 sec after the start of the powerplant. Under normal start-up conditions, 

the powerplant is preheated to a set temperature prior to the imposition of a power load. During rapid 

start-up, the inerts, i.e., nitrogen, were purged from the powerplant system prior to start; however, no prewarming of the fuel cell stack or powerplant occurred. When the powerplant was started under this 

method, the ancillary system, i.e., the reactant recirculation pumps and water separators were started and 

the reactant supply solenoid valves were opened. The powerplant system was designed to bring the 

ancillary system online and to be ready to provide power within 5 sec of start. As can be seen in Figure 

13, a load equivalent to 50 percent of its capability was applied to the powerplant 5 sec after start. The 

average power and average voltage plotted represent the levels seen during normal operation at the same 

power level. Upon application of the load, the powerplant voltage and power quickly rose to levels seen 

during normal start-up and operation.

In Figure 14, the individual cell voltages within the stack are plotted. As can be seen, within the first 

few seconds after start-up the cell voltages were closely spaced and maintained their spacing during the 

duration of the test. This indicates that even under rapid start-up conditions, the pressure and temperature 

was consistent across the stack. Cell 1 is the only outlier and may have exhibited decreased performance 

for a number of reasons including lower gas humidity or temperatures.
NASA/TM—2011-216225 13

Fifty Percent Capability Five Seconds After 

Start

"A" Orientation

0.7

0.75

0.8

0.85

0.9

0.95

1

1.05

1.1

0 10 20 30 40 50 60

Time (Sec)

0

20

40

60

80

100

120

140

160

180

Current (A)

Cell #1

Current

Cells 2 - 117

Figure 14.—Fifty percent of capability test in the “A” orientation. Individual cell voltages.

4.0 Conclusion

The initial evaluation of the Teledyne Engineering Model Powerplant was conducted to measure the 

performance over a variety conditions and power load profiles. This report details these initial 

performance evaluation test results of the EM in its original orientation as shipped by the manufacturer.

Table 2 outlines the original design goals for the Teledyne Engineering Model and specifies the goals that 

were demonstrated during the initial evaluation testing. The remaining tests will be used to quantify:

• Performance and any changes in performance during operation under different physical 

orientations.

• Maintenance intervals, operating life, performance degradation, and cycle life.

• Stability over extended duration operations (240 hr).

• Powerplant response to loss of cooling.

TABLE 2.—DESIGN GOALS OF THE TELEDYNE ENGINEERING MODEL POWERPLANT

Engineering Model Design Goals Tested? Met?

Produce 2 to 12 kW of electrical power within a voltage range of 33 to 27 VDC Tested Did not meet

Gravity/orientation independent operation Not tested

Maintenance free operation for 3000 hr Not tested

90% of Final change in voltage shall occur within 0.2 sec. Tested Met

The power plant shall be capable of automatic startup to 3 kW in less than 5 sec if reactants 

are present, initial stack temperature is greater than 40 °F and no inerts are present.

Tested Met

The power plant shall be capable of shutdown in less than 1 min Not tested

The power plant shall be capable of operating on propellant grade (MIL PRF-27201C) and 

higher purity hydrogen and propellant grade (MIL PRF-25508F) and higher purity oxygen.

Tested Met

Operating life will be greater than 3000 hr Not tested

Powerplant shall be capable of operation for 9 min at 5 kW without cooling from a 

secondary coolant loop.

Not tested

Minimum of 250 start / stop cycles life design goal Not tested

NASA/TM—2011-216225 15

Appendix A.—Detailed Test Descriptions

The following tables and descriptions quantify the exact currents, durations and recording intervals 

used during the test described in this paper.

A.1 Calibration Series Test

The Calibration Series Test was a reference test of the Engineering Model. The series was comprised 

of a Polarization Test and an abbreviated version of the Performance Load Profile Test. This test was 

performed at specified intervals during the evaluation of the Engineering Model at Teledyne, GRC and 

JSC. The calibration series test was used to quantify performance changes of the Engineering Model as a 

function of shipping, orientation effects, damage as a result of testing and age. The stack voltage in the 

table was the average of the last four readings taken July 20, 2005, during the calibration series 

acceptance test at Teledyne. Voltage transients occurred at the element numbers marked with an asterisk 

and at these locations, data was recorded at 200 kHz using the DataMax software.

TABLE 3.—EM CALIBRATION SERIES TEST CONDITIONS

Element

no.

Increment 

time

(sec)

Current

(A)

Teledyne 

data 

recording 

interval

(sec)

GRC data 

recording 

interval

(sec)

Stack 

voltage

(V)

Total time

(sec)

Current 

density

(mA/cm2 )

1 300 0 5 5 40.34 300 0

2 300 22.65 5 5 35.04 600 25

3 300 45.3 5 5 34.13 900 50

4 300 67.95 5 5 33.47 1200 75

5 300 90.6 5 5 32.93 1500 100

6 300 135.9 5 5 32.06 1800 150

7 300 181.2 5 5 31.47 2100 200

8 300 271.8 5 5 30.23 2400 300

9 300 362.4 5 5 29.27 2700 400

10 300 453 5 5 28.31 3000 500

11 300 362.4 5 5 29.22 3300 400

12 300 271.8 5 5 30.22 3600 300

13 300 181.2 5 5 31.31 3900 200

14 300 135.9 5 5 32.07 4200 150

15 300 90.6 5 5 32.93 4500 100

16 300 67.95 5 5 33.46 4800 75

17 300 45.3 5 5 34.14 5100 50

18 300 22.65 5 5 35.17 5400 25

19 300 0 5 5 40.74 5700 0

20 20 0 5 5 40.74 5720 0

21 120 174 5 5 31.17 5840 192

22 1200 135 5 5 31.83 7040 149

23a 55 51 5 5 33.91 7095 57

*23b 5 51 5 1 7100 57

*24a 5 357 5 1 7105 394

24b 55 357 5 5 28.72 7160 394

25 60 51 5 5 33.96 7220 57

26 60 192 5 5 30.86 7280 212

27 180 468 5 5 27.91 7460 516

28 1200 192 5 5 30.87 8660 212

29a 55 357 5 5 28.80 8715 394

*29b 5 357 5 1 8720 394

*30a 5 51 5 1 8725 57

30b 55 51 5 5 34.06 8780 57

31 30 0 5 5 40.33 8810 0
NASA/TM—2011-216225 16

TABLE 3.—EM CALIBRATION SERIES TEST CONDITIONS

Element

no.

Increment 

time

(sec)

Current

(A)

Teledyne 

data 

recording 

interval

(sec)

GRC data 

recording 

interval

(sec)

Stack 

voltage

(V)

Total time

(sec)

Current 

density

(mA/cm2 )

32 60 192 5 5 30.88 8870 212

33 40 51 5 5 33.92 8910 57

34 60 192 5 5 30.84 8970 212

35 40 468 5 5 27.40 9010 516

36 60 192 5 5 31.03 9070 212

37 40 104 5 5 32.60 9110 115

38 60 192 5 5 30.88 9170 212

39 40 431 5 5 27.76 9210 476

40 60 192 5 5 31.00 9270 212

41 40 164 5 5 31.42 9310 180

42 60 192 5 5 31.03 9370 212

43 40 357 5 5 28.73 9410 394

44 60 192 5 5 31.06 9470 212

45 40 226 5 5 30.49 9510 249

46 60 192 5 5 31.00 9570 212

47 40 288 5 5 29.56 9610 318

48 150 192 5 5 30.92 9760 212

49 60 0 5 5 40.37 9820 0

A.2 Performance Load Profile Test

The Performance Load Profile Test was a benchmark test of the Engineering Model. This test was 

used to evaluate the performance of the Engineering Model under different operational conditions, i.e.,

orientation, vibration, etc. The Performance Load Profile Test was carried out at Teledyne and GRC. The 

stack voltage in the table was the average voltage during each step as observed July 19, 2005, during the 

performance load profile acceptance test at Teledyne. Voltage transients occurred at the element numbers

marked with an asterisk and at these locations, data was recorded at 200 kHz using the DataMax software.

TABLE 4.—EM PERFORMANCE LOAD PROFILE TEST CONDITIONS

Element

no.

Increment 

time

(sec)

Current

(A)

Teledyne 

data 

recording 

interval

(sec)

GRC data 

recording 

interval

(sec)

Stack 

voltage

(V)

Total time

(sec)

Current 

density

(mA/cm2 )

1 30 0 5 5 39.93 30 0

2 120 174 5 5 31.97 150 192

3 3600 135 5 5 32.11 3750 149

4a 3295 51 5 5 33.70 7045 57

*4b 5 51 5 1 7050 57

*5a 5 357 5 1 7055 394

5b 895 357 5 5 29.04 7950 394

6 3600 51 5 5 33.75 11550 57

7 960 192 5 5 30.77 12510 212

8 180 468 5 5 27.63 12690 516

9 6120 192 5 5 30.82 18810 212

10a 895 357 5 5 28.80 19705 394

*10b 5 357 5 1 19710 394

*11a 5 51 5 1 19715 57

11b 1675 51 5 5 33.75 21390 57

12 30 0 5 5 40.32 21420 0.0

13 860 192 5 5 30.75 22280 212

14 40 51 5 5 33.89 22320 57
NASA/TM—2011-216225 17

TABLE 4.—EM PERFORMANCE LOAD PROFILE TEST CONDITIONS

Element

no.

Increment 

time

(sec)

Current

(A)

Teledyne 

data 

recording 

interval

(sec)

GRC data 

recording 

interval

(sec)

Stack 

voltage

(V)

Total time

(sec)

Current 

density

(mA/cm2 )

15 860 192 5 5 30.74 23180 212

16 40 468 5 5 27.13 23220 516

17 860 192 5 5 30.82 24080 212

18 40 104 5 5 32.48 24120 115

19 860 192 5 5 30.77 24980 212

20 40 431 5 5 27.57 25020 476

21 860 192 5 5 30.80 25880 212

22 40 164 5 5 31.21 25920 180

23 860 192 5 5 30.78 26780 212

24 40 357 5 5 28.48 26820 394

25 860 192 5 5 30.79 27680 212

26 40 226 5 5 30.20 27720 249

27 860 192 5 5 30.77 28580 212

28 40 288 5 5 29.38 28620 318

29 150 192 5 5 30.82 28770 212

30 60 0 5 5 40.40 28830 0

A.3 Fifty Percent of Capability Test

The Fifty Percent of Capability Test was an evaluation of the speed of the response of the 

Engineering Model to loads after Rapid Start-Up. The Engineering Model was started using the rapid start 

procedure, which included purging the unit of nitrogen but did not include a warm-up of the fuel cell or 

powerplant. After completion of this test, the powerplant was shutdown and restarted using the normal 

start-up procedure for the remainder of the day’s testing. The stack voltage in the table was the average 

voltage during each step as observed July 19, 2005, during the performance load profile acceptance test at 

Teledyne.

TABLE 5.—EM FIFTY PERCENT OF CAPABILITY TEST CONDITIONS

Element

no.

Increment 

time

(sec)

Current

(A)

Teledyne 

data 

recording 

interval

(sec)

GRC data 

recording 

interval

(sec)

Stack 

voltage

(V)

Total time

(sec)

Current 

density

(mA/cm2 )

1 5 0 1 1 39.93 5 0

2 120 164 1 1 31.21 125 181

3 5 0 1 1 130 0
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4. TITLE AND SUBTITLE

Teledyne Energy Systems, Inc., Proton Exchange Member (PEM) Fuel Cell Engineering 

Model Powerplant 

Test Report: Initial Benchmark Tests in the Original Orientation

5a. CONTRACT NUMBER

5b. GRANT NUMBER

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6. AUTHOR(S)

Loyselle, Patricia; Prokopius, Kevin 

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WBS 038957.04.06.03.03 

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National Aeronautics and Space Administration 

John H. Glenn Research Center at Lewis Field 

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Available electronically at http://gltrs.grc.nasa.gov 

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14. ABSTRACT

Proton Exchange Membrane (PEM) fuel cell technology is the leading candidate to replace the alkaline fuel cell technology, currently used 

on the Shuttle, for future space missions. During a 5-yr development program, a PEM fuel cell powerplant was developed. This report 

details the initial performance evaluation test results of the powerplant. 

15. SUBJECT TERMS

Fuel cell power plants; Electric power supplies; Energy sources; Spacecraft power supplies; Electric power; Energy storage; Fuel cells 

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