DL HYDROGEN-B / FUEL CELLS SYSTEMS TRAINER
This trainer mustbedesigned for the study of fuelcellsystems. Itmustteachtheirengineeringprinciples and itmustallowperforming a set of experiments for educational purposes.Itmustbe safe and easy tobeoperated.
Furthermore, itmustbe very flexibleand suitable for the understanding of basicprinciplesaswellas more complextechnologyconcepts.Basically, the trainer musthave modular structureconsisting in abench top frame where itmustbepossibletofix the necessaryisolatedmodulestoperform the experiments.
The trainer mustinclude the followingmodules:
- a storagecanistermodule of 225 l
- a 100W PEM fuelcellmodule with performance: 14V at 7.2A; consumption of H2:
1.4l/min and itincludes the electronic controller; thismoduleshallbe complete with sensors (pressure, flow and temperature) for
measuring and for further acquisition;
- a measurementinstrumentsmodule, containing 2 voltmeters (f.s.: 40V), 1 ammeter (f.s.: 10A), and 3 displays for pressure, flow and temperature
- a DC/DC convertermodule with output 12V, 8A
- a load with onehalogenlamp (12V, 20W) and one LED lamp (12V, 3x1W)
- a variablelogarithmicrheostatmodule (1.5Ω ÷ 17Ω, 100W, Imax:8A)
- a batterymodule.
HydrogenStorageModule
Modulethatmustbedesigned for a safe and reliablereversiblestorage of pure hydrogenaccordingto thetechnique of metal hydrides.
Normalcapacity: 18.9 g (0.212 Nm3) of Hydrogen
Metal Hydridealloy: AB2 model
Volume of the entire system: 0.5 litres
Mass of the entire system: 2.2 kg
Maximumworkingpressure: 30 bar
Maximum test pressure: 300 bar
H2 maximumpressure for charging: < 30 bar (static)
Cooling temperature for the minimum charge: > 5°C
Maximumworking temperature: < 65°C
The storage system in metal hydridesshallconsist of:
- 1 outercasing of stainless steel for cooling/heating water
- 7 internalmodules: stainless steel pressurevesselscertifiedto TPED (directive 99/36/EU)
- 1 stop valve or quick-action valve.
Mainmodule of the trainer and itshallbringtogether the essentialelementssuchas the PEM fuelcell, its controller and the necessarysensors for the study. In particolar, itshall include:
Bourdonpressuregauge:instrumentusedtomeasure the pressure of the hydrogen coming from the storagemodule; hydrogenshallreach the instrument already reducedtoabout 0.5bar through the kit, supplied and connectedtoits input (H2 IN), thatshallbe abletobringpressuretothesevalues.
Pressuresensor:designed for use with aggressive pressure media found in many industrial and processapplications; the stainless steel isolationdiaphragm and fullyweldedstainless steel pressuremoduleshall ensureexcellent media compatibilitywithoutcompromising the performance.Integralelectronicsshallprovide a two-wire 4 to 20mA output proportionaltoappliedpressure (0 –1bar). The terminals of thispressuresensorshallbeavailable on the right side identifiedbyPressureSensor OUT.
The ratedpressurerangeshall beexceededby 4xFS withoutdegrading performance and the containmentis 6xFS.
The supplyVoltageshallbe 9 to 28 Vdc and itsoperating temperature rangeshallbe -4°F to 176°F (-20°C to80°C).
Flow sensor:high-accuracysensingelement with high precision and fast response. The mainspecificationsshallbe the following:
Flow Range 0 to 3 L/min
SupplyVoltage 10.8 to 26.4 Vdc
Analogue Output
- Air: 1 to 5V
- Hydrogen: V = [(1.44 – 1)/1.4] x (L/min) +1
Temperature Range0 to 50°C
The terminals of thissensorshallbe available on the right side identifiedby Flow Sensor OUT.
Precision centigrade temperature sensor:
external and fixeddevice in direct contact with the PEM fuelcellto monitor its temperature. The output voltageshallbe linearlyproportionalto the Celsius (Centigrade) temperature. Thissensorthusshallhaveanadvantageoverlinear temperature sensorscalibrated in °Kelvin, as the usershallnot berequiredtosubtract a largeconstantvoltagefromits output toobtainconvenient Centigrade scaling.
The deviceshall notrequireanyexternalcalibration or trimmingtoprovidetypicalaccuracies of ±¼°C at room temperature and ±¾°C over a full −55°C to +150°C temperature range. The mainfeaturesshallbe the following:
Calibrateddirectly in °Celsius (Centigrade)
Linear +10mV/°C scale factor
0.5°C accuracy (at +25°C)
Rated for full −55°C to +150°C range
Operatesfrom 4 to 30 volts
Lessthan 60 μA currentdrain
Low self-heating, 0.08°C in still air
Nonlinearityonly ±¼°C typical
Low impedance output, 0.1 Ω for 1 mAload
The terminals of this temperature sensorshallbeavailable on the right side identifiedbyTemp. Sensor OUT.
H2 Supply Valve, PEM FuelCell and Purging Valve: the fuelcell controller shallbeplaced inside the module and shallactas controller.
The switch SCU shallbeusedto eliminate the effect “short-circuit” of the stackconditioning (offposition) and the T sensorshallbentegratedinto the fuelcell controller.
The external DC Battery (supplied with the trainer) mustbeconnectedto DC Battery IN terminals (+ and -), available on the right side, accordingto the polarity. The batteryvoltageshallbeindispensable for all the componentsthatrequirepowersupply (sensors and fuelcell controller) and shallbeinterruptedacting on the on/off Batteryswitch.
The FC terminals (FC+ and FC-) and the LOAD terminals (LOAD+ and LOAD-) shallbe alsoavailable on the module and identifiedrespectivelybyFuelCell OUT (+ and -) and Load(+ and -); the FuelCell OUT terminalsshallbetakendirectlyfromthoseavailable on the fuelcellbut theLoadterminalsshallbe takenfrom the fuelcell controller.
PEM fuelcellshallhave the followingfeatures:
- PEM fuelcell with air cooling and electronic controlincluding a battery of 24 elements
- Nominalpower: 100W
- Peakpower: 102W
- Performance: 14V at 7.2A
- Reagents: Hydrogen and air
- External temperature: from 5 to 40°C
- Maximum temperature shutdown of the cell: 65°C
- Maximumcurrentshutdown of the cell: 12A
- Maximumhydrogenpressurebefore the pressureregulator: 8 – 10bar
- Maximumhydrogenpressure at cellstack (after the pressureregulator): 0.4 – 0.5bar
- Minimum purity H2 gas supply: grade 4.5 (99.995%) dry
- Humidification: self-humidifying
- Cooling: air (integrated fan)
- Fuelcelltype: PEM
- Consumption at maximumpower: 1.4L/min
- Power on time: 2 – 3s
- FuelCell efficiency: 40% at 12V.
Itmustbesuppliedby the Batterymodule; italsoshallhave a switchtodisconnectthe modulewhennot in use, leaving the connectionsintact.
Thismodulemustinclude sixdigitalinstruments:
- H2 pressureinstrumentto monitor the hydrogenpressurereaching the PEM fuelcellthrough the pressuretransducer; asmentionedbefore the input terminals +/-, placed at the left of the instrument, mustbeconnectedtoPressureSensor OUT; the measuredvalueshall besimplycomparedto the valueindicated on the BourdonPressureGauge at the output of the pressureregulator. The unit of measurementshallbembar.
- H2 flow instrumentto monitor the hydrogen flow reaching the PEM fuelcellthroughthe flow sensor; for thisinstrumentalso, the input terminals +/-, placed at the left of the instrument, mustbeconnectedto Flow Sensor OUT; the unit of measurementshallbe ml/min.
- FuelCell Temperature instrumentto monitor the temperature of the outercasing of the fuelcell and also the room temperature if the cellisnotoperating; the input terminals +/-,placed at the left of the instrument, mustbeconnectedtoTemp. Sensor OUT;
the unit of measurementshallbe °C. For the internal temperature monitoring, the system shallbe supplied with a T sensorlocated inside fuelcell controller.
- Voltageinstruments (2 units, for Load and for FuelCell) tomeasure the voltagesdeliveredby the fuelcell and suppliedto the loaddirectly or through a DC/DC converter. Their input terminals +/-, placed at the right of the instruments, shall beconnectedto Full Cell OUT
and Loadbut the usercouldalsousethemasvoltmeters (with full scale of 40Vdc) tomeasureothervariables in the laboratory; the unit of measurementshallbe V.
- Current instrumenttomeasure the currentflowingthrough the loadconnectedto the fuel
cell output or to the DC/DC converter; the input terminals +/-, placed at the right of the instrument, mustbeconnected in seriesto the selectedload (the full scale is 10A).
DC/DC convertermodule
Thismoduleshall include a DC/DC converterusefultoconvertpowerfromone DC voltage source toanother DC voltage.
Itshallbe a regulateddevice, taking a possiblyvarying input voltage, and providing a stable, regulated output voltage, up to a design current (amperage) limit.
Itshallbe a step-down DC to DC convertercalledalso ‘buck’ converter.
Thismodulemusthave the followingspecifications:
Input voltage: 9 ÷ 36 Vdc
Output Voltage: 12 Vdc
Output Current: Min. 0 mA Max. 8.3°
Input Current: No Load: 35 mA Full Load: 4902 mA
% Efficiency: 85
Lampsloadmodule:
Thismoduleshall include twolamps with theirrespectiveswitches and terminals; the upper oneshallbeanhalogenlamp (12V, 20W) and the loweroneshallbe a LED lamp (12V, 3x1W). The reason of a red terminal for the halogenlampshallbetorespect the polarityfor supplyingalso a little fan, internallyconnectedto the lamp, and servestocoolwhenitisusedas a load for a long
time.
Variablerheostatmodule
Thismoduleshallbe a variablelogarithmicrheostat.
Valuesrange: from 1.5 Ω toabout 17 Ω
Maximumcurrent: 8A
Maximumpower: 100W
Batterymodule
Lead Acid batteryuniversal;
Voltage: 12V;
Capacity: 7.2Ah.
With this trainer itmustbepossibletoperform the followingexperiments:
Performance of the PEM FuelCell with fixedloads, withoutDC/DC Converter
Performance of the PEM FuelCell with fixedloads, withDC/DC Converter
Recording of the Current/VoltageCharacteristic curve of the PEM FuelCell with variableload
Calculation of the Energetic Efficiency of the PEM FuelCell