Problem 2 Thermodynamics Properties Which of the following a

Problem 2 Thermodynamics Properties Which of the following are properties of the specified system? Which are not? System: An H2lAir Proton Exchange Membrane Fuel Cell (here is a short description: http://en.wikipedia.org/wiki/Fuel cell) a. volume of the fuel cell b. mass of the fuel cell c. pressure of the H2 gas in the fuel cell d. pressure of the air in the fuel cell e. water generated by the cell of the past year of operation f. work produced by the fuel cell over the past month g. voltage of the fuel cell h. entropy generated by the fuel cell i. heat transferred from the fuel cell to the environment over one minute j. date the fuel cell was assembled k. temperature of the fuel cell

Solution

1. VOLUME OF THE FUEL CELL- THIS IS THE PROPERTY OF FUEL CELL

- PROTON EXCHANGE MEMBRANE OR PEM FUEL CELLS ARE CONSIDERED TO BE THE MOST VERSATILE TYPE OF FUEL CELLS CURRENTLY IN PRODUCTION. THEY PRODUCE THE MOST POWER FOR A GIVEN WEIGHT OR VOLUME OF FUEL CELL. BECAUSE THEY ARE LIGHTWEIGHT, HAVE SUCH HIGH POWER DENSITY, AND COLD START CAPABILITY, THEY QUALIFY FOR MANY APPLICATIONS, SUCH AS STATIONARY POWER, TRANSPORT, PORTABLE POWER AND APPLICATION IN SPACE.

2. MASS OF THE FUEL CELL- THIS IS NOT THE PROPERTY OF FUEL CELL.

- IN THE FUEL CELL BASICALLY WE CONSIDER THE MASS OF ELECTROLYTES WHICH WE GONNA CONSUME TO PRODUCE ELECTRICITY SO IT IS NOT THE PROPERTY OF PEM FUEL CELL.

3. PRESSURE OF THE H2 GAS IN THE FUEL CELL.- THIS IS THE PROPERTY OF FUEL CELL

- PRESSURIZED HYDROGEN GAS (H₂) ENTERING THE FUEL CELL ON THE ANODE SIDE. THIS GAS I­S FORCED THROUGH THE CATALYST BY THE PRESSURE. WHEN AN H₂ MOLECULE COMES IN CONTACT WITH THE PLATINUM ON THE CATALYST, IT SPLITS INTO TWO H+ IONS AND TWO ELECTRONS (E-). THE ELECTRONS ARE CONDUCTED THROUGH THE ANODE, WHERE THEY MAKE THEIR WAY THROUGH THE EXTERNAL CIRCUIT (DOING USEFUL WORK SUCH AS TURNING A MOTOR) AND RETURN TO THE CATHODE SIDE OF THE FUEL CELL.

4. PRESSURE OF THE AIR IN THE FUEL CELL-THIS IS NOT THE PROPERTY OF FUEL CELL.

- AIR IS THE COMBINATION OF NITROGEN, OXYGEN AND MANY MORE GASSES. SO IN PEM FUEL CELL WE NEED PURE O2 GAS SO NO NEED OF AIR AND ITS PRESSURE.

5. WATER GENERATED BY THE CELL PAST OF THE OPERATION.- THIS IS THE PROPERTY OF FUEL CELL

- HYDROGEN IS THE FUEL CELL WHICH CONVERTS CHEMICAL ENERGY OF ELEMENTS IN TO THE ELECTRICITY AND WATER. THE OBTAINED ELECTRICITY IS STORED IN THE BATTERY AND AMMOUNT OF WATER IS IMMEDIATELY REMOVED FROM THE CELL.

6. WORK PRODUCED BY FUEL CELL OVER PAST MONTH- THIS IS THE PROPERTY OF FUEL CELL

- WORK PRODUCED BY FUEL CELL IS NOTHING BUT THE OUTPUT ENERGY AND OUTPUT OF FUEL CELL IS NOTHING BUT ELECTRICITY. WORK PRODUCED BY FUEL CELL=AMMOUNT OF ELECTRICITY GENERATED BY THE FUEL CELL.

7. VOLTAGE OF FUEL CELL- THIS IS THE PROPERTY OF FUEL CELL

- PEM FUEL CELL GENERATE THE AMMOUNT OF CIRCUIT VOLTAGE OF 1.18V. VOLTAGE IS GENERATED BECAUSE ELECTRON OF A HYDROGEN GAS GET EXCHANGED VIA PEM FUEL CELL. ELECTRON PASSING THROUGH THE CIRCIUT GENERATES THE VOLTAGE.

8. ENTROPY GENERATED BY FUEL CELL- THIS IS THE PROPERTY OF FUEL CELL

- THE ENTROPY GENERATED FOR THE FUEL CELL REACTION IS NEGATIVE.

9. HEAT GENERATED BY PEM FUEL CELL TO THE ENVIRONMENT OVER ONE MINUTE- THIS IS THE PROPERTY OF FUEL CELL

- HEAT GENERATED BECAUSE THE GIVEN REACTION IS THE EXOTHERMIC. GENERATED HEAT REALEASED TO ENVIRONMENT.

10. DATE WHEN THE FUEL CELL ASSEMBLED- THIS IS NOT THE PROPERTY OF FUEL CELL

11. TEMPERATURE OF FUEL CELL- THIS IS THE PROPERTY OF FUEL CELL