TABLE OF CONTENTS Problem No. 1:
The average speed and power of an automotive fuel cell system over a 400-km range are 9m/s and 9kW, respectively, and the average fuel cell efficiency (LHV) during that ride is 53%. Calculate the amount of hydrogen that has to be stored onboard. What is the corresponding fuel efficiency (in miles per gallon of gasoline equivalent)?
Problem No. 2:
A power profile of a 75-kW fuel cell vehicle, and corresponding drive train efficiencies are given in the following table:
| Time | Power | Efficiency |
|---|---|---|
| 3.0% | 100.0% | 49% |
| 7.0% | 50.0% | 55% |
| 27.5% | 25.0% | 57% |
| 27.5% | 12.5% | 58% |
| 35.0% | 0% |
Calculate the average efficiency over such driving schedule for the following two cases:
During idle periods the fuel cell is shut off and does not consume any fuel.
During idle periods the fuel cell is kept running to supply the parasitic load, which is estimated at 2.5kW. The fuel cell efficiency during that period is 50%.
Problem No. 3:
From your home energy bills find the price of electricity and natural gas. Also find information on the heating fuel (electricity, natural gas, or heating oil). Estimate the payback time for a 5-kW fuel cell system that operates with 50% capacity factor and average efficiency of 35% with and without cogeneration (assume total efficiency of 75%). The fuel cell system costs $4400, including installation. How could the feasibility of this system be improved?
Problem No. 4:
A utility company pays $6 per 1000 cubic feet of natural gas and wants...
