Answer:
The efficiency of this fuel cell is 80.69 percent.
Explanation:
From Physics we define the efficiency of the automotive fuel cell (
), dimensionless, as:
(Eq. 1)
Where:
- Maximum power possible from hydrogen flow, measured in kilowatts.
- Output power of the automotive fuel cell, measured in kilowatts.
The maximum power possible from hydrogen flow is:
(Eq. 2)
Where:
- Volume flow rate, measured in cubic meters per second.
- Density of hydrogen, measured in kilograms per cubic meter.
- Heating value of hydrogen, measured in kilojoules per kilogram.
If we know that
,
,
and
, then the efficiency of this fuel cell is:
(Eq. 1)
![\dot W_{in} = \left(\frac{28}{3600}\,\frac{m^{3}}{s}\right)\cdot \left(0.0899\,\frac{kg}{m^{3}} \right)\cdot \left(141790\,\frac{kJ}{kg} \right)](https://tex.z-dn.net/?f=%5Cdot%20W_%7Bin%7D%20%3D%20%5Cleft%28%5Cfrac%7B28%7D%7B3600%7D%5C%2C%5Cfrac%7Bm%5E%7B3%7D%7D%7Bs%7D%5Cright%29%5Ccdot%20%5Cleft%280.0899%5C%2C%5Cfrac%7Bkg%7D%7Bm%5E%7B3%7D%7D%20%5Cright%29%5Ccdot%20%5Cleft%28141790%5C%2C%5Cfrac%7BkJ%7D%7Bkg%7D%20%5Cright%29)
![\dot W_{in} = 99.143\,kW](https://tex.z-dn.net/?f=%5Cdot%20W_%7Bin%7D%20%3D%2099.143%5C%2CkW)
(Eq. 2)
![\eta = \frac{80\,kW}{99.143\,kW}](https://tex.z-dn.net/?f=%5Ceta%20%3D%20%5Cfrac%7B80%5C%2CkW%7D%7B99.143%5C%2CkW%7D)
![\eta = 0.807](https://tex.z-dn.net/?f=%5Ceta%20%3D%200.807)
The efficiency of this fuel cell is 80.69 percent.