Page 24 - Fuel Cell Student Edition
P. 24
Where: Where:
PE = potential energy of the rover E = the total mechanical energy needed
interval
in each interval to move the rover
m = mass of the rover
from one point to the next
g = gravitational acceleration of the moon
PE interval = potential energy for the interval
h = height of the rover relative to the
last point KE interval = kinetic energy for the interval
Er = the energy required to overcome the
rolling resistance between two points
The kinetic energy of the rover is:
The electrical to mechanical energy conversion
process is 82% efficient. To find the equivalent
electrical energy to be supplied by the fuel cell, use
the following equation:
Where:
E interval
KE = kinetic energy of the rover EE interval =
Efficiency
m = mass of the rover
v = velocity of the rover Where:
EE interval = electrical energy required in the
The rolling energy loss is: interval
E = the total mechanical energy in each
interval
interval
Efficiency = 82% electrical to mechanical
Where: conversion efficiency
m = mass of the rover
The fuel cell provides a constant rate of power
g = gravitational acceleration of the moon
delivery. To compute the energy delivered by the
µ = coefficient of friction between rover fuel cell in each interval, use the following formula:
wheel and moon
t
s = distance traveled by the rover E fuel cell = P fuel cell * interval
in this interval
Where:
= slope of the terrain at the rover
E = the energy delivered by the fuel cell
fuel cell
in the interval
The total energy in each interval can now be
calculated by summing all of the energies needed: P fuel cell = the power delivered during the
interval by the fuel cell
E = PE + KE + E t = the time interval between two points
interval interval interval r interval
24 TOTAL REDOX™ – FUEL CELLS TOTAL REDOX™ – FUEL CELLS 25
