Environmental Engineering Reference
In-Depth Information
9
Hydrogen Utilization: Fuel Cells
9.1 BASICS OF FUEL CELLS
9.1.1 The Rational Development of Fuel Cells
Hydrogen has the highest energy content by weight (33,320 Wh·kg
−1
), which
is about 2.6 and 2.4 times more than gasoline (12,700 Wh·kg
−1
) and natural
gas (13,900 Wh·kg
−1
), respectively [1-3]. In Chapter 8, we have reviewed
hydrogen utilization for direct combustion. However, the efficiency of a
hydrogen internal combustion engine (ICE) is ca. 25% while that of a hydro-
gen fuel cell vehicle is 60%, which is three times better than that of petrol-
fuelled engines (18-20% for a petrol ICE reaching 40% at peak efficiency)
[4, 5].
In this chapter, we will discuss the application of hydrogen in fuel cells.
A fuel cell is a device that converts chemical energy supplied as input fuels
into electric energy, and is essentially a battery with an external fuel source
[5]. It creates electricity by stripping electrons off the hydrogen. Like a
battery, a typical fuel cell contains a set of plates for electrochemical reac-
tions [6]. Unlike a battery, it never runs out and it produces a continuous
flow of clean power as long as fuel is supplied. The invention of fuel cells
as energy conversion systems dates back from the middle of the nineteenth
century by Sir William Grove, “father of the fuel cell.” However, the principle
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