Page 271 - Alternative Energy Systems in Building Design

FUEL CELL DESIGN 247

BACKING LAYER
HYDROGEN GAS
OXIDANT FLOW FIELD
HYDROGEN FLOW FIELD
OXIDANT

WATER
CATHODE (−)
UNUSED FUEL
ANODE (+) POLYMER ELECTROLYTE
MEMBRANE
Figure 7.1 Diagram of a proton exchange membrane fuel cell.

FUEL CELL DESIGN ISSUES

One of the most important issues in fuel cell design is internal water and heat control.
As mentioned earlier, the chemical reaction between the reactants and oxidants
produces waste water and a significant amount of heat, both of which must be con-
trolled and regulated. Otherwise, fuel cell operation cannot be sustained for extended
periods of time. Figure 7.3 presents a cross section of a fuel cell.

GOLD WIRE USED FOR CURRENT EXTRACTION
AIR CHANNEL WALL
PEMFC

WATER INFLOW WATER OUTFLOW

Figure 7.2 Flow diagram of a fuel cell water-extraction channel.