燃料电池及应用
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Eg., combustion of natural gas (methane 甲烷):
CH 4 2O2 CO2 2H 2O
A mole (16 grams) of methane can produce 890 kJ of energy (chemical energy) when combusted. Q: How much of water can be heated up from 20 to 40 C?
Chapter 1
5
ቤተ መጻሕፍቲ ባይዱ
2 What is a Fuel Cell?
A fuel cell is defined as a device which can directly convert chemical energy into electricity through an electrochemistry process.
Chapter 1
3
1 Why Fuel Cells?
•Limitation of energy resources: Coal resources can last ~100 years while petroleum can last ~40 years – we are running out of the energy resources. •Environment changes and pollution: Exhaust of carbon dioxide – green house effect, air pollution. •Quest for convenient, safe, and stable energy applications – eg., a handy, non-explosive, and recharge-free battery for cell phones, personal PCs. •Quest for un-centralized, mobile, smaller-capacity electricity generation.
Indirect conversion: heat engine.
fuel
heat
doing work
(combustion) (heat engine)
The efficiency of a heat engine is limited by
Carnot cycle.
Direct conversion: animal digestion, fuel cells.
Chapter 1
4
Fuel Cells offer:
•A reliable source of energy supply so long as the fuel is available. •A quiet power generation – no moving parts such as engine. •A high efficiency of energy conversion – fuel cell can reach an efficiency of 70% while a Rankine cycle reaches ~35%. •Nearly zero emission – hydrogen fuel cells produce only water.
food, fossil fuel
energy, electricity
(digestion, electrochemistry)
Chapter 1
6
Chapter 1
7
What is chemical energy?
Chemical energy is the maximum energy we can obtain from a chemical compound.
Fuel Cells and Applications
S. K. Wang Dept. of Mechanical and Automation Engineering
I – Shou University Spring, 2005
Chapter 1
1
Topics:
1. Introduction, Basic Principles 2. Efficiency and Open Circuit Voltage, Electrochemistry
Chapter 1
8
Conventional fossil-fueled power plant can only convert ~30% of the chemical energy of the fuel into electricity.
Conventional power plant:
chemical energy heat shaft work electricity
of Fuel Cells 3. Operational Fuel Cell Voltages – Real Cell Voltages 4. Proton Exchange Membrane Fuel Cells (PEMFC) 5. Alkaline Electrolyte Fuel Cells (AFC) 6. Medium and High Temperature Fuel Cells (PAFC,
MCFC, and SOFC) 7. Fueling Systems 8. Engineering Components of Systems
Chapter 1
2
•Why fuel cells? •What is a fuel cell? •How does a fuel cell work? •What are concepts of “fuel” and “cell”? •What are the characteristics of fuel cell systems? •What kinds of fuel cells are under developing? •What are the applications of fuel cells?
CH 4 2O2 CO2 2H 2O
A mole (16 grams) of methane can produce 890 kJ of energy (chemical energy) when combusted. Q: How much of water can be heated up from 20 to 40 C?
Chapter 1
5
ቤተ መጻሕፍቲ ባይዱ
2 What is a Fuel Cell?
A fuel cell is defined as a device which can directly convert chemical energy into electricity through an electrochemistry process.
Chapter 1
3
1 Why Fuel Cells?
•Limitation of energy resources: Coal resources can last ~100 years while petroleum can last ~40 years – we are running out of the energy resources. •Environment changes and pollution: Exhaust of carbon dioxide – green house effect, air pollution. •Quest for convenient, safe, and stable energy applications – eg., a handy, non-explosive, and recharge-free battery for cell phones, personal PCs. •Quest for un-centralized, mobile, smaller-capacity electricity generation.
Indirect conversion: heat engine.
fuel
heat
doing work
(combustion) (heat engine)
The efficiency of a heat engine is limited by
Carnot cycle.
Direct conversion: animal digestion, fuel cells.
Chapter 1
4
Fuel Cells offer:
•A reliable source of energy supply so long as the fuel is available. •A quiet power generation – no moving parts such as engine. •A high efficiency of energy conversion – fuel cell can reach an efficiency of 70% while a Rankine cycle reaches ~35%. •Nearly zero emission – hydrogen fuel cells produce only water.
food, fossil fuel
energy, electricity
(digestion, electrochemistry)
Chapter 1
6
Chapter 1
7
What is chemical energy?
Chemical energy is the maximum energy we can obtain from a chemical compound.
Fuel Cells and Applications
S. K. Wang Dept. of Mechanical and Automation Engineering
I – Shou University Spring, 2005
Chapter 1
1
Topics:
1. Introduction, Basic Principles 2. Efficiency and Open Circuit Voltage, Electrochemistry
Chapter 1
8
Conventional fossil-fueled power plant can only convert ~30% of the chemical energy of the fuel into electricity.
Conventional power plant:
chemical energy heat shaft work electricity
of Fuel Cells 3. Operational Fuel Cell Voltages – Real Cell Voltages 4. Proton Exchange Membrane Fuel Cells (PEMFC) 5. Alkaline Electrolyte Fuel Cells (AFC) 6. Medium and High Temperature Fuel Cells (PAFC,
MCFC, and SOFC) 7. Fueling Systems 8. Engineering Components of Systems
Chapter 1
2
•Why fuel cells? •What is a fuel cell? •How does a fuel cell work? •What are concepts of “fuel” and “cell”? •What are the characteristics of fuel cell systems? •What kinds of fuel cells are under developing? •What are the applications of fuel cells?