Environmental Engineering Reference
In-Depth Information
Process/technology
Conversion
Efficiency
Energy
loss
chemical
→
movement
Muscles
30%
heat
chemical
→
light
Candle
0.01%
heat
chemical
→
heat
Candle
99.99%
light
electric
→
light
Incandescent light bulb
10%
heat
electric
→
light
LED lamp
50%
heat
chemical
→
heat
→
movement
Steam engine
5%
heat,
noise
electric
→
movement
Electric engine
80%
heat,
noise
chemical
→
heat
→
movement
Car (internal combustion
engine)
10%
heat,
noise
chemical
→
heat
Gas turbine
> 95%
noise
chemical
→
heat
→
mechanical
Gas turbine
60%
heat,
noise
1.3 The Various Forms of Energy
Consider for a moment what it takes to read these lines. First, there is the energy required
to maintain a constant body temperature, then that used by the movement of the eye, and
finally the energy required by the brain to process the message. At no moment in our lives
do we cease to expend energy. Even during sleep the human body performs a variety of
tasks: the heart beats; blood circulates; enzymes and hormones digest, protect, repair, and
maintain temperature; and the brain, our most energy-intensive organ, works to maintain
control of the body. Like the human body, the world partakes in a constant exchange of
energy. It is, in the words of energy expert Vaclav Smil, “the only universal currency. One
