Environmental Engineering Reference
In-Depth Information
maximum height of blast furnaces (about 7.5 m by 1750)
was limited not only by charcoal's friability but also by the
maximum air blast available from water-powered bellows.
Both these limits were removed once coal was turned to
coke (capable of supporting heavy charges) and con-
verted to mechanical energy in steam engines.
Biomass fuels were also the principal provider of tradi-
tional lighting, beginning with fire glow and inefficient
(and dangerous) resinous torches. The first oil lamps
appeared in Europe during the Upper Paleolithic, nearly
40,000 years ago (de Beaune and White 1993); the first
candles were used in the Middle East only after 800
B
.
C
.
E
. Both were inefficient, weak, and smoky sources of
light, but they were easily portable. Various plant oils and
animal fats (olive, castor, rapeseed, linseed, whale oil,
beef tallow, beeswax) provided the fuel, and wicks were
made of papyrus, rush pith, flaxen, or hemp. Bright illu-
mination was possible only through massive multiplica-
tion of these tiny and inefficient sources. Paraffin candles
convert just 0.01% of energy in solid hydrocarbons to
light and emit only about 0.1 lumen/W. The bright
spot in their flame has irradiance only 20% higher than
clear sky (1.0 Cd/cm
2
vs. 0.8 Cd/cm
2
). The first
eighteenth-century lighting innovations doubled and
tripled the typical irradiance. In 1794, Aime Argand
introduced lamps that could be regulated for maximum
luminosity using wick holders with central air supply and
chimneys to draw in the air (McCloy 1952).
Soon afterward came the first lighting gas made from
coal; Paton (1890) calculated that gas jets converted less
than 0.04% of that fuel to light. Outside major cities oil
lamps were dominant during the entire nineteenth cen-
tury. Until the 1860s they were fueled by an exotic bio-
mass fuel, oil rendered onboard ships from the blubber
of sperm whales. The poorly paid and dangerous pursuit
of these giant mammals, portrayed so unforgettably in
Melville's Moby-Dick (1851), reached its peak just before
1850 (Francis 1990). The U.S. whaling fleet, by far the
largest in the world, had a record total of more than
700 vessels in 1846. During the first half of that decade
about 160,000 barrels of sperm oil were brought each
year to New England's ports (Starbuck 1878). The sub-
sequent decline of sperm whale numbers, and competi-
tion from coal gas and kerosene, led to a rapid demise of
the hunt.
7.4 Construction: Methods and Structures
Timber, stone, and bricks, either sun-dried or kiln-
burned, were the dominant building materials of the
preindustrial world, all suitable to construct the four
components (walls, columns, beams and arches) that are
needed to erect structures whose dimensions were sur-
passed only by the advent of inexpensive structural steel
and modern concrete during the late nineteenth century.
Only animate labor aided by a few simple tools was
needed to extract, transport, shape, and emplace these
materials. Sun-dried mud bricks, made of compacted
mixtures of clays, water and chaff, or chopped straw and
shaped in wooden molds, were the least energy-intensive
building material. Fired bricks were used first in ancient
Mesopotamia, and later they were common in both the
Roman Empire and Han China. Their firing in open piles
or pits was extremely wasteful, and only enclosed kilns,
with regularly spaced flues, eventually resulted in more
even baking and lower fuel consumption. The dimen-
sions of fired bricks ranged from chunky square Babylo-
nian pieces (40
40
10 cm) to slim oblong Roman
shapes (45
30
3
:
75 cm).
