Page 328 - Synthetic Fuels Handbook

314 CHAPTER TEN

of the heat of the fire and exhaust in a large thermal mass, becoming much more efficient
than a fireplace alone.
The metal stove was a technologic development concurrent with the industrial revolu-
tion. Stoves were manufactured or constructed pieces of equipment that contained the fire
on all sides and provided a means for controlling the draft—the amount of air allowed to
reach the fire. Stoves have been made of a variety of materials. Cast iron is among the more
common. Soapstone (talc), tile, and steel have all been used. Metal stoves are often lined
with refractory materials such as firebrick, since the hottest part of a wood-burning fire will
burn away steel over the course of several years’ use.
The Franklin stove was developed in the United States by Benjamin Franklin. More a
manufactured fireplace than a stove, it had an open front and a heat exchanger in the back
that was designed to draw air from the cellar and heat it before releasing it out the sides.
The heat exchanger was never a popular feature and was omitted in later versions. So-called
“Franklin” stoves today are made in a great variety of styles, though none resembles the
original design.
The airtight stove, originally made of steel, allowed greater control of combustion,
being more tightly fitted than other stoves of the day. Airtight stoves became common in
the nineteenth century.

Fuel Wood. Fuel wood (i.e., wood itself) is the most common solid fuel and continues
to be widely used as a major source of energy for households, especially in developing
countries. Charcoal is also increasingly used in many African countries by urban dwell-
ers, as a result of a relentless process of migration of people from rural areas toward urban
centers. The major energy end-use in households is cooking: about 86 percent of fuel wood
consumed in urban households in India is for this purpose, while the rest is mostly used
for water heating. In Africa, more than 86 percent of total wood fuels consumption was
attributed to the household sector in 1994. Dependence on wood fuels to meet household
energy needs is especially high in most of sub-Saharan Africa, where 90 to 98 percent of
residential energy consumption is met from this source.
In short, the use of fuel wood and charcoal remains the dominant source of energy for
most developing countries. It is estimated that over 2 billion poor people depend on fuel
wood and/or charcoal for meeting their basic daily energy needs for cooking and heat-
ing. For them, wood fuels are not only vital to the nutritional stability of rural and urban
households, but are also often essential in food-processing industries for baking, brewing,
smoking, curing, and electricity production.
In places with high fuel wood and charcoal consumption (due to high population
density with low income and/or severe climatic conditions) and weak supply sources,
strong pressures are put on existing tree resources, and deforestation and devegetation
problems remain a matter of great concern. In addition, urbanization and economic devel-
opment are bringing about changes in consumption patterns in developing countries,
which in turn are leading to major changes in the household energy sector. A pronounced
shift from fuel wood to charcoal, especially in Africa, is observed. This issue has raised
concerns among environmentalists and those responsible for forest development and
management because these charcoal-making activities are, in most cases, carried out
illegally. Moreover, they put a much higher pressure on natural forests than the extraction
of fuel wood, which is often produced from trees outside forests or from other sources
not involving the destruction of forests.
In developed countries, heat production by households also remains the major use of
fuel wood. For instance, in the European Union wood fuels account for around 60 percent
of the total wood energy consumed, although their utilization as an industrial energy source
for electricity and heat generation is increasing, as a result of new energy policies enacted
in most countries to comply with climate change mitigation programs.