Stove - AbsoluteAstronomy.com

A stove is an enclosed heated space. The term is commonly taken to mean an enclosed space in which fuel is burned to provide heating, either to heat the space in which the stove is situated or to heat the stove itself, and items placed on it. This article is principally concerned with enclosed stoves burning solid fuels for room heating.

Origin

The Old English word stofa meant any individual enclosed space, such as a room, and 'stove' is still occasionally used in that sense, as in 'stoved in'. Until well into the 19th century 'stove' was used to mean a single heated room, so that Joseph Banks

Joseph Banks

Sir Joseph Banks, 1st Baronet, GCB, PRS was an English naturalist, botanist and patron of the natural sciences. He took part in Captain James Cook's first great voyage . Banks is credited with the introduction to the Western world of eucalyptus, acacia, mimosa and the genus named after him,...

assertion that he 'placed his most precious plants in the stove' or René Descartes

René Descartes

René Descartes ; was a French philosopher and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day...

observation that he got 'his greatest philosophical inspiration while sitting inside a stove' are not as odd as they seem.

In its earliest attestation, cooking was done by roasting meat and tubers in an open fire. This form of cooking is still the mainstay of groups such as the Hadza. Pottery and other cooking vessels may be placed directly on such a fire, but setting the vessel on a support resulted in a stove, the simplest of which is a base of three stones. The three-stone stove is still widely used around the world. In some areas it developed into a U-shaped dried mud enclosure with the opening in the front for fuel and air, sometimes with a second smaller hole at the rear.

Kitchen stove

A kitchen stove, cooker, or cookstove is a kitchen appliance designed for the purpose of cooking

Cooking

Cooking is the process of preparing food by use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training...

food. Kitchen stoves rely on the application of direct heat for the cooking process and may also contain an oven

Oven

An oven is a thermally insulated chamber used for the heating, baking or drying of a substance. It is most commonly used for cooking. Kilns, and furnaces are special-purpose ovens...

underneath it which is used for baking

Baking

Baking is the technique of prolonged cooking of food by dry heat acting by convection, and not by radiation, normally in an oven, but also in hot ashes, or on hot stones. It is primarily used for the preparation of bread, cakes, pastries and pies, tarts, quiches, cookies and crackers. Such items...

Coal stoves

The most common stove for heating in the industrial world for almost a century and a half was the coal stove that burned coal. Coal stoves came in all sizes and shapes and different operating principles. Coal burns at a much higher temperature than wood, and coal stoves must be constructed to withstand the high heat levels. A coal stove can burn either wood or coal, but a wood stove can not burn coal. While a given amount of coal gives up more heat than the same weight of wood, coal stoves have largely been abandoned because of environmental concerns.

Efficiency

Enclosed stoves hold out the possibility of greater efficiency, controllability and lower smoke emission than simple open fires. In free air solid fuels burn at a temperature of only about 240 °C (464 °F), which is too low a temperature for perfect combustion reactions to occur, heat produced through convection

Convection

Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....

is largely lost, smoke

Smoke

Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires , but may also be used for pest...

particles are evolved without being fully burned and the supply of combustion air cannot be readily controlled.

By enclosing the fire in a chamber and connecting it to a chimney, draft (draught) is generated pulling fresh air through the burning fuel. This causes the temperature of combustion to rise to a point (600 °C (1,112 °F)) where efficient combustion is achieved, the enclosure allows the ingress of air to be regulated and losses by convection are almost eliminated. It also becomes possible, with ingenious design, to direct the flow of burned gasses inside the stove such that smoke particles are heated and destroyed.

Enclosing a fire also prevents air from being sucked from the room into the chimney. This can represent a significant loss of heat as an open fireplace can pull away many cubic metres of heated air per hour.

An early improvement was the fire chamber: the fire was enclosed on three sides by masonry walls and covered by an iron plate. Only in 1735 did the first design that completely enclosed the fire appear: the Castrol stove of the French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

architect

Architect

An architect is a person trained in the planning, design and oversight of the construction of buildings. To practice architecture means to offer or render services in connection with the design and construction of a building, or group of buildings and the space within the site surrounding the...

François Cuvilliés was a masonry construction with several fireholes covered by perforated iron plates. It is also known as a stew stove. Near the end of the 18th century, the design was refined by hanging the pots in holes through the top iron plate, thus improving heat efficiency even more.
In 1742, Benjamin Franklin

Benjamin Franklin

Dr. Benjamin Franklin was one of the Founding Fathers of the United States. A noted polymath, Franklin was a leading author, printer, political theorist, politician, postmaster, scientist, musician, inventor, satirist, civic activist, statesman, and diplomat...

patented an all-metal stove

Franklin stove

The Franklin stove is a metal-lined fireplace named after its inventor, Benjamin Franklin. It was invented in 1741.L.W. Labaree, W. Bell, W.B. Willcox, et al., eds., The Papers of Benjamin Franklin , vol. 2, page 419...

in an attempt to improve efficiency.

Some stoves use a catalytic converter which causes combustion of the gas and smoke particles not previously burned. Other models use a design that includes firebox insulation, a large baffle to produce a longer, hotter gas flow path. Modern enclosed stoves are often built with a window to let out some light and to enable the user to view progress of the fire.

While enclosed stoves are typically more efficient and controllable than open fires, there are exceptions. The type of water-heating 'back boiler

Back boiler

A back boiler is a device which is fitted to a residential heating stove or open fireplace to enable it to provide both room heat and domestic hot water or central heating...

' open fires commonly used in Ireland, for instance, can be more than 80% absolute efficiency, while the type of enclosed stove commonly used in China may be less than 15% efficient.

Material

Masonry heater

A masonry heater is a device for warming a home that captures the heat from periodic burning of fuels , and then radiates that heat over a long period at a fairly constant temperature. The technology exists in many forms from the Roman hypocaust to the Austrian/German kachelofen...

s were developed to control air flow in stoves. A masonry heater is designed to allow complete combustion by burning fuels at full-temperature with no restriction of air inflow. Due to its large thermal mass the captured heat is radiated over long periods of time without the need of constant firing, and the surface temperature is generally not dangerous to touch.

Metal stoves came into use in the 18th century. An early, and famous, example of a metal stove is the Franklin stove

Franklin stove

, said to have been invented by Benjamin Franklin

Benjamin Franklin

in 1742. It had a labyrinthine path for hot exhaust gases to escape, thus allowing heat to enter the room instead of going up the chimney. The Franklin stove, however, was designed for heating, not for cooking. Benjamin Thompson

Benjamin Thompson

Sir Benjamin Thompson, Count Rumford , FRS was an American-born British physicist and inventor whose challenges to established physical theory were part of the 19th century revolution in thermodynamics. He also served as a Lieutenant-Colonel in the Loyalist forces in America during the American...

at the turn to the 19th century was among the first to present a working metal kitchen stove. His Rumford fireplace

Rumford fireplace

The Rumford fireplace is a tall, shallow fireplace designed by Sir Benjamin Thompson, Count Rumford, born 1753 in Woburn, Massachusetts, an Anglo-American physicist who was known for his investigations of heat....

used one fire to heat several pots that were also hung into holes so that they could be heated from the sides, too. It was even possible to regulate the heat individually for each hole. His stove was designed for large canteen or castle kitchens, though. It would take another 30 years until the technology had been refined and the size of the iron stove been reduced enough for domestic use. Philo Stewart's Oberlin stove was a much more compact, wood-burning cast-iron stove, patented in the U.S.

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

in 1834. It became a huge commercial success with some 90,000 units sold in the next 30 years. In Europe, similar designs also appeared in the 1830s. In the following years, these iron stoves evolved into specialised cooking appliances with flue pipes connected to the chimney, oven holes, and installations for heating water. The originally open holes into which the pots were hung were now covered with concentric iron rings on which the pots were placed. Depending on the size of the pot or the heat needed, one could remove the inner rings.

Modern stove designs

As concerns about air pollution, deforestation, and climate change have increased, new efforts have been made to improve stove design. The largest strides have been made in innovations for biomass burning stoves, such as the wood burning stoves used in many of the most populous countries. These new designs address the fundamental problem that wood and other biomass fires inefficiently consume large amounts of fuel to produce relatively small amounts of heat, while producing fumes that cause significant indoor
and environmental pollutants. The World Health Organization has documented the significant number of deaths caused by smoke from home fires. Increases in efficiency mean that a stove's users can spend less time gathering wood or other fuels, suffer less emphysema and other lung diseases prevalent in smoke-filled homes, while reducing deforestation and air pollution.

Corn and pellet stoves and furnaces

Pellet stove

A pellet stove is a stove that burns compressed wood or biomass pellets to create a source of heat for residential and sometimes industrial spaces...

are a type of biofuel stove. The shelled dry kernel of corn, also called a corn pellet, creates as much heat as a wood pellet but generates more ash. "Corn pellet stoves and wood pellet stoves look the same from the outside. Since they are highly efficient, they don't need a chimney; instead they can be vented outdoors by a four-inch (102 mm) pipe through an outside wall and so can be located in any room in the home."

A pellet stove uses small, biological fuel pellets which are renewable and very clean-burning. Home heating using a pellet stove is an alternative currently used throughout the world, with rapid growth in Europe. The pellets are made of renewable material –- typically wood sawdust or off-cuts. There are currently more than half a million homes in North America using pellet stoves for heat, and probably a similar number in Europe. The pellet stove typically uses a feed screw to transfer pellets from a storage hopper to a combustion chamber. Air is provided for the combustion by an electric blower. The ignition is automatic, using a stream of air heated by an electrical element. The rotation speed of the feeder and the fan speeds can be varied to modulate the heat output.

Other efficient stoves are based on Top Lit updraft (T-LUD) or Woodgas or Smoke Burner stove a principle applied and made popular by Dr. Thomas Reed, which use small pieces of sticks, chips of wood or shavings, leaves, etc., as fuel. The efficiency is very high up to 50 percent as compared to traditional stoves which are 5 to 15 percent on an average.

Air-tight stove

An air-tight stove is a wood-burning stove

Wood-burning stove

For a list of stove types see Stove .A wood-burning stove is a heating appliance capable of burning wood fuel and wood-derived biomass fuel. Generally the appliance consists of a solid metal closed fire chamber, a grate and an adjustable air control...

designed to burn solid fuel, traditionally wood, in a controlled fashion so as to provide for efficient and controlled fuel use, and the benefits of stable heating or cooking temperatures. They are made of sheet metal, consisting of a drum-like combustion chamber with airflow openings that can be open and shut, and a chimney of a metre or more length that turns from vertical to horizontal so as to leave the tent or building by a side wall rather than the roof.

These stoves are used most often to heat tents and buildings in winter. Wood or other fuel is put into the stove, lit, and then air flow is regulated to control the burn. The intake airflow is either at the level where fuel is added, or below it. The exhaust (smoke) from the stove is usually several metres above the combustion chamber. This arrangement provides for regulation of the intensity of fire by limiting air flow, and for the fire to create a strong draught or draw up the chimney. This results in highly efficient fuel usage. They are a more sophisticated and traditional version of wood burning rocket stove

Rocket stove

A rocket stove is an innovative clean and efficient cooking stove using small diameter wood fuel which is burned in simple high-temperature combustion chamber containing an insulated vertical chimney which ensures complete combustion prior to the flames reaching the cooking surface. The principles...

s. With the advent of new tent fabrics, they have fallen out of favour because substituting nylon for canvas creates fire hazards.

Emissions

Many countries legislate to control emissions. In the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the Environmental Protection Agency

United States Environmental Protection Agency

The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

created stricter emissions standards in the late 1980s. Maximum smoke output is limited to 7.5 grams per hour.

The burn temperature in modern stoves can increase to the point where secondary and complete combustion of the fuel takes place. A properly fired masonry heater has little or no particulate pollution in the exhaust and does not contribute to the buildup of creosote

Creosote

Creosote is the portion of chemical products obtained by the distillation of a tar that remains heavier than water, notably useful for its anti-septic and preservative properties...

in the heater flues or the chimney. Some stoves achieve as little as 1 to 4 grams per hour. This is roughly 90% less smoke than older stoves, and equates to nearly zero visible smoke from the chimney. This is largely achieved through causing the maximum amount of material to combust, which results in a net efficiency of 60 to 70% as contrasted to less than 30% for an open fireplace. (Net efficiency is the amount of heat energy transferred to the room compared to the amount contained in the wood, minus any amount central heating must work to compensate for airflow problems.)

Stove research and development

The search for safer, cleaner stoves remains to many an important if low-profile area of modern technology. Stoves in common use around the world, particularly in Third World countries, are considered fire hazards and worse: according to the World Health Organization

World Health Organization

The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

, a million and a half people die from indoor smoke inhalation caused by faulty stoves. An engineer's "Stove Camp" has been hosted every year since 1999 by Aprovecho Research Center (Oregon, US) with the intent of designing a cheap, efficient, and healthy stove for use around the world. Other engineering societies (see Envirofit

Envirofit

Envirofit International is a nonprofit project that develops technology that reduces pollution and enhances energy efficiency in developing countries, particularly in Asia. Envirofit hopes that its endeavors will "promote environmental benefits, improve public health, foster economic growth, and...

, Colorado, US) and philanthropic groups (see the Gates Foundation, California, US) continue to research and promote improved stove designs.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.