Sunday, December 28, 2008

Stove Types and Keys to Efficient Heating

Wood burning stoves can be classified generally into three kinds:
1. free-standing fireplaces in which the atmosphere of an open fireplace is the most important feature,
2. enclosed fireboxes which are used primarily for heaters, and
3. cook stoves which are used for some heating as well.
Some stoves are combination fireplaces and heaters. In the US, the well-known Franklin fireplace is he best known example of this type.

The free-standing fireplace that is sold as decorative furniture and for warmth and atmosphere is usually not chosen for utilitarian reasons. However, a room can be warmed b these fireplaces especially if the fireplace is constructed of metal which will radiate heat into the room. The Franklin fireplace can be closed to improve somewhat the heating capacity. Unfortunately the firebox of the Franklin stove is not tight enough to control the flow of air for efficient wood operation.

For efficient and economical heating, three design criteria are important:
1. the stove should have a tight firebox with an adjustable draft to ensure the wood to burn slowly.
2. there should be a large mass of cast iron to collect the heat and radiate it into the room, and
3. the stove should be designed so that baffles and heating chambers direct smoke through the stove to achieve as much heat transfer to the stove surfaces as possible rather than have most the heat lost up the chimney.

The quality of wood burning stoves in an important criterion.Cast iron stoves are not only better than sheet metal stoves because they give a more even heat, but also because the sheet metal suffers from metal fatigue if stressed by repeated opening and closing of doors and vents. Some stoves are available which are enamel on top of cast iron. The enameling is much easier to clean than is cast iron and it is not necessary to use stove black to keep the stove attractive.

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