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The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions.
These are somewhat ideal values and the actual heat realized by any fuel will depend on the fireplace or combustion chamber used and its design for example. However they do give a useful guide to the heat available from any fuel. Dry wood has roughly two thirds the calorific value of coal so a greater weight is needed to make the same amount of ...
Firewood is any wooden material that is gathered and used for fuel. Generally, firewood is not heavily processed, and is in some sort of recognizable log or branch form, compared to other forms of wood fuel like pellets. Firewood can be seasoned and heat treated (dry) or unseasoned (fresh/wet). It is generally classified as either hardwood or ...
Note that the especially high molar values, as for paraffin, gasoline, water and ammonia, result from calculating specific heats in terms of moles of molecules. If specific heat is expressed per mole of atoms for these substances, none of the constant-volume values exceed, to any large extent, the theoretical Dulong–Petit limit of 25 J⋅mol ...
The energy content of wood pellets is approximately 4.7 – 5.2 MWh/tonne [43] [44] (~7450 BTU/lb), 14.4-20.3 MJ/kg. [45] [None of these three sets of values come even close to agreeing.] High-efficiency wood pellet stoves and boilers have been developed in recent years, typically offering combustion efficiencies of over 85%. [46]
Wood harvesting and transport operations produce varying degrees of greenhouse gas pollution. Inefficient and incomplete combustion of wood can result in elevated levels of greenhouse gases other than CO 2, which may result in positive emissions where the byproducts have greater Carbon dioxide equivalent values. [17]
The Hughes H-4 Hercules was made mostly of birch wood, despite its better-known moniker, "The Spruce Goose". Birch plywood was specified by the BBC as the only wood that can be used in making the cabinets of the long-lived LS3/5A loudspeaker. [14] Birch is used as firewood because of its high calorific value per unit weight and unit volume. It ...
Smokeless fuels generally have a high calorific value, with that of anthracite being greater than dry wood for example, and many smokeless briquettes are made from this type of coal. Thus anthracite has a calorific value of 32.5 MJ/kg compared with that of dry wood of about 21 MJ/kg.