Search results
Results from the WOW.Com Content Network
Older furnaces sometimes relied on gravity instead of a blower to circulate air. [1]Gas-fired forced-air furnaces have a burner in the furnace fueled by natural gas.A blower forces cold air through a heat exchanger and then through duct-work that distributes the hot air through the building. [2]
Requires less energy than electric resistance heating and possibly more efficient than fossil fuel fired furnaces (gas/oil/coal). Air source types may not be suitable for cold climates unless used with backup (secondary) source of heat. Newer models may still provide heat when coping with temperatures below 0 °C (32 °F).
Superheater operation is similar to that of the coils on an air conditioning unit, although for a different purpose. The steam piping is directed through the flue gas path in the boiler furnace, an area in which the temperature is typically between 1,300 and 1,600 degrees Celsius (2,372 and 2,912 degrees Fahrenheit).
In a water boiler, draft is the difference between atmospheric pressure and the pressure existing in the furnace or flue gas passage. [1] Draft can also be referred to as the difference in pressure in the combustion chamber area which results in the motion of the flue gases and the air flow.
The annual fuel utilization efficiency (AFUE; pronounced 'A'-'Few' or 'A'-'F'-'U'-'E') is a thermal efficiency measure of space-heating furnaces and boilers.The AFUE differs from the true 'thermal efficiency' in that it is not a steady-state, peak measure of conversion efficiency, but instead attempts to represent the actual, season-long, average efficiency of that piece of equipment ...
Diagram of natural draft gas furnace, early 20th century. The first category of furnaces is natural draft, atmospheric burner furnaces. These furnaces consisted of cast-iron or riveted-steel heat exchangers built within an outer shell of brick, masonry, or steel. The heat exchangers were vented through brick or masonry chimneys.
The process starts by charging solid sinter and heated coke into the top of the blast furnace. Preheated air at 190 to 1,050 °C (370 to 1,920 °F) is blown into the bottom of the furnace. Zinc vapour and sulfides leave through the top and enter the condenser. Slag and lead collect at the bottom of the furnace and are tapped off regularly.
This degrades the efficiency of the reactor, so reaction conditions are designed to minimize this. Nonetheless, a steam cracking furnace can usually only run for a few months at a time between de-cokings. Decokes require the furnace to be isolated from the process and then a flow of steam or a steam/air mixture is passed through the furnace coils.