Heaters
A heater is any object that emits heat or causes another body to reach a higher temperature. In a household or domestic setting, heaters are most commonly appliances whose purpose is to produce heating (i.e. warmth). Heaters exists for all states of matter, including solids, liquids and gases.
The opposite of a heater(for warmth)is an air cooler(for cold)(see air conditioning)used to keep the user cooler than the temperature originally near by them. A central heating system provides warmth to the whole interior of a building (or bit of a building) from one point to several rooms. When added to other systems for the purpose of control the building climate, the whole system can be a HVAC (heating, ventilation and air conditioning) system.
Central heating differs from local heating in that the heat generation occurs in one place,such as a furnace room in a house or a mechanical room in a huge building(though not necessarily at the"central"geometric point).The most usual method of heat generation involves the combustion of fossil fuel in a furnace or boiler.The end resultant heat then gets distributed: generally by forced-air through ductwork, by water circulating through pipes, or by steam fed through pipes. Increasingly, buildings utilize solar-powered heat sources, in which case the distribution system usually uses water circulation.
In much of north Europe and in urban bits of Russia, where people seldom require air conditioning in homes because of the temperate climate,most new housing comes with central heating installed. Such areas usually use gas heaters, district heating, or oil-fired systems. In the western and southern United States natural-gas-fired central forced-air systems occur most generally; these systems and central-boiler systems both occur in the far north regions of the USA. Steam-heating systems, fired by coal, oil or gas, feature in the USA,Russia and Europe: first and foremost for huger buildings.
Electrical heating systems occur less generally and are only practical with low cost electricity or when geothermal heat pumps are used. Considering the combined system of central generating plant and electric resistance heating, the overall efficiency will be fewer than for direct use of fossil fuel for space heating.
Electric heating or resistance heating converts electricity directly to heat. Electric heat is usually more expensive than heat produced by combustion appliances like natural gas, propane, and oil. Electric resistance heat can be provided by baseboard heaters, space heaters, radiant heaters, furnaces, wall heaters, or thermal storage systems.
Electric heaters are most commonly part of a fan coil which is part of a central air conditioner.They circulate heat by blowing air across the heating component which is supplied to the furnace through return air ducts.Blowers in electric furnaces move air over one to five resistance coils or components which are most commonly rated at five kilowatts. The heating components activate one at a time to avoid overloading the electrical system.Overheating is prevented by a safety switch called a limit controller or limit switch. This limit controller may shut the furnace off if the blower fails or if something is blocking the air flow. The heated air is then sent back through the home through stock ducts.