Gas Heating

Gas Heating 

a type of heating in which combustible gases are used as fuel and in which heating units and appliances made for burning gas are installed directly in the spaces to be heated. A gas heating system also consists of gas pipes (which supply the gas to the heating units), shutoff-regulating fittings, and automatic devices to ensure safe use of the gas.

Various types of gas heating units exist. Infrared gas radiators are often used for large-volume areas; the burners of these units, which are usually located below the ceiling, are exposed to the room area. An infrared gas radiator is actually a housing in the form of a reflector turned toward the floor; located in the lower part is an end piece made of flat ceramic plates having a large number of tiny holes (1.5 mm in diameter). The fuel mixture (gas and air) is supplied to the space between the housing and the end piece (nozzle), from where it flows out in a steady stream through the holes and is ignited by a spark plug. The ceramic plates are warmed up to temperatures of 700°-900° C, whereupon further combustion of the gas occurs on the red-hot surface of the end piece, which is also the element that radiates the flow of heat to the heating zone of the space. More complete burning of the gas takes place during the surface (flameless) combustion, as shown by the almost complete absence of carbon monoxide from the combustion products. The combustion products are removed from the room space together with the air exhausted by the ventilating system.

With respect to health, the best units are gas heaters that discharge the combustion products to the atmosphere (for example, through chimneys) and units with the gas flue and combustion chamber insulated from the space and with the air needed for combustion supplied from the outside. These units are generally installed at outside walls below windows. They consist of a heater casing with a combustion chamber in which the gas is burned; the casing is covered by a protective housing with openings for passage of the heated air to the room space. The heater casing is connected with the outside air by two ducts passing through a wall; outside air is supplied to the combustion chamber through one duct, and the combustion products that have passed through the heater casing and lost heat are discharged to the outside through the other duct.

In the USSR gas heating is used chiefly in several types of industrial buildings, as well as in public buildings with temporary human occupancy. In addition, gas is widely used as a heating fuel in the boilers (and occasioally in the air preheaters) of water, steam, and air heating systems. The extensive use of gas for heating in industrial and municipal-utility enterprises and in central heating-supply boiler rooms, especially those in large cities, is advantageous largely because the products of gas combustion contribute almost no pollution to the city air environment and because the gas itself is delivered to consumers through pipelines, without putting a burden on the transportation system. The adoption of automatic and remote gas combustion controls contributes to the safe use of gas. Boiler rooms that operate on gas fuel may be situated on an upper floor of the building to be heated. Gas may also be used in combined systems, which provide buildings with heating during the winter and cooling during the summer.

REFERENCE

Otoplenie i ventiliatsiia, 3rd ed., part 1. Moscow, 1964.

I. F. LIVCHAK