Hot-Air Heating

Hot-Air Heating


a system for heating premises by means of hot air. A hot-air heating system includes air pre-heaters, in which air may be heated by hot water, by steam (in air heaters), by heat given off by the burning of various types of fuel (in flame air preheaters), or by electricity (in electric air preheaters); air ducts, which deliver the air to the premises to be heated; air-supply and air-intake grilles, through which the air is fed to the area to be heated and collected for supply to the air preheater; and shutoff and regulating dampers in the air ducts. Air ducts, grilles, and dampers are not necessary if the air preheater is located directly in the area to be heated.

There are various types of hot-air heating systems, including recirculating (return) air heating, in which all of the air supplied to the air preheater is taken from the area being heated; and combined hot-air heating and ventilation, in which the air supply comes partially from the area being heated and partially from outside air. (The ratio between the recirculating and outside air volumes is adjustable over a wide range.) Combined hot-air heating and ventilation systems that operate only on outside air (without recirculation and return ducts) are sometimes called direct-flow systems. Such systems are used, for example, in residential buildings, where one air preheater serves several apartments. (In this case, a recirculating system would result in the undesirable entry of air from one apartment to another.) Nonrecirculating hot-air heating systems are also installed in industrial premises containing production processes that are accompanied by the emission of noxious gases or dust. The transfer of air in hot-air heating systems (in both recirculating and heating-ventilation systems) may be natural (owing to air temperature and density differences before and after the air preheater) or mechanical. An electric fan is installed for mechanical air transfer.

The chief advantage of a hot-air heating system over other types of central heating is the smaller amount of metal used owing to the fact that hot-air heating systems do not require the installation of heating equipment and piping such as that used, for example, in hot-water and steam heating systems. At the same time, the combined hot-air heating and ventilation system solves the problem of air exchange in an area and sometimes, in the case of preconditioning of the air supplied to an area (humidification, cooling, drying, and so on), the problem of air conditioning as well. In industrial and commercial workshops, the halls of public buildings, and buildings with a large number of rooms (in which the building structure makes it possible to use existing spaces as passages), a hot-air heating installation can be considerably simpler than other types of central heating. In the USSR hot-air heating, which is widely used in industrial workshops, is usually accomplished by means of units installed in the areas to be heated. Heating capacities for industrial hot-air heating units range from 5.8-11.6 watts to 5.8 megawatts (5-10 to 500,000 kilocalories per hour).

Combined hot-air heating and ventilation systems (without recirculation) have also begun to be used in schools and residential dwellings with four, five, or more stories. Hot-air heating is used for single-apartment residential dwellings in the USA and several other countries.


Otoplenie i ventiliatsiia, 2nd ed., part 1. Moscow, 1965.


hot-air heating

A system of heating by which air, warmed above a fire chamber, is distributed through ducts.
References in periodicals archive ?
A sequential IR and hot-air heating method can produce roasted almonds with up to 60% time reduction and improved Salmonella reduction compared to regular hot-air roasting.
Although the overall quality of the almonds produced with SIRHA and hot-air heating was similar during their first three months of storage, their peroxide value and the concentration of aliphatic aldehydes differed significantly and increased significantly during storage.
Batching plant specifications for Dundas included: four bulk powders, for a total of 800 tons of storage; five aggregates, totaling 800 tons of storage; hot-air heating of all aggregates; instantaneous hot-water heating with quick recovery storage tank; holding hopper above the twin-shaft mixer for pre-weighing of batch; automated carrousel to fill one gantry crane bucket while positioning the other bucket for take away by the gantry; full automation for the production of SCC to 150 yd.
Before the dry skin started, I had just moved in to a house with a gas oven and gas hot-air heating system.
It has also improved the efficiency of its hot-air heating system to make it more adaptable to moulds of various sizes and shapes.
The scientists compared the effectiveness of three approaches: conventional hot-air heating, infrared heating, or infrared heating followed by hot-air heating--a pairing that they dubbed "SIRHA" (sequential infrared and hot air).
Temperature and air flow studies conducted by the engineers revealed two immediate problems: continual drafts of warm, moist air being forced up to the chapel ceiling by the thousands of visitors passing through each day, and strong drafts from a hot-air heating system, installed under the chapel's floor, that blew dirt and damaging particulates continually up toward the ceiling.
Currently, manufacturers have commercialized Micro-CHP systems in both Europe and Japan, however these products are typically not designed for use in homes with forced hot-air heating, the dominant heating system in the U.
According to a recent Gallup study, more than 59 percent of American households use some form of forced hot-air heating, a method which causes the air inside the home to become dry.
The porous quality facilitates rapid hot-air heating of the sheet to forming temperature.
Any historian will tell you that the ancient Romans devised a system of hot-air heating, and in here we find the very earliest examples of hand-driers, all of them out of order.