HEATING

From Big Medical Encyclopedia

HEATING — heating of air of the enclosed space in cold season for maintenance of temperature at the set level.

Air temperature is one of major factors in a complex of the weather conditions defining heat exchange and thermal balance of an organism and external environment.

Despite rather wide biological adaptability of the person, his ability to an equilibration with Wednesday it is limited to rather small range of fluctuations of weather conditions. At muscular rest of people sensitively reacts even to rather insignificant fluctuations of the meteorological factors causing certain physiological shifts in an organism, to-rye can adversely affect the general condition, health and efficiency of the person.

Though these physiological shifts also are in character compensatory and zashchitnoprisposobitelny reactions of an organism, nevertheless it is impossible to consider that long and maximum use of these reactions is indifferent for an organism and can provide optimal conditions of its life activity. Discomfortable conditions microclimate (see) in some cases can lead not only to deterioration in health and decrease in efficiency of the person, but also to cause in it a number of the pathological phenomena as a result of cooling or overheating.

Therefore ensuring thermal comfort in inhabited and public places at which the central nervous system receives the smallest quantity of thermal exteroceptive irritations is an important hygienic task.

From here the following follows main hygienic requirements, shown to O. of residential and public buildings: a) providing in rooms during the cold period of year at any outside temperatures of comfortable level t ° within 17 — 22 ° (in dependence og climatic conditions); b) stability of air temperature in rooms with its minimum fluctuations within a day (no more than ±2 °); c) hypodispersion of air temperature in rooms (fluctuations in the horizontal direction no more than ±1 °, temperature increase in the vertical direction on each meter of height of the room no more than 1,5 °); d) an exception of the adverse factors influencing composition of air of the room: burning of dust on the surface of heating devices (a cut sharply increases at temperatures over 85 °); release of carbon monoxide, combustion products of fuel and others harmful and badly the smelling gases; mechanical pollution of the room fuel, ashes etc.; e) availability to leaving and ease of cleaning of basic elements of system (M. S. Goromosov, N. A. Tsiper, 1961).

The lake is carried out by the system including basic elements: the generator of heat, heat conductors, on the Crimea moves the heat carrier, and heating devices.

On a way of a thermolysis distinguish convective and radiation heating devices, the same treats also systems O. However in pure form these systems practically do not meet since in each of them both ways of a heat transfer, as a rule, take place. At convection system of heating of 70 — 80% of heat the rest is transferred by convection, radiation, at radiant system of heating — on the contrary.

The main heating device of convective type is the radiator applied at the water and steam Lake.

At radiation O. use heating devices in the form of panels with a big plane heating surface, wall radiators various designs with small convection intervals between elements (fig.) or suspended panels with high temperature of radiating surfaces.

The system O., at a cut heat is produced in the same place where it is used, i.e. in the heated room, is called local. In local O.'s systems (wood, coal, electric, gas) the generator of heat combines with heat conductors and heating devices in one unit (furnace).

Local O.'s systems possess a number of shortcomings, such as irregularity of air temperature in rooms within a day; existence in the heated room of negative radiation, hl. obr. from outside walls and windows; rather high temperature on certain sites of a surface of heating devices that causes burning of dust and deterioration in composition of air; difficulty of regulation of a thermolysis of heating surfaces; pollution of rooms during the use of wood furnaces fuel, ashes, slag, smoke and so forth; danger of release of harmful gases. Besides, the majority of heating devices of local O. demand continuous operation in connection with their small heat capacity.

Defects of local heating are eliminated by room O., at Krom of the room of the apartment are provided with heat from one generator serviced by residents and placed out of premises.

The systems O. working from the central generator remote from the heated rooms are called central.

These systems O. (water, steam, steam-and-water, air, water radiant, etc.) have essential advantages: provide more uniform thermal conditions in rooms, exclude pollution of the intra housing environment combustion products and fuel, are more reliable and convenient in management.

However in steam systems of central heating where the heat carrier is water vapor of low pressure, the surfaces of heating devices have high temperature (more than 100 °) and attemperation is complicated.

Along with water and steam heating air O. where as the heat carrier the fresh air heated in heaters and moistened is used is applied. This system O. is often combined with the air conditioning system (see. Air conditioning ).

Gigabyte. most of all the system O. meets the requirements, in a cut the radiation of heat since at the same time in rooms negative radiation from outside barriers decreases that provides comfortable conditions at lower air temperature prevails.

Heating devices at radiant O. have rather low surface temperature (25 — 50 °) that the thermal discomfort connected with temperature increase of surrounding barriers warns body temperatures are higher.

To a design of heating devices are shown a dignity. - a gigabyte., architectural and esthetic requirements. Outward of devices shall be in harmony with interiors of rooms, is necessary about-zrevayemost all device and space behind it, the design and finishing of the heating device shall not complicate its cleaning and disinfecting. Requirements to the devices installed in to lay down are especially big. - professional, institutions, residential and public buildings, preschool institutions, schools.

Precautionary and current dignity. supervision of construction and operation of systems O. in buildings and rooms various to destination is regulated Construction Norms and Regulations and a gigabyte. rules.

Reception of systems O. is carried out to operation on the basis of consideration of the project documentation and trial start-up, to-ry is carried out for the purpose of leakage test of all connections, assessment of thermal efficiency to winter time, or a progrevayemost of devices in summertime. At assessment of thermal efficiency define distribution of air temperature in placements on verticals and a horizontal and temperature on the surfaces of heating devices; at air O.'s assessment mobility of air in rooms and noise level from heat installations is defined.



Bibliography: Theological V. N., V. P.'s Goldfinches and Reasons of H. H. Heating and ventilation, M., 1980; At-ber a certain Yu. D. Predictive questions of ensuring thermal comfort in residential and public buildings, in book: Vopr. gigabyte. dwellings and medical profilakt. institutions, under the editorship of H. M. Danzig, page 19, M., 1971; Provincial Yu. D. and Cora Nevsky E. I. Hygienic bases of conditioning of a microclimate of residential and public buildings, M., 1978; Kazantsev I. A. Use of the electric power for heating of residential buildings, M., 1976; JI and in the h and to I. F. Room heating, M., 1977; With t e-panyan V. M. Heating, p.1. Heating devices of systems of central heating, Ashgabat, 1980; Shch EC and I. R N. Air heating units, M., 1977.


S. N. Kimina.

Яндекс.Метрика