SANITARY ENGINEERING IN THE MODERN TOWN

Tasks before reading:

1. Choose suitable Russian words to English terms. Explain their meaning

Panel Heating

(1) Heating and ventilation are two branches of engineering which are very closely connected, they are therefore treated as a dual subject. Both are concerned with providing a required atmospheric environment within a space, the former with respect to heat supply to produce a desired temperature for maintaining comfort, health or efficiency of the occupants, the latter with regard to supply and removal of air frequently with emphasis on contamination of the air. Air-conditioning is closely related to both heating and ventilation arid will therefore be dealt with later.

(2)It is for heating to prevent the too rapid loss of heat from the body. By heating the ambient air of walls, ceiling or floor the rate of heat loss from the body is controlled. Some old concepts of heating were gradually changed since engineers obtained more precise knowledge about how the body loses heat. Insufficient attention was paid formerly to loss by radiation, which is the transmission of energy in the form of waves from a body to surrounding bodies at a temperature. The human being also loses heat by conduction (through his clothes) and convection, the latter by air currents not only past his skin or outside clothing surface but also by evaporation of moisture from his skin (respiration). The determining of the capacity or size of the various components of the heating system is based on the fundamental concept that heat supplied to a space equals heat lost from the space. The most widely used system of heating is the central heating, where the fuel is burned in one place—the basement or a specially designed room and from which steam, hot water or warm air is distributed to adjacent and remote spaces to be heated.

(3)There are two most common systems of heating—hot water and steam. Both systems are widely used nowadays. A hot-water system consists of the boilers and a system of pipes connected to radiators suitably located in rooms to be heated. The pipes, usually of steel or copper, feed hot water to radiators or convectors which give up their heat to the room. The water, now cooled, is returned to the boiler for reheating.

(4)As for steam systems, steam is generated usually, at less than 5 pounds per square inch in the boiler and the steam is led to the radiators through or by means of steel or copper pipes. The steam gives up its heat to the radiators and the radiator to the room and the cooling of the steam condenses it to water. The condensate is returned to the boiler either by gravity or by a pump. The air valve on each radiator is necessary for air to escape. Otherwise it would prevent steam from entering the radiator.

(5) Recent efforts to completely conceal heating equipment have resulted in an arrangement whereby the fluid, whether it be hot water, steam, air, or electricity, is circulated through distribution units embedded in the building construction. Panel heating is a method of introducing heat to rooms in which the emitting surfaces are usually completely concealed in the floor, walls, or ceiling. The heat is disseminated from such panels partly by radiation and partly by convection, the relative amounts depending on the panel location. Ceiling panels release the largest proportion of heat by radiation and floor panels the smallest. The proportion of heat disseminated by radiation and convection is also dependent to some extent upon panel-surface temperatures. The basic advantage claimed for a panel healing system is that of comfort.

(6)Application of certain panels is frequently restricted by structural details. Other factors to be considered are type of occupancy, furniture or equipment location, large glass areas, heat-storing capacity of building construction, room height, possible change of wall partitions, climate, exposure, and first cost.

As for fuels used for heating buildings they include coal, oil, manufactured and natural gases and wood. There are two other sources: electricity and steam. Nowadays gas fuel is being used on an ever increasing level.

Tasks after reading:

4. Find correct Russian translation of English words. Compose sentences with them on the topic of the text. Find unnecessary words