Heating

Heating and ventilation are two branches of engineering which are very closely connected and concerned with providing a required atmospheric environment within a definite space. Air-conditioning is closely related to heating as well as ventilation.

The most widely used system of heating is the central heating, where the fuel is burned in one particular place – the basement or a specially designed room for the purpose from which steam, hot water or warm air is transmitted to all the necessary places to be heated.

The hot water system and the steam system are at present the two most common system of heating. A hot water system consists of a boiler and a whole system of pipes connected to all the radiators suitably located in the building.

The pipes are usually made of steel. But they can be made of copper and plastics too. In fact, copper pipes serve the purpose very well. The pipes feed hot water to radiators or convectors. The cooled water is returned to the boiler where it is reheated.

As for steam systems steam is generated in the boiler and then it is conveyed to the radiators through pipes. The steam gives up its heat to the radiators and the radiators 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.

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. 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.

The advantages of central heating are:

1. fuel and ashes are kept outside the occupied spaces;

2. individual fuels are not required;

3. cleanliness;

4. equable temperature maintained in all parts, easily controlled automatically.

Ex. 2 Answer the questions.

1. What branches of engineering which are connected with a required atmospheric environment can you mention?

2. What is air conditioning connected to?

3. What is the most widely used system of heating?

4. What does a water system consist of?

5. What are pipes made of?

6. How do pipes work? How do steam systems work?

7. How is the condensate returned the boiler?

8. What is necessary for the air to escape?

9. How is that introduced to rooms?

10. What is used being for heating buildings?

11. How is gas fuel used nowadays?

TEXT 7

Ex.1 Read the text and translate it into Russian.

ALL-YEAR AIR CONDITIONING, VENTILATION, GAS SUPPLY

Air conditioning implies the control of temperature, humidity, purity and motion of the air in an enclosure. In our modern world of science and highly developed technology air conditioning is of great significance for industrial processes as well as for human comfort.

Air conditioning for human comfort is employed in both large and small installations, such as theatres, office buildings, department stores, residences, airplanes, railways, cars and submarines.

All-year air-conditioning systems must provide means for performing all the processes required for winter and sum­mer air conditioning. The basic pieces of equipment are the filters, preheat coils, humidifiers, dehumidifiers, reheat coils, additional cooling coils, fans and controls. The control of air purity can be achieved in various degrees. As a minimum control some sort of filtering must be done near the entrance of the air-conditioning system. Possibly the most efficient filtering device is the electrostatic precipitator.

In order to establish the size and operational require­ments of an air-conditioning system, the maximum probable heating and co-demands have to be calculated. The maximum probable heating demand is usually for winter air conditioning and it involves heating and humidifying. The maximum probable cooling demand is generally for summer applica­tions and requires cooling and dehumidifying.

As far as ventilation is concerned the modern theory to this effect can be summed up in the statement that for places of general assembly the purpose of ventilation is to carry away excess heat and odours and that normally 10 cu. ft per minute of outside air per person is sufficient to accomplish this objective. In buildings such as homes, the leakage of air through cracks in doors and windows is usually sufficient to meet this requirement. Although ventilation was formerly con­cerned with the supply of fresh air to and the removal of hot and contaminated air from the space it gradually came to be associated with cleaning of air.

Industrial buildings often present special problems in ventilation. There are certain industrial processes that are accompanied by the production of air-born dust, fumes, toxic vapours and gases which are hazardous to the health of workers.

Another indispensable part of modern amenities is gas supply. It has come now to be of a very wide use. With an intensive exploration of finding natural gas it has gradually replaced the manufacture in its utilization. At the present time natural gas is put to large-scale economic use. The prin­cipal utilization of natural gas is as a clean, convenient, eco­nomical source of heat. In homes it is used for cooking, water heating, refrigeration for food as well as for space heating.

Ex.2 Answer the questions.

1. What is air-conditioning?

2. What purposes is air conditioning used for?

3. Where is air conditioning used?

4. What do you know about ventilation of buildings?

5. Does ventilation receive proper attention in house buildings?

6. How many air changes per hour should be in the building?

7. Why is one air change an hour not sufficient?

TEXT 8

Ex.1 Read the text and translate it into Russian.