Lesson 2 How Does Air Conditioning Work? Part 1
Introduction
Air conditioners employ the same operating principles and basic components as your home refrigerator. But instead of cooling just the small, insulated space inside of a refrigerator, an air conditioner cools a room or a whole house. Refrigerators use energy (usually electricity) to transfer heat from the cool interior of the refrigerator to the relatively warm surroundings of your home; likewise, an air conditioner uses energy to transfer heat from the interior of your home to the relatively warm outside environment.
Most air conditioning systems have five mechanical components:
• a compressor • a condenser • an evaporator • a blower of a fan • a chemical refrigerant
Most central air conditioning units operate by means of a split system That is, they consist of a ‘hot’ side, or the condensing unit—including the condenser, the compressor and the fan—which is situated outside your home, and a ‘cold’ side that is located inside your home where the evaporator is mounted, sometimes as part of a furnace. Air conditioners use chemicals (or chemical refrigerants) that easily convert from gas to liquid and back again. Through the piping the refrigerant flows from one unit to another. It is the refrigerant that absorbs the energy in one unit and releases it in the other.
Principles of Refrigeration
- Liquids absorb heat when changed from liquid to gas
- Gases give off heat when changed from gas to liquid.
For an air conditioning system to operate with economy, the refrigerant must be used repeatedly. For this reason, all air conditioners use the same cycle of compression, condensation, expansion, and evaporation in a closed circuit. The same refrigerant is used to move the heat from one area, to cool this area, and to expel this heat in another area.
- The refrigerant comes into the compressor as a low-pressure gas, it is compressed and then moves out of the compressor as a high-pressure gas.
- The gas then flows to the condenser. Here the gas condenses to liquid, and gives off its heat to the outside air.
- The liquid then moves to the expansion valve under high pressure. This valve restricts the flow of the fluid, and lowers its pressure as it leaves the expansion valve.
- The low-pressure liquid then moves to the evaporator, where heat from the inside air is absorbed and changes it from a liquid to a gas.
- As a hot low-pressure gas, the refrigerant moves to the compressor where the entire cycle is repeated.
Note that the four-part cycle is divided at the center into a high side and a low side This refers to the pressures of the refrigerant in each side of the system
Vocabulary
insulated – изолированный
convert from….to - преобразовываться из…в
condenser [kən’densə]– конденсатор
evaporator [i’væpəreitə]- испарительный теплообменник
refrigerant – хладагент
furnace [fз:nis]– обогреватель
ext'ract – получать, извлекать
blower/ Fan – вентилятор
expansion – снижение давления
expel – выпускать
expansion valve - терморегулирующий вентиль для жидкого хладагента
piping - транспортировка по трубопроводу/гидропроводу, сеть трубопроводов, подача по трубам
Exercise 1
Find Russian equivalents to the following words in the text. Learn them by heart.
Кондиционер, холодильник, вместо (чего-то), охлаждать, замкнутый, компрессор, конденсатор, испарительный теплообменник, вентилятор (2 варианта), хладагент, химический, посредством/ с помощью, обогреватель, химический реагент, преобразовываться из…в, подача по трубам, течь, поглощать, освобождать/испускать (3 варианта), блок/часть/секция, повторно, сжатие, испарение, цикл/кругооборот, клапан/вентиль
Exercise 2
Match the synonyms. There can be more than two synonyms.
Absorb, part, blower, valve, cycle, with the help of, compression, shutter, again and again, heater, fridge, give off, chill, multiply, closed, fan, soak up, using, expel, swallow, refrigerator, cool, insulated, by means of, furnace, release, unit, repeatedly, pressing, circuit, flap
Exercise 3
Match the words to their definitions.
1) insulated 2) fan 3) valve 4) absorb 5) condenser 6) refrigerator 7) convert 8) release
|
a) a device that cools gas in order to change it into a liquid b) to change or make something change from one form, purpose, system, etc. to another c) to take in a liquid, gas or other substance from the surface or space around d) a device for controlling the flow of a liquid or gas, letting it move in one direction only e) to let somebody/something come out of a place where they have been kept or trapped f) protected with a material that prevents heat, sound, electricity, etc. from passing through g) a piece of electrical equipment in which food is kept cold so that it stays fresh h) a machine with blades that go round to create a current of air |
Exercise 4
Fill in the sentences with the words from the box
Evaporation, valves, flows, release, converted, air conditioning, absorb (2), absorbed, valve (2) |
1) Plants ________carbon dioxide from the air.
2) Snow cover prevents ________of water from the soil.
3) The cream is easily ________into the skin.
4) A _________shuts off the flow from the boiler when the water is hot enough.
5) The hotel is going to be __________into a nursing home.
6) From here the river __________north.
7) Firefighters took two hours to _________the driver from the wreckage (обломки).
8) Growing up in warm summer weather in NY meant sunshine, humidity and_________.
9) The plumber will fit some new safety_________.
10) You need special tools to open the _________.
11) Buildings can be designed to _________and retain heat.