Read the sentences and say whether they are true of false. Correct the false sentences.

1) A security alarm system is designed to detect only intrusion.

2) Security alarms are used for protection against burglary or property damage.

3) Prisons also use security systems for control of guards.

4) The most basic alarm consists of one or more sensors to detect intruders, and an alerting device to indicate the intrusion.

5) Premises control unit reads sensor inputs, tracks arm/disarm status, and signals intrusions.

6) Computer circuit boards and a power supply are located inside a metal enclosure.

7) Sensors include bells, sirens, and/or flashing lights.

8) Alerting devices serve the dual purposes of warning burglars

of intrusion, and potentially scaring off occupants.

9) Keypads typically feature either indicator lights, or small multi-character display.

10) Security devices are used to detect thieves and feature spotlights, cameras & lasers.

 

Exercise 4

Solve the crossword

 

Across

1) a small part of a machine that you press to make it work

2) a connection between two or more people or things

3) happening or done without involving other people, actions, etc. in between

4) to discover or notice something, especially something that is not easy to see, hear, etc

5) he opportunity or right to use something or to see somebody/something

6) the system of wires that is used for supplying electricity to a building or machine

7) telling or showing somebody that something bad or unpleasant may happen in the future so that they can try to avoid it

Down

1) using radio, microwaves, etc. (as opposed to wires or cables) to transmit signals

2) insurance against fire, injury, damage, etc.

3) to tell somebody about something, especially something dangerous or unpleasant that is likely to happen, so that they can avoid it

4) made of many different things or parts that are connected; difficult to understand

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 [kə n’densə ]– конденсатор

evaporator [i’væ pə reitə ]- 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

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1. B. Transform the following sentences from active into passive voice.
2. Ex. 6. Give your reasons as to why the rules of the Sequence of Tenses are not observed in the following sentences.
3. Ex.11 Complete the sentences
4. Ex.3. Translate the sentences from Russian into English.
5. EXERCISE 2 Fill in the gaps in the sentences with the correct prepositions and translate them.
6. EXERCISE 2 Translate the following sentences from Russian into English in writing.
7. EXERCISE 20 Are the following statements true or false? Correct the false ones with the right information and discuss your answers with a partner. Use the texts 1, 2 if necessary.
8. EXERCISE 4 Complete the sentences.
9. EXERCISE 6 Translate the following sentences into Russian.
10. EXERCISE 7 Are the following statements true (T) or false (F)? Correct the false ones with the right information and discuss your answers with a partner.
11. EXERCISE 9 Decide whether the statements are true or false. Correct them if necessary.
12. EXERCISE 9 Translate the sentences from Russian into English.