1. Make the right choice:

When the temperature outside begins to climb:

many people seek the cool comfort of shadowy gardens;

many people seek the cool comfort of outdoor pools;

many people seek the cool comfort of indoor air conditioning.

Air conditioners come:

in various sizes and prices;

in various prices and cooling capacities;

in various sizes, cooling capacities and prices.

Most businesses and office buildings have condensing units:

on their roofs;

on their ground floor;

in their basement.

2. Put the sentences into the right order according to the text continuity:

All condensing units work on the same principles.

Most businesses and office buildings have condensing units on their roofs.

Air conditioners are one of those things that we see every day but seldom pay much attention to.

A window air conditioner unit implements a complete air conditioner in a small space.

3. Mark true (t) and false (f) statements. Correct the false ones:

When the temperature inside begins to clime, many people seek the cool comfort of the garden fresh air.

One type that we see all the time is the window air conditioner.

Most people who live in suburban areas usually have condensing units on their roofs.

IV. Vocabulary knowledge check-up:

1. Match the words to their description:

1) capacity	a) large building for storing goods
2) mall	b) street or covered area with rows of shops, closed to traffic.
3) warehouse	c) cable along which the electric energy is supplied
4) air conditioner	d) tower holding a large tank of water
5) water tower	e) machine which keep a room at the right temperature
6) power line	f) ability to do sty

2. Fill in the missing prepositions where necessary:

Air conditioners come … various sizes, cooling capacities and prices.

Most people who live … suburban area usually have one … them … their backyard.

As you fly … any airport you notice condensing units hidden … the roofs … warehouses and malls.

Air conditions all work … the same principles.

3. Put the words into the right order to make up correct sentences:

Things are, we, conditioners, one, seldom, but, to, much, air, of, see, every, attention, day, pay, those, that.

It, indispensable, work, be, wouldn’t, nice, their, to, magic, how, these, know, machines.

They, principles, though, these, look, all, distinct, even, each, has, these, on, a, the, work, same, pretty, of.

V. Controlled Practice:

Participles. Forms of participles:

Present participle	Past participle
V + ing The exhibition was fascinating. The man testing the machines is our senior engineer.	V + ed (III form of irregular verbs) The businessmen were fascinated by the exhibition. The device tested is defective.

Participle	Active	Passive
Present	Testing	Being tested
Past	____	Tested
Perfect	Having tested	Having been tested

Exercise 1. Choose the correct form of a participle.

I didn’t know you were interested/interesting in mechanics.

Watching the experiment was boring/bored as it failed.

We were surprised/surprising to know they had problems with the new equipment.

The experiment was tiring/tired.

I feel exhausted/exhausting after such a long trip.

It was so much frightened/frightening to hear the noise of the operating machine.

The journey was exciting/excited; we’d love it to last longer.

The laboratory assistant was concerning/concerned that the lab would become a mess after the experiment.

Exercise 2. Put the participles in brackets into the correct form, like in the example.

E.g. The …(fall) leaves make me sad. – The falling leaves make me sad.

… (read) the rule she tried to understand and remember it.

The boy broke his leg … (play) football.

… (sent) to the wrong address the letter didn’t reach him.

We met our friends … (go) home.

… (tell) of his arrival we went to meet him.

He came to some interesting conclusions after … (conduct) this experiment.

… (teach) by a good teacher he knew the English language very well.

Books … (write) by this author sell well.

The question … (ask) provoked a discussion.

We could cope with the task … (read) the instructions.

Exercise 3. Translate the sentences into Ukrainian, paying attention to different forms of participles.

The task facing us is to invent non-toxic materials.

There is a growing interest to technical specialities nowadays.

Having plenty of time we decided to discuss the matter after the class.

Being often interrupted by students the lecturer couldn’t finish the lecture.

Having won the political struggle the leader of the party became very popular.

Having been well prepared for the exam the student could answer all the questions asked.

Yesterday the professor told us about the experiments now being carried out in his laboratory.

She was looking at the illustration shown on the blackboard.

Manuals illustrated with bright examples can be found in the university library.

The data obtained were finally analysed.

VI. Discussion:

1. Answer the following questions:

1. Do air conditioners differ one from another?

2. In what way?

3. What’s the most economical way to cool a small area?

4. Can one window air conditioner cool airports or big office buildings?

5. Does the work of different air conditioners depend on size or look?

6. Do different in size and look conditioners work on the same principles?

2. Add more details to the statement:

We seldom pay much attention to air conditioners.

There are different types of air conditioners.

Air conditioners work on the same principles.

A window air conditioner unit implements a complete air conditioner in a small space.

3. Retell the text.

Unit 7.

How air conditioner

works.

Warm-up:

1. Do you have an air conditioner at home?

2. What do air conditioners serve for?

3. What famous brands of air conditioners do you know?

II. Read and translate the text:

Vocabulary notes:

insulated -	ізольований
evaporation -	випар; паротворення
refrigerant -	спец.холодоагент; охолоджувач
freon -	фріон
genetically -	широко; узагалі
nonflammable -	незаймистий
fluorocarbon -	фторвуглець
propellant -	рушійна сила
dissipate -	розсіювати
expansion valve -	розширювальний клапан; регулюючий вентиль
unit -	агрегат
plug in -	вводити виделку
window frame -	віконна рама
fan -	рискаль гвинта

Text.

An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant, like freon, to provide cooling. The mechanics of the freon evaporation cycle are the same in a refrigerator as in an air conditioner. The term Freon is generically used for any of various nonflammable fluorocarbons used as refrigerants and as propellants for aerosols.

Diagram of a typical air conditioner.

This is how the evaporation cycle in an air conditioner works (Fig.7):

The compressor compresses cool Freon gas, causing it to become hot, high-pressure Freon gas (red in the diagram above).

This hot gas runs through a set of coils so it can dissipate its heat, and it condenses into a liquid.

The Freon liquid runs through an expansion valve, and in the process it evaporates to become cold, low-pressure Freon gas (light blue in the diagram above).

This cold gas runs through a set of coils that allow the gas to absorb heat and cool down the air inside the building.

Fig.7. Diagram of a typical air conditioner

Mixed in with the Freon is a small amount of a lightweight oil. This oil lubricates the compressor.

A window air conditioner unit implements a complete air conditioner in a small space (Fig.8). The units are made small enough to fit into a standard window frame. You close the window down on the unit, plug the unit in and turn it on to get cool air.

Fig.8 Window air conditioner

If you take the cover off of an unplugged window unit, you will find that it contains (Fig.9):

A compressor;

An expansion valve;

A hot coil (on the outside);

A chilled coil (on the inside);

Two fans;

A control unit.

Fig.9. Structure of a Basic Window air Conditioner

The fans blow air over the coils to improve their ability to dissipate heat (to the outside air) and cold (to the room being cooled).

III. Comprehension check-up:

1. Make the right choice:

Air conditioner uses:

the dilution of a refrigerant to provide cooling;

the liquation of a refrigerant to provide cooling;

the evaporation of a refrigerant to provide cooling.

The term Freon is generically used for any of:

various flammable fluorocabons used as refrigerants;

various nonflammable fluorocabons used as refrigerants;

various nonflammable fluorocabons used as carriers.

Mixed in with the Freon is:

a large amount of a lightweight oil;

a small amount of a lightweight oil;

a small amount of a heavyweight oil.

4) The window units are made small enough to fit:

into a specific window frame;

into a large window frame;

into a standard window frame.

2. Put the sentences into the right order according to the text continuity:

1) A lightweight oil lubricates the compressor.

2) The hot gas condenses into a liquid.

3) The mechanics of the Freon evaporation cycle are the same in a refrigerator as in an air conditioner.

4) The cold gas absorbs heat and cools down the air inside the building.

3. Mark true (T) and false (F) statements. Correct the false ones:

1) The compressor compresses cool Freon gas, causing it to become hot, highpressure Freon gas.

2) The hot gas runs through a set of coils so it can absorb its heat.

3)The term Freon is generically used for some nonflammable fluorocarbons used as refrigerants;

4) The lightweight oil lubricates the conditioner.

5) The fans blow air over the coils to improve their ability to dissipate heat and cold.

IV. Vocabulary knowledge check-up:

1. Match the words to their description:

1) refrigerant	a) process by which a liquid changes into a vapour
2) propellant	b) machine that compresses air or other gases
3) compressor	c) cooling cupboard for keeping things cold
4) evaporation	d) substance that refrigerates, eg. liquid carbon dioxide.
5) refrigerator	e) fuel used to propel; propelling agent.

2. Fill in the missing prepositions where necessary:

1. An air conditioner is basically a refrigerator … the insulated box.

2. It uses the evaporation … a refrigerant, … freon, to provide cooling.

3. This hot gas runs … a set of coils so it can dissipate its heat, and it condenses … a liquid.

4. Mixed … … the Freon is a small amount … a lightweight oil.

5) You close the window … … the unit, plug the unit … and turn it … to get cool air.

3. Put the words into the right order to make up correct sentences:

1. Mechanics, evaporation, refrigerator, conditioner, an, in, as, air, the, the, of, cycle, freon, same, of are, the, a.

2. Causing, cool, hot, gas, gas, Freon, highpressure, compressor, the, it, compresses, to, Freon, become.

3. Dissipate, gas, through, this, hot, set, so, a, it, heat, its, can, runs, of, coils.

4. With, in, mixed, is, oil, small, lightweight, amount, Freon, a, a, the, of.

5) Small, standard, units, frame, the, a, to, into, window, are, enough, made, fit.

V. Controlled Practice: