Giáo trình Mô đun Tiếng Anh chuyên ngành - Kỹ thuật máy lạnh và điều hòa không khí

routine cleaning. 
Central air conditioners should be professionally inspected and adjusted before 
the beginning of every cooling season. 
Caution: 
Before doing any work on an air conditioning system, make sure the 
power to the system, both to the condenser and to the evaporator assembly, is 
turned off. 
 45 
UNIT 6: HEAT PUMPS AND HEAT RECOVERY 
Mã bài: MĐ23 - 06 
PART 1: READING COMPREHENSION: 
1.1. Reading text: Air - conditioning: 
Where heat transfer is taking place at the saturation temperature of a fl uid, 
evaporation or condensation (mass transfer) will occur at the interface, 
depending on the direction of heat flow. In such cases, the convective heat 
transfer of the fluid is accompanied by conduction at the surface to or from a thin 
layer in the liquid state. Since the latent heat and density of fl uids are much 
greater than the sensible heat and density of the vapour, the rates of heat transfer 
are considerably higher. The process can be improved by shaping the heat 
exchanger face (where this is a solid) to improve the drainage of condensate or 
the escape of bubbles of vapour. The total heat transfer will be the sum of the 
two components. Rates of two - phase heat transfer depend on properties of the 
volatile fluid, dimensions of the interface, velocities of fl ow and the extent to 
which the transfer interface is blanketed by fl uid. The driving force for 
evaporation or condensation is the difference of vapour pressures at the 
saturation and interface temperatures. Equations for specific fluids are based on 
the interpretation of experimental data, as with convective heat transfer. Mass 
transfer may take place from a mixture of gases, such as the condensation of 
water from moist air. In this instance, the water vapour has to diffuse through the 
air, and the rate of mass transfer will depend also on the concentration of vapour 
in the air. In the air – water vapour mixture, the rate of mass transfer is roughly 
proportional to the rate of heat transfer at the interface and this simplifi es 
predictions of the performance of air - conditioning coils. 
PART 2: LANGUAGE WORK: 
* Task 1: Cause and effect expression: 
Study this sentence: 
Insulation breakdown leads to short circuits: 
This sentence contains a cause and an effect. We can link a cause and an 
effect as follow: 
 46 
We can also put the effect first: 
When a cause has several effects or when an effect has a number of 
possible causes, we put CAN or MAY before the causative expression. 
Example: 
Sparking MAY be caused by worn brushes. 
Sparking CAN be caused by a worn commutator. 
Similarly, instead of THE cause/ effect/ result/ consequence of, we write 
ONE cause/ effect/ result/ consequence of. 
Example: 
 Worn brushes are ONE cause of sparking. 
 A worn commutator is ONE cause of sparking. 
 Effect 
Short 
circuits 
 Cause 
Insulation 
breakdown 
Are caused by 
result from 
arise from 
are the effect of 
are the result of 
are the consequence of 
are due to 
 Cause 
Insulation 
breakdown 
 Effect 
short 
circuits 
causes 
results in 
produces 
leads to 
gives rise to 
is the cause of 
 47 
Now match these cause and the effect pairs. Then link them using 
expressions given above. Write 2 sentences for each example, 1 with cause first 
and the other with effect first. 
Cause Effect 
1 . glare arcing across the points 
2 . eddy currents power losses in transformers 
3 . excessive heat serious accidents 
4 . faulty soldering breakdown of the motor 
5 . speaking discomfort to the eyes 
6 . failure of a point capacitor damage to semiconductors 
7 . exceeding the motor rating bad joints 
8 . faulty earth connections interference in receivers 
* Task 2: Rewrite the following description, using cause and effect expression. 
(Homework): 
* Task 3: Describing sequence: Time clause 
Study this list of events in the manufacture of carbon resistors. 
overrunning 
a motor 
excessive heat 
insulation 
breakdown 
short circuits 
blown fuses 
1 2 3 
4 
 48 
We can show that event 2 follow event 
We can show that event 2 follow event 1 by using sequence word FIRST, 
THEN. 
Example: 
FIRST the resistive element is inserted into the ceramic housing. THEN 
the ends are sprayed with metal. 
We can also show the sequence using the time clauses. 
Example: 
AFTER THE RRESISTIVE ELEMEMT IS INSERTED IN A CERAMIC 
HOUSING, the ends are sprayed with metal. 
BEFORE THE END OF THE ELEMENT ARE SPRAYED WITH 
METAL, it is inserted into the ceramic housing. 
The part of each sentence in capitals is a time clause. 
Time clause can also put last in the sentence. When this happens, there is 
no comma between the time clause and the rest of the sentence. 
Example: 
The ends of the element are sprayed with metal after it is inserted into the 
ceramic housing. 
Now write sentences linking these events with time clause using the time 
word given. 
4. The ends of the resistor are sealed. 
2. The ends of the element are spayed with 
metal. 1. The resistive is element is inserted 
into the ceramic housing. 
Ceramic 
element 
3. End caps and leads are forced on to the 
sprayed ends. 
4. The ends of the resistor are sealed. 
 49 
* Task 4: Put these events in sequence with the help of the diagram. 
(Homework): 
(a) the signal is again amplified 
(b) the desired signal is fed to the acceptor circuit 
(c) the signal is amplified 
(d) the signal is fed to a loudspeaker 
(e) the signal is mixed with a signal from the oscillator to give a standard 
intermediate frequency 
(f) the signal is rectified by the detector. 
* Task 5: Describing sequence: Reduced time clauses: 
We can show that event 2 follows event 1 using a time clause: 
After the cell is sealed, it is cased with a metal skin. 
The subject of the time clause, the sell, is the same as the subject of the 
main clause, it. When this happens we can rewrite the time clause using the –
ING part of the verb. 
 After being sealed, the cell is cased with a metal skin. 
Rewrite these sentences by reducing the time clause in all those ones 
where both subjects are the same. Not all the time clause can be reduced. 
1. After the resistors are sorted, they are marked to indicate their 
values. 
2. Before you service an oscilloscope, you should discharge all large 
electrolytic capacitors. 
3. Immediately after the pulse is transmitted, the antenna switch is 
closed to the receiver. 
4. Before the signal is applied to the Y plates, it must be amplified. 
5. The signal is amplified after it is rectified. 
Before the operator signals off, he repeats his call sign. 
oscillator 
acceptor 
circuit 
mixer intermediate 
frequency 
amplifier 
detector audio 
amplifier 
 50 
* Task 6: Link pairs of instructions, using reduced time clauses. (Homework): 
Example: 
1. Switch off the main supply. 
2. Remove the fuses. 
→ Having switched off the main supply, remove the fuses. 
1. Set the controls in the recommended positions. 
2. Switch on. 
3. Allow a few minutes to warm up. 
4. Advance the brightness control until the trace appears. 
5. Centralize the trace with the X and Y shift controls. 
6. Adjust the focus control for a clear, sharp trace. 
7. Switch to the ac input. 
8. Connect the input leads. 
9. Increase the Y gain control to obtain a convenient size of waveform. 
10. Adjust the time base controls to obtain a clear waveform. 
PART 3: FURTHER READING: 
Global warming is possibly the most severe environmental issue faced by 
civilization today. The risk posed by its effects has been described in terms of 
environmental disaster due to huge future climate changes. Global warming is 
the increasing of the world’s temperatures, which results in melting of the polar 
ice caps and rising sea levels. It is caused by the release into the atmosphere of 
so - called “greenhouse” gases, which form a blanket and refl ect heat back to the 
earth’s surface, or hold heat in the atmosphere. The most infamous greenhouse 
gas is carbon dioxide (CO2), which once released remains in the atmosphere for 
500 years, so there is a constant build - up as time progresses. The exact extent 
of the contribution arising from man’s activities may be uncertain, but in any 
case it is vital to keep it to a minimum and conserve fossil fuel reserves, i.e. 
minimize greenhouse gas emissions. A major cause of CO2 emission is in the 
generation of electricity at power stations. The CO2 emission factor (kg of CO2 
emitted per kWh of electricity supplied) is dependent on the UK fuel mix for 
electricity generation. For coal - fi red power stations, the fi gure is relatively 
high, for gas - fi red stations it is lower and for hydroelectric, wind power or 
nuclear stations it is zero. Electricity suppliers may claim various mixes of 
generation type and hence differing emission factors, but the best presently 
available average UK fi gure is 0.422 kg CO2/kWh (TEWI Guidelines, 
IOR/BRA). This value is an average of predicted values for 2005 and 2010. It is 
 51 
estimated that refrigeration compressors in the UK consume 12.5 billion kWh 
per year. The global warming potential (GWP) of a gas may be defi ned as an 
index comparing the climate impact of its emission to that of emitting the same 
amount of carbon dioxide. The integrated effect over a fi xed time allows for 
time decay of the substance. A time horizon of 100 years is usually adopted, 
although this is much less than the lifetime of CO2 in the atmosphere. The 
refrigerant only affects global warming if released into the atmosphere. 
 52 
UNIT 7: GETTING A JOB 
Mã bài: MĐ23 - 07 
I. JOB TITLE: 
Sau khi tốt nghiệp, các bạn có thể xin việc ở cơ quan nhà nước (state 
company), công ty tư nhân (private company), công ty liên doanh (joint venture), 
trường học (school) hoặc tự mở doanh nghiệp riêng (self - employed). Dưới đây 
là một số nghề cụ thể mà các bạn có thể làm trong tương lai. 
Automation Engineer 
Electricity Control Engineer 
Electricity System Engineer 
Electrical Equipment Engineer 
Electrical Measure Engineer 
Electrician 
1. Which job do you want to be? 
2. Where do you like working? 
II. READING: 
Quá trình xin việc bắt đầu từ lúc bạn quan tâm tìm đọc những quảng cáo 
tuyển dụng trên báo hoặc niêm yết tại trụ sở các văn phòng giới thiệu việc làm, 
hoặc tại phòng tổ chức của công ty bạn muốn dự tuyển. Bạn cũng có thể tham 
gia vào các hội trợ việc làm (thường được tổ chức vào dịp các bạn tốt nghiệp ra 
trường). Dưới đây là một quảng cáo tuyển dụng trên báo (job ad). Hãy đọc và trả 
lời các câu hỏi dưới đây: 
1. What job is it for? 
2. Where will the person work? 
3. How old is the person? 
4. What qualification, experience will the person need? 
5. If you are interested in this position, what do you have to do? 
“Wanted a skilled electrical engineer for a large engineering/electronics 
company to be built in the industrial complex in Gia Lam - Ha Noi. 
Candidates must have a good degree in electricity and sufficient practical 
experience. Minimum age 23 years. Apply stating full particulars regarding, age, 
experience, salary expected to National Industrial Complex, Gia Lam - Ha Noi 
within 10 days.” 
III. WRITING: APPLYING FOR A JOB: 
 53 
1 
1 
1 
Dưới đây là một mẫu thư xin việc cụ thể. Hãy đọc và trả lời các câu hỏi 
sau đó: 
 15 Hang Dao 
 Ha Noi,Viet Nam 
 20 August 2004 
The Advertiser, 
National Industrial Complex 
Gia Lam, Ha Noi 
Dear Sir, 
I am writing to apply for the post of an electrical engineer advertised in 
“Labour” on the 19 August 2010. 
I graduated from HAUI in June 2011, with a Diploma in Electrical 
Engineering. While in college, I did a part-time job as electrician for Rang 
Dong Lighting Company. Along with it, I was repairing appliances for some 
households when they required. 
Concerning my language ability, I am good at English, and currently I am 
following an English class in the evening language centre. I also have 
computer skills in Word and Excel. I am hard working, creative and ready to 
travel away for work if required. 
A copy of my curriculum vitae is enclosed giving further details and 
testimonial from HIC relating to my character and proficiency in studies. 
I hope to hear from you soon, and to be given the opportunity to present 
myself at an interview. 
Yours respectfully, 
Nguyen Thanh Binh 
1. How many main parts are there in an application letter? 
2. Who write this letter? 
3. Who will the letter be sent to? 
4. What is the post applied? 
5. Underline the sentences or words which can be changed to suit you. 
3
2 
 54 
CURRICULUM VITAE 
Name: Nguyen Thanh Binh 
Day of birth: 26 May 1980 
Address: 15 Hang Dao – Hanoi - Vietnam 
Telephone: 04 857632 
Nationality: Vietnamese 
Marital status: single 
Education: 
19. to 19..: Tran Phu High School 
19. to 20..: Ha Noi Industrial College(Electricity Department) 
2000 – present: graduated from HIC 
Qualification: 
Degree in electricity, Ha Noi Industrial College 
C level certificate: English, Computer 
Extra - curricular: 
Captain - College Volleyball 
President - College Union 
Interests: 
Music (country folk songs and foreign music) 
Volleyball, Basketball and Swimming 
Structure of an application: 
1. The address of the writer 
2. The date of writing the application 
3. The name and address of the employer 
4. The salutation 
5. The introductory or opening paragraph 
6. The body of the application 
7. The concluding paragraph 
8. The subscription 
9. The signature. 
TASK: 
 Write an application for yourself (Use the letter above as a model ) 
.. 
.. 
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IV. SPEAKING: WORK IN PAIRS: 
Sau đây là một số câu hỏi thường gặp khi bạn được mời phỏng vấn xin 
việc. Hai người lập thành một nhóm, hoàn thành các câu hỏi sau. Sau đó, một 
bạn hỏi, bạn kia trả lời câu hỏi. 
1. When / you / leave /college (university)? 
2. You / married? 
3. Where /you /live? 
4. You/tell me / family? 
5. You / work / factory? 
6. You / speak / foreign language? 
7. You / play /sport? 
8. You/go / ever /aboard? 
9. How much /salary /you / expect? 
10. What /your ambition / future? 
11. What/your career objectives (mục tiêu nghề nghiệp) 
12. You mind/travel/away for work? 
 56 
TÀI LIỆU THAM KHẢO 
- Fundamentals (latest edition): ASHRAE Handbook. 
- Refrigeration (latest edition): ASHRAE Handbook. 
- Principles of Refrigeration: Cambridge University Press – Gosney WB. 
- The refrigeration scroll compressor and its application: IOR, 1996-7 – Hundy 
GF and Kulkami S. 
- Heating, ventilating, air conditioning and refrigeration, 2004: CIBSE Guide B. 
- Air conditioning Engineering: Butterworth Heinemann, 2000 – Jones WB.