Shadowing Practice: Air Conditioning System Basics hvacr how does it work - Learn English Speaking with Video
Creating lesson...
1
sponsored by danfoss when we look at a typical refrigeration system we have the compressor
2
the condenser the expansion valve and the evaporator the condenser
3
and the evaporator are both heat exchangers the condenser sits outside the property
4
and the evaporator sits inside the room being cooled the compressor circulates a refrigerant in the pipe work
5
which cycles between all of these components the expansion valve regulates
6
the flow of refrigerant the refrigerant is a specially designed fluid
7
which can change between being a liquid and a gas very easily and that's
8
because it has a very low boiling point for example refrigerant
9
are for 10 a will boil at negative 48 degrees Celsius
10
or negative 55 degrees Fahrenheit although this will change with pressure
11
but if the refrigerant is inside a pipe within a room
12
and the room is at 30 degrees Celsius
13
or 86 degrees Fahrenheit then this will be more than enough to cause it to boil from a liquid into a vapor.
14
By the way if you want some refrigerant charts you can download these for free from our website.
15
I'll link to these in the video description down below.
16
So the The refrigerant is entering the evaporator as a low pressure, low temperature liquid vapor mixture.
17
It flows on the inside of the pipe
18
and at the same time a fan is moving the ambient air of the room over the outside of the pipe.
19
This causes the refrigerant to boil.
20
It will absorb the heat from the air through the pipe wall and then it evaporates.
21
As the refrigerant evaporates, it carries away the heat.
22
It's similar to when we boiled water.
23
The water heats up, it evaporates and turns into steam and carries this heat away.
24
So the air on the outside is entering hot and it's leaving cold.
25
The refrigerant continues to travel through the evaporator, picking up more heat which boils it further until it becomes slightly superheated.
26
This basically means it's now completely gas and doesn't contain any droplets of liquid refrigerant.
27
Liquid damages the compressor, so we want to ensure it can't reach the compressor.
28
The compressor sucks in the refrigerant, which is leaving the evaporator as a low -pressure, low -temperature, slightly superheated vapour.
29
It then squeezes this together into a much smaller space, and so the pressure increases.
30
All the heat which was picked up in the evaporator is now contained in a much smaller volume, so the temperature will increase.
31
This is very important and we will see why in just a moment.
32
But if you've ever pumped up a bicycle tyre, you will notice the pump becomes hotter as it's compressing the air.
33
The refrigerant is then pushed into the condenser where it enters as a high -pressure, high -temperature, superheated vapour.
34
the condenser is located outside
35
and the outside air might be very warm on a summer's
36
day as heat always flows from hot to cold we need to ensure
37
that the refrigerant is hotter than the outside air otherwise the
38
unwanted heat will not be able to leave the refrigerant and leave our system
39
a fan will help to blow ambient air over the condenser to remove this heat
40
so the outside air is entering warm picking up heat
41
and leaving hot as the heat is removed by the air
42
this causes the refrigerant to condense back into a liquid it's a little bit like
43
when steam hits the window on a cold day the window is cold
44
so it condenses the steam from a vapor into a liquid
45
and then this liquid starts to run down the window the
46
refrigerant therefore exits as a high pressure medium temperature saturated liquid
47
and this heads to the expansion valve the expansion valve needs
48
to regulate the amount of refrigerant entering the evaporator to control the superheat
49
if it allows too much refrigerant to flow it can flood the evaporator
50
so the refrigerant doesn't evaporate a liquid reaches the compressor
51
and possibly destroys it but
52
if it lets in too little refrigerant the system won't provide enough cooling and
53
so it operates inefficiently the expansion valve regulates the refrigerant by
54
only allowing it to pass through a small hole this creates
55
a large pressure difference across the valve one side is the high -pressure liquid the other side is almost empty
56
The small hole causes it to almost spray into the evaporator as a part liquid, part vapor mixture.
57
The refrigerant will expand to try and fill the empty space on the other side
58
and this will cause it to drop in pressure as well as temperature.
59
It's a little bit like spraying a deodorant can or a spray paint can.
60
It flows through a small hole causing it to expand as a part vapor
61
and part liquid mixture
62
and then we can feel the can become cooler now the
63
original method to control this was by using a fixed orifice device
64
and you might still find these on the back of your
65
refrigerators the hole within this device was a fixed size
66
so the entire system would simply turn on
67
and off to meet the cooling demand it does work
68
but we can't maintain a stable temperature control
69
because the system is simply turning on
70
and off the next evolution was the thermostatic expansion valve this is still widely used today
71
and it senses the superheat at the outlet through a bulb
72
which is filled with another refrigerant this other refrigerant will expand to close the valve
73
when the superheat is too high and it condenses to open the valve when the superheat is too low.
74
This type of valve needs to be manually calculated and adjusted by a technician.
75
It does work very well but it's prone to mistakes.
76
It also takes a long time to calculate and set up
77
and it is also only adjusted once per service visit which is not ideal.
78
It will also not allow peak performance.
79
However it does work very well and these will continue to be used for many years.
80
And And so the latest evolution is to use electronic expansion valves.
81
These use a controller to measure the exact temperature and pressure
82
and adjust the valve position automatically in real time to ensure optimal performance and maximum system efficiency.
83
Okay that's it for this video but to continue learning about HVAC
84
and refrigeration engineering click on one of the videos on screen now and I'll catch you there for the next lesson.
85
Don't forget to follow us on Facebook, Twitter, LinkedIn, Instagram as well as theengineeringmindset .com
📺 Same Channel
B21
How ELECTRICITY works - working principle
Business EnglishUniversity StudentsWorking Adults
C11
Diodes Explained - The basics how diodes work working principle pn junction
Business EnglishUniversity StudentsWorking Adults
C1Centrifugal Pump Basics - How centrifugal pumps work working principle hvacr
Business EnglishUniversity StudentsWorking Adults
✨ Recommend Video
B21
23 sentences
Working Principle of Chiller Plant | Animation | English
Business EnglishUniversity StudentsWorking Adults
C12
40 sentences
Inside the Relay Controlled SF6 Circuit Breaker: Preventing Arcs and Ensuring Safety
Business EnglishUniversity StudentsWorking Adults
C11
176 sentences
Every Networking Concept Explained | Networking 101 (2026)
Business EnglishUniversity StudentsWorking Adults
B21
234 sentences
Your House Is Making You Sick (15 Solutions)
Business EnglishUniversity StudentsWorking Adults
C11
166 sentences
What's The Best Supercharger? Roots vs Centrifugal vs Twin-Screw vs Electric
Business EnglishUniversity StudentsWorking Adults
C194 sentences
Transient Thermal Analysis in ANSYS AIM
Business EnglishUniversity StudentsWorking Adults
C11
254 sentences
REVIT 2023 FOR MEP - SYSTEM PIPING
Business EnglishUniversity StudentsWorking Adults
C11
339 sentences
Introduction to HPLC - Lecture 1: HPLC Basics
Business EnglishUniversity StudentsWorking Adults
C11
64 sentences
What is SCADA?
Business EnglishUniversity StudentsWorking Adults
C17
60 sentences
What is SMT (Surface Mount Technology)? PCB Assembly (Part 2)
Business EnglishUniversity StudentsWorking Adults
C11
50 sentences
0.0.1 How to become a CAE Engineer CAE | What are the ways to become a CAE Engineer as a fresher
Business EnglishUniversity StudentsWorking Adults
Vocabulary and speaking notes for this lesson
This speaking lesson is built on the video “Air Conditioning System Basics hvacr how does it work”. The speaker keeps coming back to these words: refrigerant, liquid, valve, heat, evaporator. This video has 85 sentences and 1097 words to shadow. The speech runs for 7:15. The speaker talks at a natural 151 words per minute, close to everyday conversation. Only 77% of the words are among the 3,000 most common in English, so the vocabulary is demanding.
Key vocabulary in this video
15 words from the video worth learning, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| liquid noun | /ˈlɪk.wɪd/ | A substance that is flowing, and keeping no shape, such as water; a substance of which the molecules, while not tending to separate from one another like those… |
| valve noun | /ˈvælv/ | A device that controls the flow of a gas or fluid through a space, such as a pipe, manifold, or plenum. |
| boil verb | /bɔɪ(ə)l/ | To heat to the point where it begins to turn into a gas. |
| pipe noun | /ˈpaɪp/ | A wind instrument consisting of a tube, often lined with holes to allow for adjustment in pitch, sounded by blowing into the tube. |
| vapor noun | /ˈveɪpɚ/ | Cloudy diffused matter such as mist, steam or fumes suspended in the air. |
| expand verb | /ɪkˈspænd/ | To change (something) from a smaller form or size to a larger one; to spread out or lay open. |
| mixture noun | /ˈmɪkst͡ʃɚ/ | The act of mixing. |
| spray noun | /spɹeɪ/ | A fine, gentle, dispersed mist of liquid. |
| adjust verb | /əˈd͡ʒʌst/ | To modify. |
| regulate verb | /ˈɹɛɡ.jə.leɪt/ | To dictate policy. |
| evolution noun | /ˌiːvəˈluːʃ(ə)n/ | A manoeuvre of troops or ships. |
| pump noun | /pʌmp/ | A device for moving or compressing a liquid or gas. |
| calculate verb | /ˈkælkjʊleɪt/ | To determine the value of something or the solution to something by a mathematical process. |
| ambient adjective | /ˈæm.bi.ənt/ | Encompassing on all sides; surrounding; encircling; enveloping. |
| stable noun | /ˈsteɪ.bəl/ | A building, wing or dependency set apart and adapted for lodging and feeding (and training) ungulates, especially horses. |
Phrasal verbs you will hear
| Word | Pronunciation | Meaning |
|---|---|---|
| pick up verb | To lift; to grasp and raise. | |
| carry away verb | To steal; to take away. | |
| heat up verb | To heat, to cause to become hotter. | |
| pass through verb | To go through, to travel through, to transit or lie across a place or from one place to another. | |
| run down verb | To hit someone with a car or other vehicle and injure or kill them. | |
| set up verb | /ˌsɛt ˈʌp/ | To make ready for use. |
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | being cooled · was picked · is located |
| Relative clauses who / which + clause — extra information about a person or thing | refrigerant, which is · heat which was · visit which is |
Pronunciation to watch
The speaker uses 9 contractions and reduced forms, such as can't, doesn't, I'll. Say them the short way, as you hear them.
- The “sh” and “zh” sounds: evolution /ˌiːvəˈluːʃ(ə)n/, efficiency /ɪˈfɪʃ.ən.si/, specially /ˈspɛʃəli/, technician /tɛkˈnɪʃən/
- Long words — get the stress right: evolution /ˌiːvəˈluːʃ(ə)n/, efficiency /ɪˈfɪʃ.ən.si/, manually /ˈmænj(u)əliː/, refrigerator /ɹɪˈfɹɪd͡ʒ.əˌɹeɪ.tɚ/, evaporator /ɪˈvæp.ə.ɹeɪt.ɚ/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like liquid, valve, boil.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.