Shadowing Practice: Air Conditioning System Basics hvacr how does it work - Learn English Speaking with Video

Les maken...
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sponsored by danfoss when we look at a typical refrigeration system we have the compressor
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the condenser the expansion valve and the evaporator the condenser
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and the evaporator are both heat exchangers the condenser sits outside the property
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and the evaporator sits inside the room being cooled the compressor circulates a refrigerant in the pipe work
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which cycles between all of these components the expansion valve regulates
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the flow of refrigerant the refrigerant is a specially designed fluid
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which can change between being a liquid and a gas very easily and that's
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because it has a very low boiling point for example refrigerant
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are for 10 a will boil at negative 48 degrees Celsius
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or negative 55 degrees Fahrenheit although this will change with pressure
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but if the refrigerant is inside a pipe within a room
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and the room is at 30 degrees Celsius
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or 86 degrees Fahrenheit then this will be more than enough to cause it to boil from a liquid into a vapor.
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By the way if you want some refrigerant charts you can download these for free from our website.
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I'll link to these in the video description down below.
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So the The refrigerant is entering the evaporator as a low pressure, low temperature liquid vapor mixture.
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It flows on the inside of the pipe
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and at the same time a fan is moving the ambient air of the room over the outside of the pipe.
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This causes the refrigerant to boil.
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It will absorb the heat from the air through the pipe wall and then it evaporates.
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As the refrigerant evaporates, it carries away the heat.
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It's similar to when we boiled water.
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The water heats up, it evaporates and turns into steam and carries this heat away.
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So the air on the outside is entering hot and it's leaving cold.
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The refrigerant continues to travel through the evaporator, picking up more heat which boils it further until it becomes slightly superheated.
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This basically means it's now completely gas and doesn't contain any droplets of liquid refrigerant.
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Liquid damages the compressor, so we want to ensure it can't reach the compressor.
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The compressor sucks in the refrigerant, which is leaving the evaporator as a low -pressure, low -temperature, slightly superheated vapour.
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It then squeezes this together into a much smaller space, and so the pressure increases.
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All the heat which was picked up in the evaporator is now contained in a much smaller volume, so the temperature will increase.
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This is very important and we will see why in just a moment.
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But if you've ever pumped up a bicycle tyre, you will notice the pump becomes hotter as it's compressing the air.
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The refrigerant is then pushed into the condenser where it enters as a high -pressure, high -temperature, superheated vapour.
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the condenser is located outside
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and the outside air might be very warm on a summer's
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day as heat always flows from hot to cold we need to ensure
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that the refrigerant is hotter than the outside air otherwise the
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unwanted heat will not be able to leave the refrigerant and leave our system
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a fan will help to blow ambient air over the condenser to remove this heat
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so the outside air is entering warm picking up heat
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and leaving hot as the heat is removed by the air
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this causes the refrigerant to condense back into a liquid it's a little bit like
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when steam hits the window on a cold day the window is cold
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so it condenses the steam from a vapor into a liquid
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and then this liquid starts to run down the window the
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refrigerant therefore exits as a high pressure medium temperature saturated liquid
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and this heads to the expansion valve the expansion valve needs
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to regulate the amount of refrigerant entering the evaporator to control the superheat
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if it allows too much refrigerant to flow it can flood the evaporator
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so the refrigerant doesn't evaporate a liquid reaches the compressor
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and possibly destroys it but
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if it lets in too little refrigerant the system won't provide enough cooling and
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so it operates inefficiently the expansion valve regulates the refrigerant by
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only allowing it to pass through a small hole this creates
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a large pressure difference across the valve one side is the high -pressure liquid the other side is almost empty
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The small hole causes it to almost spray into the evaporator as a part liquid, part vapor mixture.
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The refrigerant will expand to try and fill the empty space on the other side
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and this will cause it to drop in pressure as well as temperature.
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It's a little bit like spraying a deodorant can or a spray paint can.
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It flows through a small hole causing it to expand as a part vapor
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and part liquid mixture
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and then we can feel the can become cooler now the
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original method to control this was by using a fixed orifice device
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and you might still find these on the back of your
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refrigerators the hole within this device was a fixed size
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so the entire system would simply turn on
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and off to meet the cooling demand it does work
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but we can't maintain a stable temperature control
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because the system is simply turning on
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and off the next evolution was the thermostatic expansion valve this is still widely used today
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and it senses the superheat at the outlet through a bulb
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which is filled with another refrigerant this other refrigerant will expand to close the valve
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when the superheat is too high and it condenses to open the valve when the superheat is too low.
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This type of valve needs to be manually calculated and adjusted by a technician.
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It does work very well but it's prone to mistakes.
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It also takes a long time to calculate and set up
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and it is also only adjusted once per service visit which is not ideal.
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It will also not allow peak performance.
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However it does work very well and these will continue to be used for many years.
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And And so the latest evolution is to use electronic expansion valves.
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These use a controller to measure the exact temperature and pressure
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and adjust the valve position automatically in real time to ensure optimal performance and maximum system efficiency.
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Okay that's it for this video but to continue learning about HVAC
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and refrigeration engineering click on one of the videos on screen now and I'll catch you there for the next lesson.
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Woordenschat en spreektips bij deze les

Deze spreekles is gebaseerd op de video “Air Conditioning System Basics hvacr how does it work”. Deze woorden komen het vaakst terug: refrigerant, liquid, valve, heat, evaporator. Deze video bevat 85 zinnen en 1097 woorden om na te spreken. Het gesproken deel duurt 7:15. De spreker praat in een natuurlijk tempo van ongeveer 151 woorden per minuut, dicht bij een alledaags gesprek. Slechts 77% van de woorden hoort bij de 3.000 meest gebruikte Engelse woorden, dus de woordenschat is pittig.

Belangrijke woorden in deze video

15 woorden uit de video die het leren waard zijn, met uitspraak en betekenis:

WoordUitspraakBetekenis
liquid zelfstandig naamwoord/ˈlɪk.wɪd/vloeistof
valve zelfstandig naamwoord/ˈvælv/ventiel
boil werkwoord/bɔɪ(ə)l/koken, aan de kook brengen
pipe zelfstandig naamwoord/ˈpaɪp/fluit
vapor zelfstandig naamwoord/ˈveɪpɚ/damp
expand werkwoord/ɪkˈspænd/vergroten, uitbreiden
mixture zelfstandig naamwoord/ˈmɪkst͡ʃɚ/mengen
adjust werkwoord/əˈd͡ʒʌst/aanpassen, verstellen
regulate werkwoord/ˈɹɛɡ.jə.leɪt/regelen
evolution zelfstandig naamwoord/ˌiːvəˈluːʃ(ə)n/evolutie
pump zelfstandig naamwoord/pʌmp/pomp
calculate werkwoord/ˈkælkjʊleɪt/berekenen, uitwerken
stable zelfstandig naamwoord/ˈsteɪ.bəl/stal, paardenstal
lesson zelfstandig naamwoord/ˈlɛs.ən/les
ideal bijvoeglijk naamwoord/aɪˈdi(ə)l/ideaal, optimaal

Phrasal verbs die je zult horen

WoordUitspraakBetekenis
pick up werkwoordoppakken, optillen
run down werkwoordaanrijden
set up werkwoord/ˌsɛt ˈʌp/bereiden, voorbereiden

Grammatica in deze video

De structuren die de spreker het meest gebruikt, met de exacte woorden uit de video:

StructuurIn de video
Lijdende vorm be + voltooid deelwoord — het gaat om wat er gebeurt, niet om wie het doetbeing cooled · was picked · is located
Betrekkelijke bijzinnen who / which + zin — extra informatie over een persoon of dingrefrigerant, which is · heat which was · visit which is

Uitspraak om op te letten

De spreker gebruikt 9 samentrekkingen en verkorte vormen, zoals can't, doesn't, I'll. Spreek ze kort uit, zoals je ze hoort.

  • De klanken “sh” en “zh”: evolution /ˌiːvəˈluːʃ(ə)n/, efficiency /ɪˈfɪʃ.ən.si/, specially /ˈspɛʃəli/, technician /tɛkˈnɪʃən/
  • Lange woorden — let op de klemtoon: evolution /ˌiːvəˈluːʃ(ə)n/, efficiency /ɪˈfɪʃ.ən.si/, manually /ˈmænj(u)əliː/, refrigerator /ɹɪˈfɹɪd͡ʒ.əˌɹeɪ.tɚ/, evaporator /ɪˈvæp.ə.ɹeɪt.ɚ/

Klanken die Nederlandstaligen lastig vinden:

  • Stemhebbende eindmedeklinker — /b/, /d/, /g/, /z/, /v/ niet verscherpen: liquid /ˈlɪk.wɪd/, valve /ˈvælv/, expand /ɪkˈspænd/, flood /flʌd/, fluid /ˈflu.ɪd/
  • /æ/ — opener dan de Nederlandse “e”: valve /ˈvælv/, expand /ɪkˈspænd/, calculate /ˈkælkjʊleɪt/, ambient /ˈæm.bi.ənt/, absorb /æbˈsɔɹb/
  • /g/ — een harde plofklank, geen Nederlandse “g”: regulate /ˈɹɛɡ.jə.leɪt/, exit /ˈɛɡzət/

Zo oefen je met deze video

  1. Luister de hele video één keer zonder te spreken en noteer de woorden die je niet kent.
  2. Begin op 0,75× snelheid, spreek zin voor zin na en ga terug naar normale snelheid zodra het makkelijk gaat.
  3. Neem jezelf op en vergelijk met het origineel; let daarbij op woorden als liquid, valve, boil.

Wat is de Shadowing-techniek?

Shadowing is een wetenschappelijk onderbouwde taalleermethode die oorspronkelijk is ontwikkeld voor professionele tolkentraining en gepopulariseerd door polyglot Dr. Alexander Arguelles. De methode is eenvoudig maar krachtig: je luistert naar native Engelse audio en herhaalt het onmiddellijk hardop — als een schaduw die de spreker volgt met slechts 1–2 seconden vertraging. In tegenstelling tot passief luisteren of grammaticadrills, dwingt shadowing je hersenen en mondspieren om echte spraakpatronen tegelijkertijd te verwerken en te reproduceren. Onderzoek toont aan dat het de uitspraaknauwkeurigheid, intonatie, ritme, verbonden spraak, luisterbegrip en spreekvaardigheid aanzienlijk verbetert — waardoor het een van de meest effectieve methoden is voor IELTS Speaking-voorbereiding en echte Engelse communicatie.

Shadowing-techniek: lees de volledige stap-voor-stap-gids →