How does a Refrigerator work?
Summary
TLDRThis video explains the working principles of modern refrigerators, starting with the basic vapor compression cycle. It highlights key components like the throttling device, evaporator, compressor, and condenser, and describes how cold liquid is circulated to achieve cooling. The video also addresses common issues such as frost buildup and shows how modern solutions like digital inverter compressors improve energy efficiency and temperature control. The digital inverter technology, which allows variable compressor speeds, significantly enhances performance and reduces energy consumption by at least 40%, compared to traditional single-speed compressors.
Takeaways
- 🧊 The basic principle of refrigerators is to pass a colder liquid continuously around the object to be cooled.
- 🌡️ A throttling device, often a capillary tube, is crucial for creating a cold liquid by reducing pressure and causing the refrigerant to evaporate.
- 💧 The refrigerant should be able to change phase with pressure variation at normal temperatures, which is essential for the refrigeration cycle.
- 🔄 The refrigeration cycle involves the refrigerant going through a series of transformations: from liquid to vapor and back to liquid.
- 🌀 An evaporator fan helps maintain different temperature levels inside the refrigerator by circulating the cold refrigerant.
- 🔧 The compressor raises the pressure of the refrigerant back to its initial value after it has been throttled and evaporated.
- 🌡️ The condenser, located outside the refrigerator, converts the high-pressure vapor back into a liquid by releasing heat to the surroundings.
- ❄️ Frost formation in the freezer compartment is a common issue, which can be mitigated by occasional defrosting or using a heating rod.
- 🔧 Modern refrigerators use a compact condenser arrangement and a cooling fan to improve heat rejection and efficiency.
- 🏡 The capillary tube in home refrigerators is often hidden inside the evaporator exit coil, which optimizes the refrigeration effect.
- 🔋 Digital inverter compressors offer variable speed control, leading to smoother temperature management and at least 40% less energy consumption compared to single-speed compressors.
Q & A
What is the basic principle behind the operation of a refrigerator?
-The basic principle of a refrigerator is to pass a colder liquid continuously around the object to be cooled. This creates a cooling effect by absorbing heat from the object.
How is the cold liquid flow achieved inside a refrigerator?
-A cold liquid flow is achieved using a throttling device, like a capillary tube. The refrigerant is in a high-pressure liquid state at the inlet, and as it flows through the tube, the pressure drops, lowering the boiling point and causing part of the refrigerant to evaporate, which cools the remaining liquid.
What role does the compressor play in a refrigerator?
-The compressor raises the pressure of the refrigerant vapor back to its initial high-pressure state after the cooling process. This allows the refrigeration cycle to repeat continuously.
What is the purpose of the condenser in a refrigerator?
-The condenser converts the high-pressure vapor refrigerant into a liquid by releasing heat to the surroundings. This occurs after the refrigerant is compressed and before it returns to the throttling device.
What is the role of the evaporator in the refrigeration cycle?
-The evaporator absorbs heat from the refrigerated space. As the refrigerant passes through the evaporator, it absorbs heat and evaporates, causing the temperature in the space to decrease.
Why does frost form in the freezer compartment, and how is it removed?
-Frost forms when the moisture in the circulating air condenses on the cold evaporator coil. This frost can impede heat transfer, making the refrigerator inefficient. To remove it, modern refrigerators use a heating rod to melt the frost, and the water is collected in a pan at the bottom of the refrigerator.
Why do modern refrigerators have a compact condenser instead of visible condenser fins at the back?
-Modern refrigerators use a compact condenser arrangement with a cooling fan, which achieves the same heat rejection purpose as the older, larger condenser fins. The fan also helps evaporate water from the defrosting process.
Why do some refrigerators only have one visible refrigerant line instead of two?
-Modern refrigerators often have only one visible line because the capillary tube, which carries the cold refrigerant liquid, is routed inside the evaporator exit coil. This design improves the cooling efficiency by bringing the refrigerant temperature down further.
What is the benefit of using a digital inverter compressor in modern refrigerators?
-Digital inverter compressors allow variable speed operation, which leads to smoother temperature control, greater energy efficiency (up to 40% less energy consumption), and increased durability compared to traditional single-speed compressors that switch abruptly between on and off states.
How does the digital inverter compressor control motor speed?
-In a digital inverter compressor, AC power is converted to DC using a controller, which supplies electric power at variable frequencies to control the motor speed accurately. This allows for more precise temperature regulation inside the refrigerator.
Outlines
🧊 How Refrigerators Work: Basic Principles and Components
This paragraph introduces the basic principles behind the operation of refrigerators, which are essential appliances in modern households. It explains that refrigerators work by circulating a colder liquid around the object to be cooled. The liquid's cooling effect is achieved through a device called a throttling device, such as a capillary tube, which causes a significant pressure drop and a subsequent drop in temperature. The process involves converting the refrigerant from a high-pressure liquid to a low-pressure vapor, absorbing heat from the surroundings in the evaporator, and using a compressor to return the refrigerant to its initial state for continuous cooling. The paragraph also mentions issues like frost buildup and the use of a heating rod to remove frost, along with the compact condenser arrangements found in modern refrigerators.
🌡️ Temperature Distribution and Capillary Tube Innovations
This paragraph delves into the temperature distribution within different parts of a refrigerator, highlighting the significance of the capillary tube design in enhancing refrigeration efficiency. It explains that, unlike older designs with visible external lines, modern refrigerators often use a straight capillary tube that runs inside the evaporator exit coil. This setup helps improve the refrigeration effect by reducing the temperature of the refrigerant in the capillary tube, leading to a greater temperature drop and enhanced cooling. The design also ensures that the refrigerant in the evaporator exit line remains in pure vapor form, which is ideal for compressors. Additionally, the paragraph introduces the concept of digital inverter compressors, which adjust compressor speed to maintain a smooth and efficient temperature control inside the refrigerator, reducing energy consumption by at least 40% compared to traditional single-speed compressors.
Mindmap
Keywords
💡Refrigeration
💡Throttling Device
💡Evaporator
💡Compressor
💡Condenser
💡Vapor Compression Cycle
💡Digital Inverter Compressor
💡Heat Transfer
💡Frost Formation
💡Coefficient of Performance (COP)
Highlights
Refrigerators work on the principle of circulating a colder liquid around the object to be cooled.
The throttling device is a crucial component that reduces the pressure of the refrigerant, causing it to evaporate and cool.
As the refrigerant evaporates, it absorbs heat from the surrounding area, which is the basic cooling effect in a refrigerator.
The evaporator is the heat exchanger responsible for maintaining different temperature levels inside the refrigerator.
A compressor raises the pressure of the refrigerant, allowing it to repeat the cooling cycle.
The condenser, located outside the refrigerator, helps convert the high-pressure vapor back into a liquid by releasing heat.
Frost buildup on the evaporator coils reduces refrigerator efficiency, which is countered by occasional defrosting using a heating rod.
Modern refrigerators often use compact condensers with fans to efficiently reject heat and evaporate water from defrosting.
Refrigerators utilize two refrigerant lines: one for cold liquid to the evaporator and another for vapor exit, but only one is visible externally.
In some designs, the capillary tube is positioned inside the evaporator exit line, improving cooling efficiency by exchanging heat.
The capillary tube's contact with the evaporator exit line enhances the refrigeration effect and protects the compressor by ensuring the refrigerant is pure vapor.
A filter dryer is used to remove moisture from the refrigerant to ensure smooth compressor operation.
Digital inverter compressors, unlike older on-off compressors, allow variable speeds, ensuring smoother and more efficient temperature control.
Digital inverter technology converts AC power to DC, allowing variable motor speeds for better energy efficiency.
Refrigerators with digital inverter compressors consume at least 40% less energy than those with single-speed compressors.
Transcripts
have you ever wondered how the
refrigerators in your home work
refrigerators which have become an
integral part of every household work
based on some simple and interesting
scientific principles
[Music]
beginning with the basic refrigerator
model this video will elaborate on the
operation of modern refrigerators along
with the secrets behind their high
energy efficiency
the basic principle of refrigerators is
simple simply pass a colder liquid
continuously around the object to be
cooled
let's see how this continuous cold
liquid flow is achieved inside a
refrigerator
a simple device called a throttling
device is the most crucial component of
refrigerators here a capillary tube is
used as throttling device a cold liquid
is produced using the throttling
phenomenon for effective throttling at
the inlet the refrigerant should be at a
liquid state under high pressure
the throttling device is an obstruction
to the flow so a huge pressure drop
occurs when the liquid flows through it
as the pressure drops the boiling point
of the liquid comes down thus the
refrigerant liquid evaporates the energy
required for such evaporation comes from
the refrigerant so its temperature drops
if you check the temperature across the
throttling device you will notice this
drop
please note that only a portion of the
refrigerant is evaporated here this is
one important property of the
refrigeration fluid it should be able to
change the phase while varying the
pressure under normal temperatures
the next phase is simple just pass this
cold liquid over the body which is to be
cooled
during the heat absorption process the
refrigerant further evaporates and
transforms into pure vapor
since there is phase change during this
process the refrigerant temperature does
not increase this heat exchanger is
called the evaporator
with the help of clever airflow
circulation inside the refrigerator
using an evaporator fan one can maintain
different temperature levels
so we have produced the required
refrigeration effect if we can take this
low pressure refrigerant to the state
before throttling that is high pressure
liquid we will be able to repeat this
process
so the first step is to raise the
pressure
a compressor is used for this purpose
the compressor will raise the pressure
back to its initial value
you can see that a reciprocating type
compressor is used here
however since it is compressing gas
along with pressure the temperature will
also increase this is unavoidable
now the refrigerant is high pressure
vapor to convert it to a liquid stage we
introduce another heat exchanger this
heat exchanger is fitted outside of the
refrigerator thus it will liberate heat
to its surroundings vapor will be
converted to liquid and temperature will
reach a normal level this heat exchanger
is known as a condenser
now the refrigerant is back to its
initial state so it can be fed to the
throttling device again
just by repeating this cycle over and
over we will be able to achieve a
continuous cooling effect this cycle is
more specifically called the vapor
compression cycle
refrigerator performance can be
evaluated using a term called
coefficient of performance
performance is output divided by input
so the coefficient of performance can be
easily defined as follows
this is the most basic refrigerator
possible ever this refrigerator will
work well in theory however
in practice it will face many issues
let's see what these issues are and how
to overcome them
one major issue is the frost developed
in the freezer compartment
the circulated air has moisture content
inside it so when the air comes in
contact with the cold evaporator coil
they will condense and form a frost
around the coil
such ice coating prevents further heat
transfer and the refrigerator becomes
inefficient over time
one great way to solve this issue is to
remove frost occasionally with the help
of a heating rod
this is why you can see a pan and water
condensate at the bottom of your
refrigerator
moreover in modern refrigerators you
won't be able to see the condenser fins
at the back of the refrigerator instead
they use a compact condenser arrangement
this compact arrangement is assisted by
a cooling fan and the same heat
rejection purpose is achieved here the
hot air expelled by the fan can be used
to effectively evaporate the water
condensate formed during the frosting
the improved refrigerator looks like
this
an interesting temperature distribution
in different parts of the refrigerator
is illustrated here
the temperature drop across the
capillary tube is also clearly depicted
here
you can see two refrigerant lines
outside the refrigerators one takes the
cold liquid from the capillary tube to
the evaporator coil and the other the
exit vapor line from the evaporator
however if you check your home
refrigerator you can see only one line
on the outside
why is this the case
the most crucial part of the
refrigerator is the capillary tube which
need not be a spring-like device it can
be a long straight tube as shown
temperature variation in the new
straight capillary tube is depicted here
you see only one line on your home
refrigerator because this straight
capillary tube runs inside the
evaporator exit coil
this simple technique has major
advantages
we know that during the heat absorption
process at evaporator the refrigerant
temperature does not rise only its phase
changes
this means that if we allow the
capillary tube to come into contact with
the evaporator exit line this will bring
down the capillary tube refrigerant
temperature by a great degree
this in effect will lead to greater
temperature drops in the capillary tube
thus creating a better refrigeration
effect
on the other hand the evaporator exit
coil absorbs heat this will ensure that
the refrigerant in the evaporator exit
line has transformed into pure vapor
this is good for compressors which are
designed to handle only pure vapor
a filter dryer is used to remove any
moisture contents in the refrigerant
which might become trapped in the
compressor operation
let us now explore the most recent
innovation in refrigerators which has
transformed modern refrigerators
digital inverter compressors
a compressor is the heart of any
refrigerator and is the device that
gives life to the whole system
you might have noticed that the
compressors in old refrigerators will
either be on or off this is a single
speed technology when the inside
temperature of the refrigerator reaches
an optimum level the compressor will be
turned off when the temperature goes
above a certain limit the compressors
will be turned on
so you can see that the temperature
control inside the refrigerator is not
smooth moreover such abrupt speed
variation of the compressors will lead
to durability issue to the compressor
components
with the help of digital inverter
compressor a variable compressor speed
is possible
thus a smooth and efficient evaporator
temperature control can be achieved here
here the ac power is converted to dc
using a controller the controller then
supplies electric power in variable
frequency to accurately control the
motor speed
the most common motor used in this
technology is a bldc digital inverter
compressor consumes at least 40 percent
less energy compared to the single speed
compressors
we hope this video gives you a clear
insight of the working of a modern
refrigerator we request your support at
patreon.com to make sure our service is
sustainable thank you
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