REFRIGERATION SYSTEM| (PART-1)|
Summary
TLDRIn this educational video, narrator Ravi Gupta introduces the fundamental principles of refrigeration systems, focusing on the vapor compression cycle. He outlines the four main components: compressor, condenser, expansion valve, and evaporator, explaining their roles in the refrigeration process. The script delves into the system's pressure and temperature dynamics, safety devices, and the heat transfer process, all crucial for understanding the efficiency and performance of refrigeration systems.
Takeaways
- 🔧 The refrigeration system operates on the vapor compression cycle, which involves a closed loop of components.
- 🔄 The four main components of a refrigeration system are the compressor, condenser, expansion valve, and evaporator.
- 📈 The compressor's role is to raise the saturation temperature of the refrigerant, preparing it for cooling in the condenser.
- 🌡 After compression, the refrigerant's temperature increases, and it is then cooled in the condenser, changing from gas to liquid form under high pressure.
- 💧 The expansion valve is a pressure controller that reduces the pressure from high to low, facilitating the transition from liquid to gas form.
- 🔄 The system can be divided into high-pressure and low-pressure sections, with the evaporator and compressor on the low-pressure side and the condenser on the high-pressure side.
- 🛡️ Safety devices such as the master solenoid valve and dryer are integral to the system to prevent faults and maintain proper operation.
- 🌡️ The thermostatic expansion valve plays a crucial role in controlling the pressure and temperature of the refrigerant as it enters the evaporator.
- 🌡️ The evaporator extracts heat from the surroundings, cooling the area and causing the refrigerant to boil off and convert from liquid to gas.
- 🔄 The defrost element helps maintain efficient heat transfer by periodically defrosting the evaporator coil to prevent ice buildup.
- 📊 Understanding the pressure-enthalpy diagram is essential for visualizing the heat transfer and work processes within the refrigeration cycle.
Q & A
What is the basic principle that refrigeration systems work on?
-Refrigeration systems work on the principle of the vapor compression cycle.
What are the four basic components of a refrigeration system?
-The four basic components of a refrigeration system are the compressor, condenser, expansion valve, and evaporator.
What is the primary function of a compressor in a refrigeration system?
-The primary function of a compressor is to raise the saturation temperature of the refrigerant so that it can be cooled by the condenser.
How does the condenser cool the refrigerant?
-The condenser cools the refrigerant by either using sea water or fresh water, changing its vapor form into a liquid form.
What role does the expansion valve play in the refrigeration system?
-The expansion valve acts as a pressure controller, converting the high-pressure refrigerant into a low-pressure refrigerant, facilitating the transition from liquid to gas form.
How does the refrigerant change from liquid to gas in the evaporator?
-As the refrigerant enters the evaporator, it extracts heat from the environment, boiling off and converting from a low-pressure liquid to a gas.
What is the purpose of the high-pressure cutout in a refrigeration system?
-The high-pressure cutout is a safety device that prevents the system from pressurizing excessively by cutting off the flow if the valve before the condenser is set.
What is the function of a dryer in the refrigeration system?
-The dryer is used to eliminate any gas, moisture, or oil particles that might be carried over from the compressor, ensuring clean refrigerant flow.
How does a thermostatic expansion valve control the refrigerant flow?
-A thermostatic expansion valve monitors the conditions inside the evaporator and adjusts the opening to control the flow of refrigerant based on the sensed temperature.
What is the purpose of the defrost element in the evaporator?
-The defrost element is provided to periodically defrost the evaporator coil, preventing the unwanted accumulation of ice and ensuring efficient heat transfer.
How is the coefficient of performance (COP) of a refrigeration system determined?
-The COP is determined by the ratio of the heat energy received (from the environment) to the heat energy equivalent of the work done (compression work plus heat rejected in the condenser).
Outlines
🌀 Introduction to Marine Refrigeration Systems
In this introductory paragraph, the narrator, Ravi Gupta, welcomes viewers to the Marine Engineering Hub and sets the stage for a discussion on refrigeration systems. The focus is on the vapor compression cycle, which is fundamental to refrigeration systems. Gupta outlines the four main components of a refrigeration system: the compressor, condenser, expansion valve, and evaporator. He explains that the system operates in a closed cycle, with the refrigerant vapor being compressed in the compressor, cooled in the condenser, and then expanded through the valve to evaporate and absorb heat. The paragraph also touches on the high-pressure and low-pressure zones within the system and the role of the expansion valve as a pressure controller.
🔧 Safety and Operational Components of a Refrigeration System
This paragraph delves into the operational sequence and safety features of a refrigeration system. It begins with the refrigerant vapor exiting the evaporator and entering the compressor, where it is compressed. The paragraph mentions a high-pressure cutout as a safety device to prevent over-pressurization before the condenser. The refrigerant is then cooled in the condenser, either by seawater or freshwater, and collected in a receiver unit. The liquid refrigerant passes through a master solenoid valve, a dryer to remove impurities, and a thermostatic expansion valve, which lowers the pressure and prepares the refrigerant for evaporation. The paragraph also discusses the role of the master solenoid in preventing refrigerant flow in case of compressor faults and the function of the thermostatic solenoid in regulating the flow based on evaporator temperature. Additionally, a defrost element is mentioned to maintain efficient heat transfer by preventing ice accumulation on the evaporator coil.
📊 Understanding the Vapor Compression Cycle with P-H Diagram
In the final paragraph, the focus shifts to understanding the vapor compression cycle through a pressure-enthalpy (P-H) diagram. The diagram includes lines representing absolute temperature, entropy, saturated liquid, and saturated vapor. The paragraph explains the process of compression, condensation, expansion, and evaporation within the cycle. It describes how the pressure and temperature of the refrigerant change as it moves through the system, from being compressed and cooled in the condenser to expanding and evaporating in the evaporator. The paragraph also explains the areas under the P-H diagram that represent the heat energy extracted from the environment, the work done by the compressor, and the heat rejected in the condenser. The coefficient of performance is briefly mentioned, relating to the efficiency of the refrigeration system. The paragraph concludes by encouraging viewers to ask questions if they have any doubts.
Mindmap
Keywords
💡Refrigeration System
💡Vapor Compression Cycle
💡Compressor
💡Condenser
💡Expansion Valve
💡Evaporator
💡High Pressure System
💡Low Pressure System
💡Safety Devices
💡Thermostatic Expansion Valve
💡Coefficient of Performance (COP)
Highlights
Refrigeration systems operate on the principle of the vapor compression cycle.
The refrigeration system consists of four basic components: compressor, condenser, expansion valve, and evaporator.
The refrigeration cycle is a closed system with the refrigerant vapor being compressed in the compressor.
The temperature of the refrigerant increases after compression, which allows it to be cooled by the condenser.
The condenser cools the refrigerant using either seawater or freshwater, changing its state from gas to liquid.
The expansion valve acts as a pressure controller, reducing the pressure from high to low.
The refrigeration system can be subdivided into high-pressure and low-pressure systems.
The compressor increases the pressure of the refrigerant, which is in vapor form, and then it is cooled by the condenser.
The refrigerant, after being cooled and converted to liquid form, still remains under high pressure.
The expansion valve converts the high-pressure liquid refrigerant to a low-pressure liquid form.
The evaporator extracts heat from the environment, causing the refrigerant to boil off and convert from low-pressure liquid to gas.
Safety devices such as the high-pressure cutout prevent system pressurization before the condenser.
The master solenoid valve prevents the flow of refrigerant if a fault occurs in the compressor.
A dryer is used to eliminate any gas, moisture, or oil particles carried over from the compressor.
The thermostatic expansion valve controls the pressure and temperature of the refrigerant entering the evaporator.
A defrost element is provided to periodically defrost the evaporator coil, preventing ice accumulation.
The vapor compression cycle is represented graphically with absolute temperature and entropy, showing the process of compression, condensation, expansion, and evaporation.
The coefficient of performance in a refrigeration system can be understood through the heat energy received, work done, and heat energy rejected.
Pressure and enthalpy graphics illustrate the heat rejected, compression, heat extracted, and expansion processes in the refrigeration system.
Transcripts
friend welcome to marine engineering hub
this is your narrator
ravi gupta today we're gonna talk about
refrigeration system basically
the refrigeration system work on a
principle of
vapor compression cycle what is the
waver compression cycle
i will talk in the later slide
first before starting a refrigeration
system
i will tell you that the refrigeration
system consists of four basic components
first is the compressor
second is the condenser third main
expansion valve
and fourth one is the evaporator so
as you can see this is the compressor
this is the condenser this is the
expansion valve and this is the
evaporator
after that we i will take you to the
other slide
like this before that we need to
understand the
basic concept first is that as you can
see the whole thing
the whole diffusion system is a in
close cycle okay and the refrigeration
vapor coming out from the evaporator is
been
compressed here in compressor okay
and after being compressed the
temperature
of the refrigerant getting raised up
as the temperature of the refrigerant
getting raised up
it has been cooled down by the condenser
either by the mean of sea water or by
fresh water as it getting cooled down
the gas form of refrigerant is changed
into the liquid form
and that liquid form is been converted
into the gas form by
through help of expansion valve the
expansion valve
is a pressure controller which control
which
drop the pressure from high to low
and as it extract the heat from the
evaporator
it convert it form from liquid to
gas okay this is a basic
synopsis of a refrigeration system we
will see
later slide how the whole thing work
first let's see here what i've written
compressor
the main function of a compressor is to
raise the saturation temperature of a
refrigerant
so that it can be cooled by the
condenser
okay so the temperature of the
refrigerant
is been increased so that it can be
cooled by the condensate for that reason
the compression is provided after that
what is happening the
raised saturation temperature of a
represent is cooled by condenser
either by fresh water or sea water to
change its vapor from
one thing i want to tell you that one
thing you need to mine
that the whole system
can also be subdivided into two part
high pressure system
and low pressure system from evaporation
from here to here
this part is a low pressure
thing okay the thing the gas is in low
pressure
zone and from discharge of a compressor
to the inlet of expansion wall this area
is high pressure
basically what is happening as the
represent
is increasing the sorry as a compressor
is increasing the pressure
of the refrigerant it is in vapor form
and
high pressure after it has been cooled
by condenser
it is converted into liquid form but
still it is a high pressure
after that as it passes your expansion
valve
expansion valve is a pressure controller
which converts the high
pressure to low pressure zone but still
it is in liquid form so here this till
the condenser from here
to here this thing is in gas form
here to here it is in liquid form
from expansion valve to the entry of
evaporator
low pressure evaporate
refrigerant is entering the evaporator
and
that is been extracting the heat from
the environment
and converting it into the gas form and
that is going to dug into the compressor
okay now let's see on the bigger system
as you can see the four component here
is one is the compressor condenser
evaporator and that is the expansion bar
along with it it consists of various
component safety device
so first let's see suppose the
represent is coming out from the
evaporator and it is going to
compression
compressor is compressing the
refrigerant gas
as it is compressing the diffusion gap
it is provided with the cutout that if
the valve before the condenser is set
at that time the system this line
may get pressurized to prevent that hp
cutout is provided
okay so the cut out
a safety device provided here as the
refrigerant
is getting compressed now the
high pressure refrigerant gas
form will go and will be cooled in the
condenser
by sea water or it can also be cooled by
a
fresh water and as it is been
cooled the gas form of refrigerant
having high pressure
will be collected in a receiver unit
in liquid form from here the liquid form
the diffusion gas will flow and
as it flow it will go past through a
master solenoid
and then through a dryer so that to
eliminate
any gas or any miss particle or water
particle
or any carryover of the oil particles
of the compressor and through the siphon
class
it will go to solenoid and through a
thermostatic expansion valve
it will convert itself from a high
pressure liquid refrigerant to a low
pressure
liquid refrigerant and as it enter the
evaporator it will extract the heat
from the surrounding from the different
area and
as it extracts the heat it will boil off
and as it boils up it will convert into
a gas form
and it will again go to the compressor
section now i have bypassed
many of the safety device now i will
tell about the
safety device here master
sonol is provided which will prevent
the operation of the
refrigerant which which will prevent the
flow of a refrigerant if any fault occur
in a compressor
as you can see the master solenoid valve
get its signal from a motor controller
or a device which will assess the
condition of the lp and hp
if there is any cut out lp and hp
in that case it will prevent the
starting of the master
solenoid and as the master solar will
close it will prevent the flow of
refrigerant okay now after the condenser
the refrigerant will flow and now will
pass through a dryer this dryer as i
have told is provided so that it can
extract any oil particle or mixed
particle of the
diffusion after that through
here it will pass through a solenoid
this solenoid is a thermostatic control
solenoid
this will come into operation by
monitoring the
condition of the inside the evaporator
if the evaporator temperature inside
is very cool down in that case the
solenoid will be
in closed position but if the
sensing ball says that the temperature
of
inside the refrigerant is high
in that case it will cause the
opening of the solenoid as the solenoid
will open
it will pass through a thermostatic
expansion work
and after the thermostatic expansion
valve it will go to a evaporator
now as the diffusion flow in the
evaporator
it will extract the heat means basically
as it is extracting the heat it is
making the surrounding temperature
of the that area getting cooled
and as it getting cooled it is getting
the refrigerant is getting boiled off
and converting it form from low pressure
liquid refrigerant to a high pressure
liquid refrigerant sorry low pressure
liquid refrigerant to a gas
gas low pressure liquid gas
refrigerant okay now here as you can see
here is a defrost element is provided
that the first element is provided so
that from
time to time the epervator coil
can be defrosted to prevent
the unwanted accumulation of ice over
the surface
so that a good amount of heat transfer
can always take
place okay now i hope you understand
the whole thing
okay now as you can see this is a
vapor compression cycle here this one
represents
the absolute temperature and this one
represent the entropy
this one is the saturated liquid line
and this one
is a saturated vapor line okay this one
is a compression this one is the
condition condensation
and this one is the ipad version and
this one is the
expansion okay so as you can see
from after the evaporation
after the as the gas revenue is coming
out from epa water the pressure is been
increased
and as the pressure is increased this is
the work done by compression
and after that as it has been cooled
down by the condenser
it is getting temperature is getting
down and after that is changing its form
from
gas to liquid form after that
it is again change so as it passes
through a
thermostatic expansion valve it is
getting depressed rise from high
pressure to low pressure and then
as it passes to evaporator extracting
heat
and gaining the heat is changing its
form to liquid again back to the
gas okay now as you know
that this one is the
heat extracted from the environment and
this one is the
here is the heat extracted by the
condenser okay now heat energy received
from the coal chamber
is area under av okay this area
heat rejected in the condenser is equal
to
area under cd okay heat
energy equivalent of work done is area
of the figure abcd a b
c d plus area under d
a okay this one d a
is equal to heat energy rejected
area under c d this one
this one whole area whole area minus
heat energy received is equal to area
under av
that one this one okay so
now if anyone asks you what is the
coefficient of performance then
you can see in simple term is that heat
energy received
that is what are the heat energy we have
received
okay this one is equal to heat energy
equivalent to work done what is the work
done
we are doing the work this one okay
so i hope you understand
now through another thing pressure and
enthalpy graphic you can see
that this one is a heat rejected this
one is a compression
this one is the heat extracted and this
one is the
expansion okay so i hope you understand
the basic concept
of a refrigeration system if you have
the and doubt
please do comment below
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