Working of the Refrigeration system (VCRS) Components:
Compressor: Increases refrigerant pressure and temperature.
Condenser: Releases heat from the refrigerant.
Expansion Valve: Lowers the refrigerant pressure and temperature.
Evaporator: Absorbs heat from the air.
Refrigerant: The working fluid in the system, such as R134a.
Control Units: Regulate the system's operation. What is the basic working principle of AC?
How Do Air Conditioners Work? | Air Conditioning System | AC
An air conditioner cools a room by circulating refrigerant through a cycle of evaporation,
compression, condensation, and expansion. The refrigerant absorbs heat from indoor air at the
evaporator coils, releases it outside at the condenser coils, and then cools back down before
repeating the process.
The air inside the room is sucked into the evaporator and it exchanges the heat with the refrigerant
which allows the air in the room to cool down and this air is circulated continuously. This heat
converts the refrigerant into a gas or vapor state. This low-temperature low-pressure super-heated
refrigerant vapor is sucked by the compressor and compressed to a high-temperature and high-
pressure super-heated vapor.
After compression, this gas goes into the condenser to release the heat of the gas and turns into
liquid. The condenser is a type of exchanger which has seawater lines in it. At first, when the
refrigerant goes into the condenser, the temp drops slightly as the refrigerant is super-heated, and
then the refrigerant changes into a slightly low-temperature liquid refrigerant. After that, this high-
pressure refrigerant fluid goes through the drier, and all moisture will be absorbed.
When this high-pressure fluid goes through the thermostatic expansion valve orifice its pressure
suddenly drops due to its volume increases, refrigerant drops to a very low temp pressure and it
becomes a mixture of liquid plus vapor refrigerant and then it goes into the evaporator.
At the initial point of the evaporator pipe, the refrigerant temperature is low but the temperature
continuously increases from absorbing the heat and converting refrigerant liquid to a gas by the
latent heat of the vaporization process. After the evaporator sensing bulb senses the temperature of
vapor to control the thermostatic expansion valve regulator. When the gas temperature is very high it
means more refrigerant is required in the evaporator for cooling and the whole cycle continues.
Two pressure zones are present in the total cycle. From the delivery side of the compressor to the
thermostatic expansion valve, the orifice is a high-pressure line after the orifice to the suction of the
compressor is the low-pressure line.
Charging Refrigeration System
Preparation and Safety of Ship Refrigeration System
Personal Protective Equipment (PPE): Always observe PPE requirements such as wearing safety
goggles, gloves, and protective clothing.
Ventilation: Ensure proper ventilation of the area to avoid refrigerant vapor accumulation.
System Isolation: Separate it from other machinery that belongs to a ship so as not to cause any
accidental action while being charged.
Leak Check: Carry out a detailed leak check across all parts of the system using either a gas or soap
solution leak detector and fix any leakage before you proceed.
Evacuation: Remove air and moisture within the system with the use of a vacuum pump. This is very
crucial since contaminated systems do not run properly when recharged.
3.2:- Connection and Measurement of Refrigeration System in Ship:
Manifold Gauge Set: Connect a manifold gauge set with a high-pressure service port or low-pressure
service port of the system. These allow you to monitor pressures during charging.
Refrigerant Cylinder: Use a charging hose to connect the refrigerant cylinder to the manifold by
ensuring that the cylinder valve is blocked off.
3.3:- Charging Process for Refrigeration System on Ship:
Weights Charging: The majority of on-board ship systems require the use of weight charging. We
could measure the weight of the refrigerant cylinder before and after recharging.
Vapor or Liquid Charging: Depending on the type of refrigerant and design of a system, charging can
be done in vapor form through the low-pressure side or liquid form through the high-pressure side.
Consult the system’s manual to find out.
Gradual Charging: Slowly open the cylinder valve and allow refrigerant to enter the system gradually
while watching the pressure gauges.
Target Pressures: For proper target pressures (suction and discharge) on an operating temperature,
reference to the system’s specifications is required.
3.4:- Verification And Adjustment of Refrigeration System in Ship:
Leak Check: After charging, make another leak check to ensure that no leaks have resulted from it.
System Operation: Switch on for some time monitoring pressures, temperatures, and overall
performance
Refrigerant Charge Adjustment: If it’s not up to spec adjust refrigerant charge whatever it takes This
may involve incrementing or decrementing minute amounts of refrigerant.
What is Refrigerant Recycling?
Cleaning and purifying recovered refrigerant to get rid of impurities like moisture, oil, and dirt is
referred to as refrigerant recycling. This is done to ensure that the refrigerant meets the prescribed
purity standards by such organizations as the Air-Conditioning, Heating, and Refrigeration Institute
(AHRI).
5.1:- Process of Recycling:
The oil separator runs over the collected coolant to get rid of any oils present in the system.
Filtering: Then the coolant has to go through a filter process for it to remove all solid contaminants.
Dehydration: The coolant has to pass a dehydrator stage which removes every trace of water in it.
After distillation, it may have some further refining done on it depending on the type of coolant.
In refrigeration system, the sensing bulb is fitted at the discharge line of the evaporator
which senses the temp of the refrigerant coming from the evaporator. The sensing bulb has the same
refrigerant in a confined space that flows in the main system when the degree of superheat of the
refrigerant is more than the sensing bulb senses it. The refrigerant in the sensing bulb vapourises
which increases the pressure in it and as we know the fluid flows from high pressure to low pressure
region. The refrigerant in the sensing bulb flows through the capillary tube to the Thermostatic
Expansion Valve.
Thermostatic Expansion Valve
The components of a thermostatic expansion valve are:
o The diaphragm
o The pin
o The orifice
o The poppet valve
ALIGNMENT OF SHIP’S PROPELLER SHAFT IS DONE?
o The spring
Working of the Refrigeration system (VCRS) Components:
Compressor: Increases refrigerant pressure and temperature.
Condenser: Releases heat from the refrigerant.
Expansion Valve: Lowers the refrigerant pressure and temperature.
Evaporator: Absorbs heat from the air.
Refrigerant: The working fluid in the system, such as R134a.
Control Units: Regulate the system's operation. What is the basic working
principle of AC?
How Do Air Conditioners Work? | Air Conditioning System | AC
An air conditioner cools a room by circulating refrigerant through a cycle of
evaporation, compression, condensation, and expansion. The refrigerant
absorbs heat from indoor air at the evaporator coils, releases it outside at the
condenser coils, and then cools back down before repeating the process.
The air inside the room is sucked into the evaporator and it exchanges the heat
with the refrigerant which allows the air in the room to cool down and this air
is circulated continuously. This heat converts the refrigerant into a gas or vapor
state. This low-temperature low-pressure super-heated refrigerant vapor is
sucked by the compressor and compressed to a high-temperature and high-
pressure super-heated vapor.
After compression, this gas goes into the condenser to release the heat of the
gas and turns into liquid. The condenser is a type of exchanger which has
seawater lines in it. At first, when the refrigerant goes into the condenser, the
temp drops slightly as the refrigerant is super-heated, and then the refrigerant
changes into a slightly low-temperature liquid refrigerant. After that, this high-
pressure refrigerant fluid goes through the drier, and all moisture will be
absorbed.
When this high-pressure fluid goes through the thermostatic expansion valve
orifice its pressure suddenly drops due to its volume increases, refrigerant
drops to a very low temp pressure and it becomes a mixture of liquid plus
vapor refrigerant and then it goes into the evaporator.
At the initial point of the evaporator pipe, the refrigerant temperature is low
but the temperature continuously increases from absorbing the heat and
converting refrigerant liquid to a gas by the latent heat of the vaporization
process. After the evaporator sensing bulb senses the temperature of vapor to
control the thermostatic expansion valve regulator. When the gas temperature
is very high it means more refrigerant is required in the evaporator for cooling
and the whole cycle continues.
Two pressure zones are present in the total cycle. From the delivery side of the
compressor to the thermostatic expansion valve, the orifice is a high-pressure
line after the orifice to the suction of the compressor is the low-pressure line.
