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D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 1
To Be A Leader In Maritime Education & Training
Refrigeration, Air conditioning
& ventilation
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 2
To Be A Leader In Maritime Education & Training
Refrigeration System Cold Room
The refrigerant is drawn as vapour at low pressure from the evaporator into compressor.
The vapour is compressed in compressor to a high pressure and delivered into coils of condenser in the state of superheated vapour.
Vapour is cooled and condensed into liquid in the condenser at approximately sea water temp.
Liquid still at high pressure passes to thermal expansion valve. Some flashes off into vapour.
The liquid and vapour passes through evaporator where it receives heat to evaporate before being taken into compressor
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 3
To Be A Leader In Maritime Education & Training
Refrigeration System
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 4
To Be A Leader In Maritime Education & Training
Refrigeration, Air Conditioning & Ventilation
Desirable properties of a Refrigerant
Non-corrosive
High critical temperature
(temperature above which refrigerant gas cannot be condensed by pressure)
Non toxic
Non- flammable
Easy leak detection
High latent heat value
Low condensing pressure
( low pressure system to safeguard leakages)
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 5
To Be A Leader In Maritime Education & Training
Refrigeration, Air Conditioning & Ventilation
Properties of refrigerants
Carbon Dioxide
Low specific volume, low critical temperature,
high condensing pressure, low latent heat, non-
toxic
Freon 12 (R12)
High critical temperature, low condensing
pressure,
high latent heat, low specific volume, non-toxic.
Ammonia
High specific volume, toxic, flammable
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 6
To Be A Leader In Maritime Education & Training
Refrigeration, Air Conditioning & Ventilation
Properties of refrigerants
HFC 134a
zero Ozone Depletion Potential (ODP)
some Global Warming Potential (WMP)?
28 psi (2 bars) bp 32 deg F
160 psi (12 bars) bp 115 deg F.
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 7
To Be A Leader In Maritime Education & Training
Refrigeration for Container
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 8
To Be A Leader In Maritime Education & Training
Refrigeration for Cargo
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 9
To Be A Leader In Maritime Education & Training
Air Conditioning System
Provide a comfortable working environment.
Several central units are used to distribute conditioned
air to cabins/space via single duct.
In warm climate, a mixture of fresh and recirculated air
is cooled and dehumidified during its passage over the
refrigeration unit.
In cold climate air mixture is warmed and humidified
either by steam , hot water or electric heating elements.
Temperature and humidity of air is controlled
automatically at the central unit.
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 10
To Be A Leader In Maritime Education & Training
Air Conditioning System
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 11
To Be A Leader In Maritime Education & Training
Ventilation System for Cargo Holds
Ventilators are necessary to give adequate air circulation to under deck spaces and tanks.
The coaming of ventilators are to have a minimum height
above the weather deck of : position 1, exposed freeboard &
superstructure deck within forward 0.25L : 900 mm and
position 2, exposed superstructure deck abaft 0.25L: 760mm
Goose or swan neck type ventilators are mainly used for air
pipes to tanks. The height is not to be less than 760 mm on
freeboard deck and 450 mm on superstructure deck.
Air pipes are placed at opposite end to the filling pipe and
/or at the highest point of the tank.
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 12
To Be A Leader In Maritime Education & Training
Ventilation System for Cargo Holds
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 13
To Be A Leader In Maritime Education & Training
Ventilators
Concept: The coaming height is defined as the
vertical distance from the deck to the
lower edge of the access opening.
For gooseneck vents, the coaming height is measured to the underside of the gooseneck.
Wall vent fitted with an internal baffle, the coaming height is measured to the top of the baffle.
Requirements: In Position 1, minimum coaming height is to be 900mm.
In Position 2, minimum coaming height is 760mm.
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 14
To Be A Leader In Maritime Education & Training
Cargo Holds Ventilation System
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 15
To Be A Leader In Maritime Education & Training
Ventilators
D1MC Semester 2 / ECS / March 2007/LSC /10. Refrigeration, AC & ventilation 16
To Be A Leader In Maritime Education & Training
Cargo Holds Ventilation System