steam jet refrigeration system full working and a simple way to understand it covering the aspects of heat and refrigeration systems.

1. Steam jet
refrigeration
system
SANIA BAISOYA
A2399819028

2. INTRODUCTION
• The steam jet refrigeration system (also known as
ejector refrigeration system) is one of the oldest
methods of producing refrigeration effect.
• It is a cooling technique which involves usage of
steam and water for cooling purposes.
• This system utilizes mostly low-grade energy and
relatively small amounts of shaft work.
• In this system, water is used as the refrigerant.
• Not used when temperatures below 5°C are
required. Temperatures attained using water as a
refrigerant are in the range which may satisfy air
conditioning, cooling, or chilling requirements.
• Thus, it is widely used in food processing plants and
in some chemical industries for several purposes.

3. WHY IS THIS
UNCONVENTIONAL
TECHNIQUE
PREFERRED ?
Steam jet cooling system is
preferable over conventional
cooling system because:
• Employs a steam injector or
booster instead of mechanical
compressor to compress the
refrigerant to the required
condenser pressure level.
• Water is used as the
refrigerant; environment is
free of CFC's and other
refrigerants which produce
harmful gases leading to
depletion of ozone layer.

4. Principle of steam jet refrigeration system : –
• PRINCIPLE - "The boiling point of a liquid changes with
change in external pressure."
• In normal conditions, pressure exerted on the surface of a
liquid is the atmospheric pressure.
• If this atmospheric pressure is reduced on the surface of a
liquid, by some means, then the liquid will start boiling at
lower temperature, because of reduced pressure.
• Basically ,boiling the water under 100°C by the process of
reducing the pressure on the water surface below
atmospheric pressure.

5. SCHEMATIC
DIAGRAM

6. COMPONENTS OF STEAM JET
REFRIGERATION SYSTEM
• There are various components in this system.
• Evaporator: The evaporator or flash chamber is a large
vessel and is heavily insulated to avoid the rise in
temperature of water due to highly ambient temperature.
• Condenser: Chills the LP, HT air coming from the thermo-
compressor using chilled water as the refrigerating medium.
• Ejector: (replacing compressor) Used to compress the water
vapours coming out of the flash chamber
• Nozzle: It is used to increase the velocity of the steam.

7. WORKING OF A STEAM JET COOLING SYSTEM
• High pressure steam flows to the nozzle from the boiler which is expanded.
• The flash chamber is heavily insulated and is fitted with perforated pipes which spray warm water
coming out of refrigerated space. Some of this water is converted into vapours after absorbing latent
heat from the rest of the water, thereby cooling it.
• Water vapours from the flash chamber drawn along with the high velocity steam jet from the boiler
and it is further compressed in the thermo compressor. This leads to rise in temperature and
pressure of the mixture.
• Then it is fed to the water cooled condenser. The condensate is again fed to boiler as feed water.
• Generally, 1% evaporation of water in the flash chamber is sufficient to decrease the temperature of
chilled water to 6°C.
• Chilled water is circulated by a pump to the point of application.
• The warm water from the load is returned to the flash chamber. The water is sprayed through the
nozzles to provide maximum surface area for cooling.
• The water, which is splashed in the chamber and any loss of cold water at the application, must be
replaced by makeup water added to the cold water circulating system.

9. NOW WHAT IS IT’S COP ?
 The COP may be defined as the ratio of evaporator
refrigeration load to heat input to the boiler as follows:

10. WHAT STEAM JET EJECTORS
ACTUALLY DO?
• High pressure steam from the boiler(generally called primary fluid
or motive steam) is admitted to the steam chest and expanded in
convergent -divergent nozzle to a very low pressure and attains
supersonic velocities in the range of 1000m/s to 1350m/s.
• The flash chamber is connected to the region of low pressure of the
ejector. The water vapour from the flash chamber is entrained in
the high velocity jet of steam and both are mixed in the mixing
section at the constant pressure.
• The velocity of mixture will be super sonic after the completion of
the mixing process. This supersonic steam get a normal shock in
constant area throat of diffuser, resulting in rise of pressure and
subsonic flow. The diverting portion of the diffuser velocity head is
recovered as pressure head and finally high pressure steam is
condensed in condenser.

11. Advantages
• Simple construction
• Vibration free system
• Highly reliable
• Low production cost
• Water is used as a refrigerant which is perfectly
safe.
• Low running cost
• Load variation quickly adjusted
• It is suitable for places where steam is available
such as process industry, steel plant, petroleum
plants, thermal power plants etc.

12. Disadvantages
• Not suitable for water temperature below 5C.
• The maintenance of high vacuum in the
evaporator is necessary for proper functioning of
the system.
• COP is very low.
• Efficiency of ejector is not good.

13. APPLICATION
• Food processing plant for precooling of
vegetables and concentrating fruit etc.
• the removal of paraffin wax from lubricating oils
• Gas plants
• Breweries
• Rubber and vulcanizing industries
• Paper and pulp industries.

14. THANK YOU