train air conditioing system

7/31/2019 Train Air Conditioing System

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Welcome

to

Air conditioning system


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Why air conditioning ???

Becoz human feels comfort only with somespecified parameter of temperature , humidity &purity & distribution of air in the occupied area , but

outside condition is variable & doesnt fulfill therequirement.


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to control temperature

to control humidity

to supply pure air

to distribute air properly

Remove co2 from occupied area

.

Function of air conditioning system


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Component of air

conditioning systemAir Transfer Equipment ( supply &

distribution of air in the occupied area)

Refrigeration system ( to control thetemperature & humidity of air to be supplied

in the occupied zone)

Electrical Equipments &controls ( tosupply electrical power supply & controlling

all the equipments.


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Condenser

Coils

Condenser

Fans

Compressor

Compartment

Evaporator

CompartmentSupply Air

Blowers

Return Air Compartment

Main component

Emergency

inverter


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SUPPLYAIR

RETURN

AIR

RETURN

AIR

ELEC.CUBICLE

sight glass

Supply fan

condenser

Condenserfan

compressor

Air conditioning System


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Air transfer System

. S .

S .

saloon

Evaporator

Fresh air

Fresh air

Fresh airdamper

Returnair

RATFAT

Supplyfan Supply

fan

filter Air toatmosphere

NextAC

. S .

S .


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High pressure very high temp. vapour

High pressure high temp. liquid

Very Low temp. Low pressuremixture of liquid. & vapour

Low temp. low pressure . vapour

evaporator

Compressor

Condenser

DPC

T-X v/v

Sightglass

Filterdrier

Supplyfan

condenser fan

Refrigeration system

Solenoidv/v


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Refrigeration cycle

T4

T2

T3

Temp.

entropy

1

2

23

4

1

1-2:- compression

2-3 desuperheating

& condensation

3-4 expansion

4-1 evaporation &superheatingT1


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Electrical system


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Electrical system


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Power circuit


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Control circuit


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Programmable Logic Controller

INPUT

1. Circuit breaker status

2. High low pressurecondition

3. Emergency condition

4. Smoke condition

5. Fresh return airtemperature

6. Compressor motorwinding temperature

OUTPUT

1. Mode of working

2. Contactors

energizing3. Damper motor

opening

4. Solenoid valve on /off

5. Unloader on / off

6. Event & datalogging

PLC

TIMS


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Normal Operating Mode

In Normal Operating Mode A/C unit provides cooling and

ventilation, switching automatically by various sub modes to

fulfil specified condition.

Emergency Operating Mode

When 3Ph. Power supply is not available , ac will work in this

mode & will supply fresh air only..

Smoke Mode

In this mode , system shuts off the fresh air intake and provides

full recirculation of return air within the saloon.

Operating modes


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Normal operating sub -modes

Vent mode :-air is supplied inside saloon without any cooling .

COOL2

COOL2

TEMPERATURE

FALLING

TEMPERATURE

RISING

COOL1

COOL1

VENT

VENT

SET POINT

SET POINT +1CO

SET POINT

Set Point + 0.5Co

Set Point + 0.5C

Set Point + 1.0C

Cool-1 mode:-

air is supplied with cooling(only 50% of cooling capacity

is used)

Cool-2 mode:-air is supplied with cooling(100% cooling capacity isused.

24.00 C

24.50 C

250 C


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Different faults Circuit breaker tripping i.e SFB , CBF , CMB tripping:anycircuit breaker gets trips, this fault comes.

CBF-1 or 2 tripped:- system will run as usual with increased discharge pressure

CFB- 1&2 tripped :- system will not run in cool mode

CMB tripped:- system will not run in cool mode

SFB mode:- system will not run in a any mode

High pressure(HP) fault:-when system pressure increase beyond givensafe limit for the system, then system gets tripped. If such instances occur more

than 3times in a hours, then cooling system will shut down.

Low pressure fault:when system pressure decreases beyond given safelimit for the system, cooling system will shut down.


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Different faults

High ambient temperature unloading.:-in case of adverse ambientcondition , to avoid overloading of cooling system , system is unloaded.

RAT/FAT probe fault:-these faults occurs in case of failure of temperatureprobe.

COTS / IAOT getting operated:-these are temperature switches ,installed inside compressor motor winding & inverter area respectively., & getsoperated when temperature exceeds the given limit.& respective system gets

shutdown.


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Cab air conditioning

Capacity:- 5 KW

Single rotary compressor

Single condenser fan

3 Different temperature set point

Manual selection of operating mode

Back mode facility in case of failure


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1. CompressorThe function of the compressor is to pump the refrigerant

through the system and to compress the low pressure, lowtemperature refrigerant into a high pressure high temperature

super heated vapour, to allow condensing to occur.

Type:- Semi-Hermetic Four Cylinder

Reciprocating Suction Gas Cooled

Speed:- 1450 rpm

Swept volume:- 82.21 m3/h

Displacement:- 945 ccm


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2. CondenserThe function of the condenser coil is to reject the heat

from refrigerant absorbed by the evaporator coil and

during the compression process

Type: Copper finned, copper tube,

brass frame heat exchanger

Quantity: 2 per unitAir Flow: 2700 l/s (each coil)


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3. T-X valveThe TX valve regulates the refrigerant flow into the

evaporator coil, expanding the liquid from high pressure to

low pressure, and causing a large drop in refrigerant

temperature.

Refrigerant R22

Factory Superheat 5 K

Max bulb temp. 100 o C

Max working pressure 28bar


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4. Evaporator coilThe prime function of the evaporator compartment

is to deliver conditioned air to the main supply air

duct that services the vehicle

Type: Copper finned, copper tube,

brass frame heat exchanger.

Quantity: 1 per unit.

Air Flow: 1350 l/s

Face Velocity: 2.5 m/s

Cooling Capacity: 41 kW


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5. Dual pressure controller (DPC)

Its function is to switch off the refrigeration system in caseof adverse system condition . It monitors both the high and

low refrigerant pressures. If the low (LP) or high (HP)

pressures reach a predetermined set point, the refrigeration

system will be shut down.

Range: LP 50 700 kPa

HP 300 3000 kPa

Set points:-

hp fault:- 2800 / 2500 kpa

Lp fault :- 50/350 kpa


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Type: Two double inlet centrifugal blower

wheels with double shafted motor

Quantity: Two (2) per unit

Supply Air: 1350 Litres/second at 470 Paexternal static pressure

Motor:- 2.2 kw @1500rpm , 415 v

Supply fanAs the name applies , itsupplies the conditioned airinside saloon . It draws back70% of return air & 30% of

fresh air & moves past t


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Condenser fan

Type: Multi wing axial fan, 9 blades

Quantity: two (2) per unit

Direction of flow: Draw through

RPM Range: 0 2045 rpm

Motor:- 2.2 KW @1500rpm , 415 v

Its function is draw theatmospheric air throughcondenser coil , inside whichhot refrigerant is flowing ,

thus making the heatrejection & condensing the


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Fresh Air

Damper Motor

Fresh Air Damper

Air dampers

Return Air Damper

Their function is to control the fresh air & return( recirculated) air volume as per requirement.

Mode fresh air return air

damper damper

Vent , partially fully

Cool 1 &2 opened opened

Emergency fully fullyvent opened closed

Smoke fully fully

vent closed Opened


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Electrical cubicle

PLC

CMB, SFB,CFB , DCB ,

EIVCB

CMC, SFC,CFC, ESFC


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Thanks

train air conditioing system

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