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Air Conditioning in Indian Railways-PEE
Citation preview
Electrical Engineering
Rajesh Gupta
Air Conditioning
Prof. Elec. Engg.
Air- Conditioning
IntroductionWhat you will know at the end of session? 1. Organizational Set up & a bit of
history2. Basic concepts in Air-conditioning.3. Capacity and Settings of AC coaches 4. System of Generation 5. Generation in EOG coaches6. How AC works in AC coach7. Development of RMPU 8. LHB coaches & Double Decker AC
train9. Take tour of LHB coach
Introduction
Sr.DEE/Chg
CTA SSE Control
HQ
RBOrganization
DEE/AEE
IntroductionA view at Coaching depot
IntroductionA view at Coaching depot
IntroductionA view at Coaching depot
Sick line of depot
Introduction
HISTORY OF AC COACHES
Air-Conditioning
The first Indian air-conditioned train was Frontier Mail which was introduced in 1934. Earlier, the AC coaches of the train were kept cool by using ice blocks. These were replenished at several halts along the line. A battery operated blower constantly blew air into these receptacles, and the cold air entered the insulated cars through vents.British officers used to travel by Frontier Mail. It was a challenge to maintain the temperature of the AC coaches.
History of AC coaches
Air-Conditioning
The Frontier Mail was one of the first trains in India to get an air conditioned car. The AC car started running from 1934.
History of AC coaches
Air-Conditioning
The North-Western Railway introduced air-conditioned stock in the late 1930's (the earliest was probably the Frontier Mail in 1936 or 1937). In 1952-53 there were air-conditioned services between Bombay and Howrah, Delhi and Madras (Grand Trunk Exp.), Bombay and Delhi, Bombay-Amritsar (Frontier Mail), Bombay-Viramgam (Saurashtra Mail), and Bombay-Ahmedabad (Gujarat Mail).These all used AC units that were mounted beneath the coach body (underslung), interconnected by pipes.
More on history of AC coaches
Air-Conditioning
The first fully air-conditioned train was introduced in 1956 between Howrah and Delhi. Popularly known as the AC Express, it ran on the Grand Chord. Later there were two, one running on the Grand Chord and the other on the Main Line. Another train popularly known as the AC Express was the Dakshin Exp. between Madras and New Delhi in the 1960s.AC Chair Car stock was introduced around 1955. Until about 1979, air-conditioning was available only in these and in AC First Class cars. Around 1979 the first two-tier AC coaches were introduced. The first 3-tier AC coaches were introduced in 1993 (RCF)
More on history of AC coaches
Air-Conditioning
BASIC AIRCONDITIONINGConcept of Human
Comfort
Air-Conditioing
Difference between Air Conditioning & Refrigeration
Factors of Comfort
TemperatureHumidity
Air Flow
Noise
Purity of Air
Air-Conditioning
Air-conditioning – comfort factors• Factors deciding comfort level
• temperature • humidity• draft (velocity of air)• purity of air• Noise
• Humidity – ratio of the moisture contained in a given quantity to the quantity of moisture required to saturate that quantity at a particular temp. It is termed as Relative Humidity (RH).
Air-Conditioning
Unit of Refrigeration
• Unit of Refrigeration – in ton (TR)• It refers to the latent heat required to melt a ton of
ice at 32 degree F in 24 hours• 1 ton = 2000 lbs• Latent heat of Water to freeze -144 BTU/Lb 1 TR = 2000X144 =12000 BTU/Hr
24 = 3000 k Cal/Hr
Air-Conditioning
1TR of Refrigeration capacity?
1 TR Can Cater to Approx.
100 SQFT. (Area)
or 1200 CUFT. (Space)
Air-Conditioning
Relative HumidityAir has capacity to trap moisture. Its capacity to trap moisture varies with temperature.
Temperature 1 Cuf of air 70 deg.F 4 grains 80 deg.F 11 grains 90 deg.F 19 grains
1 kg of water = 15400 grains of moisture
Air-Conditioning
Outside ambient air (say 100 deg. F with 95% RH) is sent over the evaporator at 40 deg. F, moisture is condensed. When this air goes inside the AC compartment it rises to 70 deg. F and as there is now less moisture, the RH becomes 50 % inside.
Method to control RH
Air-Conditioning
Refrigerant• Freon 12 or Freon 22 (Chloro-
difluoromethane) gases
• These are chemical Compounds. Freon is the Trade name. In India the Trade name is Mafron. Manufactured by Navin Fluorine Industries
• To be re planned by non CFC gases by 2012 - to reduce Ozone layer depletion
• R-134 (Tetrafluroethane) a is being used now (Non CFL)
Air-Conditioning
CAPACITY AND SETTINGS OF AC COACHES
Air-Conditioning
Capacity of AC Coaches
As per heat load calculation, Load and Plant capacity of various Coaches
LOAD CAPACITY
• AC II tier 8 TR 2 Plants x 5.3 TR
• AC Ist 5.3 TR 1 Plant x 6.7 TR
• AC Chair Car/III tier 2 Plants x 6.7 TR
Air-Conditioning
Other settings in AC Coach• Fresh air requirement
– Smoking not permitted 0.35 meter cube/min/ passenger
– Smoking permitted 0.7 meter cube/min/
– passenger
• Air Velocity– up to 0.2m/sec inside the compartment– 4 m/sec at the diffuser
Air-Conditioning
Temperature settings in AC Coach
Low MediumHigh
• I AC Cooling 220 C 240 C260 C Heating 170 C 190 C210 C
• II AC Cooling - 240 C 260 CIII AC Heating - 190 C 210 C
Air-Conditioning
SYSTEM OF GENERATIONFOR AC COACHES
Air-Conditioning
Air- Conditioned Coaches
• Air-conditioned Coaches broadly classified as-• Self generating type
• Power for AC equipments is supplied by axle driven alternators at 110V DC
• End on generation type‑• Power from diesel generated sets (DG
sets) at both ends at 750 V AC 3 phase 50 Hz.
• AC equipments operate at 415 V 3 phase 50 Hz. AC
Air-Conditioning
SYSTEM OF GENERATION
IN EOG COACHES
Air-Conditioning
Supply System in End on generation ‑ ‑Coaches• Power supply for air-conditioning, lights and fans is
obtained by tapping from one of the two feeders of 750 V, 3 phase, 50 HZ emanating from the Power Car
• Each coach is provided with 50KVA transformer which steps down voltage to 415 V, 3 phase
• All AC equipments i.e. compressor, condenser, evaporator, heater etc. work on 415V, 3 phase
Air-Conditioning
Supply System in EOG Coachescontd…• For supply to lights and fans, each coach
is provided with a step down transformer of capacity 3 KVA - steps down the voltage from 415 V, 3 phase to 190 V, 3 phase.
•110 V a.c. supply is provided for lamps and fans by connecting them between line and neutral of the secondary side of transformer
Air-Conditioning
Supply System in EOG Coaches contd…A 24 V emergency battery of 90 Ah capacity has been provided on the under frame along with a battery charger. The battery supplies the emergency lights provided in the Coach in the event of a. c. power failure.
Air-Conditioning
Battery Charging at the Terminal Stations For pre cooling , AC Coaches are provided ‑
with
• One 200A capacity battery charger • The battery charger takes 440 V, 3 phase
supply through special battery charging sockets mounted diagonally one on each end wall.
• The battery charger consists of a transformer and a simple diode bridge rectifier.
Air-Conditioning
Refrigeration cycle
Refrigeration cycle – conventional coach
Heating cycle – conventional coach
Air-conditioning system working
Air-Conditioning
Equipments of AC SystemCompressor – compresses & delivers gas into condensers at a high pressure & high temperatureCondenser – it cools the hot gas and liquidates it under pressureExpansion Valve – It controls and regulates the rate of flow of liquid freon under high pressureEvaporator –the cooling unit in which liquid freon under low pressure evaporates & in-doing so takes away the latent heat thereby cooling the medium surrounding the cooling coil
Air-Conditioning
• In conventional type – AC equipments provided on under-frame
• Operates on 110 V DC supply through 18/25 KW alternators
• Thermostat senses the inside temperature of the coach
• Battery charger is provided on under-frame for charging the batteries
• Pre-cooling sockets are provided on either side of the coach for pre-cooling purpose
AC system in conventional type Coaches
Air-Conditioning
Under slung Type AC System
Air-Conditioning
BRUSH LESS ALTERNATOR
Air-Conditioning
Refrigerant gas leakage from pipes and jointsHeavy weight - coach tare weight increasesLarge space occupation by the equipmentsMaintenance problems - Huge skilled manpower required Consumes more power - Less energy efficientUnder-slung equipments get hit by ballast, CROAccumulated dust affects heat transfer
Drawbacks of Conventional AC system
Air-Conditioning
Development of RMPU• Reliable static Inverters (for
conversion of 110 volt dc into 3-phase ac)
• Use of 3- phase brushless compact motors possible.
• Development of Package Units for Rolling Stock applications
• Disadvantages of Opentype (underslung) eliminated.
• Weight advantage - one Ton against three Tons)
Air-Conditioning
RMPU of 5.2 introduced in the year 1992 with 25 KW alternator
• AC II tier & AC III tier - Two units of 7.0 TR
• First AC - one unit of 7 TR
• Mounted above the toilets on both ends supplying conditioned air in the tapered duct to serve the coach end to end
Roof-Mounted Packaged Unit (RMPU)
Air-Conditioning
Roof-Mounted Packaged Unit (RMPU)Top view
Air-Conditioning
LOOK ONTO THE COMPRESSORS
Air-ConditioningComparison of RMPU with Conventional under-frame AC system
RMPU Conventional AC
Weight 900 Kgs (2 units)
2700 kgs
Installation time
4 hrs 4 days
Refrigerant R – 134a R – 12
Refrigerant charge
2.85 Kgs 15 Kgs
Danger due to cattle run over / flood
Nil Heavy
Down time for repairs
4 hrs. Very long time
Air-Conditioning
Linke Hoffman Bosch (LHB) coaches
• State of the art coaches Rajdhani / Shatabdi Exp. Trains Modern passenger amenities
• Technology transfer M/s Alstom – LHB of Germany
• Manufactured at RCF, Kapurthala From the year 2003
Air-ConditioningLHB Coaches
Aesthetically superior Interiors
Very low noise
Fire retardant materials
Modular toilets with controlled discharge
Light weight
Air-Conditioning
GENERAL FEATURES OF LHB COACH
IV COUPLER
EXT. SUPPLY SOCKET
BATTERIES BATTERY FUSE BOX
AC PACKAGE UNIT FRESH AIR INTAKE
EXHAUSTFAN
Air-Conditioning
Basic Components of LHB Coach
Air-Conditioning
Basic Components of LHB Coach
Air-Conditioning
Basic Components of LHB Coach
Air-Conditioning
Basic Components of LHB Coach