Air Conditioning in Rail Coaches

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KP Member Join Date: Jan 2009 Posts: 6	Air Conditioning in Rail Coaches 01/15/2009 8:05 AM
	For Air Conditioning in Rail Coaches there are individual Air conditioners powered by Battery fitted in each coach. Why we can not have Centralised Air Conditioner with Air duct running for all Coaches ? Also, we can have Vapour Absorption Chillers using the Exhaust Gas of Diesel Locomotives. Any such Systems are already in use ?
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#5 "Re: Air Conditioning in Rail Coaches" by elnav on 01/16/2009 3:03 AM (score 2)

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#6 "Re: Air Conditioning in Rail Coaches" by Chankley on 01/16/2009 4:48 AM (score 1)
#7 "Re: Air Conditioning in Rail Coaches" by rrnut-2 on 01/16/2009 8:29 AM (score 1)
#8 "Re: Air Conditioning in Rail Coaches" by Ried on 01/16/2009 9:27 AM (score 1)

Hendrik Guru Join Date: Jan 2007 Location: Centurion, South Africa Posts: 3921 Good Answers: 97	#1 Re: Air Conditioning in Rail Coaches 01/15/2009 11:12 AM
	You would need a big flexible / insulated joint between the coaches. The cooling effect will change over time unless the diesels run at a constant speed. __________________ Never do today what you can put of until tomorrow - Student motto
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ozzb Guru Join Date: Mar 2007 Location: Rosedale, Maryland USA Posts: 5197 Good Answers: 266	#2 Re: Air Conditioning in Rail Coaches 01/15/2009 1:10 PM
	Rail cars are made to be connected and disconnected as the need arises. The individual AC units on the coaches aids this. If you used a centralized system it would have to be designed with the train as a whole. Limiting the placement of the cars or their replacements. __________________ Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
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Anonymous Poster	#3 Re: Air Conditioning in Rail Coaches 01/15/2009 11:27 PM
	Air Coaches today are manufactured in such a way that it can be fitted or attached to any trains anytime. In case u have a centralised AC system the whole trains needs to be AC. All over world only few cases are there where trains are fully AC. So its convinient Think @ the losses in duct. Leakages if any crack goes into flexible joint. time required to cool the whole train and keeping all coaches at same temp. difficult
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KP Member Join Date: Jan 2009 Posts: 6	#4 In reply to #3 Re: Air Conditioning in Rail Coaches 01/16/2009 1:34 AM
	Nowadays more and more Trains are run with all Coaches Airconditioned. Also, these Coaches are run as a single Rack. They are seldom detached and run in other trains. Hence, we can think of Centralised Airconditioning in such Trains. This has several advantages like : 1. Investment saving [ Elimination of Large Bateries, Charging Generators, Several small AC Systems (as against a few large ones), Individual Control panels for each Coach, etc) 2. Operating Cost saving [ Elimination of Energy loss by Belt Driven Genrators / Charging of Bateries / Energy loss in Battery, Additional Fuel requirement for carrying huge Batteries / Generators in each Coach, Idle running of Generators when the batteries are charged Full, etc]. As for the Cooling Loss / Leakages associated with Cool Air Ducts, we can have Chilled Water Piping running between Coaches. Fin-Fan Coolers with this Chilled Water can be installed in the Coaches. I would like to have feed back on the Vapour Absorption Chiller based on the Exhuast from Diesel Engine. There are several Diesel Engine based Power Plants where Vapour Absorption Chillers have been installed using the Exhaust Gas / Cooling Water. A similar system can be thought of for Train Engines also. K.Periasamy
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elnav Guru Join Date: Dec 2006 Location: Western Canada Posts: 1863 Good Answers: 39	#5 In reply to #4 Re: Air Conditioning in Rail Coaches 01/16/2009 3:03 AM
	Nowadays more and more Trains are run with all Coaches Airconditioned. Also, these Coaches are run as a single Rack. They are seldom detached and run in other trains. REPLY Maybe in your part of the world. And what happens when passenger trains have to change engines as they cross borders or juristictions? Trust a cost accountant to try and screw things up that aint broke. In one big central system what happens when that one cental chiller breaks down? As for savings what you may save one way you wil lose by much more in other ways. Power usually comes from Head end. Battery is only for support during shunting and change outs. "Idle running of Generators when the batteries are charged Full, etc]." Haven't you ever head of smart chargers that shut themselves OFF when battery is full? __________________ Elnav
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Join Date: Jan 2009

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#11
In reply to #5

Re: Air Conditioning in Rail Coaches

01/17/2009 6:31 AM

Thank you all for the feed back.

Yes in India, China, Brazil, Russia, etc majority population still travel by Train and this trend will continue, and shall continue - since we can not afford to use Road / Air extensively, which consume lot of Fuel. We rely on imported Petroleum and the Fuel consumption in Road is about 6 times as that of Train. For Air travel it is much higher( Can someone give the Number ?).

We can always have Three Absorption Chillers (for about 20 coaches) with Two running and one as Standby. The Chillers can be fitted in a separate Coach next to the Engine with the Exhaust Gas from the Engine being ducted to this Coach. Chilled water line can be run from this Coach to other Coaches( like the Vacuum Brake Hose).

Kindly note, in India / China / Brazil, all the Coaches in a Train are run as a Rack without any detachment / attachment in any Province / Jurisdiction. Even during maintenance, all the Coaches of each Train are maintained simultaneously. Hence, the attachment / detachment of Chilled Water Hose is not an issue.

When the Engine is not in Full power, like in idling, we can supplement the Vapour absorption chillers with Direct Firing of Diesel. Please note, when the Engine is idling( which means the Train is stationary), the cooling requirement is also less.

Please note, presently the Air Conditioning is by the Compressor based AC systems which are driven by Batteries continuously charged by Generators (which in turn are belt driven from the Coach wheel). Even if the Main Power is coming from the Engine( which I am not sure - I will check and come back), the ultimate source of energy is the Diesel Engine BHP.

In Vapour absorption chiller concept, we will be using only the Waste Heat from the Engine and not the Engine BHP.

As for the Generator idling, I would like to add that even if the Battery is shut when the charge is full, the Generator will be running idle since it is Belt driven from the Coach wheel. Even for idle running there is energy requirement, which is about 10-15 % of the full power.

The initial capital cost of Vapour absorption chillers will be substantially cheaper if you add the Cost of Individual ACs, Batteries, Generators, Control panels. The Operating and Maintenance cost will be very much lower for the Vapour absorption Chiller option.

Can someone working in Chinese / Indian Railways throw some light on this subject ?

K.Periasamy

KP Member Join Date: Jan 2009 Posts: 6	#12 In reply to #11 Re: Air Conditioning in Rail Coaches 01/17/2009 10:50 AM
	In India, majority of the Coaches are Self Generating only. The Power is not cabled from the Engine. Please see the Link given below. http://www.assocham.org/events/recent/event_245/Sameer_S_Gosavi.pdf Unfortunately, the improvement proposed in the above Link (One Diesel Generating Set for each Coach) is also not upto the mark ! In my opinion, it is not a right solution. K.Periasamy
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Chankley Power-User Join Date: Sep 2007 Location: South coast of England Posts: 411 Good Answers: 36	#6 Re: Air Conditioning in Rail Coaches 01/16/2009 4:48 AM
	The weight must be distributed evenly in a train which is why many have distributed power. A centralised AC unit would leave one car heavier than the rest. The size of the ducts would be another issue as the space under a train is very limited due to all the systems mounted underneath. Threading the ducts through the bogies (trucks) with all the brake gear, motors, retention toilet tanks etc. would be almost impossible.
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rrnut-2 Power-User Join Date: Jan 2008 Location: New Hampshire Posts: 106 Good Answers: 3	#7 Re: Air Conditioning in Rail Coaches 01/16/2009 8:29 AM
	On Amtrak, the Head End power supplies 480vac for the AC and Heat. The batteries are for the lights during engines changes, if that particular car has batteries. Most batteries are gone, maintenance headache. __________________ rrnut-2
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Ried Guru Join Date: Dec 2005 Posts: 1602 Good Answers: 19	#8 Re: Air Conditioning in Rail Coaches 01/16/2009 9:27 AM
	Along with the other good answers, decentralized car AC allows more flexibility with maintenance. If AC on one car goes out, only one car needs to be out of service, and repair to a small AC is usually less expensive and quicker to perform. An AC outage on a centralized system takes the whole train out of service, and repair will generally be more expensive and take longer. __________________ Eventually, one needs to realize that it is far less important to be the smartest person in the room than it is to sit next to that person and make friends.
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gideon Power-User Join Date: Jan 2007 Location: Johannesburg, South Africa Posts: 230 Good Answers: 16	#9 In reply to #8 Re: Air Conditioning in Rail Coaches 01/16/2009 2:35 PM
	Also, in some countries coaches gets turned around, so a universal fitting (not male-female) is required. Remember, ease of maintenance becomes paramount once the coaches are in service. I suspect that ducting would also experience numerous problems with vibrations. Chilled water might be easier if you want to use it. Sorry, I have no experience of the vapour-type unit you mention, I'm not an AC expert, just have some railway knowledge. Everything fitted to rail rolling stock needs to be extremely rugged!
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Rorschach Guru Join Date: Jan 2008 Location: Spring, Texas Posts: 3403 Good Answers: 150	#10 Re: Air Conditioning in Rail Coaches 01/16/2009 4:59 PM
	Who rides trains anymore? All passenger service in the US (such as it is) is heavily subsidized by the US Government. Nobody can honestly explain why either. __________________ Who is John Galt?
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rrnut-2 Power-User Join Date: Jan 2008 Location: New Hampshire Posts: 106 Good Answers: 3	#14 In reply to #10 Re: Air Conditioning in Rail Coaches 01/19/2009 7:04 AM
	No different than any other country with passenger rail. We are the only ones that thing passenger rail should pay for itself. By the way, US airlines are subsidized by the government too. __________________ rrnut-2
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ckartson Commentator Join Date: Mar 2008 Location: Strongsville, Ohio USA Posts: 62	#13 Re: Air Conditioning in Rail Coaches 01/18/2009 9:58 PM
	I think sizing the central plant would be nearly immpossible. The equipment would need to operate with a load of only a few cars or operate with many cars. each car having its own hvac system allows the load to be spread evenly as needed.
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