All the comments about what's needed to make an ammonia absorption cycle refrigerator work, emphasizes why Carrier went with the steam ejector for steam powered A/C.
The steam ejector was one of the first applications of supersonic nozzles and diffusers. The supersonic flow was needed to make sure the steam from the nozzles didn't flow back into the chamber being evacuated. This was followed by a diffuser to slow down the steam and thus increasing pressure - a KEY POINT as it allowed condensation at a higher temperature than the water being evaporated for cooling.
From what I understand, steam ejectors are still being used to make condensed milk.
We had a RV with a propane-fired fridge when I was growing up. It had to be pretty much absolutely level to work, Dad would shut it off before driving and level the RV with jacks before turning it back on.
Steam heat and electric lighting in railcars were massive improvements over the previous systems. Doesn't coal stoves and gas lighting inside a wood car sound like a great combination in crashes!?
VIA Rail did not finish phasing out steam heated equipment until 1997, and for much of the transition period the new LRC and F40 locomotives could be seen paired with a steam generator car or trailing F-units of both EMD and MLW varieties.
Greetings from Alberta
-an Articulate Malcontent
An attempt to explain the adsorption cycle is to think of a coffee percolator. The heat boils water and the steam pushes the water up the pipe to let it fall down through the grounds. In the refrigerator, the water mixes with the ammonia and then is heated. the heated water/ammonia moves like a percolator to a tank where the ammonia is de-adsorbed (becomes a gas) and then flows through the condensor where it cools and liquifies. Meanwhile the water returns back to the adsorbtion tank. The ammonia (now a) liquid flows through the evaporator where it returns to a gas absorbing heat from the area to be cooled and then flows back to the adsorbor where the water and ammonia mix again. Similar to the freon cycle, boiling and condensing.
When I was very young, we lived in Milwaukee and had a Servel Refrigerator. If I recall it was not very good at making ice cubes but then, we were not drinking cold drinks very much back then. In '43, we moved to Greenhills, OH where we did not have natual gas and I don't know what dad did with it. The row house we lived in had a coal fired steam heat. No electricity used. No thermostat. Open dampers or shut them to control heat. In the fifties, after dad bought the unit, he converted to oil.
When I got a camping trailer in the '80's I got a Dometic refrigerator that operated on 12 V dc, 120V ac, or propane. It operates on an adsorption cycle.
Now for RR's the PRR's E units had two steam generators, and two prime movers. PRR I presume wanted redundacy for reliabilty. A primay mfg of the steam heating was VAPOR. And the sleepers had individual thermostats and steam valves for each room, plus the other areas.
Back when the CB&Q first went to to bilevel commuter cars, they had steam heat but used a generator installed in a single level coach baggage car for lights and AC. They didn't operate push-pull but had to turn the engine at each end of the run. After seeing how well PP worked on the C&NW, they went to HEP. Took the steam generators out and installed small HEP diesel generators.
And one more thing, the Burlington's early Zephers had HEP generators for their AC, lights & heat. The Illinois Railroad Museum's Nebraska Zepher still runs and a number of years ago ('81) took it out on the BNSF from Chicago to Quincy IL and back. It passed ALL inspections FRA, UP, BNSF, AMTRAK and itoperated at BNSF track speed, 79mph. The IRM crew even served meals cooked on the train. To me, that is an amazing feat.
Forgive the fans exuberance.
https://www.youtube.com/watch?v=ByfGKEBQcwQ
54light15I was at a seminar on absorption chillers. My mind was boggled, I just could not grasp the concept and I still can't. My boss asked me what I learned. I said, "They work by magic!" He laughed but I still had no comprehension of them so it might as well be magic. It was too much and it made my brain sting.
A number of years ago I had a Mini-motorhome. It used LPG for heating with a ordinary furnace as well as cooling the refrigerator by being the heat source for the amonia -compression - expansion - compression cooling cycle. The principles of cooling remain the same, no matter of amonia, freon or some other similar material is used. The air conditioner for the motorhome was run by 120v AC, which also supplied the heating element for the refrigerator when electricity was available.
Never too old to have a happy childhood!
We had at least one thread on steam ejector air conditioning in which Erik provided a couple of really good detail drawings showing how things worked on a modern car. High pressure steam is allowed to flow fast enough to augment the pulling of a vacuum with shockwaves; water boils at the low ejector pressure and carries away the usual enormous latent heat of vaporization characteristic of water...
http://cs.trains.com/trn/f/111/p/260457/2928188.aspx
All you need to know about ammonia absorption refrigeration is that ammonia boils at a low temperature -- it was and is an excellent refrigerant for that reason -- and is also hellishly absorbed in cool water, but readily separated by heating that water. Read the operating principle of the IcyBall and the specific method to manually 'regenerate' and then re-start it for a straightforward account of a simple ammonia setup.
I was at a seminar on absorption chillers. My mind was boggled, I just could not grasp the concept and I still can't. My boss asked me what I learned. I said, "They work by magic!" He laughed but I still had no comprehension of them so it might as well be magic. It was too much and it made my brain sting.
Servel is a well-known brand of absorption refrigerator -- it used a similar cycle to the Electrolux Dometic: ammonia, water, and hydrogen, with no moving parts.
http://vintageservelrefrigerators.com/HowItWorks.html
Einstein and Szilárd, of later atomic device fame, patented a version employing butane instead of hydrogen.
You can make an air conditioner on this principle with little more than humid air, water and brine -- using heat to concentrate the brine.
For true weirdness look up the IcyBall refrigerator, another ammonia absorption type, which Crosley made famous.
tdmidgetServel it was indeed and similar units are in some RVs today. But I don't know how they worked.
It had to involve a evaporator of some kind, evaporate water and you get cool air the faster you evaporate the cooler the air is that is produced. I remember an experiment where with just some alchol we produced Ice in meterology course via rapid fanning with a theme book......rapid evaporation of a liquid.
Also, for the OP's benefit, the steam was under pressure and they had thick pipes under the cars to carry it I think they were at least 2 inches across if not more. The joint between cars i think was screwed on (don't remember) and I think they could shut off the steam under pressure while they made the connection between cars similar to the air brakes.
gregruddDid the Fish belly Keystone Cars use Head End Power with off the shelf industrial equipment.
Andrew WillieA very interesting question, especially about cars that were heated by steam
Amtrak's adoption of Head End Power (HEP) for electrical heating and cooling has eliminated steam for heating and cooling on cars allowed to operate on Amtrak trains (both Amtrak cars and Amtrak authorized Private Cars).
A very interesting question, especially about cars that were heated by steam
Not only did you have to have steam escaping from the rear of train also had to have valve cracked on head end of lead engine.
We used to figure 10 lbs steam pressure per car was about the proper amount on the Rock Island. Winter was the real challenge. As soon as the train got moving and snow started swirling under the cars it really cooled off the steam pipes. You'd be sitting at a station stop with 160 lbs of steam pressure on a 10 car train and would be lucky to have 60lbs when you reached 79mph.
In NSW Australia we used what were known as Mclaren foot warmers which had a chemical inside which when taken out of boiling water or a stove would hold its heat for a number of hours. When the RUB/HUB air-conditioned cars were introduced in the 1940's these used Head End Power from day one with power vans on each train which provided 415V 3-phase 50 hz (Australian Standard industrial frequency) to run both the Air Conditioning and the Buffet/Dining cars. It is not a wide known fact that the then NSWGR were one of the first users of industrial frequency head end power in the world. Thus reducing both capital and maintainence costs over the long term as standard industrial equipment was used. It was found in NSW that the other systems around at the time namely 32v/110v powered by either axle mounted generators/steam turbo generators were both inefficent and more costly to purchase /maintain compared to freon based systems running on industrial frequency with head end power.
Now to bring a US focus back to the post. Did the Fish belly Keystone Cars use Head End Power with off the shelf industrial equipment. As in White's book he makes mention of power vans being used but I don't know wether these used industrial voltage and frequency equipment. Which in the US would be 220V 3 phase 60hz
The three biggest user of steam ejector AC were ATSF, NYC and Milw.
On of the worst US RR accidents of the 19th Century (maybe ever) was when a bridge on the LS&MS collapsed under a train in the winter and the coal stoves ignited the wooden cars. Doesn't bear thinking about!
It was steam, right up to the Amtrak era -- and even somewhat into, as it took awhile for cars to be converted to electric (head end power) heat.
Yep, very good! Amtrak slowly converted sets of Heritage Fleet cars to HEP ( Head End Power). The last trains long distance trains to be converted were on the east coast in 1981. Sad for me, slightly, because that's when the last SDP40fs went "bye-bye" on the Silver Service trains. The F40 was virtually Amtrak's mascot.
Amtrak's Beech Grove shop crews did an excellent job and those HEP Heritage cars were such a joy to ride in. Upset me when Amtrak was forced to retire most of them because of the toilet isse.
"I like my Pullman Standards & Budds in Stainless Steel flavors, thank you!"
Before steam heated passenger cars, cars were heated by coal stoves. If you were near the stove you were too hot and and if you were not, you froze. It is also my understanding that those stoves started lots of fires when wooden passenger cars derailed. Steam heat was a great step forward.
dd
In Japan the transition was from steam to catenary, and the catenary motors did not have train heat boilers. The solution was to mount the boiler of an obsolete locomotive in something resembling a baggage car with a coal bunker at one end to provide steam.
The down side was, many of the lines where these things ran had tunnels - often long ones. With no exhaust to provide draft, the coalburners produced copious quantities of black smoke. They also smelled pretty terrible. I can imagine the reaction of someone who wants to ban smoking everywhere, if faced with one of these!
In spite of that, I'm still going to have to model one (or more) for use on my older passenger trains. After the equinox, it gets pretty cold in the Central Japan Alps.
Chuck (modeling Central Japan in September, 1964)
Modelcar wrote:....Using steam to "cool" cars is not much more unusual than using natural gas to "cool" via the mechanism in certain refrigerators. Such coolers were produced and in use in homes back in the 30's. Believe they featured practically no moving parts. Trying to remember the manufacturers name.....Was it Servel....
....Using steam to "cool" cars is not much more unusual than using natural gas to "cool" via the mechanism in certain refrigerators. Such coolers were produced and in use in homes back in the 30's. Believe they featured practically no moving parts. Trying to remember the manufacturers name.....Was it Servel....
The Servel refrigerators used an ammonia absorption cycle - the heat was used to separate the ammonia from the water. This cycle is very sensitive to the fridge being tilted and probably would not work well on a RR passenger car.
Steam cooling on passenger cars was doen by the steam ejector method - the steam was used to create a vacuum which then would cause the water to boil at low temperatures. The cooled water would then be circulated through a heat exchanger to cool the air. Problems with this system were a high use of steam (more than for heating) and the air couldn't be cooled as much as with a freon cycle.
Hey, and let's not forget this important detail with steam heated trains: the trailing steam pipe valve on the trailing car always was cracked open just a wee bit. By doing so, this allows of continuous flow of fresh steam from the locomotive to the last car and all of the equipment in between, and it also serves as the point where any condensation could be discharged.
In addition to passenger coaches, diners, sleepers, lounge, and observation cars, the head end equipment such as baggage, mail storage, and Railway Post Office cars also had steam pipes and radiators. Certain piggyback flats and Flexi-Van flats built for passenger service had well insulated pass-through steam pipes as well.
On December 22, 1971, I caught the combined Super Chief / El Capitan at Barstow, Calif. for a ride to Chicago. The weather east of California got pretty cold in spots so the Santa Fe tacked-on a baggage car equipped with two Vapor brand steam generators to the rear of the train. I was riding in a bedroom of the last sleeper and was toasty warm throughout the trip.
gn goat wrote:1. Was steam piped back from the locomotive to heat the cars? And if so, wouldn't the steam cool in a longer consist?
1. Was steam piped back from the locomotive to heat the cars? And if so, wouldn't the steam cool in a longer consist?
Yes to the first part and a qualified yes to the second part. The problem was as much steam leaks as it was steam cooling. The drop in steam temperature and pressure wasn't as bad as it might seem since the steam pressure was dropped to slightly over atmospheric before it went into the heating coils.
2. In the steam era how were passenger cars heated?
John H. White, Jr's The American Railroad Passenger Car does a good job of explaining how the steam heat system came to be and what it replaced. It is a good all-around source on passenger car design, construction and auxiliaries from 1830 to about 1970.
Instead of a steam generator, the steam came directly from the locomotive boiler, one of the distinguishing characteristics of a passenger locomotove was a steam connection (some frieght engines were so equiped to allow use on passenger trains). The steam generators on diesel locomotives were added for backwards comatibility.
The earliest diesel trains often used heat from the engine for train heat - but experience dictated that a steam generator be added. The Butte, Anaconda and Pacific used electric heating after the line was electrified in 1913.
....Trying to remember the heating system in PRR cars....Believe the steam piping was at the corner of the floor and the side wall....enclosed in a lovered incasement of sort. Radiating heat out from it.
Quentin
It was steam, right up to the Amtrak era -- and even somewhat into, as it took awhile for cars to be converted to electric (head end power) heat. Depending on the train, and the equipment, and the maintenance of the equipment, steam heat could be very good or very bad, and it didn't necessarily get worse the farther back you went. Without getting into a dissertation on how steam heat works, suffice it to say that if the steam generator or the engine had enough capacity, the heat came from 'radiators' in each car (there were a variety of different schemes, depending on the kind of car), and each car's temperature was independently controlled in the car. Maintenance was a big issue -- not only was there the problem of steam leaks (particularly where the hoses coupled) but there were the traps and valves on each car which had to work properly.
The steam generators on diesels were, fundamentally, boilers not unlike the ones in a steam heated house of the era. They worked pretty well, most of the time... but they could, and sometimes did, have firing problems which could result in plentiful black smoke or even explosions in the fire box -- which rarely damaged anything beyond the boiler, but could really shake up the engineer and fireman!
Interestingly, on some services steam was also used to cool the cars -- which also worked well, although it seems weird to use steam (hot) to produce cooling!
The PRR cars I rode according to the engineers I spoke to used steam pumped into
radiators that were mounted on the bottom of each side of the cars
gn goat wrote: I know that EMD "F" units were extended 4 feet to accommodate a steam generator for passenger service. Here are my questions:1. Was steam piped back from the locomotive to heat the cars? And if so, wouldn't the steam cool in a longer consist?2. In the steam era how were passenger cars heated? the goat
I know that EMD "F" units were extended 4 feet to accommodate a steam generator for passenger service. Here are my questions:
the goat
Living nearby to MP 186 of the UPRR Austin TX Sub
......My memory tells me it was steam. Depending how it was regulated...{controlled}, they were either pretty warm to not warm or sometimes pretty comfortable. That's my memory of a bit of travel in that era....Don't know how the steam was controlled to regulate the "right" heat in the car.
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