Most reefers run on deisal or gasoline a good way for shippers to save cash and the air.When you add up a 100 cars and the gas they use thats a lot of money.
The fuel cost savings are there - But how far can you run on a tank of NG? Also, you will need fueling stations for all of this. BNSF test ran LNG engines years ago and had a massive insulated tank car to carry the ‘fuel’.
Anyone know what the typical refrigeration unit consumes on NG per hour. I suspect it may need a rather large fuel tank to keep it powered for days on end…
Jim
I know Kroger has a few LNG powered reefer units they are trying on a Test basis. They are Restricted to a max range from the DC of 4 Hours hauling anything that needs to be held below Zero. 7 Hours if only holding Fresh Products. Compare that to a Diesel Engine powered one that with 50 Gallons of fuel they last for 2 days on that amount.
Bonas,
Are you talking about an absorption refrigeration unit or simply using natural gas to fuel an engine to run a compressor?
John
Natural gas to fuel an engine to run a compressor. Sounds like the old Survel refrigerator.
You are right, Wayne. But today there are modern absorption refrigerators being made with freezers above them. They are more expensive than conventional types but are used in places with no electricity.
Absorption cooling units have no moving parts so they are quite robust. It is a simple technology. It does require a source of heat but any kind of fuel could be used. You can even buy a refrigerator that burns kerosene. However, I have never heard of one that burns coal.
John
https://www.thenaturalhome.com/gasappliances.htm
I gotta get me one of these
Now I am thinking of UPs Train X The Produce Express from Walla Walla to Upstate NY. You could have a fuel tender and hook ups. WAIT A MINUTE! The SUSYQ has a Intermodal Reefer train that has a Dieasl Generator Container that powered 6 other Reefer Containers.
So how much natural gas can a reefer carry before it needs a placard?
I thought I had an answer to a question, but upon further research it turned out I did not so I deleted the original content.
I assume you have seen the price, Bonas. These boxes are not cheap. If you live in the east you can get one from “Lehmans,” an on line hardware store that deals with Amish farmers. And you can get one that uses butane, natural gas or kerosene as well as propane. I suggest you also get the vent kit as having an unvented flame inside your house is not a good idea.
John
That’s interesting Bonas, I didn’t know Servels were made anymore. I know they were pretty popular with US forces in Vietnam all those years ago.
Not cheap, but I suppose if you live in the “boonies” and you lose electric power every time a squirrel “poops” on a line they’re a pretty good investment.
Setting up multiple reefers on a train to receive power for their refrigeration units from a central generator has been done for decades. The generator could well be fueled by natrual gas instead of diesel. NG generatrors are currently commercially available:
http://www.cat.com/power-generation/generator-sets/gas-generator-sets
One problem with such arrangements is that railcars do go bad order and have to be set out for repair. When that happens you have no power and the load gets spoiled. If you set out the entire group that is connected to the generator, in order to maintain the power supply, multiple shipments get delayed.
So, you could be looking at something like one generator on one three well stack car providing power to five containers. The sixth container position would be taken by a “container” with the generator and fuel.
You’d loose 1/6th of your capacity. How this trades off economically against a generator on each container will determine the success or failure of such a system.
For the drayage portions of the movement you’d need to attach a clip on generator to the containers.
When I was a kid we had Servel gas refrigerators in my house. And the one thing I recall most is the periodic requirement to defrost them, to get the slabs of ice off the “continuous cool” evaporator sheets.
You’d have to switch the mechanism into “defrost” mode, and then have a dripping mess inside the box for 1-2 hours while things thawed out. All the while you had to have a plan “b” for your delicate goods.
All refrigerators need to be defrosted from time to time. Conventional refrigerators have an automatic defrost cycle. The refrigerator cycles off, frost melts and water drops to a tray where he is led down a tube to a shallow pan and evaporates. I don’t know if absorption refrigerators have an automatic defrost cycle as I have no experience with them since the 1940’s.
Trouble is, you start setting up unattended off cycles in an absorbtion machine, you run a risk the machine will solidify. If that happens, write the cargo off.
When you introduced this thread I did not know if you meant that natural gas could be used to power an electric generator for a compressor motor or if you meant that natural gas could be used to provide the heat adsorption refrigeration requires. I don’t really intend to argue that adsorption refrigeration should be used in railroad refrigerator cars. So I accept your assessment as far as railroads are concerned.
A 20KW NG powered genset will require almost 300 cuft/hr of CNG at full load. At 1/4 load, it’s about half that.
A 250 Cu Ft tank at 3000 lbs could theoretically last over 150 hours at the full load figure.
Lots of variables to play with there, though. Tank size, pressure, fuel usage by the motor, etc.
I can not say about refrigeration units run on natural gas only diesel. Ambient temperatures combined with load requirements make a huge difference in fuel consumption. Produce loads in very hot temperatures(above 100f)being one of the worst. Close on that is ice cream in high temperatures (above 90f). The next category on fuel consumption hot cargoes (maintain +80f or higher) in sub zero ambient(outside air -1f or colder). The first and second are about the worst because of the potential of overheating the refrigerant. And the potential of over pressure of the refrigerant in the unit. Also fresh produce either hard or soft the unit has to run continuously to keep the air flowing, My opinion on refrigeration by rail: Have the unit itself run on electricity and have an external source to power the unit. This way you can pick and chose your fuel source. LNG, diesel or shore power. This is how ocean ships work. Generally most ocean going container voyages have a dozen or more temperature controlled cargoes. And the ship provides the power to run the units at sea. Rgds IGN
Alaska Railroad uses HEP on their SD70MACs to keep intermodal containers warm during the winter. I don’t see why refrigeration units wouldn’t work the same way, until max capacity of the locomotive was reached.
CN has air repeater cars that have an air compressor for cold weather, a larger engine in one could also provide HEP.
http://www.railpictures.net/viewphoto.php?id=424763&nseq=109&favsearch=1
Thank you for your input. It’s always good to hear from someone who knows what they are talking about.
There are a whole lot of ways to do this. Each way has its own advantages and disadvantages. It may be that rail refrigerated intermodal moves best in trailers, not containers. I’ve heard tell that new Wabash Arctic Lite reefer trailers can possibly carry 50,000 pounds of payload. The best an intermodal reefer container can do is 43,500. (Highway weight restrictions) That’s a big payload penalty. It may be best to just put the light weight trailers on articulated spine cars.
But I do agree that while on the rail the power for refrigeration should come from a centralized source, maybe one generator per car. With multiple spine/well cars in a train