Wind socks

Trains Magazine General Discussion
1

In a post sometime back, there was info about windsocks in railroad yards. I understood they were there in case of a tank car rupture. Emergancy personel need to know which way a potential cloud woould be moving.

Today, I noticed one in my town, not at the railyard. There is a freezer warehouse that always has 3 or 4 reefers at the doors. They ship out boxed, frozen pork, and apparantly ship in some frozen foods like pizza. At the end of the spur, next to the building and the grade crossing is a big ol’ wind sock. What would be the need for one there?

2

I suspect that the coolant being used to control the temperature in a building of that size might present some toxicity or suffocation hazards if it were to escape.

3

Refrigeration units of the size needed to cool large cold storage warehouses use ammonia as a refrigerant, which is not a good thing to inhale. Those chillers use a lot of refrigerant…

4

I work a block away from the Washington DC main post office where two people died from anthrax poisoning a few years back. The huge building was shut down for the better part of two years, the work force was scattered, but the windsock remains in the trailer lot. I pass it everyday on my stroll to the Metro.

RIX

5

Amonia? I thought most all refridgerator equipment used freon? Is that just small, residential & automotive equipment that uses freon?

6

Actually, several different compounds can be used as refrigerant, Freon is actually R12, there is R134a, R22, and several other approved refrigerants. I was even told that Propane can be used, but not recommended (for explosive reasons). It has been a long time since I took a refrigeration class, should really go back for a refresher one of these days…

7

Yes, small units, because freon is not a toxic inhalation hazard. Ammonia is a much better refrigerant, and cheaper too. But generally it’s only used in industrial applications where people can be trained on self-contained breathing apparatus and that safety equipment supplied.

RWM

RWM

8

I think a lot of ice rinks use ammonia as well.

9

I seem to recall that Freon was considered a wonder refrigerant as it was almost as good as ammonia, but way less toxic. My recollection was that the difference was a few percent in efficiency.

One other advantage of ammonia is that it occurs in nature, and I would be very surprised if it didn’t break down faster than Freon. The chief problem with the older Freon’s is that the molecule would typically break down in the ozone layer and the freed chlorine atom could break down many ozone molecules before being combing with something else.

10

…Automotive Freon has been changed to another number in the last 10 years or so…It’s not Freon 12 anymore.

11

A wind sock could indicate a helicopter landing area.

12

Ammonia is typically used to chill large structures such as are found in the meatpacking and cold storage industries. The windsocks are there due to the inhalation hazzard. However there is an additional hazzard – explosion. I’m sure that somewhere on the web you could find pictures of buildings with a side blown out, as I recall that happened at a Sioux City warehouse perhaps 10 years ago.

Recently train crews in the Midwest were cautioned to take care when switching near ammonia fertilizer tanks, in particular at night. Ammonia is one of the ingredients used to make meth, and we have more than our share of cookers. It seems that sometimes the tanks were raided for an ammonia supply, and the thieves were less than careful about shutting everything off when they were finished.

13

WIND SOCK = Preamble to “Nikes don’t fail me now!”

14

A CP guy I talked with in Hastings, MN said the wind sock on the shed next to the old MILW depot was in-case the section foreman farted.

15

I used to work in a chlorine plant and you were forbidden to enter if you didn’t know the wind direction. Most uninformed people get it wrong also. In the event of a leak you grab the biggest lung full of air you can and head upwind as fast as you can. Eventually you will come out of it. If you head downwind you never get free of the stuff.

16

A second use of a Wind Sock at a Hump yard is to ‘fine tune’ the retarders depending where the wind is coming from…if cars are humped ‘into the wind’ the wind will provide a retardation force of it’s own in addition to that of the retarders and if the retarders provide too much retardation the cars might not roll into the clear on their designated tracks. Or if the wind follows the car over the hump it will have more speed than normal and will need additional retardation to make a safe speed coupling in it’s designated track.

17

The wind sock is a requirement by OSHA for any facility that stores or uses any hazardous material that can be or is a gas, or may form a vapor cloud if released to atmosphere.

Your freezer plant qualifies in this regard.

Freon is not very efficient for large volume freezing…Ammonia is.

To achieve the same efficiency as ammonia, you would have to compress the Freon upwards of 1/3 more than what your home freezer does, and have an expensive adjustable expansion valve in your heat exchanger.

Ammonia does the same job on a larger volume cheaper.

The main reason Freon is used in your refrigerator is safety.

Your freezer uses Freon compressed to a high pressure and is then used in a relative small area (the freezer) before being recycled through another expansion valve to the refrigerator, and finally compressed again, starting the cycle over.

In a home A/C unit, Freon on average can only “cool” the air by approximately 20 degree below the ambient temperature.

In excellent insulated homes, you can get close to 25 degrees.

Theoretically, A/C units and freezers/refrigerators are permanently sealed systems that should never need to be recharged; the “coolant” never wears out so to speak.

All you are doing is compressing it to a liquid, then forcing it through a valve into a gas…it never gets contaminated or used up.

In reality, most systems, as they age, will develop very small leaks or require repairs…small amounts of Freon in your home atmosphere are harmless, ammonia on the other hand…

As Randy pointed out, propane can be used, as can natural gas…almost any compressed liquid, even water, will “cool” as it expands into a gas, some are more efficient than others.

In fact, the first home refrigerators used natural gas, propane or ammonia.

But then again, they didn’t require seat belts in cars back then either.

18

Has anyone yet pointed out that it’s ANHYDROUS ammonia that is dangerous? That stuff gets watered way way down as a laundry additive. Also, it’s the active ingredient in modern-day “smelling salts,” IIRC.

OTOH don’t ever mix ammonia with chlorine bleach. That would produce mustard gas, which is highly toxic and potentially lethal. Despite the occasional column in newspapers, women’s magazines, etc., every year someone cleaning the bathtub succumbs to the fumes that result from mixing these two no-no’s, keels over, and dies. Many more suffer inhalation problems.

19

The limiting factor is temperature differential in a residential A/C is the sizing of the unit relative to the heat load and not the type of refrigerant used. It should be noted that different types of “Freon” will have different optimum operating temperatures - the refrigerant used for a home A/C will be different than the refrigerant for a refrigerator (the A/C refrigerant will probably have a lower vapor pressure at a given temperature than the refrigerant for a fridge).

One thing that ammonia has for it is a very high heat capacity, slightly higher than water. Another advantage of ammonia is that it has a much lower molecular weight than any Freon (or even propane), which reduces pumping losses. The lower molecular weight will also improve heat conductivity, so larger tubing sizes can be used to get the same heat transfer.

20

See, you can learn something new every day!

A buddy and myself installed my home A/C, (he has the license, so we are all good there) and he was explaining how the system worked and why.

I knew ammonia was “easier” to compress, but not why that was so, and I knew it was more efficient as a coolant, but again, not the why part…now I know!

When we were shopping for the A/C equipment, I really wish I could have spent the extra 2 grand and picked up the Kelvinator Industrial unit…designed for small office buildings, the guy at the A/C supply store said it would cool the “normal” home in our area at twice the speed of the 2 ton units, and could get it as cold as you could stand, even with the small amount of attic insulation prevalent in the homes built around the time mine was.

The 2 ton unit we have has to work pretty hard to over come the 100 degree plus days in summer, and I have R30 insulation up top.

Thanks for the info Erik…