Re: Gas Refrigerator (was 25 Hz Power)

In the 1970s this all changed with the energy crisis. I believe the

> domestic gas sources ran out and now gas had to be imported from the > Middle East along with oil, greatly increasing its cost. Indeed, > there were shortages and new housing construction had to use > all-electric instead of gas.

I think some is imported these days, but most is domestic, if you count offshore. I do remember the big push for cryogenic tankers and such, but recently they have been building gas powered power stations, which means a ready supply at a good price.

After the railroads diselized, the diesel locomotives had to contain a > water boiler for passenger trains to provide steam for a/c and heat. > This continued into the Amtrak era. Amtrak converted all trains to > all-electric, eliminating the steam lines which were a problem to > maintain.

I guess you mean HVAC. I doubt the propulsion is all electric on the Chicago to New Orleans run. BTW, I just checked that it still runs, but they have renamed the Panama Limited to the City of New Orleans, which was canceled years ago.

Someone mentioned Philadelphia's central steam for heating. This was > once supplied by the Philaadelphia Electric company in a "steam loop" > that circulated throughout center city. Buildings purchased steam > instead of maintaining their own boilers. I believe industrial > processes could even use that steam. The loop still exists although > it was sold off. The steam generators for the loop may no longer be > from the electric power plant; Philadelphia Electric has closed down a > lot of old power plants. One beautiful old building is being > converted into condos. Anyway, the steam loop has had varying > fortunes over the years, becoming less popular, but then gaining in > popularity again. I believe other cities have similar utility > service.

The University of Illinois at Urbana, at least in antediluvian times, when I was there, owned an operated a power plant. Originally the electricity was the main product, and the steam to heat the buildings was a byproduct. When I was there, it was really a steam plant that generated some electricity. For TDers who aren't engineers, all heat engines work off a temperature differential. You not only need a source of heat, but a sink, the colder the better. That is why they build power plants near bodies of water.

Someone mentioned Bell using jet engines for central office power > backup. I'm kind of surprised at this. The electric companies use > them for summer supplements. They are very expensive to run, but > can get up to speed very quickly. I believe the phone companies use > more conventional diesel engines to power generators. If there is a > power failure, central office battery has enough capacity to keep > things going for a while, more than enough time to power up a diesel > engine. (The jet engine has the advtg of being smaller.) Many use > diesels, but some have turbines. I have been told if you are ever > near one of the latter and notice the louvers opening, run. The > noise will be horrendous. There must be a scale at which gas > turbines become competitive with diesels, or power companies > wouldn't use them either. Of course, they aren't quite the same as > aircraft turbines. They are multi stage to milk as much energy as > possible out of the stream. Oh, and steam plants generally drive > multi stage steam turbines. > [TELECOM Digest Editor's Note: They did this same thing in parts of > downtown Chicago. The boiler in the basement of the Commonwealth > Edison (corporate HQ at that time) Building provided steam to many > buildings in the area.

To tie this back to telecom, here is an even weirder one: Until a few years ago, the headquarters of the British overseas telecom giant Cable & Wireless was a building on Theobalds Road in London. It had originally been a central hydraulic plant. I think they provided high pressure for elevators, but, more importantly for C&W, they powered and owned a pneumatic mail system that covered much of central London. This was one of those systems where you could put papers in a cylindrical carrier and fire them to the recipient by air pressure. When the government allowed C&W to compete with British Telecom, they were able to use the tubes from the defunct mail system to run fiber into most of the "City", being the financial district.

[TELECOM Digest Editor's Note: University of Chicago also has (or had, as I have not been around there for more than a decade) a steam boiler over at 61st and Harper Avenue I think. In the dead of winter when there was otherwise several inches of snow on the ground, you could always tell where all the underground steam pipes (to the various buildings on campus) were buried, because no matter how much snow had fallen the night before, that spot would always be free of snow and ice. PAT]
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John McHarry
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