How the New York City steam system works

Re:How the New York City steam system works by burlesona on Sunday October 30, 2022 @12:26AM (#33391073)

So they claim this is the cleanest way to deliver energy, but that’s very unintuitive to me. It seems like there would be a huge transmission loss in piping hot steam through the whole of Manhattan, and I didn’t think steam engines were particularly efficient. So my intuition is failing here.

For those in the know, what makes a steam system like this effective as a clean energy distribution system, and how does it compare on a cost basis?

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Re:How the New York City steam system works by tb_technical on Sunday October 30, 2022 @12:57AM (#33391233)

https://www.esmagazine.com/articles/83622-heating-with-steam...

It looks like it's efficiency has to do with the fact that it's an entirely passive heating system - it doesn't require any infrastructure except laid pipe to operate.

(I went on a Google quest after reading your comment and wondered the same thing. Thought I would share...)

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Re:How the New York City steam system works by retrac on Sunday October 30, 2022 @02:09AM (#33391635)

Not to get off topic, but "steam engines" still drive the whole world; whether nuclear or gas or coal fuel, or concentrated solar power, steam turbines are how heat is turned into motion to make electricity. Modern ones operate very close to the theoretical limit of efficiency (around 40% [1]). The great advance James Watt made in the late 18th century, was a technique to recapture heat from the exhaust and raise practical efficiencies to several percent, with the remainder of the theoretical limit eeked out progrssively in the following century.

One of the ways that limit is approached is to use the highest temperature difference the materials can stand; steam for large turbines is hot. The exhaust is still steam, but no longer hot enough to drive things efficiently. Indeed, the cooling loop of many plants run steam-hot, just not superheated-hot. Another common district heating approach (used in NYC) is a small direct gas-fired turbine driving a generator, with steam cooling. Combined generation is the use of that waste heat, for other heating purposes, and can raise total system efficiency. In Sweden, you can get unlimited heating for your pool in winter, if you live close enough to the nuclear plant! The heat was just going to be dumped into a cooling tower, otherwise. (I think that system is hot water, not steam distribution, but same idea.)

The pipes are indeed heat-leaky, despite usually being heavily insulated.

[1] https://en.m.wikipedia.org/wiki/Carnot%27s_theorem_(thermody...

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Re:How the New York City steam system works by electroly on Sunday October 30, 2022 @05:34AM (#33392764)

> gas or coal fuel ... steam turbines are how heat is turned into motion to make electricity

While steam turbines can be found at natural gas plants, it's typically only for waste heat recovery in combined cycle plants. Primary generation is more commonly done with combustion turbines, which are more like jet engines. They don't use steam.

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Re:How the New York City steam system works by marmetio on Sunday October 30, 2022 @02:14AM (#33391670)

They're just referencing the earlier claim that the new natural gas boiler is cleaner than the old coal boiler. The sentence is worded incorrectly, and doesn't claim to be a cleaner distribution method either. They said they keep it because it's too difficult to sufficiently upgrade the buried electrical distribution system.

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Re:How the New York City steam system works by whiddershins on Sunday October 30, 2022 @06:47AM (#33393234)

My understanding, as I mentioned in another comment, is that to some degree this steam is waste heat from generating electricity (where does the steam go after it turns the turbines?) so basically free.

Possible I’m misinformed.

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