Comment on Why is there steam coming out of the streets in New York
Hikermick@lemmy.world 1 year ago
Some big cities originally heated their buildings by producing steam in one one centralized building and delivering it to large buildings thru pipes underground. The steam you see is from leaking pipes in this antiquated infrastructure. It’s a very inefficient method if you ask me. Cities should offer these buildings low interest loans so they can update and be independent but they never take my advice
District level heating is actually pretty efficient, some universities do the same thing on purpose to save on bills. Our relatively young city does it with the downtown skyscrapers for the same reason.
The other nice thing is that when you upgrade the heating system to be less carbon intensive, you can instantly have a ton of buildings all jump instantly to fewer emissions too.
Afaik it’s not inefficient if the heating is done via fossil fuels as big furnaces (especially in the past, especially turbo-fan super-fine grind coal ones) are much more efficient than smol ones for individual buildings (even if the buildings are giant).
It’s terribly inefficient. The efficiency is lost when the steam that condenses back into hot water is lost and none of it is returned to the boiler to be reheated. Rather than reheating this returning water which normally is at 120-160 degrees Fahrenheit, fresh water is used which in the winter here is around 56 degrees. Aside from this the cold water taken in contains impurities such as dissolved gasses which cause corrosion and dissolved minerals which can cause scaling that acts as an insulator raising the amount of energy needed to heat the water.
Oh, I didn’t know it was a one-way system in NY.
A weird decision, but I guess it lowered the initial cost a bit?
I can’t speak for NY but that is the situation in Cleveland. I have a customer downtown on city steam. I watch hot water discharge to a drain at the rate of about 3 gallons a minute and there’s 1440 minutes in a day. When it was built I’m sure they reclaimed most of it (80% return is considered good) but over time the pipe corrodes and you have leaks.
The difficulty was drainage. Isolated steam systems in steam era construction were designed to use gravity for condensate collection. It’s one of the reasons boilers are always in the basement of old buildings.
Steam system engineering was a well-compensated profession. A well-designed system would accurately predict the rate of condensate flow for every part of the building, prior to construction, and reflect these predictions in the slope/grade and diameter of the steam pipes. Inaccurate predictions resulted in problems like pipe knock (aka steam hammer) which you can often hear when you or a nearby neighbor partially close the shut-off valve of a radiator.
Since construction in the city had many elevations and could not be predicted in advance, there was no equivalent solution to facilitate condensate collection. The system had to be one way. And yes, it’s inefficient compared to modern systems, but was innovative in its day.
Why not just have the city mandate the upgrades and then implement them? It’s probably not that big of a problem for everyone involved.
If it were that simple everyone would have done it by now. This method of heating your building is very expensive. Long story short, I’m in the HVAC business and two of my customers have made themselves independent. One was a private property management company that gutted an empty building and was successful, the other is a federal building that hired a private company to convert over and got screwed.
I made the same suggestion you did, all I changed was that the city pay for and implement the changes instead of handing out money to random people in the form of loans that may or may not get anything done.
dickalan@lemmy.world 1 year ago
Boy, I sure love it when dip shits act like they’re from Reddit and talk about stuff they know absolutely nothing about, why don’t you shove your foot in your mouth and stop typing