It seems like such a huge amount of water and would require so much energy to get it that high, plus there’s the waste to deal with

57 points

Waste is easy, it goes down.

For pressure, high rises have a pump in their machine room that pumps water upwards. It used to be water towers on the roofs of buildings that aides pressure

permalink
report
reply
60 points

A bit of an elaboration on why water towers are used in combination with pumps. Pumps are great for moving a constant amount of water around at whatever rate the pump is designed for (e.g. a small pump will move something like 1 gallon per minute). a big enough pump (or series of smaller pumps) can cause that pumped water to consistently flow at that rate.

The problem is that people don’t use water at a constant rate. In the morning, several residents probably all run the shower at the same time. if too many people open the water tap at the same time, a pump will give each just a fraction of what they expect.

But a water tank high up supplies water by gravity, you could open a large number of water taps, and as long as the pipes from the tank are big enough they’d all have the same pressure as if just one opened.

The water is gradually pumped up to the tank no matter if people are using it or not, then when many people want water, they all get it at expected pressures and the tank start to empty. Eventually people close the taps, the tank will slowly start to fill again from the pump.

This same basic design is also how water towers supply water to many single story buildings, it’s not a unique engineering feat for skyscrapers, but an adjustment to fit somewhere within the building’s footprint.

permalink
report
parent
reply
27 points

And water towers are still used to manage water pressure demands in municipalities.

permalink
report
parent
reply
23 points

Yeah - if you’re in NYC at any point and go up anywhere you can see roofs of a lot of buildings, you’ll see a TON of water tanks and towers on older stuff.

permalink
report
parent
reply
24 points
*

Example:

source

(It’s not just older stuff, by the way. They’re actually still made of wood like that to this day, because it’s apparently the best way to do it.)

permalink
report
parent
reply
13 points

All i know about NYC, i learned about in hey Arnold. I would be disappointed if i go to NY and find that there are no water tanks and gardens on roof tops

permalink
report
parent
reply
16 points

Back when I lived around the 30th floor, I would turn on the tap and then wait 10 minutes for the hot water to arrive.

The trick was to wait until the people above you were having a shower, then it would already be hot.

permalink
report
parent
reply
45 points

I’m no expert, but I’ve looked at this in the past. Most large buildings have their own water tanks inside them. If you think of an image of a New York skyline away from the skyscrapers you might picture small water towers on top of most of the buildings. Those are the tanks that supply water for the building. Skyscrapers will have multiple tanks inside the building itself, maybe one every 5 or 10 floors up. There will always be one at the top of the building but it might not be as obvious looking as a small water tower. Each tank will serve just the floors in between it and the next tank below. When the tank needs to be refilled it just draws from the tank below it. This way the building doesn’t pump all the water it needs all the way to the top floor; it only pumps water as high as it needs to go. Keeping water in a tank means it still works like a traditional gravity-fed system and should function for a while even in the event of a power outage.

Handling wastewater is relatively easier, it still just needs to flow down. The pipes just drain into one or more pipes going down to the bottom of the building.

permalink
report
reply
5 points

It still has to pump it the elevation though?

permalink
report
parent
reply
13 points

Yes.

Take New York for example. It is my understanding that New York’s municipal water system has enough pressure to pump water 5 stories high, so many of the relatively smaller buildings have large wooden water tanks on their roofs to keep that building’s water pressure relatively constant even during peak demand times. Larger buildings are responsible for pumping their own water hundreds of feet into the air.

permalink
report
parent
reply
5 points

Yes

permalink
report
parent
reply
2 points

Yes, but multiple tanks throughout the building means they don’t have to pump all the water all the way to the top. They only need to pump the water for the highest floors to the top.

permalink
report
parent
reply
3 points

Ah, thanks for the clarification. That makes a lot of sense.

permalink
report
parent
reply
24 points

Plumber here. Unless we’re talking about sky scrapers the grid pressure is generally enough to lift the water to the top floors. As long as it’s lower than the city water tower there’s no issue. If it’s a flat terrain or the building is on a hill then yes, you might need a pump to boost the pressure. Sewage on the other hand is not an issue - gravity takes care of that.

permalink
report
reply
8 points

Can you recover energy on the way back down?

permalink
report
parent
reply
12 points

Hydro-excrement energy

You’re a fucking genius

permalink
report
parent
reply
5 points

Finally, “shit-ton” would be a legit word. “This high rise produces 8 shit-tons of energy per month!”

(…considering when fuck-ton will have its day as well…)

permalink
report
parent
reply

Pump and dump.

permalink
report
parent
reply
7 points

Classic sewage turbine.

permalink
report
parent
reply
2 points
Deleted by creator
permalink
report
parent
reply
4 points

I guess you could but probably wouldn’t be worth the cost of such system.

permalink
report
parent
reply
21 points

How Water Towers Work | https://www.youtube.com/watch?v=yZwfcMSDBHs | by Practical Engineering

High buildings sometimes have their higher floors above the height level that the water pressure from the water supply of a town can reach.

Those buildings then use pumps in the cellar to either pump the water to a tank on the highest floor and let it fall down again to the floors or to pump the water to the floors directly.

permalink
report
reply
17 points

Much like the internet, it’s a complex system of tubes.

permalink
report
reply
2 points

It’s not a big truck!

permalink
report
parent
reply

Explain Like I'm Five

!explainlikeimfive@lemmy.world

Create post

Simplifying Complexity, One Answer at a Time!

Rules

  1. Be respectful and inclusive.
  2. No harassment, hate speech, or trolling.
  3. Engage in constructive discussions.
  4. Share relevant content.
  5. Follow guidelines and moderators’ instructions.
  6. Use appropriate language and tone.
  7. Report violations.
  8. Foster a continuous learning environment.

Community stats

  • 983

    Monthly active users

  • 84

    Posts

  • 899

    Comments