Eli5: How does a hotel always have hot water for every occupant?
In: 1975
I can answer this!
MASSIVE hot water tanks! I worked at a hotel with only 66 rooms once, and we had 3 10,000 gallon boilers/tanks. Something that helps as well is that faucets don’t get as hot as typical residential faucets, which reduces hot water usage. I can’t remember because it’s been a while, but faucets are set to only get to say 100*F, and when the boiler keeps water around 130*F that means that you’re using a lot less of the hot water in the mix, reducing usage. Hard for guests to take long hot showers when the water isn’t so hot.
Basically an industril-sized boilers.
Hotels consume a LOT of heated water, and that water needs to be at the ready.
So a giant boiler keeps a LOT of water hot for baths, laundry, kitchen and pools.
Also the boiler produces a lot of vapor, which can be used again, in laundry, kitchen and heating.
Source: Have designed several Hot water/Vapor systems for hotels.
They don’t always… I’ve been on trips where I stayed in a hotel and if I took a shower between 6 – 8 am I always had luke warm or cold water. If I showered outside of that range say 5 am or 9 am or even the afternoon at 2 pm or 4 pm or evening at 9 pm I always had hot water. Sometimes they don’t have enough capacity but you’re using it when other people aren’t so you have hot water.
They don’t always. Stayed at a hotel on NYE, ran out of hot water. Seemed like they had the hardest time catching back up too, it was out for over 12 hours.
In addition to what people said about volume the hotels most likely have a circulating loop. The hot water is constantly circulating past the rooms so it’s available very quickly.
Hotel I worked at had solar powered boiler thing on the rooftop of each bungalow. Never had any complaints about it. It is in the tropics so enough sunshine I guess.
When designing the system you estimate the average high limit use of hot water and max capacity, then scale the heating system accordingly to meet that demand. It isn’t any different from properly designed household system, just bigger in scale. Most household underestimate their need on cheap out and choose a system that isn’t big enough for their actual need.
The math isn’t really that complex. You know what kind of showers, for example, every room has and if they all use hot water and max pressure how much material flow that is (in volume/time unit). Then you just scale up your heating system or storage capacity to be able to provide at least that much for a certain amount of time.
Now how you pull this off in practice. Well it is entirely up to you as a hotel owner when building your hotel. The systems wary greatly in execution depending on local sources of energy, their cost, how many floors and rooms you have, what kind piping you got, how much you estimate the use to be.
But to ensure there is always hot water when you turn the tap, you circulate the hot water circuit constantly and you keep the pipes insulated for minimal heat loss.
Are combi boilers not a world wide thing? TIL
Hotels I have worked in have recirculating pumps that basically constantly have flowing hot water in insulated pipes to be able to transport hot water to the room that is calling for it.
These pumps run almost continuously unless absolutely no one is using hot water. In a hotel, that would be a rare occasion.
In Europe (at least in the Nordics), a lot of cities have central plants that produce a shitton of hot water that is then distributed in the city. This hot water is used both for heating and for regular hot water use. I’m guessing hotels here are connected to this system as well, since it basically means ”infinite hot water”, and no waiting.
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