About hotel hot water calculation

[GUO ZHIQIANG]

Hi all...
Now, I'm designing a hot water system for a hotel.
The owner requested that an electric water heater located on the roof be used to supply 100 rooms with circulating hot water pipes.
I would like to know if there is a code or standard that specifies how to do the hot water calculation, such as outpower of electric water heater, the size of the hot water tank, etc..
Thanks.

 

[GUO ZHIQIANG]

hello,everyone!

 

[hacksaw]

Check the local building standards in your area. The building architech can advise.

 

[GUO ZHIQIANG]

I would like to know whether there is something in the American standard

 

[LittleInch]

How to do the calculation is not what codes and standards are for.

Heating by electric is not that common if gas is available due to the energy required at peak periods.

Electric will need quite a large tank so that your heating can take place over a long period compared to the peak demands, usually in the morning especially when everyone has a shower then a bit less condensed but higher usage in the evening when people also tend to have showers or baths.

"The American standard" is very vague. Which one were you thinking of?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Try this and get the research paper mentioned?

https://go.gale.com/ps/i.do?id=GALE...serGroupName=anon~db53822c&aty=open-web-entry

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[mk3223]

As an example, may refer to the link of the California Energy Code of the water heating system for the nonresidential building,

https://www.energy.ca.gov/sites/default/files/2021-03/2019 WH - NR, HRR, HtMt v4.0 ada.pdf

 

[GUO ZHIQIANG]

THANKS EVERYBODY!!! I THINK I FIND IT!!!

 

[PEDARRIN2]

One of the ASHRAE handbooks (cannot remember which) shows the modified Hunter's curves for hot water. The charts are useful for showing the interplay between generation (KW of the heater) and storage (gallons). One caveat is Hunter's is very conservative so you need to consider that.

 

[LittleInch]

For a hotel, conservative is probably the best way.

If hotel guests, especially business ones, can't get hot water on demand in the morning or any other time of the day, but morning is critical, they complain bitterly and don't come back...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[PEDARRIN2]

LI

Yeah, nobody complains about having too much hot water.

But, when the conservative guidance can be 2-3 x what is actually needed, it is not in the owner's best interests.

 

[EdStainless]

The trick to these systems is have enough flow to keep the water near full temperature without wasting power or causing undue erosion of the piping.
The other questions are related to pressure control in a multi-floor hotel and should the recirc loop be split into multiple sections.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[LittleInch]

In other words it's DESIGN.....

The guides if they are that bad then you need to use some common sense and either allow for some additional heating power later if it proves to be underpowered or reduce the volume int he tank versus the heating power needed in your peak 15 mins.

Also think about how the water temp is regulated at the point of use and what your acceptable temperature range is for the "hot water"

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.