Hot water demand

[Keef]

I am trying to calculate the heating load for hot water in a hotel. From various guides, I have been able to find out that is is usual to allow between 25 and 30 gallon/day per person. I am looking at sizing a plate heat exchanger but the only information I can find in the guides refers to storage units and calculating their recovery time.

Can anyone tell me how much to allow for peak demands?

Keef

 

[pedarrin]

Hot water demands for hotels have peak periods. These usually occur in the morning when most people are taking a shower/bath. It also might occur during meal times fi the hotel has a large kitchen/restaraunt.

Therefore, when sizing for hot water demand, you will almost certainly want to have storage capacity. If you do not, then your heat exchanger, unless it is an instantaneous type, will have to be sized to produce according to this peak usage all the time which will mean it will be underutilized most of the other time. This will mean wasted energy.

Most of the companies which manufacture water heaters and boilers have systems or software which allow you to size for your demand. Contact your vendor and ask them to help. I personally like A.O. Smith and Aerco.

 

[IRstuff]

Another option is point-of-service heaters, although I suspect that's a bit more expensive.

TTFN

 

[pedarrin]

If you are talking about the ones which are the small ~ 6 gal tank types which can be located above the ceiling, then they are not too bad for lavatories but if you have a shower, they are too small. You would have to have them for each room. That would be expensive up front. Plus more equipment means more maintenance and that would be expensive down the road.

If you are talking about the little tankless electric heaters located under that lav, my experience has been that they are maintenance nightmares. Plus they would not serve the showers. I tend to use them when I do not have too many fixtures and the fixtures are located a distance from the main water heater.

For a hotel, you would still need some type of central water heating for the kitchen and laundry facilities.