Cooling Load created by a bank of showers in confined space

[jwelle]

We are bidding a job that has been crazy from the get go. A yoga studio with radiant floors, 200 degree steaming sock ducts, a specially built Aaon with a 60 degree heat rise to achieve a 105 degree fitness floor, and a unique owner who is her own GC.

All of that aside, we got stumped on a small part of the cooling load calculations for the locker rooms. Apparently, all of the showers will run practically non-stop during parts of their business day, and we were surprised that none of us knew numerically what that would do. Grabbed the ASHRAE, nothing. Online, nothing. So it is an interesting question, and I'll pose it again.

What is the cooling load/heat gain of a 2.5 gpm shower running for an hour at 105 degrees? Any takers?

Thanks!

 

[willard3]

This load will have both sensible and latent components and I will guess the latent load is far higher than the sensible.

 

[EnergyProfessional]

it depends on the acceptable temperature and humidity in the shower room. if you want 75°F and 50RH, the load is huge. If 80°F and 90% RH, it will be less, much less.

you also have exhaust, most of the vapor gets exhausted. In your other post you said you wanted to ignore exhaust, but how can you ? this has major influence. the whole purpose of exhausting showers is to get rid of humidity and is required by code. so the ignoring exhaust is just a moot point.

 

[jwelle]

Yes, exhaust is going in at code by the plumbing contractor at 80cfm per fixture, however the fully tiled (floor, walls, and ceiling) shower rooms will be exhausted as well. But, for calculating the cooling load, wouldn't you need to know what those 6 showers put off. Wanting an RH of around 60 and a temp around 72°. It's needed as much to calculate exhaust as anything else, right? Just because you exhaust it doesn't mean it never happened, right? I have been wrong before.

What a few people have come up with, and it only accounts for the sensible side, is 105° degree water = 199 watts = 679 btu. This is limiting but it is a start.

I know you're never going to get the RH in the actual shower area down to 60, but the area directly outside the walkway needs to be down there. There are no doors in the entire locker room. Yes, there are so many mechanical solutions to this. I'd still like to be able to put a number to it.

 

[EnergyProfessional]

if you transfer air from the walkway, there walkway should be fine since little will diffuse there from the showers.

why the 72°F requirement? People in showers likely want it much warmer. If they wanted it colder, they didn't use 105°F water.
Exhausting the air is like it never happened, at least for the building. Obviously the makeup air you bring into the building elsewhere will create a load.

i wouldn't worry too much. If your surrounding transfer air is 72°F / 60RH, and you exuast at that large rate, i doubt the shower will get over 80°F, whihc should be fine for comfort assuming people are naked and wet. If they are too warm, they can turn down the water temp.