underground parking temperatures
What temperatures are expected in underground parking facilities underneath the main building?
In Berlin, Germany, I did a external CFD analysis of the ramp and opening of such an underground facility with different wind directions, temperatures outdoor, wind speeds, ect. My conclusion was that the air change rate was roughly 2-3 ACH depending on summer or winter and that the actual penetration of air was not very deep into the underground. High exchanges were at the ramp, but deep inside there was not much moving.
In this facility there where technical rooms generating heat in the perimeter spaces of the parking area.
I ran an annual simulation in TrnSys using the ACH from the CFD simulations to estimate the temperatures resulting in the parking area. I came to 10-12 deg C, roughly in winter when outdoor temps were about 3-4 deg C. The 24 hr variance was very low (almost flat line) in winter and only about 4 deg C in summer. Although Berlin does have its hot days, the yearly temps are about 10-12 deg C and even in summer only about 18-20 deg C.
I believe that modelling (that's UK English for modeling) of underground parking spaces as "adjacent to outdoors" is a bit overkill. I think modelling it as a space with a infiltration rate of 2-3 ACH is more realistic. Obviously, I consider the "depth" of the underground area relative to the ramp opening.
What are your experiences?
For reference here is an older post about underground garages. Not the same question as your but may have helpful information.
Jean, is the ramp always open to the outdoors or do you have some kind of garage door?
I also assume it would be pretty dependent on the exhaust fan situation: how much airflow you're pulling out, from where, and how it's controlled (24/7 or based on CO concentration). I'm not aware of the German mechanical code, but it's probably not far off what's in the International Mechanical Code section 404.2