air conditioning super crowded spaces in extreme heat


I was wondering this while watching Barbie in a sold out house on a heat advisory day in NYC.

The air conditioner had definitely malfunctioned because it was incredibly hot in the theater but it must have been running or else it would have been unbearable to be inside with that many people. The outside temp (extreme) and the number of people inside and their body heat defeated this air conditioning system but I was wondering how? How do institutions compensate for large crowds and extreme outdoor heat and what is happening when the ac is working by outmatched by circumstances?

In: 2

In your house you might have an AC that sits in your window and runs off a normal electrical outlet which can only be so powerful. In a commercial building they would have an extremely large AC unit (or several extremely large ones), often located on the roof, and they pump cold air throughout the building with ducts. This is more similar to a central air conditioning system which some houses do have, but even larger.

An AC can only move a certain amount of heat. Just like a standard space heater can produce heat at a rate of perhaps 1000w, a standard AC can remove heat at a rate of say, 2000w or for a large commercial building maybe it can remove heat at a rate of 50,000w. The problem is, heat gets back into the building in a few ways: leaking in through the walls (this happens when it’s hot outside) and being produced in the building (this happens from a lot of people being there as your body produces heat just living normally, and it also happens from equipment like lights and projectors and speakers).

Combine a lot of heat (people and electronics) inside and a lot of heat (hot weather) pushing its way in from outdoors and your AC might keep the inside cooler than outside, but it might not be cold *enough* to be completely comfortable.

I work in commercial HVAC design. We use published values for how many people are estimated in a space at peak usage and how much heat and humidity they produce while doing that activity (along with any electrical equipment, how much heat is transferred through the roof and walls, etc). This tells us how many tons of cooling we need to provide. It is a balance as well, because if you oversize the equipment it can counterintuitively increase the humidity in the space, and will also cause the units to turn on and off more frequently (short cycling), which causes wear on the equipment.

In your experience, it’s possible that one of the HVAC units wasn’t working, or maybe it was just a poorly designed system which wasn’t able to keep up with peak load.