Commercial HVAC "cutoff switch" tied to the record button in large studios and sound stages. How do these systems avoid short-cycling the condenser?

I have a couple of questions about large commercial HVAC systems as they are employed at large offices and recording studios around town. My understanding is based on past experience with residential AC, and I'm mostly self-taught so please excuse any obvious conceptual gaps. I enjoy learning new things.

I live in Los Angeles and work in the entertainment industry: by day as an IT systems engineer, and occasionally gigging around town as a professional singer.

LA has several large concert halls and film soundstages. Live recording is often performed for hours on end, but the space must remain adequately cooled and ventilated to ensure comfort.

One of the most common vibration- and noise-mitigation techniques is chosen during the architecture phase: physically installing the chillers and air handlers in a neighboring building or at a central plant far removed from the recording space. Despite the use of a wide range of other noise-reducing techniques (acoustic baffles, false floors, double-insulated doors and "room within a room"), even the slightest movements of air can still be detected by a condenser microphone.

When the red light goes on and off, there is a loud clunk. I assume is a large switch closing and opening. By listening to the "room noise" from a device elsewhere in the same space, I can hear a profound difference in sound level as the system kicks on and off.

During a typical recording session, the room is not actively cooled for several minutes at a time, possibly up to an hour or more, and cooling may be cycled on and off several times per minute. If someone were to intentionally kill the fan in a residential system but leave the condenser running, my understanding is that the pipes would freeze up and fail due to the lack of heat exchange. How are these large HVAC installations designed to prevent damage to the cooling system? Is it simply not possible to "freeze" a chiller or cooling tower in the way that is possible with residential HVAC? Are large systems cooled with water alone, or with some gaseous equivalent of R410a?

submitted by /u/eaglebtc
[link] [comments]