New portable AC needs single circuit outlet, what does that mean, and how can I tell if my outlet is the right kind for my 14K BTU AC?
A single circuit outlet is one that is wired to the panel and does not engage or connect to any other outlets or appliances using electricity. The purpose is to eliminate/reduce additional current draw preventing breakers from popping from overload, or fires from starting caused by faulty breakers.

You can determine if you have a genuine single circuit outlet by plugging lamps into all of your outlets. Flip each breaker off in turn. If only one lamp goes out, you might have found your objective.

You can "work around" the single circuit restriction if you identify with certainty the outlets shared with the one you've chosen to use with the unit. Turning nothing else on while the A/C is in use will prevent the overload, possible breaker trip or circuit failure/fire.

If, for example, you discovered that your television is connected to the same circuit you've chosen for the A/C, it may draw enough total power (A/C and TV) to pop the breaker. It's a sure thing that you would not use a 1500 watt hair dryer while operating your A/C on the same circuit. Some televisions draw very little power, so that appliance may have been a poor choice.

Because the second option involves human engineering, it is more prone to human error. An example from my world is the kitchen circuit. One microwave oven running in convection mode and one toaster oven running in baking mode is more than the non-single-circuit breaker can handle. We know not to do this, yet it happens often.

Regarding the use in your building, it's less certain, but the A/C unit is merely blowing hot humid air out the window and would not be visible as a protruding box, as would a window unit. It seems likely you would be able to use it without complications in that respect.