In the center an empty (with air) not thermally isolated room with concrete walls, floor, and ceiling, there is hanging on a non thermally conducting thread a device ("conditioner").
The weather is stable (that is the temperature outside the room does not change).
The device is equipped with a very long longevity battery.
Is it possible that (thanks to the conditioner) the temperature in the room will remain significantly (say, 3 Celsius) below the external temperature for a long time?
The essence of the question is that the conditioner cannot "suck" the heat out of the room because the device does not touch the walls or anything outside. Can a conditioner work under such restrictions?
Edit: The elements of the device cannot have very high (=infinite) heat capacity. (The only "infinitely big" thing here is the longevity of the battery.)