I have a room full of air where the temperature is kept at 30°C using a source of 2000W (wall mounted AC unit).
Oil is kept in PVC barrels(4mm thick) overnight (8h) in the room to increase it’s temperature from 5°C to at least 20°C.
I’m having a problem with the oil volume. It seems like it’s not warming at all…
I think that you have a misconception, because you are simulating in steady-state, while your end time looks like you want to capture the transient behavior. In steady-state, the time is just for counting the iterations.
I would start by fixing this. For a first simulation, keep steady-state, set the end time to 1000 and the Delta t to 1, to find a converged simulation and check that the temperatures converge.
Afterwards, you can switch to a transient simulation and actually solve for the time period that you wish.