Super slim models produce less heat than phat & early slim models.
If the fan is producing too much noise, you can reduce the fan speed from 40% to 30% in /setup.ps3
However, the ps2 emulator uses more cpu power than ps3 games. So your ps3 could overheat after certain time at 30%.
But the temperature depends also of other factors like your rooms temperature, air flow, ventilation of the area, game played, etc.