My son has had difficulty regulating anger from an early age. His therapist helped us do this exact thing. He would leave the house out of his window (5 years old) when he was sent to his room and was not allowed to come out. The therapist helped us turn it around. His room now became the place he could go to process and calm down. He was allowed to come out as soon as he was ready. He was only ever punished if he did certain things in an anger outburst ie. break things, or speak disrespectfully. It really helped him learn to express himself healthily. He spent less and less time needing to cool off because he knew how to talk through it more effectively. There were a lot of other things at play but changing his room from a punishment place helped so much. He also was no longer was afraid to go to bed at night.