light trap window question

i'm going to attempt my first grow in my closet i'm goin to start off small with one to two medium size plants in soil n work my way up to 24-32 plants either SOG or ScrOG in hydro with 1 or 2 plants in soil. I've received great advice already on here about lighting so I'm going to go with a 600w Hps air cooled system for the my closet which later on after a harvest or two will just become a flower room, I'm thinking about opening my closet door to keep temps down, I don't know if i should go with that, or setting up a ventilation system or both...

so what do u think? I'm leaning more towards keeping the door open. And for my main question If i keep the closet door open will black trash bags over my windows in my room where closet is work as light traps?

add ventilation. if the temps under 90-95f w/the door closed i would keep it closed. are you using something to reflect the light?

the inside is painted white and i'm going to use a black/white polymer to make a false door to ventilate n reflect

sounds alright, what type of exhaust setup are you going to use?

http://forum.grasscity.com/do-yourself/598023-%2Abasic-diy%2A-modifying-stanley-blower-cooling.html#post7453073 might as well give this a try even tho i'm not to much of a DIY guy