Ventilation question

I'm new here so I apoligize in advance if I'm asking a question already on here but I've looked every where and can't seem to find a solid straight forward answer. I'm setting up my first grow room and can't find any information on cooling a NON sealed grow room. I don't really want to do a sealed room and have the added expense of burning c02. I want to do a passive intake the only problem is it's the middle of summer and I don't see it being an option to bring in hot air from outside. What are my options as far as cooling and utilizing the c02 rich air from outside? Would an window a/c unit pump enough cool air from outside? Im just worried my exhaust fan would be exhausting hot air faster than I could replenish the room with cool fresh air. I'm sure these are dumb questions to a lot of you but I'd appreciate any advice anyone has.