Buried Generator Shed?

I built a shed (not a bunker) and made the mistake of thinking an exhaust and intake fans would be enough. The temperature rapidly increased by about 25+ degrees Fahrenheit. Added a direct exhaust port lined up to the engine exhaust and the increase dropped to under 10 degrees Fahrenheit. So, make sure you let the hot exhaust out of the bunker without mixing with the basic incoming air. Also make sure the exhaust pipe is insulated so that it doesn't radiate heat inside the bunker. I placed my output vents up at the top of the enclosure. Turns out I needed another one closer to the generator, but there is no easy way to add that vent. There is also a lot of hot air coming from the cooling vents on the generator. I think this is the second major source of heat. You should have an output vent placed by that source of the heat. If I had done these things, more of my heat would have been piped directly out of the enclosure instead of mixing with the air in the enclosure, and I wouldn't have had to keep adding fans to the enclosure in an attempt to keep it cool.