After months of experimenting with different methods for better cooling the basement server room where 60+ systems are running Linux benchmarks on a daily basis, for less than $100 USD I've found a fan that does an amazing job keeping the temperature suitable for all of the running systems.
As I underestimated the cooling requirements when turning a basement into a big Linux server room, for months I've been trying out different economical methods for cooling all of these Linux systems. During the summer months, the air conditioning works fairly well, but the electrical costs soar. Now into the cooler months, it's been a bit more of a challenge to avoid running the air conditioner and cooling the rest of the house... Had I been doing everything over again, I likely would have gone for a split cooling system to keep all of the systems cool.
After experimenting with different cooling contraptions to deploy after the fast and economical, I've found a fan that really makes a huge difference in the cooling potential! A fan that has dropped the average operating temperature by about eight degrees Fahrenheit. It no longer feels like you're walking into a sauna but the temperature is much more comfortable...
This find is the Tjernlund M-6. The Tjernlund M-6 is intended for indoor, hydroponic gardens and for other exhaust purposes. This six-inch inline fan has an airflow rating of 530 cubic feet per minute, which is much greater (more than 2x!) of other duct fans I've tried up to now. 530 CFM should be appropriately sized for the dimensions of the room to have the air frequently circulate.
I came across it on Amazon.com for $90 USD and decided to try it out for its 151 customer reviews, 4.5-star rating. It seems to be mostly used by welders, those running their own indoor gardens, and other industrial purposes, but figured it would do a good job ventilating the server room.
I used the Tjernlund to replace a VenTech duct fan I was using previously that I had positioned in a sump pump closet for pushing warm air from the server room up into the rest of the house and then during the summer months to pull cool air from upstairs down into the basement server room. I explained that original setup in Adding Extra Ventilation To The Basement Linux Server Room.