That exact scenario happened to one of my former employers. We installed a server in a closet in this hallway. The hallway had no HVAC and the installation wa

That exact scenario happened to one of my former employers. We installed a server in a closet in this hallway. The hallway had no HVAC and the installation was in the winter (so the hallway was always very cold). I remember asking what we were going to do in the summer. Eventually the summer came around and one morning the server was down. Fortunately there wasn't anything time-critical on the server, everything was backed up both on and off site and we got it up and running again a couple of hours. It turned out that all we needed to do was cut a vent in the door and mount a box-fan to it.