I live in a basement unit in an old building. There are steam pipes that are running through above my ceiling and these are what's causing the excess heat. Because it's an old building, I'm sure the insulation on these pipes has been degraded. There is a closet in my unit that has the most concentrated heat. Is there some temporary fix (until the insulation of the pipes is checked) to divert the heat to some other location or if there's some sort of heat sink?
This is a very common problem in old steam heated buildings. They get too hot or too cold. Your only option as a renter is to open windows or use vent fans if you have them. I would contact your landlord or management company and see what they have to say. Perhaps they have a solution. You can also talk to your super and see if they have any tips or tricks. Otherwise you are stuck with your situation. A removable window fan with louvers and thermostat would be a simple automatic solution.
Second, when you say steam pipes in an old building I picture old asbestos covered pipes. Don't mess with those, EVER! Asbestos doesn't really degrade and neither does fiberglass provided there is no water damage. If I were you, I'd look for another apartment if you have asbestos. You could be living in a health hazard if the asbestos wasn't removed (and it rarely is as the cost is enormous).