I would bring a surge protector over a dehumidifier any day of the week. In fact I would go as far as saying you don't need a dehumidifier at all and it's a huge waste of money and space to bring one down. Why do I say that? because all the rooms are air conditioned. Mold is only a problem when they turn everything off during summer and winter breaks, and guess what your dehumidifier won't help you then because it will be packed away in a box.
Surge protectors on the other hand are about twice the price they are in the US and the quality will be much less. Also surges and outages happen at least once a term and so a good surge protector is highly recommended if not required. I would also go as far as bringing a mini-travel surge protector so that you can surge protect your laptop when you're in the library or one of the study areas.
However, something 1000X better than a surge protector is a constant power supply. Because trough's in electricity are more common than surges, and they can do just as much damage to your laptop. I have had two laptops ruined by a trough and know 3 others with the same issues. What happens is the electricity level dips causing your hd to spin slower this causes the needle that's reading the hd to grind into the disk making scratches. These scratches will cause your laptop to run much slower or fail in general. That's why if you look at any computer that's owned by the school you'll see a big box attached to it that box is a constant power supply which delivers a constant flow of electricity to what ever it's hooked up to it thus preventing both surges and troughs. APC makes some great constant power supplies.