Portable air conditioners are the perfect solution when you need to cool efficiently on the go. Most people think that air conditioners are big and bulky devices, but they really aren't. You can rent a comfortable coolroom which is small enough to fit in a pocket and run on batteries.
There are even accessories you can use to attach portable devices to things. If you prefer not to attach it to anything, you can leave it on your desk or desktop.
For small battery-operated devices, see Frigidaire, Cooper, Fedders, and Sanyo. Remember, upfront costs are not the only cost. You still need to buy a battery for the device to work. If you don't want to continue the charge, look for a solar fan.
If you have the option to run the device on electricity, you have more options. You can also take a room or window. They cool a small area, such as just one room in a house or apartment. Why pay to cool an empty room or a roommate?
This has the advantage of being almost as powerful as a central air unit, but you don't have to pay a lot or worry about air ducts.
If you have a small cold room but you will be staying in it for a while, you can install modules. You can take the one that comes in through the window or mounted on the wall. They are easy to install and easy to upload with brackets.