Buy a window unit, put it on a roll around cart, aim it towards you. Put it in a corner when not in use.
This does not work, and will actually make it hotter. They produce more heat than cool, due to not being %100 efficient, plus use causes heat. There is no free lunch here, the heat must be vented.
On the other hand, they DO make portable air conditioners that have a hose exhaust to a window insert. (My inlaws have several) they are used only when needed, and roll off into a closet when not needed.
