Cooling off a hot room requires replacing the hot air with cooler air. Since a fan just blows the air around without changing its temperature, you must change the temperature of the air that is being blown in some way. To make a battery-powered fan able to blow colder air, acquire supplies from a grocery store and from a kitchen supply store. The procedure is straightforward and is renewable. No additional electricity will be used.
Fill three empty plastic bottles nearly to the top with tap water. Stand the three bottles in the freezer section of your refrigerator. Leave the bottles in the freezer overnight to freeze.
Place the plastic bowl on the table, in front of the fan which is also standing on the table. Let 10 minutes pass before continuing.
Turn the fan on. Stand in front of the bowl, opposite the fan, to enjoy the cooling breeze from the fan as it blows the colder air being generated by the condensation of the ice in the bottles melting.