Ah, the ceiling fan. My closest companion on hot summer days, my savior from the everlasting, unrelenting heat. To imagine a summer without one would be to imagine everlasting pain, torture, and death. All jokes aside, fans are something we take for granted. Have you ever wondered how these devices can keep us cool for so long?
Well, first we should take a look at how ceiling fans actually operate.
Essentially, the motor (which runs on electricity) creates an electrical current which passes through coils wrapped around the motor. The current creates a magnetic field, which changes the energy into kinetic energy. The coils start to spin, which causes the fan blades to move.
During this process, the overall temperature isn’t actually decreasing—it’s increasing. The motor gives off small amounts of heat, which heat up the area it is in. But the rotation of the blades must be cooling down the room, right? Sadly, that’s not how heat works. Heat is the movement of energy between objects, and your fan’s blades spinning aren’t going to affect heat that much.
So how does your fan cool down your body? It is all due to the wind chill effect. The main way your body loses heat is perspiration or sweat. Your fan blows the air around your body around you, which allows the air to pick up and evaporate your sweat quicker, which allows you to sweat more, so you lose more heat. The only thing the fan is cooling is you, and it doesn’t affect the temperature in your room. Nonetheless, I’m still grateful for my fan for evaporating my sweat faster. :)