Inventing things has to be one of the hardest way to make a living. Once an inventor comes up with an idea for an invention, one often has to think about questions such as "what should the design be like", "how practical is it going to be", "how much it costs to build one", "should I tell anyone about this invention" (no unless the idea is shown only to those who are very tight-lipped). Then the inventor needs to devote a lot of time and possibly money to make one's concept a reality. Of course, an inventor's worst nightmare — someone else had came up with the same idea and the prodcut had already been patented — is always on the inventor's mind. While coming up with a potential invention is quite easy, making that a reality can be quite a challenge.
On one hot day, a chat during lunchtime quickly became a discussion about how to make oneself cool while outdoors in the summer months. During the conversation, someone mentioned that clothing with a built-in fan or air-conidtioning system may be one way to go.
There are many places where the temperature is over 30 degrees for large parts of a year, so if such clothing can be invented, it can be a best-seller. However, as we continued to chat, it quickly became clear that such clothing is much harder to invent (if we were not convinced earlier).
Firstly, there is the matter of where to attach the fan to the clothing without injuring the wearer. Even if the clothing is loose-fitting, there would be many places where the clothing would come in contact with the wearer's skin. So the blades have to be millimetres in length, but then we would have to put in multiple fans as a single fan may not be enough to cool the air. Then there is the matter of the material used to make the blades — even if the blades are made of smooth, dull material, it is not guaranteed that the blades will never bruise the wearer. In a world where slight flaws can lead to million-dollar lawsuits, fans have to be designed so that they will never injure the wearer, if it is possible at all.
The fans won't turn on their own, so the inventor would have to find a way to get the fans spinning. One may harness the power of wind to keep the fans turning, but the wind itself may provide the cooling effect the wearer desires and the fans would not be needed then.
Perhaps the fans can run on batteries, one may say, but the batteries can weigh down the wearer, and most people prefer to wear light clothing in hot days. Besides, we all know what may happen when we put batteries in water containing minerals, like sweat. The wearer may find what happens then shocking.
"What about kinetic enegry?" one may ask. The clothing can use the heat generated by the wearer to power the fans, but that would mean the wearer has to warm oneself up before the blades will turn and to keep oneself hot in order to keep the fans spinning.
With so many obstacles in making such a clothing, I guess we won't find any clothing with built-in electricity-powered fans anytime soon.