Ok, I live in Sunny Florida, where the heat is just miserable this time of year. I like to wear hats to keep the sun out of my eyes and also to keep it from beating down on my already-hot head. I remember reading somewhere that about 75% of the heat emanating from a human body is released from the head, and that certainly feels accurate every time I have to take my hat off for a few seconds to let the trapped heat out. So I propose this:
Basically, a wide-brimmed hat with a ring-shaped solar panel around the brim. In the top of the hat, centered above the head, is a fan which is powered by the solar panel. The fan blows straight up, propelling the heat away from your head. By cooling the head (where 75% of body heat goes) you cool the rest of your body as well, thus making for a much more pleasant walk to the store.-- 21 Quest, May 20 2006 Cooling hat http://www.skymall....tion=&pid=102130417this is it as near as I remember [xenzag, May 21 2006] http://lovemygift.c...tyle_cool_hat_.html http://lovemygift.c...tyle_cool_hat_.htmlBraubeaton dug this one out recently. [jutta, May 22 2006] The solar-fan hats that I have seen blow the air onto the forehead.-- baconbrain, May 20 2006 Blowing the air onto the forehead is nice, but that still does nothing for the heat trapped under the hat. The hottest part of the head is naturally going to be the part with hair, so that is the part that needs cooling. Now, a hat that combines both of these would be ideal... but if you're only using one I think the forehead needs less attention than the scalp.-- 21 Quest, May 20 2006 It's a good idea, but..... I saw a hat like this in use in New York about ten years ago. A friend of mine had one. It was styled like a sort of colonial/deerstalker/bush hat, sat high on the head, with an air gap underneath and had a small downward pointing fan that cooled the head. The solar panel was on top. It worked really well, but looked very nerdy. Will try to find a link for it.-- xenzag, May 21 2006 Okay, the way I'm reading this is as a recipe for an instant tonsure. Like... AAAAARGH! MY HAT JUST RIPPED ALL THE HAIR OFF THE TOP OF MY HEAD! (...I'm off to join a monastery now, 'cos no-one will ever find me attractive anymore.)-- m_Al_com, May 21 2006 Bun. The way heat collects between your scalp and the top of an ordinary hat, you'd think hatmakers were designing ovens. I'm in favor of keeping a cool head. Most of the time, anyway.-- SledDog, May 21 2006 so a fan-assisted-oven-hat-- shinobi, May 22 2006 I can envision several ways to improve on the designs others have linked to ... none that would cheapen the price or be more reliable. I particularly do not like the idea of a whirling fan inches from my eyes; note that your eyes don't forgive dust and insects blown into them.-- reensure, May 24 2006 Then have the air intake above the brim. The fan need no blow (or suck) so fast as to drag your hair into itself either; a gentle breeze should be enough to keep the scalp cool. [+]-- BunsenHoneydew, Nov 29 2010 This is an aside but....
// I remember reading somewhere that about 75% of the heat emanating from a human body is released from the head//
This is true only if you are wearing a coat, long heavy trousers, warm boots and socks. In that case, your head represents 75% of the exposed skin.
The head is not particularly radiative. If it were, it would of course be possible to devise an excellent coolant based on powdered heads suspended in oil.-- MaxwellBuchanan, Nov 29 2010 But heat rises and escapes through the top, yes?-- 21 Quest, Nov 29 2010 In an actively pumped system like the human bloodstream? No, not necessarily. It escapes where it can.-- BunsenHoneydew, Dec 06 2010 the actul figure would be hard to break down, but the head DOES expel more heat per area of exposed skin mostly because the blood volume flow is much higher there than say your extremities, and your brain has to stay warm so the thermal delta is always high and constant. Also your neck offers up SLEW of beefy veins and arteries close to the surface.
I can think of another area of the male physique that has a lot of blood flow and a large surface area (on me at least) however a solar powered peener blower might get you in trouble from both the exposure factor and the spinning blades.-- metarinka, Dec 06 2010 Perhaps instead of a fan and solar panel, make a hat with a freezer ice pack built in. Just toss the hat in the freezer to cool it when not in use...-- Newshound, Dec 11 2010 Nah, those are baked, and are unsuited to prolonged outings.-- 21 Quest, Dec 12 2010 random, halfbakery