Sony is now producing a portable, wearable personal air conditioner. Called the Reon Pocket, it comes with a dedicated undershirt with a pocket sewn below the nape of the neck; the smartphone-sized cooling unit sits in this pocket, and a "heat dissipation mechanism" sucks heat off of your body while a small fan blows it through the back of the shirt.
The wearer can dial the cooling level in using a smartphone app, and there's also an automatic mode that takes advantage of a built-in motion sensor; for instance, the device can detect if you're stationary or walking, and adjust the coolness to suit.
The functionality can also be reversed; the Reon Pocket can be used in winter as a personal heater.
Japanese-market only, at least for now, the device is being sold in retail stores in Japan and on Amazon Japan for ¥18,900 (USD $176).