Sunday, May 6, 2012

No. 51: Developing other kinds of renewable energy generation systems (2/2) (May 7, 2012)

Technology
Energy harvesting is advancing. The technology to change radio waves from TV broadcasting, mobile phone, wireless LAN to electricity was developed by Nihon Dengyo Kosaku. This technology is called rectifying antenna, or rectenna for short. Catching radio waves in the air makes it possible to generate electricity anywhere. That is, outside equipment with built-in rectenna technology can receive radio waves for power supply. The company plans to put the technology into practical use within the year. Murata Manufacturing, Ceratec Engineering, and Sound Power are developing piezoelectric vibration generation technology that changes pressure and vibration into electricity. That is, a remote controller that incorporates piezoelectric vibration generation technology does not need a battery because it can generate electricity when one of its buttons is pushed.

Kobe Steel launched a binary cycle system that generates electricity using hot spring. The system heats the alternative for chlorofluorocarbon that flows inside the system to boiling through heat exchange. It can boil hot water of 70 degrees centigrade and create steam, and the created steam generates electricity of 70 kW. This output is enough to satisfy the power demand of a hotel. Xenesys has been conducting research on ocean thermal energy conversion for the past more than 10 years. The technology is to run a turbine with steam created by surface water. The created steam is liquefied after it is cooled down with deep ocean water. The principle is the same as binary cycle. Sea areas suitable for thermal energy conversion need to have surface water of 25 degrees centigrade and deep ocean water of 5 degrees centigrade. There are not so many suitable sea areas except off Okinawa Island in Japan, but there are lots of suitable sea areas in the world. The potential amount is estimated at 1,000 billion kW. The company plans to commercialize the technology as the power station for isolated islands. 

Rectenna to harvest terresterial digital broadcasting  
















A sample of piezoelectric vibration generation




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