Matching energy scales in harvesting and computing

Energy Harvesting

• 5G Health limit Does 5G pose health risks? (part 1)

The maximum exposure permitted by the FCC is 1.0 mW/cm² for frequencies between 1.5 GHz and 100 GHz, assuming a 30-minute exposure time. According to Infineon, a 24 GHz system operating at maximum radiated power 5 cm from the skin has a power density of 0.3 mW/cm², one-third of the FCC limit and 15 times below significant thermal heating.

• Cell phones are limited to an equivalent isotropic radiated power (EIRP) output of 3 watts

• RF EXPOSURE FROM MOBILE PHONES, TOWERS, WIFI, AND OTHER RF

What are government safety standards for RF exposure? Different countries have different standards and it also depends on the frequency and length of time of exposure. In the USA the limit for RF power exposure of the public (averaged over 30 minutes) is:
2 W/m^2 (=2 million uW/m^2) at frequencies of 100 MHz to 400 MHz
2 to 10 W/m^2 (=2 million to 10 million uW/m^2) at frequencies of 400 MHz to 2000 MHz
10 W/m^2 (=10 million uW/m^2) at frequencies of 2000 MHz to 5000 MHz.

• At about a meter, we're receiving over 6 watts of power, and at two meters we're talking about a few watts, 2 to 3 watts
  Wireless Power Is Coming Companies like Energous and Ossia are developing 'true' wireless charging that works over the air so you can power up at a distance. But don't throw away your charging cable just yet.

• "Average over the entire earth" of "164 Watts per square meter over a 24 hour day" SUNLIGHT

• the current device can theoretically generate almost 4 watts per square meter Experimental device generates electricity from the coldness of the universe

By comparison, today's solar panels generate 100 to 200 watts per square meter.

dBm to watts conversion

Computing Energy

• check out assisted GPS computing power in early days of GPS

• about power consumption 100W (multiply by hours usage) for a powerful PC (screen+chip)

transmission versus computing

... The chief constraint is wireless data transmission, which uses much more energy than data processing. “But things are improving...

Fake or true?

Compare
a) 100W/m^2 x 50cm^2 x 24h = 12 Wh/day energy harvested if in the sun
b) 5Wh/day see here energy consumed
too close if most of the time inside????

this 4,500 USD solar-powered iPhone the future of business smartphones?

A Russian company called Caviar offers the iPhone X Tesla, which can be charged by just a little sunlight.