For many years now solar garden lanterns have been sold. These small lamps feature a small solar cell, a rechargeable battery, at least one light-emitting diode and some simple control electronics. See also my post on a similar project I recently constructed: Lights for the Energy house (to be translated). A couple of years ago almost all these lanterns were fitted with yellow LEDs, but nowadays almost all come with bright white LEDs. Even IKEA is selling several lamps which would fit this description and my personal favorite is Sunnan, featuring a separate battery-pack including the solar cell — charge the battery outdoors during daytime, put it back into the lamp and enjoy the light in the evening. Best of all: together with Unicef IKEA gives away one lamp to developing countries for each sold lamp.
Now a Hongkong based company comes with a brand new invention: a solar powered LED light in the shape of a light bulb. I don’t know why Nokero (pun intended: these lamps really do need no kerosene!) they chose this odd design, but what I understand even less is how two major information sources can make such a fuzz about it: Today Photon international cited a news article from July 18th in Welt online.
The news article is incredible in its incompetence. The author Thomas Jüngling does not seem to have the slightest clue on what he is writing about, when he types:
Dafür bieten sie aber eine weltweite technische Neuheit: Die eingebauten Leuchtdioden (LEDs) strahlen mithilfe von Sonnenkraft.
They offer a worldwide technical novelty: The built-in light-emitting diodes (LEDs) light with the help of solar power.
He then continues
Helligkeit erzeugt es über Kerosinlampen, die lediglich ein Zweihundertstel so viel Strom verbrauchen wie herkömmliche Modelle.
Light is generated by means of kerosene lamps which only consume one twohundredth of the (electric) current compared to conventional models.
I wonder how much current a conventional kerosene lantern actually consumes…
Interestingly enough Welt online does not admit commenting on this article…
Photosynthesis is considered to be 5% effieicnt.1 Solar photovoltaic panels to convert sunlight to electricity that you can buy are from 8 to 22% effieicnt.2 In the lab they have gotten up to 42% efficiency.3 Solar thermal panels used to heat hot water are from 60 to 80% effieicnt.4
With 5% you are overestimating the efficiency of photosynthesis – at least when it comes to available energy output which is technologically useable.
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