Monday, August 03. 2009
Ever since we assembled a 1.6 MW solar panel installation at our headquarters in Mountain View in 2007, we've been wondering, "Does cleaning the solar panels make them more effective?" We thought it might, but we needed to be sure. So we analyzed the mountains of data that we collect about the energy that these panels produce — after rain, after cleaning and at different times of the year.
We have two different sets of solar panels on our campus — completely flat ones installed on carports, and rooftop ones that are tilted.
Since the carport solar panels have no tilt, rain doesn't do a good job of rinsing off the dirt they collect. (Also, our carports are situated across from a sand field, which doesn't help the situation.) We cleaned these panels for the first time after they had been in operation for 15 months, and their energy output doubled overnight. When we cleaned them again eight months later, their output instantly increased by 36 percent. In fact, we found that cleaning these panels is the #1 way to maximize the energy they produce. As a result, we've added the carport solar panels to our spring cleaning checklist.
The rooftop solar panels are a different story. Our data indicates that rain does a sufficient job of cleaning the tilted solar panels. Some dirt does accumulate in the corners, but the resulting reduction in energy output is fairly small — and cleaning tilted panels does not significantly increase their energy production. So for now, we'll let Mother Nature take care of cleaning our rooftop panels.
Accumulated dirt in the corners of a rooftop solar panel
We've also been crunching numbers on dollars-and-cents; the more energy our panels produce, the sooner we'll be paid back by our solar investment. Our analysis now predicts that Google's system will pay for itself in about six and a half years, which is even better than we initially expected.
If you want to learn more about our solar study, check out these slides showing the effects that seasonality, tilt, dirt, particulate matter, rain and cleaning have on Google's solar energy output. We hope you solar panel owners out there can tailor our analysis to the specifics of your own installation to produce some extra energy of your own!
Posted by Winnie Lam, Senior Product Manager
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Via The Official Google Blog
Personal comment:
Logique... Mais cqfd!
It’s no secret that MySpace, once the undisputed leader in the social networking realm, has been losing users at an alarming rate. Hitwise recently reported that the site is sliding in the music and entertainment category, while one proposed comeback strategy includes becoming the leader in online gaming. Others maintain that music is where MySpace began, and returning to its roots could prompt a turnaround in its fortunes (see Can MySpace Make a Comeback?).
In a video posted last week, video site College Humor proposes a less orthodox plan for user retention: it heralds the launch of “MySpace Graveyard”, a place for dead MySpace accounts. “The strategy is simple: as MySpace loses traffic, MySpace Graveyard gains traffic”, says a faux spokesman in the parody clip.
What would convince you to return to MySpace? Let us know in the comments.
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Via Mashable
Personal comment:
Une plaisanterie bien sûr, mais en rapport au post que j'avais publié il y a quelques temps en rapport au décès "futur" de tout ces utilisateurs de réseaux sociaux. Que deviendront leur(s) compte(s)?
A ce jour, le seul projet à ma connaissance qui traite de la mort et des données d'utilisateurs est un projet d'artistes et il s'agit des suisses d'etoy (de notre ami Zai, ancien professeur à l'ECAL).
Studio Lindfors, who previously proposed blimps as an inflatable emergency extension of the metropolis for the What if New York City… design competition, speculate further about the inhabitation of the air in their entry to [bracket], “Cloud Skippers”:
Imagine a community of adventurous pioneers who leave the Earth’s surface to drift and glide amongst the clouds in machine-like dwellings, self-sufficient and free from trappings of everyday life as we know it…
Staying afloat requires work. A delicate equilibrium must be maintained to remain anchored in the air. Abrupt shifts in weight can dislodge a Cloud Skipper from the jet stream - low levels of rainwater storage or sloppy waste management, excessive hoarding or rapid shifts in population - any dramatic change may result in a loss of altitude, or worse, a precipitous fall to Earth. The unique emphasis on weight shapes a new economy with its own values and currency. Gravity banks deal in kilos of crops, or gallons of water, in lieu of more traditional monetary loans. As material over-consumption may have catastrophic consequences, money as we know it is redefined.
Cloud Skippers must also take into account the constant shifting of the jet stream’s course. With no solid connection to the ground below, the idea of community is re-imagined. Assuming a nomadic nature, Cloud Skippers fly whichever way the winds take them. Through such trials and demands, a strong, fluid bond develops among Skippers in their efforts to survive in such a precarious environment. Balance is emphasized, manifested in a collective responsibility of the entire community and reinforced by personal discipline as well as respect for the limits of one’s environment and the needs of one’s neighbors.
That, of course, is the utopian version. There are other possibilities, perhaps no less fascinating, but certainly not as pleasantly communal, as might be suggested by the history of earth-bound nomadic peoples (the near-constant struggle between the Tuareg and whatever governments claim their portions of the Sahara at any given time, for instance). Terrestial governments might not be so willing to cede their airspace or rain to the Cloud Skippers, while the tight communal discipline required to eek out existence in the harsh environment of the jet stream could as easily lead to clannish fragmentation as to a heightened sense of responsibility towards neighbors.
[see also mammoth's own sloppily documented entry to [bracket], which suggests harnessing the wind in a completely different fashion]
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Via Mammoth
[Lake Berryessa, the Monticello Dam, and the largest drain, or spillway, in the world.]
Prompted by an excellent text entitled “Three Doors to Other Worlds” by Andrew Crompton in the JAE from last November, we are following him down the rabbit hole. (Get the complete PDF here.) Crompton positions architecture within the cognitive sciences with a fancy for the grotesque / Baroque. In this particular text Crompton is seeking to chart and qualify architectures that elude description through drawing or photograph, instead requiring something more, err, cognitive. A tall order, and possibly one that were it actually taken to task would be a very short list in architecture, though maybe longer in art and media, and surprisingly engineering. One case in point in Crompton’s search is the architectural equivalent of a black hole. It is a bellmouth spillway. In particular Crompton refers to the Ladybower bellmouth constructed in 1935 near Sheffield, UK.
[The spillway at the Monticello Dam, near San Francisco, CA.]
Unable to evaluate whether the bellmouth truly qualifies for its ineffable status having not seen them in person, it is easy to note in photograph the surreal nature by which the weighty mass of water at once appears as a single surface folding in on itself. Or as Crompton writes: It is easy to overlook its obvious purpose and see instead an object of sinister artistry. Simply speaking, the spillway is a massive drain for the reservoir. It prevents water from rising above a certain level and spilling over the dam or lake shoreline. The bellmouth at the Monticello Dam is the largest in the world at a diameter of 87 feet narrowing to 27 feet and can drain off 367,500 US Gallons per second. Gulp.
Spillways serve to regulate reservoir levels and maintain two states; (1) in use they disappear and are minimally obscured by flowing water, (2) not in use they are sculptural oddities hovering ambiguously above the water line. In use the spillway is pure negative space, a void; not in use, they are solid, positive space. Aside from Crompton’s observations on the black hole condition, we would add the potential for contradictory phase change to its ineffability. The spillway swallows its own description as it imbibes water through Klein-bottle-like inversions.
[Section of the Morning Glory Spillway of the Val Noci Dam in Montoggio, Italy showing revisions made to the design for increased performance.]
The nomenclature behind the bellmouth spillways further its reading as a massive engineered earthen orifice. The mouth, the throat, the shaft. In refining the engineering behind the bellmouth for the Val Noci Dam in Montoggio, Italy a throttle and air supply was added to accelerate the spillways ability to process extreme flow and turn a 90 degree corner. In other words, to keep the bellmouth from choking on itself in grew a tongue.
[Studies of the flow for the Morning Glory spillway for Val Noci Dam.]
[The massive High Island Reservoir, created in 1978 near Hong Kong on the Sai Kung Peninsula, is serviced by this bellmouth.]
[The steeped edges of the Ladybower bellmouth prevent the surficial reading found in the smooth flow of the bellmouth at Monticello Dam.]
[Peering into the ineffable, the Ladybower bellmouth spillway.]
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Via InfraNet Lab
The lost Roman city of Altinum has been found in Italy. Sophisticated aerial images released this week reveal fascinating new details about Venice's predecessor, which was abandoned by its citizens and then sank into the lagoon.
After a long search, the ancient city of Altinum -- considered to be the predecessor of Venice -- has been discovered. In a report published this week in Science, archaeologists at the University of Padua also report that the most popular of Venetian tourist attractions, the Grand Canal, was flowing through the Roman trade town as long as 1,500 years ago.
Altinum plays a major role in Venice's history -- it was one of the richest Roman settlements but inhabitants fled before the advance of the armies of Attila the Hun. Then as water levels rose, the abandoned city sank into the lagoon. Its walls remain covered by fields today. And this is why the ancient city has remained undiscovered for such a long time.
On a modern map, Altinum is situated seven kilometers north of Venice, near the Marco Polo airport. It is the only large Roman city in northern Italy and one of the few in Europe that was not buried beneath medieval or modern towns.
The team of researchers, led by Andrea Ninfo, mapped the city in detail using aerial photography. They also used pictures taken in conjunction with a variety of infra-red filters. During a particularly dry period in the summer of 2007, when plants were stressed and more stonework appeared, the outlines of buildings in the ancient city became more visible. "Everything is just as it was. When we saw the picture we couldn't believe it," Italian archaeologist and co-author of the paper Alessandro Fontana, told Times of London.
According to archaeologists, Venice's ancestor was surrounded by rivers and canals, including one large canal that ran through the center of the city and connected it with the lagoon.
A digital reconstruction of the area shows that the city stood two to three meters above what was then the sea level. The structure of Altinum was complex and perfectly suited to the particular demands of the swampy environment. Researchers say that it looks like the Romans knew how best to build on this harsh, swampy landscape -- long before they began the construction of Venice in the middle of a lagoon.
ecb -- with wires
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Via Der Spiegel
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