Tuesday, November 18, 2008

GBW: IKEA cometh to Brooklyn



I have a hate/love/(hate again) relationship with IKEA. I hate the light-birch color of their furniture, because it reminds me of the flesh in a freshly-axed tree, which makes me feel guilty. I love IKEA because it has supplied me with almost all of my furniture (mostly via craigslist). And I hate IKEA again because the entire store is set up to make customers disoriented and lost, so that they come back to the same sections over and over until they decide to buy the merchandise they didn’t think they wanted, like trick answers on a multiple-choice test.

That said, many of our city-dwelling, carless lives have been eased significantly by the opening of an IKEA in Brooklyn this past June. And although it’s located in transportationally-challenged Red Hook, IKEA makes itself accessible to visitors with free shuttles from the F and G trains, a free water taxi to Manhattan, and direct service on two Brooklyn bus lines. In addition, you can rent a UHAUL right out of the parking garage to drive large purchases home.

The Brooklyn IKEA is also pleading its case as a social/environmentally responsible superstore by applying for a silver LEED certificate. The most significant green feature of IKEA is the huge photovoltaic array on its roof, which provides the building with somewhere between 5 and 10 percent of its energy needs.

Put simply, photovoltaic cells work by converting light (photo) energy into electric (voltaic) energy. Although it seems like people are talking about “solar energy” as a relatively new idea, the roots of photovoltaic (PV) technology goes back about 170 years to a French physicist named Alexandre Edmond Becquerel. Becquerel was the first to observe (or at least get credit for observing) that electricity could be created by shining light on to certain chemical solutions. One century and several brilliant minds later, Bell Labs introduced the first high-powered PV silicon cell, and the NY Times predicted that solar cells would lead to a source of “limitless energy” (If I had a nickel for every time...).

PV technology is not only pretty old, but it’s also fairly ubiquitous. Unless you went to school before the 1980’s, your first memory of PV cells probably dates back to your first calculator. And unless you were an exceptionally engaged student, you probably spent some time in math class covering the light sensor with your finger and watching the numbers fade gradually from the display screen, only to reappear when your finger was removed. Voila-- your first tactile experience with semiconductors!

A photovoltaic cell works by using a semiconductor—a material that has some qualities of an insulator and some qualities of a conductor. The most common semiconductor is silicon. In it’s pure state, silicon is stable, meaning that it has neither too many nor too few electrons. However, another trace element can be added to silicon to disturb this balance. This process is called doping, and people use it to create sheets of negatively-charged (n) and positively-charged (p) silicon.

To create a PV cell, the two sheets of semiconductor-- one with extra electrons (n-silicon) and one missing electrons (p-silicon)-- are placed together. When the sun's energy, in the form of photons, strikes the negatively-charged layer, electrons are knocked loose and move toward the p-silicon. This movement of electons creates an electric field, generating electricity.

4 comments:

Anonymous said...

What happens to the electrons after they arrive at the "p" sheet? Do they travel out the "hole" flow into the atmosphere or do they return to the "n" sheet?

Anonymous said...

hm yeah. why doesn't the n sheet run out of electrons? is the supply replenished by the photons?

Emily said...

thanks for the questions...
i see that a more detailed account of solar cells is in order! i'll try for something more thorough tomorrow.

Anonymous said...

Also, how does this connect back to the Ikea in Redhook?

Great start though!

(Chioke)