Better Solar Energy Systems: More Heat, More Light
Solar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but (1) now they haven’t been very good at the heat-generating part compared to a stand-alone solar thermal collector. That’s because they operate at low temperatures to cool crystalline silicon solar cells, (2) lets the silicon羊羔疯有哪些前期症状表现 generate more electricity but isn’t a very efficient way to gather heat.
That’s a problem of economics. Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower (3) . And it’s also a space problem: photovoltaic cells can (4) up all the space on the roof, leaving little room for thermal applications.
In a pair of studies, Joshua Pearce, an associate professor of materials science and engineering, has devised a (5) in the form of a better PVT made with a different kind of silicon. His research collaborators are Kunal Girotra from Thin Silicon in California and Michael Pathak and Stephen Harrison from Queen’s University, Canada.
邢台羊癫疯手术治疗Most solar panels are made (6) crystalline silicon, but you can also make solar cells out of amorphous silicon, commonly known as thin-film silicon. They don’t create as much electricity, but they are lighter, flexible, and cheaper. And, because they (7) much less silicon, they have a greener footprint. (8) , thin-film silicon solar cells are vulnerable to some bad-news physics in the form of the Staebler-Wronski effect.
“That means that their efficiency drops when you (9) them to light―pretty much the worst possible effect for a solar cell,” Pearce explains, which is one of the (10) thin-film solar panels make up only a small fraction of the market.
However, Pearce and his team found a (11) t抗癫痫药物需服用多久o engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new (12) of PVT. You don’t have to cool down thin-film silicon to make it work. In fact, Pearce’s group discovered that by heating it to solar-thermal operating temperatures, near the boiling (13) of water, they could make thicker cells that largely (14) the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy collector, they also found that by baking the cell once a day, they (15) the solar cell’s electrical efficiency by over 10 percent.
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5. A. decision B. suggestion C. qualification D. solution
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8. A. certainly B. luckily C. unfortunately D. immediately
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15. A. defined B. wasted C. lowered D. boosted
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