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共用题干 Better Solar Energy Systems: More

Loveyou2019-12-17  29
问题 共用题干Better Solar Energy Systems: More Heat, More Light
Solar photovoltaic thermal energy systems,or PVTs,generate both heat and electricity,but until 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,which lets the silicon 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 cost. And it's also a space problem:photovol-taic cells can take 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 engineer-ing,has devised a solution 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.
Most solar panels are made with 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 require much less silicon,they have a greener footprint. Unfortunately,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 expose them to light-pretty much the worst possible effect for a solar cell,"Pearce explains,which is one of the reasons thin-film solar panels make up only a small fraction of the market.
However,Pearce and his team found a way to engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new type 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 point of water,they could make thicker cells that largely overcame the Staebler-Wronski effect. When they applied the thin-fulm silicon directly to a solar thermal en-ergy collector,they also found that by baking the cell once a day,they boosted the solar cell's e-lectrical efficiency by over 10 percent.
选项 PVTs are not efficient in______.A:.creating electricityB: cooling silicon solar cellsC: generating heatD: powering solar thermal collectors
答案C
解析根据第一段“they haven't been very good at the heat-generating part...”可知，与太阳热能单机收集器相比，传统太阳能光伏热能系统在转换热能方面效率不是很高。 根据第二段可知，光电管占去屋顶的所有空间，几乎没有空间留给热能的产出。因此，传统太阳能光伏热能系统存在的一个问题是，占用太多空间，即C选项。文章也提到好的太阳能热水系统比太阳能电力系统成本低得多，但并没有说传统太阳能光伏热能系统贵到人们买不起的程度，因此B项错误。故本题选C。 根据第四段“...but they are lighter , flexible , and cheaper. And , because they requiremuch less silicon , they have a greener footprint.”可知，选项B,C,D在文中都直接提到，A 项没有提到。 根据第五段可知，薄型太阳能板只占有市场的一少部分的原因是，当被暴露在光线下，那就意味着它们的能效会降低——这几乎是太阳能电池最可能糟糕的效应。 通读文章最后一段可知，如果一天把太阳能电池加热一次，那么太阳能的电力效能会增加10%。即A选项正确，其他三项在文中并未提及。
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