经济学人下载:太阳能 花朵的能量

Science and technology
科学技术

Solar energy
太阳能

Flower power
花朵的能量

In matters of clever design, nature has often got there first
若论巧夺天工，自然常常更胜一筹

A virtuous spiral
上面的螺纹看似简单，实际有效

SOLAR-POWER stations take up a lot of room.
太阳能发电站占地面积巨大，

They need either vast arrays of photovoltaic panels, which convert sunlight directly into electricity, or of mirrors,
站内大部分的空间被光伏太阳能板或和定向反射镜所占据。前者能将光能直接转换为电能；后者会将太阳热折射到锅炉，

which direct it towards a boiler, in order to raise steam and drive a generator.
利用锅炉将水加热成蒸汽，驱动发电机组工作，达到热能转化为电能的目的。

The space these arrays occupy could often be used for other purposes.
这些整齐排列的面板和镜身所占的区域通常能用于其它用途。

Two researchers from the Massachusetts Institute of Technology have now devised a better and more compact way of laying out arrays of mirrors.
麻省理工学院的两位研究员就找出了更好的方法布置定向反射镜排列，不仅能节约出更多的空间，还能提高发电效率。

Slightly to their chagrin, however, and somehow appropriately,
然而，有点儿让他们懊恼的是，

they found when they had done the calculations that sunflowers had got there first.
他们计算出的和向日葵花盘型花序上所排列的，大致相同。

Alexander Mitsos and Corey Noone started with the observation that existing concentrated solar-power plants,
Alexander Mitsos和Corey Noone这两位研究员先从观察运行中的集中型太阳能发电厂入手。

as those which drive boilers are known, usually have their mirrors arranged in a way that resembles the seating in a cinema.
如大家所知，这些发电厂用太阳能驱动锅炉做功产生热量。通常定向反射镜的安排布置与电影院座椅位置如出一辙。

The mirrors are placed in concentric semicircles facing a tower, on top of which the boiler and the turbine sit.
高塔处于荧屏所在的中心位置，所有的定向反射镜则以高塔为圆心，呈半圆形分布。

That arrangement, however, sometimes results in the mirrors shading each other as the sun's position in the sky changes,
随着一天中太阳在天空中位置的变换，镜身间会出现相互遮挡的问题。

even though the mirrors are usually attached to robotic arms that track the sun as it moves.
即使厂家通常会在镜身后部安装能随太阳位置变换而相应变换的机械手臂，但这一问题还是无法解决。

According to their report in Solar Energy, Dr Mitsos and Mr Noone found that they could do better.
据他们在《太阳能》杂志上发表的文章称，两位研究员认为能有方法解决这一难题。

They divided each of the mirrors in a real power plant, PS10, in southern Spain into about 100 pieces.
在一家位于西班牙南部的发电站，PS10中，他们把每一片定向反射镜的平面面积分为差不多100块。

They then plugged each of those pieces into a computer model that calculated all of the energy losses
然后将每一片镜身上的这100多块面积里产生的吸热数据接入电脑，通过电脑程序计算出能量损失总和。

by noting points where mirrors were not optimally oriented to the sun and places where they hindered one another by blocking incoming or reflected rays.
这包括镜身没能直对太阳造成的损失，以及镜身位置因相互遮挡使折射光线受阻或反射到锅炉的光线受阻时造成的损失。

It then rejigged them into a better arrangement.
然后再根据数据重新对镜身进行排列组合。

Fermat's conjecture
费马螺线魔力

Previous efforts have been directed mainly at stopping the mirrors shading each other, which tends to mean spreading them out.
在此之前，人们做出了种种努力，但总是在镜身相互遮挡这一问题上束手无策。而对此常会采用的是展开布局，增加排列面积来避免这种情况出现。

Dr Mitsos and Mr Noone also wanted to save space.
而两位研究员还想节省面积。

In trying to do so they stumbled on an unusual arrangement that had the desired effect.
为此绞尽脑汁之际，他们无意中发现有一种非常规的排列布局有很好的效果。

When they showed this layout to a third researcher, Manuel Torrilhon of Aachen University in Germany,
他们将这种布局安排展示给另一位研究者，德国亚琛工业大学的Manuel Torrilhon。

he recognised the spiral patterns within it, and this prompted the trio to test a design specifically modelled on nature.
后者认为这种设计中有螺线存在，这促使三位研究者以向日葵花盘型花序为蓝本仔细测试设计。

That design was a pattern known as a Fermat spiral, in which each element is set at a constant angle of 137° to the previous one.
他们采用的设计即费马螺线。即每一个圆在之前一个圆旋转角度为137度时，折线回旋螺线。

It is most familiar as the arrangement of the florets that make up a sunflower head.
这一排列布置与向日葵花的盘型花序纹路如出一辙。

When the three researchers programmed their model to arrange PS10's mirrors in front of the tower in a segment from such a spiral,
三位研究者按照计划安排PS10发电厂的镜身位置，在高塔前，将定向反射镜呈部分费马螺线状布局。

they both improved the efficiency of the collection process and saved space.
结果显示在吸收太阳热量的过程中，效率得以提高，占地面积减少。

The improvement in efficiency was, admittedly, quite small,
诚然，效率提高非常有限，

but the space saving was significant—almost 16%.
而空间节省面积却很高，减少近16%。

If solar power is to make up much of the world's electricity output in future, as supporters of alternative energy hope it will,
如果太阳能如可替代能源支持者所希望的一那样，在未来成为世界电力的重要来源，

a lot of land will be needed for the power stations.
那么太阳能发电站势必将需要占据更大的面积。

Reducing that requirement by a sixth, as this discovery promises, would be a big gain.
如果能像此次研究所发现的那样，有希望将定向反射镜所占地面积减少六分之一，那么这将是一个巨大的进步。

It would also show that if you look hard enough, there really is nothing new under the sun.
同样让我们认识到的是，地球上还有许多未知等待我们认真研究。