...
未读,2010年2月25日 17:50:062010/2/25登录即可回复作者
登录即可转发
您无权在此群组中删除帖子
请登录以举报消息
要么此群组的电子邮件地址为匿名状态,要么您得查看成员电子邮件地址权限才能查看原始帖子
收件人 solar-...@googlegroups.com
A parabolic reflector is imaging, it makes in image of the sun on the
target. Non-imaging concentrators channel radiation without preserving
the relationships between rays which constitute an image. for a given
source, a non-imaging concentrator is Pi times more effective. They
can be designed to not track, track seasonally, or track sloppily.
(with imaging concentrators you design for perfect conditions and get
what you get in the real world).
The complication is that the reflector geometry is more complicated. So, a trade off is having an imaging primary with a non imaging secondary, designed to accommodate the angular uncertainty of the imperfectly tracking primary.
CPC (compound parabolic concentrators) were the first along these lines. More recently, the snail and helmet concentrator.