Which is better for concentrating sunlight ?

[anjanamurthy]

which is better for concentrating sunlight ??

I m doing a project on solar illumination . I wanted to know which configuration of parabolic reflector/ collector is better in terms of efficiency - central axis (cassegrain) or off axis ??

 

[sophiecentaur]

For a simple solar reflector where no high quality image is required, it's largely down to the effective area of the reflector. This may be reduced for an off axis reflector by a small amount due to the projection turning a circle into an ellipse, with a slightly smaller area - but the Cassegrain system 'wastes' all that central area for the secondary reflector.

 

[anjanamurthy]

Well this is for a direct solar illumination project which requires tracking of sun. So if we consider that also .. which of the two would be better ??
In terms of tracking accuracy required and feasibility to track ...

 

[DaveC426913]

Well this is for a direct solar illumination project which requires tracking of sun. So if we consider that also .. which of the two would be better ??
In terms of tracking accuracy required and feasibility to track ...

What are your thoughts on reasons why one might be better over the other?

 

[sophiecentaur]

Well this is for a direct solar illumination project which requires tracking of sun. So if we consider that also .. which of the two would be better ??
In terms of tracking accuracy required and feasibility to track ...

How well does need it to track? What size object do you want to concentrate the sunlight on? How much power do you want? (a few Watts or several kW?)
So far it's 'how long is a piece of string?'