Linear Fresnel Solar Concentrator
The solar concentrator arrangement proposed for the factor e farm implementation is of the linear fresnel type. Linear, as it's focus is a line as opposed to a point, and fresenl as it is made of many small reflectors as opposed to a monolithic parabolic trough.
This is a discussion of the theory of linear fresnel solar concnetrators, and a justification of the design decisions siezed upon by the factor e farm team.
Estimating available energy
to be added soon. should cover:
1) total insolation 2) air mass losses 3) declination losses
Given an estimate of available energy for a particular day of the year, actual performance estimates can be made, and (once operable) efficiencies measured.
Implementation dependant losses and issues
There a three common orientations:
1) polar 2) North-South axis 3) East-West axis
Each of these three possible orientations has associated tracking issues and also efficency losses specific to that orientation (end losses).
The Polar orientation focuses on a line parallel to the pole of the earths rotation, that is, inclined and running north-south. Tracking here is the simplest, as the mirrors need only rotate at half the angular speed of the earths rotation. However, due to the need to incline the absorber and reflectors, this orientation requires more structural considerations (and expenditures) than a flat (of the ground) approach. Thus, the Factor E farm team has decided against this.
The North-South orientation is similar to the polar orientation, but may be flat on the ground. Tracking may be as simple as in polar or it may have hidden complications (We don't know). Due to the latitude of the Factor E farm, the end losses associated with the shallowness of the suns angle parallel to the axis of the collector would be severe in winter if this orientation were laid flat on the ground. Since we do not wish to tilt the array towards the south for construction cost reasons (same as polar), and wish to collect energy during the winter, The factor E Farm team has shied away from this orientation as well.