Both types of lenses can be used for solar cooking and boiling water.
|There are three types of Fresnel lenses, linear, spot, and continuous linear. Linear and spot lenses look similar in terms of the circular Fresnel pattern but a spot lens may appear more transparent. Spot lenses produce a very small tight focal pattern at the optimal focal length and are generally more powerful size for size. Linear lenses produce a longer flat focal pattern ranging from 1 inch high by 3 inches wide up to 8 inches wide.
Continuous linear lenses are rarely used for solar and produce a thin flat beam the length of the lens much like a parabolic trough. Optically stable UV inhibitors are required for lenses experiencing solar exposure to the sun or the materials will deteriorate rapidly with sun exposure.
Linear Fresnel Lens Advantages:
Less chance of damaging equipment if liquid evaporates
Long beam can be spread the length of a pipe
Powers a Steam Engine slower but more safely
More opaque due to physical nature, less light (power) transferred to project
Cannot be used for melting metals
Beam NOT continuous Linear like a trough (1" tall x 3" - 6" wide optimal)
Spot Fresnel Lens Advantages:
High power heat transfer (available in Crystal Clear Acrylic perfection cutting)
Can be set to less of a focal length (ideal for cooking)
Melts copper and many other materials
Powers a Sterling Engine and Steam Engine
Instant flame and work hazard
Does not spread over a pipe surface evenly
BUY A HUGE FRESNEL LENS
LINEAR FRESNEL LENS
SPOT FRESNEL LENS