A Better Focus Co.
Questions and Answers
These dishes and tracking frame looks reminiscent of the "Dish/Engine"
systems that have been developed in years past. How does your system
First, A Better Focus Co. does not utilize a Sterling or other type of heat engine
for directly generating electricity from the sun's heat. Our system is intended to
heat water/steam for use either in a process, or to run a traditional
turbine/generator set. This can be termed a Dish/Thermal system.
Secondly, our concentrating dishes utilize reflective film instead of glass mirrors,
providing reflective performance superior to most mirrors, and at a fraction of the
cost and weight. Lighter dishes also mean much lighter tracking frames may be
Lastly, most dish/engine systems are configured as a single unit, with an engine
required for each tracking frame. While we could also utilize an integral boiler for
each of our tracking frames, we prefer a mini "power tower" approach, whereby
many 4-dish trackers can focus onto the top of a stationary tower, which would
house a single boiler sized for the total incoming solar energy.
Why implement the system with round dishes vs. the more common
The "point focus" of a dish system experiences less radiant losses at the surface
that receives the concentrated energy than the long tube that receives the heat in
a "line focus" trough. Point focus systems do require two-axis tracking to keep the
small hot spot of focused light on the intended target, however. Trough systems
typically utilize only single axis tracking.
How can plastic film last as long as glass?
While glass provides the hardest of surfaces, it is not without it's own problems,
such as pitting, breakage, and tunnelling.
A Better Focus Co. is not directly involved in the research of polymeric reflective
materials, but we have been very happy with the durability of the materials we
have tested over the past 5 years. Below is a link to an NREL summary paper on
the subject, and also to Reflectech Solar Inc., one of the better suppliers.
National Renewable Energy Lab Report
ReflecTech Solar Inc.
Remember when people used to chuckle at the increasing use of "cheap" plastic
in automobiles? The content has done nothing but increase over the years.
Most automobiles are now successfully using plastic vs. glass for headlight
reflectors, lenses, and for other optical applications
While it's true that polymeric materials have gained wide acceptance in a
wide array of applications, a solar concentrating system requires many
hundreds of square feet of reflective surface to be feasible. How can
these lightweight dishes and it's tracking system endure high winds?
We've designed an innovative stowage method whereby the tracking frame
weathervanes away from oncoming winds of over 30 MPH. The large dishes flip
upward in the wind, reducing the area incident to the oncoming wind by more than
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