An Understanding Of Some Heliostat Concepts

Video Notes:




This shows how a heliostat can also be used to combine all the light rays into a tight focus or concentrated spot of energy (see Fig. 3 where the left (L) side of the mirror has been slightly adjusted). Unlike with a parabolic mirror, the targer/or receiver does not interfere with the collected/refelected light at the mirror, hence the larger the receiver/target the more feasable to use a heliostat rather than a parabolic dish.

In the video I show the left side of the mirror "hard or fixed mounted" to the right side of the mirror in all the figures. Each mirror adds more weight that the motors need to be able to move. Today, there are very thin (1/16 inch thick) mirrors and even highly reflective and lightweight mylar films that can be used for mirrors...these may need some stability from the wind though.

Note that the light rays from the Sun that strike the mirror are nearly parallel, and since the mirror is flat, the light rays that reflect will also be nearly parallel since they will be reflected at the same (angle).

Technically for the (heliostat) mirror to reflect the light of the Sun onto a fixed target/collector/receiver that the face/surface of the mirror is "aimed" at both the horizontal (left to right) and vertical (up and down) angle bisection (half the angle) points between the Sun and the receiver. This is somewhat indicated with the purple line in the video.

It is very feasable, like others have already done, to have "ganged" or mechanically linked mirrors that move as the "main or primary" heliostat mirror moves. But these "secondary" mirrors can have their very own receiver and be easilly set to others, or if needed, even the light can be combined to increase the energy focused onto the receiver.

The closer the Suns rays and reflected rays are on the same line, the more energy collected. As the Sun sets, the less energy collected by the mirror since the length of the effective cross section of the mirror that receives the Sunlight is less. Of course you could adjust/move the target/receivers position so as to remedy this a bit, and if your concentrating the light from several fixed mirrors to a central focus, the receiver will have to be at the same distance (ie. radius) from the primary mirror so that all the light rays from each mirror will intersect at the receiver.

There are several good sites related to heliostats. The field needs new developments and ideas from you. It's not just about heliostats, but about CNC too. Do you know something about gears, heliostats, mirrors, solar things, or stepper motors, etc. Here is a good site and forum that you can join:

http://cerebralmeltdown.com


This video was made by me, however some of the concepts are probably already known to those in the field, so I cant take full credit of all the concepts presented, but are indebted to those who had previously thought about such matters. Some of the great concepts of heliostats first came from using mirrors to communicate (with light and shadow) with over long distances perhaps up to 10 miles or so. This would be the equivalent of a mobile walk-talkie or cellphone today.

Heliostat = helio + stat = Sun + Stationary or Static , where the receiver is the static or stationary part of the system, or: to keep the Sun light in the same position.


(c) trailkeeper on YouTube.com

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