Solar Thermal Concentration and Collection

NightHawkInLight. 2016. How To Make Parabolic Mirrors From Space Blankets. Video. Retrieved from youtube.com/watch?v=8CLRTa_ocmo.

In this video, we see how an air-tight frame and over-pressure can be used to distort a 'space blanket' into a parabolic(-like) shape. It goes on to show how fibreglass, when applied while the film is under pressure, together with a cylindrical 'former' can be used to help retain this shape once it is removed from the frame.

While interesting, the costs of the fibreglass, resin and the cylindrical former likely add quite significantly to the cost of the reflective film. Perhaps this can be alleviated by bonding the film to an acetate backing sheet and distorting the resulting material under heat, as per Robert Murray-Smith (2022).

Sergiy Yurko. 2022. Its efficiency? The world's cheapest solar heater of Parabolic Dish type. Video. Retrieved from youtube.com/watch?v=FZZlBw9uGRI

In this video, we see how stiff(ish) wires placed on the front side of the concentrator can be used to tension 'space blankets' into a concave reflector. This has the advantage of not requiring, e.g., fibreglass to retain the reflector's shape post-forming, however it does seem to make it harder to achieve the more ideal parabolic shape; this could, perhaps, be ameliorated by, e.g., cutting threads into the ends of the wires and using nuts and washers to make it easier to fine-tune the tension of each wire post-installation. The video also shows the use of a simple mechanism that can be used to keep the target at the reflector's focus, even as the sun tracks through the sky.

Although the measurement methodology is not explained, this video also includes results which suggest a collection / concentration efficiency of ~500W/sqm.

Sergiy Yurko. 2022. This solar energy innovation is 10 times cheaper than analogues: solar electricity 24 hours a day. Video. Retrieved from youtube.com/watch?v=5eKgn_zlOCA.

Robert Murray-Smith. 2022. 1384 How To Make Lenses of any Size or Focal Length Easily and Cheaply. Video. Retrieved from youtube.com/watch?v=YTEZD_Qrw9k.

In this video, a technique is shown that can be used form parabolic(-like) lens shapes out of polyethylene terephthalate (PET/PETE) sheeting using an air-tight former, heat to soften the plastic, and over- or under-pressure to create the actual deformations.

Pairs of the resulting sheeting can be joined and filled with water to create actual lenses (where their curvature / focal-length can be controlled by adjusting the pressure of the partial-vacuum used during the forming process), however, it's also possible that, if the PETE sheeting can be bonded to 'space blankets' using a flexible adhesive, the resulting laminate could be used to vacuum form parabolic reflectors for use in solar-thermal concentrators without the need for the fibreglass backing or wire-grid tensioning used in the above videos.