Polymer-Based Mirror Film Inserts as a Reflective Material in Parabolic Solar Concentrator Applications

The Solar Concentrator has a parabolic reflector which enables to concentrate the sun’s energy into a focal point where the solar collector is positioned. The solar concentrator is equipped with a dual axis celestial tracking system for tracking the sun during its operation

A Technological Objective

To research the possibility to utilize Polymer-Based Mirror Film Inserts (reflective insert is the material which in inserted onto the parabolic dish) as a reflective material in Parabolic Solar Concentrator application with the celestial sun tracking system. The Polymer-Based Mirror Film Inserts will be researched on a standard prime Focus Antenna System which can operate in various climatic conditions (from -20 deg C to 45 deg. C). Currently, the Parabolic Solar Concentrator designs use custom made low iron parabolic glass mirrors. However, this design is very expensive and not available to the average consumer. In addition, the operating cost of the custom made mirrors is very high. The current application of Polymer-Based Mirror Film is only used in parabolic troughs where there is only one curve. The technological objective is to research possible utilization of Polymer-Based Mirror Film Inserts which are curved in both directions in standard Prime Focus Antenna System. This research will allow Polymer-Based Mirror Inserts to be used with Parabolic Concentrator Designs from 1.8 m to 12m diameters.

B. Scientific or Technological Advancement

This scientific research will allow application engineers to implement low cost Polymer-Based Mirror Inserts in Parabolic Solar Concentrators with the celestial sun tracking system and also will increase the knowledge of low cost Solar Energy harvesting process. The celestial sun tracking system in conjunction with Polymer-Based Mirror Inserts will provide a new cost effective solution for energy production. As a result, the researched material will help designers or engineers to create commercially viable Parabolic Solar Concentrators for private, commercial and industrial applications. At present, the Solar Concentrators are:

1. Very Expensive
2. Limited to Utility Applications
3. Requires Supervision
4. High Maintenance Cost

The research consists of investigating the various combinations of substrate and Polymer-Based Mirror Film for parabolic Solar Concentrators to achieve 73-83% energy efficiency in the focal point. Furthermore, the conducted research will potentially find a possible solution to overcome the high cost of manufacturing in the current Solar Concentrator designs. This research will aid in creating scientific knowledge in Harvesting of Solar Energy. As result, the Parabolic Solar Concentrators might be considered as an alternative energy source, which can help to reduce the energy costs. Furthermore, this scientific and technological research will lead to the development of new generation of Parabolic Solar Concentrators to power homes, industries and commercial buildings.

The scientific research will provide the following technological advancements:

1. It will reduce the cost of Parabolic Solar Concentrator
2. It will make solar energy a viable business option
3. It will allow designers/engineers to better understand the solar energy harvesting process

C. Scientific or technological uncertainty

The technological uncertainty is the fact that the Polymer-Based Mirror Film was developed for metal substrate which has only one curve (parabolic troughs). In parabolic concentrator application, Polymer-Based Mirror Film is applied to acrylic substrate and is subjected to a heat during the petal forming process and physical stress occurs due to the bidirectional flexing of Polymer-Based Mirror Film. As result, a potential breakage of the mirror film can occur. Furthermore, the sun’s focal point needs to be investigated to determine whether the Polymer-Based Mirror Film insert can provide uniform sun pattern in the focal point. In addition, the following questions need to be answered: Can various stress relief processes be applied to Polymer-Based Mirror Film to reduce the stress and breakage of the material under diversified climatic conditions? This challenging question creates scientific and technological uncertainty. Various temperature forming concepts need to be researched before it can be concluded that there is a possibility to utilize Polymer-Based Mirror Film as a reflective material in Solar Concentrators. The Polymer-Based Mirror Film must be researched under the following conditions:

• Physical stress
• Thermal stress
• Various weather conditions
• Various temperature conditions (-20 deg. C to 45C deg.)

For example, it was found that the Polymer-Based Mirror Film performed quite well at 20 deg. C; however, the same Polymer-Based Mirror Film experienced peeling off at the edges of the petals at -12 deg. C. It was confirmed that the higher incidents of peeling off occurred under freeze and thaw temperature conditions. In addition, it was noted that the focal point sun pattern is not very uniform. Can a new celestial tracking system with a new collector/absorber design compensate for a non- uniform sun pattern? The appropriate research, testing and evaluation must be studied to analyze the above situation. Therefore, there is great scientific uncertainty regarding the outcome of the research regarding the possibility of using Polymer-Based Mirror Film in Solar concentrator applications. Currently, there is not a single company which commercially manufactures Solar Concentrators made out of Polymer-Based Mirror Film.

Here the author Julia Herniak concludes the article Polymer-Based Mirror Film Inserts as a Reflective Material in Parabolic Solar Concentrator. More information on Solar Concentrators, visit http://www.solartronenergy.com

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