In photovoltaic power plants, building lighting, greenhouses, and other applications, the sunlight reflector sheet plays a crucial role as "light regulators." Its core function is to efficiently reflect sunlight, improving energy efficiency or optimizing the lighting environment. The quality of the reflection depends primarily on the choice of materials.
When selecting solar reflector materials, one cannot focus solely on the "reflectivity" indicator. It is necessary to comprehensively consider three core factors: reflectivity stability, environmental adaptability, and mechanical strength. Specifically, these can be broken down into the following dimensions:
High and Stable Reflectivity: This is a fundamental requirement. High-quality materials should have a reflectivity of over 85% for sunlight (especially visible and near-infrared light) and should not easily decrease in reflectivity due to oxidation or corrosion over long-term use—if the reflectivity decreases year by year, it will directly reduce the energy conversion efficiency or light utilization effect of the equipment.
Weather Resistance and Corrosion Resistance: Solar reflectors are mostly used outdoors and must withstand complex environments such as high temperatures, rain, snow, ultraviolet radiation, and humidity changes. Materials must be resistant to UV aging, acid rain corrosion, and high-temperature deformation to avoid problems such as coating peeling and substrate corrosion.
A balance between lightweight and mechanical strength is crucial: reflectors are often installed on supports or building surfaces. Excessively heavy materials increase the load on the supporting structure, posing safety hazards; however, excessively lightweight materials, if lacking strength, are easily deformed and damaged by wind. Therefore, a balance must be found between lightweight and impact and bending resistance.
Considering these requirements, metal sheet (especially aluminum) has become the mainstream choice for sun reflectors—compared to glass (heavy and fragile) and plastic (poor weather resistance and prone to aging), aluminum sheets offer both high reflectivity and excellent weather resistance and lightweight advantages.
Mirror aluminum sheets are produced through a rolling and polishing process, giving the surface of aluminum sheets a mirror-like effect. With a reflectivity of 90%-95%, it boasts the highest reflectivity of all aluminum sheet types, making it particularly suitable for applications requiring extremely high light utilization (such as photovoltaic concentrators and high-precision optical equipment). Its core characteristics include:
High reflectivity: It precisely reflects sunlight with virtually no diffuse reflection loss, ideal for applications requiring directional light concentration;
Smooth and easy-to-clean surface: The mirror structure resists dust accumulation, and rainwater can easily clean it, reducing maintenance costs;
Cautions: Relatively weak scratch resistance; avoid impacts from hard objects during installation and use. More suitable for indoor installations or outdoor applications with protective casings.
Anodized aluminum sheets are produced through an electrolytic process that forms an oxide film (typically 5-20 μm thick) on the surface of an aluminum sheet. This oxide film not only improves reflectivity (approximately 80%-85%) but also significantly enhances the aluminum sheet's corrosion and UV resistance, making it the "preferred material" for harsh outdoor environments (such as building exterior wall reflectors and outdoor greenhouse reflector systems). Its core characteristics include:
Extremely strong weather resistance: The oxide film can withstand acid rain, high temperatures, and UV exposure, with a service life of 15-20 years, far exceeding that of ordinary aluminum sheets;
High mechanical strength: The oxide film enhances the uv reflective aluminum sheet's resistance to bending and impact, making it less prone to deformation after installation;
Selectable colors: The oxide film color can be adjusted through the process (e.g., silver, bronze), balancing functionality and aesthetics, making it suitable for scenarios where appearance is important.
Coated aluminum sheets are made by spraying a layer of polymer coating (commonly PVDF fluorocarbon coating or PE polyester coating) onto the surface of an aluminum sheet. The reflectivity is approximately 75%-80%, slightly lower than mirror and anodized aluminum sheets, but it has the advantage of lower cost and mature technology. It is suitable for scenarios with moderate reflectivity requirements and a focus on cost-effectiveness (such as ordinary greenhouses and household solar reflector devices). Its core characteristics are:
High cost-effectiveness: Simple production process, price is 30%-50% lower than mirror aluminum sheets, suitable for large-area installation;
Good weather resistance: PVDF coating has certain UV resistance and corrosion resistance, maintaining stable performance for 8-12 years in outdoor use;
High flexibility: Rich coating colors (such as white, light gray) can be selected according to the needs of the scenario, and the coating has strong adhesion and is not easy to peel off.