All‐Solid‐State Electrochromic Variable Emittance Coatings for Thermal Management in Space

The results presented in this article demonstrate the feasibility of “all‐solid‐state” inorganic electrochromic (EC) variable emittance coatings (VEC) for thermal management in space. VECs were built on glass substrates, flexible polyimide (Kapton™) films, and on high resistance silicon wafers. The best VECs were found to modulate mid‐infrared emittance from 0.15 to 0.46 on a Kapton film and from 0.24 to 0.48 on a silicon wafer that performs the dual role as both infrared window and substrate. The results of thermal estimations for a two‐dimensional plate showed that EC systems with emittance modulation ratio ehigh/elow = 3 can be practically used to advantage in providing enhanced thermal control for lightweight structures in space. In addition, EC variable solar reflectance coatings (VSRCs) were built on polyethylene terephthalate (PET) film. The average reflection of the VSRC in a visual spectral range was 63% in the bleached condition and 20% in the colored condition. Thermal analysis shows that a com...