Spectrally Engineered Greenhouse Cool Cover for Energy and Water Efficiency in Diverse Climates

Efficient spectral management of solar radiation is critical for advancing energy‐ and water‐efficient greenhouse operation in cooling‐dominated regions. This study presents the design and simulation‐based analysis of a spectrally selective multilayer cool cover tailored for full‐spectrum modulation across arid, semiarid, and Mediterranean environments. The developed coating is engineered to reflect near‐infrared (700–2000 nm) radiation, mainly responsible for excess thermal load, while selectively transmitting red‐rich photosynthetically active radiation (PAR) (400–700 nm), essential for photosynthesis. Comprehensive simulations reveal that, during summer grow‐cycle (May through September), the cool cover reduced fan energy demand by 0.9–1.1 kWh m −2 , pad water use by 200–250 kg m −2 , and evapotranspiration by 30–40 kg m −2 , while maintaining yield with only a modest 0.2–0.4 kg m −2 reduction in dry mass. Notably, despite a 40% decline in total PAR transmission, the cool cover significantly enhanced light‐use efficiency (LUE), increasing from baseline values of 4.5–5.0 to over 8.5 g mol −1 in most climates. This improvement in LUE underscores the cover capacity to compensate for reduced light availability by mitigating thermal stress and preserving PAR transmission. These results establish the developed cool cover as a viable passive microclimate regulator, offering significant water and energy savings while enabling robust crop production under extreme environmental conditions.