Eliminating greenhouse heat stress with transparent radiative cooling film
Hao Zou, Chenxi Wang, Jiaqi Yu, Danfeng Huang, Ronggui Yang, R.Z. Wang
Abstract
Greenhouse cultivation is becoming increasingly important to feed the growing population. Temperature needs to be regulated properly for greenhouse production. Herein, a 115-μm-thick transparent radiative cooling (T-RC) film is specially designed as a covering material for greenhouses to reduce heat stress without sacrificing photosynthesis. With high emissivity in atmospheric window, high transmittance in photosynthetically active radiation (PAR), and high reflectivity in near-infrared radiation (NIR), T-RC film is demonstrated to lower the indoor temperature of a greenhouse by 18.6°C without ventilation compared with polyolefin (PO) film. The productivity of three varieties (Chinese cabbage, pakchoi, and cherry radish) was accelerated by 23.4%, 17.3%, and 21.7%, respectively, within 19 days after seeding. Moreover, a modeling study shows that this film can save cooling water by 64.8%. This study paves the way for highly productive greenhouses in hot regions with high productivity and high crop quality, along with both energy savings and water savings.