Currently, greenhouses are widely used for the cultivation of various crops. However, in tropical and subtropical regions, undesired near-infrared radiation (NIR) causes heat loads inside the greenhouse. Recent works have demonstrated that radiative cooling, releasing energy via radiative heat exchange where the heat is dumped directly into outer space, can be achieved by using silica particles designed to emit in the infrared atmospheric transparency window. The purpose of this study is to improve the plastic greenhouse cladding to regulate the temperature inside the greenhouse, mainly by passive cooling. Low-density-polyethylene (LDPE)-based formulations with anti-fogging agent, UV stabilizer, and silica particles were prepared by the melt blending technique and were formed into a double film by extrusion molding. Experimental results showed that under 35 °C ambient conditions, the inner temperature of the simulated greenhouse with the newly developed cladding was 4 to 5 °C less than that of the greenhouse with the commercial agricultural polyethylene (PE) film.
Keywords: covering material; near infrared radiation; passive cooling.