Radiative Control Through Greenhouse Covering Materials Using Pigmented Coatings

摘要

Greenhouses are built in hot climates to provide a cool environment suitable for growing out of season crops. Usually their temperature is controlled by utilizing air conditioning systems, or shading the transparent cover material in peak sun hours. A new method to keep a cool greenhouse, and reduce energy consumption is proposed in this study. Using a new approach for pigmented coatings that would reflect incident solar radiation in the infrared wavelengths and allows the shorter visible wavelengths to be transmitted, it is possible to reduce the heat gain inside the green house by radiation. A series of numerical calculations was done, solving the radiation transfer equation using the Radiation Element Method by Ray Emission Model (REM~2). Mono dispersed particles where assumed and Mie theory was used to estimate the radiative scattering properties of the particles. Different materials were studied as pigments, and compared over a range of particle sizes and volume fractions. Diamond was found to be the most appropriate candidate for the desired application.