Filtering Solar Radiation for Cooling the Greenhouse Environment

The double-walled, hollow-channeled, rigid plastic structures are extensively used worldwide for covering agricultural and residential buildings for cooling and heating purposes. This book provides detailed analysis for the transport phenomena of solar radiation through these covers in two cases (i.e., empty or filled with liquid radiation filters). Methods for investigating the optical constants of liquid radiation filters and translucent covering materials were developed. Energy analysis for a greenhouse covered with these covers was established; different physical models were developed and validated with experimental measurements to describe solar, thermal radiation, conduction, convection and water vapor transfer through the cover, crop canopy and moist soil. Smart covering materials made from plastic films or rigid plastic sheets able to reflect the UV and IR and highly transmit the PAR radiations were evaluated to be used for covering greenhouses in hot and sunny regions.