TROPICAL AND SUBTROPICAL GREENHOUSES - A CHALLENGE FOR NEW PLASTIC FILMS

Abstract

In subtropical and tropical regions it is necessary to get a cooling effect if high irradiation heats up the greenhouse.It is possible to use covering materials, which contain absorbing, reflecting, interference, photo-or thermochromic pigments.Reflecting and coloured films containing absorbing pigments intercept PAR and give a shading effect throughout the year.More intelligent materials with interference pigments are able to reflect parts of the NIR more selectively.Photoand thermochromic materials are in principle able to keep out NIR only during periods with high irradiation.For the subtropics there is a need for thermic films, which prevent the transmission of FIR during cold nights and so create an insulating effect.