Improvement of greenhouse insulation with restricted transmission loss through zigzag covering material

The design of modern greenhouses is based on a compromise between a maximized transmission of solar radiation and a minimized heat loss within an economic context. This could be satisfied by the use of transparent double-layered zigzag plates as a covering material. The MatLight computer model was developed to compute the effect on transmission of a greenhouse cover due to the use of these plates. A greenhouse cover without construction elements such as gutters and glazing bars, with a span width of 3.2 m and a roof slope of 25 degrees, was covered with a double zigzag plate. This greenhouse was proved to have a diffuse transmission loss of 1.6% and a gain in transmitted direct radiation up to 5% in winter for NS-orientation, compared with a single-glass cover. The insulation of the cover increases by 16%. This is a promising result for practical application. (C) 2001 Silsoe Research Institute.