A Method of Computer Simulation of Direct Solar Radiation within Greenhouses——The third part of serial studies on simulation of light environment of farming under structure

The geometric shapes of the lighting roof of greenhouses have a direct effect on the light environment--dailylight integral and its distribution inside,when a definite type of cladding materials is given. All studies in this paper are mainly aimed at what is called a"solar greenhouse".Firstly,six types of mathematical functions are selected to generate six kinds of curves, which involve a circle, an ellipse,a parabola,a hyperbola,a cycloid,and a logarithm. Except for the parabola, each of the other five mathematical functions gives rises to an additional number of curves with various curvature through a certain mathematical transformation, which constitute a cluster of curves to imaginatively construct serial greenhouses in different geometric shapes.Secondly, in accordance with this method of calculation, for the solar radiation in greenhouses previously described in another paper,a model of computer simulation has been developed.Thirdly,by using this model ,the light environment of greenhouses has been simulated. During the whole procedure of simulation,the instantaneous and cummulative distribution of solar radiation,daily light integral,and inclined back surface have been taken into consideration separately.This study is useful as a method and a tool for optimization of greenhouse structure as well as for productive management.