日光温室采光性能的实用型优化研究

本研究根据日光温室空间光强渐减的特点,结合BEER-LAMBERT定律,建立日光温室采光性能的数学模型,通过温室平均采光效率SΗ等评价指标,分析了以保定地区为例的模型运算结果,明确了圆弧面、椭圆面、双曲线面、抛物线面4种采光屋面曲线方程的最佳参数。并结合肩高、采光面下土地使用效率Ψ评价指标分析发现,在6种曲线中,两种复合采光面(圆+地窗型和椭圆+地窗型)的SΗ较优而且肩高较大,具有实用性;同时还发现,在同一内跨、脊高和肩高下,二者的采光性能因光程相近而趋同。另外,圆弧面的ΗS最高,但是肩高最小,实用性最差;椭圆面和抛物线面在方程参数优化后表现极为相近,虽然肩高较高,但是SΗ最低。

Studies on practical optimization of lighting performance in solar greenhouse

This paper highlights the practical optimization of lighting performance in solar greenhouse.A mathematic model of lighting performance was established according to the character of weakening light intensity gradually in greenhouse and Beer-Lambert law.Then by analyzing the mean lighting efficiency η_s calculated by the model in the example of Baoding,optimal parameters of equations were obtained among four kinds of curve including circular arc,ellipse,hyperbola and parabola.It was founded by combing η_s with shoulder height h_e,soil utilization ratio Ψ,etc.that the whole performance on η_s,h_e and functional of both circular-linear-roof and ellipse-linear-roof were much better than the others.It was also founded that lighting performance of the two shows similarity under the same of span,roof ridge height and he because of a similar space s between plastic film and lighting objects.In spite of the best η_s on circular-linear-roof among the six curve roof,but its functional was not satisfactory because of its lower h_e.In addition,lighting performance of both ellipse and parabola was especially similar through optimal parameters of equation,but their η_s were the lowest among the six curve roof even though better h_e.