Study on interior lighting design using Monte Carlo simulation

近年来，根据各种照明系统的选择，室内照明设计有增加复杂性的趋势。传统的基于积分方程法的照度分布预测方法被广泛用于预测照度分布，但在许多实际的室内环境中，假设有凸面封闭、完全漫反射和光强分布均匀等条件，并不一定都能满足这些要求，相反，蒙特卡罗模拟(MCS)由于其对复杂照明系统的广泛适用性而具有很大的优势。本文研究了MCS在解决各种照明设计中的互反射问题，主要研究成果如下：(1)空、非空室内光通量的分布与守恒。用MCS和常规理论方法计算了空、非空立方体内墙表面的照度分布。从这些结果可以看出，无互反射的照度分布的模拟结果与理论结果基本一致，并且很好地保持了墙面互反射时的光通量守恒定律。(2)不同反射率的室内不同光强分布的照度分布计算。许多灯具通常具有不对称的发光强度分布，此外，反射率或墙面由朗伯特性和镜面反射特性组成。为了考虑这些特性，假设这些现象可以用逐步函数作为离散的概率事件来创建，成功地实现了无限长内部墙面上的照度分布。离散概率事件的计算结果与连续概率事件的计算结果吻合较好。

Recently, interior lighting designs trend to increase their complexity according to the choices of various lighting systems. Conventional methods based on the integral equation have been widely used to predict the illuminance distribution, where assuming convex enclosures, perfectly diffuse reflection and symmetrical luminous intensity distribution, etc. however, in many practical interiors all of them can not necessarily be satisfied.On the contrary, the Monte Carlo simulation(MCS) has a large advantage due to the wide applicability without any limitation to the complicated lighting systems. This study deals with the application of MCS to solving the interreflected problem in various lighting designs.Main research results obtained using MCS are summarized as follows;(1) Illuminance distribution and conservation of luminous flux in empty and unempty interiors. Illuminance distributions on wall surfaces in both empty and unempty cubic interiors are calculated by MCS and conventional theoretical methods. From these results it can be concluded that simulation results of illuminance distribution without interreflection almost agree with theoretical ones, and the conservation law of luminous flux with interreflection between wall surfaces is well kept.(2) Calculation of illuminance distribution with various intensity distributions in interior having different reflectances. Many luminaries have usually asymmetrical luminous intensity distribution, furthermore, reflectances or wall surfaces are composed of Lambert's and specular properties. In order to take account of these properties, assuming that these phenomena could be Created as discrete probability events using stepwise function, illuminance distributions on wall surfaces in infinitely long interior are successfully carried out. The calculated results obtained from the discrete probability event well coincide with that for the continuous ones.