Teaching design of photothermal focusing experiment induced by concave glass curtain wall based on caustic effect
[Objective]The presence of glass curtain wall buildings with concave facades may strongly reflect and concentrate sunlight,causing intense glare and high local temperatures.These conditions can result in traffic accidents,skin burns,vehicle damage,fires,and other serious accidents.This issue arises owing to architects'insufficient application of physical environmental knowledge when designing these buildings.To help future architects fully understand the implications of photothermal focusing induced by concave glass curtain walls,an experimental project of concave glass curtains based on the caustic effect was developed.[Methods]The project included five steps.(1)Students are first introduced to common caustic phenomena in daily life.The causes and theoretical basis of photothermal focusing are explained.(2)A scaled model(1:300)of an actual concave glass curtain wall building with a concave facade in China is created.This involves customizing a curved transparent glass and setting an opaque plate with the same curvature behind it to form a little glass curtain wall room.An 800 mm × 800 mm black plate serves as a diffusely reflective surface to capture the reflected sunrays.Once the glass curtain wall model is positioned on the black plate,a scaled experimental model is complete.(3)Using a thermal imager,students take a light intensity distribution map to observe the light intensity and temperature distribution on the black plate.(4)Such a photothermal focusing experiment should be carried out on flat and unobstructed ground on a sunny day.In the experimental process,the experimental model's concave facade should be oriented toward the sun by slowly rotating it from east to west.This allows students to observe the caustic line's appearance to disappearance over time on the black plate.Then,students use thermal imagers to quickly record the spatial and temporal distribution of light and heat.(5)Finally,based on theoretical analysis and experimental results,students develop coping strategies to avoid or solve photothermal focusing issues in glass curtain wall building designs.[Results & Conclusions]During preliminary experimental teaching,students observed caustic lines of light that met the characteristics of the caustic effect.However,the cusp location sometimes shifted east or west.Thermal images compared that temperatures in the focal area were significantly higher than those in other areas,especially at the cusp position.The experiment engaged students deeply,making them aware of the importance of integrating physical environment knowledge into building design.The distinctive nature of the experiment,integrating light with heat,building form with physical technology,theory with practice,and photothermal imaging with quantitative data,effectively achieved its educational purpose.
building formphysical environmentphotothermal imagespatial and temporal distributioncoping strategy
万方数据
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