The assessment of the daylighting performance of a design solution is a complex task due to the changing nature of daylight.A few quantitative metrics are available to designers to assess such a performance,among them...The assessment of the daylighting performance of a design solution is a complex task due to the changing nature of daylight.A few quantitative metrics are available to designers to assess such a performance,among them are the mean hourly illuminance(MHI),the daylight factor(DF),the daylight autonomy(DA)and the useful daylight illuminance(UDI).Each of these metrics has a purpose,a set of criteria and limitations that affect the outcome of the evaluation.When to use one metric instead of another depends largely on the design goals to be achieved.Using Design Iterate Validate Adapt(DIVA)daylighting simulation program,we set out to examine the performance behavior of these four metrics with the changing dimensions of three shading devices:a horizontal overhang,a horizontal louver system,and a vertical fin system,and compare their performance behavior as the orientation changes of the window to which these devices are attached.The context is a typical classroom of a prototypical elementary school.Our results indicate that not all four metrics behave similarly as we vary the size of each shading device and as orientation changes.The lesson learned is that not all daylighting metrics lead to the same conclusions and that it is important to use the metric that corresponds to the specific goals and objectives of the design and of the daylighting solution.The UDI is the metric that leads to outcomes most different than the other three metrics investigated in this paper.展开更多
This paper investigates the main characteristics of daylight on any window in a street canyon.The sky component and the light reflected from the surroundings are described to determine the vertical daylight factor(VDF...This paper investigates the main characteristics of daylight on any window in a street canyon.The sky component and the light reflected from the surroundings are described to determine the vertical daylight factor(VDF).Several street canyon types are characterized taking into account their different height/width and any level of the window is analysed.A simple calculation method uses trigonometric equations based on the sky and the geometry of the canyon.The results were previ-ously evaluated considering different daylight procedures obtained by other studies.This study reveals that the reflectance within an urban canyon plays an important role in the amount of daylight onto any window with more relevance in a deep canyon and low sky view.The graphical presentation that result from this investiga-tion can rapidly assist building and urban designers in an early stage design where assumptions and the lay out of the main design take place.展开更多
Light levels in the churches of the Cistercian Order are mostly related to the fulfilment of liturgical needs.The compound building of Bernardas’Convent includes a church at the utmost southern corner that dates back...Light levels in the churches of the Cistercian Order are mostly related to the fulfilment of liturgical needs.The compound building of Bernardas’Convent includes a church at the utmost southern corner that dates back to the 17th century.It only has one façade facing due southeast.This paper analyses the relationship between daylight conditions within the building before and after the urbanisation of the surrounding area;taking into account the relationship between the church,its main activities,and solar trajectory.A comparative analysis of the relationship between the actual surrounding context and the initial period after it was built(open field)is given.The highest reflectance of the street canyon has augmented the levels of available daylight.展开更多
文摘The assessment of the daylighting performance of a design solution is a complex task due to the changing nature of daylight.A few quantitative metrics are available to designers to assess such a performance,among them are the mean hourly illuminance(MHI),the daylight factor(DF),the daylight autonomy(DA)and the useful daylight illuminance(UDI).Each of these metrics has a purpose,a set of criteria and limitations that affect the outcome of the evaluation.When to use one metric instead of another depends largely on the design goals to be achieved.Using Design Iterate Validate Adapt(DIVA)daylighting simulation program,we set out to examine the performance behavior of these four metrics with the changing dimensions of three shading devices:a horizontal overhang,a horizontal louver system,and a vertical fin system,and compare their performance behavior as the orientation changes of the window to which these devices are attached.The context is a typical classroom of a prototypical elementary school.Our results indicate that not all four metrics behave similarly as we vary the size of each shading device and as orientation changes.The lesson learned is that not all daylighting metrics lead to the same conclusions and that it is important to use the metric that corresponds to the specific goals and objectives of the design and of the daylighting solution.The UDI is the metric that leads to outcomes most different than the other three metrics investigated in this paper.
基金supported with Portuguese national funds by FCT-Foundation for Science and Technology within the UID/ECI/04082/2013 project.
文摘This paper investigates the main characteristics of daylight on any window in a street canyon.The sky component and the light reflected from the surroundings are described to determine the vertical daylight factor(VDF).Several street canyon types are characterized taking into account their different height/width and any level of the window is analysed.A simple calculation method uses trigonometric equations based on the sky and the geometry of the canyon.The results were previ-ously evaluated considering different daylight procedures obtained by other studies.This study reveals that the reflectance within an urban canyon plays an important role in the amount of daylight onto any window with more relevance in a deep canyon and low sky view.The graphical presentation that result from this investiga-tion can rapidly assist building and urban designers in an early stage design where assumptions and the lay out of the main design take place.
文摘Light levels in the churches of the Cistercian Order are mostly related to the fulfilment of liturgical needs.The compound building of Bernardas’Convent includes a church at the utmost southern corner that dates back to the 17th century.It only has one façade facing due southeast.This paper analyses the relationship between daylight conditions within the building before and after the urbanisation of the surrounding area;taking into account the relationship between the church,its main activities,and solar trajectory.A comparative analysis of the relationship between the actual surrounding context and the initial period after it was built(open field)is given.The highest reflectance of the street canyon has augmented the levels of available daylight.
