ABSTRACT:"Light well" as one of the most common means of daylight tolls in building, experiences severe limitations and deserve special attention. The question is which strategy is the best for increasing the daylight penetration to the depth of buildings. One of the main challenges in deep plan is to guide daylight into the building core and this can be performed through daylighting strategies, but the choice of the proper innovative daylighting system (IDS) with several parameters is the problem. This paper aims to find elements for optimal choice and selecting context-compatible tools for light well. The result shows that four macro factors were found at the interaction of building and IDS. Identifying the integration components can play an effective role in decision-making or design a new tolls consistent with the physical conditions of light well and building to overcome the daylight crisis. * Corresponding author. Fatemeh Mehdizadeh SARADJ, mehdizadeh@iust.ac.ir

Nowadays, dense cities has led towards the decrease of daylight penetration into the interior space. Daylight crisis in buildings brings significant challenges to architecture, in three domains of economic, health - wellbeing and environment. "Light well" as one of the most common means of daylight tolls in building, experiences severe limitations and requires special attention. The question is which strategy is the best for increasing the daylight penetration to the depth of buildings. One of the main challenges in deep plan is to guide daylight into the building core and this can be performed through daylighting strategies, but the choice of the proper innovative daylighting system (IDS) with several parameters is the problem. This paper aims to find elements for optimal choice and selecting context-compatible tools for light well. The result shows that four macro factors were found at the interaction of building and IDS. Identifying the integration components can play an effective role in decision-making or design a new tolls consistent with the physical conditions of light well and building to overcome the daylight crisis. The present study aimed to identify, evaluate, and weigh the factors affecting the selection of appropriate and innovative daylighting systems for buildings. To this end, a three-phase study was planned and carried out. In the first phase, the factors affecting the selection of daylighting systems for the building were screened and finalized by using the Delphi method in three steps. In the second phase, interactions between criteria and sub-criteria were evaluated by the DEMATEL technique and then the network of communications and significant relationship between them were determined. The analytic hierarchy process (AHP) was employed in the third phase to evaluate the criteria and determine their importance in the selection of daylighting systems. Finally, the relevant sub-criteria were extracted and prioritized. The results indicated that structural, economic, and technical criteria were more effective than functional criteria in the selection of daylighting systems for buildings.

Effective use of natural daylight in indoor spaces contributes to reduced energy consumption in electrical systems as well as improved occupants' visual comfort. Present experiments conduct image recording of three-floor level laboratory building models designed for solar daylight transmission through four different methods (simple window, light-well, and solar light pipes using two different flooring materials) under two incident light angles. The image-based analysis of the probability density functions associated with indoor illumination quantifies the qualitative visualizations of different daylight transmission techniques. It is found that using proper diffuser material for simple windows (direct method) may sacrifice nearly 2% of the light intensity, while significantly enhancing the distribution. In addition, the use of light pipes has provided the best distribution in the environment, which, in some cases, has improved the uniformity of light up to 15.7% compared to other methods. It is shown that the visual discomfort in direct and light-well methods due to the glare formation and indoor lighting non-uniformity under inclined incident light angles can be prevented by using light transmission tubes. At the same time, the use of light tubes at vertical angles improves intensity by up to 17.5% in addition to enhanced light distribution. Present findings based on statistical analysis clearly highlight the significance of quantifying the indoor ambient light distribution in addition to the overall intensity of light. From a practical point of view, the present study suggests that the proper implementation of light transmission tubes results in enhanced uniformity and visual comfort of indoor lighting due to glare reduction while providing sufficient light intensities comparable to other daylight transmission methods. For improved solar light pipe designs, it is also suggested to consider their efficiency dependence on the tube length as well as flooring materials.