As a clean sustainable source of lighting, daylight is currently the subject of rigorous studies. It has been demonstrated that daylight is not only a source of lighting, but also important in physiological and biopsychology of human beings. Although current knowledge on this subject is at its prime, there are still some design recommendations to achieve adequate daylight in buildings.

Natural light has been an important element in Iranian architecture and shaped interior spaces of monuments.During different historical periods, the presence of light in various Architectural works, have always been under focus from spiritual religious aspects in addition to the functional aspect. The incentive towards light direction during worship has existed in different religions and still exists. daylight has always had a special place and value in Islam and the Islamic worldview. With emerge of Islam, usage and application of light in architecture increased especially in mosques as the most important monuments of Islamic architecture.daylight, in addition to functional aspect, is considered as a mystical symbol and a sign of God's presence in the mosques, which raises the human sense of reverence and humility in front of God. To this end, for centuries, Iranian architects have been trying to use traditional architectural elements and day lighting solutions to improve the deployment of natural light in their designs.This study attempts to investigate and evaluate the application of light-catching elements in Iranian mosques, particularly in mosques and mosque-schools from Qajar period. We use a descriptive and analytical research method and our study is mainly on the basis of resources and the literature available in Iranian libraries. After describing the theoretical foundations of our research, we analyse a number of common light-catching elements through research’s selected mosques. Although a multitude number of studies have been done on the concepts of light and its role and function in the traditional architectural monuments, particularly mosques and homes, little study has been done on light-catching elements in mosques of a specific period as done in this research.Structural elements which have been used in Iranian traditional architecture for utilization of daylight are studied from two directions. In the first direction, light-catching elements often have the task of transmitting light into the interior space. In the second direction, light controlling elements adjust the entered light through the building (similar to canopies). The subject of this research is in line with the first direction. We only study light-catching elements and we chose thei common elements such as door and window, Shabak, Horno, Rozan and Roshandan. Although these elements are different in term of material, type and location of application in the building, all of them are used for light-catching even though some of them are also containing ventilation application. We chose 10 mosques and mosque-schools of Qajar period in Tehran. The examined mosques and mosque-schools in this research were selected based on the following criteria: first, all the selected mosques and mosque-schools are located in old and valuable regionof the city and they are tourist attraction. They have architectural values and are well-known among people and experts. Secondly, the buildings of selected samples reflect prominent features of Qajar’s architecture.Also the sufficient information (including maps and images) are available for these monuments. We chose 5 mosques and 5 mosque-schools among Qajar’s architectural works. Then, the usage and the application rate of light-catching elements in these buildings are evaluated quantitatively and qualitatively by the use of maps and the available visual data. Quantitative analysis is based on the approximate numbers of elements used in these mosques which have been extracted from the available images and maps. To qualitatively evaluate the application rate of various methods of light-catching in these mosques, we specify four levels of usage: "insignificant", "low", "medium" and "high". We provide the results of quantitative as well as qualitative analysis in this paper.Our analytical studies indicate that although door and window, Shabak, Horno, Rozan and Roshandan had been considered as innovative lighting elements inside mosques of Qajar period, architectures of this period still mainly used door and windows as the main lighting elements. Next to doors and windows, Rozan stands at the second place, Horno in the third place, and then Shabak and Roshandan. The utilization rate of doors and windows among considered mosques and mosque-chools has been similar. Nevertheless, the usage of Horno as a lighting element in mosques has been more than mosque-chools. Rozan and Shabak have yet been used more in mosque-chools rather than mosques. Roshandan has been barely used in the mosque schools, and only few samples could be found within some mosques of this period.

Background and aims: Apart from visual effects of daylight it has observed to elicit powerful non visual effects. It controls the circadian rhythm of hormone secretions and body temperature with implications for sleep/wake states, alertness, mood and behavior. In this study new metrics called "daylight Autonomy" and "Useful Day light Illuminance" were calculated utilizing south facing vertical illuminance values for industrial parks of Tehran province.Methods: Measurement of south facing vertical values was carried out between 12 July and 1 August 2007 in three measuring stations (Hamadan, Eshtehard and Kerman). Synchronically calculation of corresponding values was performed using method of Illuminating Engineering Society of North America (IESNA, 2000). Once aproper model was fitted between measured and Calculated values, prediction of south facing verticali lluminances was under taken for 11 industrial parks of Tehran in a working year. Consequently metrics of "daylight Authonomy" and "Useful daylight Illuminances" were estimated for an assumed work place in industrial parks.Results: Minimum, maximum, mean and standard deviation of predicted values for total data found to be 5, 88.32, 50.14 and 23.35 Klux respectively. Values of "daylight Authonomy" and "Useful daylight illuminances" were found to be 56% and 56%-100% respectively.Conclusion: There is high potentiality for daylightv availability and energy conservation in Industrial parks. The maximum external illuminance was found 88KLux for all industrial parks. This value could produce internalilluminaceexceede630 Kluxwhich could not make glare and discomfort for occupants.

To achieve sustainable, low-energy buildings, it is required to further emphasize on accurate evaluation of daylight performance. To this end, over the last few years, researchers have considerably developed more advanced dynamic metrics to overcome the limitations of static metrics. Nowadays, daylight Autonomy (DA) and Useful daylight Illuminance (UDI) metrics and those metrics developed based on these two are the most well-known dynamic daylight performance metrics, which do not have the same credit in terms of efficiency among different experts. The present study aims to compare the abilities of these metrics to be used in evaluating daylight performance in educational buildings. To this end, a parametric analysis is performed through simulation in Grasshopper software using Ladybug and Honeybee plugins. This analysis is performed to show the relationship between UDI, sUDI, DA, sDA, cDA metrics by examining the effects of the variations of Window-to-Wall Ratio (WWR) on them in a typical Classroom of an elementary school in Tehran. The results show that the lack of a high limit for DA and DA-based metrics, i. e. sDA and cDA, eliminates their correlations with the components related to the occupant comfort. Among various daylight metrics, UDI, due to its correlation with glare and energy consumption, can indicate the propensity for the occurrence of occupant discomfort as well as the energy consumption. Also, among UDI-based metrics, sUDI needs to increase the density of sensor points in the grid to achieve the same accuracy as UDIavg, significantly increasing the computation time. Therefore, the UDIavg metric is more suitable to use for small spatial units where the number of sensors is quite limited.

The perceptual performance of daylight is focused on the assessment of daylight at the eye level and its relation to the psychological (perception, emotional state) needs of the occupants, which influenced by architectural elements that shape the way daylight enters the space, such as multilayered faç ade and perforated walls. However, it seems that the designers do not have a clear and systematic understanding of the physiological and psychological effects of these patterns in interior spaces. through a structured review of previous research, this paper seeks to identify, quantify and predict the relationship between daylight distribution patterns linked to architectural elements that shape the way daylight enters the space (independent variable) and occupants perceptions (dependent variable) in daylit spaces. The findings showed that Human experience can be represented with two dimensions, valence and arousal. To explore these two dimentions, subjective evaluations based on self reports using questionnaires, objective evaluations based on physiological data and observations based on physically based rendering (PBR) in virtual reality (VR) environment have been carried out. the results show that the best image-based computational measures of contrast in predicting perceptual effects of daylight are modified spatial contrast indicator (mSC) and the size of images compressed in JPEG format and PNG-PERIM8 edge detection indicator (for evaluating the complexity of images). for the evaluation of perceptual effects of other visual stimuli, two-dimensional Fourier amplitude spectrum metric (FFT2) is used. In conclusion, the findings of this research can be the basis of a wide range of experimental research on this topic in the future.

Light has various forms and degrees which causes latent concepts. Light makes everything seem clear. It is also expressed as a transcendental concept in religion. Beyond this, light has a considerable role to play in designing architectural spaces and without it, neither space nor form and colour, are visible. In architectural spaces, natural light creates various qualities which leads to different meanings and concepts. It is a significant point that light has multi-dimensional aspects which influences human beings’ perception. In other words light is not just a physical necessity but it has psychological and semantic value as an important and noticeable factor, and has affected human life. Therefore in Iranian architecture functional and conceptual approach to the subject of light, leads to creation of spiritual space in addition to functional ones. The multi-dimensional nature of light, reveals the necessity of taking attention to its physical and semantic aspects in different disciplines. This research aims to clarify, how the semantic quality of space by receiving daylight, is perceived. The research background shows that the semantic aspects of quality and its relevant parameters, have not been investigated adequately in preceding studies. Considering this, on the one hand, and the importance of day light as a natural resource which improves semantic quality of space; on the other hand, provided adequate reason to propose a research which attempts to investigate how the daylight affects the semantic quality of space. The main assumption of this research is that reaching the spiritual light, can be achieved by use of physical light in a targeted way. Therefore, in this paper, a qualitative research methodology with an analytical-interpretational and logical reasoning approach was used to provide an appropriate framework for process of understanding the semantic quality of space using daylight. In order to achieve the considered goals, first, the light was studied in the Holy Qur'an to investigate its function and application in general from the Islamic point of view. Types and degrees of light were extracted and classified at this stage. Second, the levels of meanings, was studied. This study tried to identify the levels of human perception. Determining the levels of space meaning perception and finding its relation with light degrees, clarified the main fact of the study. It manifested that, each one of the light degrees is percept by one of meaning levels. In this process, one of Imam Ali’ s valuable expression, relating to this field, was used as an analytical and comparative tool. Consequently and based on previous findings shown in diagrams in the research process, a model of meaning perception, was proposed. This model reveals the quality of reaching spiritual light by the use of physical light. This approach to the subject introduces the light’ s role in response to the metaphysical needs of human as opposed to its functional ones. The proposed model can reduce the gap between a high-level conceptual approach to the light and its physical application in architectural spaces and, ultimately can indicate the quality of the space meaning perception.

daylight Glare Probability (DGP), founded on the latest glare metric, is the main challenge related to daylight glare inside buildings. Studies showed that the DGP depends on several factors, such as vertical illuminance values at the human eye factor, which is an essential parameter. In this study, we implement machine learning techniques to estimate and predict the DGP classifications, which are imperceptible, perceptible, disturbing, and intolerable based on the various influenced factors. A series of machine learning simulations have been conducted to investigate how those factors can be influenced by the degree of glare and classifications. In this research, different machine learning algorithms such as Artificial Neural Networks (multi-layer perceptron), K-Nearest Neighbors (KNN), Support Vector Machines (SVM), and Random Forest (RF) were employed to determine or predict the DGP classifications accurately. Results showed that the RF is the most effective method to classify the DGP and can predict with up to 99 % accuracy. Furthermore, the results displayed that vertical illuminance at eye level (lux), Ev, compared with other factors, has the largest influence on the DGP classifications. Consequently, machine learning is a powerful, promising, and viable option to implement in building constructions to optimize energy consumption, a global issue in the current century.

Various researches have introduced methods to use daylight in office buildings in the Middle Eas t zone, but none of them have ever considered the use of plant leaf arrangement, called phyllotaxis, as a comprehensive solution for harves ting daylight. The idea of the Phyllotaxis Tower has been raised for several years but the main ques tion of this research is whether using the phyllotaxis model is capable of exploiting daylight in high-rise buildings or not. So, in response to this ques tion, the main aim of the research was set to evaluate daylight efficiency in high-rise office buildings by presenting an exemplary and phyllotaxis-inspired design. The research method is encompassed several s teps including, s tudying the literature on the subject firs tly, then modeling a prototype building based on the Biomimicry Problem-Based approach, and eventually computer simulation to evaluate the performance of the proposed building. The results show that office units can get daylight illuminance of 500 lux at 50% of operating time per year in addition to proper performance on four single days of different seasons of the year. Furthermore, the sample building obtained label B of energy consumption from S tandard No. 14254 presented by the Ins titute of S tandards and Indus trial Research of Iran, which has been compared with the energy label of 45 office buildings in the same location and same climate conditions, based on the figures are defined on the aforementioned s tandard and has the bes t performance among them.