ENGINEERING RESEARCH JOURNAL (ERJ) Vol. 1, No. 50 October 2021, pp. 140 - 134 Journal Homepage: erj.bu.edu.eg - 135 - Daylighting Retrofitting in Existing Educational Spaces (By using Solar Tube( “A Case Study of Design Studio Hall in Cairo, Egypt” Omnia Abdel-Halim Mohamed Ibrahim , Prof. Ahmed Atef Eldessoqy Faggal, Assoc. Prof. Ashraf Ali Ibrahim Nessim Department of Architecture Faculty of Engineering, Ain Shams University Abstract :Recently, many researchers have been interested in designing the buildings to get the benefit from daylight inside, which saves a lot of building consumption for artificial lighting, which gives visual and thermal comfort and also contributes to reducing costs. But a few of them were interested in how to modify the designs of the existing educational spaces that did not reach daylight, which increases the consumption of these spaces for industrial lighting and gives a lack of a sense of visual and thermal comfort, and that is inconsistent with the principles of designing educational spaces that aim to reach the maximum visual comfort for the student, which helps in raising the performance of the student during the educational process. Therefore, this research will cover possible retrofits of daylight with existing educational spaces using modern daylight techniques to reach the visual comfort which students need. Keywords: Innovative day lighting systems, Retrofitting, Educational Spaces, Solar Tube, Spatial day lighting Autonomy (sDA). 1. Introduction But now with the development of global warming, it is important to try to replace the electrical energy consumed in artificial lighting with daylight, which reduces lighting consumption (and cooling), but also effectively reduces peak electrical loads. And through the current development in technology, many of the systems have been developed, as the efficiency of the system has increased significantly. Furthermore, during the summer months, it can be difficult to reduce solar gains and achieve adequate daylight levels, leading to a trend to improve facade designs to meet both needs. This is done by many methods, such as improving shading systems (such as blinds, rollers, etc.), which reduces the supply of daylight. During the past periods, bringing usable daylight deep into the core of the building or in areas that are not lit by day has become one of the most important challenges, which could lead to significant savings in energy consumption while creating an attractive visual environment. Conventional window systems can provide sufficient daylight in areas near building openings (the perimeter). The increase in this area can be achieved either by using a design strategy with respect to a different building form (i.e with an