Document Type : Original Article


1 Department of Architecture, Faculty of Art and Architecture, Kharazmi University, Tehran, Iran.

2 Rassam Institute of Higher Education, Karaj, Iran.


Light shelves not only create shade but also improve the uniformity of daylight. In addition to saving energy, they can improve the lighting quality of a space. This research aims to position light shelves and deep windows to enhance energy efficiency and daylight illuminance in classrooms in Abadan (Iran) with hot and dry climates. Rhino/Grasshopper software and Ladybug/Honeybee plugins were used to model and evaluate visual comfort and EUI. By comparing the types of external, internal, and central shelves and in different situations of window depth, the following results were obtained: By combined use of light shelves and deep windows: In central light shelves, energy consumption decreased by 20%, and glare effects were reduced by 53.37%. As a result, installing a window in the depth of the wall did not have much effect on reducing energy consumption, but to some extent, it controlled the intensity of glare. The deep window has reduced energy consumption (13%), and using light shelves has improved energy performance (14 to 20%). Compared to the base model, the combined light shelves reduced UDI by 20% and glare by 53%, while the inside light shelves reduced UDI by 14% and glare by 30%. Therefore, installing light shelves always reduces glare. But if the intention is to save energy, the central and external light shelves in the position of the deep window are very useful.


Main Subjects

  1. [1] Kontadakis, A.; Tsangrassoulis, A.; Doulos L.; C.Zerefos, S. (2018); A Review of Light Shelf Designs for Daylight Environments: Sustainability, 10(1): 71.


    [2] Rashid, M. and Zimring, C (2008). A Review of the Empirical Literature on the Relationships between Indoor Environment and Stress in Health Care and Office Settings: Problems and Prospects of Sharing Evidence. Environ. Behav. 40, 151–173.


    [3] Galasiu, A.D.; Veitch, J.A (2006). Occupant Preferences and Satisfaction with the Luminous Environment and Control Systems in Daylit Offices: A Literature Review. Energy Build. 38, 728–742.


    [4] Hee, W., Alghoul, M., Bakhtyar, B., Elayeb, O., Shameri, M., Alrubaih, M., and Sopian, K.: (2015), The role of window glazing on daylighting and energy saving in buildings, Renewable and Sustainable Energy Reviews, 42, 323-343.


    [5] Sadeghi, S. A., Karava, P., Konstantzos, I., and Tzempelikos, A. (2016). Occupant interactionswith shading and lighting systems using different control interfaces: A pilot field study, Building and Environment, 97, 177-195.


    [6] Mahdavi, A., Mohammadi, A., Kabir, E., and Lambeva, L.: (2008), Occupants’ operation of lighting and shading systems in office buildings, Journal of Building Performance Simulation, 1(1), 57-65.


    [7] Foster, M. and Oreszczyn, T. (2001). Occupant control of passive systems: the use of Venetianblinds, Building, and Environment, 36(2), 149-155.


    [8] Haldi, F. and Robinson, D.: (2010). Adaptive actions on shading devices in response to localvisual stimuli, Journal of Building Performance Simulation, 3(2), 135-153.


    [9] Zhang, Y. and Barrett, P.: (2012). Factors influencing occupants’ blind-control behaviour in anaturally ventilated office building, Building and Environment, 54, 137-147.


    [10] Veitch, J. A., Hine, D. W., and Gifford, R.: (1993). End Users ‘Knowledge, Beliefs, andPreferences for Lighting, Journal of Interior Design, 19(2), 15-26.


    [11] Veitch, J. A. and Gifford, R.: (1996). Assessing beliefs about lighting effects on health, performance, mood, and social behavior, Environment and Behavior, 28(4), 446-470.


    [12] Loonen, R., Trčka, M., Cóstola, D., and Hensen, J.: (2013). Climate adaptive building shells: State-of-the-art and future challenges, Renewable and Sustainable Energy Reviews, 25,483-493.


    [13] Vera, S., Uribe, D., Bustamante, W., and Molina, G.: (2017). Optimization of a fixed exteriorcomplex fenestration system considering visual comfort and energy performance criteria, Building and Environment. 113: 163-174.


    [14] Kontadakis, A.; Tsangrassoulis, A.; Doulos, L.; Topalis, F. (2017). An active sunlight redirection system for daylight enhancement beyond the perimeter zone, Building and Environment 113: 267-279.


    [15] Lim, Y.W. and Ahmad, M.H. (2015). The effects of direct sunlight on light shelf performance under tropical sky, Indoor and Built Environment 24: 788-802.


    [16] Mangkuto, R.A.; Siregar, M.A.A.; Handina, A. (2018). Determination of appropriate metrics for indicating indoor daylight availability and lighting energy demand using genetic algorithm, Solar Energy 170: 1074-1086.


    [17] Gago, E.J.; Muneer, T.; Knez, M.; Köster, H (2015). Natural Light Controls and Guides in Buildings. Energy Saving for Electrical Lighting, Reduction of Cooling Load. Renew. Sustain. Energy Rev. 41, 1–13.


    [18] Doulos, L.; Tsangrassoulis, A.; Topalis, F.V (2014). Multi-criteria decision analysis to select the optimum position and proper field of view of a photosensor. Energy Convers. Manag. 86, 1069–1077.


    [19] Doulos, L.T.; Tsangrassoulis, A.; Kontaxis, P.A.; Kontadakis, A.; Topalis, F.V (2017). Harvesting daylight with LED or T5 fluorescent lamps? The role of dimming. Energy Build. 140, 336–347.


    [20] Reinhart, C.F.; LoVerso, V.R.M (2010). A rules of thumb–based design sequence for diffuse daylight. Light. Res. Technol. 42: 7–31.


    [21] Konstantoglou, M. and Tsangrassoulis, A (2016). Dynamic operation of daylighting and shading systems: A literature review. Renew. Sustain. Energy Rev., 60, 268–283.


    [22] Bellia, L.; Marino, C.; Minichiello, F.; Pedace, A (2017). An Overview on Solar Shading Systems for Buildings. Energy Procedia, 62, 309–317.


    [23] Aschehoug, O.; Christoffersen, J.; Jakobiak, R.; Johnsen, K.; Lee, E.; Ruck, N.; Selkowitz, S (2000). Daylight in Buildings: A Source Book on Daylighting Systems and Components; Report of IEA SHC Task 21/ECBCS Annex 29; Lawrence Berkeley National Laboratory: Berkeley, CA, USA.


    [24] Mayhoub, M.S (2014). Innovative daylighting systems’ challenges: A critical study. Energy Build. 80, 394–405.


    [25] Aizlewood, M.E (1993). Innovative daylighting systems: An experimental evaluation. Int. J. Light. Res. Technol. 25, 141–152.


    [26] Kischkoweit-Lopin, M (2002). An overview of daylighting systems. Sol. Energy, 73, 77–82.


    [27] Littlefair, P.J (1995). Light shelves: Computer assessment of daylighting performance. Light. Res. Technol. 27, 79–91.


    [28] Soler, A. and Oteiza, P (1996). Dependence on solar elevation of the performance of a light shelf as a potential daylighting device. Renew. Energy, 8, 198–



    [29] Bin Othman, M.A; Ahmad, N.A. Ajis, A.M (2017), IOP Conference Series Earth and Environmental Science 67(1):012025.


    [30] Günaydın, T.İ. (2013), “An investigation on daylighting performance in educational institutions,” Structural Survey, 31(2). 121–138.


    [31] N. Gentile; T. Laike; M-C.Dubois (2016). “Lighting control systems in individual offices rooms at high latitude: Measurements of electricity savings and occupants’ satisfaction”; Solar Energy. 127: 113-123.


    [32] Belal, A.; Christian, M.; Catherine S. (2010). “Daylighting Strategy for Sustainable Schools: Case Study of Prototype Classrooms in Libya,” vol. 3, no. 3, pp. 60–67.


    [33] Lim, Y.W. and Heng, C. (2016). Dynamic internal light shelf for tropical daylighting in high-rise office buildings. Build. Environ. 106, 155–166.


    [34] Meresi, A. (2016). Evaluating daylight performance of light shelves combined with external blinds in south-facing classrooms in Athens, Greece. Energy Build. 116, 190–205.


    [35] Berardi, U. and Anaraki, H.K. (2016). The benefits of light shelves over the daylight illuminance in office buildings in Toronto. Indoor Built. Environ. 27, 244–262.


    [36] Lee, H.; Kim, K.; Seo, J.; Kim, Y. (2017). Effectiveness of a perforated light shelf for energy saving. Energy Build. 144, 144–151.


    [37] Warrier, G.A. and Raphael, B. (2017). Performance evaluation of light shelves. Energy Build. 140, 19–27.


    [38] Lee, H.; Jang, H.-I.; Seo, J. (2018). A preliminary study on the performance of an awning system with a built-in light shelf. Build. Environ. 131, 255–263.


    [39] Kim, K.; Lee, H.; Jang, H.; Park, C.; Choi, C. (2019). Energy-saving performance of light shelves under the application of user-awareness technology and light-dimming control. Sustain. Cities Soc. 44, 582–



    [40] Lee, H. and Seo, J. (2020). Performance Evaluation of External Light Shelves by Applying a Prism Sheet. Energies. 13, 4618.


    [41] Mesloub, A. and Ghosh, A. (2020). Daylighting Performance of Light Shelf Photovoltaics (LSPV) for Office Buildings in Hot Desert-Like Regions. Appl. Sci. 10, 7959.


    [42] Lee, H. (2020). A Basic Study on the Performance Evaluation of a Movable Light Shelf with a Rolling Reflector That Can Change Reflectivity to Improve the Visual Environment. Int. J. Environ. Res. Public Health. 17, 8338.


    [43] Lee, H.; Zhao, X.; Seo, J. (2021). A Study of Optimal Specifications for Light Shelves with Photovoltaic Modules to Improve Indoor Comfort and Save Building Energy. Int. J. Environ. Res. Public Health. 18, 2574.


    [44] Brzezicki, Marcin (2021), An Evaluation of Useful Daylight Illuminance in an Office Room with a Light Shelf and Translucent Ceiling at 51° N. Buildings 11(11):494. .


    [45] Ruggiero, S.; Assimakopoulos, M.N.; De Masi, R.F.; de Rossi, F.; Fotopoulou, A.; Papadaki, D.; Vanoli, G.P.; Ferrante, A. (2021). Multidisciplinary analysis of light shelves application within a student dormitory refurbishment. Sustainability. 13, 8251.


    [46] Boyce, P.R (2014). Human Factors in Lighting, 3rd ed.; CRC Press, Taylor and Francis Group: Boca Raton, FL, USA


    [47] Van Bommel, W.J.M (2006). Non-visual biological effects of lighting and the practical meaning for lighting for work. Appl. Ergon. 35: 461–466.


    [48] Rea, M.S. and Figueiro, M.G. (2018). Light as a circadian stimulus for architectural lighting. Lighting Research and Technology. 50 (4): 497–510.


    [49] Figueiro, M.G.; Kalsher, M.; Steverson, B.C.; Heerwagen, J.; Kampschroer, K.; Rea, M.S. (2018). Circadian-effective light and its impact on alertness in office workers. Light. Res. Technol. 51(2): 1–13.


    [50] Bellia, L.; Pedace, A.; Barbato, G. (2014). Winter and summer analysis of daylight characteristics in offices. Build. Environ. 81: 150–161.


    [51] Carli, M.D., Giuli, D., and Zecchin, R. (2008). Review on visual comfort in office buildings and influence of daylight in productivity. In Proceedings of the 11th International Conference on Indoor Air Quality and Climate, Copenhagen, Denmark, 17–22 August 2008.


    [52] Hopkinson, R.G. (1972). Glare from daylighting in buildings. Appl. Ergon. 3, 206–215.


    [53] Clear, R.D. (2013). Discomfort glare: What do we actually know? Lighting Research and Technology. 45(2): 141–158.


    [54] Kruisselbrink, T.; Dangol, R.; Rosemann A. (2018). Photometric measurements of lighting quality: An overview, Building and Environment. 138: 42–52.


    [55] Shin, J.Y.; Yun, G.Y.; Kim, J.T. (2012). Evaluation of Daylighting Effectiveness and Energy Saving Potentials of Light-Pipe Systems in Buildings, Indoor and Built Environment. 21(1): 129–136.


    [56] Hirning, M.B.; Isoardi, G.L.; Cowling, I. (2014). Discomfort glare in open plan green buildings, Energy and Building. 70: 427–440.


    [57] Altomonte, S.; Kent, M.G.; P.R. (2016). Tregenza and R. Wilson. Visual task difficulty and temporal influences in glare response, Building and Environment. 95: 209–226.


    [58] Rodriguez, R.G.; Garretón, J.A.; Pattini, A.E. (2017). An epidemiological approach to daylight discomfort glare, Building and Environment. 113: 39-48.


    [59] Buhari, A.A. and Alibaba, H.Z. (2019), Analysis of Daylighting Quality in Instiyutional Libraries, Energy Efficient Passive Building, International Journal of Electrical and Electronics Research ISSN 2348-6988 (online) Vol. 7, Issue 4, pp: 6-20.


    [60] Chronis, A.; Liapi, K.A.; Sibetheros, I. (2012). A parametric approach to the bioclimatic design of large scale projects: The case of a student housing complex, Automation in construction. 22: 24-35.


    [61] Attia, S.; Hensen, J.L.; Beltrán, L.; De Herde, A. (2012); Selection criteria for building performance simulation tools: contrasting architects' and engineers' needs, Journal of Building Performance Simulation. 5: 155-169.


    [62] Wang, R.; Lu, S.; Feng, W. (2020). Impact of adjustment strategies on building design process in different climates oriented by multiple performance, Applied Energy. 266: 114822.


    [63] Bin Othman, M.A. Ahmad, N.A. Ajis, A.M (2017). Daylight strategies for architectural studio facilities: the literature review, IOP Conference Series: Earth and Environmental Science, Volume 67, 7th International Conference on Environment and Industrial Innovation 24–26 April 2017, Kuala Lumpur, Malaysia,