Investigating the Influence of Light Shelf Geometry Parameters on Daylight Performance and Visual Comfort, a Case Study of Educational Space in Tehran, Iran

Daylight can be considered as one of the most important principles of sustainable architecture. It is unfortunate that this is neglected by designers in Tehran, a city that benefits from a significant amount of daylight and many clear sunny days during the year. Using a daylight controller system increases space natural light quality and decreases building lighting consumption by 60%. It also affects building thermal behavior, because most of them operate as shading. The light shelf is one of the passive systems for controlling daylight, mostly used with shading and installed in the upper half of the windows above eye level. The influence of light shelf parameters, such as its dimensions, shelf rotation angle and orientation on daylight efficiency and visual comfort in educational spaces is investigated in this article. Daylight simulation software and annual analysis based on climate information during space occupation hours were used. The results show that light shelf dimensions, as well as different orientations, especially in southern part, are influential in the distribution of natural light and visual comfort. At the southern orientation, increased light shelf dimensions result in an increase of the area of the work plane with suitable daylight levels by 2%–40% and a significant decrease in disturbing and intolerable glare hours.

[1]  Christoph F. Reinhart,et al.  DIVA 2.0: INTEGRATING DAYLIGHT AND THERMAL SIMULATIONS USING RHINOCEROS 3D, DAYSIM AND ENERGYPLUS , 2011 .

[2]  Amjad Almusaed.  Illuminate by Light Shelves , 2011 .

[3]  Harry Wolfarth,et al.  The effects of color psychodynamic environment modification upon psycho-physiological and behavioral reactions of severely handicapped children. , 1982 .

[4]  S. Selkowitz,et al.  Tips for daylighting , 1997 .

[5]  Jean-Louis Scartezzini,et al.  Daylight in Buildings - A source book on daylighting systems and components , 2000 .

[6]  Stephen Selkowitz,et al.  Tips for Daylighting with Windows , 2013 .

[7]  Mark Stanley Rea,et al.  The IESNA lighting handbook : reference & application , 2000 .

[8]  Jeong Tai Kim,et al.  Comparative advantage of an exterior shading device in thermal performance for residential buildings , 2012 .

[9]  Christoph F. Reinhart,et al.  Current daylighting design practice: a survey , 2008 .

[10]  John Mardaljevic,et al.  Simulation of annual daylighting profiles for internal illuminance , 2000 .

[11]  Mohamed Boubekri.  Daylighting, Architecture and Health: Building Design Strategies , 2008 .

[12]  Aik. Meresi,et al.  Evaluating daylight performance of light shelves combined with external blinds in south-facing classrooms in Athens, Greece , 2016 .

[13]  John Mardaljevic.  Verification of program accuracy for illuminance modelling: assumptions, methodology and an examination of conflicting findings , 2004 .

[14]  Christoph F. Reinhart,et al.  Validation of dynamic RADIANCE-based daylight simulations for a test office with external blinds , 2001 .

[15]  Athanasios Tzempelikos,et al.  Efficient venetian blind control strategies considering daylight utilization and glare protection , 2013 .

[16]  Chiara Aghemo,et al.  The approach to daylighting by scale models and sun and sky simulators: A case study for different shading systems , 2008 .

[17]  Ahmed Sherif,et al.  Balancing the daylighting and energy performance of solar screens in residential desert buildings: Examination of screen axial rotation and opening aspect ratio , 2014 .

[18]  I. G. Capeluto,et al.  Strategic decision-making for intelligent buildings: Comparative impact of passive design strategies and active features in a hot climate , 2008 .

[19]  Ahmed Sherif,et al.  The impact of changing solar screen rotation angle and its opening aspect ratios on Daylight Availability in residential desert buildings , 2012 .

[20]  Luisa Brotas,et al.  Parametric Daylight Envelope , 2013 .

[21]  Murat Tuna,et al.  Assesment of Daylighting Performances of Classrooms: A Case Study in Kırklareli Universıty, Turkey , 2015 .

[22]  Christoph F. Reinhart,et al.  ANIMATED BUILDING PERFORMANCE SIMULATION (ABPS) – LINKING RHINOCEROS/GRASSHOPPER WITH RADIANCE/DAYSIM , 2010 .

[23]  John Mardaljevic,et al.  Dynamic Daylight Performance Metrics for Sustainable Building Design , 2006 .

[24]  Khaled A. Al-Sallal.  Daylighting and visual performance: evaluation of classroom design issues in the UAE , 2010 .

[25]  I. G. Capeluto,et al.  Evaluating visual comfort and performance of three natural lighting systems for deep office buildings in highly luminous climates , 2006 .

[26]  Alfonso Soler,et al.  Indoor daylight climate–influence of light shelf and model reflectance on light shelf performance in Madrid for hours with unit sunshine fraction , 2002 .

[27]  Aminatuzuhariah Megat Abdullah,et al.  Building façade design for daylighting quality in typical government office building , 2012 .

[28]  Kjelll Anderson.  Design Energy Simulation for Architects: Guide to 3D Graphics , 2014 .

[29]  Ahmed Sherif,et al.  External perforated Solar Screens for daylighting in residential desert buildings: Identification of minimum perforation percentages , 2012 .

[30]  Chang Sung Kim,et al.  Integrated daylighting simulation into the architectural design process for museums , 2012 .

[31]  B. Ramesh,et al.  Energy Efficient Building Design and Estimation of Energy Savings From Daylighting in Chennai , 2014 .

[32]  Leyla Sanati,et al.  The effect of window shading design on occupant use of blinds and electric lighting , 2013 .

[33]  Christoph F. Reinhart,et al.  The daylit area – Correlating architectural student assessments with current and emerging daylight availability metrics , 2012 .

[34]  C. Reinhart,et al.  Development and validation of a Radiance model for a translucent panel , 2006 .

[35]  Pilar Oteiza,et al.  Dependence on solar elevation of the performance of a light shelf as a potential daylighting device , 1996 .

[36]  Ahmed A. Freewan.  Maximizing the lightshelf performance by interaction between lightshelf geometries and a curved ceiling , 2010 .

[37]  Jens Christoffersen,et al.  Towards a new daylight glare rating , 2005 .

[38]  Al Waary,et al.  Enhancing Daylight and Improving Energy Usage through the Utilization of Lightshelves in Deep Plan Office Buildings in Dubai , 2012 .

[39]  J. Wienold.  DYNAMIC DAYLIGHT GLARE EVALUATION , 2009 .

[40]  Gregory J. Ward,et al.  The RADIANCE lighting simulation and rendering system , 1994, SIGGRAPH.

[41]  Jieun Kim,et al.  Adaptive façade design for the daylighting performance in an office building: the investigation of an opening design strategy with cellular automata , 2015 .

[42]  Jan Wienold,et al.  The daylighting dashboard – A simulation-based design analysis for daylit spaces , 2011 .

[43]  Jan Wienold,et al.  Evaluation methods and development of a new glare prediction model for daylight environments with the use of CCD cameras , 2006 .