Optimization of Daylight Performance Based on Controllable Light-shelf Parameters using Genetic Algorithms in the Tropical Climate of Malaysia

Abstract

This study aims to achieve a balance of daylight availability in the work-plane environments of a fully glazed facade integrated with a light shelf system using an optimization procedure that can assist architects with assessing the daylighting performance of numerous design alternatives, and build-up the optimized design. The approach uses parametric design, simulation modelling, and genetic algorithms. A case study of a typical office is carried out to test and verify the effectiveness of the optimization procedure for a light shelf system. Five parameters of light shelf design are optimized in two solar solstices (June and December) and one equinox in March under the Malaysian sky conditions. The optimization results indicate that the optimal design options of light-shelf parameters have great potential for illuminance improvement. After the optimization, the daylighting performance of useful daylight illuminance compared to reference models is increased respectively with an average value of 15.6% and 4.7% on the 21st of June, and by 17.5% and 5.8% on 21st of March, and by 5.8% and 11.3% on 21st of December. Statistical analysis is achieved to investigate the relationship between the performance metric of the optimal design options and the other cases, the outcomes showed that the regression analysis indicated a high level of reliability as well as different levels of variation coefficients.

Impact of Internal Shading Controls on Efficient Daylighting in Home-Office Workspaces in Tropical Climates

“…These particular dates were selected to represent the most serious climatic conditions of the sun path in the tropical sky of Malaysia. In other words, the highest and the lowest solar altitudes are recorded on the summer and winter solstices, respectively, while the sun's altitude lies between the values of these two solstices on the equinox [50]. To experience different behavior of the sun concerning the room's window, all cardinal orientations (North, South, East, and West), and three critical times during a day (9:00 a.m., 12:00 p.m., and 3:00 p.m.), representing different solar azimuth angles, were employed for the simulation tests.…”

“…Referring to previous studies, clear and tinted window films are commonly used in residential buildings in tropical regions [20,47,48]. Window glazing with the visible transmittance (vt) of 20% to 80% is mostly used In Malaysia [49,50]. In another study by Lim et al, [51], the visible transmittance of 53% and 54% were used in several existing buildings in Malaysia.…”

“…Accordingly, eWPI is dependent on DR and also estimated outdoor illuminance which was obtained from the real measured data for the Malaysian tropical skies [57,58,62], and the weather data file (EPW) for Johor Bahru, Malaysia, taken from the online website [63]. eWPI = (DR / 100) × Estimated Outdoor Dynamic daylight metrics such as UDI have been widely used to evaluate daylight efficiency in buildings for different climatic conditions [50,[64][65][66][67]. UDI is specified as the yearly occurrence of daylight illuminances in a certain range called "useful" by the users; when daylight illuminance values are in the range of 100-500 lx, it is considered as "UDIsupplementary" [50,67].…”

“…eWPI = (DR / 100) × Estimated Outdoor Dynamic daylight metrics such as UDI have been widely used to evaluate daylight efficiency in buildings for different climatic conditions [50,[64][65][66][67]. UDI is specified as the yearly occurrence of daylight illuminances in a certain range called "useful" by the users; when daylight illuminance values are in the range of 100-500 lx, it is considered as "UDIsupplementary" [50,67]. Moreover, Dubois [68] claimed that WPI of 100-500 lx is acceptable and ideal for desk-related tasks, while WPI of lower than 100 lx and higher than 500 lx is inappropriate for such tasks.…”

Comparative Study on Computer Simulation of Solar Shading Performance with Heliodon and Artificial Sky

“…An office space with single glazed, window-wall façade bounded by walls on the sides is adopted for the procedure to depict the typical spatial configuration of multi-story open-plan office buildings in Malaysia [19,32,33]. The room measures 9 m by 6 m, with floor-to-ceiling height of 3m, with no consideration for furniture layout or occupancy density.…”