Investigation of dual ducting system for daylighting office buildings in Dhaka

Abstract

With rapid development, commercial and economic activities increase parallel which accommodate lots of office spaces and buildings in Dhaka city. Deep plans are a common practice in middle and high-rise office building design, and large open plans have become the preferred office layout by modern businesses due to the flexibility of the space and economic benefits achieved from maximum plot to gross floor area ratios. Environmentally conscious assessments of building design are recognizing that daylight (along with natural fresh air) is an important commodity and should be exploited to the full. Generally, people when asked, always prefer to work in a daylit environment. There is a growing acknowledgement that daylight produces positive effects, both physiological and psychological. Consequently, the deep core areas of these buildings is difficult to be naturally illuminated by side windows, and depend entirely on electricity for illumination. Often major spaces of office buildings are running with artificial lighting. Recent studies suggest the artificial lighting accounts for close to 50% of the total energy use in a building, through daylight is readily able to replace much of this energy use. Daylight is a major influence on building design. The light pipes are innovative devices able to transport and distribute daylight without heat transfer in dark rooms. Innovative daylighting strategies seek to break the conventional strategies barriers and ‘guide’ daylight beyond their limits to the remote zones and windowless spaces, whether in new or existing buildings. Daylight Guidance System (DGS) use lightpipes to distribute daylight, which occupy significant amounts of space. Most of the office building is also running with artificial heating, cooling and ventilation system which already occupy a lot of ceiling space of the buildings. The integration of light ducts with heating, ventilation and air conditioning (HVAC) ducts (dual ducting system) could be a practical solution that may ensure quality working environment, energy saving, reduction of costs and space management. The aim of the research is to study the installation of light pipe with HVAC ducting system and explore an integrated system (dual ducting system) for office buildings to increase the use of daylight in working space in the context of Dhaka. To explore the possibilities of installing lightpipe, computer simulation analysis were used by EnergyPlus software. Further simulation analysis was done to refine the design parameter, e.g. length and width, number and position of light pipe for the most effective use of daylight. Results indicate that, there is a considerable potential for daylight inclusion into the deep office space by installing light pipe. Literature review, field observations, model experiments and simulation studies together provide the basis of design guidelines for consultants to design appropriate luminous environment. It is expected that the design strategies and recommendations from this research will improve the luminous environment of deep spaces of office buildings of Dhaka by installing duel ducting system.

Keywords Dual Ducting System, Light Pipe, HVAC, Daylighting, Office Building.