Daylight modelling and thermal performance of atrium of new MECM building at Putrajaya

Abstract

Putrajaya, Malaysia. The LEO building was designed to incorporate renewable and energy efficiency strategies. Several window designs were considered for the new showcase building. To ascertain that innovative window designs achieve the low energy consumption objectives, a study was done to analyse and compare the effect of several adaptations of the punch-hole window designs on the illumination levels of the indoor spaces of the office building. Architectural scale models were used under a sky simulator to analyse the impact of those window designs on indoor illumination. A scale model of the atrium section of the building was also studied to assess the daylighting performance of the atrium. Again, a sky simulator designed and built to conform to the tropical sky model, was used for the purpose. However, naturally-ventilated atriums are not commonly found in hot-humid climates. Therefore, this paper presents the results of the daylight modelling and the thermal performance of an atrium designed to consume low energy. The daylighting performance was determined for each floor of the 5-storey structure using the daylight factor method. The calculation of the absolute indoor illuminances was done using solar and daylight modelling. The thermal performance was evaluated using Computational Fluid Dynamics (CFD) simulations using Climate Model Year Data and architectural parameters as input. The thermal performance was analysed based on temperature differences and airflow characteristics. It was found that the atrium provides indoor lighting for the office spaces within the recommended levels. The temperature differences, airflow distribution and velocities also indicate that indoor thermal comfort is not compromised despite of the energy minimizing considerations. The results of this work have actually been incorporated in the design of a low energy MECM government office of which the construction is in the last stages of completion in Putrajaya, Malaysia. This paper also presents the recommendations made on the possible improvements to the basic design in order to optimize natural daylighting and natural ventilation while protecting the building façade from solar thermal penetration.