Analysis for optimization of energy efficiency in office buildings in Sri Lanka

Energy consumed in the building sector consists of residential and commercial end users and it accounts for 20.1% of the total delivered energy consumed worldwide [22].Global primary energy demand is projected to increase by annual rate of 1.6% between 2004 and 2030[23]. There are building codes, Standards, Guidelines etc. to regulate and promote energy efficiency in building sector [page 33]. Sri Lanka also had focused on minimising these increasing trends during the past decade. “Code of Practice for Energy Efficient Buildings in Sri Lanka 2008” was introduced as an initiative. Sri Lankan government is carrying out various programmes, seminars and activities to encourage building owners, developers, designers to implement energy saving measures. In this research three commercial buildings in Colombo region having 8, 8 & 10 floors and total floor areas of around 35 000 ft2, 60 000 ft2 & 90 000 ft2 and monthly average energy consumption around 50 000 kWh, 70 000 kWh & 100 000 kWh were selected. The study and analysis were done to find out whether there are none-compliances of the selected buildings with ASHERAE 92.1-2007 standard and Code of Practice for Energy Efficient Buildings in Sri Lanka-2008 which are used by professionals in the subject and to find out whether there are opportunities to improve energy efficiency of already constructed buildings further by modelling those buildings in Trace 700 software by simulating various possible options. None of the three selected buildings fully complied with the standards considered. Major weak points were poor building envelope sealing, insufficiency of usage of automatic controls, improper balancing of systems, poor lighting system efficiency , higher lighting power density and higher Solar Heat Gain Coefficient of vertical glazing. Though Building Automation Systems (BAS) are installed, it was revealed that by adding/upgrading some new features/options to BAS and by eliminating the weaknesses found, there are still more opportunities to increase energy efficiency further significantly