Methods to move to zero energy commercial building (ZECB) for the future

Abstract

This study aims to develop methods to reduce energy demand in the building sector, which is one of the main energy consumers. An extensive literature review has been carried out to understand the behaviour of buildings’ energy consumption and investigate the previous methods proposed in tackling building’s energy consumption. This work mainly focused on cooling dominated buildings in a hot and humid region. A typical medium sized commercial office building located in South East Asia was chosen as the case study. The building was audited to analyse its energy performance and mapped out its end-use energy consumption. It was found that the building consumed 7,334,630 kWh energy a year where 87.5% of the energy were spent on supplying a good indoor comfort for the occupant (that involves air conditioning and lighting). A detail data from the building’s energy manager was used to build a baseline building model before thermal analysis, and further investigation was carried out to achieve ZECB. It was discovered that 84% of the building’s heat gain was emanated from internal sources and 16% from solar. In this study, a whole-building approach encompassing of all the three methods (passive cooling using phase change material, retrofitting procedure based on thermal analysis and combined heat power solar energy generation system) were applied to the target building as a retrofit means that resulted in a zero energy commercial building (ZECB). The methods if implemented is estimated to reduce 52.2% of the total energy consumption with the remaining energy requirement will be fully supplied by on-site solar energy generator. While 573,674.77 kWh excess electricity and 3,531,703 kWh excess cold energy will be supplied to the grid and neighbouring buildings. Parts of the suggested retrofit strategies were fully implemented by the case-study building in February 2016. It is found that the actual energy consumptions after retrofitting were reduced as predicted from the simulation. This proves that the developed methods from this research are applicable to the real world.