Potentials of Energy Efficiency and Generation Strategies for High-rise Office Buildings in Hong Kong

Abstract

Office buildings are a major building type responsible for a large proportion of the total electricity consumption in Hong Kong where most office buildings are high-rise due to the scarce developable land resources. There are more limitations to the selection of energy saving strategies for high-rise office buildings compared with low or medium ones, as high-rises are associated with more complex design on the fabric, envelope and service systems. It is therefore vital to explore measures for reducing energy consumption of high-rise office buildings. This paper aims to examine the potential of energy efficiency and generation strategies for high-rise office buildings in Hong Kong, and to develop scenario-based design strategies. A reference building model was first established using a typical real-life high-rise office building in Hong Kong. Using the reference building, the energy consumption was estimated with the aid of the energy simulation tools DesignBuilder and EnergyPlus. The potential of various energy saving and generation strategies was then investigated using the reference building and the tools. The strategies included chiller system selection, daylighting control, cooling setpoint temperature, PV system, and wind system. The results show that adopting water-cooled HVAC type and daylighting control system can reduce approximately 10% and 11% of the total energy consumption, respectively. The cooling setpoint was found to lead to an energy use saving by 4%. The use of PV systems was found to offset 4% of the total building energy use. The wind turbine however was found to have little effect on energy efficiency. The strategies together can help achieve up to 30% of building energy use reduction, yielding an optimised scenario. The findings inform future high-rise energy use parametric research and are useful to engineers for designing energy-efficient office buildings. Future research should also explore building fabric measures in order to maximise energy reduction potential.