The aim of the “City Openings” research project is to develop an opening system to improve natural ventilation in Hong Kong’s high-rise buildings. The problem: in recent years, there is a trend amongst residents of modern residential buildings in tropical metropolises to use split system air conditioning systems. Use and energy consumption of such systems in those regions are enormous and the latter represents a major disadvantage in the utilisation of air conditioning systems. In the seven-million metropolis Hong Kong alone, additional energy consumption through air conditioning is estimated at 6.8 GW⋅h per year. With a population of 150 million, China’s south-eastern coastal region requires energy amounting to 145 GW⋅h annually to cool residential units by means of air conditioning systems. At the same time, hot waste air from split air conditioning systems additionally heats up the urban environment. Air conditioning systems emit 40% cooling energy in the form of heat to the ambient air, thus further exacerbating the heat island effect. However, it seems possible to improve comfort and simultaneously reduce mechanical ventilation by applying specific natural ventilation methods in residential buildings in subtropical zones. Research has shown that natural ventilation could enhance the comfort of Hong Kong dwellings by up to 85%, although air pollution is proving to be problematic in that respect. The aim will therefore be to develop a façade opening system that filters contaminated air while also meeting the requirements of a well-functioning natural ventilation. To that end, Hong Kong was selected as a subtropical climate zone location together with the according weather data. Hong Kong is seen as a precursor of innovative implementations in residential housing throughout mainland China. Hence, it is expected that European basic knowledge and innovative developments will be of great use to metropolises in China.
Roger Riewe, Institute of Architecture Technology, TU Graz
Ferdinand Oswald, Institute of Architecture Technology, TU Graz
Housing Authority Hong Kong