Challenges in the low-carbon adaptation of China’s apartment towers

Abstract

Low-carbon building retrofit will contribute to delivering China's policy to reduce carbon emissions. This paper proposes viable low-carbon adaptation strategies for a recurrent building type within the Hot Summer and Cold Winter (HSCW) zone. An existing 23-storey tower in Hangzhou is investigated within the context of a representative city environment. Indoor air temperatures and energy consumption were monitored across a typical floor and simulated in EnergyPlus. Outdoor and indoor airflow patterns were modelled in an advanced computational fluid dynamics (CFD) tool, FLUIDITY. Across a typical floor, observations and modelling show marked variations. Southfacing flats overheat significantly in summer largely due to solar radiation. External sun-shading structures are proposed and evaluated to counter summer overheating. An innovative wind catcher and exhaust-stack natural ventilation system is proposed to enhance indoor thermal comfort using natural ventilation. Modelling of this integrated ventilation system indicates that the proposed retrofit system will improve indoor thermal comfort even in the lower floors. The proposed building retrofit strategy is costed using locally established construction cost estimates. Predicted energy savings suggest that the adaptation strategy proposed is potentially viable with significant implications for policy-makers, developers, constructors and designers in this challenging climate zone in China.

A spatial-and-temporal-based method for rapid particle concentration estimations in an urban environment

“…The physics-based model, normally the numerical model of particle dispersion, simulates the dispersion process based on basic computational fluid dynamics (CFD) theory and the mass transfer mechanism; it demands sufficient knowledge of microclimate conditions, particle emission sources and the explicit description of physical deposition and chemical transformation processes (Lateb et al, 2016;Li et al, 2006). This method is mostly used to analyse the pollutant dispersion around buildings from certain known sources (Ai and Mak, 2013;Short et al, 2018). Several studies that have used CFD techniques to predict pollutant concentration have focused on the street canyon (Blocken et al, 2012;Tominaga and Stathopoulos, 2011;Vicente et al, 2018).…”

Revealing the Impacts of Passive Cooling Techniques on Building Energy Performance: A Residential Case in Hong Kong

“…Compared with the active solutions, the passive designs generally require less life cycle cost [18], and present more significant energy-saving effects [19] as well as longer lifespans. For example, a proposed passive adaption solution for a residential case showed an 8.18-year payback and a carbon dioxide emission reduction of 11.674 million kilograms [20]. Essah et al [21] reported a passive design solution for a residential case in Beijing, which reduced the working time of the mechanical heating and cooling system by half, thereby saving 50% of energy consumption.…”

The hot summer-cold winter region in China: Challenges in the low carbon adaptation of residential slab buildings to enhance comfort

“…The term 'slab' becoming a shorthand descriptor of the wide frontage, linear, medium-rise apartment blocks devised by post-war International Style modernist architects worldwide out of Le Corbusier's 1952 Unite block in Marseilles. Adaptation schemes for 'tower' building types are reported in [6].…”

“…Several solutions can be considered to retrofit existing buildings and reduce their energy consumption as well as their CO2 emissions. To cite only the main ones: the modification of the building envelope and/or the windows ( [7], [8], [9], [10]), the use of natural ventilation ( [1], [6], [8], [10], [11], [12]) and the use of sun-shading ( [6], [7], [11]) are known as efficient solutions.…”

“…Chimneys (stacks) consist of a vertical space to create a passage for facilitating air circulation towards the outdoor ( [11], [15], [16], [17], [18], [19], [20]) helping to improve the indoor thermal comfort during hot summers ( [15], [17]), while reducing the air-conditioning energy consumption [17]. Three cylindrical stacks, each of them linked to seven floors of a tower building located in Hangzhou, have been presented in [6] with promising efficiency in enhancing the natural ventilation flows. Windcatchers ( [21], [22]), predominantly located on the roof, are also an efficient way to enhance the natural ventilation in a building by channeling fresh outdoor air into a room ( [23], [24], [25]).…”