Mitigating the vicious cycle between urban heatwaves and building energy systems in Guangdong–Hong Kong–Macao Greater Bay Area

<p>Urban heatwaves, existing in building neighborhoods, are harsh microclimate phenomena caused by human activities. With global warming and urbanization, exacerbated urban heatwaves are increasing energy-supply burdens and operational risks for building energy systems. At this point, a typical vicious cycle exists among urban microclimate, building energy systems, and cooling equipment, especially in high-density building blocks. Thereby, we propose a joint optimization model to quantify this vicious cycle by combining the urban canopy layer model, urban surface layer model, building energy model, and cooling equipment efficient model. Furthermore, optimal building energy system operation strategies are provided to mitigate the vicious cycle, by utilizing building thermal inertia and arranged building pre-cooling. Case studies are implemented in three typical cities in the Guangdong-Hong Kong-Macao Greater Bay Area in China, including Macao with high population density, Kowloon in Hong Kong with high-rise buildings, and Nanshan in Shenzhen with high-density urban villages. The results demonstrate that the vicious cycle raises urban canopy temperature by 0.97-2.09°C, which correspondingly increases building cooling energy consumption by 1.6-8.4 W/m<sup>2</sup>. By mitigating this vicious cycle based on the proposed optimization model, the energy-saving potential of building blocks can reach 11.2%, 13.4%, and 12.3%, and save <styled-content style-type="number">1116.5</styled-content> MWh, <styled-content style-type="number">1724.71</styled-content> MWh, and 823.23 MWh in the three typical areas, respectively.</p>