Passive house renovation in Zhuhai
A flagship renovation project for passive house standards in subtropical climate zones
For the first time ever a total overhaul will be undertaken in the South Chinese city of Zhuhai to meet passive house standards in a subtropical climate. The German architecture firm Frey Architekten will lead the project in Zhuhai, assisting with its development and implementation. Regarding innovative sustainable technology, ecology and economy, the award-winning concept is a flagship project with a global impact in the area of passive house renovations in temperate climes. The densely populated residential and commercial district spans 21.25 acres for the renovation, which will rely on 24 sustainable types of technology.
In light of the local climate conditions, the high demand for cooling and dehumidifying (compared to the low demand for heat) will play a central role. The existing buildings will be renovated according to the so-called “Four-Step-Protection-Principle” from which the following strategies for energy efficiencies for passive cooling will emerge:
- Well-shaded curtain walls that insulate against direct sun rays and reduce the energy demand for air-conditioning;
- Provision of interior thermal comfort through heat insulation and cold storage from the external shell;
- Nocturnal cooling through natural ventilation;
- Heat-storing construction of the interior surface that balances out the warmth produced during the daytime.
The following passive techniques will be used:
- Natural ventilation from the inner courtyard that draws out the warmth from the interior rooms;
- Utilisation of WRG and dehumidifying components in the ventilation system;
- Underground heat pump using water as a cooling element;
- Double-paned Low-E-Windows and heat conductivity of about 2.0 W/ (m2K);
- Heat-reflecting construction materials on the exterior surface;
- Verdant facades and roof-tops for thermal protection and shading;
A photovoltaic system with 252 kW was installed that covers the majority of the power demand for lighting, ventilation, living, etc. Thirty wind turbines have also been implemented to leverage local climate and energy resources. After taking these measures, the demand for cooling and dehumidifying sank 50 per cent, energy demand decreased by 539,999 kWH and the primary demand for energy was reduced by 60 per cent annually.
With the help of the verdant facades, the water filters and the monitoring system, between 80,000 and 140,000 gallons of waste water are regenerated daily. Rainwater from the buildings and streets is filtered by water-permeable panels and absorbed by the plants for reuse.
In summary, the impact of the renovation efforts:
- CO2 emissions have been reduced by 60 per cent (that equals 280 tons annually);
- 47 per cent of the overall energy demand is covered by 17,115 square feet of photovoltaic modules, which produce 254,000 kWh of electricity annually;
- The annual maintenance costs are reduced b y 517,000 CNY with an amortisation of 19 years