Potentials for CO2-neutrality through Energy-retrofit of the Existing Building Stock in 26 Cities in China.

China's building stock of more or less uniform residential blocks requires energy-, comfort and not at least architectural upgrade, if future demands are to be met and if demolition and thereby loss of valuable resources is to be prevented. Replacement of these buildings is not an option since affordable housing continues to be required in Chinese cities. Comfort requirements are currently increasing from previously undemanding behaviour to more energy-demanding comfort expectations. Retrofit of conditioning equipment in old buildings will lead to a significant increase in energy consumption, if the buildings are not upgraded (insulated, air tightened, etc.). Furthermore, although China is leading in the production of photovoltaic modules, the utilization of building integrated photovoltaic systems (BIPV) is not yet implemented at a significant scale. However, the prevailing building typology is characterized by a southerly orientation, a favourable floor-to-roof ratio, a rather simple building envelope, appropriate floor plans and not at least a roof structure able to carry PV systems. Climates in many areas in China are more favourable for solar energy generation than in other countries, such as Germany, where BIPV is already widely utilized. This paper investigates the potentials of energy upgrade of a building typology representative for a large percentage of the existing Chinese building stock for 26 climates in China. Strategies of “efficiency” (energy-upgrade measures), “consistency” (renewable energy generation and revitalisation of existing structures) as well as “sufficiency” (reduced comfort requirements) are discussed as the pillars of a strong concept for sustainable upgrade of China's existing building stock. [ABSTRACT FROM AUTHOR]