Analysing the benefits and challenges of retrofitting rural dwellings in Hunan, China to the Passivhaus EnerPHit standard

Abstract

Chinese rural housing largely consists of uninsulated reinforced-concrete apartment blocks with poor energy performance. These dwellings are structurally sound, costly to demolish and challenging to recycle. Retrofit is, therefore, potentially more worthwhile than new build. Currently, there is no Chinese standard for retrofitting dwellings. This research examined the viability of applying the German EnerPHit retrofit standard to Chinese rural dwellings in Hunan, southern China (hot summers and cold winters). Dwellings were evaluated in terms of building structure, materials and systems, and a common type of apartment was selected. The real-world thermal performance of the dwelling was monitored and then the dwelling was modelled using the dynamic thermal simulation software DesignBuilder and Passivhaus Planning Package (PHPP). Monitoring data were used to validate the software’s predicted values. Next, energy-efficient EnerPHit retrofitting measures were incrementally applied to the dwelling model. Simulation results indicated that it was possible for the apartment to meet the EnerPHit standard if an optimised combination of thermal measures were applied. Good ventilation heat recovery was essential for winter comfort and minimum energy consumption; in summer, using adjustable shading and a high efficiency humidity recovery ventilation system was important. Appropriate natural ventilation schedules contributed in lowering cooling energy demand.