Evaluating the energy-saving potential of earth-air heat exchanger (EAHX) for Passivhaus standard buildings in different climates in China

The significance of constructing low-carbon buildings has been on the rise because of the growing public concern about global warming and energy prices. The Passive House (or Passivhaus) standard is widely applied throughout Europe to reduce building energy consumption. However, a large percentage of the world’s population lives in regions with not only heating demand in winter but also high cooling and dehumidification energy consumption in the hot and humid summer, such as in several regions in China. The energy consumption of buildings in these regions could not be reduced by designing or retrofitting the buildings to Passivhaus standard only, but applying appropriate low energy cooling and dehumidification technologies are also necessary. The earth-air heat exchanger (EAHX) system is a suitable solution for utilizing low-temperature soil in summer, but the performance of the EAHX system in different climates was not previously evaluated. Thus, this research aims to evaluate the energy-saving potential of the EAHX system in a multi-storey Passivhaus standard building in different cities in China with different climatic conditions. A model of the Passivhaus building with the EAHX system was developed and verified using the Passive House Institute (PHI) prediction tool, PHPP and the commercial building energy simulation tool, IES Virtual Environment (VE). The results have shown that the EAHX system achieved an annual building energy load saving of up to 12.8 kWh/m2 in regions with hot and humid summers and cold winters, such as Beijing and Shanghai. The present study shows the potential of the addition of the EAHX in enhancing the building performance to satisfy the Passivhaus standard in hot and humid climates.