Experimental study on the thermal performance of underground cave dwellings with coupled Yaokang

The vernacular architecture of cave dwelling is known for its use of local building materials and traditional heating system (Yaokang) for a comfortable indoor environment. However, it has not been proved by a quantitative evaluation study so far. A seven days short-term on-site monitoring was thus conducted in winter for evaluating the thermal performance and heating potential of Yaokang. Experimental results and Kang heating potential coefficient (KPC) proposed here indicate that the average heat emission per unit area of the Yaokang is between 45 and 80 W/m2, giving energy saving of around 59.4% for cave dwelling in cold area of China. Additionally, to assess the long-term thermal response characteristic of underground cave dwellings, a two-years continuous remote monitoring was carried out. And the monitoring results show that the indoor air temperature of cave dwellings ranges from 9 °C to 17.4 °C in winter and from 22.8 °C to 26.7 °C in summer. Conclusions drawn from this study lay a theoretical basis for low energy building design.