A simplified calculation method for predicting the thermal performance of a burning cave in rural houses of Northern China

Burning cave is becoming more and more popular in rural areas of northern China. It also has some disadvantages such as uneven temperature distribution, partial higher temperature and lower thermal efficiency. In order to research the heat transfer performance of the burning cave, an unsteady heat transfer model has been established, and a theoretical calculation formula has been deduced and verified by experimental data. It shows that both the thermal characteristic of the radiant floor on the burning cave and the heat generated from different biomass fuels inside the burning cave have a large impact on the surface temperature and heat transfer of radiant floor. Moreover, while the heat transfer coefficient of the radiant floor was a constant, the surface temperature of the radiant floor changed with the heat released from different fuels was consistent with exponential variation form. However, as using the same biomass fuel, the thermal resistance of the radiant floor was increased by 0.5(m2 K)/W, the heat transferred from the burning cave to the heating room could be reduced to 0.67 times of the original heat before optimized. Therefore, the valid theoretical analysis calculation formula could provide theoretical support for reasonable design on a burning cave, and predict thermal performance on different types of burning caves more easily.