Cold energy storage performance of elevated pile-slab structure with automatically opening and closing dampers in permafrost regions

With global warming and increased human activities, permafrost degradation has intensified. A novel air-cooled structure, the elevated pile-slab structure with automatically opening and closing dampers, was proposed to face climate warming on permafrost. The thermal response of the structure under two ventilation modes and four different elevation heights was explored under the permafrost roadbed of the Qinghai-Tibet Plateau. The results indicated that the structure demonstrated superior cooling effects, compared to traditional roadbed. The cold energy utilization rate and cold energy storage capacity both gradually increased with the elevation height. However, the cold energy utilization rate was higher under the year-round ventilation mode, with the windward slope achieving a maximum of 81.9 % after one cold season. Contrarily, the cold energy storage capacity was stronger under the warm-season closure mode. When the elevation height reached 0.4 m, the cumulative cold energy at the depth of 3 m of the roadbed center reached 6.46 MJ/m3 over 50 years. Additionally, as the elevation height increases, the difference in cold energy utilization rate and cold energy storage capacity between the both slopes of the roadbed gradually decreased. Appropriately increasing the height can mitigate the asymmetry on both sides of the roadbed.