太阳能制冷在多年冻土热稳定维护中的传热效果研究

Study on Effect of Heat Transfer about Maintenance of Thermal Stability with Solar Cooling in Permafrost

确保多年冻土地基的长期热稳定仍然是当前冻土学科研究的重点和难点。科研人员长期致力于冻土工程关键技术的研究,研发了维护多年冻土地基热稳定的太阳能制冷技术及太阳能制冷装置,以太阳能热能为动力,实现制冷装置不分季节的全时段工作,特别是在暖季,能够有效阻止环境温度对多年冻土地基的热侵蚀。现场试验研究表明:采用该技术及制冷装置后,年均地温较天然年均地温有较大幅度的降低,降温幅度为-2.23^-3.9℃,且呈逐年增大的趋势;多年冻土的上限埋深由2.0 m抬升至1.5 m;季节活动层中的制冷影响半径由0.76m扩大至2.56m,多年冻土层中的制冷影响半径最大达到了3.95 m;实际制冷量为所需估算制冷量的2.27倍。总体上,采用维护冻土地基热稳定的太阳能制冷技术及其制冷装置后,季节活动层和多年冻土层的温度大幅度降低,上限埋深明显抬升,有效地维护了多年冻土的热稳定,具有较大的研究价值和应用前景。

At present,ensuring the thermal stability of permafrost foundation is the key point and difficulty in the study of the discipline of permafrost.Having long been committed to the research of the key technology of frozen soil engineering,researchers have developed solar cooling technology and devices for the maintenance of thermal stability in permafrost regions.By using the solar energy as heat source power,the cooling device could work full time in all seasons,especially in the warm season to prevent thermal erosion of permafrost foundation from the temperature of environment.Field test results show that the annual average ground temperature is significantly lower than the natural annual ground temperature with the use of the refrigeration device.The temperature increases ranging from-2.23 ℃ to-3.9 ℃,showing a decreasing trend year by year.In addition,the upper limit depth of permafrost burial changes from 2.0 mto 1.5 m.The effect radius of cooling is expanded from 0.76 mto 2.56 min a season active layer and the maximum effect radius of cooling reached 3.95 m in a layer of permafrost.On the other hand,the actual cooling capacity is about 2.27 times than the estimated amount of cooling capacity.To conclude,the temperature of seasonal active layers and permafrost layers is greatly decreased and the upper depth limit of permafrost burial is raised up obviously with this technology and cooling device,resulting in effective maintenance of the thermal stability of permafrost.The technology deliversagreat research value and application prospect for practical engineering.