基于土壤自然冷能桥面冷却系统的可行性研究

FEASIBILITY STUDY ON BRIDGE DECK COOLING SYSTEM USING NATURAL GROUND COOLING ENERGY

在现有土壤源热泵桥面热力融雪的基础上,提出夏季直接利用地下自然冷能冷却桥面的新理念。通过耦合桥面冷却模型和地下埋管换热模型,建立了基于土壤自然冷能桥面冷却系统的数学物理模型,并利用有限单元法进行了数值求解。对北京某桥面有无冷却时的桥面温度、地下换热器单位孔深负荷及单位桥面积吸热量、地下换热器孔壁温度进行模拟与分析。模拟结果表明:路面温度超过60℃的时间减少88%,55～60℃的时间减少45%.地下钻孔壁温约升高3.9℃,证明该系统夏季可以有效减少桥面高温时间,冬季有助于改善融雪系统运行效果。

Based on the existed bridge deck hydronic snow-melting system using ground source heat pump, a new concept of using natural ground cooling of thermal energy directly to lower the upper surface temperature of bridge deck in summer was presented in the paper. Mathematical and physical model of such cooling system was developed by coupling bridge deck cooling sub-model and geothermal heat exchanger sub-model. Its nemerical solution in two-dimensional transientstate was obtained by using finite-element analysis method. The parameters, such as the upper surface temperatures of the bridge deck in Beijing with cooling or not,cooling load of unit hole depth for geothermal heat exchanger, absorbing heat for unit surface of a bridge, and hole wall temperature of geothermal heat exchange were analyzed using the model. Resuits indicate that the hours of deck temperature above 60℃ and between 55-60℃ were reduced 88% and 45%, respectively, and the temperature of hole wall was increased by 3.9℃. Therefore, this system not only can decrease the hours of high temperature on the bridge deck surface in summer effectively, but also can improve operational performance of snow-melting system in winter.