预埋与绑扎埋管形式能量桩传热特性研究

Thermal response of energy piles with embedded tube and tied tube

预埋钢管能量桩是一种新型桩埋管形式的地源热泵技术,然而,针对其特殊埋管形式下传热特性的研究却相对较少。针对预埋钢管单U型埋管能量桩的传热管-钢管-混凝土-桩周土的传热特性开展模型试验和数值模拟研究,测得在热-冷循环温度荷载作用下预埋钢管单U型埋管能量桩桩体及桩周土体的温度变化规律;为了对比分析,同时开展了传统绑扎单U型埋管能量桩的传热特性模型试验,并分析了预埋钢管能量桩的适用性。研究结果表明,预埋钢管能量桩的传热性能略低于绑扎埋管能量桩的传热性能;夏季工况两种埋管形式能量桩桩体温度和桩周土体温度最终变化量分别相差23%和16%左右;冬季工况该数值约为14%和18%左右。

The energy pile with embedded steel tube is a new type of ground source heat pump（GSHP） technique in the form of pipe-coupled pile. However, there are few studies focused on thermal response of this new pipe form. Experimental test and numerical simulation were conducted to study the heat transfer from tube to steel tube, to concrete, and to soil of energy piles with single U-shaped embedded steel tube. Temperature variations of surrounding soil and pile shaft under temperature loading of heating-cooling cyclic were measured. The thermal response of the ordinary single U-shaped heat exchanger energy pile with tied tube was also tested for comparative analysis. Finally, the applicability of energy pile with embedded steel tube was analyzed. The results show that the thermal response of energy pile with embedded steel tube is slightly lower than that of energy pile with tied tube. The final temperature of surrounding soil and pile shaft of two types of energy pile varies 23% and 16% in summer, and 14% and 18% in winter.