地埋管换热器形式、管径及岩土温度对其换热性能的影响

Influence of loop type,pipe diameter and soil temperature on performance of ground heat exchangers

建立了单U形与双U形地埋管换热器的三维数学模型。对外径25mm与32mm的单U形与双U形地埋管换热器换热性能的模拟研究表明,相同管径双U形地埋管换热器比单U形地埋管换热器换热量提高20%左右,但外径25mm的单U形地埋管换热器可以获得更大的进出口温差;对于双U形地埋管换热器,外径32mm与25mm相比,换热性能无明显优势;工程应用中,在地埋管用地面积充足时,建议选用外径25mm的单U形地埋管换热器,否则应选用外径25mm的双U形地埋管换热器;岩土温度每升高1℃,出口水温升高0.23℃,换热量下降5%左右。

Establishes a three-dimensional mathematic model for single U-and double U-type groundheat exchangers, and researches the heat transfer performance of the two type ground heat exchangers with the pipe diameter of 25 mm and 32 mm. The results show that the heat exchange Of the double U-type ground heat exchanger increases by 20% than that of the single U-type ground heat exchanger with the same pipe diameter, but the single U-type ground heat exchanger of 25 mm diameter will achieve larger water temperature difference between inlet and outlet; for the double U-shaped ground heat exchanger of 32 mm and 25 mm diameter, the former has not more significant advantage than the latter; for an actual project, if the area of land to be occupied is sufficient, the single U-type ground heat exchanger of 25 mm diameter is preferable, otherwise the double U-type ground tieat exchanger of 25 mm diameter should be selected; when the soil temperature increases by 1 ℃, the outlet water temperature increases by 0.23 ℃, and the heat exchange decreases by 5%.