In the application of the deep borehole heat exchanger(DBHE),the pipe array is composed of multiple DBHEs and used for the building heating.In order to study the heat transfer performance of the coaxial DBHE array,a numerical model was established based on the typical geological distribution in Xixian New Area.The influence of the distance between the DBHEs and their distribution patterns was investigated on the thermal interaction and the attenuation of outlet-water temperature during the long-term heating period.The results showed that the'cold accumulation'of rock and soil around the DBHE was the main reason for the decline of the heating capacity of the DBHE array year by year.When the distance between the DBHEs increases from 5m to 25m,the average outlet-water temperature of the DBHE and the heat extraction power increased by 3.86%and 11.5%,respectively.Considering the geological distribution in Xixian New Area,the distance between the DBHEs should be kept above 15m.In the four types of DBHE array distributions(cross,circular,polyline,linear),the straight-line distribution exhibited the smallest attenuation in outlet-water temperature and heat extraction power.The outlet-water temperature of the central DBHE only decreased by 5.74%.In the engineering applications,it is necessary to avoid the overlapping arrangement of DBHEs and ensure that they are arranged in a straight line.
关键词
中深层地热/同轴地埋管/管群/换热/冷堆积
Key words
middle-deep geothermal energy/coaxial deep borehole heat exchanger/pipe array/heat exchange/cold accumulation
维普
万方数据