成都某综合交通枢纽浅层地源热泵地埋管热物性分析与系统评价

System Evaluation and Thermal Physical Properties Analysis of Shallow Ground Source Heat Pump Buried Pipes in a Comprehensive Transportation Hub in Chengdu

基于成都某综合交通枢纽南北场咽喉区开展地质勘察数据,并对其开展岩土热响应试验分析与评价。地勘结果表明,工程区地下水类型主要为基岩裂隙承压水,地下水的渗流作用加强了热量交换速率,使测试得到的岩土体的综合热换功率值偏大,地下水对地埋管式地源热泵系统的运行较为有利。工程区的岩土体双U平均导热系数平均值为:2.45~2.78W/(m·K),所在地的岩土体(深度110m内)初始平均温度为18.32℃。各试验孔中,双U形式的地埋管换热功率均大于单U形式的热换功率,换热功率提高约22%。从测试效果和经济角度出发,结合四孔联合测试工况,建议选用双U25地埋管,夏季标准工况释热能力为42.89W/m,冬季标准工况取热能力为-42.66W/m。全年动态负荷计算分析结果表明,站房部分由可再生能源提供的空调冷热负荷比例可达32.1%,枢纽部分由地源热泵系统提供的空调冷热负荷比例可达21.5%。该研究成果可为在轨道交通领域推进浅层地热能利用提供可靠的技术路线及理论依据。

In this paper,geological investigation is carried out in the throat area of the north and south field of a specified comprehensive transportation hub and the geotechnical thermal response test is analyzed and evaluated.The geological survey results show that the groundwater in the project area is mainly confined water in bedrock fractures.The seepage effect of groundwater strengthens the heat exchange rate,which makes the comprehensive heat transfer power value of the rock and soil mass obtained by the test larger.The groundwater is more favorable to the operation of the buried piped ground source heat pump system.The average double-U thermal conductivity of rock and soil mass in the engineering area is 2.45~2.78W/(m·K),and the average initial temperature of rock and soil mass in the site(within 110m depth)is 18.32℃.In each test hole,the heat transfer power of the double-U buried pipe is greater than that of the single-U buried pipe,and the heat transfer power is increased by about 22%.From the point of view of test effect and economy,combined with the four-hole joint test condition,it is suggested to choose dual buried U25 pipe,the heat release capacity of the standard condition in summer can reach 42.89W/m,and the heat recovery capacity of the standard condition in winter can reach-42.66W/m.The annual dynamic load calculation and analysis results show that the proportion of air conditioning heating and cooling load provided by the ground source heat pump system can reach 32.1%in the station part and 21.5%in the hub part.This area is rich in shallow geothermal energy resources,and the test data can provide theoretical basis for the later design.