摘要
中深层地热能现已成为地热能开发利用的重点内容。文章基于实验测试,得到初始土壤温度分布及深井换热器进、出口温度变化情况,分析了中深层地热热泵供暖系统的供热特性。开发了一种二维深井换热器传热模型,考虑了实测地温梯度以及井底流动与传热过程,具有较高的计算精度。依据模型研究了内管管长,循环流量及管内流向对深井换热器传热特性的影响。结果表明:深井换热器内管管长由1890 m增至1950 m时,其取热能力增加2%~7%;循环流量为11.25~56.25 m^(3)/h时,深井换热器取热量随循环流量的增加先升高再降低,同深度处内管与环腔流体温差随循环流量的升高而降低,流体随埋深的温度变化率随循环流量的升高而降低;深井换热器环腔进水内管出水比内管进水环腔出水时取热性能更优但其热短路现象更为严重。
Mid-deep geothermal energy has now become the focus of the development and utilization of geothermal energy.Based on experimental tests,this paper obtains the initial soil temperature distribution and the temperature changes at the inlet and outlet of the deep well heat exchanger,and analyzes the heating characteristics of the mid-deep geothermal heat pump heating system.A two-dimensional deep well heat exchanger heat transfer model is developed,which takes into account the measured geothermal gradient and the bottom hole flow and heat transfer process,and has high calculation accuracy.According to the model,the influence of the inner tube length,circulation flow rate and inner flow direction on the heat transfer characteristics of the deep well heat exchanger is studied.The results show that as the length of the inner tube of the deep well heat exchanger increases from 1890 m to 1950 m,its heat extraction capacity increases by 2%to 7%;When the circulation flow is 11.25-56.25 m^(3)/h,the heat extraction of the deep well heat exchanger first increases and then decreases with the increase of the circulation flow.The temperature difference between the inner tube and the annular cavity fluid at the same depth decreases with the increase of the circulation flow.The temperature change rate of the buried depth decreases with the increase of the circulating flow;The water outflow of the inner pipe of the annular cavity of the deep well heat exchanger has better heat extraction performance than the inner pipe of the annular cavity of the inner pipe,but the thermal short circuit phenomenon is more serious.
作者
刘福强
施志钢
蔡超
刘德民
董作敏
景登岩
Liu Fuqiang;Shi Zhigang;Cai Chao;Liu Demin;Dong Zuomin;Jing Dengyan(Qingdao University of Technology,Qingdao 266033,China;Dongfang Electric Machinery Co.,Ltd.,Deyang 618000,China;Qingdao Happiness Source Heating Company,Qingdao 266316,China)
出处
《可再生能源》
CAS
CSCD
北大核心
2023年第7期891-898,共8页
Renewable Energy Resources
基金
德阳市揭榜挂帅重大攻关项目(2022JBZG002)。
关键词
中深层地热热泵供暖系统
深井换热器
内管管长
循环流量
管内流向
middle-deep geothermal heat pump heating system
deep well heat exchanger
inner tube length
circulation flow
flow direction in pipe
