非连续运行工况下垂直地埋管换热器的换热特性  

Heat exchange characteristics of vertical U-tube ground heat exchanger with discontinuous operation condition

作　　者：杨卫波[1] 施明恒[2] 陈振乾[2] 

机构地区：[1]扬州大学能源与动力工程学院,扬州225127 [2]东南大学能源与环境学院,南京210096

出　　处：《东南大学学报（自然科学版）》2013年第2期328-333,共6页Journal of Southeast University：Natural Science Edition

基　　金：广西建筑新能源与节能重点实验室(桂林理工大学)开放基金资助项目(11-03-21-15);"十一五"国家科技支撑计划资助项目(2008BAJ12B04);住房与城乡建设部科技计划资助项目(2008-K1-26);江苏省科技支撑计划资助项目(BE2010699);江苏省政府留学基金资助项目(2010年度);扬州大学"新世纪人才工程"优秀青年骨干教师计划资助项目(2008年度);扬州大学科技创新培育基金资助项目(2012CXJ047)

摘　　要：为了探讨非连续运行条件下地埋管的换热特性,基于相似理论搭建了地下换热模型试验台,进行了不同间歇运行工况的试验测试;建立了垂直U型埋管换热器二维非稳态传热模型,分析了单工况间歇运行、双工况交替运行及地下岩土类型对非连续运行条件下土壤温度分布特性的影响.结果表明:合理的间歇运行模式有利于埋管周围土壤温度快速恢复,从而可有效提高浅层地热能利用率;对于单工况间歇模式,等负荷强度变运停时间比时土壤温度恢复效果随间歇时间增加而增加;当放热量一定时,土壤温度波动较大,但并不一定能显著改善机组运行效果.对于双工况交替模式,均可显著降低土壤温升率,且间歇双工况交替比连续交替可增加全年土壤取放热不平衡率.此外,土壤导热系数与热扩散率越好,其温度恢复越快.实验表明:所建模型预测温度的计算值与实验值最大绝对误差为0.45℃,相对误差小于5%.In order to investigate the heat exchange characteristics of ground heat exchangers（GHE） with discontinuous operation condition,a model experimental apparatus of GHE was set up based on similarity theory,and the experiments were performed for different intermittent operation mode.A two-dimension transient heat transfer model was developed for the vertical U-tube GHE.The influences of single-operation condition intermittent mode（SCIM）,double-operation condition alternate mode（DCAM） and soil type on soil temperature distribution characteristics under discontinuous operation conditions were studied.The results indicate that a suitable intermittent operation mode can improve the soil temperature recovery effect（STRE） and thus the using efficiency of shallow geothermal energy can be enhanced.For SCIM,the STRE increases with the increase of intermittent time when the load intensity is constant and the time ratio of on to off is variable.However,the saving energy effect is not obvious because of a large soil temperature fluctuation when the total ground load is constant.For DCAM,a good STRE can be obtained,and the DCAM with intermittent time can have a larger imbalance rate for ground load,compared with that with continuous time.Additionally,the better the soil thermal conductivity and diffusivity,the faster the temperature recovery.The experimental validations show that for the developed model,the predicted maximum absolute error is 0.45℃ and the relative error is less than 5%.

关 键 词：地源热泵 地埋管换热器 非连续运行工况 换热特性 

分 类 号：TU83[建筑科学—供热、供燃气、通风及空调工程]