冷热负荷不平衡地区地热换热器设计及其运行对策
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摘要
为提高冷热负荷不平衡地区使用地源热泵系统后地下温度场的均匀性,以36个钻孔组成的地埋管管群,冷热负荷比为2. 5∶1. 0,运行期20年为例,提出了3种外密内疏的分区优化埋管布置方式.仿真结果表明:地埋管中心区域布管数量相对稀疏,有利于减小温度场的温度梯度,提高温度场的均匀性,边界区域过余温度相比传统的均匀布管方式略有提高,能有效降低中心区域温度场的波峰现象,此外,土壤热扩散系数越小,采用中间布管稀疏、外围布管紧密的优化设计方案的效果愈加明显,验证了外密内疏管群优化布置方案的可行性.
To improve the uniformity of underground temperature after using ground source heat pump system,three optimal layouts of 36-borehole heat exchangers( BHE) were proposed for area with an unbalanced cooling/heating load ratio of 2. 5 ∶ 1. 0 and an operation duration of 20 years. Results show that the less the BHEs are located in the center of drilling area,the more uniform the temperature field with the less temperature gradient will be. The surrounding underground excess temperatures of the optimal layouts are slightly higher than that of the traditional layout and the peak values of the temperature field can be reduced. Additionally,the effect is more significant when applied to the area with small thermal diffusivity. The feasibility of the proposed optimal BHE layout are verified.
To improve the uniformity of underground temperature after using ground source heat pump system,three optimal layouts of 36-borehole heat exchangers( BHE) were proposed for area with an unbalanced cooling/heating load ratio of 2. 5 ∶ 1. 0 and an operation duration of 20 years. Results show that the less the BHEs are located in the center of drilling area,the more uniform the temperature field with the less temperature gradient will be. The surrounding underground excess temperatures of the optimal layouts are slightly higher than that of the traditional layout and the peak values of the temperature field can be reduced. Additionally,the effect is more significant when applied to the area with small thermal diffusivity. The feasibility of the proposed optimal BHE layout are verified.
引文
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[15] ZENG H Y,DIAO N R,FANG Z H. Efficiency of vertical geothermal heat exchangers in the ground source heat pump system[J]. Journal of Thermal Science,2003,12(1):77-81.
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[3] MOEL M, BACH P M, BOUAZZA A, et al.Technological advances and applications of geothermal energy pile foundations and their feasibility in Australia[J]. Renewable Sustainable Energy Review,2010,14:2683-2696.
[4]尚妍,李素芬,代兰花.地源热泵间歇运行地温变化特性及恢复特性研究[J],大连理工大学学报,2012,52(3):350-357.SHANG Y,LI S F,DAI L H. Study of characteristics of soil temperature variation and recovery under intermittent operation of ground source heat pump[J]. Journal of Dalian University of Technology,2012,52(3):350-357.(in Chinese)
[5]陈进,徐菱虹,胡平放.混合式地源热泵系统间歇运行研究[J],太阳能学报,2014,35(7):1138-1143.CHEN J,XU L H,HU P F. A study on intermittent operation of hybrid ground source heat pump system[J].Acta Energiae Sloaris Sinica,2014,35(7):1138-1143.(in Chinese)
[6]金光,王正文,吴晅,等.混合式土壤源热泵系统的研究现状及展望[J],流体机械,2016(2):82-87.JIN G,WANG Z W,WU X,et al. Research status and prospect of hybrid ground source heat pump systems[J].Fluid Machinery,2016(2):82-87.(in Chinese)
[7] CHEN X,YANG H X. Performance analysis of a proposed solar assisted ground coupled heat pump system[J].Applied Energy,2012,97:888-896.
[8] ANDRES M, LUIS A, BUJEDO C, et al. Influence parameters on the performance of an experimental solarassisted ground-coupled absorption heat pump in cooling operation[J]. Energy and Buildings,2013,66:282-288.
[9] PETER P,OLIVER M,JONAS W,et al. Investigations and model validation of a ground-coupled heat pump for the combination with solar collectors[J]. Applied Thermal Engineering,2014,62:375-381.
[10]高承苗,刁乃仁,石维群,等.工业余热在改善冬季地源热泵系统运行中的应用[J].建筑热能通风空调,2012,31(3):50-52.GAO C M,DIAO N R,SHI W Q,et al. The application of industrial waste heat to improve the ground-source heat pump system[J]. Building Energy&Environment,2012,31(3):50-52.(in Chinese)
[11]车文昊,白莉,常文涛,等.地埋管管群非等间距布置对管群土壤温度场及热通量的影响[J].吉林建筑大学学报,2015,32(5):31-34.CHE W H,BAI L,CHANG W T,et al. The effects of non-equidistant arrangement of buried pipes on the soil temperature field and heat flux[J]. Journal of Jilin Jianzhu University,2015,32(5):31-34.(in Chinese)
[12]于明志,张凯,胡爱娟,等.减缓地下冷/热量累积效应的集群地埋管分区运行方法研究[J].太阳能学报,2016,37(10):2593-2599.YU M Z,ZHANG K,HU A J,et al. Zoning operation method for retarding cold/heat accumulation effect of cluster underground pipes[J]. Acta Energiae Sloaris Sinica,2016,37(10):2593-2599.(in Chinese)
[13] ZENG H Y,DIAO N R,FANG Z H. A finite line-source model for boreholes in geothermal heat exchangers[J].Heat Transfer Asian Research,2002,31(7):558-567.
[14]杨卫波,施明恒.基于线热源理论的垂直U型埋管换热器传热模型的研究[J].太阳能学报,2007,28(5):482-488.YANG W B,SHI M H. Study on heat transfer model of vertical U-tube ground heat exchangers based on line heat source theory[J]. Acta Energiae Solaris Sinica,2007,28(5):482-488.(in Chinese)
[15] ZENG H Y,DIAO N R,FANG Z H. Efficiency of vertical geothermal heat exchangers in the ground source heat pump system[J]. Journal of Thermal Science,2003,12(1):77-81.