基于土壤热平衡问题的土壤源热泵理论与实验研究

项目名称： 基于土壤热平衡问题的土壤源热泵理论与实验研究

项目编号： No.50806052

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 范蕊

作者单位： 同济大学

项目金额： 21万元

中文摘要： 为了实现土壤源热泵系统在冬夏负荷差异较大地区的科学合理应用，避免出现土壤逐年温升/降而影响系统效率问题，本课题主要针对夏季负荷占优地区、土壤源热泵系统的热平衡问题展开研究。好的模型是理论研究之本，因此研究者首先完善了地下埋管换热器的热渗耦合传热模型；基于此，对系统运行特性的众多影响因素进行了单因素及多因素的敏感性分析，并利用SPSS回归方法得到了单位井深换热量、换热井出口水温与各因素之间的线性或非线性的关系式，从而简化了复杂的初步设计阶段，便于工程采用；然后，针对滩涂水岸这种地下水丰富地区进行了分析，明确了地下水相关参数对系统的影响；接下来又利用trnsys模型对土壤热平衡问题展开了研究，明确了负荷比、间距、深度、土壤热物参数等对热平衡的影响，并从复合式系统、地埋管分排运行等角度提出了缓解土壤热平衡的思路，研究成果直观，便于工程及其他学者参照；此后，又提出了浅层土壤蓄热能的理论并对其资源量进行了分析，提出了土壤源热泵系统的设计方法；最后，结合实际项目建立了土壤源热泵系统的实验平台，初步实验研究也验证了浅层土壤蓄热能的理论，后续将结合该实验台就土壤蓄能展开长期的研究以解决热平衡问题。

中文关键词： 土壤源热泵；热平衡；热渗耦合传热模型；回归分析；资源量分析

英文摘要： For the better development of Ground source heat pump (GSHP) system in China especially in cooling load dominated area, the soil thermal imbalance problem is focused on in this paper that is a big obstacle to block the application of GSHP system. The coupled heat conduction and heat advection model for ground heat exchanger (GHE) is done in the first step to consider the impact of ground water flow. And then based on the model, we would like to make sure the operation performance of GSHP system reacting to variable parameters such as soil heat conductivity, specific heat capacity, borehole diameter and so on. The relationships between heat transfer quantity per meter borehole and various factors had been arrived by Statistical Product and Service Solutions (SPSS) which is good for the practical application by engineers and researchers. Specifically, the impact of ground water flow on heat transfer of GHE in wet-land area is analyzed next. After that, it is very meaningful to make sure heat imbalance problem in soil. So from the perspective of load profile, borehole distance, borehole depth, soil thermal conductivity and specific heat capacity etc., we will see the heat imbalance condition such as soil temperature rise or drop after 10 years running. And then hybrid system and optimized alternative pipe row operation are suggested to be used to eliminate or solve the soil heat imbalance to a certain degree. Furthermore, the utilizable shallow soil thermal storage energy amount is estimated for GSHP use and then a useful design methodology for GSHP system based on the theory is presented as the result. Finally, the preliminary experimental research is done after the construction of the hybrid ground source heat pump system with cooling tower which is also a practical project. The result is consistent with shallow soil thermal storage energy theory too. The long term experimental research for soil energy stored is the future study after this project. The research results here help us to make sure the soil thermal imbalance problem and then figure out the solutions, which is very useful for the good development and application of GSHP system.

英文关键词： Ground source heat pump; thermal imbalance;coupled heat conduction & advection model; regression analysis; utilisable resource amount