能源桩储热分析与数值模拟研究

发布时间：2018-02-28 21:24

本文关键词： 能源桩储热温度场数值模拟　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：近几年,我国经济不断发展,人们对居住的品质也越来越高,建筑的空调系统(供热和供冷)是人们生活所必须的,然而这部分能耗占到社会总能耗的25%~30%。在我国,大部分地区主要以煤炭能源作为供热资源,煤炭能源在燃烧的过程中会产生大量的有毒有害的气体,给环境带来一系列的问题。在各种新能源和可再生能源中,地源热泵系统是一种可持续的,环境友好的能源系统,利用地热能源供暖/制冷的建筑,符合绿色建筑设计要求[1]。地球的地表下中包含存储的地热能源的巨大潜力,地源热泵技术就是充分利用这种能量用于加热与冷却的一种建筑节能技术[2]。从90年代至今,地源热泵技术开始从全世界各地得到了大力发展与广泛应用。虽然地源热泵具备经济、节能、绿色环保等众多优点,但并非完美,其不足主要表现在三个方面:1.项目开始投入资金偏高,2.不合理的布置方式占用了地下空间,3.错误的排放方式污染地下水。本文对能源桩技术的储热进行了较为系统的分析,本文主要工作与研究成果如下:(1)总结了国内与国外关于能源桩技术的研究现状,同时介绍了能源桩目前存在的主要问题及研究价值;(2)分析了能源桩与周围土体之间发生热交换的热力学理论;同时分析了桩埋管换热器与混凝土及土壤之间的热传递过程,建立了热交换模型;(3)采用MIDAS/CIVIL有限元计算软件建立了有限元模型,分析了不同工况下对能源桩换热能力的影响,发现得入口水温与土壤环境温度相差越大,进出口温差越大,但最终热扩散半径相差不大;桩直径越大,桩的储热能力越强;同时桩直径为800mm时,管间距设置为400mm,桩储热最合理。(4)分析了“U”型与“W”型换热器换热性能对比试验,通过数值分析得出在相同工况下两种换热器的进出口水温、换热功率、土壤温度变化及热扩散半径随时间变化曲线,发现W型的换热性能优于U型,但经济性不如U型换热管。(5)分析了群桩模拟,在群桩储热效应下,每根能量桩的热影响半径能达到2m,这明显要比单桩的热影响半径大,说明群桩的热效应并非单桩的热叠加。
[Abstract]:In recent years, the economy of our country has been developing continuously, and the quality of people's living is getting higher and higher. The air conditioning system (heating and cooling) in buildings is necessary for people's daily life. However, this part of energy consumption accounts for 25% of the total energy consumption of society. In our country, Most areas mainly use coal energy as heating resources, coal energy will produce a large number of toxic and harmful gases in the process of combustion, which will bring a series of problems to the environment. The ground-source heat pump system is a sustainable, environment-friendly energy system that uses geothermal energy for heating / cooling buildings that meet the design requirements of green buildings [1]. Ground-source heat pump (GSHP) technology is a kind of building energy saving technology that makes full use of this energy for heating and cooling. Ground-source heat pump technology has been developed and widely used from all over the world. Although ground-source heat pump has many advantages, such as economy, energy saving, green and environmental protection, it is not perfect. The deficiency is mainly manifested in three aspects: 1.The project begins to invest too much money. 2. Unreasonable arrangement occupies underground space 3.The wrong discharge way pollutes groundwater. This paper makes a systematic analysis on heat storage of energy pile technology. The main work and research results of this paper are as follows: (1) summarizing the research status of energy pile technology both at home and abroad. At the same time, the main problems and research value of energy pile are introduced. The thermodynamic theory of heat exchange between energy pile and surrounding soil is analyzed, and the heat transfer process between pile buried tube heat exchanger and concrete and soil is also analyzed. The heat exchange model is established. The finite element model is established by using MIDAS/CIVIL finite element calculation software. The influence of different working conditions on the heat transfer capacity of energy pile is analyzed. It is found that the greater the difference between inlet water temperature and soil environmental temperature is, the greater the difference between inlet and outlet temperature is. But the final thermal diffusion radius is not different; the bigger the pile diameter, the stronger the heat storage capacity of pile; at the same time, when the diameter of pile is 800mm, the distance between pipe and pipe is set to 400mm, and the heat storage of pile is most reasonable. The comparative test of heat transfer performance of "U" type heat exchanger and "W" type heat exchanger is analyzed. Through numerical analysis, the curves of inlet and outlet water temperature, heat transfer power, soil temperature change and thermal diffusion radius with time are obtained under the same operating conditions. It is found that the heat transfer performance of W type is better than that of U type. But the economic efficiency is not as good as that of U-type heat exchanger pipe. (5) the simulation of pile group is analyzed. Under the heat storage effect of pile group, the thermal influence radius of each energy pile can reach 2 m, which is obviously larger than that of single pile, which indicates that the thermal effect of pile group is not the thermal superposition of single pile.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU83

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