摘要
摘 要
能源是推动社会进步和人类赖以生存的物质基础。近 100 年来,全球能源消
耗平均每年以 3﹪的速度递增,大量能源的消耗,同时带来了十分严重的环境问
题,如气候变暖、生态破坏、大气污染等。这一切都严重制约着人类社会、经济
活动的发展。我国能源与环境状况更是如此。开发新能源、提高能源利用率、利
用节能技术已成为全球的迫切需要。随着经济高速增长和人民生活水平的提高,
人们对工作和生活环境提出了更高的要求,采暖、通风和空调用能也随之急剧增
长,并导致电网负荷峰谷差进一步增大。利用蓄热装置来协调热能供求在时间和
强度上的不匹配是经济和可行的办法。研制应用于空调领域的蓄热设备能够将用
电低谷期廉价的电能转化为热能储存起来,在用电高峰期再将这部分储存的热能
释放出来,以减少高峰期用电量,实现“削峰填谷”,这样做不仅大大节约了空
调运行费用,也减轻了电网负担,使用电时段的分配更加合理。因此研制空调用
蓄热装置具有重大的现实意义和广阔前景。
本研究是北京市科委下达课题――新型空调蓄热装置的研制(课题编号:
H020520010120)的一部分,主要研究内容是以本课题组开发的新型相变蓄热材
料和填充了该相变材料的蓄热槽为研究对象,研究核心是:在满足蓄热量要求的
情况下,如何缩短相变材料的蓄、放热时间,提高蓄放热效率。影响相变材料蓄
热量和蓄放热时间的因素分为两大部分:相变材料与热媒体。热媒体的流量、材
料的几何形状和材料的物性是其中的重要影响因素。因此我们建立了蓄热槽的数
学模型,采用数值计算方法对其进行求解分析,搭建了相变材料的蓄放热实验台,
对该材料进行了反复的蓄放热实验,通过对蓄热槽的数值模拟计算以及对实验数
据的分析,初步掌握相变蓄热装置的几何特性、热媒体的流动特性以及相变材料
的物化特性对蓄放热过程的影响,为蓄热槽的设计、优化、评价提供参考依据。
具体研究方法和过程是:
1、分析了相变传热问题的特点、建立了相变传热问题的数学模型、对相变
传热问题的求解方法进行了分析和比较,详述了采用数值方法求解相变传热问题
的步骤;
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北京工业大学工学硕士学位论文
2、引入二维板状模型,对二维模型进行合理简化,建立二维模型的控制方
程。采用显热容法、利用数值手段对控制方程进行求解。分析和研究了影响相变
材料蓄放热特性的因素,通过数值模拟计算的方法,找到这些影响因素的影响规
律以及它们之间的内在关系。
3、根据相变蓄热装置蓄放热特性的实验要求,设计并搭建了蓄放热实验台;
设计了多组蓄放热实验方案并进行了实验,对实验结果进行了分析,并把实验台
的实验结果与数值模拟结果进行比较,分析了偏差的原因并验证了理论模型的适
用性。
通过对二维板状模型的数值模拟计算研究以及填充了新型板状相变材料的
蓄热装置的蓄放热特性实验结果的分析,初步掌握了板状相变材料的高度、厚度、
导热系数、流体流速、换热系数对相变蓄热装置蓄放热特性的影响规律,对所研
制的相变蓄热装置首次提出了优化设计的方案,为相变蓄热装置的设计、优化、
评价提供了参考依据。
ABSTRACT
Energy is the base of pushing the society progress and survive of humankind. In
the latest 100 years, world energy wastage increased averagely 3﹪ every year, at the
same time the depletion of large quantity energy brought the very serious environment
problems, for example the weather changing warm, environment destroyed, air
pollution etc. All these restrict badly the development of mankind society and
economic activities. In our country energy and environment condition is also such.
Developing the new kinds of energy, increasing the energy utilization efficiency,
making use of the technique of saving energy have become the world urgent demand.
With the rapid development of economy and the improvement of standard of living,
people bring forward the higher request of the environment of work and living, and
the energy consumed about heating, ventilation and air conditioning increases rapidly,
so the burthen difference of the peak and vale is further aggrandized. Making use of
the thermal storage equipment to balance the thermal energy supply on time and the
strength is an economic and viable way. The thermal storage equipment can use the
low valley period of electricity and translate the cheap electric power to the thermal
energy and store the thermal energy. At the high peak period of energy, the thermal
energy stored is released out to reduce the quantity of electricity, and realize“ cut
peak and fill vale”.These not only save consumedly the running cost of the air
condition, but also alleviate the burden of electric power;And it makes the allotment
of time more reasonable about using electricity. Therefore researching the thermal
storage equipment used in the air conditioning system has important realistic meaning
and vast foreground.
This study is a part of the subject from Beijing Science Institution. The subject is
studying and manufacturing a new kind of air-conditional thermal storage equipment
(subject number: H020520010120). Our subject group develops a new kind of phase
change material. The study object is the PCM and the heat-storing bed filled with the
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北京工业大学工学硕士学位论文
PCM. The study core is: at the request of satisfying the heat-storing quantity, how to
shorten the heat charge and discharge time of PCM and increase the heat charge and
discharge efficiency. The influence factors of the heat-storing quantity and the heat
charge and discharge time are divided into two parts: PCM and hot medium. The flux
of the hot medium, the figure of PCM, the physical parameters of PCM, thermal
conductivity and heat-transfer coefficient are the important influence factors.
Therefore we establish the mathematics model of heat-storing bed and adopt the
numerical method to solve and analysis it and set up the experiment equipment of
thermal storage and discharge and do experiment again and again. By the calculation
using the numerical method and analyzing experiment data, we master the influence
of geometric characteristics of phase change thermal storage equipment and flow
characteristics of fluid media and physical and chemic characteristics of phase change
material in thermal storage and discharge process .So we provide reference base for
designing, optimizing and evaluating the phase change thermal storage equipment.
The study method and process is as follows:
1、Analyzing the characteristics of the phase change problem, establishing the
mathematics model of the phase change problem, comparing and analyzing the
methods used to solve the phase change problem, introducing in detail the process of
solve the phase change problem by using numerical method;
2、Introducing the two-dimensional model, proceeding reasonable simplification,
establishing the control equations of the two-dimensional model. Adopting specific
heat method and making use of numerical method to solve the control equations,
proceeding numerical calculation about the influence factors, analyzing these factors
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