分布式供热系统末端动力形式的研究

发布时间：2019-06-22 07:48

【摘要】：随着我国生活水平的不断提高以及建筑业的快速发展,集中供热系统的应用越来越广泛,但随之而来的是能源消耗的不断增长,使我国能源结构面临严峻的挑战。为解决传统供热系统中供热效果差、冷热不均、能源浪费等问题,分布式供热系统的提出得到了诸多专家学者的认可,与传统的供热系统相比,其具有水力稳定性高、适应热负荷变化能力强、输送效率高等优点,而且由于其末端动力形式的不同而形式多样,末端动力提供、热量按需分配是保证分布式供热系统安全可靠运行的关键技术。本文首先从结构和节能效果方面比较了分布式供热系统和传统供热系统两者的区别,分析了分布式供热系统的几种优点,然后提出了分布式供热系统的三种末端动力形式:变频泵、混水泵和喷射泵,表明末端动力形式是保证分布式供热系统运行的关键因素。其次对三种末端动力形式的工作原理、在系统中的应用及节能效果分别进行了详细分析:末端动力形式为变频水泵时,其利用改变电源频率大小的方式来改变电机转速,从而控制水流量大小的原理达到节约能源的效果,以济南市某供热管网为例,通过计算得出利用变频水泵作为末端动力形式与传统供热相比具有显著的节能效果;末端动力形式为混水泵时,本文以四通混水器为例,利用CFD软件模拟了其内部温度场的分布情况,其对二次网供水温度具有调节作用,并通过实例将混水泵与板换系统作比较得出混水泵作为末端动力形式能耗较小,具有节能效果;末端动力形式为喷射泵时,本文对喷射泵的结构设计进行了研究,也利用CFD软件对其内部温度场、速度场及压力场进行了模拟分析,并通过实例对比得出喷射泵作为末端动力形式既节约了能耗又减少了初投资,在供热系统中有极大优势。最后本文分别分析了三种末端动力形式的适用场所:变频水泵适用范围较广,特别适用于供热距离远、用户多、流量大的系统;混水泵适用于管网供水温度超过末端用户所需温度时的直连系统,如地面辐射采暖系统或同时存在散热器采暖及地暖采暖的系统,将混水泵安装在采用地暖系统的入口处;喷射泵适用于同时存在高、低区管网的系统,也适用于同时存在散热器采暖及地暖采暖的系统中,前提是要有足够的供回水压差。
[Abstract]:With the continuous improvement of living standards and the rapid development of construction industry in China, the application of central heating system is more and more extensive, but with the continuous growth of energy consumption, China's energy structure is facing severe challenges. In order to solve the problems of poor heating effect, uneven cooling and heat, energy waste and so on, the distributed heating system has been recognized by many experts and scholars. Compared with the traditional heating system, it has the advantages of high hydraulic stability, strong ability to adapt to the change of heat load, high transportation efficiency, and because of the different forms of power at the end of the system, the terminal power is provided. Heat distribution according to demand is the key technology to ensure the safe and reliable operation of distributed heating system. This paper first compares the difference between distributed heating system and traditional heating system from the aspects of structure and energy saving effect, analyzes several advantages of distributed heating system, and then puts forward three terminal dynamic forms of distributed heating system: variable frequency pump, mixed pump and jet pump, which shows that the terminal dynamic form is the key factor to ensure the operation of distributed heating system. Secondly, the working principle of three kinds of terminal power forms, the application in the system and the energy saving effect are analyzed in detail: when the terminal dynamic form is variable frequency pump, it can change the speed of motor by changing the frequency of power supply, so as to control the principle of water flow to achieve the effect of energy saving, taking a heating network in Jinan as an example. Through calculation, it is concluded that the use of frequency conversion pump as the terminal power form has a significant energy saving effect compared with the traditional heating. When the end dynamic form is the mixed water pump, this paper takes the four-way water mixer as an example, simulates the distribution of its internal temperature field by using CFD software, which can adjust the water supply temperature of the secondary network, and compares the mixed water pump with the plate exchange system. It is concluded that the energy consumption of the mixed water pump as the end power form is small and has the effect of energy saving. When the terminal dynamic form is the jet pump, the structural design of the jet pump is studied in this paper, and the internal temperature field, velocity field and pressure field are simulated and analyzed by using CFD software. Through the comparison of examples, it is concluded that the jet pump, as the terminal dynamic form, not only saves energy consumption but also reduces the initial investment, and has great advantages in the heating system. Finally, this paper analyzes three kinds of applicable places of terminal power form: variable frequency pump is widely applicable, especially suitable for the system with long heating distance, many users and large flow rate, and the mixed water pump is suitable for the direct connection system when the water supply temperature of pipe network exceeds the temperature required by the end user, such as the ground radiation heating system or the system with radiator heating and floor heating at the same time, and the mixed pump is installed at the entrance of the ground heating system, and the mixed water pump is suitable for the direct connection system when the water supply temperature of the pipe network exceeds the temperature required by the end user. The jet pump is suitable for the system with high and low area pipe network at the same time, and also suitable for the system with radiator heating and ground heating at the same time, provided that there should be enough water pressure difference.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU995

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