串联式二氧化碳双级压缩制冷热泵系统分析

发布时间：2018-03-25 16:20

本文选题：全热回收　切入点：部分热回收　出处：《西安建筑科技大学》2014年硕士论文

【摘要】：随着人民生活水平的提高，日常生活中更多时候人们对冷和热有了同时的需求，为此，一系列具备制冷兼冷凝热回收功能的空调设备已被广泛推广使用，但绝大部分产品存在着冷热量相互制约、效率低下等问题。为了解决这些问题，本课题组提出了一种串联式二氧化碳双级压缩制冷热泵循环系统，该系统不仅能够同时制冷和制热，而且可以按用户的需要来调节制冷量和制热量，前期依据热力学第一定律对其所进行的研究表明：在某些工况下，该系统的性能甚至会高于制冷兼全热回收循环。本文是对该系统进行更深入研究，期望通过分析找出系统的薄弱环节，找到提高系统性能的途径和方向。依据分析方法的基本理论，本文首先建立了该系统各部件的分析模型；再利用建立的分析模型对该系统的全热回收工况、部分热回收工况、同时供冷供热工况进行了理论计算和分析；着重研究了高压压力、中间压力、冷冻水温度、冷却水温度、热水进出口温度、过冷度、过热度、流量系数等因素对系统效率的影响，找出了系统的薄弱环节。研究结果表明：对于全热回收工况，系统循环产生损失较大的部件是第二节流阀、高压压缩机和热水加热器。在部分热回收工况下，，热水入口温度决定了随着高压压力的增大，系统效率是否出现峰值；该工况下系统产生损失较大的部件是第二节流阀、室外侧换热器、高压压缩机和热水加热器。在同时供冷供热工况下，减小制冷量而增大制热量会使得系统效率随之下降；该工况下系统产生损失较大的部件是第一节流阀、高压压缩机、热水加热器。
[Abstract]:With the improvement of people's living standard, more and more people need both cold and heat in their daily life. Therefore, a series of air-conditioning equipments with the function of refrigeration and condensing heat recovery have been widely used. In order to solve these problems, our team proposed a series CO2 two-stage compression refrigeration heat pump circulatory system. The system can not only refrigerate and heat at the same time, but also adjust the refrigerating capacity and heating capacity according to the needs of the user. The previous study on the system according to the first law of thermodynamics shows that: under some conditions, The performance of the system is even higher than that of the refrigeration and total heat recovery cycle. This paper makes a further study of the system and expects to find out the weak links of the system and find out the way and direction to improve the system performance. According to the basic theory of the analysis method, this paper first establishes the analysis model of each part of the system, and then uses the established analysis model to analyze the whole heat recovery condition and part of the heat recovery condition of the system. At the same time, the working conditions of cooling and heating are calculated and analyzed theoretically, and the high pressure, intermediate pressure, freezing water temperature, cooling water temperature, inlet and outlet temperature of hot water, supercooling degree, superheat degree are studied emphatically. The influence of flow coefficient and other factors on the system efficiency is found out the weak link of the system. The results show that the second throttle valve, high pressure compressor and hot water heater are the main components of the system under the condition of total heat recovery, and under the partial heat recovery condition, the second throttle valve, the high pressure compressor and the hot water heater are the main components of the system. The inlet temperature of hot water determines whether there is a peak value of system efficiency with the increase of high pressure. High pressure compressors and hot water heaters. Under the condition of cooling and heating at the same time, reducing the refrigerating capacity and increasing the heating capacity will decrease the system efficiency. A hot water heater.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU83

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