热管式太阳能集热对喷射制冷系统性能影响的研究

发布时间：2019-06-02 00:39

【摘要】：随着环境污染和能源危机的加剧,清洁能源的利用受到了越来越多的关注,太阳能与住宅建筑的结合成为学者研究的重点,其中以太阳能为驱动能源的太阳能喷射制冷系统具有结构简单、运行稳定、可以利用低品位热源等优点,其研究开发具有重要的意义。然而,太阳能喷射制冷系统对太阳辐射强度具有较强的依赖性,太阳能辐射强度的周期波动性势必引起集热系统集热特性的变化,进而影响喷射制冷系统的性能。为了进一步提高太阳能的利用率,本课题采用热力计算和实验研究的方法进行了太阳能热源与喷射制冷系统性能的耦合关联研究,主要工作如下:首先,基于热力学基础,推导出太阳能喷射制冷系统各部件（火用）损失的计算公式,通过对不同太阳辐射强度下,太阳能喷射制冷系统中各部件的（火用）损失进行分析,结果表明:在整个系统中,集热器的（火用）损失所占的比重最大,占系统总（火用）损的74%~79%,喷射器（火用）损占系统（火用）损的比例仅次于集热器,占系统总（火用）损的10%左右,发生器（火用）损占系统总（火用）损的比例呈逐渐增大的趋势,从3.24%增加到10.96%,蒸发器、冷凝器、工质泵这三个部件的（火用）损失占总（火用）损的比例均为1.5%左右,节流阀的（火用）损所占的比例最小,占整个系统（火用）损的0.4%左右。其次,搭建了太阳能集热测试实验台,对集热水箱水量、循环流量等参数对系统性能的影响进行了分析,结果表明:当水箱水量为200L、400L、600L时,循环流量分别为10L/min、13L/min、15L/min时,水箱一天的水温增幅最大;水箱温度在一天的变化趋势大致相同,呈逐渐上升趋势,水箱水量为200L时水温上升幅度最大,最高温度可达85℃左右,600L时水温上升幅度最小;系统瞬时效率随着时刻的推移在某一区间上下波动,其波动的幅度与太阳辐射值的波动幅度相同,随着循环流量的增加,系统瞬时效率均呈增加的趋势。水箱水量为200L、400L、600L,循环流量分别为8L/min、13L/min、15L/min时,系统的平均瞬时效率达到最大值,最大平均瞬时效率分别为60.1%、63.5%、74%;最后,结合上述实验研究和课题组前期建立的喷射制冷系统热力学计算程序,对不同集热参数下太阳能喷射制冷系统的COP和制冷量的变化进行分析,结果表明:在水箱水量为200L时,循环流量为10L/min时,系统COP达到最大值,最大值为0.37;水箱水量为400L时,循环流量为13L/min时,系统制冷量达到最大值,最大值为22MJ。
[Abstract]:With the aggravation of environmental pollution and energy crisis, more and more attention has been paid to the utilization of clean energy. The combination of solar energy and residential buildings has become the focus of scholars' research. The solar jet refrigeration system driven by solar energy has the advantages of simple structure, stable operation and low grade heat source, so its research and development is of great significance. However, the solar jet refrigeration system has a strong dependence on the solar radiation intensity, and the periodic fluctuation of the solar radiation intensity is bound to cause the change of the heat collection characteristics of the heat collection system, and then affect the performance of the jet refrigeration system. In order to further improve the utilization rate of solar energy, the coupling relationship between solar heat source and the performance of jet refrigeration system is studied by means of thermodynamic calculation and experimental research. The main work is as follows: first, based on thermodynamic basis, The calculation formula of exergy loss of each component of solar jet refrigeration system is derived. The exergy loss of each component of solar jet refrigeration system under different solar radiation intensity is analyzed. The results show that in the whole system, The exergy loss of the collector accounts for the largest proportion, accounting for 74% of the total exergy loss of the system, and the proportion of the exergy loss of the ejector (exergy) is second only to that of the collector, accounting for about 10% of the total exergy loss of the system. The proportion of generator (exergy) loss to the total exergy loss of the system is gradually increasing, from 3.24% to 10.96%, evaporator, condenser, The exergy loss of these three components of the working fluid pump accounts for about 1.5% of the total exergy loss, and the exergy loss of the throttle valve accounts for the smallest, accounting for about 0.4% of the exergy loss of the whole system. Secondly, a solar heat collecting test platform is set up, and the effects of water quantity and circulating flow rate of the heat collecting tank on the performance of the system are analyzed. the results show that when the water quantity of the tank is 200L, 400L and 600L, the circulating flow rate is 10L 鈮，

本文编号：2490696