利用压缩机废热的空气源热泵蓄能除霜系统实验研究

发布时间：2018-06-06 15:31

  本文选题：空气源热泵 + 除霜　； 参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：空气源热泵在制热运行过程中，当室外环境温度较低、湿度较大时，室外机盘管壁面易发生结霜现象。霜层堆积严重影响机组的制热性能和效率。因此，需为在结霜区运行的热泵机组设计除霜方式，现使用最多的除霜方式是逆循环除霜。除霜模式下，四通换向阀换向，室外机作为冷凝器，室内机作为蒸发器。为了保证室内环境的舒适性，除霜时室内风机一般处于关闭的状态，这将导致除霜能量来源不足，除霜时间延长，除霜效率降低。 为了达到更好的除霜效果，本文构建了利用压缩机废热的空气源热泵蓄能除霜系统。基于理论分析，确定除霜能耗、相变蓄热器蓄热量，从而进行相变材料的预选和相变蓄热器的设计，并对所选相变材料的热稳定性进行研究。搭建常规除霜及蓄能除霜实验台，分析不同除霜模式下蓄能除霜系统的除霜能耗、动态特性以及除霜对室内环境的影响，并与常规除霜系统性能进行对比。 搭建相变材料热稳定性测试实验台，对摩尔比65%癸酸+35%月桂酸的相变材料进行4000次的循环测试，结果显示该二元复合有机相变材料具有较好的热稳定性。 分别对系统的常规除霜特性和利用压缩机废热的蓄能除霜特性展开实验研究，结果表明后者的除霜效果远优于前者。对比四种蓄能除霜模式可知，相变蓄热器充分蓄热、除霜过程中室内持续供热的除霜模式具有良好的除霜及室内供热效果，同时除霜能耗也最低。 确定系统的除霜控制策略。当系统达到除霜条件时，以相变蓄热器外圈下部的温度测点作为判断相变蓄热器是否充分蓄热的依据，当测点温度值低于相变材料终止相变温度22.0℃时，采用除霜过程中制冷剂不向室内供热的除霜模式，反之则采用除霜过程中制冷剂向室内供热的除霜模式。 本文的研究成果为相变蓄能技术的应用推广和空气源热泵在冬季供暖时运行效果的提高提供了一定的理论支持和技术储备，为降低建筑能耗起到一定的促进作用。
[Abstract]:During the heating operation of air source heat pump, frost is easy to occur on the wall of outdoor coil unit when the outdoor environment temperature is low and humidity is high. Frost accumulation seriously affects the heating performance and efficiency of the unit. Therefore, defrosting mode should be designed for heat pump units operating in frosting zone, and reverse cycle defrosting is the most commonly used defrosting mode. Defrosting mode, four-way reversing valve reversing, outdoor machine as condenser, indoor machine as evaporator. In order to ensure the comfort of indoor environment, the indoor fan is generally closed during defrosting, which will lead to insufficient defrosting energy sources, prolonged defrosting time and lower defrosting efficiency. In order to achieve better defrosting effect, In this paper, an air source heat pump defrosting system using compressor waste heat is constructed. Based on theoretical analysis, the energy consumption of defrosting and the heat storage of phase change accumulator are determined, so that the pre-selection of phase change material and the design of phase change accumulator are carried out, and the thermal stability of the selected phase change material is studied. The defrosting energy consumption, dynamic characteristics and defrosting effect on indoor environment of defrosting system under different defrosting modes were analyzed. Compared with the conventional defrosting system, the thermal stability of phase change material was tested by 4000 cycles, and the phase change material with 65% decanoic acid 35% lauric acid was tested for 4000 times. The results show that the binary composite organic phase change material has good thermal stability. The conventional defrosting characteristics of the system and the defrosting characteristics of energy storage using the waste heat of the compressor are studied experimentally. The results show that the defrosting effect of the latter is much better than that of the former. Compared with the four defrosting modes, the defrosting mode with phase change accumulator has good defrosting and indoor heating effect, and the defrosting energy consumption is the lowest. The defrosting control strategy of the system is determined. When the defrosting condition is reached, the temperature measuring points at the bottom of the outer ring of the phase change accumulator are taken as the basis for judging whether the phase change accumulator is sufficient for storing heat. When the temperature of the measuring point is lower than 22.0 鈩，

本文编号：1987173