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空气源热泵热水机组除霜方式的研究 总被引:1,自引:0,他引:1
本文阐述了结霜对空气源热泵热水机组性能的影响,分析了结霜影响机组性能的原因,指出现有除霜方法的利弊,提出了改进的机组除霜方法和运行方式。 相似文献
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对空气源热泵结霜特性进行了分析,讨论了空气源热泵换向除霜存在的问题,并提出了一种空气源热泵降湿除霜新系统,从根本上解决了冬季供热时的结霜问题,从而解决了因结霜而导致的运行可靠性和稳定性差的根本问题。 相似文献
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冷库冷风机"按需除霜",可有效降低冷库能耗、提高能源利用率。本文将湿空气物性参数、冷风机运行时间作为神经网络输入变量,建立基于BP算法训练的多层前馈神经网络结霜量与除霜时长预测模型,并利用相关试验数据进行模型训练与测试。结果表明:结霜量预测模型计算值与试验测量值平均误差为10.11%,除霜预测模型计算值与试验测量值的误差均小于5%。本文所建立的基于人工神经网络结霜量预测模型与除霜时长预测模型可较好地预测冷风机结霜量与除霜时长,为实际工程应用中通过确定除霜起始点和除霜时长实现冷风机"按需除霜"提供了参考价值。 相似文献
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对试验使用条缝翅片换热器及R410A工质的空气源热泵空调器的除霜特性进行了试验研究,测量了除霜过程中热泵样机的制热量、输入功率、室外换热器进出口温度及压力等参数的动态变化,分析了不同工况下热泵样机的除霜损失.试验结果表明:随着室外环境温度和相对湿度的降低,热泵机组在除霜过程中消耗的能量及从空调房间中吸收的热量增大,尤其在环境温度低于0℃时,除霜过程中的损失增大更快.由于随着环境相对湿度的增大霜层增长速度加快,除霜过程中的损失占结霜/除霜循环总耗能及总制热量的比例增加,因此热泵机组结霜/除霜循环的平均制热量及COP迅速减小.与使用平翅片换热器的热泵机组除霜性能的比较表明,随环境相对湿度的增加,条缝片换热器热泵机组的结霜/除霜循环平均性能衰减速度要快的多. 相似文献
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现有无霜冰箱中多采用机械定时器定时除霜,为了解决此种方式除霜误判率高和能耗大等缺点,利用光在霜内发生的散射、反射、折射等作用的光学特性,设计了可以测量霜厚的红外式冰箱结霜传感器.该传感器以红外收发对管为核心,其机械结构可使其安装在冰箱蒸发器表面.设计了传感器的信号处理电路和单片机程序.传感器和冰箱的压缩机和除霜设备协同工作组成自动除霜系统,使冰箱工作在无霜状态.在结霜试验平台下进行的单件和多件一致性实验表明该传感器在0~5 mm内测量霜厚相对误差小于20%,绝对误差小于1 mm,满足冰箱探霜的要求.结冰实验表明结霜探测不受结冰的干扰. 相似文献
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结霜工况下风冷热泵翅片管蒸发器传热特性分析 总被引:1,自引:0,他引:1
在对饱和空气焓作了线性处理的基础上,推导出风冷热泵蒸发器结霜工况翅片温度分布、传热量及翅片效率的公式,通过实例分析了蒸发器的传热特性。 相似文献
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《Measurement》2016
With the development of human modern society at the turn of the new century, more and more people tend to use new technologies. To keep in tandem with modern technologies, food storage became easier with domestic refrigerators. In such systems, frost formation can be a fundamental problem especially in tropical countries with hot and humid ambient conditions. An adaptive method for defrosting the evaporator of a domestic refrigerator system is presented in this paper. In this method, parameters namely open door time, compressor ON time, previous defrost duration, mode of compressor, fans, and heater action before, during, and after defrost have been considered effective on defrost operation. Experiments have been carried out on two different case study top mounted freezers. Experimental results for case study 1 showed that the adaptive defrost in comparison to the fixed defrost cycles could reduce the energy consumption and Total Equivalent Warming Impact (TEWI) about 13% and 12.5%, respectively. The same parameters for case study 2 were decreased 5.5% and 5.2%, respectively. Furthermore, temperature variation of the compartments for both case studies decreased in comparison to that of their corresponding base case, which prevents quality loss of the stored food during defrost. Briefly, the results showed lower energy consumption, more environmentally friendly effects, and lower compartment temperature change. 相似文献
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转轮吸附除湿供冷空调系统是目前关注的一种新的空调形式,转轮除湿机是此类空调系统的关键部件,因此了解各种因素对转轮除湿机性能的影响是必要的。分析了转轮除湿机本体参数及空气参数等影响除湿供冷空调系统性能的因素,提出了被除湿后的处理空气露点控制优先的观点,可以为正确配置转轮除湿供冷空调系统提供理论指导。 相似文献
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一些特定的行业和场合对空气湿度有着一定的要求。在分析除湿原理的基础上,研究设计了小型固定床吸附式除湿机。介绍了其工作原理,并开发了基于AT89C51单片机及其它附加电路组成的控制系统,利用该系统实现了对湿度的自动控制。该系统已在对湿度要求较高的场所投入使用,使用结果表明其性能稳定可靠。 相似文献
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为了控制冷藏车厢内的温度波动,运用频域分析法对造成冷藏车厢内温度波动的4种温度扰动等因素进行了研究。研究结果表明:在保持车厢体积、当量换热面积、传热系数不变,减小系统交接频率,可对各温度扰动进行衰减;保持αF与ρсν的比值不变,可调整制冷机组运行频率及融霜频率处于系统衰减域,或使得制冷与融霜温度扰动的相角相同,达到对这两种扰动进行衰减的目的;减小车厢内外表面的对流换热系数、减少当量换热面积、减小车辆当量渗风孔面积越小、使车厢外表面颜色变浅、增大车速的变化频率等可达到降低车厢内温度波动的效果。 相似文献
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海上风力发电作为一种可再生的绿色能源,应用越来越广泛,并且有着广阔的发展空间.与其他发电方式相比,海上环境具有一定特殊性,风机设备长期处于高盐、高湿环境中,设备易于腐蚀,必须装配除湿机控制风机环境湿度.由于海况等环境因素维保人员只能在适合海上作业的窗口期进行设备巡检,一旦除湿机出现故障无法保障第一时间发现处理,导致设备... 相似文献
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Nun-Ming Liu Ko-Ta Chiang Chen-Ming Hung 《The International Journal of Advanced Manufacturing Technology》2013,67(5-8):1053-1066
This study provides the mathematical models for modeling and analyzing the effects of air-cooling on the machinability of Ti–6Al–4V titanium alloy in the hard turning process. A cold air gun coolant system was used in the experiments and produced a jet of compressed cold air for cooling the cutting process. The air-cooling process seems to be a good environment friendly option for the hard turning. In this experimental investigation, the cutting speed, feed rate and cutting depth were chosen as the numerical factor; the cooling method was regarded as the categorical factor. An experimental plan of a four-factor (three numerical plus one categorical) D-optimal design based on the response surface methodology (RSM) was employed to carry out the experimental study. The mathematical models based on the RSM were proposed for modeling and analyzing the cutting temperature and surface roughness in the hard turning process under the dry cutting process and air-cooling process. Tool wear and chip formation during the cutting process were also studied. The compressed cooling air in the gas form presents better penetration of the lubricant to the cutting zone than any conventional coolants in the cutting process do. Results show that the air-cooling significantly provides lower cutting temperature, reduces the tool wear, and produces the best machined surface. The machinability performance of hard turning Ti–6Al–4V titanium alloy on the application of air-cooling is better than the application of dry cutting process. This air-cooling cutting process easily produces the wrinkled and breaking chips. Consequently, the air-cooled cutting process offers the attractive alternative of the dry cutting in the hard turning process. 相似文献