空气源热泵热水器的优化策略及性能分析

空气源热泵热水器具有运行工况广、冷凝温度时变的特点,机组在运行至较高水温时系统效率会有明显下降。针对这一问题通过实验比较不同外部工况下系统性能的变化规律,分析热泵热水器的实际运行特性和制热性能劣化的原因,并依此提出以控制电子膨胀阀开度和压缩机启停时机的优化策略来提升系统性能。实验结果表明,系统性能分别提升了24.8%和14.3%。同时分析了两种策略的优势与差异性,以期使空气源热泵热水器在实际应用中的制热效率得到最大程度地优化。     

直流变频空气源热泵热水器的实验研究

针对普通定频空气源热泵热水器不能在宽负荷和宽温度条件下运行等缺陷,提出一种直流变频空气源热泵热水器。通过对样机进行实验,得出了制热量、功率、COP值、吸气温度、排气温度等性能参数随压缩机运行频率的变化规律。结果表明直流变频热泵热水器能在宽负荷、宽温度条件下稳定运行。     

寒冷地区用空气源热泵热水器准双级压缩循环特性研究

空气源热泵热水器在寒冷地区运行时会出现排气温度过高、制热性能弱等弊端,准双级压缩循环技术可有效改善其在寒冷地区的运行特性。采用带中压补气的转子压缩机,研制了以R410A为循环工质的空气源热泵热水器,试验研究了系统在寒冷地区低温环境下的制热性能。结果表明:带中压补气的空气源热泵热水器系统排气温度较无补气有所降低,当室外温度从7.0下降到-25.0℃时,与无补气系统相比,补气系统制热量提升了6.2%～15.5%,压缩机功率提升了2.8%～9.5%,COP_h提升了3.3%～9.6%。     

大型热回收型空气源热泵机组冬季运行特性及其试验分析

介绍了热回收型空气源热泵机组的系统原理，分析了大型热回收型空气源热泵机组冬季运行特性，提出了机组相应的运行模式，并对机组在冬季工况下的运行性能进行了试验研究，分析了机组在该运行工况下需要考虑的问题，并提出了相应的解决方法。     

空气源热泵热水器系统的模拟计算

空气源热泵热水器已经成为一种新兴的热水器形式，从压缩机、冷凝器、节流阀和蒸发器四大部件出发，建立了各自的数学模型，尤其对冷凝器和蒸发器，建立了精确度相对较高的稳态分布参数分段模型。并对系统稳态运行性能进行了模拟分析。主要探讨空气进口参数、冷却水进口参数和流量对系统的影响。结果表明。当冷却水进水温度为20℃，回水温度为50．5℃时，冷却水流量可达到1．8kg／min。系统制热系数可达4．2。可见，空气源热泵热水器是一种比较有前景的节能技术。     

节能产品惠民工程:高效节能空气源热泵热水器(机)推广实施细则

一推广产品范围及要求(一)推广产品为电动机驱动,采用蒸气压缩制冷循环,以空气为热源,以提供热水为目的的热水器(机)。低温型空气源热泵热水器(机)不纳入推广范围。(二)申请推广的产品必须满足以下要求:1. 静态加热式空气源热泵热水器(机)性能系数COP 达到 3.4W/W 及以上;一次加热式和循环加热式空气源热泵热水器(机)性能系数COP达到3.7W/W及以上;2. 通过国家认可的第三方机构能效检测;     

空气源热泵热水器系统优化计算及实验研究

对现有的空气源热泵热水器系统部件提出了优化目标与方向,并进行相应计算和实验验证。通过分别对热泵工质充注量、冷凝盘管长度以及系统匹配问题的研究,结合实验结果证明了经过优化后,热泵热水器系统的性能COP显著提高,并且稳定性得到改善。     

套管壁厚度对直热式空气源热泵热水器性能的影响

文章对不同套管内管壁厚度的直热式空气源热泵热水器的性能进行试验研究,分析了不同套管内管壁厚度对套管换热器的传热面积、水流速度、传热系数、水系统阻力和热泵热水器的制热量、能效比等的影响。对5台不同套管直热式空气源热泵热水器进行试验的结果表明,设计适当的套管内管壁厚度,不仅提高了热泵热水器的能效比,而且增大了制热量,降低耗电量。当套管内管壁厚度为0.7 mm时,热泵热水器的能效比最大。     

空气源热泵热水器的性能分析

为了预测空气源热泵热水器性能,在焓差实验室内采用控制水流量的方法,通过改变环境温度和出水温度研究空气源热泵热水器的性能参数的变化,结果表明吸排气压力随着环境温度的升高而升高,制热量和COP随着环境温度的升高而升高;机组在环境温度较低的情况下运行时压缩机的压比大,导致排气压力、排气温度过高,制冷量较低,效率低,不能达到所需的水温;环境温度与排气温度相差过大,热损失较为严重;空气侧换热器容易结霜造成换热热阻增大,风量减小,使机组的换热效率越来越低。     

空气源热泵制冷热回收机组技术可行性分析

本文对一台普通的空气源热泵进行热回收改造,利用回收的热量加热生活热水.改造后的机组在实验台上进行了全年运行工况测试,通过对机组改装前后的运行工况的分析对比,提出了带热回收装置的空气源热泵是一种节能的空调与热水机组,并对机组在冬季的运行过程中可能出现的问题作了说明.     

进水温度对汽液两相流激波升压特性影响的实验研究

采用实验方法研究了进水温度对汽液两相流激波升压特性的影响。实验采用供热机组的工业抽汽；由蒸汽喷嘴，混合腔及相应的阀门和管道组成汽液两相流激波升压装置，实验发现存在一个临界进水温度，当水温度大于该临界值后，汽液两相流激波升压装置的升压特性将严重下降。     

An empirical model for predicting the length of a capillary tube

Any refrigerant device consists of several parts, and one of the most significant parts is the expansion device. This expansion device can be classified into several types according to the size of the refrigeration system. The capillary tube is used usually with a small refrigerant system size to reduce the higher pressure in the condenser into the low pressure in the evaporator. In this study, the effect of the capillary tube's diameter and that of the temperature of the condenser and evaporator on the length of such a device has been theoretically studied. Furthermore, a validation between the theoretical analysis and experimental findings from the literature review has been carried out. To achieve the theoretical aspect, MATLAB code has been developed. The results showed that the maximum difference between the theoretical and experimental results regarding temperature and pressure refrigeration is around 5% and 3.4%, respectively. Also, the results depict that the inner diameter and the condenser temperature have an effect on the length of the capillary tube. However, the effect of the inner diameter is higher compared with the condenser temperature. In addition, an equation to predict the length of the capillary tube has been developed with an accuracy of 98%. This equation is created as a function of the capillary tube's diameter and the temperature of the condenser and the evaporator. Moreover, this equation can be used to predict the length of the capillary tube for small refrigeration devices, especially those operating under 10 KW. The findings of this study can help make a mathematical approach used for the design of the capillary tube simpler and easier to apply.     

Thermal droplet size measurements using a thermocouple

During the investigation on atomization and evaporation of water in steam spray coolers a thermal measuring device has been developed for droplet size measurement. This device consists of a thermocouple on which the droplet evaporates by heat removal from the thermocouple material near the hot junction; it is called: droplet detecting thermocouple (d.d.t.). The principle of a d.d.t. is based on utilization of the correlation between droplet radius and temperature signal of the d.d.t., caused by the evaporating droplet. The d.d.t. proved to be a dependable device for continuous detecting and measurement of water droplets both in air and steam flows, even at high pressures and temperatures. In this paper a theoretical analysis of the d.d.t. behaviour is given together with experimental data of d.d.ts. for water droplets with radii between 3 and 1188 μm. Good agreement between experimental data and theoretically predicted results has been reached.     

Experimental investigation of high temperature congregating energy solar stove with sun light funnel

A solar stove which uses a light funnel to guide light and congregate solar energy has been designed. Its structure and operation principle have been introduced. The performance tests under the real weather have been carried out and the graphic lines of experiment have been given. The experimental result shows that the maximum temperature inside the stove is as high as 250 °C under the condition of 1.5 m² of lighting area, 70% reflectivity of reflecting aluminum foil inside surface of concentrator and no load (without water inside the coil pipe). When reflectivity is 86% the heat collecting efficiency of the device is about 43%. The collecting power that the stove receives can be up to 500 W. It is an ideal medium and high temperature solar energy congregating device suitable for industrial usage or cooking and other domestic usage.     

磁悬浮液体密度计及其标定

改进了一种利用磁悬浮和霍耳效应的液体密度计及其标定方法，描述了该密度计的结构，给出了分段拟合二变量实验曲线的标定方法。这种密度计适用于在太阳池中连续地测量不同深度处盐水的浓度和密度。计算表明，在太阳池中可能出现的温度和盐浓度的范围内，标定结果与实验数据精确相符。     

An axial heat transfer analytical model for capillary-pumped loop vapor line temperature distributions

This paper aims to study the capillary-pumped loop (CPL) vapor line temperature distributions. A simple axial heat transfer method is developed to predict the vapor line temperature from evaporator outlet to condenser inlet. CPL is a high efficiency two-phase heat transfer device. Since it does not need any other mechanical force such as pump, furthermore, it might be used to do the thermal management of high power electronic component such as spacecraft, notebook and computer servers. It is a cyclic circulation pumped by capillary force, and this force is generated from the fine porous structure in evaporator. A novel semi-arc porous evaporator to CPL in 1U server is designed on the ground with a horizontal position and scale down the whole device to the miniature size. From the experimental results, the CPL could remove heat 90 W in steady-state and keep the heat source temperature about 70 °C. Finally, a good agreement between the simulation and experimental values has been achieved. Comparing with experiment and simulation results, the deviation values of the distributions of the condenser inlet temperature are less than 8%.     

移动颗粒层过滤高温除尘器中循环清灰系统的试验研究

介绍能连续稳定高效运行的颗粒介质气力循环清灰系统,包括颗粒介质供在,传输系统和清灰器结构优化试验研究,系统的运行规律证明连续稳定循环清灰可行,对移动颗粒层过滤高温除尘技术开发有较大参考价值。     

Convective heat transport along a thermoacoustic couple in the transient regime

This work proposes a simple calculus procedure based on the linear thermoacoustic theory. The methodology applies on rate of change (time derivative) rather than on steady state temperature distributions so it constitutes a complementary to conventional analysis to perform test on the reliability and applicability of the linear theory. The procedure has been applied to experimental data collected by means of a simple prototype of thermoacoustic device. The apparatus, whose technical characteristics are described in detail along with the data acquisition procedure, has been able to highlight the general features of the thermoacoustic effect. Measurements concern the acoustically generated temperature gradients across a ThermoAcoustic Couple, a structure firstly introduced by Wheatley and coworkers in 1983. The obtained results indicate that heat transfer phenomena are more critical than non linear acoustic behavior in determining the overestimation that theoretical predictions make on experimental values.     

Design optimization of thermoelectric devices for solar power generation

We present an improved theoretical model of a thermoelectric device which has been developed for geometrical optimization of the thermoelectric element legs and prediction of the performance of an optimum device in power generation mode. In contrast to the currently available methods, this model takes into account the effect of all the parameters contributing to the heat transfer process associated with the thermoelectric device.The model is used for a comparative evaluation of four thermoelectric modules. One of these is commercially available and the others are assumed to have an optimum geometry but with different design parameters (thermal and electrical contact layer properties).Results from the model are compared with experimental data of the commercial thermoelectric module in power generation mode with temperature gradient consistent with those achievable from a solar concentrator system. These show that it is important to have devices optimized specifically for generation, and to improve the contact layer of the thermoelements accordingly.     

基于可调谐半导体激光吸收光谱技术的甲烷气体监测研究

设计了一种基于可调谐半导体激光吸收光谱技术的甲烷(CH4)气体监测装置,该装置具有温度监测范围大、监测精度高和实时监测的优点。监测装置的激光光源为波长1650 nm的反馈式激光器,应用波长调谐与锁相放大器技术,对周围环境进行温度补偿与背景扣除,可以较准确地测量周围环境中CH4的体积分数。实验表明,当CH4体积分数小于1%时,该装置的监测精度为±0.02%;当CH4体积分数大于1%时,装置监测误差小于±0.8%,实时监测的最长响应时间为10 s。装置的温度范围为0~40℃,可满足大多数工业生产中对CH4等气体体积分数的监测需求。