室外翅片管换热器的设计对空气源燃气机热泵系统性能的影响

研究了翅片管换热器的流路布置和支路数对空气源燃气机热泵系统性能的影响,研究结果表明:采用逆交叉流的流程布置方式空气源燃气机热泵的性能最好,而采用顺流的流程布置方式最差,与顺流相比,采用逆交叉流的流程布置方式空气源燃气机热泵性能提高了10%左右.翅片管换热器支路数采用14路比采用7路时空气源燃气机热泵性能提高了7%左右.因此,翅片管换热器的设计对空气源燃气机热泵系统性能有较大的影响,合理设计翅片管换热器对提高空气源燃气机热泵的性能起到了一定的作用.     

竖埋螺旋管地热换热器理论模型及实验研究

对竖埋螺旋埋管地热换热器建立了传热模型，分析了流量、土壤传热系数对热输出的影响，并计算了等效传热系数、竖埋螺旋埋管换热器对土壤温度场的影响情况。在理论计算的基础上，对一竖埋螺旋管地源热泵系统进行了实验研究，对比分析了理论计算值和实验测试值，并分析了热泵系统的性能。     

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。     

间歇式热处理炉传热计算与分析

建立了台车式热处理炉炉膛传热数学模型和辐射换热器工作模型,分析了换热器的传热特性（空气预热温度、壁温、传热系数）随炉况的变化。结果表明,辐射换热器的传热特性随炉子的升温及保温过程变化而波动很大,因而对炉子的热工性能产生了影响。     

双级耦合热泵在北方高层建筑中应用的初探

依据北方高层建筑供热的特点,设计了一种生态循环供暖系统——以空气为低位热源的双级耦合热泵系统,给出了几种可供选择的具体方案及其对应的末端装置,并对高层建筑中空气源热泵室外换热器的安装问题进行了探讨,提出了可行的方案。最后文章还给出了两种提高系统供热季节性能系数的方法。     

热混联板式换热器传热系数计算方法研究

利用板式换热器热工性能测试平台对E100-M深波纹人字形板式换热器进行测试并对试验数据进行分析,发现在热混联板式换热器中,不同混装方式下影响传热系数的关键因素是混合通道所占的比例。对热混联组装方式在全小角至全混角、全混角至全大角的试验数据进行线性拟合,得到相应的传热系数计算公式。通过类比分析得到板式换热器热混联传热系数的通用计算公式,并与试验数据进行比较,发现其计算误差在10%以内。     

太阳能辅助热泵空调机组室外侧换热器研究分析

以太阳能辅助热泵空调机组为例,对辅助换热器系统、切换式双热源系统和复合换热器系统进行了对比分析,从研究背景、系统设计、换热器设计、运行模式等方面,阐述了室外侧换热器的开发及应用。     

余热复合式燃气机空调数值计算及性能研究

建立了燃气机热泵空调系统模型,包括燃气发动机、压缩机、换热器、空调系统和建筑负荷模型。通过对模型的求解及结果分析,得到了燃气机热泵空调的性能。结果显示夏季燃气机热泵系统的二次换热器能够替代常规电力空调的电再热器实现空调风再热。冬季二次换热器能够实现系统余热直接向室内供暖,室外温度不太低时可以充分利用发动机余热实现房间供暖。室外温度较低时,可以实现发动机余热和热泵系统联合供暖,节能效果明显。在夏季系统的最大一次能源利用率能达到1.6以上,冬季最高能达到1.8以上。系统具有良好的能源利用效率。     

热阻和内不可逆性对空气热泵循环性能的影响

研究热阻对空气热泵循环性能的影响，用有限时间热力学方法导出计入高，低温侧换热器热阻损失和压缩机，膨胀机不可逆损失的空气热泵循环供热率与供热系数解析公式，由此可得对应于最大供热系数的最佳压比和供热率，供热系数关系。计算表明，存在一个最大供热系数值，供热系数与供热率呈类似抛物线关系，不同于内可逆条件下的单调递减关系。     

板式换热器再生水污垢影响换热实验台的搭建和初步实验研究

经城镇污水处理厂处理后的二级再生水进入板式换热器会引起结垢,从而影响板式换热器的流动换热性能.针对这一问题搭建了现场实验台,在可调节工况下实时监测板换传热系数及流动压降,目的是研究板换再生水侧污垢的时变规律,并特别关注板换性能从初始清洁状态到预定清洗点之间的变化过程.研究为再生水源热泵系统及其板式换热器的设计与运行提供了重要参考依据.     

A study of the influence of solar radiation on the thermal performance of evaporators of heat pump systems

Solar radiation has remarkable influence on the thermal performance of evaporators of heat pump systems. This paper proposes a method for considering the influence with correcting the heat transfer coefficient of evaporators. A test setup of a heat pump system was built, and long-term experimental data were obtained. The heat transfer coefficient with solar radiation is 36.2% greater than that without it in the experimental conditions. The correction method presented can be used not only to improve analysis and simulation of the thermal performance and energy consumption of heat pump systems, but also to assist in the design and installation of evaporators and the heat pump systems.     

空气-沙子移动床换热器传热特性实验研究

面向太阳能热发电系统,建立一种空气-沙子移动床换热器实验平台,对其在不同参数下进行传热性能的实验研究.并基于实验数据,利用线性回归拟合得到表观气固传热系数的关联式,其整个实验工况预测值与实验值的平均误差为3.57％.研究结果表明:较高雷诺数可提升空气-沙子移动床换热器的传热效能,空气进口温度为281℃时,空气-沙子移动...     

An experimental investigation on frosting characteristics of a microchannel outdoor heat exchanger in an air conditioning heat pump system for electric vehicles

To increase the driving range of electric vehicles in cold climate, air conditioning heat pump (ACHP) system is supposed to be the most effective solution. Working near 0°C with high humidity, the microchannel outdoor heat exchanger (OHX) in system would experience badly frosting process, like traditional residential heat pump system. It would lead to a significant reduction of system performance without defrosting in time. In this article, experimental investigation has been implemented on the frosting process of ACHP system of electric vehicles which is with a microchannel OHX. The phenomenon of frosting distribution was observed, the frosted part on surface shows uneven with various flows paths. The typical frosting characteristics of an outdoor microchannel heat exchanger were also obtained. In a self-designed three-heat exchanger ACHP system, the inlet and outlet refrigerant temperature of OHX as well as the outlet air temperature of system decrease with increasing frosting coverage rate. The frosting phenomenon was analyzed with variation of ambient temperature and humidity. System influence by frosting was also studied with under different ambient conditions. When OHX begins to frost, the heating capacity reduction of system under different ambient conditions were both increased but the differences in the coefficient of performance (COP) variations under different ambient conditions were small as frosting progressed.     

Preliminary investigation of a transcritical CO2 heat pump driven by a solar‐powered CO2 Rankine cycle

In this paper, a transcritical carbon dioxide heat pump system driven by solar‐owered CO₂ Rankine cycle is proposed for simultaneous heating and cooling applications. Based on the first and second laws of thermodynamics, a theoretical analysis on the performance characteristic is carried out for this solar‐powered heat pump cycle using CO₂ as working fluid. Further, the effects of the governing parameters on the performance such as coefficient of performance (COP) and the system exergy destruction rate are investigated numerically. With the simulation results, it is found that, the cooling COP for the transcritical CO₂ heat pump syatem is somewhat above 0.3 and the heating COP is above 0.9. It is also concluded that, the performance of the combined transcritical CO₂ heat pump system can be significantly improved based on the optimized governing parameters, such as solar radiation, solar collector efficient area, the heat transfer area and the inlet water temperature of heat exchange components, and the CO₂ flow rate of two sub‐cycles. Where, the cooling capacity, heating capacity, and exergy destruction rate are found to increase with solar radiation, but the COPs of combined system are decreased with it. Furthermore, in terms of improvement in COPs and reduction in system exergy destruction at the same time, it is more effective to employ a large heat transfer area of heat exchange components in the combined heat pump system. Copyright © 2012 John Wiley & Sons, Ltd.     

海水源热泵抛管式换热器管外传热特性研究

为给海水源热泵抛管式换热器的优化设计提供理论依据,通过计算流体力学(CFD)数值软件对该系统中的流动和传热过程进行数值模拟。结果表明,管内对流换热努谢尔特数Nui随抛管曲率比δ、无因次节距H_o的增大而减小;管外Nu_o随δ、H_o的增大而减小,而且δ和H_o对Nu_o的影响是复杂非线性关系。在一定模拟工况下,管外表面传热系数比管内小,热阻比管内大,换热器传热性能的决定性因素在管外,基于此,该文通过数值模拟拟合出适于南海岛礁海水源热泵抛管式换热器管外传热准则关联式。     

空气源热泵系统无霜化方法概述

从提高空气温度和改变空气湿度两方面详细阐述了空气源热泵系统无霜化处理方法,简单介绍了各方法的原理及相对除霜式空气源热泵所具有的优势。最后对空气源热泵无霜化的研究方向进行展望:可以利用余热或太阳能提高流经室外换热器空气的温度以实现无霜化;进一步研究固体除湿剂在低温环境下的吸附能力和再生能力;重点探究除湿溶液的再生方法以及再生能量来源和再生后水蒸气利用;加大研发更加高效的除湿溶液和防冻溶液。     

Heat-pipe enhanced solar-assisted heat pump water heater

A heat-pipe enhanced solar-assisted heat pump water heater (HPSAHP) is studied. HPSAHP is a heat pump with dual heat sources that combines the performance of conventional heat pump and solar heat pipe collector. HPSAHP operates in heat-pump mode when solar radiation is low and in heat-pipe mode without electricity consumption when solar radiation is high. HPSAHP can thus achieve high energy efficiency. A prototype was designed and built in the present study. An outdoor test for a HPSAHP in the present study has shown that COP of the hybrid-mode operation can reach 3.32, an increase of 28.7% as compared to the heat-pump mode COP (2.58).     

深层地埋管换热器换热性能模拟及稳定性研究

以深层地源热泵地埋管换热器为研究对象,对其换热特性进行数值模拟和实验研究。建立考虑轴向地温梯度的深层地埋管换热器传热模型并进行模拟计算,通过示范工程现场测试数据验证该模型的正确性。对深层地埋管换热器换热的性能稳定性进行研究,发现深层地埋管换热器连续长期运行及间歇长期运行下换热性能基本稳定。当按不同运停比运行时,岩土温度恢复效果良好。研究结果表明深层地源热泵有较好的换热性能及运行稳定性,为深层地热能的开发利用提供了新思路。     

Experimental study on the performance of air source heat pump system with multiple parallel outdoor units

This paper presents a novel air source heat pump for heating of buildings named air source heat pump with multiple parallel outdoor units (ASHPMO). Multiple outdoor units were connected in parallel with the aim of realising alternate defrosting and uninterrupted heating simultaneously. An experimental apparatus of the ASHPMO system was developed. The defrosting performance was experimentally investigated under different outdoor air temperatures, outdoor air relative humidity, and condensation temperatures, among other factors. The test results showed that the novel ASHPMO system could provide continuous heating when defrosting even under an outdoor air temperature of −10°C. Variations in compressor vapour suction and discharge pressure and temperature were observed. The minimum heating capacity could still reach 60% of that without defrosting. Under the defrosting condition with outdoor air temperature −10°C, both the heating coefficient of performance (heating COP) and total energy efficiency ratio (EER) of the system can reach to 2.0 and 2.32, respectively.     

四热源吸收式热泵的传热面积优化

建立一种不可逆的四温度位吸收式热泵模型，导出其最小传热面积与四热源熵变化率的关系并得到了热力学第二定律的类比表达式，获得了最佳供热率、性能系数和传热面积之间的优化关系，所得结论可为四热源吸收式热泵的优化设计和最佳工况选择提供新的理论途径。