补气增焓热泵机组运行性能模拟研究

基于空气源热泵机组在低温工况下的运行特性,对单级空气源热泵机组及补气增焓热泵机组进行仿真模拟计算,提出一种带补气的热泵机组运行性能的计算方法,得出不同蒸发温度下最佳补气压力值,对改善低温环境下空气源热泵机组的运行性能具有重要意义。     

R32空气源热泵机组性能试验研究

为了了解R32制冷剂应用于空气源热泵系统的性能,分别对采用补气增焓方案和喷液冷却方案的2台R32样机进行测试,并与同型号R22机组进行对比。试验结果表明,2台R32样机均能够安全稳定运行,在整机成本、系统简单性及可操作性方面,喷液冷却系统占有较大优势,但在低温适应性方面,补气增焓系统优势明显。最终根据性能试验结果,给出R32样机存在的问题及进一步优化设想。     

空气源热泵系统低温制热量改善途径实验分析

在室外宽范围温度环境运行情况下,通过对3HP空气源热泵机组采用变节流、增大换热器面积、压缩机补气增焓等三种手段进行低温制热量提升的详细的实验研究,指出三种不同的途径在改善空气源热泵系统低温制热量中的效果.实验结果表明,若把三种途径有机结合应用到空气源热泵系统中,可使一般的空调系统低温制热量有5%~15%的提升效果.     

两种低环境温度空气源热泵机组的对比试验研究

补气增焓与喷液冷却是低环境温度空气源热泵机组采用的2种主要的技术方案。本文分别采用这2种方案设计R410A低环境温度空气源热泵机组,并对二者的性能进行对比试验研究。结果表明:在制热名义工况下,2种机型的COP均在2.3以上,补气增焓型机组COP高于喷液冷却型机组约6%。变工况制热条件下,当环境温度高于7℃时,喷液冷却型机组制热量高于补气增焓型机组,在环境温度为21℃时,前者高出后者约8%;当环境温度在-10～7℃范围内时,二者制热量差异不明显;当环境温度低于-10℃时,补气增焓型机组制热量高于喷液冷却型机组。环境温度在-25～21℃范围内时,补气增焓型机组制热COP均高于喷液冷却型机组。     

中间补气的滚动转子式压缩系统的试验研究

将带中间补气的滚动转子式压缩机应用于空气源热泵系统,不仅可解决常规系统制热工况下制热量不足的问题,而且可改善制冷工况系统性能,进一步提升系统APF值。首先介绍中间补气的滚动转子式压缩系统(中间补气系统)的工作原理,然后利用标准焓差室测试中间补气系统与单级压缩系统在不同制热工况、APF基本工况下的系统性能。试验结果表明:中间补气系统可在室外温度低于-15℃时正常安全运行,在室外温度高于-15℃时,制热量相对于单级压缩系统有较大的提高,其提高幅度均大于12%;在额定制冷和中间制冷工况下,中间补气系统开启补气时,相对于不开启补气时,其EER值分别提高8.05%和13.67%,相对于单级压缩系统,其运行频率稍有降低,EER值分别提高2.05%和0.6%;在额定制热和额定低温制热工况下,中间补气系统相对于单级压缩系统制热量与功率均有较大提高,而系统COP相差不大;在中间制热工况下,中间补气系统相对于单级压缩系统,其COP可提高7.88%中间补气系统的APF值为3.85,相对于单级压缩系统的3.68,提高幅度达4.62%。     

补气增焓系统中补气量控制方式的应用分析

补气增焓系统在低温热泵领域得到越来越广泛的应用,在补气增焓技术的实际应用中,如何控制补气量是系统高效运行的关键。本文结合市场上产品应用现状,对使用电子膨胀阀同时控制排气温度和补气过热度、热力膨胀阀控制排气过热度及电磁阀控制排气温度这3种常用的补气量控制方式的优缺点及使用成本进行对比分析,并进一步通过试验定量地研究其应用效果。结果表明:以补气过热度为控制目标的系统制冷能力最高,高于其他方式10%以上。     

基于喷气增焓技术的轻型商用变频空气源热泵的研究

针对寒冷区域的供热需求,结合喷气增焓技术,研发一款在低环境温度下高制热能力输出的轻型商用变频空气源热泵。测试该系统在低环境温度工况下的性能,并与传统制热循环进行比较。测试结果表明,制热时喷气增焓系统存在最佳中间压力并实现制热时最大能力输出;在室外环境温度为-25~7℃时,喷气增焓系统比原系统在制热能力上均有较大的提高,有效拓展了系统的低温运行范围;在室外干/湿球温度-15℃/-16℃条件下,喷气增焓系统制热能力可达到系统额定制热能力的100%,在压缩机运行频率为100 Hz时,喷气增焓系统的COP可达到2.07,较对应工况下无补气系统COP提升10.5%;在室外环境温度为-20℃且压缩机运行频率为100 Hz时,喷气增焓系统COP较原系统提升6.2%;喷气增焓系统排气温度比原系统低,系统低频运行时排气温度差值较大。     

多联机性能测试环境实验室的研制

依据国家标准"GB/T 18837-2002多联式空调(热泵)机组"和某空调电器有限公司技术协议要求,研制了一套25HP小型多联机综合实验室。在实验室中,主要采用了"空气焓差法"的测试方法,结合PID的控制,使实验室能满足多联机性能测试的温、湿度等技术要求,实现对多联机性能的测试。试验证明,被控参数均达到标准要求,能很好地满足多联机的试验需要。     

浅析旋转式压缩机补气增焓技术

在低温环境下传统的空气源热泵系统的制热能力大幅衰减,制热量将小到无法满足这些地区的冬季采暖需求,而且随着环境温度的降低,系统COP急剧下降,压缩机的压比越来越大,导致排气温度不断升高,长期运转必然会严重损坏压缩机,为了使热泵在低温环境下也能高效、可靠地运行,国内外工程技术界进行了大量的研究,将喷射增焓技术应用于压缩机中。该文针对旋转式压缩机喷气增焓技术,从国内外申请趋势分析及专利产出国分布等方面分析了该领域全球专利概况,并重点从主要技术分支及其申请量分布、各技术分支技术演进等方面分析了该领域技术分支及演进。     

高温制冷家用空调器性能研究

家用普通热泵型空调作为一种高效、节能、便捷的空气调节装置,在人们的日常生产、生活中扮演着重要的角色。近年来全球气候异常,多地连续出现高温酷热天气,人们生产、生活条件恶化。夏季恶劣工况对家用空调器的高温制冷性能提出了更高的要求。文中提出了利用补气增焓（REID）的办法来有效解决空调器高温制冷问题,从理论上分析了补气增焓对空调系统高温制冷性能的影响,实验研究了补气增焓空调系统在高温工况下的性能,对高温制冷空调产品的设计及新环保冷媒R32的应用起到指导作用。     

Generic simulation model of multi-evaporator variable refrigerant flow air conditioning system for control analysis

Generic simulation models noted as AGM-I and AGM-II for performance and control analysis of variable refrigerant flow (VRF) systems were developed. Firstly, simulation models from component to whole VRF system were addressed. Then the simulation models were validated using experimental data reported in an open literature. The average error percentages to predict system cooling capacity, energy consumption and COP are 4.69%, 4.64%, 1.19%, respectively. Finally, tests were carried out. Results show that the developed models are fast computing and evaporator-number independent. From the computation speed point of view, the AGM-I is more suitable for multi-evaporator VRF system, while the AGM-II is more suitable for the one evaporator VRF system. Test results also show the system models good ability responding to varying conditions, including inlet air temperature of the evaporator, outdoor air temperature, opening of the EEVs and compressor speed, which are all very important variables for the control analysis.     

不同气候区域对多联机空调能效标准指标的影响

随着多联机系统的发展与普及,对多联机产品能效评价方法的研究也逐渐深入.目前,我国多联机3种主要能效评价指标(SEER、HSPF和IPLV(C))均与环境温度的发生小时数有关,本文从地理环境的角度出发,结合国际现行多联机能效标准的发展,分析不同气候区域对多联机空调能效标准指标的影响.通过分区进行能效评价是多联机能效标准研...     

Thermodynamic potential of using a counter rotating novel axial impeller to compress water vapor as refrigerant

This paper investigates the thermodynamic potential of using multi-stage variable speed counter rotating axial impellers as part of a water chiller system to compress water vapor (R718) as refrigerant. For this multi-stage compressor a modified cycle with an intercooling strategy is used between stages. Multi-stage compression with flash intercooling results in at least 30% improvement of coefficient of performance (COP) at full load compared to conventional refrigerants like R134a. Novel axial composite impellers, manufactured at extremely low cost, are proposed to take the compression role. To predict this counter rotating axial impeller’s thermodynamic capacity, a numeric CFD approach is taken in the study to generate steady state performance maps; based on the maps it is found that maximum pressure ratio of single counter rotating stage reaches 1.3 with isentropic efficiency around 70%. The aim of this study is to demonstrate that this counter rotating novel axial impeller has the potential to produce a high enough pressure ratio, and with a practical isentropic efficiency, in a multi-stage compressor to compress water vapor as refrigerant.     

多联机系统制热工况下的制冷剂充注量故障诊断模型——基于多层卷积神经网络

本文提出一种基于卷积神经网络的故障诊断模型,并通过正交试验优化了3层网络的卷积核和神经元数目,利用图形化的多联机(VRF)系统制冷剂充注量故障实验数据训练了多层卷积神经网络,评估了本模型的故障诊断性能。结果表明:该"数据图形化-多层卷积神经网络"方法建立的模型能够有效进行多联机制冷剂充注量故障诊断,20个输入特征时,对9类故障诊断总正确率最大为91%,比传统BP神经网络达到更高的诊断精度。该方法首次利用卷积神经网络完成了VRF制冷剂充注量故障诊断,为相关研究的拓展奠定了基础。     

变流量多蒸发器制冷系统仿真通用快速算法研究

针对目前变流量制冷系统仿真算法设计研究不多以及通用性不足,提出一种物理意义明确且通用的迭代算法（简称为ALG-I）及其变种算法（简称为ALG-II）。对迭代变量的选择,迭代判据的确定给出了操作准则和方法。对算法流程的关键步骤进行了详细阐述。ALG-I与ALG-II具有相似特性但需要的仿真时间不同。仿真结果表明,提出的算法能适用于任意数目蒸发器的变流量制冷系统仿真,且仿真时间未随蒸发器个数增大而急剧增加,表明算法具有与蒸发器个数无关的通用特性。从控制分析需要快速响应的要求来看,对于一拖一系统, ALG-II比ALG-I有优势,而对于一拖多系统,ALG-I则比ALG-II有优势。最后,系统对连续变化的控制变量（包括膨胀阀开度及压缩机转速）的合理响应表明提出的算法可以有效地用于VRF系统的能耗与控制仿真。     

Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions

This paper reviews the major research on refrigerant injection techniques in detail. Liquid and vapor refrigerant injection techniques are discussed and compared. The current research on refrigerant injection techniques falls into two categories: system level research and component level research. The system level research is focused on low ambient temperature heating, heat pump water heating, high ambient temperature cooling, cycle comparison, and control strategy development. Internal heat exchanger and flash tank cycles are the two typical cycles for refrigerant injection. These two cycles are discussed and compared in detail. The component level research is focused on employing different types of compressors, variable speed compressors, the injection process, and the flash tank. Different types of compressors employing refrigerant injection are presented. Based on the literature study, the potential future research directions are presented and discussed. The flash tank cycle control strategy and refrigerant charge management strategy are worth further research efforts. Compressor design can be improved in order to optimize the performance with refrigerant injection. The appropriate design of flash tanks plays a vital role in achieving appropriate two-phase flow patterns in the flash tank. Computational Fluid Dynamics (CFD) modeling can be a useful tool to facilitate the design of the flash tank.     

Effects of liquid refrigerant injection on the performance of a refrigeration system with an accumulator heat exchanger

Liquid refrigerant injection technique can be a very effective method for controlling subcooling and the compressor discharge temperature of a refrigeration system at high ambient temperatures. In this study, the effects of liquid refrigerant injection on the performance of a refrigeration system with an accumulator heat exchanger were investigated by varying the liquid injection rate at the conditions of constant expansion valve opening in the evaporator and constant total flow rate. During the tests, the ambient temperature was maintained at 43 °C. With the increase of the liquid injection rate, the subcooling at the inner heat exchanger outlet increased and the superheat at the accumulator outlet decreased. However, unacceptable results such as the increase of the compressor discharge pressure and decrease of the system performance were also observed depending on the control method applied. To obtain high system performance and reliability, optimum control methods for liquid injection in the accumulator heat exchanger are suggested. The liquid injection technique for the refrigeration system with an accumulator heat exchanger was found to be an effective method for controlling adequate subcooling and the compressor discharge temperature of the refrigeration system at high ambient temperatures.     

基于Boosting的多联机制冷剂充注量故障诊断集成模型

多联机空调系统被广泛用于各种公共建筑物,一旦发生故障会导致舒适性降低,能耗增加。制冷剂充注水平是影响空调系统高效运行的重要参数。本文提出一种基于Boosting集成算法的故障诊断模型,以制冷剂充注量故障为研究对象,将逻辑回归、决策树、随机森林、支持向量机和BP神经网络等5个基分类器集成,使用卡方检验进行特征选择,并使用制冷、制热模式的实验数据建立诊断模型。结果表明:基于Boosting的集成模型能高效检测多联机制冷剂充注量的故障,准确率高达96. 8%,相比于传统故障检测方法,大幅提高了诊断模型的响应速度、准确度和实用性。     

基于SVR-OCSVM模型的多联机系统用能评估与诊断

直接根据多联机系统能耗数据的变化来判断导致能耗大幅波动的因素是很困难的。本文提出一种有效的可用于多联机系统的能耗评估与诊断方法:将支持向量回归(SVR)算法与单类支持向量机(OCSVM)算法相结合,首先通过提取系统能耗数据集特征,去除非稳态数据,根据提取的特征变量与系统能耗建立SVR模型,预测多联机系统能耗;然后将实际能耗值与预测能耗值之差和之比分别标准化,作为输入变量,建立单类支持向量机(OCSVM)模型进行样本判别,确定是否为导致系统能耗异常的原因,以此评估诊断多联机系统能耗情况。本文基于多联机能耗正常的数据集构建了能耗评估与诊断模型,并用多联机系统能耗异常数据集验证了模型的可靠性。结果表明:基于SVR-OCSVM模型的能耗评估与诊断模型具有较高的准确度,基本能达到70%以上。     

R32经济器系统涡旋压缩机中间补气参数的分析与优化

为了优化带经济器的R32空气源热泵系统的制热性能,结合涡旋压缩机的结构以及实际运行特点,本文利用MATLAB建立了系统的数学模型,并通过实验数据验证了仿真结果,研究了在不同环境温度下系统的补气压力、准一级压缩内容积比对相对喷气量的影响.研究结果表明:经济器系统较普通热泵系统,更适宜在环境温度低于-10 ℃的工况下运行;...