基于k-means聚类的地源热泵机组运行策略优化研究

以上海某地源热泵为研究对象,基于长期实测数据对全年工况性能特性进行了研究。通过k-means对全年工况的日逐时负荷进行聚类分析,获得采暖、制冷和过渡季节等不同季节最佳族数及对应族下典型日负荷曲线特性。构建地源机组的性能仿真模型,通过实测数据获得模型相关参数值。分别以最优制热制冷性能系数为目标,建立了运行负荷配比优化模型,并将模型应用于上述不同季节典型工况,对各典型工况下的运行策略进行优化,获得各工况下最优运行策略。通过与实测数据的对比,运行策略优化有效提高了热泵系统的能效。     

带喷射器的直膨式太阳能辅助热泵的理论研究

将喷射器应用于直膨式太阳能热泵,通过热力学第一定律和第二定律进行理论研究。分析了喷射器的接受室压降和太阳辐照强度对喷射器的性能及系统性能的影响,并对系统中各部件的火用损和火用损率进行了分析。结果表明:在本文设计模拟工况下,优化的循环系统性能要优于常规循环,COP最大提高率为10.84%,制热量最大提高率为24.17%,接受室存在最优压降使得系统性能最优,太阳辐照强度的增加使得系统性能得到优化,集热器/蒸发器的火用损占比最大,集热器/蒸发器与压缩机的节能潜力最大。     

VRF空调系统部分负荷特性的实测研究

本文通过搭建人工气候室实验台,对某一拖六变制冷剂流量(VRF)空调系统在制冷工况、部分负荷工况下的运行特性进行了实测研究。研究表明,VRF系统在部分负荷工况下具有较高的系统COP,且在负荷率为40%～50%区间内COP最高;在一定负荷率工况下,室外空气温度每升高10℃,系统COP降低0.6～0.8。在该系统定蒸发压力的控制模式下,各室内机的负荷不均匀指数对系统COP的影响很小。     

行业和地方标准中的COP与EER

通过中华人民共和国行业标准和地方标准中有关COP和EER的研究,分析了行业标准和地方标准中的COP和EER的术语解释和其他条文涉及的COP、EER的解读。行业标准中COP表示为制冷性能系数,而EER为制冷能效比或冷源系统能效系数;地方标准中COP既用来表示单一的制冷性能系数或制热性能系数,也用来表示制冷及制热性能系数;EER用来表示制冷或制热能效比。     

重庆市地表水源热泵系统运行性能研究

本文选取重庆市作为研究对象,对12个地表水源热泵系统的实际运行情况进行了分析。研究表明:地表水源热泵夏季制冷工况各系统平均COP可达3.53,冬季制热工况约为3.28,具有很好的运行效果;但在同一工程中冬夏工况转换后系统COP波动较大,且与机组COP之间的相关性并不显著,即高效机组不等于高效系统;当实际运行参数与设计计算参数趋于一致时,绝大多数系统可以实现较好的运行效果。     

地源热泵系统检测及能效评估——以汇丰凯苑公寓式酒店为例

以汇丰凯苑公寓式酒店地源热泵系统为对象,按照相关标准的规定,对该系统冬、夏两季工况的运行参数进行检测,计算热泵机组的制冷能效比EER、制热性能系数COP和热泵系统的制冷能效比EER_(sys)、制热性能系数COP_(sys),并对系统进行综合能效评估。结果表明:汇丰凯苑公寓式酒店地源热泵系统运行可靠,总体节能性和环保效果较好。     

环境参数对回热空气制冷系统COP及能效最优压缩比的影响分析

为配合加强基加利修正案中氢氟碳化物的管控,环境友好型制冷空调系统的研究成为热点。针对以空气为工质的制冷系统,为研究系统性能系数(COP)及其达峰的最优压缩比,本文建立了回热直流高压空气制冷系统COP计算模型,探讨分析了环境温度、压力及相对湿度等参数对系统COP与能效最优压缩比的影响。结果表明：降低环境温度、增大环境压力可降低系统的能效最优压缩比并提高制冷COP,且环境压力升高可显著减少膨胀过程的凝冰量;环境空气相对湿度对能效最优压缩比及系统制冷COP影响较小。     

基于温度多元线性回归模型的空调制冷站在线预测控制方法研究

从实际应用角度出发，以制冷站全局COP为优化目标，综合考虑制冷站整体特性及各组件相互耦合特性，提出了一种基于多元线性回归模型的制冷站预测控制方法。该模型的输入变量为冷水进出口温差和冷却水进出口温差，分别对应冷水侧和冷却水侧的运行特性，输出变量为制冷站全局COP,能够反映制冷站系统的综合特性。该模型结构简单、输入参数易获取、可复制性高，可在线应用于大多数制冷站系统。试验结果表明，该预测控制方法可有效提升制冷站整体运行能效。     

不同控制策略下的土壤源热泵系统夏季工况实验研究

在上海地区完成闭式冷却塔-土壤源热泵系统不同控制策略下的夏季实验。实验结果表明:在连续制冷情况下,加入冷却塔能有效改善系统COP,降低土壤温升。不同控制策略对于上海地区制冷系统COP和土壤温升的改善差异不同。在上海典型夏季工况下长期制冷,夜间冷凝温度控制对降低土壤温升和节能效果明显,但随着冷凝温度的增加,效果越差。较优控制策略选择为控制策略3-夜间设定温度29℃控制,该控制策略下机组COP最大值增幅16%,最小值减幅24%;系统COP最大值增幅16%,最小值减幅8%。地下埋管埋深30 m、45 m和60 m处,土壤温升降低最大,分别为64%、64%和63%。     

国标中的COP与EER

通过对中华人民共和国国家标准中的COP和EER对比研读,分析了国家标准中的COP和EER的术语解释。COP既用来表示单一的制冷性能系数或制热性能系数,也用来表示制冷及制热性能系数;EER则用来表示制冷能效比,且EER不是独立出现,与此对应的是用来表示制热性能系数COP。     

A review on performance improvement of an absorption refrigeration system by modification of basic cycle

The vapour absorption refrigeration system is not so much used commercially because of its low performance. The performance of an absorption refrigeration system is required to make it an efficient alternative of vapour compression refrigeration systems. This paper reviews different research on modification of absorption systems contributing to enhance the performance of absorption refrigeration systems. This study suggests that the performance of absorption refrigeration is improved by using double-effect and semi-generator absorber solution heat exchanger arrangement. The coefficient of performance of absorption refrigeration is also improved by the combination of different refrigeration cycles (hybrid refrigeration cycle) such as compression–absorption and ejector–absorption.

Abbreviations: COP: coefficient of performance; GAX: generator absorber solution heat exchanger; ARS: absorption refrigeration system; ECOP: ecological coefficient of performance; CAHP: compression-assisted absorption heat pump     

列车空调用空气循环制冷系统的对比研究

本文的目的是研究空气循环制冷系统在我国列车空调工况下的运行特性,得出各种循环的优缺点,为我国列车空调用空气循环制冷系统的研制提供依据。主要针对常用的三种可行性方案进行了对比研究,分析了三种循环的工作原理,并对各部件和系统建立了热力学模型,得出了各种循环在我国列车工况下的运行特性。结果表明:三种循环都存在最佳膨胀比,转动部件的等熵效率对循环的性能有显著影响,在列车空调工况下,开式负压循环具有较高的制冷系数。     

Analysis on energy saving potential of integrated supermarket HVAC and refrigeration systems using multiple subcoolers

The paper presents a model-based analysis on the energy saving potential of supermarket HVAC (heating, ventilating, and air-conditioning) and refrigeration systems using multiple subcoolers among the high-temperature HVAC system, the medium-temperature refrigeration system, and the low-temperature refrigeration system. The principle of energy reduction is to have the higher COP (coefficient of performance) system generate more cooling capacity to increase the cooling capacity or reduce the power consumption of the lower COP system. The subcooler could be placed between the medium-temperature and low-temperature systems, between the high-temperature and medium-temperature systems, and between the high-temperature and low-temperature systems. All integration scenarios of adding one, two and three subcoolers have been investigated. The energy saving potential varies with the load ratio between high-, medium- and low-temperature systems, COP of three systems, and the “on-off” duty time of HVAC system. The optimal sequence of adding subcoolers is also proposed.     

复合喷射制冷循环及其新技术

对3种复合喷射(压缩--喷射，吸收--喷射和吸附--喷射)制冷循环进行了理论分析，认为单一循环制冷系统加喷射器(泵)后的复合循环系统的COP值有所提高；探讨了提高复合制冷循环系统COP的几个关键问题，包括喷射器的设计、工作温度、冷凝温度、蒸发温度等，并对复合制冷循环系统的发展作了展望。     

Performance of a new refrigeration cycle using refrigerant mixture R32/R134a for residential air-conditioner applications

In this paper, a new refrigeration cycle (NRC) using the binary non-azeotropic refrigerant mixture R32/R134a is presented, which can be an alternative refrigeration cycle applied in residential air-conditioner. In the NRC, refrigerant circuit of the evaporator is separated into two branches. Because the non-azeotropic mixture has the characteristic of temperature glide, an important benefit of such configuration is that the Lorentz cycle can be realized. Compared with that of conventional cycle configuration, the new cycle efficiency can be improved. The calculating results show that, in the conventional refrigeration cycle (CRC), the mixture R32/R134a has a close performance to that is obtainable with pure refrigerant R22. However, the mixture R32/R134a in the NRC will result in a better performance. The maximal COP can be improved in a range of 8–9% over that of the CRC, and the volumetric refrigerating capacity can be approximately increased by 9.5%.     

Magnetic refrigeration: a promising new technology for energy saving

Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magnetocaloric effect. The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative refrigeration). In this paper, attention is directed towards the near-room-temperature range. We compare the energetic performance of a commercial R134a refrigeration plant to that of a magnetic refrigerator working with an AMR cycle. The comparison is carried out by means of a mathematical model. In these simulations, we consider different solid magnetic refrigerants, namely, Gd, Gd_0.95Dy_0.05, Gd_0.9Tb_0.1,Gd₅Si₂Ge₂, MnAs_0.9Sb_0.1, and MnAs_0.95Sb_0.05. We compared two different geometries of the regenerator: a porous medium and a flat plate. In the former, the Coefficient of Performance (COP) of the AMR cycle is better than that of the vapour compression plant only in the low mass flow-rate range. Whereas in a flat plate regenerator, the COP of the AMR cycle is better than that of the vapour compression plant only in the high mass flow-rate range.     

吸收循环冷水大温差系统理论效率分析

为实现吸收循环冷水大温差制冷系统节能运行，提出简单吸收循环、双蒸发器循环及双蒸发器双吸收器循环3个方案，分别建立了各方案的联合卡诺循环模型，并根据可逆过程热力学原理，完成了理论COP的推导，定量分析和比较了各方案。     

Optimisation of the evaporator of a refrigerator employing hydrocarbon as a refrigerant

ABSTRACT

The refrigeration and air conditioning system is a booming research in the research area. In refrigeration, the scientists focus on the new refrigerant in order to reduce the global warming potential (GWP), high coefficient of performance (COP) and meet zero ozone depletion potential (ODP). Not only the new refrigerant as a solution to attain zero ODP, high COP and at the same time to optimise the design of refrigeration system to meet ODP and COP as a required level. This paper aims to optimise the design of a double refrigerator evaporator for a refrigerator employing non ozone-depleting hydrocarbon refrigerant using brine as a secondary solution with a low GWP. It is done by numerical modelling followed by the parametric modelling using CATIA V5.     

极化制冷油添加剂在制冷机中的节电作用

阐述了PROA添加剂(polarized refrigerant oil additive)的润滑和增强盘管传热的原理，对PROA添加剂在工程中的应用进行了测试，测试结果表明制冷机(活塞式)的COP值明显提高，而且制冷机使用年限越长，加入PROA后制冷机(活塞式)的COP值增加越明显。     

Performance investigation of ozone-friendly R404A and R507 refrigerants as alternatives to R22 in a window air-conditioner

In this study, experimental research was carried out to investigate the performance of R22 and its ozone-friendly alternative refrigerants (R404A and R507) in a window air-conditioner. The performance parameters of the system using R22 were considered as benchmarks and those obtained using alternative refrigerants were compared. Experimental results showed that R22 had the lowest pressure ratio and discharge temperature closely followed by R507. The average discharge temperature obtained using R507 and R404A were 4.2% and 15.3% higher than that of R22, respectively. The lowest compressor power and energy consumption were obtained from R507 retrofitted system. Also, the highest refrigeration capacity and coefficient of performance (COP) were obtained using R507 in the system. The average refrigeration capacities of R507 and R404A were 4.7% higher and 8.4% lower than that of R22, respectively, while the average COP of R507 increased by 10.6% and that of R404A reduced by 16.0% with respect to that of R22. Generally, the investigation has revealed that R507 can be used successfully as a retrofitting refrigerant in existing window air-conditioners originally designed to use R22 in the event of HCFC phased out.