R410A与R22在家用空调中的应用比较(2)

本文部分（2）利用Bin参数分析法对R410A与R22空调的全年运行耗电进行计算，采用寿命期气候性能（LCCP）指标对R410A与R22的温室效应总体影响进行考查，同时对R410A与R22空调的生产成本进行比较。结果表明R410A空调由于运行效率高，在使用过程中可以显著节约耗电和运行费用，而且随着原材料价格的上涨和R410A压缩机生产能力的扩大，R410A与R22空调具有相近的生产成本；同时，通过减小温室间接效应以及空调的制冷剂充灌量或泄露量，与R22相比，R410A反而还会有利于降低对气候变暖的影响。     

Use of nanoparticles to make mineral oil lubricants feasible for use in a residential air conditioner employing hydro-fluorocarbons refrigerants

The application of nano-fluids in refrigerating systems is considered to be a potential way to improve the energy efficiency and reliability of HVAC&R facilities and to make economic the use of environment-friendly refrigerants. In this paper, we report a method that uses nanoparticles to enhance the energy efficiency of retrofitted residential air conditioners (RAC) employing HFCs as alternative refrigerants. The reliability and performance of RAC with nanoparticles in the working fluid have been investigated experimentally. A new mineral-based nano-refrigeration oil (MNRO), formed by blending some nanoparticles (NiFe₂O₄) into naphthene based oil B32, was employed in the RAC using R410a as refrigerant. A method showing how to disperse the NiFe₂O₄ nanoparticles in the mineral oil refrigeration lubricants is presented together with an investigation of their stability. The solubilities of the new MNRO in R134a, R407C, R410a and R425a were measured. The performances of the RAC, such as the cooling/heating capacity, the power input and the energy efficiency ratio, were determined. The results indicate that the mixture of R410a/MNRO works normally in the RAC. The cooling/heating EER of the RAC increased about 6% by replacing the Polyol-Easter oil VG 32 lubricant with MNRO.     

R410A与R22在家用空调中的应用比较(1)

R410A不破坏臭氧层,是一种可以长期替代R22的绿色环保制冷剂,现已在家用空调中得到日益广泛的应用。本文分别对R410A与R22的热力性能,对4台具有可比性的R410A与R22空调的系统性能即制冷量和能效比进行比较考察,结果表明R410A具有良好的热传递与流动特性,有利于减少空调换热器尺寸、提高系统运行效率。     

空气源热泵的稳态仿真及性能比较

建立了空气源热泵的稳态仿真模型,得出了R22和其替代工质R32／R134a系统循环性能随工况的变化曲线。相同工况下两种工质性能比较结果表明,采用混合工质的系统制热性能系数高,制热量低,耗功量小,混合工质替代纯工质有一定的节能优势。     

R32用于喷气增焓热泵热水器中可行性研究

理论分析了R32作为空气源热泵热水器制冷剂的可行性,并设计搭建带有喷气增焓装置的实验系统,分别充注R32和R410A制冷剂进行性能对比测试。实验结果表明:对于本实验系统R410A的最佳充注量为1.4 kg,R32的最佳充注量比R410A减少约25%,且名义工况下R32热泵系统的COP要高出R410A热泵系统约4.2%;低温工况下,采用双级压缩系统的压缩比最高在3左右,有效缓解了常规热泵系统低温工况下压缩比过高的问题;低温工况下,R32热泵系统的COP明显高于R410A热泵系统。     

Integration of variable refrigerant flow and heat pump desiccant systems for the heating season

Integration of the variable refrigerant flow (VRF) and heat pump desiccant (HPD) systems was investigated in a field performance test for a heating season. The HPD systems use only the moisture in the outdoor air and return air to humidify the indoors during ventilation in the heating season. Three different operating modes: non-ventilated, HPD ventilation assisted and HPD ventilation-humidification assisted VRF systems were investigated. It was found that the VRF systems provided an average of 93.5% of the total heating energy for the HPD ventilation assisted mode. The remainder was the recovered heat by the HPD systems during ventilation. The VRF systems provided an average of 46.8% of the total heating energy for the HPD ventilation-humidification assisted mode. The remainder was covered by the HPD systems which provided additional sensible and latent heating. Overall, among the three operating modes, it is concluded that the HPD ventilation-humidification assisted VRF outdoor units consume less energy than the HPD ventilation assisted ones (about the same energy as the non-ventilated ones), while providing the best indoor thermal comfort and indoor quality conditions. For the total system, the HPD ventilation-humidification assisted VRF systems consume less energy than the HPD ventilation assisted ones.     

替换R290的热泵型空调器供暖实验研究

为探讨热泵型空调器更换R290后的供暖特性,在重庆地区开展了供暖工况下充注R290空调器与原R22空调器的对比实验,测试了空调器的送回风温湿度、耗电量、风量等数据。研究了两组空调器的送回风温湿度差异及与室外温度变化的关系,比较了2台空调供热量、耗电功率及COP等数据。结果表明:在重庆地区热泵型空调中替代充注R290后,空调器制热效果良好,室内空气温湿度与原空调器处理的空气温湿度较为接近;但由于制冷剂质量流量减小,平均供热量降低14.6%;尽管COP整体降低了7.5%,但在运行稳定后COP能接近原空调器。     

五棵松棒球场空调设计分析

五棵松棒球场是2008年奥运会棒球比赛场地,其空调系统采用数码涡旋多联机组,冷媒为环保的R410A。     

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.     

Performance studies of R433A in a direct expansion solar-assisted heat pump

ABSTRACT

Energy assessment of a simple direct expansion solar-assisted heat pump system has been experimentally assessed with R433A as a possible alternative to R22. An artificial neural network integrated genetic algorithm model was developed to assess the performance system. The data obtained from the experimentation at different ambient conditions are used as the training data for the ANN network. The back propagation learning mechanism with variants Lavenberg-Maguardt with 20 neurons in the hidden layer were used in modelling of ANN. The values obtained from the analysis using ANN are optimised further by integrating the ANN procedure with GA. The results indicated that R433A has 6.4% and 1% lower instantaneous compressor power consumption and heating capacity compared to R22. Energy performance ratio of R433A was found to be about 5.67% higher compared to R22. The results confirmed that R433A can be used as a possible alternative to R22 DX-SAHP systems.     

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%.     

过热度对翅片管蒸发器性能影响的模拟研究

利用EVAP-COND软件对三排管翅片管蒸发器进行模拟计算。选取3种制冷剂R22、R134a和R410A,4种不同的流路布置方式,分别计算不同制冷剂出口过热度下蒸发器的总换热量,对模拟结果进行分析对比,研究出口过热度对翅片管蒸发器换热性能的影响,得出有利于指导蒸发器优化设计的结论。蒸发器出口制冷剂过热度越大,制冷量越小;设计的4种流路布置方案中第二种方案最为合理;制冷剂R410A换热性能最佳,可以替代R22。     

新型环保制冷剂R1234ze/R600a PVTx性质

在Burnett原理基础上搭建了高精度PVT实验台,对新型环保混合制冷剂R1234ze/R600a进行了热物性测试。在温度范围为280.15~330.15 K时,测量了质量分数为80%/20%和75%/25%的R1234ze/R600a混合制冷剂的PVT性质,同时拟合出了相应温度与压力下该混合工质的密度与气体维里方程,为进一步研究该混合制冷剂作为新型替代制冷剂的性能提供了热物性参数。     

LCCP,一种全球气候变暖影响的评价指标

介绍了几种对全球气候变暖影响的评价指标，包括全球变暖潜值GWP、变暖影响总当量TEWI及寿命期气候性能LCCP。特别讨论了LCCP概念的内涵，以及它与GWP和TEM之间的关联和区别。综合介绍了使用不同制冷剂时单元式空调、冷水机组、商业制冷、汽车空调及家用冰箱等制冷空调设备的LCCP典型结果。     

Improvement of solar-electric compression refrigeration system through ejector-assisted vapour compression chiller for space conditioning in subtropical climate

In this study, improvement was made for the solar-electric compression refrigeration system by incorporating the ejector design to a conventional vapour compression chiller within the system. Through year-round dynamic simulation, the performances of the ejector-assisted vapour compression chiller (EAVCC) were evaluated under the intermittent and changing supply of solar energy in the subtropical climate. In addition, the effect of three common refrigerants, R22, R134a and R410A on the EAVCC was assessed and compared. It was found that the coefficient of performance of the chiller was increased and the total primary energy consumption of the system was decreased for all the three refrigerants, in which the degree of enhancement from R134a was the most significant. It was also noted that the effect of R410A on EAVCC was not apparent, and the overall system energy improvement was marginal. With appropriate ejector design and refrigerant selection of the solar-electric compression refrigeration system, the reduction potential of year-round primary energy consumption could be more than 5%. This would be certainly helpful in promoting the application of solar air-conditioning for building use in the subtropical climate.     

A thermodynamic analysis of a transcritical cycle with refrigerant mixture R32/R290 for a small heat pump water heater

In this study, a thermodynamic analysis on the performance of a transcritical cycle using azeotropic refrigerant mixtures of R32/R290 with mass fraction of 70/30 has been performed. The main purpose of this study is to theoretically verify the possibility of applying the chosen refrigerant mixture in small heat pumps for high temperature water heating applications. Performance evaluation has been carried out for a simple azeotropic mixture R32/R290 transcritical cycle by varying evaporator temperature, outlet temperature of gas cooler and compressor discharge pressure. Furthermore, the effects of an internal heat exchanger on the transcritical R32/R290 cycle have been presented at different operating conditions. The results show that high heating coefficient of performance (COP_h) and volumetric heating capacity can be achieved by using this transcritical cycle. It is desirable to apply the chosen refrigerant mixture R32/R290 in small heat pump water heater for high temperature water heating applications, which may produce hot water with temperature up to 90 °C.     

低温复叠机组中R404A/R23替代R22/R13的理论研究

本文采用R404A／R23替代R22／R13在低温复叠制冷机组中的使用。从理论上计算和比较分析了替代的可能性。结果发现从总体上而言,替代是可行的,对机组的效率、制冷量等方面的影响不大;但就具体的一些细节方面尚需做出改进,本文也做出了阐述。     

R22和R410A多联式空调机组经济配管长度理论研究

随着多联机的广泛使用,多联机配管长度对机组性能的影响成为业内人士关注的问题。配管长度的增加,虽然可以扩大多联机的作用域,但是同样带来了回油困难、制冷量衰减和系统需充注大量制冷剂的问题,造成了多联机在理论上具有节能潜力,而在实际使用中未必有效的现象。本文就机组配管长度对机组的影响进行了理论分析计算,讨论了多联机的经济配管长度。     

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

With the current movement towards net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a preliminary comparison of energy efficiency between the air-source VRF and GSHP systems is presented. The computer simulation results show that GSHP system is more energy efficient than the air-source VRF system for conditioning a small office building in two selected US climates. In general, GSHP system is more energy efficient than the air-source VRV system, especially when the building has significant heating loads. For buildings with less heating loads, the GSHP system could still perform better than the air-source VRF system in terms of energy efficiency, but the resulting energy savings may be marginal.     

空调常用制冷剂在微通道蒸发器中的性能分析

通过换热器优化软件设计了一款微通道平行流蒸发器模型,利用已验证的传热与压降关联式,在不同的模拟工况下研究分析了R22、R290(propane)、R134a、R410A、R1234yf在蒸发器模型中的传热与流动性能。结果表明:在质量流量一定的条件下,R290的换热量远高于其他制冷剂,是R22的1.63倍,R410A的换热量与R22相差无几,换热量最小的制冷剂为R1234yf;R290的充注量为147 g,仅为R22的72.4%,R134a的充注量最大,达到了221 g;制冷剂侧压降损失最大的R290,压降损失达到了75.4 k Pa。在理论换热量一定、质量流量不定的条件下,换热量最大的制冷剂是R134a,达到了8 500 W;充注量和制冷剂侧压降损失最小的制冷剂为R290,并且其换热量达到了8 230.4 W。