膨胀阀对陈列柜内温度分布影响的对比实验研究

对热力膨胀阀和电子膨胀阀控制下陈列柜内的温度分布做了实验研究。结果表明，在热力膨胀阀控制下，陈列柜内的温度分布情况与电子膨胀阀相差不大。在目前的实际应用中，热力膨胀阀基本能满足一般客户对陈列柜的使用要求，没有必要大规模进行电子膨胀阀的替代。     

热力膨胀阀与电子膨胀阀对分液性能影响的比较

本文通过比较蒸发器各回路之间的温差，对分液器在热力膨胀阀和电子膨胀阀控制下的分液性能做了实验研究。结果表明在电子膨胀阀控制下分液器的工作性能更好，而且还可以保持较小的蒸发器传热温差。     

电子膨胀阀与热力膨胀阀在低温装置中的比较研究

利用已有的多功能低温实验台,研究电子膨胀阀和热力膨胀阀在低温下的一些特性,对热力膨胀阀和电子膨胀阀在控温范围、过热度控制及控制精度等方面进行对比研究。     

不同类型膨胀阀对热泵热水器性能影响的研究

目前热泵热水器大多采用热力膨胀阀作为系统的节流元件,但是其仅能控制过热度,而无法根据其他热力参数对系统进行更加优化的控制.首先建立了热泵热水器稳态数学模型,搭建了实验装置,并将模拟结果与实验进行了对比,验证了模型的精确性.然后,对系统中采用热力膨胀阀和电子膨胀阀等两种情况进行了模拟分析,结果显示,采用电子膨胀阀后可有效...     

超市冷冻冷藏陈列柜改造方案探讨

为了优化超市冷冻冷藏陈列柜的设计,提出将具有电磁阀和温控器功能的MEMS膨胀阀代替传统的热力膨胀阀作为节流装置,以克服热力膨胀阀调节速度慢、精度低和功能单一的缺点。试验结果表明,经过优化设计的MEMS膨胀阀不仅能够代替电磁阀起到系统的启停作用,还可以代替温控器检测柜内空气温度,并且通过对过热度控制逻辑的改进,实现冷冻冷藏陈列柜10.1%的节能。     

制冷装置中膨胀阀的对比研究

为验证自行开发的电子膨胀阀和采用单片机开发的实时控制器的控制效果,针对热力膨胀阀、步进电机型膨胀阀、电磁阀型膨胀阀,进行了多个制冷系统冷启动和稳定工况下变负荷控制的实验研究。结果表明相对于传统的热力膨胀阀,电子膨胀阀更适用于系统综合控制器;连续调节型的执行机构比离散调节型的执行机构更容易使过热度稳定;积分环节大大改善了过热度的控制品质。自行开发的电子膨胀阀和控制器,性能价格比高,与国外同类产品相比,实际的控制效果也有较明显的提高。     

电子膨胀阀在冷藏库制冷系统中应用的展望

本文通过阐述电子膨胀阀与冷藏库的传统节流装置——热力膨胀阀之间的差别，并从节能和机电一体化的角度出发，分析了电子膨胀阀在冷藏库制冷系统中应用的可行性。     

风冷式热泵机组应用中电子膨胀阀与热力膨胀阀的比较

本文通过对电子膨胀阀与常规的热力膨胀阀在性能与功能上的比较,认为在风冷式热泵机组中,采用电子膨胀阀的更能体现出其优越性和灵活性.     

电子膨胀阀在低温系统中的应用研究

研究了电子膨胀阀在低温系统中的应用特性，并对热力膨胀阀和电子膨胀阀在相近工况下进行降温特性的对比性试验。根据实验结果进行分析，可以看出电子膨胀阀在低温条件下的控温曲线也是非常平稳的，并可调节电子膨胀阀的不同开度，使低温箱体达到不同的降温速率及终温。另外通过改变电子膨胀阀开度以及在箱体内加入不同的热负荷，研究了在变负荷条件下，对制冷系统循环参数的影响，尤其是对蒸发器、压缩机、冷凝器进出口温度的影响。     

电子膨胀阀在低温装置上降温特性的试验研究

为了研究电子膨胀阀在低温条件下的应用特性,研制了低温试验台,并在试验台上并联安装了电子膨胀阀和热力膨胀阀,对两种膨胀阀在相近工况下进行降温特性的对比性试验。根据实验结果进行分析研究,可以看出电子膨胀阀在低温条件下的控温曲线是非常平稳的,并可调节电子膨胀阀的不同开度,达到不同的降温速率及终温。另外通过改变电子膨胀阀开度,研究了在变开度情况下,对制冷系统循环参数的影响。     

商用制冷陈列柜能耗标准分析

制冷陈列柜,作为超市必备的一种制冷工具,已获得日趋广泛的应用。同时,制冷陈列柜属于高耗能产品,其耗电量达到整个超市耗电量的70％左右。因此,控制制冷陈列柜耗电量对节能工作具有重要意义。目前,世界上许多国家都制定了制冷陈列柜的能效标准（多为强制性）,并实施了能效标识制度。本文重点介绍澳大利亚、美国等国家及地区的制冷陈列柜能效标准及标识情况,并以此为依据对我国能效标准的建立提出意见。     

环境送风式冷藏陈列柜的开发研究

为解决传统陈列柜功耗过大的问题,搭建了环境送风式陈列柜试验台。试验结果表明,与传统陈列柜比较,环境送风陈列柜可实现良好的节能特性。由于可引入室外冷空气,无需压缩机制冷,能节省大量的能耗。但此种供冷方式受到室外环境温度的限制。     

陈列柜摆放位置对荔枝货架期品质的影响

目的研究不同销售方式及摆放位置对货架期荔枝果实品质变化的影响,为荔枝果实货架期保鲜和销售货架设计提供一定的参考。方法在敞开式陈列柜和常温货架上,以盒装的"怀枝"荔枝果实为实验材料,开展荔枝果实贮藏试验,研究货架期72h内荔枝果实分别放置在冷藏陈列柜不同位置和常温货架上品质的变化情况。结果在货架期内,冷藏陈列柜第4层和常温货架贮藏荔枝的果实褐变指数高于其他陈列位置,好果率低于其他陈列位置;冷藏陈列柜第4层的荔枝果实质量损失率的上升速率最快,72 h后上升至11.01%,其果皮色差a*值最小;第3层荔枝果实的质量损失率上升得最缓慢,其果皮色差a*值最大;常温货架荔枝的果皮色差L*值最大,其果肉的可溶性固形物含量和硬度最低;不同销售方式及摆放位置对荔枝果肉可滴定酸含量的变化影响不显著。结论在冷藏陈列柜中、上部摆放位置贮藏能相对更好地保证荔枝果实的销售品质,冷藏陈列柜的结构优化及其对温湿度场分布特性的影响将会是今后的研究方向。     

On the activation strategy of the chiller in water-loop self-contained refrigeration systems: An experimental analysis

Supermarkets require considerable amount of electricity and gas for refrigeration and maintenance of comfortable retail environment conditions. They are also responsible for a large amount of both direct and indirect CO₂ emissions. Nowadays advanced refrigeration systems for supermarkets can reduce both annual energy consumption and total equivalent warming impact. One of these advanced solutions is the water-loop self-contained refrigeration system, where the thermal power of each cabinet is rejected to a fluid-loop, refrigerated either by a dry-cooler or by a central chiller. In this study the performances of a real water-loop self-contained plant are analyzed to establish whether the activation of the water-loop chiller is energy effective or not varying the external air temperature. The activation strategy of the chiller is a crucial issue, which dramatically affects the energy performances of the whole system.     

敞开式食品冷藏陈列柜耦合节能的试验研究

本文对环境温湿度对陈列柜及空调系统的影响进行了试验研究。从耦合节能的角度考虑,结合环境温湿度对陈列食品温度的影响,试验分析环境因素对陈列柜及空调系统能耗的影响情况。试验表明,当系统在环境温度23℃,相对湿度55%工况附近运行时,陈列柜及空调系统总能耗较小,陈列柜及空调系统可以达到较好的耦合节能效果。     

微通道冷凝器在展示柜上的应用研究

针对卧式冷藏展示柜能耗较高,在环境温度升高时制冷效果下降等问题,提出采用传热系数较高的微通道换热器作为冷藏展示柜的冷凝器。实验对比结果表明:新改进的展示柜解决了高温工况下制冷效果下降和压缩机不停机等问题,展示柜的能耗也显著降低。在环境温度为16、25、32℃工况下空柜测试,与管外面积相差在3%以内丝管式冷凝器相比,微通道冷凝器分别节能11. 67%、24. 85%、45. 64%,开停比分别下降7. 20%、14. 90%、31. 70%。     

Theoretical study on a frost-free refrigerated display cabinet

This study deals with a frost-free refrigerated display cabinet, in which frosting can be retarded by dehumidifying the air before it enters the evaporator of the display cabinet via a desiccant-coated heat exchanger. Because the desiccant can be regenerated via the condensation heat of the refrigerant (which is exhausted into ambient air in conventional refrigerated display cabinets), the proposed system can achieve high energy efficiency. Calculation shows that the coefficient of performance (COP) of this system is 3.1 and the daily electricity consumption of the compressor is 10.5 kWh when the temperature (T_RA) and relative humidity (RH_RA) of the return air entering the evaporator are 12 °C and 0.6, respectively. Furthermore, it is found that T_RA and RH_RA significantly affect the COP: COP increases by about 115% when T_RA varies from 8 to 14 °C, and increases by 35% when RH_RA varies from 0.5 to 0.8.     

Development of a stability model for a vertical single band recirculated air curtain sealing a refrigerated cavity

Recirculating cold air curtains are used to seal the open front of all multi-deck refrigerated display cabinets commonly used in food retail. Infiltration through the air curtain has been estimated to be the source of between 78 and 81% of the total heat gain to the cabinet. More efficient air curtains would not only save energy but would enable more precise temperature control of the produce within the display cabinet, better preserving food quality. Curtain thickness, length, discharge temperature and velocity all influence the efficiency of the air curtain and design optimisation has until recently been largely empirical or has used complex CFD models.The aim of this study was to generate a design guide which would enable cabinet designers with limited fluid flow expertise to rapidly identify the most efficient air curtain design to seal any given cavity from fundamental measurements without any need for intensive computation.     

Experimental analysis of R-450A and R-513A as replacements of R-134a and R-507A in a medium temperature commercial refrigeration system

This work presents the experimental evaluation of R-513A (GWP = 573) and R-450A (GWP = 547) as R-134a (GWP = 1301) drop-in replacements and as R-507A (GWP = 3987) retrofits in a commercial direct expansion refrigeration system for medium temperature applications (2 °C). The evaluation covered 24-hour tests using a single-stage cycle with semi-hermetic compressor, an electronic expansion valve customized for each refrigerant and a commercial vertical cabinet with doors placed inside a climatic chamber. The tests were performed at three water dissipation temperatures (23.3, 32.8 and 43.6 °C). Experimental results indicate that R-513A and R-450A can operate with R-134a plants, with increments in energy consumption between −1.6 to +1.2% for R-513A and from +1.3 to +6.8% for R-450A, whereas in comparison with R-507A, R-513A offered reductions in energy consumption between 4.4 to 8.2% and R-450A between 0 to 3.3%. The paper analyzes the modification of the operating pressures/temperatures and the energy indicators using the four refrigerants.