跟踪:制冷赞助商:10.7商用餐饮制冷设备、制冷委员会、TC8:1容积式压缩机；TC3.1制冷剂和二次冷却器问题:乔治·卡扎奇博士，美国俄亥俄州代顿凤凰城集团有限公司ASHRAE研究员，商用制冷系统是导致制冷剂泄漏的最大因素之一，仅次于汽车空调。由于这个原因，它们成为氨和二氧化碳等天然制冷剂研究最深入的应用。 这些系统在过去10-15年中经历了实质性的演变，以适应氨和CO2的特性（氨的安全等级B2，CO2在某些条件下的低临界温度和高压），同时，成本和效率与HFC系统具有竞争力。研讨会通过专题演讲展示了这一演变的结果。1.在世界任何地方都能有效地利用二氧化碳制冷Klaas Visser，P.E.，附属公司，KAV Consultants Pty Ltd，Kangaroo Flat，澳大利亚本演示文稿探讨了蒸发式冷凝器/气体冷却器（EC/GC）的优点，其中冷却介质温度是环境湿球温度（AWBT），而不是空气冷却气体冷却器的环境干球温度。 在世界98%的气候条件下，28°C的AWBT发病率未超过1%。在28°C的AWBT下，相对容易实现气体冷却器CO2出口温度31°C，部分负荷下甚至30°C。这意味着使用EC/GC可以在全世界范围内运行高效的CO2制冷。2.零售食品环境用超低充量氨级联系统的设计和性能验证Karthick Kuppusamy、Heatcraft Kysor/Warren、COLUMBUS、G超市的天然制冷技术是由全球对能源和环境日益增长的关注驱动的。 能源效率、安全性和可靠性是超市系统设计的关键特征。在一家超市进行了现场试验，氨系统作为顶循环，以满足MT和LT制冷负荷。整个系统设计具有最先进的节能功能和0.75 Lbs/TR的超低氨气用量。简要概述了设计考虑因素和测试结果。第三方验证的HFC并排能量研究证明了氨的优越效率。 3.利用两相喷射器提高使用天然制冷剂的商业制冷系统效率的机会Stefan Elbel，博士，创新热解决方案成员，伊利诺伊大学Urbana-Champaign，Urbana，IL。天然制冷剂的GWP低，使其成为商业制冷的理想选择。跨临界CO2循环的一个重要特征是大量节流损失，这会对高温环境下的能源效率产生负面影响。 本演示文稿介绍了在苛刻的室外条件下提高COP的多种方法，重点将是利用两相喷射器。存在多种循环选项，允许喷射器集成，包括利用回收的能量卸载压缩机，在不同温度水平下提供冷却，并通过使用喷射器在液体再循环循环中驱动制冷剂过量供给来提高效率。4.制冷用成套氨/CO2系统合伙人Scott Mitchell，南加州爱迪生市Irwindale，CAT本演示文稿提供了安装在加利福尼亚州Irvine的成套氨/二氧化碳系统现场测试的最终结果。 该装置是北美首次安装的同类装置之一，它让我们了解了如何将天然制冷剂应用于以前未使用过的系统。该项目在2016年2月的《ASHRAE期刊》文章中发表。演示日期:2017年6月28日上午8:00-9:30运行时间:90分钟。这是一个zip文件，由与演讲者音频录制同步的PowerPoint幻灯片（录制的演示文稿）、幻灯片的PDF文件以及每个演示文稿的纯音频（mp3）组成。

Track: RefrigerationSponsor: 10.7 Commercial Food and Beverage Refrigeration Equipment, Refrigeration Committee, TC8:1 Positive Displacement Compressors; TC3.1 Refrigerants and Secondary CoolantsChair: Georgi Kazachki, Ph.D., Fellow ASHRAE, Dayton Phoenix Group, Inc., Dayton, OHCommercial refrigeration systems have been some of the largest contributors to refrigerant leaks, second to automotive air-conditioning. For this reason, they became the most intensely studied application for natural refrigerants, such as ammonia and carbon dioxide. These systems went through a substantial evolution in the last 10-15 years to accommodate ammonia and CO2 specific properties (safety class B2 for ammonia and low critical temperature and high pressures in certain conditions for CO2) and, at the same time, to be cost and efficiency competitive with the HFC systems. The seminar demonstrates the outcome of this evolution through the featured presentations.1. Doing It All Efficiently with CO2 Refrigeration Anywhere in the WorldKlaas Visser, P.E., Affiliate, KAV Consultants Pty Ltd, Kangaroo Flat, AustraliaThis presentation examines the benefits of Evaporative Condensers/Gas Coolers (EC/GCs) where the cooling medium temperature is the Ambient Wet Bulb Temperature (AWBT) and not the ambient dry bulb temperature as is the case with air cooled gas coolers. A 1% incidence AWBT of 28°C is not exceeded in 98% of the world's climates. At a AWBT of 28°C it is relatively easy to achieve a gas cooler CO2 exit temperature 31°C and even 30°C at part load. This means that efficient CO2 refrigeration may be operated all over the world with the use of EC/GCs.2. Design and Performance Validation of Ultralow Charge Ammonia Cascade System for Retail Food EnvironmentKarthick Kuppusamy, Heatcraft-Kysor/Warren, COLUMBUS, GANatural refrigeration technology in supermarkets is driven by growing global concerns around energy and environment. Energy efficiency, safety and reliability are key characteristics of supermarket system design. A field test is carried out on a Supermarket with ammonia system as top cycle catering to MT and LT refrigeration loads. The entire system is designed with state-of-the-art energy efficient features and ultra-low ammonia charge @ 0.75 Lbs / TR. A brief overview of design considerations and test results are presented. Superior efficiency of ammonia is demonstrated in a side by side energy study with HFC that is validated by third party.3. Opportunities for Utilizing Two-Phase Ejectors to Increase Efficiency of Commercial Refrigeration Systems Using Natural RefrigerantsStefan Elbel, Ph.D., Member, Creative Thermal Solutions and University of Illinois at Urbana-Champaign, Urbana, ILThe low GWP of natural refrigerants makes them great candidates for commercial refrigeration. An important characteristic of transcritical CO2 cycles are the substantial throttling losses that negatively impact energy efficiency at high ambient temperatures. This presentation introduces numerous ways of improving COP at demanding outdoor conditions, and the emphasis will be on utilizing two-phase ejectors. A variety of cycle options exist that allow integration of ejectors, including utilization of the recovered energy to unload the compressor, to provide cooling at different temperature levels and to improve efficiency by using the ejector to drive refrigerant overfeed in liquid recirculation cycles.4. Packaged Ammonia/CO2 Systems for RefrigerationScott Mitchell, Associate Member, Southern California Edison, Irwindale, CAThis presentation provides the final results from field testing of a packaged ammonia/carbon dioxide system installed in Irvine, CA. The unit was one of the first of its kind installed in North America and provides a glimpse at how natural refrigerants can be applied to systems where they previously were not used. The project was featured in a Feb 2016 ASHRAE Journal article.Presented:June 28, 2017, 8:00-9:30 AMRun Time: 90 min.This is a zip file that consists of PowerPoint slides synchronized with the audio-recording of the speaker (recorded presentation), PDF files of the slides, and audio only (mp3) for each presentation.