高热密度数据中心水冷解决方案

随着高性能服务器等I设备的应用,高热密度数据中心对机房制冷提出更高的要求。本文分析了传统机房空调制冷和机柜应用的现状,以及高热密度机柜的制冷特点,研究了几种机柜水冷制冷解决方案特点,并给出了一个方案测试结果,为高热密度数据中心制冷指出了解决方案和应用方向。     

分离式热管空调对机房温度控制效果的试验研究

为进一步研究用于数据中心机房节能减排的技术手段,利用热管原理,开发配套机柜使用的分离式热管空调。通过控制机柜的热负载功率,在实际应用场所测试分离式热管空调的出风温度和回风温度以评估其制冷效果,要求当每个机柜的热负载不大于7 kW时,机柜出风温度不高于27℃。测试数据显示:此类空调在控制机房温度上的效果显著,为该类产品的进一步开发提供依据。     

高热密度水冷机柜制冷系统的方案设计与运用

高热密度水冷机柜制冷系统能有效解决超级计算机刀片服务器的散热问题.系统包含初级和次级两个独立的水循环,通过具有智能热交换控制功能的热交换柜互相隔离,控制冷却水温度始终高于露点温度,从而防止机房内冷凝水析出的风险.全密闭式水冷机柜作为制冷和散热终端,柜内空气循环系统采用正面送风,背面排风的形式.系统具有制冷量大、制冷效率...     

高热密度水冷机柜制冷系统的方案设计与应用

高热密度水冷机柜制冷系统能有效解决超级计算机刀片服务器的散热问题。系统包含初级和次级2个独立的水循环,具有智能热交换控制功能的热交换柜使其互相隔离,控制冷却水温度始终高于露点温度,从而防止机房内凝结水析出的风险。全密闭式水冷机柜作为制冷和散热终端,柜内空气循环系统采用正面送风、背面排风的形式。系统具有制冷量大、制冷效率高、稳定可靠等特点。     

三种一体化机柜制冷方案的应用对比

传统的精密空调制冷方案存在诸多不足,已无法满足高热密度服务器机柜的散热要求。本文介绍的3种一体化机柜制冷方案单柜式、单列式、双列式,能够有效克服传统制冷方案的不足。3种方案的设计和散热循环工作原理有着不同特点,满足不同的应用需求。此外,以水冷式制冷为例进行测试对比,3种方案的冷量利用效率都在70%以上,比传统精密空调制冷系统提升10%~20%。     

热管型机房空调系统设计与分析

针对数据机房、基站全天候空气调节需求,提出一种新型热管型机房空调系统,并设计制造额定制冷量为13 kW的热管型机房空调样机,在标准焓差实验室进行性能试验。结果表明:当室内外温差Δt≥13℃时,可利用室外自然冷源构造出具有节能效益的准热管,在满足13 kW制冷能力前提下,EER提高5%~35%;当Δt≥23℃时,系统运行热管模式,EER提高35%以上;在不增加成本的前提下,热管型机房空调全年能效比(AEER)较具有同等能力定速型、变频型机房空调分别高40%和20%以上;该技术为低成本节能型机房空调产品的开发开辟新思路。     

浅述微模块数据中心制冷空调方案的选择

简述了微模块数据中心概念及发展现状,分别介绍了单柜微模块数据中心、单列微模块数据中心的系统组成及空调方案。假设一个组级微模块样本,以列间机房空调方案的数值为基准值,按照单机柜散热量为3 kW^10 kW的不同情况,分别计算出1~10个不同模块数量时下送风机房空调方案的面积比及运行功率比。应依据不同应用场景及机柜散热量选择合理的空调机组方案。     

应用CFD探索机房精密空调的最佳轮巡备份策略

制冷系统的建设是数据中心节能的关键。在数据中心用于冷却机柜热负荷的空调都留有一定的裕度,国标要求单台空调必须留有15％～20％的制冷余量。常规做法是对数据中心的设备进行N＋X冗余冷却,与此相对应的空调运行方案是轮巡备份。普通轮巡备份方案存在种种弊端,也缺乏科学依据。为避免轮巡备份的盲目性,应用CFD探索机房精密空调的最佳轮巡备份策略具有重要意义。通过对一个数据中心的典型案例进行CFD研究表明：不同的轮巡备份策略下的机房热环境是不同的,某些轮巡备份方案可能会导致机柜得不到足够的冷量而出现过热,造成设备宕机;对单个机柜而言,由于不同的轮巡策略下获得的冷量不同,其能承载的设备负荷具有可变性。在制定空调的轮巡备份方案时,必须利用CFD对机房环境进行科学的热评估,根据计算结果去探索最佳的轮巡备份策略,从而拟定和执行合理的轮巡备份方案。     

绿色节能机房空调对制冷配件的新需求

本文介绍了数据中心制冷系统的发展趋势,从高可靠性、节能性、高热密度与模块化等几个方面阐述了绿色节能机房空调系统对制冷配件的特殊要求。     

数据中心热管背板空调应用实测研究——机房空气流场分析

介绍用于数据中心的热管背板空调系统的运行原理,通过现场试验,发现背板空调在实际应用时,可能出现机房温度上热下冷,机柜回风温升过高的问题。理论分析及试验验证表明,机柜缝隙密封、机柜内负载均匀布置、背板空调自带风机等方式可有效解决上述问题。     

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%。     

机柜服务器热管背板换热性能的试验研究

通过测试热管背板系统在不同进风温度、制冷剂冷凝单元（RCU）冷冻水进水温度及水流量工况下的换热能力,分析环境温度升高、系统供水不足等对高密度机柜服务器安全运行的影响,采用模拟负载机柜测试机房机柜安装热管背板后不同位置的换热能力。结果表明,热管背板系统对进风温度、冷冻水温度及流量具备良好的换热适应性,发热量大的服务器优先安装在机柜中下部,发热量小的服务器安装在机柜上部,可以最大限度发挥热管背板的换热能力。     

Prozessberechnungen für eine CO<Subscript>2</Subscript>-Anlage zur Kälte- und Wärmeerzeugung für Supermärkte. Teil 2: Begrenzte bzw. keine CO<Subscript>2</Subscript>-Abkühlung durch Umgebungsluft

CO₂ processes are used in supermarkets for medium- and low-temperature refrigeration and by now even for room heating and hot tap-water preparation via heat recovery. Through systematic thermodynamic process calculations, the limits of the heat recovery and it’s influence on the refrigeration process as well as the complete system are investigated for a supermarket with 100 kW medium-temperature refrigeration capacity. This investigation focuses on the energy efficiency of the heat supply by the extended CO₂ plant. By using the medium-temperature refrigeration capacity as reference, the results for ambient temperatures between ??15?°C and +?10?°C are applicable for other supermarket sizes as well.In part 2, a plant is investigated with a ratio between low- and medium-temperature refrigeration capacity of 0.2 and of 0.4, and limited or no CO₂ cooling the ambient air. The contributions of refrigeration and heat supply are specified for a range of high-pressure values for sub-critical and for trans-critical operation of the CO₂ plant. Relevant data for design and operation of the CO₂ plant are made available: the supplied heating capacity (relative to the medium-temperature refrigeration capacity), the coefficients of performance and the exergy efficiencies of refrigeration (medium-temperature, low-temperature and total), of heating, and of combined refrigeration and heating. With this knowledge, optimal operation parameters for the CO₂ process can be chosen depending on the ambient temperature. Moreover, the decision is prepared, whether an additional heating system is required or the heat recovery from the refrigeration plant is sufficient.     

Prozessberechnungen für eine CO<Subscript>2</Subscript>-Anlage zur Kälte- und Wärmeerzeugung für Supermärkte. Teil 1: Weitestgehende CO<Subscript>2</Subscript>-Abkühlung durch Umgebungsluft

CO₂ processes are used in supermarkets for medium- and low-temperature refrigeration and by now even for room heating and hot tap-water preparation via heat recovery. Through systematic thermodynamic process calculations, the limits of the heat recovery from a CO₂ plant and its influence on the refrigeration process as well as the complete system are investigated for a supermarket with 100 kW medium-temperature refrigeration capacity. This investigation focuses on the energy efficiency of the heat supply by the extended CO₂ plant. By using the medium-temperature refrigeration capacity as a reference, the results for ambient temperatures between ??15?°C and?+?10?°C are applicable for other supermarket sizes as well.In part 1, a plant is investigated with a ratio between low- and medium-temperature refrigeration capacity of 0.2 and CO₂ cooling via the ambient air as far as possible. The contributions of refrigeration and heat supply are specified separately for a range of high-pressure values for sub-critical and for trans-critical operation of the CO₂ plant. Relevant data for design and operation of the CO₂ plant are made available: the supplied heating capacity (relative to the medium-temperature refrigeration capacity), the coefficients of performance of refrigeration and of combined refrigeration and heating, and the exergy efficiencies of refrigeration and of combined refrigeration and heating. With this knowledge, preferred operation parameters for the CO₂ process can be chosen depending on the ambient temperature. Moreover, the decision is prepared, whether an additional heating system is required or the heat recovery from the refrigeration plant is sufficient. In the following second part, results for limited CO₂ cooling via ambient air will be considered.     

基于用户体验的适老化橱柜设计

如今人口老龄化呈现加速态势,我国进入老龄化社会。结合老年人特殊的生理和心理需求,研究基于用户体验的适老化橱柜产品的解决方案。首先,通过网上调研和实地调研对市场上已有的适老化橱柜产品进行分类研究,并提出适合老年人使用的厨房布局形式。然后,研究老年人的生理、心理需求及消费观,通过模拟体验、用户访谈等方法进一步研究适老化橱柜创新或改进设计的可能性,以此作为适老化橱柜设计的基石,再基于老年人在厨房工作的痛点,从橱柜外观的形状、材质、色彩和功能的适用性、智能化、交互性等方面提出适老化橱柜产品的设计要素。最后,改进现有适老化橱柜的不足,综合橱柜的智能性与经济性,提出一种新的基于用户体验的适老化橱柜设计方案。     

Modeling and performance analyses of evaporators in frozen-food supermarket display cabinets at low temperatures

This paper presents modeling and experimental analyses of evaporators in “in situ” frozen-food display cabinets at low temperatures in the supermarket industry. Extensive experiments were conducted to measure store and display cabinet relative humidities and temperatures, and pressures, temperatures and mass flow rates of the refrigerant. The mathematical model adopts various empirical correlations of heat transfer coefficients and frost properties in a fin-tube heat exchanger in order to investigate the influence of indoor conditions on the performance of the display cabinets. The model is validated with the experimental data of “in situ” cabinets. The model would be a good guide tool to the design engineers to evaluate the performance of supermarket display cabinet heat exchangers under various store conditions.     

Carbon dioxide as a working fluid in drying heat pumpsLe dioxyde de carbone comme fluide actif dans des séchoirs à pompe à chaleur

Carbon dioxide as a working fluid in refrigeration and heat pump systems is increasingly important in view of the CFC substitution problem. It is both under ecological and economical aspects an attractive alternative to the HFC working fluids at present in practical use. The thermophysical properties and characteristics of carbon dioxide are quite different from those of refrigerants used in conventional vapour compression cycles. Its application in conventional vapour compression refrigerating systems is limited by its critical parameters (t_c=31.1°C and p_c=73.8 bar). The possibility to use carbon dioxide also beyond these limits in high temperature processes, e.g. heat pumps, is given by the application of a trans-critical process. The design and construction of a commercial drying heat pump system (batch type cabinet dryer with 12 kW heating capacity and closed air circuit) using the natural working fluid carbon dioxide is shown and experimental results of investigations carried out are presented. Energy savings are given compared to manufacturer's data of energy consumption.