对相变降温服的相变材料充注量及摆放位置的研究

为了研究相变降温服中相变材料的充注量及其摆放位置,该文提出了一种新型的空气式相变降温服方案。通过建立热舒适模型对相变材料的质量进行了理论计算,并设置不同的材料摆放方案,模拟夏季高温环境对相变降温服的效果进行了实验。结果显示,真人穿着相变降温服时人体表面平均温度比未穿着相变降温服时降低3℃,由此该文所提出的相变降温服方案可以有效降低人员的皮肤温度。     

环形相变单元的蓄热装置设计及运行特性

通过对圆柱和圆环相变单元进行蓄放热性能实验,发现环形结构可有效降低蓄放热时间,提高相变材料蓄放热速率。采用环形相变蓄热单元,设计了一种新型相变蓄热装置,搭建了相变蓄热实验系统,对蓄热装置运行特性进行了分析。结果表明:蓄热工况下,增加换热流体流量,提高换热流体温度,可明显提高蓄热速率;放热工况下,增加换热流体流量可加快蓄热装置的热释放速率,但流量过大相变潜热无法及时释放,在冷水补水流量为4 L/min时,可多提供约44 L温度高于40℃的热水。根据实际生活用水,对间隔用水分别为5 min和10 min两种工况进行了放热实验,同样可以满足用水需求。     

变形方式对含ZrC粒子20Mn2钢晶粒细化的影响

研究了恒温压缩与降温轧制对含ZrC粒子20Mn2钢晶粒细化的影响.结果表明,在奥氏体再结晶温度区间(1150℃、1050℃)和形变诱导铁素体相变温度区间(950℃、900℃、870℃、850℃),20Mn2钢的晶粒尺寸均能细化至3～4μm;在1150～870℃的降温轧制中,20Mn2钢的晶粒尺寸细化至1～3μm.分析表明,由于ZrC粒子的形变核心和再结晶核心的作用,含ZrC粒子的20Mn2钢在高温下(1150℃、1050℃)和较低温度下(950℃、900℃、870℃、850℃),变形的晶粒组织分别因奥氏体再结晶和形变诱导铁素体相变及其再结晶而得到细化;在降温轧制时,由于综合了高温奥氏体再结晶和低温形变诱导铁素体相变及其再结晶的细化晶粒效应,而最终获得的晶粒尺寸比恒温变形的更小.     

微正压柔性精准送风方式对特定区域的空气调节的实验研究

夏季高温严重影响特殊需求房间的热舒适性,本文提出一种新型微正压柔性精准送风系统,以纤维风管定点送风,将冷风输送至热活动区域进行局部降温实验,研究喷口尺寸、风速、送风温度等参数对局部降温效果的影响,寻找最佳的送风方案。实验结果表明:室外日平均温度为35.4℃,空气相对湿度为60%时,送风温度13℃和孔口风速9m/s进行送风时,到达指定位置风速为1m/s效果最优,且室内平均温度维持在21.5℃;在极端天气室外温度高达40℃,建议以送风温度13℃送风,室内平均温度可维持在24℃,依然可以满足制冷要求。     

应用于电池热管理的均温板的温度特性研究

本文以一款内部具有流道以及相变工质R1233zd的均温板为研究对象,将均温板置于冷源与热源之间,对其温度场进行了理论分析和仿真模拟,并通过搭建实验台,对均温板的温度特性进行了实验研究。实验结果表明:均温板表面温度分布与冷源表面温度分布具有良好的一致性。均温板表面温度分布受热源功率和冷源温度的影响:当热源功率由345 W升至690 W,而冷源温度保持0℃不变时,均温板表面平均温度由13. 20℃升至25. 84℃,表面温差由11. 10℃升至25. 70℃;当冷源温度由0℃降为-5℃,而热源功率保持690 W不变时,均温板表面平均温度由25. 84℃降至18. 15℃,表面温差由25. 70℃降至16. 60℃。在不同工况下,均温板热阻约为0. 03 K/W,具有良好的导热性能。     

成都地区相变墙体夏季工况的参数优化及效果分析

为了解相变墙体传热特点和评价相变材料在成都地区的使用效果,建立相变墙体传热数理模型并通过实验验证模型正确性。在此基础上分析了成都地区夏季工况下相变材料的相变温度、相变区间、相变潜热和导热系数对使用效果的影响,并对参数进行优化。结果表明:适合成都地区夏季墙体内表面的相变材料的相变温度为25～26℃,相变区间为2℃以内,相变潜热与使用效果呈线性关系,导热系数对使用效果影响不大。     

冷凝排热-相变蓄热热回收空调系统的实验研究

利用相变蓄热材料的相变过程将空调系统冷凝热回收并制取热水，解决空调系统运行时段与热水使用时段的时间差以及生活热水的用量与冷凝热量之间的不一致。针对冷凝排热相变蓄热热回收空调系统制备生活热水进行试验研究。实验结果表明，通过选择合适的相变蓄热材料，该系统试验工况下制取的热水达到了预期温度35～40℃，可满足洗浴用生活热水的温度要求；如需更高温度的热水，可在热水管路上设置辅助加热器加热，以满足要求。     

聚乙二醇对沥青及其混合料储热性能的影响

利用相变材料物相转变时吸收或释放大量热量而本身温度保持不变的特性,将相变材料聚乙二醇应用于沥青及沥青混合料中。考察了聚乙二醇对沥青性质、相变沥青混合料降温性能和高温稳定性的影响。结果表明,聚乙二醇的掺入可降低沥青的温度敏感性,制备的相变沥青与石灰质的集料粘附性良好;相变沥青混合料具有良好的储热能力,掺量为15%和20%时,相变沥青混合料在自然光照条件下的能主动降温1.3℃和1.4℃,其高温稳定性能满足当前规范要求。此外,通过红外光谱分析得出聚乙二醇与沥青的相互作用形式仅仅是物理共混。     

西安市某大型商场喷淋屋顶天窗的降温效果分析

选取西安市大型商场的屋顶喷淋玻璃天窗、对照玻璃天窗和对照平屋顶为研究对象,测试了在高温夏季天窗外表面的温度,对比分析了屋顶天窗喷淋后的降温效果。数据显示,与对照屋顶天窗相比,喷淋天窗的降温程度范围为3℃~5.7℃,平均降低天窗温度3.86℃,降温率变化范围为7.58%~12.72%,降温率平均达到9.23%。同时SPSS独立样本T检验得到,两者温度差异显著,95%的区间估计两者的温度之差约为[1.1,7.5];与平屋顶相比,喷淋天窗的降温程度变化范围为11.6℃~17.5℃,屋顶平均温度降低了13.09℃。降温率变化范围为25.16%-30.92%,平均降温率达到27.58%。同时SPSS的方差分析及F检验显示,与两对照组相比,喷淋天窗均有显著的降温效果。     

果蔬用敞开式陈列柜温湿度场分布特性实验

为研究带单层风幕的敞开式果蔬陈列柜温湿度分布规律,采用了一种立式敞开式陈列柜试验平台作为研究对象,分析陈列柜稳态运行阶段回温、降温和节能帘对温湿度场分布特性的影响。试验结果表明: 在无节能帘条件下,回温工况结束时温湿度场比降温工况均匀,其温度、相对湿度分布的变异系数分别为0.25、0.08。陈列柜左部温度和相对湿度均低于右部;4层搁架温度、相对湿度分布差异显著（P<0.05）。稳态运行阶段,搁架温度和相对湿度分布呈周期性振荡,周期约为17min;运用线性回归方法建立各测点相对湿度关于温度的函数模型,回归方程表明：相对湿度与温度呈线性正相关;与无节能帘时相比,节能帘条件下的柜内平均相对湿度高5.74%RH,平均温度低0.43℃,温度、相对湿度的波动幅度小,降温时间短和回温时间长。研究结果为果蔬用敞开式陈列柜性能的优化提供参考。     

基于体表温度的着封闭服装青年群体行走时核心体温研究

目的 针对诸如消防员等着封闭/密闭服装工作时人的生命安全监控一直是此类行业关注的一个重点,人的体核温度与人的体能状态及生命安全密切相关.本研究旨在探究人体在舒适及高温高湿条件下着封闭服装行走时生命体征的安全阈值、耐受阈值以及体表温度与体核温度的相关性.方法 选择16名某部士兵作为志愿者,让其穿着防护服(封闭),设定的试...     

Characterization of UME-Made Co–C Eutectic Fixed-Point Blackbody Cells

Eutectic phase transitions are commonly considered for use as fixed points in future 20XX temperature scales. Despite their potential as possible interpolation points in a high-temperature radiation thermometry scale (1000 °C and above), more studies on the reproducibility of the plateau temperature values are required. Various ongoing research projects on the long-term stability and reproducibility of the eutectic fixed points will likely improve the uncertainties enough to allow for their use as reference (or secondary) temperature points. In this article, the long-term reproducibility results of Co–C eutectic plateau realizations performed in the UME Radiation Thermometry Laboratory over four years, along with studies of the dependence on furnace heating/cooling rate and the short-term (1 day) repeatability, are presented. These measurements were performed with a monochromatic radiation thermometer calibrated according to ITS-90.     

一种变频空调电控箱体降温模块的研究

本文根据变频热泵机组系统特点和制冷循环热传导原理设计了一种变频空调电控箱体的降温模块,该降温模块的U型散热装置与制冷剂配管接触弧度为3/4圆弧结构,接触点切线成45°斜角,放置在空调系统中出储液器到进入电子膨胀阀之间的管路部分,使制冷剂经过该散热装置的温度处于40℃～50℃之间最佳温度范围。在环境温度43℃、出水温度15℃的制冷工况下,通过实验分析和验证了增加该散热装置和自然冷却两种状态下系统的性能。结果表明:加装制冷剂散热装置机组运行时变频器功率器件产生的热量可以通过制冷剂散热装置带走,降温效果较为明显。同时,通过理论计算和实验测试对比了变频器功率发热部件温度与制冷剂进口温度之间温度差变化情况,验证了加装制冷剂散热装置的效果。     

考虑实际压缩效率的NH3/CO2复叠制冷系统热力学分析

为优化复叠制冷系统的运行参数,本文对NH3/CO2复叠制冷系统进行了热力学分析,搭建了NH3/CO2复叠制冷系统实验台,获得了部分工况点的实验数据,并与采用不同压缩机等熵效率经验公式的热力学分析结果进行对比及误差分析,最终采用与实验数据相吻合的压缩机等熵效率经验公式,对系统的最大性能系数、最佳中间温度及最优级间容量比随...     

多联式热泵驱动热管复合供热装置的实验研究

本文提出多联式热泵驱动热管的新型供热循环方式。该方式的特征是采用空气源热泵直接驱动串联式热管散热器供热。为验证该供热方式可行性,本文基于额定功率为2.5 k W的压缩机和9台热管散热器搭建了实验台,在不同工况下进行测试。测试结果表明:新型供热装置启动速度较快,当室外温度为-10℃时,系统运行36 min时,热管散热器表面温度即可达到45℃。热管散热器温度均匀性好,除1#、9#散热器存在过冷、过热现象外,其余散热器之间温差约为1℃。同时系统传热温差小,并能在除霜工况下正常运行。     

夏季冷热联供模式下的燃气机热泵机组性能分析

本文建立了一套以R134a为制冷剂工质、以天然气为一次能源驱动开启式压缩机做功的燃气机热泵系统,研究了当蒸发器进水温度为12～22℃,室外环境温度为24.2～35.6℃,发动机转速为1 400～2 000 r/min,夏季冷热联供模式时,空气源燃气机热泵(GEHP)机组的性能。结果表明:发动机转速和蒸发器进水温度的变化对系统性能的影响大于室外环境温度变化的影响。随着发动机转速由1 400 r/min增至2 000 r/min,系统COP_1、COP_2、PER_1、PER_2分别减小了15.5%、9.9%、18.8%、13.5%。在工况范围内,机组冷水出水温度可达6.7～19.3℃,热水出水温度可达40.7～61.7℃,考虑余热回收情况下系统PER_2可达1.14～1.45。     

Subjectively assessed age-related stress and strain associated with working in the cold

In the context of an age-differentiated workforce employment, two age groups out of 128 males and females who were employed in 24 deep cold-storage depots have been interrogated in order to identify their subjective experiences of working in the cold. In this study, 63 employees below the age of 35 and 65 employees above the age of 35 years represented the group of ‘Younger Subjects’ and ‘Older Subjects’. While order-picking groceries all Subjects (Ss) are exposed to environmental temperatures of approximately +3°C in a chill room and to ?24°C in a cold store. By means of a standardised questionnaire, subjective experiences about, e.g. the physical strain, the current regulation of working time and warming-up breaks, the environmental conditions and the cold protective clothing were collected and analysed. In most cases, age-specific differences could not be detected. While the working environment was assessed quite similarly by younger and older Ss, the regulation of working time and warming-up breaks and the cold protective clothing were rated rather differently. With more often occurring and sometimes stronger cold sensations of the younger Ss, substantial differences between the two age groups could be detected.     

Experimental investigation of solar driven desiccant air conditioning system based on silica gel coated heat exchanger

A silica gel coated heat exchanger based air conditioning system driven by the evacuated tube solar water heater has been experimentally investigated. The system has been operated for two different modes namely cooling with dehumidification mode and heating with humidification mode in summer and winter season respectively. The system performance is analyzed in terms of regeneration rate, dehumidification rate and thermal coefficient of performance (COP_th). Experimental results demonstrated that, for cooling and dehumidification mode, the process air is cooled by an average temperature of 8.5 °C. A better dehumidification rate can be achieved by using pre-cooling before dehumidification process. Post-cooling after dehumidification process is found to be advantageous for cooling capacity and COP_th. For heating with humidification mode, the process air is heated by an average temperature of 13.3 °C with an average increment in humidity ratio of 1.9 g/kg. It is found that the average COP_th of the system is 0.45 and 0.87 for cooling and heating mode respectively.     

Experience of Construction and Study of Pt–C Eutectic in VNIIM and Cooperation with LNE-INM

A new high-temperature furnace was developed in VNIIM and manufactured by the Omsk plant “Etalon.” This furnace is intended for the realization of various fixed points of pure metals and high-temperature metal–carbon eutectics up to a temperature of 3000°C. The construction of the furnace allows measurements to be carried out either with or without the protective window, in a protective atmosphere of argon. The furnace will be described in this article. Cooperation with LNE-INM was initiated with the aim of sharing experience in metal–carbon eutectic cell construction and comparing two Pt–C cells (one cell was made by each partner) as a means of comparing scale realizations around 1740°C. The filling technique used in each laboratory will be described. The average melting temperature of the VNIIM Pt–C eutectic cell, characterized and studied at VNIIM, was 1738.4°C with a standard uncertainty of about 0.13 K. The repeatability of the melting temperature with various measurements was estimated to be within the limits of (0.02–0.2) K. The cell supplied by LNE-INM is the one that was constructed and studied in the framework of the HIMERT European project and described elsewhere. The difference in the melting temperatures of the fixed points (VNIIM—LNE-INM) is about 0.4 K with a standard uncertainty not exceeding 0.18 K. The cells constructed and characterized by each partner were exchanged and measured by the other partner. The results of the study of the melting and freezing of the Pt–C cells carried out by VNIIM and LNE-INM will be presented. The reasons for the difference in the melting temperatures of the two cells are analyzed, and the steps preceding the comparison of the scale realizations of the two laboratories are presented.     

热环境下人体穿着热湿舒适性研究

研究不同环境温度和环境湿度条件下,人体穿着不同服装时出汗量、皮肤温度、衣内温湿度、主观感觉等人体生理指标的变化。结果表明：①环境温度和环境相对湿度变化,所测得的各生理指标都发生显著变化,表明环境因素对人体热湿舒适性有很大影响;②热环境下具有良好的透湿透气性能的现行制式陆军夏服表现出良好的热湿舒适性能,而纯棉服装的热湿舒适性较差,尤其是在高温高湿条件下穿着时。因此对于夏季服装,透湿透气性好的服装穿着最为舒适。