氯化锂－水吸附式再循环型空调制冷系统性能研究

对氯化锂－水吸附式空调系统在再循环运行方式下的性能进行了模拟。分析了再生温度、热交换器效率及蒸发冷却器效率对性能的影响。与开式通风型空调制冷系统的制冷性能相比，再循环型空调制冷系统的制冷能力较大，但性能系数ＣＯＰ较小     

混合制冷剂循环的级数对制冷性能的影响

混合制冷剂制冷循环可以提高制冷系统的效率,广泛应用在天然气液化领域。混合制冷剂的循环级数对制冷性能影响很大。针对不同级数的混合制冷剂循环进行热力学分析,建立了流程中主要设备的热力学模型,模拟计算了采用不同级数的混合制冷剂循环的天然气液化流程,得到不同级数的制冷循环的主要参数：制冷压缩机的功耗、制冷系数和火用效率。结果表明,制冷循环的级数增加,制冷系统的功耗降低,制冷系数和火用效率增加,但是级数增加对制冷性能的影响减小。制冷循环的级数增加会增加流程的复杂性,降低可操作性,不同规模的制冷系统的最优级数不同,规模越大,最优级数就越多。     

制冷管道泄漏的带压快速粘补

制冷管道泄漏的带压快速粘补韩胜利（安徽剧院动力科，合肥市，２３０００１）在空调制冷系统中有许多管道相连接，当制冷管道存在裂纹，气孔等贯穿性缺陷时，由于制冷剂的渗透性很强，极易从缺陷处渗漏，导致设备制冷量下降或不制冷。我院的空调制冷采用ＦＪＺ－３０Ａ冷...     

吸附式制冷中吸附剂传热传质的强化

对吸附式制冷系统中吸附剂的两种关键性能－有效吸附量及导热系数进行了实验及理论研究。测量了几种吸附剂的上述性能并进行了数据拟合,分析了吸附剂吸附性能及导热系数对吸附制冷系统效率的影响,提出了以吸附制冷最佳经济效率为目标函数的吸附剂性能强化手段,并进行了一些实验研究,取得了较好的效果。     

基于R124/DMAC为工质的压缩吸收式制冷系统的性能分析

吸收式制冷能够利用工业余热进行制冷,但存在不能高效利用100℃以下废热的问题。本文以压缩吸收式制冷系统为研究对象,采用新型制冷工质对R124/DMAC,对不同发生压力、发生温度和冷凝温度下系统性能的变化规律进行研究,并与传统氨/水制冷系统的性能进行比较。结果表明影响系统制冷系数(COP)、?损和?效率的主要因素是发生温度和发生压力,在相同冷凝温度下,R124/DMAC制冷系统的最佳发生压力为600k Pa,最佳发生温度为75℃;而氨/水制冷系统的最佳发生压力为1100k Pa,最佳发生温度为100℃,采用新型制冷工质对能够有效地利用更低品位的热源进行制冷,同时系统的安全性更高。     

双温低品位热驱动新型吸收制冷循环性能

针对传统低品位热驱动CO₂-离子液体制冷系统的制冷效率低等缺陷,从吸收制冷循环基本原理和能量梯级利用原理出发,提出一种双低品位热驱动CO₂-[emim][Tf₂N]吸收制冷系统。为了测试新系统性能,自行搭建双低品位热驱动CO₂-[emim][Tf₂N]吸收制冷实验装置。在定流量的实验条件下进行新系统性能的实验研究。实验结果表明,双低品位热驱动CO₂-[emim][Tf₂N]吸收制冷系统的制冷系数和制冷量随高低温热量比的增大而增大,随高压箱体压力和冷却水入口温度的升高而降低,新系统可制取高品位冷量,还具有较高的效率,制冷效率提高将近50%左右。     

优化控制R744多喷射器双温超市制冷系统

为了使R744双温超市制冷系统在任何环境温度下都能以最高效率运行，在R744平行压缩制冷系统中增加了一个多喷射器组回路（包括气气喷射器和气液喷射器），以确保系统在高温环境下仍能以较高的效率运行。并在环境温度变化的情况下，通过自动控制阀切换多喷射增压制冷模式和平行压缩制冷模式，为此建立了系统的热力学模型。计算结果表明，当环境温度低于17.32℃时，采用平行压缩制冷模式;当环境温度高于17.32℃时，采用多喷射增压制冷模式。当环境温度从21.1℃变化到36℃时，多喷射器制冷系统的COP比平行压缩制冷系统高15.91％~32.61％。     

天津某厂制冷供热站设计

以天津某厂制冷供热站主要设备选型为例,介绍了制冷供热系统设计,并分析比较了制冷机组运行成本,结果表明,蒸汽溴化锂吸收式冷水机组在化工厂空调制冷系统中,利用低品位热能制取冷冻水,可达到节能、降低产品能耗的目的。     

C02充注量对跨临界轿车空调系统性能的影响

试验研究了CO2充注量对跨临界轿车空调系统性能的影响．研究表明：CO2充注量对跨临界制冷系统的性能影响很大，存在一个最佳的CO2充注量，此时COP最大；CO2充注量不足，会导致制冷量和COP降低，COz充注量过多，会导致压缩机耗功大幅度上升；制冷循环随CO2充注量的不同，具有6个特征明显的工作循环．根据这些表现特征，提出了用4个参数作为判断CO2充注量是否合适的特征参数．为确定跨临界制冷系统的最佳充注量、对系统进行优化设计和高效运行控制提供了参考．     

改进型太阳能喷射制冷系统变工况特性

太阳能喷射制冷系统具有变工况间歇性工作特点,为提高太阳能喷射制冷系统的使用时间,获得太阳能喷射制冷系统的最佳变工况工作特性,提出了改进太阳能蓄热水箱流程,并在建立太阳能喷射制冷系统热力学模型基础上,选择新型环保制冷剂R161为工质研究了太阳能喷射制冷系统变工况热力学特性。结果表明,与传统太阳能喷射制冷系统相比,所改进的太阳能蓄热水箱结构增加了太阳能喷射制冷系统工作时间和系统制冷效率,系统工作时间延长12.5%,系统提前2 h开始工作,系统的制冷效率提高8.5%。该研究结果可为改进型太阳能喷射制冷系统的工程设计提供理论参考。     

Cooling of a Diesel Reformate Fuelled Solid Oxide Fuel Cell by Internal Reforming of Methane: A Modelling Study

In this paper a system combining a diesel reformer using catalytic partial oxidation (CPOX) with the Solid Oxide Fuel Cell (SOFC) for Auxiliary Power Unit (APU) applications is modeled with respect to the cooling effect provided by internal reforming of methane in anode gas channel. A model mixture consisting of 80% n-hexadecane and 20% 1-methylnaphthalin is used to simulate the commercial diesel. The modelling consists of several steps. First, equilibrium gas composition at the exit of CPOX reformer is modelled in terms oxygen to carbon (O/C) ratio, fuel utilization ratio and anode gas recirculation. Second, product composition, especially methane content, is determined for the methanation process at the operating temperatures ranging from 500 ℃ to 520 ℃. Finally, the cooling power provided by internal reforming of methane in SOFC fuel channel is calculated for two concepts to increase the methane content of the diesel reformate. The results show that the first concept, operating the diesel reformer at low O/C ratio and/or recirculation ratio, is not realizable due to high probability of coke formation, whereas the second concept, combining a methanation process with CPOX, can provide a significant cooling effect in addition to the conventional cooling concept which needs higher levels of excess air.     

Process analysis of a reactor-separator system: Enzymic degradation of polymeric substrates

The analysis deals with an integrated system in which enzymic de-polymerization of a macromolecular substrate and concomitant separation of the reaction products take place. The enzyme is immobilized within a packed-bed reactor and products are separated by ultrafiltration. A compartmental model was set up and used to simulate the performance of the system in terms of yield, purity, and productivity of the monomer obtained, and as a function of the system operating mode (batch or continuous), recirculation ratio, enzyme mode of action (preferred attack or exo-type), and initial polymer concentration. Results, calculated using the analytical model, are in good agreement with our experimental findings concerning the depolymerization of inulin by exo-inulinase. Future applications include engineering design of the system and optimization of its operational parameters.     

热电制冷模块热连接与电连接的性能优化分析

在考虑汤姆逊效应情形下,分析两块热电制冷模块的热连接与电连接方式的制冷性能,讨论热电偶对数比、工作电流和面长比对4种连接方式的制冷量和制冷系数的影响,探讨4种连接方式的最佳工况和适用范围。发现在大制冷量或较小温差需求下可选择热并联电串联模式;在较大温差需求下可选择热串联模式,且热串联电串联的制冷量始终大于热串联电并联的;然而对于中等温差需求,当需要大的制冷量时,可选用热并联电串联,当需要较高的制冷系数时,可选用热串联电串联。为实际应用中多个制冷模块的连接方式的选取提供了理论指导。     

Residential Solid Oxide Fuel Cell Generator Fuelled by Ethanol: Cell,Stack and System Modelling with a Preliminary Experiment

The flexibility and feasibility of a 5 kW SOFC generator designed for natural gas (NG) and fuelled by a non‐conventional liquid fuel such as ethanol is analysed. A complete generator model is implemented to predict and determine the main criticalities when ethanol fuel is adoperated. The main balance‐of‐plant (BoP) units considered are the reformer, the recirculation system based on an ejector, the tubular cells bundles constituting the stack unit, the after‐burner zone and the air blower. The electrical and global efficiencies achieved at nominal operating conditions show how ethanol maintains generator performance good, while only slightly reducing the system AC efficiency from 48% (achieved by NG) to 45%. The effectiveness and flexibility of the recirculation system when changing the fuel is also verified since a safe steam‐to‐carbon ratio (STCR) is established after the fuel is switched from NG ethanol. The stack thermal management is analysed in detail and related to the system performances, showing how a high endothermic fuel reforming reaction is required to maintain the overall system efficiency. A preliminary experiment with ethanol feeding the Siemens generator is finally presented. The system response to the new fuel is monitored by several measured parameters and the system regulation is explained.     

中央空调循环水系统的不停车清洗及水处理技术

介绍了中央空调系统敞开循环水系统不停车清洗的研究成果及应用结果。通过大量的试验研究,研制出适用于中央空调系统敞开循环水系统不停车清洗的专用复合清洗剂HS-906。根据中央空调系统的运行特点,确定了清洗工艺。应用结果表明该清洗剂及清洗技术,清洗效果明显,具有对中央空调系统的铜管、钢管、水塔及填料腐蚀性小等特点。     

热驱动的双模式冷电联供系统的性能分析

有机朗肯循环（ORC）与吸附式制冷结合的冷电联供系统可实现对低品位热能较好的回收利用。针对应用中存在有/无须制冷情况,提出了一种热驱动的双模式ORC-吸附式冷电联供系统,并建立数学模型进行性能对比分析。冷电联供时,ORC和吸附式系统分别输出电和冷;电力单供时,吸附式系统制出的冷水直接用于冷却ORC系统冷却器,获得更大的电输出。数值计算结果表明,与单一ORC系统、单一吸附式系统和传统单模式ORC-吸附式冷电联供系统相比,双模式ORC-吸附式冷电联供系统在可获得更佳的性能,且在高热水温度条件下,性能优势更加明显。     

3万t/a钾碱制片机的设计、制造与应用效果

阐述了3万t/a钾碱制片机的工作原理,即实质上是一个用于连续冷却制片的旋转的冷却机器;并从转鼓的选材、结构,冷却系统及刀架机构等方面介绍了其设计、制造方案;从性能与结构上与原1万t/a制片机进行了比较,并介绍了在成都华融化工有限公司运行1年后的应用效果.     

Electrochemical hydrogen pump for recirculation of hydrogen in a fuel cell stack

The objective of this work is to evaluate the use of an electrochemical hydrogen pump for recirculation of hydrogen in a fuel cell stack. The hydrogen pump needed about 130 mV at 0.5 A cm⁻², primarily because of the cell resistance (0.18 Ω cm²). This voltage loss was higher than a fuel cell voltage gain resulting from hydrogen recirculation. However, if one pumping cell is used for 10 active cells this means 13 mV loss per cell (or about 2%) which may be an acceptable voltage penalty. A stack with hydrogen recirculation should operate with less voltage fluctuation and should need purging less often than a stack operating with a dead-end mode of hydrogen supply. An additional benefit of hydrogen purification may be achieved in the systems with a fuel processor where operation in a dead-end mode is not possible. Attention must be paid to water management when designing and operating a hydrogen pump within a fuel cell stack.     

新型光伏直膨式太阳能/空气能多能互补热泵性能

以平板热管（微热管阵列）为核心部件，设计了一种新型太阳能光伏/空气集热蒸发器并建立了光伏直膨式太阳能/空气能多能互补热泵系统，实现全年供热水、冬季供热、夏季供冷以及全年光伏发电的功能。对北京地区3月至5月天气条件下的热泵系统性能进行不同运行模式（S、SA以及A模式）的实验研究。实验结果表明，在典型工况下S、SA与A模式的多能互补系统COP_s分别为4.8、4.2与3.8，综合效率分别为109.7%、125.9%、32.4%，即在有太阳辐照的条件下，S与SA模式下多能互补系统性能优于A模式。该新型光伏直膨式太阳能/空气能多能互补热泵系统性能优良，研究结果为该系统应用提供了基础数据支撑。