浅谈医院洁净手术室空调设计

概略指出洁净手术室空调系统设计中在压力、温湿度控制,新风过滤器、回风口、加湿器设置等方面存在的常见问题,给出了基本满足《医院洁净手术部建筑技术规范》（2000年送审稿）的洁净空调系统的示意图。     

低温干燥冷藏调湿多功能储粮系统及特性分析

干燥是粮食行业的主要耗能环节,目前粮食干燥多采用烘干机或烘干塔,热损失大、能耗高,有些以煤炭作为热源,环境污染严重。另外,粮食长期储藏过程中易发生霉变和虫害,同时长期储藏会导致粮食水分过低影响粮食加工品质。实现粮食高品质、低能耗干燥及长期安全储藏和保证出库粮食的品质具有重大意义,因此提出了一种低温干燥冷藏调湿多功能储粮系统,并基于该系统开发了具有低温干燥模式、低温冷藏模式和加湿调质模式的设备,可实现“一站式”储粮,使储粮全程自动化控制。通过实验测试,结果表明,三种工作模式下,机组出风参数均满足设计要求。对玉米和萝卜进行了初步干燥实验,玉米的平均干燥速度约1.1%/h、萝卜干燥平均干燥速度2.9%/h左右。通过对系统进行能耗分析可知,本机组与烘干机相比可节能19.4%左右,与冷凝去湿干燥机相比可节能51.7%左右。该设备的驱动能源为电能,环境友好,便于实现粮库的智能化建设,市场应用前景广阔。     

4种常见果蔬保鲜运输超声波加湿的生命周期模拟研究

通过生命周期评估显示:与传统供应链相比,超声波加湿可将部分水果和蔬菜的环境影响(包括气候变化影响)降低23%,当加湿器应用于果蔬供应链,且总固有损失>24%时,加湿器的加入能使损失减少20%以上,说明超声波加湿技术能使果蔬供应链管理更具可持续性。     

Quasi-stationary UI-characteristic model of a PEM fuel cell–Evaluating the option of self-humidifying operation

This work presents a zero-dimensional PEM fuel cell UI-characteristic model created in MATLAB Simulink® for operation with dry or humidified air supply. It is parameterised and validated based on the results of stack operation by varying stack temperature (50–80 °C), gas pressure (1.0–2.4 bar) and air humidification (0.0–1.0). The model is based on physical and electrochemical correlations and expanded by empirically assumptions concerning the influence of the humidification and limiting current density on the performance. The UI-model is intended to be integrated into a comprehensive zero-emission powertrain model. Since non-humidified operation of PEM fuel cell systems provides benefits for mobile applications by reducing space demand and system complexity, the objective of the model is to relate performance to the operating conditions and underlying physical parameters. Results confirm the feasibility of a self-humidifying stack operation at high performance by optimal parameter setting.     

环流反应器的增湿性能与气液传质特性

为研究环流反应器对干空气的增湿效果,分别测量了不同液位和气速条件下环流反应器的进出口气体湿度值,比较了进出口气体湿度变化和增湿效果.并在低液位条件下建立了水分传递的传质模型,推导出传质系数的计算公式.研究表明,在空气和自来水体系的环流反应器实验中,气体增湿效果显著,证明了采用干空气增湿方法浓缩母液的工艺可能性.但由于实验中采用的环流反应器内径小、气速低,单位时间内干空气带走的水分有限,为提高母液浓缩效率可采用降低反应器高度、增大反应器横向尺寸和气速等措施.     

隔膜碱蒸发工艺改进的探讨

天津化工厂为满足10万t／a隔膜烧碱的生产能力，对原双效六体自然循环蒸发工艺进行了改造。改造后的蒸发采用了三效顺流部分强制循环工艺。控制系统采用恒河DCS，调节阀采用模拟量调节阀，进科、过碱、循环全都实现连续进行。离心机采用推科式离心机与卧式刮刀离心机共存的分离工艺。改造中增加了生蒸汽、二次蒸汽去过热增湿系统，使过热度保持在2℃以内，提高各效的传热效率，改造后生产装置汽耗显著下降。     

Mass Diffusion in a Hydrophobic Membrane Humidification/Dehumidification Process: the Effects of Membrane Characteristics

Abstract

Humidification and dehumidification are common processes in air conditioning industry. In this study, a new technique‐the hydrophobic membrane based air humidification and dehumidification are investigated. The effects of membrane characteristics on moisture exchange effectiveness of the system are studied. A two‐dimensional transient model which takes into account the combined mechanisms of Knudsen flow and ordinary diffusion in membrane pores is proposed and validated. Four membranes, 2 hydrophobic treated Nylon and 2 PVDF, are used in the test to validate the model. Then the effects of variations of membrane properties on the system performance and membrane to total resistance ratio, are evaluated. A dimensionless Number of Transfer Units (NTU) can be summarized to govern the moisture exchange performance. Following, a correlation has been obtained to reflect the relations between the moisture exchange effectiveness and the Number of Transfer Units.     

某电子厂含浸车间空调系统改造方案分析

根据改造项目实际情况,分析某电子厂含浸车间冬季空调系统改造项目的空气处理过程.并对两种方案的节能效果进行分析比较.     

Experimental and theoretical study of an integrated thermoelectric–photovoltaic system for air dehumidification and fresh water production

The main objective of this study is to present an integrated thermoelectric–photovoltaic renewable system to dehumidify air and produce fresh water. The system is combined with a solar distiller humidifying ambient air to enhance distillate output to meet the specified fresh water needs for a residential application. A model is developed to simulate the air dehumidification process using thermoelectrically cooled TEC channels. Experiments were performed to validate the developed model results. It is found that the model predicted well the variation in the air temperature along the channel with a maximum relative error in air temperature less than 2.4%. In addition, the simulation model predicted well the amount of water condensate produced by the integrated system with a maximum relative error of 8.3%. An optimization problem is formulated to design and set the integrated system optimal operation to produce 10 L of fresh water per day meeting the fresh water needs of a typical residential. Using five TEC channels of a length of 1.2 m and an area of 0.07 × .05 m² integrated with 1.2‐m² solar distiller that recirculates a constant air mass flow rate of 0.15 kg s^?1 is capable of meeting water demand when air mass flow rate through each TEC channel is optimally set at 0.0155 kg s^?1. The associated optimal electrical current input to the TEC modules varied depending on the month and is set at 2.2 A in June, 2.1 A in July and 2.0 A in August, September and October. Copyright © 2011 John Wiley & Sons, Ltd.     

Coolant induced variable temperature flow field for improved performance of proton exchange membrane fuel cells

The objective of the coolant induced variable temperature flow field concept is to maintain high membrane water content along the entire flow field without external humidification and without occurrence of liquid water inside the cell at higher currents. This is achieved by imposing a temperature gradient in the cathode downstream direction in such manner that the product water is just sufficient to maintain close to 100% relative humidity along the entire flow field. The concept must be feasible for stack applications and flexible to enable efficient operation under significantly different operating conditions. The concept is investigated via interactive combination of computational fluid dynamics modeling and experimental validation for two membranes, namely Nafion^® 212 and Nafion^® 115. Additional calculations are also carried out for a five-cell stack with Nafion^® 212 membranes. The results of the computational fluid dynamics model are compared with the experimental data. Calculated and measured current density and relative humidity distributions along the cell give insight in the membrane water content and membrane water flux. With the coolant induced variable temperature flow field concept it is possible to achieve close to 100% relative humidity along the entire flow field without the requirement for external humidification, and to minimize the occurrence of liquid water inside the cell, resulting in improved performance of the cell in comparison with commonly used isothermal operation.