Thermal seawater desalination based on self-heat recuperation

Recently a novel self-heat recuperation (SHR) technology has been developed for energy saving. In the SHR process, both sensible heat and latent heat are circulated by compression work. Energy consumption is thereby drastically reduced. Using this technology, a new thermal desalination process is developed for reducing energy consumption. The energy required for this SHR-based process is explained by process simulation. It requires ~1/4 the energy of the conventional multi-stage flash desalination process, which is the most widely used thermal desalination. Thus, the proposed thermal desalination process is promising for application in industrial plants.     

集中再生式除湿空调系统

传统空调系统是通过降温的方法来提供房间冷负荷。夏季空调过程分析表明，如果将冷负荷中的热、湿负荷分开处理，不仅可以有效降低制冷机的能耗，还可消除冷却器盘管表面的冷凝水带来的污染，从而提高室内的空气品质。基于以上理论分析，本文就利用天然气等清洁能源或太阳能等低品位热源实现除湿剂再生的固体、液体除湿空调系统的原理及过程进行了介绍。     

Integration of solar thermal energy into processes with heat demand

An integration of solar thermal energy can reduce the utility cost and the environmental impact. A proper integration of solar thermal energy is required in order to achieve it. The objective of this study is to maximise the solar thermal energy delivered to the process. It is a result of trade-off between the captured solar thermal energy and maximal energy delivered to the process (process demand). Two novel curves are introduced to present this trade-off: (i) The Captured Solar Energy Curve (CSEC), which represents the available amount of heat from solar source and (ii) The Minimal Capture Temperature Curve (MCTC), indicating the minimal temperature making the heat transfer feasible. The crossing point of these two curves presents the minimal temperature of the capture being still sufficiently high to be usable for processes. The suitability of these curves for using in combination with standard heat integration methods is analysed and evaluated. The capture potential is revealed in full when the CSEC and MCTC are used with the Grand Composite Curve. In Total Site Profiles, the heat recovery is first maximised and then the CSEC and MCTC tool is applied. The implementation of CSEC and MCTC approach is illustrated by two case studies.     

Aktive Thermosonde zur Messung des Energieeinstromes

A active thermal probe for the measurement of the energy influx A continuously working active thermal probe for the determination of the energy influx at plasma‐technological processes is presented. The principle of mesurement is based on the compensation of the incoming energy influx. Key benefits are the application for continuous measurement and the suitability for thin film deposition. A calibration is not needed. At selected positions of the reactor the energy influx to the probe can be measured and the correlation with properties of the growing layer or the treated surface, respectively, can be determined. Since the thermal probe reacts sensitively to the process parameters at the substrate surface it is very well qualified for control and monitoring of layer growth or surface treatment processes. The probe is a ost‐efficient, particularly suitable device for quality control in plasma‐technological applications.     

热冲击作用下的陶瓷材料破裂过程数值分析

运用热传导和热2力耦合的相关理论 , 借助统计分布来考虑陶瓷中存在的微孔洞和微裂隙 ; 建立了一种可以模拟陶瓷遭受热冲击作用下的裂纹萌生、 扩展过程的数值模拟方法 , 并通过材料破坏过程分析系统 (RF2PA , Realistic Failure Process Analysis) 加以实施。该数值方法基于细观非均匀性假设 , 突破了以往连续介质力学视陶瓷为均匀介质的假设 , 并从细观损伤角度考虑陶瓷热冲击破坏演化的过程。运用该方法对三面绝热、 一面受热冲击的平板状陶瓷材料的破裂过程进行了数值试验。结果表明 : 起始裂纹发端于受热冲击表面 , 且在初始的裂纹萌生阶段 , 在受热冲击表面产生一系列无序的裂纹 ; 但随着时间的延续 , 裂纹逐渐演变成多条近乎平行的、沿受冲击表面内法向方向扩展的主裂纹 , 其中一些裂纹的发展受到了屏蔽 , 这一结果与试验结果吻合较好。本数值方法为相关研究提供了新的思路。      

柔性热电发电器的关键工艺及其展望

热电发电器是固态能量收集器,以可靠和可再生的方式将热能转换成电能。过去几年的研究表明,人体的热量可以很好地被柔性热电发电器转换为电能并加以利用。与用于可穿戴设备的其他传统发电器相比,柔性热电发电器可利用低品位的热能发电且环境友好。柔性热电发电器将有可能为任何无线传感器节点提供足够的能量(通常功率要求小于毫瓦级)。本文综述了热电发电器的概况,重点介绍了制造柔性热电发电器的关键工艺,讨论了热电发电器的基本原理、效率、应用以及存在的一些问题。     

Numerical simulation of an advanced energy storage system using H2O–LiBr as working fluid, Part 1: System design and modeling

The advanced energy storage technology proposed and patented by authors can be applied for cooling, heating, dehumidifying, combined cooling and heating, and so on. It is also called the variable mass energy transformation and storage (VMETS) technology in which the masses in one or two storage tanks change continuously during the energy charging and discharging processes. This paper presents an advanced energy storage system using aqueous lithium bromide (H₂O–LiBr) as working fluid. As one of VMETS systems, this system is a closed system using two storage tanks. It is used to shift electrical load and store energy for cooling, heating or combined cooling and heating. It is environmental friendly because the water is used as refrigerant in the system. Its working principle and process of energy transformation and storage are totally different from those of the traditional thermal energy storage (TES) systems. The electric energy in off-peak time is mostly transformed into the chemical potential of the working fluid and stored in the system firstly. And then the potential is transformed into cold or heat energy by absorption refrigeration or heat pump mode when the consumers need the cold or heat energy. The key to the system is to regulate the chemical potential by controlling the absorbent (LiBr) mass fraction or concentration in the working fluid with respect to time. As a result, by using a solution storage tank and a water storage tank, the energy transformation and storage can be carried out at the desirable time to shift electric load efficiently. Since the concentration of the working solution in the VMETS cycle varies continuously, the working process of the VMETS system is dynamic. As the first part of our study, the working principle and flow of the VMETS system were introduced first, and then the system dynamic models were developed. To investigate the system characteristics and performances under full-storage and partial-storage strategies, the numerical simulation will be performed in the subsequent paper. The simulation results will be very helpful for guiding the actual system and device design.     

Thermal buckling of bimodular sandwich beams

This paper presents a model that explores the thermal buckling of three-layer sandwich beams possessing thick facings and moderately stiff cores. Bimodular facings and core material are used. In contrast to conventional theory, the effects of transverse shear deformation in the facings as well as the effect of the stretching and bending action in the core on thermal buckling are considered. The governing equations are derived using the principle of minimum total potential energy and the fact that its second derivative is zero. The finite-element results are presented in order to investigate the effects of important parameters such as thickness, thermal expansion coefficients and moduli ratio on critical buckling temperatures.     

A generalized variational model of magneto-thermo- elasticity for nonlinearly magnetized ferroelastic bodies

Based on a generalized variational principle of total energy functional, this paper presents a theoretical model to describe the magneto-thermo-elastic interaction of soft ferroelastic bodies with nonlinear magnetization under stationary thermal and magnetic fields. The energy functional of the magneto-thermo-elastic system is established by the summation of energy of sub-systems of nonlinearly magnetized magnetic field, thermal field, and mechanical deformation. By means of the manipulation of the mixed variational principle with independent variations of magnetic scalar potential, displacement vector, and temperature, all governing equations, which are nonlinear and coupling among magnetic, elastic and thermal fields, together with the expressions of magnetic forces are obtained from the variational approach. In order to valuate the obtained model, some existing models of the magneto-elasticity and the thermo-elasticity, which are validly demonstrated in literature, as special cases of the problem considered here are deduced out from the general case. Finally, an analytical analysis of magneto-thermo-elastic instability is conducted to a simply supported ferromagnetic rectangular thin plate under both a uniform distribution of temperature and a uniform transverse magnetic field by means of the linearized theory and the perturbation technique.     

Energierückgewinnung bei der Konvektionstrocknung mit Hilfe von Membranen

Thermal drying of solid materials is one of the most energy-intensive process steps as, in most cases, the recuperation of the high latent heat in water vapour is either not possible or uneconomical. Particularly in convective drying processes, in which hot gases are used as heat carriers, the level of energy in the vapours leaving the dryer is very low. One starting point for significant recuperation of energy is the development of efficient membranes with which it is possible to selectively separate water vapour from exhaust gas or air. After separation, the water vapour can be recirculated – using the principle of mechanical vapour recompression – as hot steam into the drying process. The feasibility of this process can be demonstrated in a laboratory unit. It is possible, by using this process, to reduce the energy used for convection drying to about 25% of the usual requirement. As far as the use of primary energy is concerned, up to 50% can be saved by using a gas motor for the compressor and utilizing the heat produced in the drying process.     

能源计量和建模技术的研究与应用

应用动态多参数在线能源计量技术对企业范围内各用能部门的实时能耗数据进行了准确、稳定、实时的采集和存储,形成了巨量的能源数据库。依据物质平衡和能量守恒原理,运用能耗基准因数法和e-p分析方法,建立了企业生产和能量转换过程的数学模型;评估和计算了设备和工序能耗、产品能值和单位能耗;建立了单位综合能耗模型。该模型成功地应用到北京某啤酒集团的能源计量系统中,通过设备和工序能耗的分析对比,指导工艺优化和节能空间的评估,对工艺和设备能耗进行合理预测。     

Numerical analysis on the heat and work transfer due to shear in a hot cascade Ranque–Hilsch vortex tube

Cascading of vortex tubes is a possible implementation to extract significantly larger amount of useful work. A hot cascade-type RHVT makes use of the cold gas for cooling purposes while improving the heating capacity of the hot gas. In a vortex tube inflow pressure is the only source of energy which converts into thermal energy. The conversion of pressure energy into thermal energy is associated with the heat and work transfer due to shear along the radial, axial and tangential directions. In this paper, the physics of fluid flow and thermal separation are studied based on the heat and work transfer due to shear along all three directions. The work transfer due to the action of tangential shear is always from the cold to hot fluid layers and is the most dominant factor in the thermal separation process. The contribution increases considerably with hot cascading. However, the process of thermal separation degrades due to the effect of sensible heat transfer.     

有机染料敏化TiO2纳米晶多孔膜液体太阳能电池研究进展

对染料敏化TiO2纳米晶多孔膜太阳能电池的结构及原理进行了简单介绍,主要从TiO2薄膜、染料敏化剂和支持电解质3个方面提出了提高液态电池效率的途径.在此基础上,提出设计合理、有效光、热转化器是实现太阳能量最大利用的观点.     

Parts inspection by laser beam heat injection

When a pulse of laser radiation falls on a material surface, a certain amount of warming will occur which depends upon the surface properties of the material, particularly upon its absorptivity. The amount of warming will also depend upon what is underneath the surface and especially upon the amount of mass which is available for the thermal energy to expand into. If the warming process is monitored by an infrared detection system, one has a ready means of determining whether or not two parts are alike in their surface properties or in their internal features. An automatic, non-contact system is described which uses this principle for the inspection of solder joints on printed wiring boards at rates of up to 10 joints per second. With minor changes, the inspection system can be used to repair defective joints and to manufacture new ones by the reflow of solder paste or performs. Extensions of the inspection method are described with regard to the testing of bonds in metal sheets and to the measurement of paint thicknesses on metals.     

Numerical and experimental investigation on temperature distribution of the discontinuous welding

The main objective of this study is to generate new understanding and improve computer methods for calculating the thermal cycles and temperature distribution of 5A06 aluminum alloy structure during discontinuous welding. Predicting the thermal cycle also provides an estimate of the weld penetration and weld width. The submodeling technique was used to save computing time and improve calculation accuracy. The arc heat input was applied in the weld zone using different forms of surface, volumetric and combined heat flux distribution functions. In order to validate the thermal simulation model, temperature distribution at the weld backside was precisely measured by infrared thermography during the welding process. The simulation results showed that the model is quite sensitive to the energy distribution during the welding process, the effects of the pre-heating and re-heating are significant. The present simulation model can be used as a proper tool to investigate the effect of different metal inertia gas (MIG) process parameters.     

新能源和可再生能源

本文主要综述新能源和可再生能源中的太阳能、风能、燃料电池、海洋温差发电和可燃冰的原理及应用,以及各国的研究现状和发展动态.     

高性能热机械分析仪在先进陶瓷及粉末冶金烧结研究领域的应用

热分析法,已成为当今先进材料研究领域不可或缺的表征手段之一。在确定材料相图,评估热稳定性等方面均发挥着无可替代的重要作用。在粉末冶金及先进陶瓷领域,对材料的烧结过程的控制及相应的热膨胀信息的掌握一直是获得高性能产品的关键。而现阶段在相应领域广泛使用的常规热分析仪,尤其是热膨胀仪,基于仪器设计方面的局限,并不能完全胜任此项工作。本文结合应用实例,介绍了高性能热机械分析仪的工作原理及结构特点,阐述了其在先进陶瓷及粉末冶金领域的研究方法及独有优势。     

Electrically Assisted Ultrasonic Nanocrystal Surface Modification of Ti6Al4V Alloy

In this study, an innovative process, electrically assisted ultrasonic nanocrystal surface modification (EA‐UNSM), is used to process Ti6Al4V alloy. As compared with traditional UNSM, EA‐UNSM results in lower dislocation density and larger grains due to the thermal annealing effect caused by resistive heating. In addition, deeper plastic deformation layer is observed in the electrically assisted case. By supplying mechanical energy and thermal energy simultaneously, a strong dynamic precipitation effect is induced, which generates nanoscale precipitates in the EA‐UNSM‐treated Ti6Al4V alloy. These nanoscale precipitates can effectively pin dislocations during plastic deformation and thus significantly improve the surface hardness.     

Constraints on monitoring resin flow in the resin transfer molding (RTM) process by using thermocouple sensors

In this study, a thermocouple sensor system was used to monitor the resin transfer molding (RTM) process. These sensors are low-cost and durable; and they do not disturb the resin flow. They can be used if the inlet resin is either hotter or colder than the mold walls. In experiments of this study, much of the hot resin’s internal energy was transferred to cold mold walls by conduction, when the mold parts were made of a material with high thermal conductivity, such as aluminum. A mathematical model based on 1D flow and 2D unsteady energy conservation was developed to investigate the heat transfer between resin and mold walls. The numerical solution of this model is in qualitative agreement with the results of our experiments. The thermocouple sensor system developed is more useful with the following process parameters: low thermal conductivity of mold material, high resin flow rate, high temperature difference between inlet resin and initial mold walls, and high specific heat of resin. However, for the typical use of RTM materials and typical injection parameters, thermocouples should not be preferred over other sensor types and should be used with caution due to the shortcomings investigated in this study.     

Mechanism of droplet generation in silver thin films for organic light-emitting diode displays

Thin silver film is widely used as the cathode in organic light-emitting diode displays and it is generally fabricated using the thermal evaporation method. But during the evaporation process, there is an inevitable outgassing problem and this creates high viscosity bubbles in melted silver. When the bubbles break, the high energy released scatters silver droplets which damage the silver surface. In this study, we were able to decrease the number of droplets from 6,171 to 278 with a degassing process of 400 °C for 6 h before proceeding with a thermal evaporation process.