太阳能热发电发展现状及关键技术战略研究

简明介绍了三种太阳能热发电系统的基本原理及其特点,综述了太阳能热发电的国内外发展现状,着重分析了太阳能热发电所涉及的关键技术,包括聚光镜、吸热器、跟踪系统、储热材料、太阳能热机,指明了未来中国发展太阳能热发电技术所需突破的瓶颈与限制。     

应用于大功率弹载微波组合的相变储热模块设计

近年来，随着弹载电子设备集成度越来越高，内部热耗不断增加，如何实现设备的高效热管理，成为制约弹载电子设备进一步发展的重大难题。该文提出了一种应用于大功率弹载微波组合的相变储热模块，通过仿真分析手段研究了储热模块主体结构对储热模块整体储热性能的影响。综合考虑可制造性、质量、储热能力等多方面因素后，确认了储热模块的结构形式和最终选用的相变介质材料。利用增材制造技术加工出储热模块样品，并搭建热测试平台完成了该样品的散热效果评估。实验表明，在60℃环境下，模块总热耗为211 W,工作10 min后，模块表面最高温度为104.1℃,满足组合使用要求。该储热设计技术有效地解决了模块短时大功率下温升过高的问题，在弹载电子设备热管理领域有着广阔的应用前景。     

太阳能-混凝土桩储热系统经济性及节能性分析

太阳能混凝土桩储热系统是节约能源、减少温室气体排放、高效开发与利用地下热能的新技术。在长春某别墅项目上应用太阳能混凝土储热桩系统,分析其工程造价,并分别与空调系统、地源热泵系统作了经济性分析与比较。建筑物采用太阳能混凝土桩储热系统可以实现冬季零能供暖,夏季零能制冷,每年最少节煤量可以达到17．72kg标准煤／m^2;吉林省地源热泵总应用面积要达到800万m^2,如采用太阳能混凝土储热系统,每年将节煤1．4×10^8kg,每年二氧化碳减少排放3．71×10^8kg,经济和节能效益巨大。     

基于热光效应的智能窗薄膜材料

基于半导体和金属间的相变特性,重点介绍了基于热光效应的二氧化钒薄膜材料,描述了当前国内外的研究进展.给出了能应用于智能窗的纳米二氧化钒薄膜材料,并与常规的二氧化钒薄膜材料进行了分析比较.对这种智能窗薄膜材料的原理与应用前景进行了评述.可以预计,随着对太阳能材料的不断研究与开发,基于热光效应的智能窗薄膜材料在太阳能利用方面将具有巨大潜力.     

碟式斯特林太阳能小型直流发电系统的研究

随着社会的进步和发展,人们对于清洁能源的需求逐渐增大,因此,针对太阳能的开发利用和实践研究开始成为重点的研究对象。传统的太阳能热发电技术使得太阳能源没有得到充分的利用,很多能量被浪费。相关的研究资料和实验证明,碟式太阳能热发电在各种太阳能热发电中效率最高、应用效果最好,据此,我们选择碟式太阳能斯特发电系统作为研究对象,希望可以提高太阳能的综合利用效率,为相关人员起到抛砖引玉的作用。     

相变热控在高空光学遥感器CCD组件中的应用

为保证高空光学遥感器CCD组件所需的温度水平,利用石蜡类材料的相变储热特性,设计了一种相变热控方案。分析了相变热控中封装容器及导热增强体材料。利用热平衡方程,计算了相变材料用量,设计了封装容器及导热增强体。通过CCD组件热试验测试了热控方案的热控效果。结果表明:在CCD组件连续工作2 h情况下,未采用相变热控方案的CCD组件温度范围为18～41.4℃,而采用相变热控方案的温度范围为18～28℃,满足热控指标要求。该相变热控已成功应用于某高空光学遥感器,可以作为其他航空光学遥感器CCD组件热控设计的参考。     

美国开发新材料储存太阳热能 为研究铺平道路

美国研究人员最近开发出一种新材料,能够按需储存和释放热能。以这种材料制成的储热设备不但能量存储密度大,还具有成本低、运输方便、储能时间长的特点,有望开创一种捕获和存储太阳能的全新方式。     

混凝土储热桩地下蓄热过程温度场数值模拟研究及分析

太阳能混凝土桩储热技术是以太阳能和混凝土桩作为复合热源的热泵系统,在混凝土桩内部埋设换热管,利用太阳能集热板把热量通过混凝土桩中的换热管储存在土壤中。采用柱热源模型对混凝土储热桩进行了180天的连续蓄热过程模拟计算,对地下土壤温度场进行分析,认为在4 m的桩间距下能量桩间的相互影响较小。     

研究开发出太阳能储存新材料

日前,美国研究人员开发出一种新材料,能够按需储存和释放热能。以这种材料制成的储热设备不但能量存储密度大,还具有成本低、运输方便、储能时间长的特点,有望开创一种捕获和存储太阳能的全新方式。相关论文发表在《纳米快报》杂志上。     

美开发出太阳热能储存新材料

<正>日前,美国研究人员开发出一种能够按需储存和释放热能的新材料。以这种材料制成的储热设备不但能量存储密度大,还具有成本低、运输方便、储能时间长的特点,有望开创一种捕获和存储太阳能的全新方式。相关论文发表在《纳米快报》杂志上。     

太阳能与空气能双热源热泵系统实验平台设计

为解决太阳能和空气能利用中存在的能量转换效率低的问题,设计了太阳能与空气能双热源热泵系统实验平台。实验平台主要由变频压缩机、PV/T蒸发器、风冷蒸发器、蓄热水箱、电子膨胀阀、数据采集与控制系统等组成,以太阳能和空气能作为热源,R134a作为制冷工质,通过控制电磁阀和电子膨胀阀,实现3种运行模式。利用PLC和组态软件实现实验参数采集与监控,并能开展一系列综合性、创新性实验,满足科研与专业教学的需要。     

Engineering the Thermal Conductivity of Functional Phase‐Change Materials for Heat Energy Conversion,Storage, and Utilization

Thermal energy storage technologies based on phase‐change materials (PCMs) have received tremendous attention in recent years. These materials are capable of reversibly storing large amounts of thermal energy during the isothermal phase transition and offer enormous potential in the development of state‐of‐the‐art renewable energy infrastructure. Thermal conductivity plays a vital role in regulating the thermal charging and discharging rate of PCMs and improving the heat‐utilization efficiency. The strategies for tuning the thermal conductivity of PCMs and their potential energy applications, such as thermal energy harvesting and storage, thermal management of batteries, thermal diodes, and other forms of energy utilization, are summarized systematically. Furthermore, a research perspective is given to highlight emerging research directions of engineering advanced functional PCMs for energy applications.     

An overview of state of the art and research in the fields of sensible, latent and thermo-chemical thermal energy storage

Due to the increase in volatile renewable power and heat generation (wind or solar), thermal energy storage (TES) has obtained growing importance and interest. The technology can be distinguished into three main types: sensible, latent and thermochemical storage. Apart from low and medium temperature heat applications, high temperature TES also is an attractive means to store power in the form of heat (before the thermodynamic transformation process). Thermochemical storage allows for long duration seasonal storage of energy.     

Thermal Conductivity of Amorphous Materials

Thermal conductivity is one of the most fundamental properties of solid materials. The thermal conductivity of ideal crystal materials has been widely studied over the past hundreds years. On the contrary, for amorphous materials that have valuable applications in flexible electronics, wearable electrics, artificial intelligence chips, thermal protection, advanced detectors, thermoelectrics, and other fields, their thermal properties are relatively rarely reported. Moreover, recent research indicates that the thermal conductivity of amorphous materials is quite different from that of ideal crystal materials. In this article, the authors systematically review the fundamental physical aspects of thermal conductivity in amorphous materials. They discuss the method to distinguish the different heat carriers (propagons, diffusons, and locons) and the relative contribution from them to thermal conductivity. In addition, various influencing factors, such as size, temperature, and interfaces, are addressed, and a series of interesting anomalies are presented. Finally, the authors discuss a number of open problems on thermal conductivity of amorphous materials and a brief summary is provided.     

Single‐Walled Carbon Nanotube/Phase Change Material Composites: Sunlight‐Driven,Reversible, Form‐Stable Phase Transitions for Solar Thermal Energy Storage

The development of solar energy conversion materials is critical to the growth of a sustainable energy infrastructure in the coming years. A novel hybrid material based on single‐walled carbon nanotubes (SWNTs) and form‐stable polymer phase change materials (PCMs) is reported. The obtained materials have UV‐vis sunlight harvesting, light‐thermal conversion, thermal energy storage, and form‐stable effects. Judicious application of this efficient photothermal conversion to SWNTs has opened up a rich field of energy materials based on novel SWNT/PCM composits with enhanced performance in energy conversion and storage.     

Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator

In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12°C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction.     

大功率LED照明的驱动和散热设计

对大功率LED光源的驱动电源和散热特性进行了分析。通过对大功率LED驱动电源的应用效率和光源热量产生、热源传导方式及热流特性的研究,提出了优化改进驱动电路设计和结构设计方法,在驱动电路设计中通过升/降压恒流电路、采用工频变压整流设计提高电源的利用率,降低电源耗热;在结构设计中通过优化改进翅片材质及界面材料、改进翅片结构、加装热管和均温板几种方式进一步提高散热效果,从而使产品的质量和性能得到全面提升。     

功率电子散热技术

现代功率电子设备功耗越来越大,体积越来越小,对散热的要求也越来越高。文章介绍了目前常用于功率电子设备的风冷、水冷、微管道散热器、热管技术等散热技术,阐述了各种散热技术的原理、特点,并介绍了最新的国内外学者的研究成果。     

大功率LED低热阻封装技术进展

散热是大功率LED封装的关键技术之一,散热不良将严重影响LED器件的出光效率、亮度和可靠性。影响LED器件散热的因素很多,包括芯片结构、封装材料(热界面材料和散热基板)、封装结构与工艺等。文章具体分析了影响大功率LED热阻的各个因素,指出LED散热是一个系统概念,需要综合考虑各个环节的热阻,单纯降低某一热阻无法有效解决LED的散热难题。文中还对国内外降低LED热阻的最新技术进行了介绍。