太阳能热泵系统中板式换热器模型分析

开发新能源和节能是寻求能源出路的两大重要途径,太阳能热泵供热系统以其显著的节能性和环保性具有广阔的发展前景。太阳能热泵相对空气源热泵具有明显的节能优势。以太阳能热泵系统应用的蒸发器和冷凝器为分析研究对象,讨论了板式换热器在太阳能热泵系统中应用的数学模型,并分析了其计算程序。讨论了太阳能热泵系统的节能特点及存在的问题。     

太阳能集热器与热泵联合供暖装置的实验研究

新能源开发与节能是解决能源短缺的两个关键途径,太阳能热泵(SAHP)系统因其突出的节能与环保特点而具有广泛和美好的前景.作者介绍了太阳能集热器与热泵联合供暖的实验装置,为了观察和测试系统和各部件的性能,对该装置进行了系统测试,获得了设计、安装和运行方面的资料,初步得出了若干有用的结论.     

太阳能热水辅助热泵干燥系统性能研究

搭建了太阳能热水辅助热泵干燥系统,以马铃薯片作为干燥物料,在冬季进行了不同热水温度的太阳能热水辅助热泵干燥实验,以及单一热泵干燥实验。实验结果表明：当辅助热水温度为30℃时,太阳能热水辅助热泵干燥系统制热量与COP值高于基础组,也高于辅助热水温度为20℃和10℃组的值,证明太阳能热水辅助热泵干燥系统能有效的提高系统效率,且辅助热水温度越高,太阳能热水辅助热泵系统更节能;同时总结了系统制热量与COP值随着干燥箱内温度、“薯片”水分迁移量的变化呈曲线上升的趋势。     

太阳能热泵-地板辐射采暖系统的应用研究

太阳能热泵技术是能源利用技术发展的一个重要方向，本文分析了太阳能热泵一地板辐射采暖系统的特点及其应用前景。为了探寻太阳能热利用的有效方式，结合所做的相关试验对比分析了连续运行与间歇运行模式下采暖系统的运行效果。结果表明间隙性运行方式可以充分利用地板辐射系统的蓄热特性，缩短热泵运行时间，提高系统的COP值，从而达到节能的效果。     

太阳能在热泵空调器开发中的应用

介绍了热泵空调器工作原理,阐述了太阳能热泵系统的类型,基于热力学观点,分析了太阳能辅助热泵系统的能量平衡关系及供热系数COP,指出比传统热泵空调器COP高出25%的太阳能辅助热泵空调器是我国热泵空调器的发展方向.     

不同热泵空调技术的对比

介绍了热泵技术的原理及分类,分别对空气源热泵、水源热泵、土壤源热泵、太阳能热泵空调系统的运行原理、特点、存在的问题及改进方法进行了分析;总结对比了这四种空调方式的优缺点,为不同地区选用热泵空调机组提供了参考依据。结论指出,通过合理热泵空调形式的应用,可以大大节约空调能耗,为我国节能减排工作做出重大贡献。     

浅谈太阳能-空气双热源热泵中央热水系统

本文针对新提出的一项技术一太阳能一空气双热源热泵中央热水系统进行了介绍,这项技术是在原有的太阳能技术的基础上研究出来的热水和热泵复合系统。该系统的主要热能是来自太阳能直射以及在空气中储存的太阳能,以较少的电能进行辅助驱动双热源热泵。该系统能够在任何气候环境下,经济的、节能的、全方位的满足人类对热水的需求。     

太阳能热水系统与跨临界二氧化碳热泵系统双向优化组合

太阳能是可再生能源。它资源丰富,既可免费使用,又无需运输,对环境无任何污染。为了促进节能与环境保护,太阳能热水系统已得到广泛应用。二氧化碳作为制冷工质具有一些独特的优势:环境友好物质(ODP=0,GWP=1),无回收问题;良好的安全性和化学稳定性;具有与制冷循环和设备相适应的热力学性质;具有良好的输运和传热性质。与常规制冷剂相比,二氧化碳跨临界循环的压缩比较小,约为2.5～4.0。介绍一种太阳能热水系统与跨临界二氧化碳热泵系统的组合系统,包括太阳能热水系统,二氧化碳热泵系统。针对不同气候条件,本系统分别采用制冷、热水、制热运行模式,从而实现热水、空调与热泵三大功能。     

太阳能辅助空气源跨临界二氧化碳热泵热水与空调系统初探

提出一种结构与控制均非常简单的太阳能辅助空气源跨临界CO2热泵空调热水系统，包括太阳能集热系统、CO2热泵系统以及室内室外换热系统；针对不同气候条件，可采用制热、制冷、热水、制热十热水、制冷十热水五种运行模式，实现热水和空调两大功能，具有节能环保的优点。     

小型太阳能热泵联合干燥系统的设计与分析

根据湛江市的气候条件,设计了小型的太阳能热泵联合干燥装置,并对该装置的热泵单独运行和太阳能热泵联合运行的制热系数进行了讨论,结果表明太阳能热泵联合运行可以提高热泵系统的制热效率。     

陶瓷电介质储能材料研究进展EI北大核心CSCD

为了更好地推动高储能密度和高效率无铅陶瓷介质电容器的研究与发展,本文综合介绍了陶瓷电介质储能材料的储能原理及分类,比较分析了近年来线性电介质、铁电体、弛豫铁电体和反铁电体储能材料的研究进展,主要研究体系和性能优劣。总结了陶瓷储能材料目前面临的挑战以及改善其储能性能的策略,展望了其未来在5G通信、新能源汽车、消费电子等工业应用中的发展及小型化、高耐电压性、高可靠性的技术发展趋势。     

Self-templating thermolysis synthesis of Cu2–xS@M (M = C,TiO2, MoS2) hollow spheres and their application in rechargeable lithium batteries

Nano Research - Owing to their unique structural stability and impressive long-term cycling performance, coated hollow structures are highly attractive for energy storage systems, especially...     

Hybrid Energy Harvesters: Toward Sustainable Energy Harvesting

Recently, sustainable green energy harvesting systems have been receiving great attention for their potential use in self‐powered smart wireless sensor network (WSN) systems. In particular, though the developed WSN systems are able to advance public good, very high and long‐term budgets will be required in order to use them to supply electrical energy through temporary batteries or connecting power cables. This report summarizes recent significant progress in the development of hybrid nanogenerators for a sustainable energy harvesting system that use natural and artificial energies such as solar, wind, wave, heat, machine vibration, and automobile noise. It starts with a brief introduction of energy harvesting systems, and then summarizes the different hybrid energy harvesting systems: integration of mechanical and photovoltaic energy harvesters, integration of mechanical and thermal energy harvesters, integration of thermal and photovoltaic energy harvesters, and others. In terms of the reported hybrid nanogenerators, a systematic summary of their structures, working mechanisms, and output performances is provided. Specifically, electromagnetic induction, triboelectric, piezoelectric, photovoltaic, thermoelectric, and pyroelectric effects are reviewed on the basis of the individual and hybrid power performances of hybrid nanogenerators and their practical applications with various device designs. Finally, the perspectives on and challenges in developing high performance and sustainable hybrid nanogenerator systems are presented.     

多羧酸基水溶性硫化染料染色和防皱整理双功能性研究

对合成的含多羧基水溶性硫化黑的染色和防皱整理双功能性进行了研究。考察了在以双氰胺、磷酸二氢铵及三乙醇胺等作为染色助剂情况下对合成染料染色效果的影响。该多羧酸基水溶性硫化染料在磷酸二氢铵及三乙醇胺等助剂存在及合适的焙烘温度下固色率能达到98．1％,同时被染棉织物显示出3级的良好湿摩擦牢度与优良的抗皱性能。     

Energy rating system for climate conscious operation of multi-unit residential buildings

Residential sector accounts for 17% of domestic energy use and 14% of the greenhouse gas emissions in Canada. Improving the energy performance of the Canadian residential building stock is vital in achieving climate action goals. A comprehensive review of popular building energy rating systems noted their lack of life cycle thinking. The scope of the popular rating systems is limited to operational performance, ignoring the condition of the assets. This paper proposes a condition assessment framework for the energy system of existing multi-unit residential buildings (MURB), which combines the concepts of asset rating and operational rating. Indicators were identified to define energy, environmental, economic, and asset performance of MURB. A life cycle assessment was conducted to quantify the overall environmental impacts of energy technologies from point of generation. A fuzzy logic-based approach was used to overcome the challenges due to data uncertainty and impreciseness. A case study was conducted for a residential building at UBC Okanagan, Canada. The weights at indicator level and category level were defined based on stakeholder consultation, while also considering different decision scenarios. A fuzzy rule-based approach was used to combine the different performance categories to obtain an overall condition rating. The results indicate that the performance of the case study building can be rated as “good” under operational, asset, and overall categories. The findings of this research can be used to improve the asset and operational management strategies in existing buildings and can inform the key stakeholders during the operational phase of the buildings.     

Citric acid/ZrO2 nanocomposite inducing thermal barrier and self-cleaning properties on protein fibers

The present research carried out to stabilize nano-ZrO₂ on the wool fabric using citric acid (CA) as a crosslinking agent and sodium hypophosphite (SHP) as a catalyst under UV irradiation. The influence of the amount of nano-ZrO₂ on the performance of wool fiber was investigated by the use of Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscope (EDX) and reflectance spectrophotometer (RS). The possible interactions between nano-ZrO₂ particles, cross-linking agent and wool free radicals were elucidated by the FTIR spectroscopy. Results indicated that the stabilized nano-ZrO₂ enhances the thermal stability of wool. Photo-catalytic activities of the coated wool were evaluated through degradation of methylene blue (MB) under UV irradiation.     

Recent Advances in 3D Graphene Architectures and Their Composites for Energy Storage Applications

Graphene is widely applied as an electrode material in energy storage fields. However, the strong π–π interaction between graphene layers and the stacking issues lead to a great loss of electrochemically active surface area, damaging the performance of graphene electrodes. Developing 3D graphene architectures that are constructed of graphene sheet subunits is an effective strategy to solve this problem. The graphene architectures can be directly utilized as binder‐free electrodes for energy storage devices. Furthermore, they can be used as a matrix to support active materials and further improve their electrochemical performance. Here, recent advances in synthesizing 3D graphene architectures and their composites as well as their application in different energy storage devices, including various battery systems and supercapacitors are reviewed. In addition, their challenges for application at the current stage are discussed and future development prospects are indicated.     

Chemical vapor deposition of spectrally selective surfaces for high temperature photothermal conversion

Chemical vapor deposition was adapted to the fabrication of multilayer thin film systems of the spectral selectivity required for photothermal solar energy conversion. The systems operate on the principle of an absorber-reflector tandem, the absorption of the solar photons being accomplished by a layer of polycrystalline or amorphous silicon and the thermal emittance being reduced by a silver or molybdenum reflector. The surfaces were tested for several thousand hours at 500°C without degradation of their optical performance.     

A review of material aspects in developing direct Z-scheme photocatalysts

Photocatalysis utilizes solar energy to produce clean fuels such as hydrogen or generate highly reactive species to subsequently break the organic pollutants into clean end products. Direct Z-scheme heterostructured photocatalysts can overcome the fundamental shortcomings in conventional photocatalysts and thus enable this green technology in tackling the energy crisis and environmental problems at the same time. Various approaches and numerous materials have been attempted in the hope of achieving high efficiency and broad effectiveness for practical applications. This work intends to provide a comprehensive and timely review on direct Z-scheme photocatalysts from the material’s point of view. The formation mechanisms based on the driving forces of the charge transfer are firstly discussed to guide the material design. Three mechanisms, namely internal electric field, interfacial defect-induced charge transfer, and facet-induced charge transfer, are identified and summarized. Various material systems are then extensively discussed and compared according to their applications, followed by the emerging material modification strategies for performance improvement. Lastly, the review provides the perspectives for future development. It is expected that the insights of this up-to-date review could guide the material design and performance improvement of the direct Z-scheme systems to achieve their maximum potentials.