国内可再生能源文献信息

GN040401以空气为携热介质的开式太阳能吸收式制冷循环研究与分析.徐士鸣,刘渝宏.太阳能学报,2004,25(2):205-209.以空气为携热介质的开式太阳能吸收式制冷循环为研究对象,根据工作循环的特点给出了循环工作流程及计算方法,并对循环进行了详细的计算和分析,得出了循环COP值、制冷量、与湿空气出口处工作溶液与空气的水蒸气分压力差随热空气温度、环境温度和相对湿度之间的关系。通过研究发现,当热空气达到一定温度时,循环具有较好的稳定性。与闭式太阳能吸收式制冷循环相比,开式循环具有启动快、COP值高、系统简单、造价低等优点,特别适…     

以空气为携热介质的开式太阳能吸收式制冷循环研究与分析

以空气为携热介质的开式太阳能吸收式制冷循环为研究对象，根据工作循环的特点给出了循环工作流程及计算方法，并对循环进行了详细的计算和分析。得出循环COP值、制冷量与湿空气出口处工作溶液与空气的水蒸气分压力差随热空气温度、环境空气温度和相对湿度之间的关系。通过研究发现，当热空气达到一定温度时，循环具有较好的稳定性。与闭式太阳能吸收式制冷循环相比，开式循环具有启动快、COP值高、系统简单、造价低等优点，特别适合在高温炎热地区使用。     

以空气为携热介质的开式太阳能蓄能热泵循环研究与分析

以空气为携热介质的开式太阳能吸收式热泵系统为研究对象，在原有制冷循环基础上，根据冬季蓄能热泵循环运行特点对系统进行改进；并以西安地区为例对循环进行计算和分析，探讨其蓄能情况和影响系统工作性能的因素。     

以空气为携热介质的开式太阳能蓄能热泵循环特性研究

以空气为携热介质的开式太阳能吸收式热泵系统为研究对象，在原有开式制冷循环的基础上，根据冬季蓄能热泵运行特点对系统进行改进；并以北京、西安、兰州3个地区为例，结合当地的气象条件，对循环进行计算并分析影响系统工作性能的因素。     

一种新型混合吸收式制冷循环的性能分析

该文提出一种新型吸收式循环，可以较好利用太阳能实现制冷，解决传统吸收式系统在利用太阳能实现制冷时存在的弊端。这种新型混合式吸收式制冷循环在两级吸收式循环的基础上增设了一个附加高压发生器，发现影响系统COP值的因素主要是LiBr溶液浓度与低压发生器中的压力。在溶液浓度与压力的允许范围内时，新型循环的高压发生器再生出LiBr溶液与低压吸收器的吸收后的溶液混合，提高高压吸收器吸收剂浓度从而减小其压力。本文主要分析了混合吸收式制冷循环的各种性能特性，得出影响系统热力系数(COP)可达0．55，驱动热源的可利用温差最高可达35℃。     

用于深度冷冻的自行复叠吸收制冷循环理论研究

提出了一种可利用热能获得深度冷冻的吸收制冷循环，通过对新循环与传统吸收制冷循环最低制冷温度的比较，证明新循环能取得比传统吸收式制冷低得多的蒸发温度。对新循环的不同工况进行了计算和分析，发现新循环的冷凝蒸发器中两股流体热容量是否匹配是决定COP值的关键因素。     

太阳能溴化锂吸收式制冷技术的研究进展

介绍了太阳能澳化锂吸收式制冷循环的工作原理和系统构成,具体阐述了该制冷循环的几种典型结构,包括单效、双效、两级以及三效涣化锂吸收式制冷循环,分析了各种制冷循环的优缺点以及目前研究进展;进一步讨论了太阳能澳化锂吸收式制冷机组的性能特点受冷媒水出口温度、冷却水进口温度、加热蒸汽温度、污垢系数及不凝性气体等诸多因素的影响;提出了太阳能溴化锂吸收式制冷技术现存问题,最后指出,随着科学技术的发展和绿色建筑的兴起,太阳能溴化锂吸收式制冷将会有非常大的发展前景。     

一个高效的两级吸收式制冷新循环

根据两级吸收式制冷循环本身的特点提出了一种新的两级吸收式制冷循环。研究结果表明:新循环比传统循环具有更高的效率和更低的吸收器负荷,而且在相同的蒸发温度时,发生终了温度越低,新循环相对传统循环COP的提高幅度以及吸收器负荷的减少幅度越大;相同发生终了温度时,蒸发温度越低,新循环相对传统循环的COP提高幅度以及吸收器负荷的减少幅度越大。     

新型1.x级溴化锂吸收式制冷机循环

文中介绍了一种新型1．x级溴化锂吸收式制冷机循环。该新型循环在原有两级溴化锂吸收式制冷循环基础上增加了一个附加高压发生器．使部分流体按单效循环工作．同时可将热源进出口温差加大到25～30℃左右，在热水进出口温度为85℃和60℃时，热力系数COP则能达到0．58左右。该循环非常适合于利用太阳能等低势热能制冷，能够产生显著的节能和环保效果。     

新型太阳能吸收式制冷循环的性能分析

在两级溴化锂吸收式制冷循环的基础上,提出了一种由太阳能驱动的新型吸收式制冷循环,并对其进行性能分析。通过大量计算,分析结果表明,在现有太阳能集热器所能提供的热水温度范围内,新型太阳能吸收式制冷循环有较高的热力系数。该循环系统的中间压力、中间浓度对系统的热力系数和热源可利用温差有较大影响。     

Hydrogen absorption by metallic thin films detected by optical transmittance measurements

The hydrogen absorption by bilayers of Pd/Nb and Pd/Ti, grown on glass substrates, was studied by measuring changes in optical transmittance and reflectance in the visible range (wavelengths between 400 nm and 1000 nm) of the films at hydrogen pressures between 3.99 × 10² and 4.65 × 10⁴ Pa. The electrical resistance of the films was also measured during absorption to correlate with the optical data. All the films were grown by a controlled sputtering technique in high vacuum. Pd films ranging in thickness between 4 nm and 45 nm were also characterized when the films were exposed to a hydrogen pressure. The resistance and transmittance of all the Pd samples increased with the uptake of hydrogen until saturation occurred. For Pd/Ti bilayers, fast uptake of hydrogen was deduced from a transmittance increase, indicating hydrogen absorption in the Ti layer. In the case of the Pd/Nb bilayer, a decrease in transmittance was observed, indicating that hydrogen was not absorbed in the Nb layer. The transmittance decrease could be explained by a reduction of Nb native oxide by the hydrogen at the surface.     

Hydrogen production by splitting water on solid acid materials by thermal dissociation

Conventionally, there have been three basic ways of research on H₂ production from H₂O-splitting with solar energy: photo-catalytic, photo-electrochemical and thermochemical. Among them the thermal dissociation of H₂O has been considered the most efficient, because it is a single step energy conversion process and gives much higher conversion efficiency than those resulted from other methods. However, the major stumbling block of thermal dissociation of H₂O has been the requirement of a high dissociation temperature which causes problems both with materials for the reactor and with energy conversion efficiency for the process. In this study, we show that the dissociation temperature can be drastically lowered when H₂O is thermally dissociated on solid acid materials. A probable mechanism of the thermal H₂O-splitting on solid acid materials is also presented, based on some experimental results of this study and reports in the literature.     

Light-driven biological hydrogen production by Escherichia coli mediated by TiO2 nanoparticles

Photocatalytic hydrogen production using an inorganic bio-hybrid system can contribute to the proficient utilization of light energy, but it would necessitate the development of novel approaches for preparing a new hydrogen-producing biocatalyst. In this study, we developed a hybrid system to produce hydrogen, whereby the highly efficient light-harvesting inorganic semiconductor (TiO₂) was mixed with Escherichia coli to form a biocatalyst with the addition of an electron mediator (MV²⁺) under different visible light irradiation. Under this hybrid system, the hydrogen production by E. coli was light intensity-dependent showing maximum production at 2000 W m⁻², with a 2-fold increase in the hydrogen production compared to that without TiO₂. The experiments on the continued cycle of hydrogen production revealed that the production could be continued for at least 3 cycles of 5 h incubation for each. A possible pathway utilizing glucose for hydrogen production by the hybrid system was proposed based on the analysis of the levels of metabolites. A feasibility study was also conducted using natural sunlight for hydrogen production by the hybrid system. Overall results demonstrated that whole cells of E. coli could be employed for photocatalytic hydrogen production where the intactness of the E. coli was retained under experimental conditions.     

Electrowetting-on-Dielectric by Wireless Powering

Electrowetting-on-dielectric (EWOD), in which microdroplets are manipulated using electrical inputs, has drawn a great deal of attraction with applications of digital lab-on-a-chip and hot-spot cooling. In most EWOD actuations, the commonly used powering method is wired transmission, which may not be suitable for isolating and employing EWOD devices in hard-to-reach areas. In this study, we investigate wireless power transmission for EWOD utilizing inductive coupling. Since EWOD is typically operated by a high-input voltage although the current is minimal, wireless EWOD also requires a similarly high voltage at the receiver, unlike conventional inductive coupling. To meet this condition, the resonant inductive coupling method at a high resonant frequency is introduced and investigated. To optimize the transmission efficiency, we study the effects of many parameters, such as the frequency, inductance, and capacitance at the transmitter and receiver, the gap between the transmitter coil and receiver coil, and the droplet size, by measuring the voltage at the receiver and the contact angle of the droplet placed on a wirelessly operated EWOD chip. In addition, by applying amplitude modulation to the resonant inductive coupling, wireless AC-EWOD, which generates droplet oscillations and is a common mode for EWOD droplet handling, is also achieved. Finally, it is successfully demonstrated that a droplet is transported laterally by using an array of electrodes, which is also powered by an amplitude-modulated wireless signal.     

Hydrogen generation by aluminum corrosion in seawater promoted by suspensions of aluminum hydroxide

Nowadays, new processes of H₂ generation from water via Al corrosion are mainly limited by Al passivation. Here we report on the systematic assessment of H₂ production by corrosion of Al in seawater suspensions prepared with NaAlO₂. The reported results are encouraging, since it was observed that seawater suspensions tested can prevent Al passivation during H₂ evolution, reaching 100% yields at ca. 700 cm³ H₂ min⁻¹. XRD analysis revealed the formation of solid Al(OH)₃ (bayerite) in initial seawater suspensions. So, model suspensions were prepared using NaAlO₂ + Al(OH)₃ in distilled water, which even improved the results obtained in seawater. Suspended particles of Al(OH)₃ act as nuclei in a mechanism of seeded crystallization, which prevents Al surface passivation. Moreover, a synergistic effect of Al(OH)₃ suspensions in combination with NaAlO₂ solutions was key in promoting Al corrosion. The effect of NaCl in aqueous suspensions was also studied, but it was insignificant compared to this synergistic effect. The composition of suspensions was optimized and a 0.01 M NaAlO₂ solution with 20 g dm⁻³ Al(OH)₃ was selected as candidate to generate H₂ at pH ca. 12 with high efficiency. Consecutive runs of the selected composition were performed obtaining ca. 90% yields in all of them.     

Exploitation of solar energy collected by solar stills for desalination by membrane distillation

The aim of this work was to evaluate the technical feasibility of producing potable water from simulated seawater by integrating a membrane distillation module with a solar still. The relatively hot brine in the solar still was used as a feed to the membrane module. The synergistic action of the solar still and the membrane module in the production of potable water was quantified. For this purpose, two types of experiment were conducted, indoor experiments and outdoor experiments. The sensitivity of the permeate flux to the brine temperature, flow rate, salt concentration and solar irradiation were all investigated. Overall, the flux of water from the solar still was no more than 20% of the total flux. The brine temperature significantly affected the flux of both the solar still and the membrane module, while the effect of salt concentration was marginal. The effect of these process parameters was more noticeable in the membrane module than in the solar still.     

Optimization of hydrogen production by filtration combustion of natural gas by water addition

The effect of adding steam during filtration combustion of natural gas–air mixtures was studied with the aim to evaluate the optimization of hydrogen production. Temperature, velocity, chemical products of combustion waves, and conversion from fuel to H₂ and CO were evaluated in the range of equivalence ratio (φ) from stoichiometric (φ = 1.0) to φ = 3.0 and steam content in the mixture from 0% to 39%, at filtration velocities from 12 to 25 cm/s. Numerical simulation was carried out using GRI-MECH 3.0. Results suggest that H₂ and CO concentrations, dominant for rich and ultrarich combustion, are products from partial oxidation and steam natural gas reforming processes. Experimental and numerical results show that hydrogen yield increase with an increase of steam content in the natural gas–air mixtures.     

Hydrogen production by steam-oxidative reforming of bio-ethanol assisted by Laval nozzle arc discharge

The hydrogen production from an easily transported liquid feedstock can be an efficient alternative for fuel cells application. The steam-oxidative reforming of bio-ethanol by a novel gliding arc discharge named Laval nozzle arc discharge (LNAD) was investigated in this paper at low temperature and atmospheric pressure. The conversion efficiency and product distributions, mainly of H₂ and CO, were studied as functions of O/C ratio, S/C ratio, the ethanol flow rate and input power. The voltage–ampere (V–I) characteristic is also discussed here concerning the non-thermal plasma effect on the bio-ethanol reforming. A high conversion rate and fair H₂ yield have been achieved, 90% and 40% respectively. When the ethanol flow rate (G_ethanol) was 0.15 g s⁻¹ and S/C = 2.0, the minimum specific energy requirement of H₂ and CO were achieved at O/C = 1.4 with the specific energy input of 55.44 kJ per ethanol mole, 72.92 kJ mol⁻¹ and 80.20 kJ mol⁻¹ respectively. The optimal conditions for ethanol reforming seem to be S/C = 2.0 and O/C = 1.4–1.6, which are higher than those of the reaction's stoichiometry. This paper shows interesting results in comparison with the ethanol reforming assisted by other discharges. Compared with others, it features good conversion rate, low energy consumption and significantly reduced nitrogen oxide emission.