水帆式水力发电技术概况

“水帆式水力发电技术”是青海省科委确定的科技攻关项目，已通过省级鉴定。该技术达到了国内外领先水平。世界上第一座野外水帆式水电站已于1996年8月在青海省乐都县亲仁乡建成发电，功率12．5kw。该电站的核心是“水帆机”，它与现有的水轮机根本不同，相应的水工建筑也根本不同。“水帆机”外形为方形长水槽，倾斜放置，发电机和机房位于上端（现水电站机房位于下端）。一个水帆机就取代（取消）了现水电站的如下四大部分：压力前他、压力钢管、水轮机和水轮机室（厂房地下部分复杂的水工建筑），加之“水帆机”本身结构简单，造价又比水…     

水帆式水力发电技术的研究和野外试验

阐述了水帆式水电站的基本结构和成本，给出了实验室和野外试验结果，并与现有电站进行了对比分析，经测试，水帆机效率可达８４．４％；发电机效率为８３％－９０％时，电站总效率可达６１％－７５．５％，每ｋＷ造价仅为现有小水电站的５０％左右；如对单机３０－５０ｋＷ的水帆电站做技术改进，每ｋＷ造价有可能降低到现有小水电站的３０％左右。     

铁电晶体热电转化回热循环的性能优化准则

考虑铁电晶体热电能量转化回热循环的有限时间性以及热阻和铁电介质的损耗等不可逆因素，定义回热循环能量转化的特征参量λ，对循环性能进行优化研究，给出铁电晶体热电转化最大输出功率状态下的优化准则以及功率与效率协调的优化准则，为回热式电晶体热电能量转化装置的优化设计提供理论依据。』     

微型风力热泵系统的研究

研究了利用风能的一种新型装置，将风能通过风力叶轮转化为机械能后，通过变速器带动微型制冷用压缩机，压缩机则与其它装置组成布雷顿热泵循环，利用热泵循环产生的热量加热居民水箱中的水，供给居民使用。通过计算分析，该方案是可行的，同时减少了能量转换环节，实现了可再生能源的合理利用，并且从另一个角度解决了风力资源的不稳定性问题。     

农村户用能源生态工程北方模式能量转化研究

应用系统能量学和热力学方法对户用能源生态工程北方模式的能量转化进行试验研究，通过系统模拟技术建立构成该模式的3个子系统的能量平衡方程。研究表明，日光温室种植子系统、畜圈饲养子系统和沼气池厌氧发酵子系统能量输出分别占总能量输出的21％，47％和32％，能量转化率分别达到1．37％、64％和84％，辅助能转化率为65％。该系统能量转化机制合理，是适合在中国北方农村地区推广的生态工程。     

合成氨装置一段转化炉系统的能平衡测试计算方法

本文阐述了合成氨装置一段转化炉系统能量平衡的测试及计算方法，在此基础上编制了通用的计算程序，利用该程序输入若干相关的测试数据，即可计算出能量平衡的所有指标，从而使复杂的计算得以简化，便于工程采用。     

汽轮机凝汽器结垢造成能源损失的量化分析

进行了汽轮机凝汽器结垢影响火力发电机效率的试验，计算了节能量，指出，及时清除凝汽器的结垢，能取得节能减排的实际效果。     

燃煤气的闭式STIG循环中气化系统能量转化效率的研究

针对燃煤气的闭式ＳＴＩＧ循环,给出气化系统能量转化效率的计算式,计算三种典型气化炉分别采用高温干法和常温湿法净化系统的能量转化效率,同时分析能量转化效率对整个循环系统效率的影响。     

综合使用可再生能源的能量转换装置(2011-X003)

本项目提出了一种综合使用可再生能源的能量转换装置。太阳能预先转化为电能,风能(海洋能、生物质能、地热能等)预先转化为机械能,如果把这两种能量输入到新型能量转换装置中,在出口获得的是两个     

新型太阳能光伏光热一体化系统性能实验研究

文章提出了一种新型热管式太阳能光伏光热(PV/T)一体化系统,并提出了能够表征主动式PV/T系统能量收益的参数—实际能量收益率。在同一工况下,对热管式PV/T系统和PV系统进行测试研究,分析不同影响因素对热管式PV/T系统光电转化效率、光热转化效率及实际能量收益率的影响规律。研究结果表明:当热管式PV/T系统的循环流量为320 L/h时,该系统的实际能量收益率最大;同一工质流量下,光热转化效率对热管式PV/T系统实际能量收益率的影响远大于光电转化效率;热管式PV/T系统的实际能量收益率比PV系统高29.09%。     

Recent progresses in porphyrin assisted hydrogen evolution

The indiscriminate exploitation of fossil fuels over a period of two centuries has eventually led us to a juncture where search for alternate energy sources and sustainable development has become inevitable. Solar energy remains the most reliable renewable energy source, efficient harnessing of which can serve to meet the future energy demands. Photo-assisted water splitting to generate hydrogen, a potential clean fuel has been the focus of current research in this field. Design and development of suitable materials for efficient solar energy conversion remains the major challenge to be tackled in this aspect. A cost-effective technology for conversion of solar energy is still a distant dream. The present paper attempts a general overview of the basic principles of water splitting with special focus on porphyrin-based systems as promising water splitting systems.     

一种评价能源利用方式的新方法

基于热力学第二定律的分析方法,按照能质系数的概念确定了电、天然气、煤、蒸汽、热水等各种形式的建筑用能及建筑物耗冷量、耗热量的能源品位高低;提出了一种评价能源利用方式的新方法。该方法利用能量转换系数(ecc/ECC)指标,可对包括园区热电冷联供系统、建筑物制冷供热系统、能量输配系统及末端用能设备在内的一系列用能环节的能源利用效率进行评价,作为确定建筑物用能方式的决策依据。     

变频技术在空调水系统中的应用与节能分析

根据空调水系统在不同工况下运行的性能与特点 ,分析了冬夏及部分负荷运行时空调水系统的流量和扬程的差异。提出了空调水系统在冬夏及部分负荷运行时 ,循环水泵应采用变频技术 ,合理配备。并举出工程实例分析比较循环水泵变频运行的特性与耗能情况。     

Molecular dynamics simulation for homogeneous nucleation of water and liquid nitrogen in explosive boiling

Molecular dynamics simulations are carried out to study the energy conversion in the homogeneous nucleation processes of the explosive boiling induced by laser heating. Liquid nitrogen and water are investigated as the working fluid. Velocity scaling method is applied to realize the heating process. Three influencing factors, the initial equilibrium temperature of the liquid, the area of the heating zone and the heat quantity are analyzed. It is found that the conversion ratio of energy between heat quantity and potential energy is from 66% to 78% in the process of heating. The influence of the heat quantity on the energy conversion of liquid nitrogen is the same in trend as that of water. The influence of the initial equilibrium temperature and the area of the heating zone on the liquid nitrogen is less than that of water. The difference of energy conversion between water and liquid nitrogen is pretty dramatic, which is because of the hydrogen bond formed by the Coulombic interaction among water molecules.     

Hydrokinetic energy conversion systems and assessment of horizontal and vertical axis turbines for river and tidal applications: A technology status review

The energy in flowing river streams, tidal currents or other artificial water channels is being considered as viable source of renewable power. Hydrokinetic conversion systems, albeit mostly at its early stage of development, may appear suitable in harnessing energy from such renewable resources. A number of resource quantization and demonstrations have been conducted throughout the world and it is believed that both in-land water resources and offshore ocean energy sector will benefit from this technology. In this paper, starting with a set of basic definitions pertaining to this technology, a review of the existing and upcoming conversion schemes, and their fields of applications are outlined. Based on a comprehensive survey of various hydrokinetic systems reported to date, general trends in system design, duct augmentation, and placement methods are deduced. A detailed assessment of various turbine systems (horizontal and vertical axis), along with their classification and qualitative comparison, is presented. In addition, the progression of technological advancements tracing several decades of R&D efforts are highlighted.     

直流变频空气源热泵热水器的实验研究

针对普通定频空气源热泵热水器不能在宽负荷和宽温度条件下运行等缺陷,提出一种直流变频空气源热泵热水器。通过对样机进行实验,得出了制热量、功率、COP值、吸气温度、排气温度等性能参数随压缩机运行频率的变化规律。结果表明直流变频热泵热水器能在宽负荷、宽温度条件下稳定运行。     

Autonomous BDFIG-wind generator with torque and pitch control for maximum efficiency in a water pumping system

This paper presents and analyzes the operation strategy for an autonomous wind energy conversion system oriented to water pumping. It consists of a wind turbine with a Brushless Doubly-Fed Induction Generator (BDFIG), electrically coupled with a squirrel cage induction machine moving a centrifugal type water pump. Because of no brushes and slip rings, the BDFIG is suitable for autonomous systems, which often work in hard conditions. Additionally, the power flow on the BDFIG principal stator could be driven from a fractional power converter connected on the auxiliary stator winding. This Turbine-BDFIG and Motor-Pump configuration provides a high robustness and reliability, reducing the operational and maintenance costs. The operation strategy proposes, for wind speeds smaller than the rated, to maximize the volume of water pumped based on the optimization of the wind energy capture. To do that, a sliding mode control tracks the optimal turbine torque by means of a torque control. Meanwhile, for wind speeds greater than the rated, a pitch control keeps the water pump within the safe operation area by adjusting the speed and power of the turbine in their rated values. To assess and corroborate the proposed strategy, simulations with different wind profiles are made.     

Photocatalytic hydrogen production: A solar energy conversion alternative?

Since the beginning of earth, ultra-violet rays from the sun have been splitting water molecules in the upper reaches of the atmosphere, producing hydrogen and oxygen. At the same time, photosynthesis has been sustaining life on earth by utilizing the longer wavelengths of sunlight to split carbon and water molecules forming carbohydrates and oxygen. Attempts are being made to imitate these processes for the purpose of harnessing solar energy for man's use.This paper presents a state-of-the-art review of photolysis of water by sunlight with consequent energy storage in the molecular bonds of hydrogen and oxygen. The photocatalytic solar energy conversion methods reviewed are classified according to the photosensitizer type. That includes catalysts such as compound salts, compound semi-conductor crystals and photosynthetic dyes. An assessment of these methods concludes that photolysis of water as a solar energy conversion process does not seem feasible at present or for the immediate future. On the other hand, efficiency estimates indicate that with research emphasis this unconventional energy conversion method may prove to be a long-term alternative in harnessing solar energy for man's use.     

Power quality analysis of wind farm connected to Alaçatı substation in Turkey

This paper presents simulation results and power quality measurements of a wind farm. The wound rotor induction generator at 600 kW is employed for power conversion in the wind energy conversion system (WECS). This induction machine is connected to the drive circuit via rotor terminals and speed control is carried out by means of chopper circuit. The model used in the package program is experimentally tested on the single machine drive system at 3.5 kW in the laboratory, after which the power quality issues of the wind farm are investigated by using the same model for 12 wind turbines in PSCAD.     

On the ocean heat budget and ocean thermal energy conversion

Ocean water covers a vast portion of the Earth's surface and is also the world's largest solar energy collector. It plays an important role in maintaining the global energy balance as well as in preventing the Earth's surface from continually heating up because of solar radiation. The ocean also plays an important role in driving the atmospheric processes. The heat exchange processes across the ocean surface are represented in an ocean thermal energy budget, which is important because the ocean stores and releases thermal energy. The solar energy absorbed by the ocean heats up the surface water, despite the loss of heat energy from the surface due to back‐radiation, evaporation, conduction, and convection, and the seasonal change in the surface water temperature is less in the tropics. The cold water from the higher latitudes is carried by ocean currents along the ocean bottom from the poles towards the equator, displacing the lower‐density water above and creating a thermal structure with a large reservoir of warm water at the ocean surface and a large reservoir of cold water at the bottom, with a temperature difference of 22°C to 25°C between them. The available thermal energy, which is the almost constant temperature water at the beginning and end of the thermocline, in some areas of the oceans, is suitable to drive ocean thermal energy conversion (OTEC) plants. These plants are basically heat engines that use the temperature difference between the surface and deep ocean water to drive turbines to generate electricity. A detailed heat energy budget of the ocean is presented in the paper taking into consideration all the major heat inputs and outputs. The basic OTEC systems are also presented and analyzed in this paper. Copyright © 2011 John Wiley & Sons, Ltd.