槽式太阳能热发电真空集热管技术

分析了真空集热管的结构和性能,制造工艺和存在的问题.同时比较了现有的几种真空集热管的性能参数,预测了真空集热管的发展方向.     

太阳能热发电系列文章(12)聚光类太阳能热发电中的热管式真空集热管

介绍了热管技术和热管式真空集热管;设计了几种热管式真空集热管;阐述了热管式真空集热管在槽式和碟式太阳能热发电系统中的应用。     

太阳能热发电系列文章（12） 聚光类太阳能热发电中的热管式真空集热管

介绍了热管技术和热管式真空集热管；设计了几种热管式真空集热管；阐述了热管式真空集热管在槽式和碟式太阳能热发电系统中的应用。     

太阳能热利用

一种家用太阳能吸附式中央空调；一种全玻璃真空太阳集热管的尾部固定结构；一种全玻璃真空太阳集热管；可避免真空集热管破裂的太阳能热漏洞百出器；海水源热泵机组[编者按]     

新型相变蓄热式太阳能集热管及热性能研究

结合太阳能真空集热管和相变蓄热材料的特点,提出了一种集热/蓄热一体化的新型相变蓄热式太阳能集热管,该集热管主要由金属-玻璃真空集热管、螺旋换热管和相变蓄热材料组成。通过室外蓄放热性能实验进行性能测试,结果表明:该新型相变蓄热式太阳能集热管集热效果良好,集热温度可达80℃以上,可很好地应用于热水供暖领域;以石蜡为相变蓄热材料,单根集热管的蓄热量可达3.25 MJ;放热过程中,有效得热量为873.6 kJ,放热损耗率为0.602;在保温性能上,温降率达1.67℃/h,保温性能待进一步提高。     

太阳能真空集热管的结构种类与特点

太阳能真空集热管按真空封装结构可分为两大类：全玻璃真空集热管和玻璃－金属真空集热管,从取热方式、使用温度和性能要求的不同又有各种不同的内部结构。本文对国内外一些有代表性的太阳能真空集热管的结构种类和特点做了综述。     

槽式太阳能集热管热性能评估方法

真空集热管是槽式太阳能聚光集热系统的核心部件之一.集热管工作过程中通过辐射换热、对流换热和热传导的方式将热量传递给环境,这部分传递到环境中的热量称为集热管的热损失.真空集热管的热损失是聚光集热系统热损失或总能量损失的主要组成,在很大程度上决定着聚光集热器的光-热转换效率,因此对集热管热性能的正确评估对聚光集热系统的研究至关重要.本文对槽式太阳能集热管热性能的计算、评估分析方法等进行了分析.     

用量热法测定全玻璃真空集热管的热性能

真空集热管的采光面积小、热容大,用常规的瞬时法测定热性能,既费时又不准确,有必要寻求一种简捷而又准确的试验方法,以适应真空集热管热性能批量抽检的需要。我们以量热法为基础,对真空集热管的热性能进行了研究。     

太阳能热利用

太阳能真空集热管 专利申请号：CN200720005006.3 公开号：0N201037701 申请人：北京天瑞星真空技术开发有限公司 本实用新型为一种太阳能真空集热管，包括金属内管、玻璃管。金属内管套入玻璃管之中，玻璃管的端部与金属内管密封连接，连接处设有金属波纹管和玻璃金属过渡管，玻璃金属过渡管包括多层玻璃和多层金属，两者相互间隔布置，并密封压制在一起；将玻璃管和金属内管连接起来，     

槽式太阳能发电

<正>槽式太阳能热发电系统属于线聚焦太阳能热发电系统,其关键部件是真空集热管,真空管集热效率高,散热损失小,工作寿命长,国外大量太阳能热电站都采用槽式系统。槽式集热系统是通过抛物面结构将太阳光束聚集到真空管上,加热传热工质,工质可以是水、导热油或熔融盐等。通过跟踪系统与太阳始终保持最佳方向。由于结构原因,槽式系统聚光比一般在50~150     

风电系统的无功功率与电网电压稳定

论述了风电容量在占局部电网相当比例时,风电机组的无功功率调整与电网电压之间的关系,对于定速和变速风电机组的运行特性做了分析,提出了在需要做无功功率调整时风电机组应能满足的特殊要求。     

New energy power generation-wind power generation

This paper introduced the status quo of wind power and wind power generation technology. Focusing on the introduction of wind power generating system ibrational self-consistent field（VSCF）, program implementation included Alternating Current （AC）-Direct Current （DC）-AC conversion system, magnetic field modulation generator system, doubly-fed generator system etc. Among these, doubly-fed generator system is the trend. Where to build the wind farm is very important, so a perfect site is needed. Wind power generation will have a bright future. As long as the wind power can be linked to the grid in large scale.     

Output power control for large wind power penetration in small power system

Nowadays, wind turbine generator (WTG) is increasingly required to provide control capabilities regarding output power. Under this scenario, this paper proposes an output power control of WTG using pitch angle control connected to small power systems. By means of the proposed method, output power control of WTG considering states of power system becomes possible, and in general both conflicting objectives of output power leveling and acquisition power increase are achieved. In this control approach, WTG is given output power command by fuzzy reasoning which has three inputs for average wind speed, variance of wind speed, and absolute average of frequency deviation. Since fuzzy reasoning is used, it is possible to define output power command corresponding to wind speed condition and changing capacity of power system momentarily. Moreover, high performance pitch angle control based on output power command is achieved by generalized predictive control (GPC). The simulation results by using actual detailed model for wind power system show the effectiveness of the proposed method.     

Output power variations with solar power satellites

The first comprehensive evaluation of output power variations expected from Solar Power Satellites is presented. The various factors are classified in a two tier manner as: deterministic (either periodic or non-periodic) and statistical (either constant with system life or changing with life). The largest variations are due to seasonal periodic factors, namely variations in the solar constant (± 3.3 per cent) and a solar illumination variation with the photovoltaic array held perpendicular to the orbit plane (± 4.2 per cent). Other key factors delineated which are being quantified presently include power reductions due to microwave power tube failure and silicon solar cell radiation damage, while multiple shadowing of adjacent power stations in geosynchronous orbit and rectenna structural factors and combining efficiency variations are representative of areas that need further study.     

Microthermophotovoltaic power generator with high power density

A promising energy source for portable MEMS devices, microthermophotovoltaic (micro-TPV) power generator, is described in this paper. The system mainly consists of a micro SiC combustor, and a GaSb photovoltaic (PV) cell array and a simple nine-layer dielectric filter, with a volume of about 3.1 cm³. When the flow rate of H₂ is 4.2 g/h, and H₂/O₂ ratio is 0.7, the system is able to deliver 3.06 W electrical power, the open-circuit voltage and short-circuit current are 2.31 V and 1.74 A, respectively, the result is a power density of about 1.0 W/cm³ (1 MW/m³). The effect of all kinds of factors on the performance of the micro-TPV system is also discussed in this paper.     

A hybrid power source for pulse power applications

Portable 12 V power supplies are used extensively for communications and power tool applications. These devices demand fast response times of the power supply. Fuel cells are generally best suited to continuous power applications and require an initial warm-up period, although they offer the prospect of increased operational duration over a battery for a given weight of portable system. This paper investigates the combination of specific energy performance from the fuel cell system with the specific power and response time of the battery. Two separate hybrid systems have been developed and tested; a planar, 20-cell, polymer electrolyte membrane fuel cell (PEMFC) stack together with either a lead–acid or nickel/cadmium battery; and a conventional 20-cell, bipolar, PEMFC stack. Both systems have been tested under pulse-load conditions at temperatures between −20°C and +40°C, and for comparison, the individual components have undergone similar tests. The hybrid systems have successfully operated continuously for several weeks under load profiles that the fuel cell alone could not sustain.     

Wind power and market power in competitive markets

Average market prices for intermittent generation technologies are lower than for conventional generation. This has a technical reason but can be exaggerated in the presence of market power. When there is much wind smaller amounts of conventional generation technologies are required, and prices are lower, while at times of little wind prices are higher. This effect reflects the value of different generation technologies to the system. But under conditions of market power, conventional generators with market power can further depress the prices if they have to buy back energy at times of large wind output and can increase prices if they have to sell additional power at times of little wind output. This greatly exaggerates the effect. Forward contracting does not reduce the effect. An important consequence is that allowing market power profit margins as a support mechanism for generation capacity investment is not a technologically neutral policy.     

Got power? [power engineers recruitment]

This paper discusses the different factors that can help to ensure that the future demand for power engineers will be met. These factors include the articulation of a compelling mission, development of a comprehensive strategy, execution of supporting tactics, and demonstration of leadership.