Spire wins more funds to develop PV manufacturability

Bedford, Massachusetts-based Spire Corporation has been awarded a $5.2 million cost-shared contract from the Department of Energy’s National Renewable Energy Laboratory in Colorado, to develop automated manufacturing processes for fabricating Solar Brightfield™ large-scale solar electric modules.This is a short news story only. Visit www.re-focus.net for the latest renewable energy industry news     

Restructuring needed to exploit market opportunities

Buoyant forecasts of market growth in excess of 10% for most applications reflected the positive mood of delegates at the Gorham/Intertech ‘Compound Semiconductor Outlook '99’ conference. To fully exploit these opportunities, however, the industry was told it will need to consider its business structure and beware of growing competitors, such as SiGe.     

PV module energy rating: opportunities and limitations

This article sheds new light on photovoltaic (PV) module rating according to predicted yield rather than power measured at standard testing conditions (STC). We calculate module performance ratios (MPR) for measured characteristics of eight different module types and compare them with a reference MPR calculated with typical crystalline silicon characteristics. In place of the not yet existing standardized weather data, we use commercially available weather data for three different locations. The reference MPR for the three locations were 95.5%, 94.6%, and 91.0%, respectively, with differences to the other module types of ±8% at maximum. MPR was calculated with reference to nominal power, and—following IEC 61853—without consideration of potential degradation. The strongest contribution to the initial differences between the module types was due to differences in irradiance dependency. Standard uncertainties for all initial MPR values were calculated and range from 1.8% to 3.0%, including STC power uncertainty. We propose a module rating method that indicates whether a module type's performance is significantly above, below, or essentially equal to the reference. The method evaluates the MPR difference between module type and reference, taking uncertainty into account. Significant differences were only found between modules with obviously different characteristics, but not between the crystalline silicon module types under scrutiny. As the uncertainty analysis did not cover degradation and influences due to the use of not standardized weather data, a sensitivity analysis was performed. Long‐term degradation can change the comparative energy rating significantly, whereas the selection of tilt angle and assumptions regarding module operating temperature did not have a strong effect. Copyright © 2015 John Wiley & Sons, Ltd.     

Simple iterative methods to exploit the signal-space diversity

Signal-space diversity is a power- and bandwidth-efficient diversity technique. To exploit the signal-space diversity, joint maximum-likelihood (ML) detection at the receiver is usually needed, where the complexity grows exponentially with the dimension of the lattice. In this letter, we propose a serial concatenated scheme and two simple iterative methods to exploit the signal-space diversity. The simple iterative methods are based on the idea of soft interference cancellation. The first iterative method is based on a vector Gaussian approximation, while the second one is based on a scalar Gaussian approximation. The complexity of the first iterative method grows cubically with the dimension of the lattice, and the simulations show that its performance approaches that of the optimal maximum a posteriori detection method. The complexity of the second iterative method grows linearly with the dimension of the lattice, and the simulations show that when the dimension of the lattice N=32, at bit-error rate =10/sup -5/, the performance gap between the Rayleigh fading channel and the Gaussian channel is only 0.3 dB.     

Comments on `Using cache mechanisms to exploit nonrefreshing DRAM'sfor on-chip memories'

For the original article see ibid., vol.26, no.4, pp.657-61 (Apr. 1991). In the above-titled paper by D.D. Lee and R.H. Katz, a method for eliminating the need for refreshing for DRAM on-chip caches is presented as a new approach. It is pointed out that the commenters in fact introduced this method in a previous paper (Comput. Arch. News, vol.16, no.4, pp. 45-50, Sept. 1988)     

数据挖掘理论和开发方法

介绍了数据挖掘的概念、常用方法、数据挖掘过程 ,阐述了基于数据仓库的DM技术 ,在此基础上举例说明了数据挖掘理论在现实社会中的应用。     

Coupling PV and CAES power plants to transform intermittent PV electricity into a dispatchable electricity source

This study investigates the transformation of photovoltaic (PV) electricity production from an intermittent into a dispatchable source of electricity by coupling PV plants to compressed air energy storage (CAES) gas turbine power plants. Based on historical solar irradiation data for the United States' south western states and actual PV and CAES performance data, we show that the large‐scale adoption of coupled PV–CAES power plants will likely enable peak electricity generation in 2020 at costs equal to or lower than those from natural gas power plants with or without carbon capture and storage systems. Our findings also suggest that given the societal value of reducing carbon dioxide and the sensitivity of conventional generation to rising fossil fuel prices, this competitive crossover point may occur much sooner. Copyright © 2008 John Wiley & Sons, Ltd.     

Using robot mobility to exploit multipath fading - wireless communications in networked robotics

Communication-aware motion control allows mobile networked robots to increase the average communication throughput. We exploit that in a multipath fading channel, robots can measure the SNR and adapt their motion to spend slightly more time at positions where the channel is good. Two new such cross-layer strategies are analyzed and evaluated: periodic stopping, where the stop duration is a function of the SNR, and controlled stopping, where the robot stops when the communication buffer is filling up. It is shown that the expected average channel capacity can be twice as high as when no cross-layer information is utilized. Experimental evaluation of the strategies confirms the theoretical results.     

The Solarex approach to expanding the PV business

Solarex was founded in 1973 to develop photovoltaic products for terrestrial applications. Over the last 24 years, the company has moved from single-crystal silicon technology to polycrystalline silicon and has also developed both single-junction and multi-junction amorphous silicon solar cell technology. Solarex is now starting to produce 8-ft² amorphous silicon tandem modules in a new plant in Virginia and has initiated new programs to develop the grid-connected markets in the USA and overseas. However, the current USA lead in photovoltaics is in jeopardy as government programs in both Japan and Germany are aggressively supporting the development of building integrated photovoltaic systems in those countries. In order to maintain its leadership in photovoltaics, the USA needs to implement a new national initiative to support the development of building integrated photovoltaics. © 1997 John Wiley & Sons, Ltd.     

California college to build 1 MW PV field

Cerro Coso Community College in Ridgecrest, California is developing a 1 MW PV field. The Addington Partnership of Bakersfield is the project architect and designer.Visit www.re-focus.net for the latest renewable energy industry news     

The PV infrastructure: Architecture from houses to highways

Integrating photovoltaics into the built environment presents unique opportunities and challenges. Designers have to mediate between the functional demands of photovoltaics as solar devices and their architectural role as a building material. Photovolt aics are highly modular and will be used in large and small projects; their design will have to be considered at all scales. Solutions to these problems will change, for better or worse, the orientation and focus of the built environment. Will buildings, now mostly indifferent or even hostile to their climate, turn outward, expressing their relationship to the sun, or will the landscape be transformed into a sea of modules, fixed at monotonously optimized angles?     

WLAN从何处淘金?

WLAN热点技术在近两年的中国刮起了不小的建设旋风,特别是几大电信运营商的追捧,使该产业得到了快速的成长。网通、电信的固定网络的WLAN延伸,中国移动GPRS+WLAN以及中国联通CDMA 1X+WLAN模式的推出,使WLAN技术的应用呈现异常繁荣的景象。但透过火热的市场表象,有业内人士指出,WLAN的运营模式还不成熟,其盈利方式还存在障碍。尽管如此,WLAN的应用仍将快步前进,特别是一些产业巨头对其进行的新探索,也给它的未来发展带来了新的理念。     

三网融合：全球成势前景可期

7月1日,国务院办公厅印发了第一批三网融合试点地区（城市）名单,共计12个城市入围本次试点。该试点城市名单正式出炉,吸引了业界的关注,电信、广电、IT等方面的专家对三网融合的发展提出了更多的设想。业界虽然对三网融合试点工作持支持态度。但也对三网融合行业管制、市场准入限制、业务融合的有效模式等心存疑虑。本文将阐述包括中国在内的全球兰网融合市场发展状况,未来的发展前景及当前面对的挑战。     

Design Strategy to Optimize the Reliability of Grid-Connected PV Systems

This paper presents a strategy, based on the design-of-experiments technique, aimed at optimizing the reliability in inverters for photovoltaic systems. The process involves designing the inverter several times, each time with different specifications, and calculating the reliability for each design. The specifications are established in a systematic manner, in such a way that the parameters with the highest impact are easily identified. The optimization procedure follows a standard reliability estimation methodology and involves modifying the stress factors in a judicious manner. The strategy is exemplified with an integrated boost inverter and a desired mean time between failures of 12 years.