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Sun H.,Tsinghua University | Gong B.,CAS Institute of Electrical Engineering | Yao Q.,Tsinghua University
Renewable and Sustainable Energy Reviews | Year: 2014

This article reviews existing papers and presents considerations about wind loads on heliostats and trough collectors. Research efforts all over the world have focused, for decades, on the evaluation and reduction of wind loads on heliostats and trough collectors. However, the subject continues to be a live issue, since scientists are attempting to find a low-cost and highly accurate solution. In this paper, we will review the effects of wind loads on heliostats and trough collectors, considering wind flow characteristics, turbulence intensity and the Reynolds number, the aspect ratio, porosity and mirror gap, wind loads on isolated collectors and on collector fields, and the effects of wind on beam quality. This review is expected to be of use to researchers and engineers involved in the analysis and design of heliostats and trough collectors. © 2014 Elsevier Ltd.

Ma Y.,CAS Institute of Electrical Engineering
Superconductor Science and Technology | Year: 2012

Iron-based superconductors, with T c values up to 55K, are of great interest for applications, due to their lower anisotropies and ultrahigh upper critical fields. In the past four years, great progress has been made in the fabrication of iron-based superconducting wires and tapes using the powder-in-tube (PIT) processing method, including main three types of 122, 11, and 1111 iron-based parent compounds. In this article, an overview of the current state of development of iron-based superconducting wires and tapes is presented. We focus on the fabrication techniques used for 122 pnictide wires and tapes, with an emphasis on their meeting the critical current requirements for making high-performance conductors, such as a combination of using Ag sheath, addition element and optimized heat treatment to realize high J c, ex situ process employed to reduce non-superconducting phases and to obtain a high relative density, and a texture control to improve grain connectivity. Of particular interest is that so far transport J c values above 10 4Acm 2 at 4.2K and 10 T are obtained in 122 type tapes, suggesting that they are prospective candidates for high-field applications. Finally, a perspective and future development of PIT pnictide wires are also given. © 2012 IOP Publishing Ltd.

Wang Z.,CAS Institute of Electrical Engineering
Energy | Year: 2010

China's total installed electrical power capacity reached 700. GW by the end of 2007 and is predicted to surpass 900. GW in 2010. The rapid increase in energy demand and increasing global warming have both pushed China to change its current electrical power structure where coal power accounts for nearly 75% of the total electric power generation. China has already become the world's largest solar water heater producer and user. However, there is still much to be done in the solar thermal power field before its commercialization. Solar thermal power technologies including solar power towers, solar parabolic trough concentrators, solar dish/stirling systems, linear Fresnel reflectors, and solar chimneys have been studied in China since the 1980s. A 10. kW dish/stirling project was funded by the Ministry of Science and Technology (MOST) during 2000-2005 with a 1. MW solar power tower and research of trough concentrator metal-glass evacuated tubes supported during 2006-2010. This paper describes a continued solar thermal power development roadmap in China in 5-year intervals between 2006 and 2025. © 2009 Elsevier Ltd.

Bai F.,CAS Institute of Electrical Engineering
International Journal of Thermal Sciences | Year: 2010

Using air as heat transfer fluid for electricity generation offers some significant advantages for the development of Concentrated Solar Power (CSP): high conversion efficiency, low environmental impact and being used in deserts or other areas scarce of water resources. Silicon carbide ceramic foams have the characteristics of light weight, high strength, large specific surface areas, high porosity and excellent thermal shock resistance performance which make them particularly fit for absorber material in CSP. In this paper, thermal performance of silicon carbide ceramic foam as solar air receiver is investigated analytically based on the one dimensional physical model. The analytical results show that the air flow resistance increases obviously with increasing air outlet temperature, the air flow resistance while the air outlet temperature is equal to 1000 °C is nearly 3 times the one while the air outlet temperature is equal to 20 °C with air velocity range is between one and six meters per second. The results of one dimensional analysis of flow and heat transfer process of ceramic foams suggest that there exists an input solar energy flux limit for the unpressurized system, which will lead to limit the power capacity and the outlet air temperature enhancement. © 2010 Elsevier Masson SAS. All rights reserved.

CAS Institute of Electrical Engineering | Date: 2013-08-19

A superconducting magnet system for head imaging is disclosed which includes a cryocooler, a high-pressure helium container, a self-excitation heat pipe and a superconducting magnet. A second stage coldhead of the cryocooler is connected to the high-pressure helium container for converting the helium gas in the high-pressure helium container into liquid helium. The self-excitation heat pipe forms a closed cooling loop, and liquid helium in the high-pressure helium container flows circularly in the self-excitation heat pipe. The self-excitation heat pipe cools the superconducting magnet, wherein part of the liquid helium in the self-excitation heat pipe is converted into the helium gas due to the heat disturbance generated by the superconducting magnet, and the helium gas interacts with the liquid helium to generate liquid helium vibration.

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