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[en] Highlights: • Case study for 316 climate station conditions was carried out. • Strong linear dependence on total yearly DNI was found. • Simplified model shows accurate results in 12 latitudes worldwide. - Abstract: This paper proposes a simple method for estimating annual thermal performance of parabolic trough collectors (PTCs) based on a linear relation with annual DNI for a certain latitude. A case study with simulations for a novel concentrating solar collector in 316 locations for three operating temperature scenarios worldwide was carried out and showed promising results for the latitudes and continents investigated. For a certain latitude and mean operating temperature, the annual yield of a PTC was found to be linearly proportional to yearly DNI. The proposed method will serve as a simplified alternative to the steady-state and quasi-dynamic methods already used. Estimating performance based on yearly DNI can be used by design engineers to do quick preliminary planning of solar plants. Customers can also use this method to evaluate existing solar collector installations. A TRNSYS/TRNSED tool that uses a steady-state model has been developed to carry out the simulations and it has been validated against a PTC array at Technical University of Denmark (DTU). The results show that the simplified method can give reliable estimates of long-term performance of parabolic trough collectors.
[en] Technology roadmapping is a needs-driven technology planning process to help identify, select, and develop technology alternatives to satisfy a set of market needs. The DOE's Office of Power Technologies' Concentrating Solar Power (CSP) Program recently sponsored a technology roadmapping workshop for parabolic trough technology. The workshop was attended by an impressive cross section of industry and research experts. The goals of the workshop were to evaluate the market potential for trough power projects, develop a better understanding of the current state of the technology, and to develop a conceptual plan for advancing the state of parabolic trough technology. This report documents and extends the roadmap that was conceptually developed during the workshop
[en] A vertical light ray coming from infinity is reflected by a primary parabolic mirror M1 having focus at F1. At a small distance from F1 a secondary mirror M2, symmetric with respect to the vertical axis, is placed. One would like to find the analytic equation of the mirror M2, so that all rays from infinity, incident on M1, could be sent back to the vertex V1 of the primary mirror M1. We denote the mirror M2 with the name of zozzaroid, after P Zozzaro, who first proposed the problem. Recalling the famous legend about Dionysius ear, we find that M2 has either an elliptic or a hyperbolic profile.
[en] A transmission pipe transmits laser beams along an axis thereof, and is inserted at the top end to a pipeline to be fabricated. A flat mirror is secured to the top end of the transmission pipe, and laser beams are reflected by the mirror, passed through a fabrication nozzle and focused to a fabrication point in the pipeline to be fabricated. A lens-type light focusing system is guided to the fabrication point by a plurality of rollers rotatable in the axial direction disposed in circumferential direction each at an equal pitch at the outer circumference of the transmission pipe. A centering mechanism is disposed for keeping the transmission pipe coaxially with the pipeline to be fabricated. Further, there are also disposed a mirror-type light focusing optical system for focusing light by a paraboloidal mirror and a spherical vehicle rotatable in all directions. A laser fabrication device can be reduced in the size, and it can be used in a high temperature and highly radioactive circumstance. (N.H.)
[en] The paper is devoted to searching the optimal location of first collecting mirror in the extreme ultraviolet radiation plasma sources. It is shown that the system efficiency can be increased by 1.5...2.5 times in the case of elliptical plasma radiation pattern and the optimal location of the first collecting mirror. In this case the first collecting mirror should cover the plasma on lateral side
[en] Parabolic solar energy cooker was designed using locally available materials such as pieces of iron and plane mirrors. The diameter of the dish was 12 x 10-3 mm and pieces of glass mirrors were adhered to its concave surface using abro silicon gum as solar energy reflectors. The solar cooker was used to cook different food materials such as rice, bean, yam and stew between 11am and 3pm. The time taken to cook the food materials were measured and compared to the time it takes to cook similar food samples of the same quantity using kerosene and electric stove. It took the kerosene and electric stoves two hours, forty minutes (2.40) and two hours, ten minutes (2.10) respectively to cook beans with all the ingredients while the fabricated solar cooker took only one hour fifteen minutes. Due to high solar energy absorption capacity of the solar cooker and insolation rate, the study has reveled that it is faster, safer and takes less time to cook using cooker than either kerosene or electric stove.