A computationally efficient TLM thermal model in the beam displacement modulation regime

2012 ◽  
Vol 43 (9) ◽  
pp. 649-655
Author(s):  
Mateusz Kosikowski ◽  
Zbigniew Suszyński
2019 ◽  
Vol 166 (13) ◽  
pp. A3059-A3071 ◽  
Author(s):  
Ngoc Tham Tran ◽  
Troy Farrell ◽  
Mahinda Vilathgamuwa ◽  
San Shing Choi ◽  
Yang Li

Author(s):  
Jacob A. Kerkhoff ◽  
Michael J. Wagner

Abstract This paper presents advances to a thermal model for a cavity-type receiver that will be integrated into NREL’s System Advisor Model (SAM) software. Traditional concentrated solar power towers make use of an external cylindrical receiver where all active surfaces are fully exposed to the environment, resulting in significant convective and radiative losses. Cavity-type receivers promise to mitigate these losses by instead accepting solar flux through an aperture. In order to allow detailed resolution of the temperature distribution across the cavity, it is necessary to create refined meshes for different cavity geometries and determine the view factor accurately and quickly between any two elements in the mesh. To accomplish this, an analytical function is written to precisely calculate view factors between arbitrary planar polygons without requiring the use of computationally expensive Monte Carlo ray tracing. These view factors are modified using the F-hat method and used as the basis for a two-band radiation heat transfer model. Heat transfer fluid routing is handled through an elemental connectivity matrix, which specifies the elemental fluid temperature variation from inlet to outlet and allows the cavity mesh to interact with the fluid elements. The model is solved iteratively for panel and then fluid temperatures in order to account simultaneously for all energy transfers (convective, long wavelength, short wavelength, and fluid). This approach offers a computationally efficient but still detailed simulation of cavity receiver configurations making it suitable for use in an annual-hourly time series simulation tool such as SAM.


1989 ◽  
Vol 50 (C2) ◽  
pp. C2-237-C2-243 ◽  
Author(s):  
H. VOIT ◽  
E. NIESCHLER ◽  
B. NEES ◽  
R. SCHMIDT ◽  
CH. SCHOPPMANN ◽  
...  

2020 ◽  
Author(s):  
E Bori ◽  
A Navacchia ◽  
L Wang ◽  
L Duxbury ◽  
S McGuan ◽  
...  

Author(s):  
B. Aparna ◽  
S. Madhavi ◽  
G. Mounika ◽  
P. Avinash ◽  
S. Chakravarthi

We propose a new design for large-scale multimedia content protection systems. Our design leverages cloud infrastructures to provide cost efficiency, rapid deployment, scalability, and elasticity to accommodate varying workloads. The proposed system can be used to protect different multimedia content types, including videos, images, audio clips, songs, and music clips. The system can be deployed on private and/or public clouds. Our system has two novel components: (i) method to create signatures of videos, and (ii) distributed matching engine for multimedia objects. The signature method creates robust and representative signatures of videos that capture the depth signals in these videos and it is computationally efficient to compute and compare as well as it requires small storage. The distributed matching engine achieves high scalability and it is designed to support different multimedia objects. We implemented the proposed system and deployed it on two clouds: Amazon cloud and our private cloud. Our experiments with more than 11,000 videos and 1 million images show the high accuracy and scalability of the proposed system. In addition, we compared our system to the protection system used by YouTube and our results show that the YouTube protection system fails to detect most copies of videos, while our system detects more than 98% of them.


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