Enhanced Solar Energy Harvest for Power Generation From Brayton Cycle

Author(s):  
Matthew Neber ◽  
Hohyun Lee

A scalable and modular solar thermal dish-Brayton system is proposed in response to growing demand for renewable energy and distributed power generation. Existing dish systems require large areas to achieve sufficient conversion efficiency for the cost of the system. Also, the conversion efficiencies are limited by the materials and manufacturing processes. This paper proposes a low cost, high efficiency solar absorber as the core of a dish-Brayton system with the capability to achieve much higher operating temperatures than current absorbers. A simple cylindrical part, forming a black body cavity, is fabricated from silicon carbide for high absorptivity at a low fabrication cost. The manufacturing process consists of a simple casting and sintering procedure, which is a common way of creating ceramic parts. Another cylindrical shell is fabricated to cover the outer surface of the black body cavity, creating a channel for air to pass through. The high thermal conductivity of the silicon carbide ensures the efficient heat transfer between the solar absorber and the air. The entire solar energy absorber is designed to heat air up to 1500 K, which would improve energy conversion efficiency of concentrated solar power generation based on 1270 K by 20%. Analysis and test results on a scaled device are presented.

2020 ◽  
Vol 13 (2) ◽  
pp. 579-591 ◽  
Author(s):  
Binbin Jiang ◽  
Xixi Liu ◽  
Qi Wang ◽  
Juan Cui ◽  
Baohai Jia ◽  
...  

A high conversion efficiency of 11.2% was realized in a low-cost PbS-based segmented thermoelectric module.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1579
Author(s):  
Heng Zhang ◽  
Na Wang ◽  
Kai Liang ◽  
Yang Liu ◽  
Haiping Chen

A solar-aided power generation (SAPG) system effectively promotes the high efficiency and low cost utilization of solar energy. In this paper, the SAPG system is represented by conventional coal-fired units and an annular Fresnel solar concentrator (AFSC) system. The annular Fresnel solar concentrator system is adopted to generate solar steam to replace the extraction steam of the turbine. According to the steam–water matrix equation and improved Flugel formula, the variable conditions simulation and analysis of the thermo-economic index were proposed by Matlab. Furthermore, in order to obtain the range of small disturbance, the method of partial replacement is used, that is, the extraction steam of the turbine is replaced from 0 to 100% with a step size of 20%. In this work, a SAPG system is proposed and its thermo-economic index and small disturbance scope are analyzed. The results show that the SAPG system is energy-saving, and the application scope of small disturbance is related to the quantity of the extraction steam and evaluation index.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Guiming Peng ◽  
Xueqing Xu ◽  
Gang Xu

The ramping solar energy to electricity conversion efficiencies of hybrid organic-inorganic perovskite solar cells during the last five years have opened new doors to low-cost solar energy. The record power conversion efficiency has climbed to 19.3% in August 2014 and then jumped to 20.1% in November. In this review, the main achievements for perovskite solar cells categorized from a viewpoint of device structure are overviewed. The challenges and prospects for future development of this field are also briefly presented.


Author(s):  
Salah Obayya ◽  
Nihal Fayez Fahmy Areed ◽  
Mohamed Farhat O. Hameed ◽  
Mohamed Hussein Abdelrazik

The solar energy is able to supply humanity energy for almost another 1 billion years. Optical nano-antennas (ONAs) are an attractive technology for high efficiency, and low-cost solar cells. These devices can be classified to semiconductor nano-wires and metallic nano-antenna. Extensive studies have been carried out on ONAs to investigate their ability to harvest solar energy. Inspired by these studies, the scope of the chapter is to highlight the latest designs of the two main types of ONAs. The metallic nano-antennas are discussed based on the following points: plasmon, modeling, and performance of antenna designs using different configurations and materials. Moreover, the semiconductor nano-wires are studied thoroughly in terms of photonic crystals, antenna design with different patterns, nano-wire forms and materials. Also, the applications of ONAs and their fabrication aspects such as diode challenges are presented in detail. Finally, three novel designs of ONAs are presented and numerically simulated to maximize the harvesting efficiency.


2015 ◽  
Vol 730 ◽  
pp. 173-177
Author(s):  
Yu Wen Tang

Solar energy is an inexhaustible and renewable energy without environmental pollution. Solar energy can be used in three kinds of forms: solar thermal energy, photochemical conversion and photovoltaic power generation. Among these, the final form of photovoltaic power generation is electricity which can be transported, applied and stored conveniently. On the basis of photovoltaic effect, solar cell is developed as a new technology to convert light energy into electrical energy using semiconductor. Up to now the two key problems of the development of solar cells are how to improve the conversion efficiency and reduce cost. Therefore, the material and production technology used for solar cells are discussed based on improving conversion efficiency in this article.


2019 ◽  
Vol 7 (36) ◽  
pp. 20494-20518 ◽  
Author(s):  
Bo Li ◽  
Lin Fu ◽  
Shuang Li ◽  
Hui Li ◽  
Lu Pan ◽  
...  

High-efficiency and low-cost perovskite solar cells (PSCs) are desirable candidates for addressing the scalability challenge of renewable solar energy.


2014 ◽  
Vol 953-954 ◽  
pp. 83-86 ◽  
Author(s):  
Lin Jun Wang ◽  
Li Xiao Xu ◽  
Jing Men ◽  
Dong Zhang ◽  
Zhang Wei Gao ◽  
...  

Solar energy is a kind of clean and green energy, its use can reduce the dual pressure of resources and environmental pollution. Firstly, this paper introduces groove, tower and dish type solar thermal power generation system. Then it introduces the components of dish-stirling system and the principle and features of stirling engine. The system has simple structure, reliable operation, high efficiency, low noise, low cost of power generation and good commercial prospects. But for some key parts of system, there are many problems that need to be solved. The main research of dish-stirling system is to optimize the key parts of system and reduce the system costs.


2014 ◽  
Author(s):  
Abhishek Wadhwa ◽  
Sung-Yong Park

We present optical analyses of a microfluidic tunable liquid prism to find its optimized configuration that can achieve wider beam steering as well as less reflection loss and eventually maximize solar energy capture without mechanical tracking. For this study, four different prism configurations are compared from single to quad-stacked ones with various refractive indices of the liquids filled in the prism. Its beam steering capability can be improved by increasing the refractive index ratio between the liquids used and by using higher number of the stacked prisms. The quad-stacked prism is able to steer incoming sunlight with an incident angle of a α ≤ ± 75° at an apex angle of φ ≤ ± 30°, which represents more than 5 times improvement, when it is compared to the single prism using the same liquids. For appropriate liquid material selection, the effect of refractive index ratio, r = n2/n1, on beam steering was additionally studied. However, one considerable issue is the fact that the better beam steering, the more reflection loss. This is because both higher number of interfaces and larger refractive index ratio make more reflection at each of the interfaces. Our reflectance analysis showed that the quad prism performs inferior to the double prism until α = ± 32°, while being of superior beam steering performance. To further reduce the solar energy loss through the quad prism, a modified configuration is proposed with a thin film added to the interfaces. 50 % of the total reflection was reduced. Our technology promises an alternative to a low-cost and high-efficiency solar tracking system capable of beam steering as wide as ± 75° and reflection loss as low as 4.5%, during all daily tracking of the sun.


2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Jui-Yung Chang ◽  
Hao Wang ◽  
Liping Wang

The present study focuses on nanowire-based metamaterials selective solar absorbers. Finite-difference time-domain (FDTD) simulation is employed for numerically designing a broadband solar absorber made of lossy tungsten nanowires which exhibit spectral selectivity due to the excitation of magnetic polariton (MP). An inductor–capacitor circuit model of the nanowire array is developed in order to predict the resonance wavelengths of the MP harmonic modes. The effects of geometric parameters such as nanowire diameter, height, and array period are investigated and understood by the sweep of geometric parameters, which tunes the MP resonance and the resulting optical and radiative properties. In addition, the optical properties and conversion efficiency of this nanowire-based absorber are both demonstrated to be insensitive on incidence angles, which illustrates the potential applicability of the proposed nanowire-based metamaterial as a high-efficiency wide-angle selective solar absorber. The results show that the nanowire-based selective solar absorber with base geometric parameters can reach 83.6% of conversion efficiency with low independence of incident angle. The results will facilitate the design of novel low-cost and high-efficiency materials for enhancing solar thermal energy harvesting and conversion.


Author(s):  
Virginie Vaubert ◽  
David P. Stinton ◽  
Chris Barra ◽  
Santosh Limaye

Advanced, coal-fueled, power generation systems utilizing pressurized fluidized bed combustion (PFBC) and integrated gasification combined cycle (IGCC) technologies are currently being developed for high-efficiency, low emissions, and low-cost power generation. In spite of the advantages of these promising technologies, the severe operating environment often leads to material degradation and loss of performance in the barrier filters used for particle entrapment. To address this problem, LoTEC Inc., and Oak Ridge National Laboratory are jointly designing and developing a monolithic cross-flow ceramic hot-gas filter. The filter concept involves a truly monolithic cross-flow design that is resistant to delamination, can be easily fabricated, and offers flexibility of geometry and material make-up. During Phase I of the program, a thermo-mechanical analysis was performed to determine how a cross-flow filter would respond both thermally and mechanically to a series of thermal and mechanical loads. The cross-flow filter mold was designed accordingly, and the materials selection was narrowed down to Ca0.5Sr0.5Zr4P6O24 (CS-50) and 2Al2O3−3SiO2 (mullite). A fabrication process was developed using gelcasting technology and monolithic cross-flow filters were fabricated. The program focuses on obtaining optimum filter permeability and testing the corrosion resistance of the candidate materials.


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