Thermal performance study of a parabolic trough collectoer based on heat transfer oil

2013 ◽  
Author(s):  
Yaxuan Xiong ◽  
Chongfang Ma ◽  
Yuting Wu ◽  
Hong He
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Performance Study ◽  
Parabolic Trough

Exergy Control for a Flat-Plate Collector/Rankine Cycle Solar Power System

1991 ◽  
Vol 113 (2) ◽  
pp. 89-93 ◽  
Author(s):  
Giampaolo Manfrida ◽  
Shukuru J. M. Kawambwa
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Thermal Performance ◽  
Saturated Vapor ◽  
Rankine Cycle ◽  
Pressure Level ◽  
Heat Transfer Fluid ◽  
Second Law ◽  
Operating Pressure ◽  
Performance Study

A performance study is presented of a Rankine organic cycle powered by a low temperature solar collector. In this work a two-phase collector is considered where the heat transfer fluid is vaporized and its saturated vapor expands in a turbine according to a Rankine cycle. The collector system is divided into a boiling and a nonboiling (subcooled) part: The limit between the two depends upon the value of flow rate and radiation. A modified form of the Bliss equation is used to model the thermal performance of the collector in terms of thermal efficiency versus DTI [DTI= (Absorber average temperature-Ambient temperature)/ Solar Radiation]. The system is analyzed by second-law analysis, and it includes several exergy losses of different types (heat transfer, heat loss, etc.) which determine the overall exergy balance. Different working fluids are considered, and optimization to a certain extent is demonstrated from this point of view. In order to minimize irreversibilities and guarantee the most efficient conversion processes, the most important point is the right selection of the collector operating pressure level, which depends on the instantaneous value of radiation and ambient temperature (as well as on the collector thermal performance). The choice of the optimal pressure level is done by means of second-law arguments; the flow rates across the collector, the turbine, and the condenser are consequently determined. A simulation over a typical sunny day in Florence, Italy allows the calculation of the expected daily performance.

Analysis of Electric Performance and Optimization of Trough Concentrating Solar Thermoelectric Cogeneration System

2013 ◽  
Vol 368-370 ◽  
pp. 1209-1213
Author(s):  
Zhi Ping Chen ◽  
Ming Li ◽  
Xu Ji ◽  
Xi Luo
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Performance Optimization ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Transfer Model ◽  
Experimental Basis ◽  
Parabolic Trough ◽  
One Dimensional ◽  
Cogeneration System

This study introduced the basic situation of the parabolic trough concentrating solar cogeneration system, and set a one-dimensional steady-state mathematical heat transfer model based on the experimental devices, at the same time clarified influencing factors of the major heat transfer process and thermal performance of the system. The article did perspectives theoretical analysis and simulation for the system in different aspects, through using of solar trough concentrator reflecting device, established thermal performance experiments that water as the working fluid flow, provided theoretical and experimental basis for the thermal performance optimization of the system.

Thermal Performance of a Receiver Tube for a High Concentration Ratio Parabolic Trough System and Potential for Improved Performance With Syltherm800-CuO Nanofluid

2015 ◽  
Author(s):  
Aggrey Mwesigye ◽  
Zhongjie Huan ◽  
Josua P. Meyer
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Concentration Ratio ◽  
Low Flow ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
High Concentration ◽  
Flow Rates

In this paper, the thermal performance of a high concentration ratio parabolic trough system and the potential for improved thermal performance using Syltherm800-CuO nanofluid were investigated and presented. The parabolic trough system considered in this study has a concentration ratio of 113 compared with 82 in current commercial systems. The heat transfer fluid temperature was varied between 350 K and 650 K and volume fractions of nanoparticle were in the range 1–6%. Monte-Carlo ray tracing was used to obtain the actual heat flux on the receiver’s absorber tube. The obtained heat flux profiles were subsequently coupled with a computational fluid dynamics tool to investigate the thermal performance of the receiver. From the study, the results show that with increased concentration ratios, receiver thermal performance degrades, with both the receiver heat loss and the absorber tube circumferential temperature differences increasing, especially at low flow rates. The results further show that the use of nanofluids significantly improves receiver thermal performance. The heat transfer performance increases up to 38% while the thermal efficiency increases up to 15%. Significant improvements in receiver thermal efficiency exist at high inlet temperatures and low flow rates.

Olive Leaf-Synthesized Nanofluids for Solar Parabolic Trough Collector—Thermal Performance Evaluation

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Eric C. Okonkwo ◽  
Edidiong A. Essien ◽  
Doga Kavaz ◽  
Muhammad Abid ◽  
Tahir A. H. Ratlamwala
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Thermal Performance ◽  
Olive Leaf ◽  
Parabolic Trough ◽  
Leaf Extracts ◽  
Comparison Of The Results

This study presents a novel performance evaluation of the commercially available LS-2 collector operating with an oil-based olive leaf-synthesized nanofluid. The nanoparticles were synthesized experimentally from olive leaf extracts (OLEs): OLE-ZVI and OLE-TiO2. The thermophysical properties of the nanoparticles were then added to Syltherm-800 thermal oil, and its performance on the parabolic trough solar collector (PTC) was evaluated numerically. The PTC under study was modeled on the engineering equation solver (EES) and validated thermally with results found in the literature. The synthesized nanoparticles were also found to possess anticorrosion properties, nontoxic, and less expensive to produce when compared to commercially available ones. The use of the nanofluids (Syltherm-800/OLE-ZVI and Syltherm-800/OLE-TiO2) was evaluated against the parameters of thermal and exergetic efficiencies, heat transfer coefficient, thermal losses, and pressure drop. The study shows that an enhancement in thermal performance of 0.51% and 0.48% was achieved by using Syltherm-800/OLE-ZVI and Syltherm-800/OLE-TiO2 nanofluids, respectively. A heat transfer coefficient enhancement of 42.9% and 51.2% was also observed for Syltherm-800/OLE-TiO2 and Syltherm-800/OLE-ZVI nanofluids, respectively. Also, a mean variation in pressure drop of 11.5% was observed by using the nanofluids at a nanoparticle volumetric concentration of 3%. A comparison of the results of this study with related literature shows that the proposed nanofluids outperform those found in literature.

Computational Analysis of Thermal Performance and Entropy Generation of Nanofluid Flow in Microchannels

2012 ◽  
Author(s):  
Jie Li ◽  
Clement Kleinstreuer ◽  
Yu Feng
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Thermal Performance ◽  
Computational Study ◽  
Heat Removal ◽  
Local Heat Transfer ◽  
Design Tool ◽  
Performance Study ◽  
Operational Parameters ◽  
Nanofluid Flow

High heat loads of mechanical, chemical, and biomedical microsystems require heat exchangers which are very small, robust, and efficient. Nanofluids are dilute suspensions of nanoparticles in liquids, which may exhibit remarkable heat transfer characteristics, especially for heat removal in micro-devices. Minimization of entropy generation is potentially a design tool to determine best heat exchanger device geometry and operation. Focusing on microchannel heat sink applications, the thermal performance of pure fluid flow as well as different nanofluids (i.e., Al2O3+water and ZnO+EG) with different volume fractions are discussed. The local and volumetric entropy rates caused by frictional and thermal effects are illustrated for different coolants, geometries and operational parameters. The Feng-Kleinstreuer (F-K) thermal conductivity model, which consists of a base-fluid static part, kbf, and a new “micro-mixing” part, kmm, i.e., knf = kbf + kmm, was adopted in the thermal performance study of nanofluid flow in microchannels. In addition, two effective nanofluid viscosity models have been analyzed and are compared in the current study. In summary, the friction factor, pressure gradient, pumping power, local heat transfer coefficient, thermal resistance and entropy generation are evaluated for different nanofluids. The experimentally validated computational study provides new physical insight and criteria for design applications towards effective micro-system cooling.

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