scholarly journals Sensitive Analysis for the Efficiency of a Parabolic Trough Solar Collector Based on Orthogonal Experiment

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoyan Liu ◽  
Jing Huang ◽  
Qianjun Mao
Keyword(s):  
Thermal Efficiency ◽  
Solar Collector ◽  
Orthogonal Experiment ◽  
Cold Climate ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Parabolic Trough ◽  
Pipe Length ◽  
Climate Region ◽  
Parabolic Trough Solar Collector

A multitude of the researches focus on the factors of the thermal efficiency of a parabolic trough solar collector, that is, the optical-thermal efficiency. However, it is limited to a single or double factors for available system. The aim of this paper is to investigate the multifactors effect on the system’s efficiency in cold climate region. Taking climatic performance into account, an average outlet temperature of LS-2 collector has been simulated successfully by coupling SolTrace software with CFD software. Effects of different factors on instantaneous efficiency have been determined by orthogonal experiment and single factor experiment. After that, the influence degree of different factors on the collector instantaneous efficiency is obtained clearly. The results show that the order of effect extent for average maximal deviation of each factor is inlet temperature, solar radiation intensity, diameter, flow rate, condensation area, pipe length, and ambient temperature. The encouraging results will provide a reference for the exploitation and utilization of parabolic trough solar collector in cold climate region.

Influence of Dimensionless Parameter on De-Ionized Water-alumina Nanofluid Based Parabolic Trough Solar Collector

2020 ◽  
Vol 13 (3) ◽  
pp. 206-221
Author(s):  
Vijayan Gopalsamy ◽  
Karunakaran Rajasekaran ◽  
Logesh Kamaraj ◽  
Siva Sivasaravanan ◽  
Metin Kok
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Solar Collector ◽  
Dimensionless Parameter ◽  
Parabolic Trough ◽  
Alumina Nanofluid ◽  
Parabolic Trough Solar Collector

Background: Aqueous-alumina nanofluid was prepared using magnetic stirrer and ultrasonication process. Then, the prepared nanofluid was subjected to flow through the unshielded receiver of the parabolic trough solar collector to investigate the performance of the nanofluid and the effects of the dimensionless parameter were determined. Methods: The experimental work has been divided into two sections. First, the nanofluid was prepared and tested for its morphology, dimensions, and sedimentation using X-Ray Diffraction and Raman shift method. Then, the nanofluids of various concentrations from 0 to 4.0% are used as heat transfer fluid in unshielded type collector. Finally, the effect of the dimensionless parameter on the performance was determined. Results: For the whole test period, depending upon the bulk mean temperature, the dimensionless parameters such as Re and Nu varied from 1098 to 4552 & 19.30 to 46.40 for air and 2150 to 7551 & 11.11 to 48.54 for nanofluid. The enhancement of thermal efficiency found for 0% and 4.0% nanoparticle concentrations was 32.84% for the mass flow rate of 0.02 kg/s and 13.26% for the mass flow rate of 0.06 kg/s. Conclusion: Re and Nu of air depend on air velocity and ambient temperature. Re increased with the mass flow rate and decreased with concentration. Heat loss occurred by convection mode of heat transfer. Heat transfer coefficient and global efficiency increased with increased mass flow rate and volume fraction. The thermal efficiency of both 0% and 4.0% concentrations became equal for increased mass flow rate. It has been proven that at high mass flow rates, the time available to absorb the heat energy from the receiver is insufficient.

Determination of Parabolic Trough Solar Collector Efficiency Using Nanofluid: A Comprehensive Numerical Study

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Hamidreza Khakrah ◽  
Amir Shamloo ◽  
Siamak Kazemzadeh Hannani
Keyword(s):  
Renewable Energy ◽  
Solar Collector ◽  
Volume Fraction ◽  
Numerical Study ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Parabolic Trough ◽  
Metallic Nanoparticle ◽  
Velocity Magnitude ◽  
Parabolic Trough Solar Collector

Due to significant reduction in fossil fuel sources, several researches have been conducted recently to explore modern sources of renewable energy. One of the major fields in the category of renewable energy harnessing devices is parabolic trough solar collector (PTC). Several parameters have effect on the overall efficiency of the PTCs. As the effect of these parameters is coupled to each other, a comprehensive investigation is necessary. In the present study, a numerical analysis is performed to examine the efficiency of PTCs via variation of several governing parameters (e.g., wind velocity magnitude, nanoparticles volume fraction, inlet temperature, and reflector's orientation). A detailed set of absorber, reflector, and protection glass in addition to the surrounding environment is modeled to capture sufficiently accurate data. The working fluid is assumed to be nanofluid to inspect the advantage of metallic nanoparticle addition to the base fluid. The Monte Carlo radiation tracing method is utilized to calculate the solar gain on the absorber tube. According to the obtained results, the efficiencies are reduced by 1–3% by rotating the reflector by 30 deg relative to wind direction. Moreover, 14.3% and 12.4% efficiency enhancement is obtained by addition of 5% volume fraction of Al2O3 to the base synthetic oil for horizontal and rotated reflectors, respectively.

scholarly journals Polynomial Expressions for the Thermal Efficiency of the Parabolic Trough Solar Collector

2020 ◽  
Vol 10 (19) ◽  
pp. 6901
Author(s):  
Evangelos Bellos ◽  
Christos Tzivanidis
Keyword(s):  
Thermal Efficiency ◽  
Solar Collector ◽  
Percentage Error ◽  
Parabolic Trough ◽  
Degree Polynomial ◽  
Unknown Parameters ◽  
Fourth Degree ◽  
Best Fitting ◽  
Difference Term ◽  
Parabolic Trough Solar Collector

The parabolic trough solar collector (PTC) is the most mature solar concentrating technology, and this technology is applied in numerous thermal applications. Usually, the thermal efficiency of the PTC is expressed with the aid of polynomial expressions. However, there is not a universal expression that is applied in all cases with high accuracy. Many studies use expressions with the first-degree polynomial, second-degree, or fourth-degree polynomial expressions. In this direction, this work is a study that investigates different expressions about the thermal efficiency of a PTC with a systematic approach. The LS-2 PTC module is examined with a developed numerical model in the Engineering Equation Solver for different operating temperatures and solar beam irradiation levels. This model is validated using experimental literature data. The found data are approximated with various polynomial expressions with up to six unknown parameters in every case. In every case, the mean absolute percentage error and the R2 are calculated. According to the final results, the use of the third power term leads to the best fitting results, as well as the use of the temperature difference term (ΔΤ), something that is new according to the existing literature. More specifically, the final suggested formula has the following format: “ηcol = a0 + a3∙ΔT3/Gb + b∙ΔΤ”. The results of this work can be used by the scientists for the optimum fitting of the PTC efficiency curves and for applying the best formulas in performance determination studies.

scholarly journals An Investigation of Hybrid Solar-Steam Power Plant: A case study in Iraq

2020 ◽  
Vol 10 (4) ◽  
pp. 199-216
Author(s):  
Dr. Karima Esmail Amori ◽  
Randa Rashid Sari
Keyword(s):  
Power Plant ◽  
Solar Collector ◽  
Thermal Power ◽  
Working Fluid ◽  
Feed Water ◽  
Outlet Temperature ◽  
Parabolic Trough ◽  
Flow Rates ◽  
Parabolic Trough Solar Collector ◽  
Side Flow

 In this work integrating Al-Zubaydia (Kut-Iraq) thermal power plant with solar thermal system is studied for heating feed water by solar energy to reduce fuel consumption and greenhouse gases emission. A closed type Parabolic Trough Solar Collector (PTSC) is designed, constructed, instrumented, and tested. Its thermal characteristics are reported under Iraq climate conditions for the period extended from June, to September 2017. The collector heat gain, efficiency, absorber temperature and heat exchanger effectiveness (considered as feed water heater) were presented for absorber side flow rates of (0.15, 0.2, 0.3, 0.4, 0.5) lpm of water or oil), and shell side water flow rates of (0.4, 0.5, 0.6lpm). Results show that the maximum obtained thermal efficiency of parabolic trough solar collector was 83.33% for oil working fluid. The maximum obtained oil outlet temperature was 106 oC at solar noon for (0.15) lpm. Theoretical results showed that the fuel save mode needs collector area of (32842 m2), while that needed for power boosting is (102569 m2) for the same thermal cycle efficiency. The fuel save mode reported a reduction in greenhouse emission.

scholarly journals THERMAL PERFORMANCE OF PARABOLIC TROUGH SOLAR COLLECTOR

2018 ◽  
Vol 18 (3) ◽  
pp. 389-404
Author(s):  
Karima E Amori ◽  
Randa R Sari
Keyword(s):  
Solar Collector ◽  
Tracking System ◽  
Outlet Temperature ◽  
Parabolic Trough ◽  
Heat Gain ◽  
Flow Rates ◽  
Climate Conditions ◽  
Mass Flow Rates ◽  
Parabolic Trough Solar Collector ◽  
System Water

 This work presents design, instrumented and test of a parabolic trough solar collectorunder Baghdad climate conditions (of latitude 33.33o N, of longitude 44.4oE). The parabolictrough solar collector consists of: a mirror matrix or tapes which work as reflective surfaceof (2m *1m), absorber copper tube (receiver), two axis tracking system. Water is used as aheat transfer medium. The setup is tested within clear days from June, to September 2017.The collector heat gain, efficacy and temperature of absorber were presented for absorberfive different circulating mass flow rates of (0.15, 0.2, 0.3, 0.4, 0.5) 1pm. The results showthat the maximum thermal efficiency of the parabolic trough solar collector is 80.26%. Themaximum outlet temperature of the absorber tube reaches 81 oC at the noon when waterflows at (0.15) 1pm. The maximum obtained heat gain is (1619W) for (0.5) 1pm flow rate ofwater.

A cylindrical insert for parabolic trough solar collector

2019 ◽  
Vol 29 (5) ◽  
pp. 1846-1876 ◽  
Author(s):  
Evangelos Bellos ◽  
Ilias Daniil ◽  
Christos Tzivanidis
Keyword(s):  
Heat Production ◽  
Solar Collector ◽  
Inlet Temperature ◽  
Parabolic Trough ◽  
Content Type ◽  
Work Demand ◽  
Thermal Enhancement ◽  
Overall Efficiency ◽  
Useful Heat ◽  
Parabolic Trough Solar Collector

Purpose The purpose of this paper is to investigate a cylindrical flow insert for a parabolic trough solar collector. Centrally placed and eccentric placed inserts are investigated in a systematic way to determine which configuration leads to the maximum thermal enhancement. Design/methodology/approach The analysis is performed in SolidWorks Flow Simulation with a validated computational fluid dynamics model. Moreover, the useful heat production and the pumping work demand increase are evaluated using the exergy and the overall efficiency criteria. The different scenarios are compared for inlet temperature of 600 K, flow rate of 100 L/min and Syltherm 800 as the working fluid. Moreover, the inlet temperature is examined from 450 to 650 K, and the diameter of the insert is investigated up to 50 mm. Findings According to the final results, the use of a cylindrical insert of 30 mm diameter is the most sustainable choice which leads to 0.56 per cent thermal efficiency enhancement. This insert was examined in various eccentric positions, and it is found that the optimum location is 10 mm over the initial position in the vertical direction. The thermal enhancement, in this case, is about 0.69 per cent. The pumping work demand was increased about three times with the insert of 30 mm, but the absolute values of this parameter are too low compared to the useful heat production. So, it is proved that the increase in the pumping work is not able to eliminate the useful heat production increase. Moreover, the thermal enhancement is found to be greater at higher temperature levels and can reach up to 1 per cent for an inlet temperature of r650 K. Originality/value The present work is a systematic investigation of the cylindrical flow insert in a parabolic trough collector. Different diameters of this insert, as well as different positions in two dimensions, are examined using a parametrization of angle-radius. To the authors’ knowledge, there is no other study in the literature that investigates the presented many cases systematically with the followed methodology on parabolic trough collectors. Moreover, the results of this work are evaluated with various criteria (thermal, exergy and overall efficiency), something which is not found in the literature.

The Dynamic Behavior of Once-Through Direct Steam Generation Parabolic Trough Solar Collector Row Under Moving Shadow Conditions

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Su Guo ◽  
Yinghao Chu ◽  
Deyou Liu ◽  
Xingying Chen ◽  
Chang Xu ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Dynamic Behavior ◽  
Mass Flow ◽  
Flow Rate ◽  
Solar Collector ◽  
Outlet Temperature ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Direct Steam ◽  
Parabolic Trough Solar Collector

Compared with recirculation and injection modes, once-through direct steam generation (DSG) parabolic troughs are simpler to construct and require the lowest investment. However, the heat transfer fluid (HTF) in once-through DSG parabolic trough systems has the most complicated dynamic behavior, particularly during periods of moving shadows caused by small clouds and jet contrails. In this paper, a nonlinear distributed parameter dynamic model (NDPDM) is proposed to model the dynamic behavior of once-through DSG parabolic trough solar collector row under moving shadow conditions. Compared with state-of-the-art models, the proposed NDPDM possesses three characteristics: (a) adopting real-time local values of the heat transfer and friction resistance coefficients, (b) simulating the whole collector row, including the boiler and the superheated sections, and (c) modeling the disturbance of direct normal irradiance (DNI) level on DSG parabolic trough solar collector row under moving shadow conditions. Validated using experimental data, the NDPDM accurately predicts the dynamic characteristics of HTF during periods of partial and moving DNI disturbance. The fundamental and specific dynamic process of fluid parameters for a DSG parabolic trough solar collector row is provided in this paper. The results show the following: (a) Moving shadows have a significant impact on the outlet temperature and mass flow rate, and the impact lasts up to 1000 s even after the shadows completely leave the collector row. (b) The time for outlet steam temperature to reach a steady-state value for the first time is independent of the shadow width, speed, and moving direction. (c) High-frequency chattering of the outlet mass flow rate can be observed under moving DNI disturbance and will have a longer duration if the shadow width is larger or the shadow speed is slower. Compared with cases in which the whole system is shaded, partially shading cases have shown a longer duration of high-frequency chattering. (d) Both wider widths and slower speeds of shadow will cause a larger amplitude of responses in the outlet temperature and mass flow rate. When the shadow speed is low, there is a longer delay time of response in the mass flow rate of the outlet fluid. (e) The amplitude of response in the outlet temperature does not depend on the direction of clouds movement. However, if the DNI disturbance starts at the inlet of the collector row, there will be significant delay times in both outlet temperature and mass flow rate, and a larger amplitude of response in outlet mass flow rate.

Sign in / Sign up

Export Citation Format

Share Document