Heat transfer fluids for parabolic trough solar collectors - a comparative study

2016 ◽  
Author(s):  
Reuben Buehler ◽  
Sam Yang ◽  
Juan C. Ordonez
Keyword(s):  
Heat Transfer ◽  
Comparative Study ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Heat Transfer Fluids

scholarly journals Contribution to the Parametric Study of the Performance of A Parabolic Trough Collector

2021 ◽  
Vol 321 ◽  
pp. 02016
Author(s):  
Belkacem Bouali ◽  
Hanane-Maria Regue
Keyword(s):  
Heat Transfer ◽  
Mass Flow ◽  
Flow Rate ◽  
Optimal Operation ◽  
Heat Transfer Fluid ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Heat Transfer Fluids ◽  
Ansys Cfx ◽  
Different Seasons

This paper presents an analysis of the performance of a parabolic trough collector (PTC) according to some key operating parameters. The effects of the secondary reflector, the length and thickness of the absorber tube (receiver tube) and the flow rate of the heat transfer fluid (HTF) are investigated. The main objective is to determine an optimal operation, which improves the performance of a traditional PTC. The target variables are the temperature at the outlet of the tube, the amount of energy collected by the HTF and the efficiency of the system. The solar flux data concern the city of LAGHOUAT located in the south of Algeria. Four days in different seasons are considered. The optical analysis of the system is performed by using the open source SolTrace code. The output of this analysis is used as a boundary condition for the CFD solver. The conjugate heat transfer and the fluid flow through the absorber tube are simulated by using ANSYS-CFX solver. Water is considered as heat transfer fluids. The obtained results show that the use of a curved secondary reflector significantly improves the performance of the traditional PTC. As the thickness of the tube increases, the heat storage in the material increases, which increases the temperature at the exit of the tube and therefore the efficiency of the system. However, the length of the tube depends on the mass flow of the HTF and vice versa. To keep the efficiency constant by choosing another length, it is necessary to choose a mass flow rate proportional to the flow rate corresponding to the initial length.

Volume Element Model for Modeling, Simulation, and Optimization of Parabolic Trough Solar Collectors

2017 ◽  
Author(s):  
Tugba S. Sensoy ◽  
Sam Yang ◽  
Juan C. Ordonez
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Mathematical Formulation ◽  
Element Model ◽  
Volume Element ◽  
Heat Transfer Fluid ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Simulation And Optimization ◽  
Proposed Model

In this paper we present a dynamic three-dimensional volume element model (VEM) of a parabolic trough solar collector (PTC) comprising an outer glass cover, annular space, absorber tube, and heat transfer fluid. The spatial domain in the VEM is discretized with lumped control volumes (i.e., volume elements) in cylindrical coordinates according to the predefined collector geometry; therefore, the spatial dependency of the model is taken into account without the need to solve partial differential equations. The proposed model combines principles of thermodynamics and heat transfer, along with empirical heat transfer correlations, to simplify the modeling and expedite the computations. The resulting system of ordinary differential equations is integrated in time, yielding temperature fields which can be visualized and assessed with scientific visualization tools. In addition to the mathematical formulation, we present the model validation using the experimental data provided in the literature, and conduct two simple case studies to investigate the collector performance as a function of annulus pressure for different gases as well as its dynamic behavior throughout a sunny day. The proposed model also exhibits computational advantages over conventional PTC models-the model has been written in Fortran with parallel computing capabilities. In summary, we elaborate the unique features of the proposed model coupled with enhanced computational characteristics, and demonstrate its suitability for future simulation and optimization of parabolic trough solar collectors.

scholarly journals Investigation of energetic and exergetic performances of parabolic trough collector with using different heat transfer fluids

2019 ◽  
Vol 111 ◽  
pp. 01054 ◽  
Author(s):  
F. Mertkan Arslan ◽  
Hüseyin Günerhan
Keyword(s):  
Heat Transfer ◽  
Energy Efficiency ◽  
Molten Salt ◽  
Sodium Nitrate ◽  
Potassium Nitrate ◽  
Parabolic Trough ◽  
Parabolic Trough Collector ◽  
Working Fluids ◽  
Selective Coating ◽  
Heat Transfer Fluids

In this study energetic and exergetic performances of parabolic trough collector is theoretically investigated by using 120 l/min synthetic ‘’Dowtherm A’’ oil , 1200 l/min Air at 100 bar (10 MPa) and 150 l/min molten salt which is mixture of 60 wt% sodium nitrate (NaNO3) and 40 wt% potassium nitrate (KNO3) which are widely used as heat transfer fluids. Fluids performance comparisons were performed with the LS-2 module, which is used with vacuum in annulus and Cermet as a selective coating. LS-2 module has 7.8 m receiver length and is 39 m2 aperture area. As a result, the maximum exergy efficiency of the molten salt, synthetic oil, Air to be 41.19% at 422 °C, 40.82% at 400 °C, 40.33% at 402 °C, respectively. The maximum exergy of air is higher than other working fluids up to 310 ° C but after about 310 ° C the exergy of the molten salt is higher than the others. The molten salt has the best energy efficiency at its operating temperatures (250 °C to 550 °C) than other working fluids.

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